Gene Summary

Gene:PDGFA; platelet derived growth factor subunit A
Aliases: PDGF1, PDGF-A
Summary:This gene encodes a member of the protein family comprised of both platelet-derived growth factors (PDGF) and vascular endothelial growth factors (VEGF). The encoded preproprotein is proteolytically processed to generate platelet-derived growth factor subunit A, which can homodimerize, or alternatively, heterodimerize with the related platelet-derived growth factor subunit B. These proteins bind and activate PDGF receptor tyrosine kinases, which play a role in a wide range of developmental processes. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2015]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:platelet-derived growth factor subunit A
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PDGFA (cancer-related)

Yu Y, Blokhuis BR, Garssen J, Redegeld FA
A Transcriptomic Insight into the Impact of Colon Cancer Cells on Mast Cells.
Int J Mol Sci. 2019; 20(7) [PubMed] Free Access to Full Article Related Publications
Mast cells (MCs) are one of the first immune cells recruited to a tumor. It is well recognized that MCs accumulate in colon cancer lesion and their density is associated with the clinical outcomes. However, the molecular mechanism of how colon cancer cells may modify MC function is still unclear. In this study, primary human MCs were generated from CD34⁺ progenitor cells and a 3D coculture model was developed to study the interplay between colon cancer cells and MCs. By comparing the transcriptomic profile of colon cancer-cocultured MCs versus control MCs, we identified a number of deregulated genes, such as MMP-2, VEGF-A, PDGF-A, COX2, NOTCH1 and ISG15, which contribute to the enrichment of cancer-related pathways. Intriguingly, pre-stimulation with a TLR2 agonist prior to colon cancer coculture induced upregulation of multiple interferon-inducible genes as well as MHC molecules in MCs. Our study provides an alternative approach to study the influence of colon cancer on MCs. The transcriptome signature of colon cancer-cocultured MCs may potentially reflect the mechanism of how colon cancer cells educate MCs to become pro-tumorigenic in the initial phase and how a subsequent inflammatory signal-e.g., TLR2 ligands-may modify their responses in the cancer milieu.

Tiwari A, Mukherjee B, Hassan MK, et al.
Reduced FRG1 expression promotes prostate cancer progression and affects prostate cancer cell migration and invasion.
BMC Cancer. 2019; 19(1):346 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Prostate cancer is the most common form of cancer in males and accounts for high cancer related deaths. Therapeutic advancement in prostate cancer has not been able to reduce the mortality burden of prostate cancer, which warrants further research. FRG1 which affects angiogenesis and cell migration in Xenopus, can be a potential player in tumorigenesis. In this study, we investigated the role of FRG1 in prostate cancer progression.
METHODS: Immunohistochemistry was performed to determine FRG1 expression in patient samples. FRG1 expression perturbation was done to investigate the effect of FRG1 on cell proliferation, migration and invasion, in DU145, PC3 and LNCaP cells. To understand the mechanism, we checked expression of various cytokines and MMPs by q-RT PCR, signaling molecules by western blot, in FRG1 perturbation sets. Results were validated by use of pharmacological inhibitor and activator and, western blot.
RESULTS: In prostate cancer tissue, FRG1 levels were significantly reduced, compared to the uninvolved counterpart. FRG1 expression showed variable effect on PC3 and DU145 cell proliferation. FRG1 levels consistently affected cell migration and invasion, in both DU145 and PC3 cells. Ectopic expression of FRG1 led to significant reduction in cell migration and invasion in both DU145 and PC3 cells, reverse trends were observed with FRG1 knockdown. In androgen receptor positive cell line LNCaP, FRG1 doesn't affect any of the cell properties. FRG1 knockdown led to significantly enhanced expression of GM-CSF, MMP1, PDGFA and CXCL1, in PC3 cells and, in DU145, it led to higher expression of GM-CSF, MMP1 and PLGF. Interestingly, FRG1 knockdown in both the cell lines led to activation of p38 MAPK. Pharmacological activation of p38 MAPK led to increase in the expression of GM-CSF and PLGF in DU145 whereas in PC3 it led to enhanced expression of GM-CSF, MMP1 and CXCL1. On the other hand, inhibition of p38 MAPK led to reduction in the expression of above mentioned cytokines.
CONCLUSION: FRG1 expression is reduced in prostate adenocarcinoma tissue. FRG1 expression affects migration and invasion in AR negative prostate cancer cells through known MMPs and cytokines, which may be mediated primarily via p38 MAPK activation.

Hoeman CM, Cordero FJ, Hu G, et al.
ACVR1 R206H cooperates with H3.1K27M in promoting diffuse intrinsic pontine glioma pathogenesis.
Nat Commun. 2019; 10(1):1023 [PubMed] Free Access to Full Article Related Publications
Diffuse intrinsic pontine glioma (DIPG) is an incurable pediatric brain tumor, with approximately 25% of DIPGs harboring activating ACVR1 mutations that commonly co-associate with H3.1K27M mutations. Here we show that in vitro expression of ACVR1 R206H with and without H3.1K27M upregulates mesenchymal markers and activates Stat3 signaling. In vivo expression of ACVR1 R206H or G328V with H3.1K27M and p53 deletion induces glioma-like lesions but is not sufficient for full gliomagenesis. However, in combination with PDGFA signaling, ACVR1 R206H and H3.1K27M significantly decrease survival and increase tumor incidence. Treatment of ACVR1 R206H mutant DIPGs with exogenous Noggin or the ACVR1 inhibitor LDN212854 significantly prolongs survival, with human ACVR1 mutant DIPG cell lines also being sensitive to LDN212854 treatment. Together, our results demonstrate that ACVR1 R206H and H3.1K27M promote tumor initiation, accelerate gliomagenesis, promote a mesenchymal profile partly due to Stat3 activation, and identify LDN212854 as a promising compound to treat DIPG.

Salha S, Gehmert S, Brébant V, et al.
PDGF regulated migration of mesenchymal stem cells towards malignancy acts via the PI3K signaling pathway.
Clin Hemorheol Microcirc. 2018; 70(4):543-551 [PubMed] Related Publications
INTRODUCTION: Mesenchymal stem cells (MSCs) have been described in breast cancer models to migrate towards carcinoma and integrate into tumor associated stroma supporting tumor growth, increasing their metastatic potency and contributing to tumor-angiogenesis. Platelet-derived growth factor (PDGF) isoforms (AA, BB, CC) stimulate growth, survival and motility of MSCs and certain other cell types. Noteworthy, breast carcinomas are known to express PDGF. We aim to further shed light on i) the relevance of the different PDGF isoforms on adipose tissue derived stem cells (ASCs) migration and ii) the underlying pathway dependent on PDGF stimulation.
MATERIALS AND METHODS: Breast cancer cell lines were purchased and ASC's were isolated from murine subcutaneous adipose tissue. The transmigration of ASC's towards the PDGF-isoforms was assessed by using recombinant human PDGF-AA, PDGF-BB and PDGF-CC in a trans-well culture dish system. Transmigrated ASC's were quantified in 5 randomly selected fields per condition using fluorescence microscopy after calcein-staining. PDGF-BB depended transmigration of ASC's was verified by downregulation and overexpression of PDGF-BB in breast cancer cell line using lentiviral vectors. In addition, a PI3-kinase inhibitor (LY294002) and a MAP-kinase inhibitor (PD98059) were used to identify the pathway involved in the PDGF-BB mediated migration of ASC's towards tumor.
RESULTS: ASC's transmigration significantly increased towards PDGF AA at 50 ng and only showed further increase by 500 ng which was similar to cell behavior when exposed to PDGF CC. In comparison, PDGF-BB significantly increased ASC's transmigration already at a low level of 5 ng with further significant increase for 20 ng and 40 ng. Cell transmigration was blocked with PDGFR-α antibodies but only for PDGF-AA and PDGF-CC whereas PDGFR-β blockage showed a significant effect on transmigration for PDGF-BB and PDGF-CC but not for PDGF-AA. Neutralizing antibodies in combination with PDGF receptor blockage confirmed findings. In addition, only PI3-kinase inhibitor but not the MEK-1 selective inhibitor caused a significant decrease of transmigration for ASCs towards breast cancer cells.
DISCUSSION: The transmigration of ASC's is most significantly enhanced by PDGF-BB via the PI3-kinase pathway. This data support that PI3-kinase is an important key player for MSC migration towards malignancy which need further research to prevent tumor progression in early disease stage.

