ITGB4

Gene Summary

Gene:ITGB4; integrin subunit beta 4
Aliases: CD104, GP150
Location:17q25.1
Summary:Integrins are heterodimers comprised of alpha and beta subunits, that are noncovalently associated transmembrane glycoprotein receptors. Different combinations of alpha and beta polypeptides form complexes that vary in their ligand-binding specificities. Integrins mediate cell-matrix or cell-cell adhesion, and transduced signals that regulate gene expression and cell growth. This gene encodes the integrin beta 4 subunit, a receptor for the laminins. This subunit tends to associate with alpha 6 subunit and is likely to play a pivotal role in the biology of invasive carcinoma. Mutations in this gene are associated with epidermolysis bullosa with pyloric atresia. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:integrin beta-4
Source:NCBIAccessed: 11 March, 2017

Ontology:

What does this gene/protein do?
Show (19)
Pathways:What pathways are this gene/protein implicaed in?
Show (4)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Gene Expression
  • Up-Regulation
  • Biomarkers, Tumor
  • Tongue Neoplasms
  • Neoplasm Metastasis
  • Protein Biosynthesis
  • Cancer Gene Expression Regulation
  • Tumor Burden
  • Breast Cancer
  • MicroRNAs
  • Cell Adhesion
  • Urokinase-Type Plasminogen Activator
  • Bladder Cancer
  • Single Nucleotide Polymorphism
  • siRNA
  • Pancreatic Cancer
  • Binding Sites
  • Apoptosis
  • Signal Transduction
  • Survival Rate
  • Young Adult
  • RTPCR
  • DNA Sequence Analysis
  • Tissue Plasminogen Activator
  • Oligonucleotide Array Sequence Analysis
  • Transcription Factor AP-1
  • Integrin alpha3
  • Transcription Factors
  • Integrin beta4
  • RNA Interference
  • src-Family Kinases
  • Down-Regulation
  • Oral Cavity Cancer
  • Genetic Predisposition
  • Cell Movement
  • Vimentin
  • Gene Expression Profiling
  • Neoplasm Invasiveness
  • Cell Proliferation
  • Chromosome 17
  • Squamous Cell Carcinoma
  • Lymphatic Metastasis
Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

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: ITGB4 (cancer-related)

Kim CW, Roh SA, Tak KH, et al.
ZKSCAN3 Facilitates Liver Metastasis of Colorectal Cancer Associated with CEA-expressing Tumor.
Anticancer Res. 2016; 36(5):2397-406 [PubMed] Related Publications
AIM: Zinc finger with KRAB and SCAN domain 3 (ZKSCAN3) is overexpressed in invasive colorectal cancer (CRC) cells and regulates the expression of several genes favoring tumor progression, including vascular endothelial growth factor (VEGF) and integrin β4. We evaluated the association of ZKSCAN3 and colorectal cancer liver metastasis (CLM) to determine whether it is related to invasive signaling pathways.
MATERIALS AND METHODS: The ratios of expression by primary tumor to normal tissue and metastatic tumor to normal tissue were compared between ZKSCAN3-overexpressing and underexpressing primary tumor groups.
RESULTS: In terms of CLM, the ZKSCAN3 overexpression was positively correlated with carcinoembryonic antigen (CEA), VEGF, and AKT expression. The protein-expression analysis showed that ZKSCAN-specific siRNA knockdown reduced CEA expression in LoVo and LS174T CRC cells. Matrigel invasion by ZKSCAN3-overexpressing HCT116 cells was increased when examined on CEA-coated filters compared with phosphate-buffered saline-treated controls. Additionally, matrix metalloproteinase 9 (MMP9) expression was greater in cells with reference allele (GG) than substitution allele (CC) for ZKSCAN3 rs733743 (p=0.032). ZKSCAN3 protein expression of the high serum CEA group was increased in hepatic metastatic tissue compared with the primary tumor tissue, while in the group with normal serum CEA it decreased or was similar. Reference ZKSCAN3 alleles were correlated with male dominance, a family history of malignancy, high serum CEA concentration and stage IV CRC in 450 patients with sporadic CRC. In conclusion, ZKSCAN3 appears to promote colorectal tumor progression and invasion. ZKSCAN3 may facilitate hepatic metastasis of CRC associated with CEA particularly in cases with CEA-producing tumor.

Li P, Silvis MR, Honaker Y, et al.
αE-catenin inhibits a Src-YAP1 oncogenic module that couples tyrosine kinases and the effector of Hippo signaling pathway.
Genes Dev. 2016; 30(7):798-811 [PubMed] Free Access to Full Article Related Publications
Cell-cell adhesion protein αE-catenin inhibits skin squamous cell carcinoma (SCC) development; however, the mechanisms responsible for this function are not completely understood. We report here that αE-catenin inhibits β4 integrin-mediated activation of SRC tyrosine kinase.SRCis the first discovered oncogene, but the protein substrate critical for SRC-mediated transformation has not been identified. We found that YAP1, the pivotal effector of the Hippo signaling pathway, is a direct SRC phosphorylation target, and YAP1 phosphorylation at three sites in its transcription activation domain is necessary for SRC-YAP1-mediated transformation. We uncovered a marked increase in this YAP1 phosphorylation in human and mouse SCC tumors with low/negative expression of αE-catenin. We demonstrate that the tumor suppressor function of αE-catenin involves negative regulation of the β4 integrin-SRC signaling pathway and that SRC-mediated phosphorylation and activation of YAP1 are an alternative to the canonical Hippo signaling pathway that directly connect oncogenic tyrosine kinase signaling with YAP1.

Leng C, Zhang ZG, Chen WX, et al.
An integrin beta4-EGFR unit promotes hepatocellular carcinoma lung metastases by enhancing anchorage independence through activation of FAK-AKT pathway.
Cancer Lett. 2016; 376(1):188-96 [PubMed] Related Publications
Anoikis, a form of programmed cell death, occurs when the cells are detached from the appropriate extracellular matrix. Anoikis resistance or anchorage independence is necessary for distant metastases of cancer. The mechanisms by which hepatocellular carcinoma (HCC) cells become resistant to anoikis are not fully understood. Integrin beta4 (ITGB4, also known as CD104) is associated with progression of many human cancers. In this study, we demonstrate that ITGB4 is over-expressed in HCC tissues and aggressive HCC cell lines. To explore the role of ITGB4 in HCC, we inhibited its expression using small interfering RNA in two HCC cell lines: HCCLM3 and HLF. We show that knockdown of ITGB4 significantly enhanced susceptibility to anoikis through inhibition of AKT/PKB signaling. Moreover, ITGB4 interacts with epidermal growth factor receptor (EGFR) in a ligand independent manner. Inactivation of EGFR inhibits the anchorage independence and AKT pathway promoted by ITGB4. Further investigation proved that the ITGB4-EGFR unit triggers the focal adhesion kinase (FAK) to activate the AKT signaling pathway. Finally, we demonstrate that over-expression of ITGB4 is positively associated with tumor growth and lung metastases of HCC in vivo. Collectively, we demonstrate for the first time that ITGB4 is overexpressed in HCC tissues and promotes metastases of HCC by conferring anchorage independence through EGFR-dependent FAK-AKT activation.

Sun Y, Yang X, Liu M, Tang H
B4GALT3 up-regulation by miR-27a contributes to the oncogenic activity in human cervical cancer cells.
Cancer Lett. 2016; 375(2):284-92 [PubMed] Related Publications
β-1,4-Galactosyltransferase III (B4GALT3) is an enzyme responsible for the generation of poly-N-acetyllactosamine and is involved in tumorigenesis. However, B4GALT3-dysregulation and its role in cervical cancer cells are unknown. Herein, we found that B4GALT3 was upregulated in cervical cancer tissues compared to adjacent non-tumor tissues. B4GALT3-overexpression promoted, whereas B4GALT3-knockdown suppressed the cellular migration, invasion and EMT of HeLa and C33A cervical cancer cells. To explore the mechanism of dysregulation, B4GALT3 was predicted to be a target of miR-27a. EGFP and pGL3-promoter reporter assay showed miR-27a binds to B4GALT3 3'UTR region but enhanced its expression. RT-qPCR showed miR-27a was also upregulated and presented positive correlation with B4GALT3-expression in cervical cancer tissues. miR-27a-overexpression promoted, but blocking-miR-27a repressed these malignancies in HeLa and C33A cells. Furthermore, shR-B4GALT3 counteracted the promotion of malignancies induced by miR-27a, suggesting miR-27a upregulates B4GALT3 to enhance tumorigenic activities. In addition, we found that B4GALT3 significantly enhances β1-integrin stability, thus mediating promotion of B4GALT3 on malignancy in cervical cancer cells. Altogether, our findings evidenced that B4GALT3 upregulated by miR-27a contributes to the tumorigenic activities by β1-integrin pathway and might provide potential biomarkers for cervical cancer.

Dmello C, Sawant S, Alam H, et al.
Vimentin-mediated regulation of cell motility through modulation of beta4 integrin protein levels in oral tumor derived cells.
Int J Biochem Cell Biol. 2016; 70:161-72 [PubMed] Related Publications
Vimentin expression correlates well with migratory and invasive potential of the carcinoma cells. The molecular mechanism by which vimentin regulates cell motility is not yet clear. Here, we addressed this issue by depleting vimentin in oral squamous cell carcinoma derived cell line. Vimentin knockdown cells showed enhanced adhesion and spreading to laminin-5. However, we found that they were less invasive as compared to the vector control cells. In addition, signaling associated with adhesion behavior of the cell was increased in vimentin knockdown clones. These findings suggest that the normal function of β4 integrin as mechanical adhesive device is enhanced upon vimentin downregulation. As a proof of principle, the compromised invasive potential of vimentin depleted cells could be rescued upon blocking with β4 integrin adhesion-blocking (ASC-8) antibody or downregulation of β4 integrin in vimentin knockdown background. Interestingly, plectin which associates with α6β4 integrin in the hemidesmosomes, was also found to be upregulated in vimentin knockdown clones. Furthermore, experiments on lysosome and proteasome inhibition revealed that perhaps vimentin regulates the turnover of β4 integrin and plectin. Moreover, an inverse association was observed between vimentin expression and β4 integrin in oral squamous cell carcinoma (OSCC). Collectively, our results show a novel role of vimentin in modulating cell motility by destabilizing β4 integrin-mediated adhesive interactions. Further, vimentin-β4 integrin together may prove to be useful markers for prognostication of human oral cancer.