Aula H, Skyttä T, Tuohinen S, et al.
Decreases in TGF-β1 and PDGF levels are associated with echocardiographic changes during adjuvant radiotherapy for breast cancer.
Radiat Oncol. 2018; 13(1):201 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Radiation-induced heart disease is mainly caused by activation of the fibrotic process. Transforming growth factor-beta 1 (TGF-β1) and platelet-derived growth factor (PDGF) are pro-fibrotic mediators. The aim of our study was to evaluate the behavior of TGF-β1 and PDGF during adjuvant radiotherapy (RT) for breast cancer and the association of these cytokines with echocardiographic changes.
METHODS: Our study included 73 women with early-stage breast cancer or ductal carcinoma in situ (DCIS) receiving post-operative RT but not chemotherapy. TGF-β1 and PDGF levels in serum samples taken before and on the last day of RT were measured by an enzyme-linked immunosorbent assay. Echocardiography was also performed at same time points. Patients were grouped according to a ≥ 15% worsening in tricuspid annular plane systolic excursion (TAPSE) and pericardium calibrated integrated backscatter (cIBS).
RESULTS: In all patients, the median TGF-β1 decreased from 25.0 (IQR 21.1-30.3) ng/ml to 23.6 (IQR 19.6-26.8) ng/ml (p = 0.003), and the median PDGF decreased from 18.0 (IQR 13.7-22.7) ng/ml to 15.6 (IQR 12.7-19.5) ng/ml (p < 0.001). The baseline TGF-β1, 30.7 (IQR 26.0-35.9) ng/l vs. 23.4 (IQR 20.1-27.3) ng/l (p < 0.001), and PDGF, 21.5. (IQR 15.7-31.2) ng/l vs. 16.9. (IQR 13.0-21.2) ng/ml, were higher in patients with a ≥ 15% decrease in TAPSE than in patients with a < 15% decrease. In patients with a ≥ 15% decrease in TAPSE, the median TGF-β1 decreased to 24.7 (IQR 20.0-29.8) ng/ml (p < 0.001), and the median PDGF decreased to 16.7 (IQR 12.9-20.9) ng/ml (p < 0.001). The patients with a < 15% decrease had stable TGF-β1 (p = 0.104), but PDGF decreased to 15.1 (IQR 12.5-18.6), p = 0.005. The patients with a ≥ 15% increase in cIBS exhibited a decrease in TGF-β1 from 26.0 (IQR 21.7-29.7) to 22.5 (IQR 16.6.-26.7) ng/ml, p < 0.001, and a decrease in PDGF from 19.8 (IQR 14.6-25.9) to 15.7 (IQR 12.8-20.2) ng/ml, p < 0.001. In patients with a < 15% increase, TGF-β1 and PDGF did not change significantly, p = 0.149 and p = 0.053, respectively.
CONCLUSION: We observed a decrease in TGF-β1 and PDGF levels during adjuvant RT for breast cancer. Echocardiographic changes, namely, in TAPSE and cIBS, were associated with a greater decrease in TGF-β1 and PDGF levels. Longer follow-up times will show whether these changes observed during RT translate into increased cardiovascular morbidity.

Obayashi-Ishii M, Saito S, Omagari D, et al.
A static magnetic field inhibits the expression of platelet-derived growth factor-AA in human oral squamous cell carcinoma.
J Oral Sci. 2018; 60(3):374-380 [PubMed] Related Publications
Magnetic attachments are commonly used for overdentures. The deleterious effects of exposure to magnetic flux on human health have not been substantiated so far; nevertheless, there is a need to understand the extent of magnetic field exposure in the oral area resulting from the use of magnetic attachments. The purpose of this study was to investigate the influence of a magnetic field on oral squamous cell carcinoma. Tumor cells cultured on a magnetic plate were compared with those not cultured on a magnetic plate (controls). The cells were seeded at a density of 1 × 10

Cheng CC, Liao PN, Ho AS, et al.
STAT3 exacerbates survival of cancer stem-like tumorspheres in EGFR-positive colorectal cancers: RNAseq analysis and therapeutic screening.
J Biomed Sci. 2018; 25(1):60 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Cancer stem cells are capable of undergoing cell division after surviving cancer therapies, leading to tumor progression and recurrence. Inhibitory agents against cancer stem cells may be therapeutically used for efficiently eradicating tumors. Therefore, the aim of this study was to identify the relevant driver genes that maintain cancer stemness in epidermal growth factor receptor (EGFR)-positive colorectal cancer (CRC) cells and to discover effective therapeutic agents against these genes.
METHODS: In this study, EGFR-positive cancer stem-like cells (CSLCs) derived from HCT116 and HT29 cells were used as study models for in vitro inductions. To identify the differential genes that maintain CSLCs, RNAseq analysis was conducted followed by bioinformatics analysis. Moreover, a panel containing 172 therapeutic agents targeting the various pathways of stem cells was used to identify effective therapeutics against CSLCs.
RESULTS: RNAseq analysis revealed that 654 and 840 genes were significantly upregulated and downregulated, respectively, in the HCT116 CSLCs. Among these genes, notably, platelet-derived growth factor A (PDGFA) and signal transducer and activator of transcription 3 (STAT3) were relevant according to the cancer pathway analyzed using NetworkAnalyst. Furthermore, therapeutic screening revealed that the agents targeting STAT3 and Wnt signaling pathways were efficient in reducing the cell viabilities of both HCT116 and HT29 cells. Consequently, we discovered that STAT3 inhibition using homoharringtonine and STAT3 knockdown significantly reduced the formation and survival of HT29-derived tumorspheres. We also observed that STAT3 phosphorylation was regulated by epidermal growth factor (EGF) to induce PDGFA and Wnt signaling cascades.
CONCLUSIONS: We identified the potential genes involved in tumorsphere formation and survival in selective EGFR-positive CRCs. The results reveal that the EGF-STAT3 signaling pathway promotes and maintains CRC stemness. In addition, a crosstalk between STAT3 and Wnt activates the Wnt/β-catenin signaling pathway, which is also responsible for cancer stemness. Thus, STAT3 is a putative therapeutic target for CRC treatment.