Hoshino A, Costa-Silva B, Shen TL, et al.
Tumour exosome integrins determine organotropic metastasis.
Nature. 2015; 527(7578):329-35 [PubMed] Free Access to Full Article Related Publications
Ever since Stephen Paget's 1889 hypothesis, metastatic organotropism has remained one of cancer's greatest mysteries. Here we demonstrate that exosomes from mouse and human lung-, liver- and brain-tropic tumour cells fuse preferentially with resident cells at their predicted destination, namely lung fibroblasts and epithelial cells, liver Kupffer cells and brain endothelial cells. We show that tumour-derived exosomes uptaken by organ-specific cells prepare the pre-metastatic niche. Treatment with exosomes from lung-tropic models redirected the metastasis of bone-tropic tumour cells. Exosome proteomics revealed distinct integrin expression patterns, in which the exosomal integrins α6β4 and α6β1 were associated with lung metastasis, while exosomal integrin αvβ5 was linked to liver metastasis. Targeting the integrins α6β4 and αvβ5 decreased exosome uptake, as well as lung and liver metastasis, respectively. We demonstrate that exosome integrin uptake by resident cells activates Src phosphorylation and pro-inflammatory S100 gene expression. Finally, our clinical data indicate that exosomal integrins could be used to predict organ-specific metastasis.

Knyazev EN, Nyushko KM, Alekseev BY, et al.
Suppression of ITGB4 Gene Expression in PC-3 Cells with Short Interfering RNA Induces Changes in the Expression of β-Integrins Associated with RGD-Receptors.
Bull Exp Biol Med. 2015; 159(4):541-5 [PubMed] Related Publications
We studied the effect of transfection of PC-3 prostate cancer cells with a plasmid encoding shRNA complimentary to a fragment of integrin β4 (ITGB4). The results attest to considerable changes in the transcriptome of transfected cells. For instance, compensatory changes in the expression of integrin family genes were found.

Buas MF, Rho JH, Chai X, et al.
Candidate early detection protein biomarkers for ER+/PR+ invasive ductal breast carcinoma identified using pre-clinical plasma from the WHI observational study.
Breast Cancer Res Treat. 2015; 153(2):445-54 [PubMed] Free Access to Full Article Related Publications
Estrogen receptor (ER)-positive/progesterone receptor (PR)-positive invasive ductal carcinoma accounts for ~45 % of invasive breast cancer (BC) diagnoses in the U.S. Despite reductions in BC mortality attributable to mammography screening and adjuvant hormonal therapy, an important challenge remains the development of clinically useful blood-based biomarkers for risk assessment and early detection. The objective of this study was to identify novel protein markers for ER+/PR+ ductal BC. A nested case-control study was conducted within the Women's Health Initiative observational study. Pre-clinical plasma specimens, collected up to 12.5 months before diagnosis from 121 cases and 121 matched controls, were equally divided into training and testing sets and interrogated using a customized antibody array targeting >2000 proteins. Statistically significant differences (P < 0.05) in matched case versus control signals were observed for 39 candidates in both training and testing sets, and four markers (CSF2, RYBP, TFRC, ITGB4) remained significant after Bonferroni correction (P < 2.03 × 10(-5)). A multivariate modeling procedure based on elastic net regression with Monte Carlo cross-validation achieved an estimated AUC of 0.75 (SD 0.06). Most candidates did not overlap with those described previously for triple-negative BC, suggesting sub-type specificity. Gene set enrichment analyses identified two GO gene sets as upregulated in cases-microtubule cytoskeleton and response to hormone stimulus (P < 0.05, q < 0.25). This study has identified a pool of novel candidate plasma protein biomarkers for ER+/PR+ ductal BC using pre-diagnostic biospecimens. Further validation studies are needed to confirm these candidates and assess their potential clinical utility for BC risk assessment/early detection.

Jun KH, Lee JE, Kim SH, et al.
Clinicopathological significance of N-cadherin and VEGF in advanced gastric cancer brain metastasis and the effects of metformin in preclinical models.
Oncol Rep. 2015; 34(4):2047-53 [PubMed] Related Publications
Gastric cancer is the second most common cause of cancer-related death worldwide. Although brain metastasis is a rare complication of gastric cancer, no standard therapy for gastric cancer brain metastasis has been established. We attempted to identify biological markers that predict brain metastasis, and investigated how to modulate such markers. A case-control study of patients newly diagnosed with gastric cancer who had developed brain metastasis during follow-up, was conducted. These patients were compared with patients who had advanced gastric cancer but no evidence of brain metastasis. Immunohistochemistry was used to analyze the expression of E-cadherin, N-cadherin, MSS1, claudin-3, claudin-4, Glut1, clusterin, ITGB4, vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR) and p53. The expression of VEGF tended to be higher in the case group (33.3 vs. 0%, p=0.055). Median survival was significantly correlated with vascular invasion (12 vs. 33 months, p=0.008) and N-cadherin expression (36 vs. 12 months, p=0.027). We also investigated the effects of metformin in tumor-bearing mouse models. VEGF expression was decreased and E-cadherin increased in the metformin‑treated group when compared with the control group. The expression of the mesenchymal marker MMP9 was decreased in the metformin-treated group. Brain metastasis of advanced gastric cancer was associated with the expression of VEGF. Metformin treatment may be useful for modulating the metastatic capacity by reducing VEGF expression and blocking epithelial-to-mesenchymal transition.

Caldeira J, Figueiredo J, Brás-Pereira C, et al.
E-cadherin-defective gastric cancer cells depend on Laminin to survive and invade.
Hum Mol Genet. 2015; 24(20):5891-900 [PubMed] Free Access to Full Article Related Publications
Epithelial-cadherin (Ecad) deregulation affects cell-cell adhesion and results in increased invasiveness of distinct human carcinomas. In gastric cancer, loss of Ecad expression is a common event and is associated with disease aggressiveness and poor prognosis. However, the molecular mechanisms underlying the invasive process associated to Ecad dysfunction are far from understood. We hypothesized that deregulation of cell-matrix interactions could play an important role during this process. Thus, we focussed on LM-332, which is a major matrix component, and in Ecad/LM-332 crosstalk in the process of Ecad-dependent invasion. To verify whether matrix deregulation was triggered by Ecad loss, we used the Drosophila model. To dissect the key molecules involved and unveil their functional significance, we used gastric cancer cell lines. The relevance of this relationship was then confirmed in human primary tumours. In vivo, Ecad knockdown induced apoptosis; nonetheless, at the invasive front, cells ectopically expressed Laminin A and βPS integrin. In vitro, we demonstrated that, in two different gastric cancer cell models, Ecad-defective cells overexpressed Laminin γ2 (LM-γ2), β1 and β4 integrin, when compared with Ecad-competent ones. We showed that LM-γ2 silencing impaired invasion and enhanced cell death, most likely via pSrc and pAkt reduction, and JNK activation. In human gastric carcinomas, we found a concomitant decrease in Ecad and increase in LM-γ2. This is the first evidence that ectopic Laminin expression depends on Ecad loss and allows Ecad-dysfunctional cells to survive and invade. This opens new avenues for using LM-γ2 signalling regulators as molecular targets to impair gastric cancer progression.

Lee JG, Ahn JH, Jin Kim T, et al.
Mutant p53 promotes ovarian cancer cell adhesion to mesothelial cells via integrin β4 and Akt signals.
Sci Rep. 2015; 5:12642 [PubMed] Free Access to Full Article Related Publications
Missense mutations in the TP53 gene resulting in the accumulation of mutant proteins are extremely common in advanced ovarian cancer, which is characterised by peritoneal metastasis. Attachment of cancer cells to the peritoneal mesothelium is regarded as an initial, key step for the metastatic spread of ovarian cancer. In the present study, we investigated the possible role of a p53 mutant in the mesothelial adhesion of ovarian cancer cells. We found that OVCAR-3 cells with the R248 TP53 mutation (p53(R248)) were more adhesive to mesothelial Met5A cells than were A2780 cells expressing wild-type p53. In addition, ectopic expression of p53(R248) in p53-null SKOV-3 cells significantly increased adhesion to Met5A cells. Knockdown of mutant p53 significantly compromised p53(R248)-induced cell adhesion to Met5A cells. Microarray analysis revealed that several adhesion-related genes, including integrin β4, were markedly up-regulated, and certain signalling pathways, including PI3K/Akt, were activated in p53(R248) transfectants of SKOV-3 cells. Inhibition of integrin β4 and Akt signalling using blocking antibody and the inhibitor LY294002, respectively, significantly attenuated p53(R248)-mediated ovarian cancer-mesothelial adhesion. These data suggest that the p53(R248) mutant endows ovarian cancer cells with increased adhesiveness and that integrin β4 and Akt signalling are associated with the mutation-enhanced ovarian cancer-mesothelial cell adhesion.

Ding S, Chen G, Zhang W, et al.
MRC-5 fibroblast-conditioned medium influences multiple pathways regulating invasion, migration, proliferation, and apoptosis in hepatocellular carcinoma.
J Transl Med. 2015; 13:237 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Carcinoma associated fibroblasts (CAFs), an important component of tumor microenvironment, are capable of enhancing tumor cells invasion and migration through initiation of epithelial-mesenchymal transition (EMT). MRC-5 fibroblasts are one of the CAFs expressing alpha-smooth muscle actin. It is ascertained that medium conditioned by MRC-5 fibroblasts stimulate motility and invasion of breast cancer cells. However, its role in hepatocellular carcinoma (HCC) is less clear. The aim of our study was to investigate the effect of MRC-5-CM on HCC and explore the underlying mechanisms.
METHODS AND RESULTS: Using a combination of techniques, the role of MRC-5-CM in HCC was evaluated. We determined that MRC-5-CM induced the non-classical EMT in Bel-7402 and MHCC-LM3 cell lines. Initiation of the non-classical EMT was mainly via quintessential redistribution of α-, β- and γ-catenin, P120 catenin, E-cadherin, and N-cadherin, rather than up-regulation of typical EMT-related transcription factors (i.e., Snail, Twist1, ZEB-1 and ZEB2). We also found that MRC-5-CM potentiated both the migration and invasion of Bel-7402 and MHCC-LM3 cells in mesenchymal movement mode through activation of the α6, β3, β4, β7 integrin/FAK pathway and upregulation of MMP2. The flow cytometric analysis showed that MRC-5-CM induced G1 phase arrest in Bel-7402 cells with a concomitant reduction of S phase cells. In contrast, MRC-5-CM induced S phase arrest in MHCC-LM3 cells with a concomitant reduction of cells in the G2/M phase. MRC-5-CM also inhibited apoptosis in Bel-7402 cells while inducing apoptosis in MHCC-LM3 cells.
CONCLUSION: Collectively, MRC-5-CM promoted HCC cell motility and invasiveness through initiation of the non-classical EMT, including redistribution of α-, β- and γ-catenin, P120 catenin, E-cadherin, and N-cadherin, activation of the integrin/FAK pathway, and upregulation of MMP2. Hence, MRC-5-CM exerted distinct roles in Bel-7402 and MHCC-LM3 cell viability by regulating cyclins, cyclin dependent kinases (CDKs), CDK inhibitors (CKIs), Bcl-2 family proteins and other unknown mechanosensors.