Cavallin LE, Ma Q, Naipauer J, et al.
KSHV-induced ligand mediated activation of PDGF receptor-alpha drives Kaposi's sarcomagenesis.
PLoS Pathog. 2018; 14(7):e1007175 [PubMed] Free Access to Full Article Related Publications
Kaposi's sarcoma (KS) herpesvirus (KSHV) causes KS, an angiogenic AIDS-associated spindle-cell neoplasm, by activating host oncogenic signaling cascades through autocrine and paracrine mechanisms. Tyrosine kinase receptor (RTK) proteomic arrays, identified PDGF receptor-alpha (PDGFRA) as the predominantly-activated RTK in KSHV-induced mouse KS-tumors. We show that: 1) KSHV lytic replication and the vGPCR can activate PDGFRA through upregulation of its ligands PDGFA/B, which increase c-myc, VEGF and KSHV gene expression in infected cells 2) KSHV infected spindle cells of most AIDS-KS lesions display robust phospho-PDGFRA staining 3) blocking PDGFRA-signaling with N-acetyl-cysteine, RTK-inhibitors Imatinib and Sunitinib, or dominant-negative PDGFRA inhibits tumorigenesis 4) PDGFRA D842V activating-mutation confers resistance to Imatinib in mouse-KS tumorigenesis. Our data show that KSHV usurps sarcomagenic PDGFRA signaling to drive KS. This and the fact that PDGFRA drives non-viral sarcomas highlights the importance for KSHV-induced ligand-mediated activation of PDGFRA in KS sarcomagenesis and shows that this oncogenic axis could be successfully blocked to impede KS tumor growth.

Bartoschek M, Pietras K
PDGF family function and prognostic value in tumor biology.
Biochem Biophys Res Commun. 2018; 503(2):984-990 [PubMed] Related Publications
The development and progression of a tumor depends on the close interaction of malignant cells and the supportive and suppressive tumor microenvironment. Paracrine signaling enables tumor cells to shape the surrounding tissue in order to decrease recognition by the immune system, attract blood vessels to fuel growth, change metabolic programs, and induce wound healing programs. In this study, we investigate the role of the platelet-derived growth factor (PDGF) family members PDGFA, PDGFB, PDGFC and PDGFD and their cognate tyrosine kinase receptors PDGFRA and PDGFRB, using publicly available data from The Cancer Genome Atlas and the Human Protein Atlas. Large scale analysis of expression correlation in RNA sequencing data from 7616 samples derived from 16 tumor types, revealed conserved functional programs in PDGF signaling in the majority of solid tumor types. Besides the well-known effects of PDGF signaling in mesenchymal cells, our analyses revealed a potential role of PDGF signaling in the composition of the immune microenvironment. We furthermore derived gene signatures with increased prognostic value for each PDGF family member. This study emphasizes the potential to impinge on specific paracrine signaling events to interfere with the crosstalk between malignant cells and their microenvironment.

Cimino PJ, Kim Y, Wu HJ, et al.
Genes Dev. 2018; 32(7-8):512-523 [PubMed] Free Access to Full Article Related Publications
Glioblastoma is the most frequently occurring and invariably fatal primary brain tumor in adults. The vast majority of glioblastomas is characterized by chromosomal copy number alterations, including gain of whole chromosome 7 and loss of whole chromosome 10. Gain of whole chromosome 7 is an early event in gliomagenesis that occurs in proneural-like precursor cells, which give rise to all isocitrate dehydrogenase (IDH) wild-type glioblastoma transcriptional subtypes.

Luengo-Gil G, Gonzalez-Billalabeitia E, Perez-Henarejos SA, et al.
Angiogenic role of miR-20a in breast cancer.
PLoS One. 2018; 13(4):e0194638 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Angiogenesis is a key process for tumor progression and a target for treatment. However, the regulation of breast cancer angiogenesis and its relevance for clinical resistance to antiangiogenic drugs is still incompletely understood. Recent developments on the contribution of microRNA to tumor angiogenesis and on the oncogenic effects of miR-17-92, a miRNA cluster, point to their potential role on breast cancer angiogenesis. The aim of this work was to establish the contribution of miR-20a, a member of miR-17-92 cluster, to tumor angiogenesis in patients with invasive breast carcinoma.
METHODS: Tube-formation in vitro assays with conditioned medium from MCF7 and MDA-MB-231 breast cancer cell lines were performed after transfection with miR-20a and anti-miR20a. For clinical validation of the experimental findings, we performed a retrospective analysis of a series of consecutive breast cancer patients (n = 108) treated with neoadjuvant chemotherapy and with a full characterization of their vessel pattern and expression of angiogenic markers in pre-treatment biopsies. Expression of members of the cluster miR-17-92 and of angiogenic markers was determined by RT-qPCR after RNA purification from FFPE samples.
RESULTS: In vitro angiogenesis assays with endothelial cells and conditioned media from breast cancer cell lines showed that transfection with anti-miR20a in MDA-MB-231 significantly decreased mean mesh size and total mesh area, while transfection with miR-20a in MCF7 cells increased mean mesh size. MiR-20a angiogenic effects were abrogated by treatment with aflibercept, a VEGF trap. These results were supported by clinical data showing that mir-20a expression was higher in tumors with no estrogen receptor or with more extensive nodal involvement (cN2-3). A higher miR-20a expression was associated with higher mean vessel size (p = 0.015) and with an angiogenic pattern consisting in larger vessels, higher VEGFA expression and presence of glomeruloid microvascular proliferations (p<0.001). This association was independent of tumor subtype and VEGFA expression.
CONCLUSIONS: Transfection of breast cancer cells with miR-20a induces vascular changes in endothelial tube-formation assays. Expression of miR-20a in breast invasive carcinomas is associated with a distinctive angiogenic pattern consisting in large vessels, anomalous glomeruloid microvascular proliferations and high VEGFA expression. Our results suggest a role for miR-20a in the regulation of breast cancer angiogenesis, and raise the possibility of its use as an angiogenic biomarker.

Eiro N, González L, Martínez-Ordoñez A, et al.
Cancer-associated fibroblasts affect breast cancer cell gene expression, invasion and angiogenesis.
Cell Oncol (Dordr). 2018; 41(4):369-378 [PubMed] Related Publications
PURPOSE: It has been reported that stromal cell features may affect the clinical outcome of breast cancer patients. Cancer associated fibroblasts (CAFs) represent one of the most abundant cell types within the breast cancer stroma. Here, we aimed to explore the influence of CAFs on breast cancer gene expression, as well as on invasion and angiogenesis.
METHODS: qRT-PCR was used to evaluate the expression of several cancer progression related genes (S100A4, TGFβ, FGF2, FGF7, PDGFA, PDGFB, VEGFA, IL-6, IL-8, uPA, MMP2, MMP9, MMP11 and TIMP1) in the human breast cancer-derived cell lines MCF-7 and MDA-MB-231, before and after co-culture with CAFs. Stromal mononuclear inflammatory cell (MIC) MMP11 expression was used to stratify primary tumors. In addition, we assessed the in vitro effects of CAFs on both MDA-MB-231 breast cancer cell invasion and endothelial cell (HUVEC) tube formation.
RESULTS: We found that the expression levels of most of the genes tested were significantly increased in both breast cancer-derived cell lines after co-culture with CAFs from either MMP11+ or MMP11- MIC tumors. IL-6 and IL-8 showed an increased expression in both cancer-derived cell lines after co-culture with CAFs from MMP11+ MIC tumors. We also found that the invasive and angiogenic capacities of, respectively, MDA-MB-231 and HUVEC cells were increased after co-culture with CAFs, especially those from MMP11+ MIC tumors.
CONCLUSIONS: Our data indicate that tumor-derived CAFs can induce up-regulation of genes involved in breast cancer progression. Our data additionally indicate that CAFs, especially those derived from MMP11+ MIC tumors, can promote breast cancer cell invasion and angiogenesis.