Tang K, Cai Y, Joshi S, et al.
Convergence of eicosanoid and integrin biology: 12-lipoxygenase seeks a partner.
Mol Cancer. 2015; 14:111 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Integrins and enzymes of the eicosanoid pathway are both well-established contributors to cancer. However, this is the first report of the interdependence of the two signaling systems. In a screen for proteins that interacted with, and thereby potentially regulated, the human platelet-type 12-lipoxygenase (12-LOX, ALOX12), we identified the integrin β4 (ITGB4).
METHODS: Using a cultured mammalian cell model, we have demonstrated that ITGB4 stimulation leads to recruitment of 12-LOX from the cytosol to the membrane where it physically interacts with the integrin to become enzymatically active to produce 12(S)-HETE, a known bioactive lipid metabolite that regulates numerous cancer phenotypes.
RESULTS: The net effect of the interaction was the prevention of cell death in response to starvation. Additionally, regulation of β4-mediated, EGF-stimulated invasion was shown to be dependent on 12-LOX, and downstream Erk signaling in response to ITGB4 activation also required 12-LOX.
CONCLUSIONS: This is the first report of an enzyme of the eicosanoid pathway being recruited to and regulated by activated β4 integrin. Integrin β4 has recently been shown to induce expansion of prostate tumor progenitors and there is a strong correlation between stage/grade of prostate cancer and 12-LOX expression. The 12-LOX enzymatic product, 12(S)-HETE, regulates angiogenesis and cell migration in many cancer types. Therefore, disruption of integrin β4-12LOX interaction could reduce the pro-inflammatory oncogenic activity of 12-LOX. This report on the consequences of 12-LOX and ITGB4 interaction sets a precedent for the linkage of integrin and eicosanoid biology through direct protein-protein association.

Lee HJ, Lee JS, Hwang SJ, Lee HY
Insulin-like growth factor binding protein-3 inhibits cell adhesion via suppression of integrin β4 expression.
Oncotarget. 2015; 6(17):15150-63 [PubMed] Free Access to Full Article Related Publications
We previously reported that IGF binding protein-3 (IGFBP-3), a major IGF-binding protein in human serum, regulates angiogenic activities of human head and neck squamous cell carcinoma (HNSCC) cells and human umbilical vein endothelial cells (HUVECs) through IGF-dependent and IGF-independent mechanisms. However, the role of IGFBP-3 in cell adhesion is largely unknown. We demonstrate here that IGFBP-3 inhibits the adhesion of HNSCC cells and HUVECs to the extracellular matrix (ECM). IGFBP-3 reduced transcription of a variety of integrins, especially integrin β4, and suppressed phosphorylation of focal adhesion kinase (FAK) and Src in these cells through both IGF-dependent and IGF-independent pathways. IGFBP-3 was found to suppress the transcription of c-fos and c-jun and the activity of AP1 transcription factor. The regulatory effect of IGFBP-3 on integrin β4 transcription was attenuated by blocking c-jun and c-fos gene expression via siRNA transfection. Taken together, our data show that IGFBP-3 has IGF-dependent and -independent inhibitory effects on intracellular adhesion signaling in HNSCC and HUVECs through its ability to block c-jun and c-fos transcription and thus AP-1-mediated integrin β4 transcription. Collectively, our data suggest that IGFPB-3 may be an effective cancer therapeutic agent by blocking integrin-mediated adhesive activity of tumor and vascular endothelial cells.

Du J, Hong S, Dong L, et al.
Dynamic Sialylation in Transforming Growth Factor-β (TGF-β)-induced Epithelial to Mesenchymal Transition.
J Biol Chem. 2015; 290(19):12000-13 [PubMed] Free Access to Full Article Related Publications
Epithelial-mesenchymal transition (EMT) is a fundamental process in embryonic development and organ formation. Aberrant regulation of EMT often leads to tumor progression. Changes in cell surface sialylation have recently been implicated in mediating EMT. Herein we report the visualization of dynamic changes of sialylation and glycoproteomic analysis of newly synthesized sialylated proteins in EMT by metabolic labeling of sialylated glycans with azides, followed by click labeling with fluorophores or affinity tags. We discovered that sialylation was down-regulated during EMT but then reverted and up-regulated in the mesenchymal state after EMT, accompanied by mRNA expression level changes of genes involved in the sialic acid biosynthesis. Quantitative proteomic analysis identified a list of sialylated proteins whose biosynthesis was dynamically regulated during EMT. Sialylation of cell surface adherent receptor integrin β4 was found to be down-regulated, which may regulate integrin functions during EMT. Furthermore, a global sialylation inhibitor was used to probe the functional role of sialylation during EMT. We found that inhibition of sialylation promoted EMT. Taken together, our findings suggest the important role of sialylation in regulating EMT and imply its possible function in related pathophysiological events, such as cancer metastasis.