Adewuyi EE, Deschenes J, Lopez-Campistrous A, et al.
Autocrine activation of platelet-derived growth factor receptor α in metastatic papillary thyroid cancer.
Hum Pathol. 2018; 75:146-153 [PubMed] Related Publications
Metastatic dissemination of papillary thyroid cancer has been reported to be strongly associated with expression of platelet-derived growth factor (PDGFR) α and altered TTF1 function. However, the status of PDGF ligands in papillary thyroid cancer and the potential role of these ligands in metastatic disease are obscure. We assessed the prevalence of PDGF ligands in benign and malignant thyroid tumors to determine if ligand upregulation is associated with α-isoform (PDGF-AA or PDGF-BB) or the β-isoform (PDGF-BB or PDGF-DD) of PDGFR in individual tumors. The immunohistochemical expression of PDGFRα, PDGF-AA, PDGF-BB, and PDGF-DD was surveyed in follicular adenomas (n=55), papillary thyroid carcinomas (103 with and 59 without nodal metastases), and lymph node metastasis (n=12). There is an augmented tendency for PDGF-AA expression in node-positive papillary thyroid cancer metastases (P<.0001). Although PDGF-BB and -DD were commonly identified, there was no relationship between the presence of these cytokines and malignant disease or metastases. Logistic regression demonstrated that PDGF-AA expression was significantly associated with the presence of PDGFRα (odds ratio=4.6, P=.004) and recurrent disease. When either PDGFRα or PDGF-AA was used to predict the presence of metastases, the sensitivity achieved was 86% and 88%, respectively, whereas specificities were lower at 71% and 61%, respectively. The augmented coexpression of PDGF-AA and PDGFRα in metastatic papillary thyroid cancers suggests that an autocrine signaling loop may contribute to nodal infiltration. Combined testing for the expression of PDGF-AA and PDGFRα may identify those patients with papillary thyroid cancer at risk of metastatic disease and resistance to therapy.

Makondi PT, Lee CH, Huang CY, et al.
Prediction of novel target genes and pathways involved in bevacizumab-resistant colorectal cancer.
PLoS One. 2018; 13(1):e0189582 [PubMed] Free Access to Full Article Related Publications
Bevacizumab combined with cytotoxic chemotherapy is the backbone of metastatic colorectal cancer (mCRC) therapy; however, its treatment efficacy is hampered by therapeutic resistance. Therefore, understanding the mechanisms underlying bevacizumab resistance is crucial to increasing the therapeutic efficacy of bevacizumab. The Gene Expression Omnibus (GEO) database (dataset, GSE86525) was used to identify the key genes and pathways involved in bevacizumab-resistant mCRC. The GEO2R web tool was used to identify differentially expressed genes (DEGs). Functional and pathway enrichment analyses of the DEGs were performed using the Database for Annotation, Visualization, and Integrated Discovery(DAVID). Protein-protein interaction (PPI) networks were established using the Search Tool for the Retrieval of Interacting Genes/Proteins database(STRING) and visualized using Cytoscape software. A total of 124 DEGs were obtained, 57 of which upregulated and 67 were downregulated. PPI network analysis showed that seven upregulated genes and nine downregulated genes exhibited high PPI degrees. In the functional enrichment, the DEGs were mainly enriched in negative regulation of phosphate metabolic process and positive regulation of cell cycle process gene ontologies (GOs); the enriched pathways were the phosphoinositide 3-kinase-serine/threonine kinase signaling pathway, bladder cancer, and microRNAs in cancer. Cyclin-dependent kinase inhibitor 1A(CDKN1A), toll-like receptor 4 (TLR4), CD19 molecule (CD19), breast cancer 1, early onset (BRCA1), platelet-derived growth factor subunit A (PDGFA), and matrix metallopeptidase 1 (MMP1) were the DEGs involved in the pathways and the PPIs. The clinical validation of the DEGs in mCRC (TNM clinical stages 3 and 4) revealed that high PDGFA expression levels were associated with poor overall survival, whereas high BRCA1 and MMP1 expression levels were associated with favorable progress free survival(PFS). The identified genes and pathways can be potential targets and predictors of therapeutic resistance and prognosis in bevacizumab-treated patients with mCRC.

Xu R, Ji J, Zhang X, et al.
PDGFA/PDGFRα-regulated GOLM1 promotes human glioma progression through activation of AKT.
J Exp Clin Cancer Res. 2017; 36(1):193 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Golgi Membrane Protein 1 (GOLM1), a protein involved in the trafficking of proteins through the Golgi apparatus, has been shown to be oncogenic in a variety of human cancers. Here, we examined the role of GOLM1 in the development of human glioma.
METHODS: qRT-PCR, immunohistochemistry, and western blot analysis were performed to evaluate GOLM1 levels in cell lines and a cohort of primary human glioma and non-neoplastic brain tissue samples. Glioma cell lines were modified with lentiviral constructs expressing short hairpin RNAs targeting GOLM1 or overexpressing the protein to assess function in proliferation, viability, and migration and invasion in vitro using EdU, CCK8, clone-forming, Transwell assays, 3D tumor spheroid invasion assay and in vivo in orthotopic implantations. Protein lysates were used to screen a membrane-based antibody array to identify kinases mediated by GOLM1. Specific inhibitors of PDGFRα (AG1296) and AKT (MK-2206) were used to examine the regulation of PDGFA/PDGFRα on GOLM1 and the underlying pathway respectively.
RESULTS: qRT-PCR, immunohistochemistry and western blot analysis revealed GOLM1 expression to be elevated in glioma tissues and cell lines. Silencing of GOLM1 attenuated proliferation, migration, and invasion of U251, A172 and P3#GBM (primary glioma) cells, while overexpression of GOLM1 enhanced malignant behavior of U87MG cells. We further demonstrated that activation of AKT is the driving force of GOLM1-promoted glioma progression. The last finding of this research belongs to the regulation of PDGFA/PDGFRα on GOLM1, while GOLM1 was also a key element of PDGFA/PDGFRα-mediated activation of AKT, as well as the progression of glioma cells.
CONCLUSIONS: PDGFA/PDGFRα-regulated GOLM1 promotes glioma progression possibly through activation of a key signaling kinase, AKT. GOLM1 interference may therefore provide a novel therapeutic target and improve the efficacy of glioma treatment, particularly in the case of the proneural molecular subtype of human glioma.