Masugi Y, Yamazaki K, Emoto K, et al.
Upregulation of integrin β4 promotes epithelial-mesenchymal transition and is a novel prognostic marker in pancreatic ductal adenocarcinoma.
Lab Invest. 2015; 95(3):308-19 [PubMed] Related Publications
Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive and often lethal malignant tumor. Several studies have shown that epithelial-mesenchymal transition (EMT) is frequently observed in clinical samples of PDA and is related to high metastatic rates and poor outcomes. To identify candidate molecules regulating EMT in PDA, we previously used cDNA microarray analysis and identified integrin β4 (ITGB4) as one of the genes upregulated in high-EMT xenografts derived from PDA patients. The aim of the current study was to clarify the clinicopathological and functional significance of ITGB4 overexpression in PDA. ITGB4 upregulation in high-EMT xenografts was confirmed by immunohistochemistry. Immunohistochemical analyses of 134 surgically resected PDA cases revealed intratumoral heterogeneity with respect to ITGB4 expression and showed that cancer cells undergoing EMT often display strong diffuse ITGB4 expression. High levels of ITGB4 expression were significantly correlated with the hallmarks of EMT (solitary cell infiltration, reduced E-cadherin expression, and increased vimentin expression), with high tumor grade, and with the presence of lymph node metastasis, and showed an independent prognostic effect. Immunocytochemical analyses of PDA cell lines revealed that localization of ITGB4 changed from regions of cell-cell contact to diffuse cytoplasm and cell edges with occasional localization in filopodia during EMT. Knockdown of ITGB4 reduced the migratory and invasive ability of PDA cells. Overexpression of ITGB4 promoted cell scattering and cell motility in combination with downregulation of E-cadherin and upregulation of vimentin expression. In conclusion, we elucidated the prognostic and clinicopathological significance of ITGB4 overexpression in PDA and also the potential role for ITGB4 in the regulation of cancer invasion and EMT.

Li XL, Lu X, Parvathaneni S, et al.
Identification of RECQ1-regulated transcriptome uncovers a role of RECQ1 in regulation of cancer cell migration and invasion.
Cell Cycle. 2014; 13(15):2431-45 [PubMed] Free Access to Full Article Related Publications
The RECQ protein family of helicases has critical roles in protecting and stabilizing the genome. Three of the 5 known members of the human RecQ family are genetically linked with cancer susceptibility syndromes, but the association of the most abundant human RecQ homolog, RECQ1, with cellular transformation is yet unclear. RECQ1 is overexpressed in a variety of human cancers, indicating oncogenic functions. Here, we assessed genome-wide changes in gene expression upon knockdown of RECQ1 in HeLa and MDA-MB-231 cells. Pathway analysis suggested that RECQ1 enhances the expression of multiple genes that play key roles in cell migration, invasion, and metastasis, including EZR, ITGA2, ITGA3, ITGB4, SMAD3, and TGFBR2. Consistent with these results, silencing RECQ1 significantly reduced cell migration and invasion. In comparison to genome-wide annotated promoter regions, the promoters of genes downregulated upon RECQ1 silencing were significantly enriched for a potential G4 DNA forming sequence motif. Chromatin immunoprecipitation assays demonstrated binding of RECQ1 to the G4 motifs in the promoters of select genes downregulated upon RECQ1 silencing. In breast cancer patients, the expression of a subset of RECQ1-activated genes positively correlated with RECQ1 expression. Moreover, high RECQ1 expression was associated with poor prognosis in breast cancer. Collectively, our findings identify a novel function of RECQ1 in gene regulation and indicate that RECQ1 contributes to tumor development and progression, in part, by regulating the expression of key genes that promote cancer cell migration, invasion and metastasis.

Song X, Zhong H, Zhou J, et al.
Association between polymorphisms of microRNA-binding sites in integrin genes and gastric cancer in Chinese Han population.
Tumour Biol. 2015; 36(4):2785-92 [PubMed] Related Publications
Highly elevated expression of integrin has been observed in a variety of malignant tumors. Single nucleotide polymorphisms (SNPs) in the microRNA-binding sites in the 3' UTR region of target genes may result in the level change of target gene expression and subsequently susceptible to diseases, including cancer. In this study, we aimed to investigate the association between polymorphisms of microRNA-binding sites of integrin genes and gastric cancer (GC) in Chinese Han population. Five SNPs of the microRNA-binding sites in the 3' UTR region of integrin genes (rs1062484 C/T in ITGA3, rs17664 A/G in ITGA6, rs3809865 A/T in ITGB3, rs743554 C/T in ITGB4, and rs2675 A/C in ITGB5) were studied using high resolution melting (HRM) analysis in 1000 GC patients and 1000 unrelated controls. The polymorphism of SNP rs2675 was associated with susceptibility of GC [odds ratio (OR) = 0.52, 95% confidence interval (CI) = 0.28-0.97, P = 0.028]. In addition, genotype AA of rs2675 and genotype GG of rs17664 were associated with a lower chance of GC at stage 1b [OR = 0.39 (0.18-0.85), P = 0.009; and OR = 0.37 (0.17-0.78), P = 0.004, respectively]; also, the frequency of allele G of rs17664 was associated with a lower chance of stage 1b tumor [OR = 0.50 (0.26-0.95), P = 0.021]. Furthermore, the frequency of genotype AA and allele A of rs3809865 were associated with a higher risk of stage 4 GC [OR = 1.85 (1.11-3.09), P = 0.012; and OR = 1.52 (0.99-2.33), P = 0.043, respectively]. For rs17664, GG genotype and allele G appeared to be associated with a higher risk with GC with lymphatic metastasis 3b [OR = 1.76 (1.00-3.11), P = 0.036; and OR = 1.64 (0.98-2.75), P = 0.048, respectively]. Our data suggest that polymorphisms of the microRNA-binding sites in the 3' UTR region of integrin are associated with GC susceptibility (rs2675), tumor stage (rs2675, rs17664, and rs3809865), and lymphatic metastasis (rs17664) in Chinese Han population.

Zubor P, Hatok J, Moricova P, et al.
Gene expression abnormalities in histologically normal breast epithelium from patients with luminal type of breast cancer.
Mol Biol Rep. 2015; 42(5):977-88 [PubMed] Related Publications
The gene expression profile of breast cancer has been described as a great breakthrough on the way to comprehend differences in cancer origin, behavior and therapy. However, gene expression profile in histologically normal epithelium (HNEpi) which could harbor genetic abnormalities predisposing breast tissue to develop malignancy was minor scope for scientists in the past. Thus, we aimed to analyze gene expressions in HNEpi and breast cancer tissue (BCTis) in order to establish its value as potential diagnostic marker for cancer development. We evaluated a panel of disease-specific genes in luminal type (A/B) of breast cancer and tumor surrounding HNEpi by qRT-PCR Array in 32 microdissected samples. There was 20.2 and 2.4% deregulation rate in genes with at least 2-fold or 5-fold over-expression between luminal (A/B) type breast carcinomas and tumor surrounding HNEpi, respectively. The high-grade luminal carcinomas showed higher number of deregulated genes compared to low-grade cases (50.6 vs. 23.8% with at least 2-fold deregulation rate). The main overexpressed genes in HNEpi were KLK5, SCGB1D2, GSN, EGFR and NGFR. The significant differences in gene expression between BCTis and HNEpi samples were revealed for BAG1, C3, CCNA2, CD44, FGF1, FOSL1, ID2, IL6R, NGFB, NGFR, PAPPA, PLAU, SERPINB5, THBS1 and TP53 gene (p < 0.05) and BCL2L2, CTSB, ITGB4, JUN, KIT, KLF5, SCGB1D2, SCGB2A1, SERPINE1 (p < 0.01), and EGFR, GABRP, GSN, MAP2K7 and THBS2 (p < 0.001), and GSN, KLK5 (p < 0.0001). The ontological gene analyses revealed high deregulations in gene group directly associated with breast cancer prognosis and origin.

Madhavan B, Yue S, Galli U, et al.
Combined evaluation of a panel of protein and miRNA serum-exosome biomarkers for pancreatic cancer diagnosis increases sensitivity and specificity.
Int J Cancer. 2015; 136(11):2616-27 [PubMed] Related Publications
Late diagnosis contributes to pancreatic cancer (PaCa) dismal prognosis, urging for reliable, early detection. Serum-exosome protein and/or miRNA markers might be suitable candidates, which we controlled for patients with PaCa. Protein markers were selected according to expression in exosomes of PaCa cell line culture supernatants, but not healthy donors' serum-exosomes. miRNA was selected according to abundant recovery in microarrays of patients with PaCa, but not healthy donors' serum-exosomes and exosome-depleted serum. According to these preselections, serum-exosomes were tested by flow cytometry for the PaCa-initiating cell (PaCIC) markers CD44v6, Tspan8, EpCAM, MET and CD104. Serum-exosomes and exosome-depleted serum was tested for miR-1246, miR-4644, miR-3976 and miR-4306 recovery by qRT-PCR. The majority (95%) of patients with PaCa (131) and patients with nonPa-malignancies reacted with a panel of anti-CD44v6, -Tspan8, -EpCAM and -CD104. Serum-exosomes of healthy donors' and patients with nonmalignant diseases were not reactive. Recovery was tumor grading and staging independent including early stages. The selected miR-1246, miR-4644, miR-3976 and miR-4306 were significantly upregulated in 83% of PaCa serum-exosomes, but rarely in control groups. These miRNA were also elevated in exosome-depleted serum of patients with PaCa, but at a low level. Concomitant evaluation of PaCIC and miRNA serum-exosome marker panels significantly improved sensitivity (1.00, CI: 0.95-1) with a specificity of 0.80 (CI: 0.67-0.90) for PaCa versus all others groups and of 0.93 (CI: 0.81-0.98) excluding nonPa-malignancies. Thus, the concomitant evaluation of PaCIC and PaCa-related miRNA marker panels awaits retrospective analyses of larger cohorts, as it should allow for a highly sensitive, minimally-invasive PaCa diagnostics.

Makarević J, Rutz J, Juengel E, et al.
Amygdalin influences bladder cancer cell adhesion and invasion in vitro.
PLoS One. 2014; 9(10):e110244 [PubMed] Free Access to Full Article Related Publications
The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK) and total and activated focal adhesion kinase (FAK) were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines) may depend upon the cancer cell type.

Mishra DK, Scott KL, Wardwell-Ozgo JM, et al.
Circulating tumor cells from 4D model have less integrin beta 4 expression.
J Surg Res. 2015; 193(2):745-53 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Currently, there is no in vitro or ex vivo model that can isolate circulating tumor cells (CTCs). Recently, we developed a four-dimensional (4D) lung cancer model that allows for the isolation of CTCs. We postulated that these cells have different properties than parental (2D) cells.
MATERIALS AND METHODS: We obtained CTCs by growing A549, H1299, 393P, and 344SQ cell lines on the 4D lung model. The CTCs were functionally characterized in vitro and gene expression of the cell adhesion molecules was compared with respective 2D cells. Integrin beta 4 (ITGB4) was further investigated by stably transfecting the A549 and H1299 cells.
RESULTS: We found that all cell lines produced CTCs, and that CTCs from the 4D model were less adherent to the plastic and have a slower growth rate than respective 2D cells (P < 0.01). Most of the cell adhesion molecules were downregulated (P < 0.05) in CTCs, and ITGB4 was the common molecule, significantly more underexpressed in CTCs from all cell lines than their respective 2D cells. The modulation of ITGB4 led to a differential function of 2D cells.
CONCLUSIONS: CTCs from the 4D model have different transcriptional, translational, and in vitro characteristics than the same cells grown on a petri dish, and these CTCs from the 4D model have the properties of CTCs that are responsible for metastasis.