von Mehren M, Joensuu H
Gastrointestinal Stromal Tumors.
J Clin Oncol. 2018; 36(2):136-143 [PubMed] Free Access to Full Article Related Publications
GI stromal tumors (GISTs) are neoplasms with a varying malignancy potential ranging from virtually indolent tumors to rapidly progressing cancers. GISTs occur throughout the intestinal tract, and most harbor an activating mutation in either KIT or platelet-derived growth factor A ( PDGFRA). Diagnosis is made using immunohistochemistry, but molecular testing with mutation analysis is paramount for selection of appropriate therapy. Most small GISTs are cured with surgery. Tyrosine kinase inhibitor (TKI) therapy has led to substantial improvements in survival, both for patients with localized GIST and those with advanced disease. Adjuvant therapy with imatinib benefits patients with a high risk of recurrence, with studies suggesting most benefit with at least 3 years of therapy. Neoadjuvant imatinib therapy should be considered for patients requiring extensive surgery, aiming at shrinking the tumor to allow organ preservation and less extensive surgery. The following three TKIs have been approved for the management of advanced disease: imatinib, sunitinib, and regorafenib; imatinib is usually the best tolerated of the three and the standard first-line treatment. TKIs benefit the majority of patients with advanced GIST but have no or limited efficacy in patients with the PDGFRA D842V mutation or patients with GIST lacking KIT and PDGFRA mutations. Surgery, the mainstay of primary tumor management, also plays a role in the advanced disease setting for selected patients, as do some other approaches such as palliative radiation therapy. Research continues to identify novel therapies, in particular effective agents to treat TKI-refractory disease.

Sandoval-Bórquez A, Polakovicova I, Carrasco-Véliz N, et al.
MicroRNA-335-5p is a potential suppressor of metastasis and invasion in gastric cancer.
Clin Epigenetics. 2017; 9:114 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Multiple aberrant microRNA expression has been reported in gastric cancer. Among them, microRNA-335-5p (miR-335), a microRNA regulated by DNA methylation, has been reported to possess both tumor suppressor and tumor promoter activities.
RESULTS: Herein, we show that miR-335 levels are reduced in gastric cancer and significantly associate with lymph node metastasis, depth of tumor invasion, and ultimately poor patient survival in a cohort of Amerindian/Hispanic patients. In two gastric cancer cell lines AGS and, Hs 746T the exogenous miR-335 decreases migration, invasion, viability, and anchorage-independent cell growth capacities. Performing a PCR array on cells transfected with miR-335, 19 (30.6%) out of 62 genes involved in metastasis and tumor invasion showed decreased transcription levels. Network enrichment analysis narrowed these genes to nine (PLAUR, CDH11, COL4A2, CTGF, CTSK, MMP7, PDGFA, TIMP1, and TIMP2). Elevated levels of PLAUR, a validated target gene, and CDH11 were confirmed in tumors with low expression of miR-335. The 3'UTR of CDH11 was identified to be directly targeted by miR-335. Downregulation of miR-335 was also demonstrated in plasma samples from gastric cancer patients and inversely correlated with DNA methylation of promoter region (Z = 1.96,
CONCLUSIONS: Comprehensive evaluation of metastasis and invasion pathway identified a subset of associated genes and confirmed PLAUR and CDH11, both targets of miR-335, to be overexpressed in gastric cancer tissues. DNA methylation of miR-335 may be a promissory strategy for non-invasive approach to gastric cancer.

Fan KJ, Yang B, Liu Y, et al.
Inhibition of human lung cancer proliferation through targeting stromal fibroblasts by dihydromyricetin.
Mol Med Rep. 2017; 16(6):9758-9762 [PubMed] Related Publications
In the present study, the effects of dihydromyricetin on the proliferative potential of fibroblasts and lung carcinoma cells were investigated. Markedly higher expression levels of smooth muscle actin and platelet derived growth factors (PDGFs) were observed in the fibroblasts using reverse transcription-polymerase chain reaction analysis. The expression levels of PDGF-A and PDGF-B were also higher in the lung cancer cells. Western blot analysis revealed higher expression levels of the receptor for platelet-derived growth factor (PDGFRβ) in the lysates from fibroblasts obtained from normal tissues and carcinoma tissues. Treatment of the fibroblasts with dihydromyricetin inhibited the expression of PDGFRβ when treated with a 10 µM concentration for 48 h. Treatment of the fibroblasts with a 10 µM concentration of dihydromyricetin for 48 h led to complete inhibition of the activation of extracellular signal-regulated kinase (Erk)1/2 and Akt. The results of an MTT assay showed that treatment of the fibroblasts with dihydromyricetin significantly reduced the PDGF-mediated increase in the rate of proliferation. The rate of proliferation of the A549 lung cancer cells cultured with fibroblasts was markedly increased, compared with that of the A549 cells cultured alone. However, dihydromyricetin significantly (P<0.05) inhibited the proliferation rate of the A549 cells cultured with fibroblasts, compared with the untreated cultures. The proliferation rates of the A549 cancer cells, A549 cells cultured with fibroblasts, and A549 cells cultured with fibroblasts and treated with dihydromyricetin were found to be were 78.45, 98.45 and 21.37%, respectively. Dihydromyricetin inhibited the proliferative potential of fibroblasts in the lung cancer cells through targeting the activation of Erk1/2 and Akt. Therefore, there is scope for dihydromyricetin to be evaluated further for the treatment of lung cancer.

Lee J, Lee J, Yun JH, et al.
Autocrine DUSP28 signaling mediates pancreatic cancer malignancy via regulation of PDGF-A.
Sci Rep. 2017; 7(1):12760 [PubMed] Free Access to Full Article Related Publications
Pancreatic cancer remains one of the most deadly cancers with a grave prognosis. Despite continuous efforts to improve remedial values, limited progress has been made. We have reported that dual specificity phosphatase 28 (DUSP28) has a critical role of chemo-resistance and migration in pancreatic cancers. However, its mechanism remains unclear. Here, we further clarify the function of DUSP28 in pancreatic cancers. Analysis using a public microarray database and in vitro assay indicated a critical role of platelet derived growth factor A (PDGF-A) in pancreatic cancer malignancy. PDGF-A was positively regulated by DUSP28 expression at the mRNA and protein levels. Enhanced DUSP28 sensitized pancreatic cancer cells to exogenous PDGF-A treatment in migration, invasion, and proliferation. Transfection with siRNA targeting DUSP28 blunted the influence of administered PDGF-A by inhibition of phosphorylation of FAK, ERK1/2, and p38 signalling pathways. In addition, DUSP28 and PDGF-A formed an acquired autonomous autocrine-signaling pathway. Furthermore, targeting DUSP28 inhibited the tumor growth and migratory features through the blockade of PDGF-A expression and intracellular signaling in vivo. Our results establish novel insight into DUSP28 and PDGF-A related autonomous signaling pathway in pancreatic cancer.

Vastrad B, Vastrad C, Godavarthi A, Chandrashekar R
Molecular mechanisms underlying gliomas and glioblastoma pathogenesis revealed by bioinformatics analysis of microarray data.
Med Oncol. 2017; 34(11):182 [PubMed] Related Publications
The aim of this study was to identify key genes associated with gliomas and glioblastoma and to explore the related signaling pathways. Gene expression profiles of three glioma stem cell line samples, three normal astrocyte samples, three astrocyte overexpressing 4 iPSC-inducing and oncogenic factors (myc(T58A), OCT-4, p53DD, and H-Ras(G12V)) samples, three astrocyte overexpressing 7 iPSC-inducing and oncogenic factors (OCT4, H-Ras(G12V), myc(T58A), p53DD, cyclin D1, CDK4(RC24) and hTERT) samples and three glioblastoma cell line samples were downloaded from the ArrayExpress database (accession: E-MTAB-4771). The differentially expressed genes (DEGs) in gliomas and glioblastoma were identified using FDR and t tests, and protein-protein interaction (PPI) networks for these DEGs were constructed using the protein interaction network analysis. The GeneTrail2 1.5 tool was used to identify potentially enriched biological processes among the DEGs using gene ontology (GO) terms and to identify the related pathways using the Kyoto Encyclopedia of Genes and Genomes, Reactome and WikiPathways pathway database. In addition, crucial modules of the constructed PPI networks were identified using the PEWCC1 plug-in, and their topological properties were analyzed using NetworkAnalyzer, both available from Cytoscape. We also constructed microRNA-target gene regulatory network and transcription factor-target gene regulatory network for these DEGs were constructed using the miRNet and binding and expression target analysis. We identified 200 genes that could potentially be involved in the gliomas and glioblastoma. Among them, bioinformatics analysis identified 137 up-regulated and 63 down-regulated DEGs in gliomas and glioblastoma. The significant enriched pathway (PI3K-Akt) for up-regulated genes such as COL4A1, COL4A2, EGFR, FGFR1, LAPR6, MYC, PDGFA, SPP1 were selected as well as significant GO term (ear development) for up-regulated genes such as CELSR1, CHRNA9, DDR1, FGFR1, GLI2, LGR5, SOX2, TSHR were selected, while the significant enriched pathway (amebiasis) for down-regulated gene such as COL3A1, COL5A2, LAMA2 were selected as well as significant GO term (RNA polymerase II core promoter proximal region sequence-specific binding (5) such as MEIS2, MEOX2, NR2E1, PITX2, TFAP2B, ZFPM2 were selected. Importantly, MYC and SOX2 were hub proteins in the up-regulated PPI network, while MET and CDKN2A were hub proteins in the down-regulated PPI network. After network module analysis, MYC, FGFR1 and HOXA10 were selected as the up-regulated coexpressed genes in the gliomas and glioblastoma, while SH3GL3 and SNRPN were selected as the down-regulated coexpressed genes in the gliomas and glioblastoma. MicroRNA hsa-mir-22-3p had a regulatory effect on the most up DEGs, including VSNL1, while hsa-mir-103a-3p had a regulatory effect on the most down DEGs, including DAPK1. Transcription factor EZH2 had a regulatory effect on the both up and down DEGs, including CD9, CHI3L1, MEIS2 and NR2E1. The DEGs, such as MYC, FGFR1, CDKN2A, HOXA10 and MET, may be used for targeted diagnosis and treatment of gliomas and glioblastoma.

Hocker SE, Higginbotham ML, Schermerhorn T, Henningson J
Receptor tyrosine kinase expression and phosphorylation in canine nasal carcinoma.
Res Vet Sci. 2017; 115:484-489 [PubMed] Related Publications
Preliminary studies have supported use of toceranib phosphate (Palladia®) in treatment of canine nasal carcinomas, though the mechanisms of its activity are unknown. This study evaluated sixteen canine nasal carcinoma and five normal nasal epithelium samples for expression and phosphorylation of known targets of toceranib [vascular endothelial growth factor receptor-2 (VEGR2), platelet derived growth factor alpha (PDGFR-α), platelet derived growth factor receptor beta (PDGFR-β), and stem cell factor receptor (c-KIT)] and epidermal growth factor receptor 1 (EGFR1) using immunohistochemistry, RT-PCR and a receptor tyrosine kinase (RTK) phosphorylation panel. Protein for VEGFR2 was expressed in all carcinomas, PDGFR-α was noted in 15/16, whereas PDGFR-β was detected in 3/16 samples, but showed significant stromal staining. Protein expression for c-KIT was present in 4/16 and EGFR1 was noted in 14/16 samples. Normal tissue showed variable protein expression of the RTKs. Messenger RNA for VEGFR2, PDGFR-β, and c-KIT were noted in all samples. Messenger RNA for PDGFR-α and EGFR1 were detected in 15/16 samples. All normal nasal tissue detected messenger RNA. Phosphorylation of VEGFR2, PDGFR-α, PDGFR-β and c-KIT was not observed in any carcinoma or normal nasal sample, but phosphorylation of EGFR1 was noted in 10/16 carcinoma and 3/5 normal samples. The absence of phosphorylated RTK targets of toceranib suggests any clinical effect of toceranib occurs through inhibition of alternative unidentified RTK pathways in canine nasal carcinomas. The observed protein and message expression and phosphorylation of EGFR1 in the nasal carcinoma samples merits further inquiry into EGFR1 as a therapeutic target for this cancer.

Hong B, Yang Y, Guo S, et al.
Intra-tumour molecular heterogeneity of clear cell renal cell carcinoma reveals the diversity of the response to targeted therapies using patient-derived xenograft models.
Oncotarget. 2017; 8(30):49839-49850 [PubMed] Free Access to Full Article Related Publications
Inter- and intra-tumour molecular heterogeneity is increasingly recognized in clear cell renal cell carcinoma (ccRCC). It may partially explain the diversity of responses to targeted therapies and the various clinical outcomes. In this study, a 56-year-old male ccRCC patient with multiple metastases received radical nephrectomy and resection of the metastatic tumour in chest wall. The surgical specimens were implanted into nude mice to establish patient-derived xenograft (PDX) models with KI2367 model derived from the primary tumour and KI2368 model from the metastastic tumour. The two modles were treated with Sorafenib, Sunitinib, Axitinib, combined Sorafenib/Sunitinib, or alternating therapy of Sorafenib and Sunitinib. Significant anti-tumour activity was found in KI2367 treated with Sorafenib/Sunitinib monotherapy, combined Sorafenib/Sunitinib, and alternating therapy of Sorafenib/Sunitinib (P<0.05) but not in that treated with Axitinib monotherapy. In contrast, KI2368 was significantly responsive to Sunitinib monotherapy, combined Sorafenib/Sunitinib therapy and alternating therapy of Sorafenib/Sunitinib but not responsive to Sorafenib and Axitinib monotherapy (P<0.05). RNAseq of the two models demonstrated that the expression levels of 1,725 genes including the drug targeted genes of PDGFA, PDGFB and PDGFRA were >5-fold higher in KI2367 than in KI2368 and the expression levels of 994 genes were > 5-fold higher in KI2368 than in KI2367. These results suggest the presence of intra-tumour molecular heterogeneity in this patient. This heterogeneity may influence the response to targeted therapies. Multiple biopsy, liquid biopsy and genomic analysis of intra- tumour molecular heterogeneity may help guide a more precise and effective plan in selecting targeted therapies for ccRCC patients.

Zhang Y, Cruickshanks N, Yuan F, et al.
Targetable T-type Calcium Channels Drive Glioblastoma.
Cancer Res. 2017; 77(13):3479-3490 [PubMed] Free Access to Full Article Related Publications
Glioblastoma (GBM) stem-like cells (GSC) promote tumor initiation, progression, and therapeutic resistance. Here, we show how GSCs can be targeted by the FDA-approved drug mibefradil, which inhibits the T-type calcium channel Cav3.2. This calcium channel was highly expressed in human GBM specimens and enriched in GSCs. Analyses of the The Cancer Genome Atlas and REMBRANDT databases confirmed upregulation of Cav3.2 in a subset of tumors and showed that overexpression associated with worse prognosis. Mibefradil treatment or RNAi-mediated attenuation of Cav3.2 was sufficient to inhibit the growth, survival, and stemness of GSCs and also sensitized them to temozolomide chemotherapy. Proteomic and transcriptomic analyses revealed that Cav3.2 inhibition altered cancer signaling pathways and gene transcription. Cav3.2 inhibition suppressed GSC growth in part by inhibiting prosurvival AKT/mTOR pathways and stimulating proapoptotic survivin and BAX pathways. Furthermore, Cav3.2 inhibition decreased expression of oncogenes (PDGFA, PDGFB, and TGFB1) and increased expression of tumor suppressor genes (TNFRSF14 and HSD17B14). Oral administration of mibefradil inhibited growth of GSC-derived GBM murine xenografts, prolonged host survival, and sensitized tumors to temozolomide treatment. Our results offer a comprehensive characterization of Cav3.2 in GBM tumors and GSCs and provide a preclinical proof of concept for repurposing mibefradil as a mechanism-based treatment strategy for GBM.

Yang QL, Zhang LY, Wang HF, et al.
The N-terminal polypeptide derived from viral macrophage inflammatory protein II reverses breast cancer epithelial-to-mesenchymal transition via a PDGFRα-dependent mechanism.
Oncotarget. 2017; 8(23):37448-37463 [PubMed] Free Access to Full Article Related Publications
NT21MP, a 21-residue peptide derived from the viral macrophage inflammatory protein II, competed effectively with the natural ligand of CXC chemokine receptor 4 (CXCR4), stromal cell-derived factor 1-alpha, to induce apoptosis and inhibit growth in breast cancer. Its role in tumor epithelial-to-mesenchymal transition (EMT) regulation remains unknown. In this study, we evaluated the reversal of EMT upon NT21MP treatment and examined its role in the inhibition of EMT in breast cancer. The parental cells of breast cancer (SKBR-3 and MCF-7) and paclitaxel-resistant (SKBR-3 PR and MCF-7 PR) cells were studied in vitro and in combined immunodeficient mice. The mice injected with SKBR-3 PR cells were treated with NT21MP through the tail vein or intraperitoneally with paclitaxel or saline. Sections from tumors were evaluated for tumor weight and EMT markers based on Western blot. In vitro, the effects of NT21MP, CXCR4 and PDGFRα on tumor EMT were assessed by relative quantitative real-time reverse transcription-polymerase chain reaction, western blot and biological activity in breast cancer cell lines expressing high or low levels of CXCR4. Our results illustrated that NT21MP could reverse the phenotype of EMT in paclitaxel-resistant cells. Furthermore, we found that NT21MP governed PR-mediated EMT partly due to controlling platelet-derived growth factors A and B (PDGFA and PDGFB) and their receptor (PDGFRα). More importantly, NT21MP down-regulated AKT and ERK1/2 activity, which were activated by PDGFRα, and eventually reversed the EMT. Together, these results indicated that CXCR4 overexpression drives acquired paclitaxel resistance, partly by activating the PDGFA and PDGFB/PDGFRα autocrine signaling loops that activate AKT and ERK1/2. Inhibition of the oncogenic EMT process by targeting CXCR4/PDGFRα-mediated pathways using NT21MP may provide a novel therapeutic approach towards breast cancer.

Connolly NP, Stokum JA, Schneider CS, et al.
Genetically engineered rat gliomas: PDGF-driven tumor initiation and progression in tv-a transgenic rats recreate key features of human brain cancer.
PLoS One. 2017; 12(3):e0174557 [PubMed] Free Access to Full Article Related Publications
Previously rodent preclinical research in gliomas frequently involved implantation of cell lines such as C6 and 9L into the rat brain. More recently, mouse models have taken over, the genetic manipulability of the mouse allowing the creation of genetically accurate models outweighed the disadvantage of its smaller brain size that limited time allowed for tumor progression. Here we illustrate a method that allows glioma formation in the rat using the replication competent avian-like sarcoma (RCAS) virus / tumor virus receptor-A (tv-a) transgenic system of post-natal cell type-specific gene transfer. The RCAS/tv-a model has emerged as a particularly versatile and accurate modeling technology by enabling spatial, temporal, and cell type-specific control of individual gene transformations and providing de novo formed glial tumors with distinct molecular subtypes mirroring human GBM. Nestin promoter-driven tv-a (Ntv-a) transgenic Sprague-Dawley rat founder lines were created and RCAS PDGFA and p53 shRNA constructs were used to initiate intracranial brain tumor formation. Tumor formation and progression were confirmed and visualized by magnetic resonance imaging (MRI) and spectroscopy. The tumors were analyzed using histopathological and immunofluorescent techniques. All experimental animals developed large, heterogeneous brain tumors that closely resembled human GBM. Median survival was 92 days from tumor initiation and 62 days from the first point of tumor visualization on MRI. Each tumor-bearing animal showed time dependent evidence of malignant progression to high-grade glioma by MRI and neurological examination. Post-mortem tumor analysis demonstrated the presence of several key characteristics of human GBM, including high levels of tumor cell proliferation, pseudopalisading necrosis, microvascular proliferation, invasion of tumor cells into surrounding tissues, peri-tumoral reactive astrogliosis, lymphocyte infiltration, presence of numerous tumor-associated microglia- and bone marrow-derived macrophages, and the formation of stem-like cell niches within the tumor. This transgenic rat model may enable detailed interspecies comparisons of fundamental cancer pathways and clinically relevant experimental imaging procedures and interventions that are limited by the smaller size of the mouse brain.

Ong HS, Gokavarapu S, Tian Z, et al.
PDGFRA mRNA is overexpressed in oral cancer patients as compared to normal subjects with a significant trend of overexpression among tobacco users.
J Oral Pathol Med. 2017; 46(8):591-597 [PubMed] Related Publications
BACKGROUND: Platelet-derived growth factors alpha (PDGFA) is a tyrosine kinase receptor activator which is known to be amplified in the malignancies, and their expression levels are correlated to tumor progression and reduced overall survival. The expression of PDGFRA is different among the tumors and normal tissues; furthermore, their expression level is site specific. Under a physiological condition, PDGFRA and its ligand are expressed in distinct cell populations and activated in a paracrine manner. Nevertheless, heterodimer characteristic of PDGFRA allows it to be trans-activated by non-specific ligands or via autocrine manner. The future of cancer therapy can be based on PDGFRA receptor blockade and therefore warrants further investigation to determine the differing expression of PDGFRA between controls and patients with oral squamous cell carcinoma (OSCC).
METHODS: We performed a case-control study of 111 patients with newly diagnosed tongue squamous cell carcinoma and 111 control subjects without a cancer diagnosis, matched for age and gender, to evaluate the association between PDGFRA expression levels in oral mucosa. We then performed smoking stratification in each cohort. Independent t test analysis was applied for case-control comparisons.
RESULTS: Mean value of PDGFRA mRNA level (-ΔCt) for normal cohort is -30.242, whereas mean value of PDGFRA mRNA level for patients with OSCC is -11.516. PDGFRA mRNA level (-ΔCt) was significantly higher in oral cancer cohort, P<.001. Smokers have a significantly higher PDGFRA mRNA expression in comparison with non-smokers (P=.002) among the non-cancer group. Likewise, this trend is observed in cancer cohort too, P=.044.
CONCLUSION: PDGFRA expression is significantly higher in oral cancer cohort with or without the establishment of tobacco risk factor.

Pan HD, Peng YF, Xiao G, Gu J
High levels of serum platelet-derived growth factor-AA and human epidermal growth factor receptor-2 are predictors of colorectal cancer liver metastasis.
World J Gastroenterol. 2017; 23(7):1233-1240 [PubMed] Free Access to Full Article Related Publications
AIM: To develop predictive markers in blood for colorectal cancer liver metastasis.
METHODS: Twenty colorectal cancer patients were selected and divided into two groups. Group A consisted of 10 patients whose pathological TNM stage was IIIC (T3-4N2M0), while another 10 patients with synchronous liver metastasis (TNM stage IV) were recruited for group B. During the surgical procedure, a 10-mL drainage vein (DV) blood sample was obtained from the DV of the tumor-bearing segment prior to the ligation of the DV. At the same time, a 10-mL peripheral vein (PV) blood sample was collected
RESULTS: Univariate analysis revealed that platelet-derived growth factor AA (PDGFAA) in DV blood (dPDGFAA) (
CONCLUSION: PDGFAA in tumor drainage and HER2 in PV blood may be useful predictive factors for synchronous liver metastasis of colorectal cancer.

Cao ZH, Cheng JL, Zhang Y, et al.
MicroRNA‑375 inhibits oral squamous cell carcinoma cell migration and invasion by targeting platelet‑derived growth factor‑A.
Mol Med Rep. 2017; 15(2):922-928 [PubMed] Related Publications
MicroRNA‑375 (miR‑375) serves an important role in cancer development and growth. However, little is known about the role of miR‑375 in the regulation of oral squamous cell carcinoma (OSCC) metastasis and invasion. The present study measured the expression levels of miR‑375 in Tca8113, UM2, UM1 and CAL‑27 cell lines, using reverse transcription‑quantitative polymerase chain reaction. The results demonstrated that miR‑375 expression levels were significantly reduced in UM1 and CAL‑27 (highly metastatic) compared with Tca8113 and UM2 (less aggressive) OSCC cell lines. Furthermore, it was revealed that overexpression of miR‑375 suppressed the migration and invasion of UM1 cells. Based on a luciferase reporter assay, platelet‑derived growth factor‑A (PDGF‑A) was identified as a direct target gene of miR‑375. Additionally, overexpression of PDGF‑A significantly reversed the effect of miR‑375 on cell migration and invasion in UM1 cells. These data demonstrated that miR‑375 suppressed OSCC cell migration and invasion by targeting PDGF‑A, which may be a potential therapeutic target for the treatment of OSCC.

Watts TL, Cui R, Szaniszlo P, et al.
PDGF-AA mediates mesenchymal stromal cell chemotaxis to the head and neck squamous cell carcinoma tumor microenvironment.
J Transl Med. 2016; 14(1):337 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The robust desmoplasia associated with head and neck squamous cell carcinoma (HNSCC) suggests that the tumor microenvironment may be an important component in the pathophysiology of this cancer. Moreover, the high recurrence rate and poor clinical response to chemotherapy and radiation treatment further underscores that the non-cancerous cells of the microenvironment, such as mesenchymal stromal cells (MSCs), cancer associated fibroblasts (CAFs), and pericytes, may be important in the pathophysiology of HNSCC.
METHODS: Confocal microscopy and immunohistomchemistry approaches were used to identify MSCs tumor microenvironment from patients with oral cavity and oral pharyngeal squamous cell carcinoma (SCC). In vitro Boyden chamber assays and multiplex magnetic bead assays were used to measure MSC chemotaxis and to identify the chemokines secreted by JHU-011, -012, -019, three cells lines derived from patients with oral pharyngeal SCC.
RESULTS: We show here that MSCs reside in the tumor microenvironment of patients with oral cavity and oral pharyngeal SCC and are recruited via paracrine mediated tumor cell secretion of (platelet derived growth factor) PDGF-AA. The MSC markers CD90
CONCLUSIONS: Tumor microenvironment expression of PDGFR-α has been shown to correlate with a worse prognosis in patients with prostate, breast, ovarian, non-small cell lung cancer and osteosarcoma. This is the first evidence that a similar signaling paradigm may be present in HNSCC. PDGFR-α inhibitors have not been studied as adjunctive treatment options in the management of HNSCC and may prove to be an important driver of the malignant phenotype in this setting.

Zhang L, Zhang W, Li Y, et al.
SHP-2-upregulated ZEB1 is important for PDGFRα-driven glioma epithelial-mesenchymal transition and invasion in mice and humans.
Oncogene. 2016; 35(43):5641-5652 [PubMed] Free Access to Full Article Related Publications
Gliomas are highly malignant brain tumors that are highly invasive and resistant to conventional therapy. Receptor tyrosine kinases (RTKs) such as PDGFRα (platelet-derived growth factor receptor-α), which show frequent aberrant activation in gliomas, are associated with a process of epithelial-mesenchymal transition (EMT), a cellular alteration that confers a more invasive and drug-resistant phenotype. Although this phenomenon is well documented in human cancers, the processes by which RTKs including PDGFRα mediate EMT are largely unknown. Here, we report that SHP-2 (encoded by PTPN11) upregulates an EMT inducer, ZEB1, to mediate PDGFRα-driven glioma EMT, invasion and growth in glioma cell lines and patient-derived glioma stem cells (GSCs) using cell culture and orthotopic xenograft models. ZEB1 and activated PDGFRα were coexpressed in invasive regions of mouse glioma xenografts and clinical glioma specimens. Glioma patients with high levels of both phospho-PDGFRα (p-PDGFRα) and ZEB1 had significantly shorter overall survival compared with those with low expression of p-PDGFRα and ZEB1. Knockdown of ZEB1 inhibited PDGFA/PDGFRα-stimulated glioma EMT, tumor growth and invasion in glioma cell lines and patient-derived GSCs. PDGFRα mutant deficient of SHP2 binding (PDGFRα-F720) or phosphoinositide 3-kinase (PI3K) binding (PDGFRα-F731/42), knockdown of SHP2 or treatments of pharmacological inhibitor for PDGFRα-signaling effectors attenuated PDGFA/PDGFRα-stimulated ZEB1 expression, cell migration and GSC proliferation. Importantly, SHP-2 acts together with PI3K/AKT to regulate a ZEB1-miR-200 feedback loop in PDGFRα-driven gliomas. Taken together, our findings uncover a new pathway in which ZEB1 functions as a key regulator for PDGFRα-driven glioma EMT, invasiveness and growth, suggesting that ZEB1 is a promising therapeutic target for treating gliomas with high PDGFRα activation.

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