Piao Z, Hong CS, Jung MR, et al.
Thymosin β4 induces invasion and migration of human colorectal cancer cells through the ILK/AKT/β-catenin signaling pathway.
Biochem Biophys Res Commun. 2014; 452(3):858-64 [PubMed] Related Publications
Thymosin β4 (Tβ4) is a 43-amino-acid peptide involved in many biological processes. However, the precise molecular signaling mechanism(s) of Tβ4 in cell invasion and migration remain unclear. In this study, we show that Tβ4 was significantly overexpressed in colorectal cancer tissues compared to adjacent normal tissues and high levels of Tβ4 were correlated with stage of colorectal cancer, and that Tβ4 expression was associated with morphogenesis and EMT. Tβ4-upregulated cancer cells showed increased adhesion, invasion and migration activity, whereas Tβ4-downregulated cells showed decreased activities. We also demonstrated that Tβ4 interacts with ILK, which promoted the phosphorylation and activation of AKT, the phosphorylation and inactivation of GSK3β, the expression and nuclear localization of β-catenin, and integrin receptor activation. These results suggest that Tβ4 is an important regulator of the ILK/AKT/β-catenin/Integrin signaling cascade to induce cell invasion and migration in colorectal cancer cells, and is a potential target for cancer treatment.

Wang L, Feng Z, Wu H, et al.
Melanoma differentiation-associated gene-7/interleukin-24 as a potential prognostic biomarker and second primary malignancy indicator in head and neck squamous cell carcinoma patients.
Tumour Biol. 2014; 35(11):10977-85 [PubMed] Related Publications
The significance of melanoma differentiation-associated gene-7/interleukin-24 (MDA-7/IL-24) expression in head and neck squamous cell carcinoma (HNSCC) remains unclear. This study was designed to investigate and evaluate the clinical significance of MDA-7/IL-24 expression in HNSCC by detecting expression by immunostaining in 131 HNSCC specimens. The function of MDA-7/IL-24 was investigated by real-time polymerase chain reaction (PCR) and Western blot in Ad5.mda-7-infected HNSCC cell lines. Our results showed that MDA-7/IL-24 was mainly expressed in the cytoplasm of HNSCC cells. MDA-7/IL-24 high patients presented with a favorable postoperative prognosis compared with MDA-7/IL-24 low patients, and high expression of MDA-7/IL-24 was significantly correlated with a lower incidence of second primary malignancies (SPMs) in the head and neck regions. In vitro assays showed that high expression of MDA-7/IL-24 could upregulate the expression of the epithelial terminal differentiation markers cytokeratin (KRT) 1, KRT4, KRT13, phosphorylated endoplasmic reticulum stress protein (p)-EIF2a, and the apoptosis-related protein cleaved caspase-3. It also downregulated the epithelial proliferative markers KRT5, KRT14, Integrin β4, and anti-apoptosis protein Bcl-2, which might be partially involved in the underlying mechanisms of Ad.mda-7-mediated HNSCC differentiation and apoptosis. Our results indicate that MDA-7/IL-24 can be a prognostic biomarker and an indicator of second primary malignancies (SPM) in HNSCC.

Banyard J, Chung I, Migliozzi M, et al.
Identification of genes regulating migration and invasion using a new model of metastatic prostate cancer.
BMC Cancer. 2014; 14:387 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Understanding the complex, multistep process of metastasis remains a major challenge in cancer research. Metastasis models can reveal insights in tumor development and progression and provide tools to test new intervention strategies.
METHODS: To develop a new cancer metastasis model, we used DU145 human prostate cancer cells and performed repeated rounds of orthotopic prostate injection and selection of subsequent lymph node metastases. Tumor growth, metastasis, cell migration and invasion were analyzed. Microarray analysis was used to identify cell migration- and cancer-related genes correlating with metastasis. Selected genes were silenced using siRNA, and their roles in cell migration and invasion were determined in transwell migration and Matrigel invasion assays.
RESULTS: Our in vivo cycling strategy created cell lines with dramatically increased tumorigenesis and increased ability to colonize lymph nodes (DU145LN1-LN4). Prostate tumor xenografts displayed increased vascularization, enlarged podoplanin-positive lymphatic vessels and invasive margins. Microarray analysis revealed gene expression profiles that correlated with metastatic potential. Using gene network analysis we selected 3 significantly upregulated cell movement and cancer related genes for further analysis: EPCAM (epithelial cell adhesion molecule), ITGB4 (integrin β4) and PLAU (urokinase-type plasminogen activator (uPA)). These genes all showed increased protein expression in the more metastatic DU145-LN4 cells compared to the parental DU145. SiRNA knockdown of EpCAM, integrin-β4 or uPA all significantly reduced cell migration in DU145-LN4 cells. In contrast, only uPA siRNA inhibited cell invasion into Matrigel. This role of uPA in cell invasion was confirmed using the uPA inhibitors, amiloride and UK122.
CONCLUSIONS: Our approach has identified genes required for the migration and invasion of metastatic tumor cells, and we propose that our new in vivo model system will be a powerful tool to interrogate the metastatic cascade in prostate cancer.

Dentelli P, Traversa M, Rosso A, et al.
miR-221/222 control luminal breast cancer tumor progression by regulating different targets.
Cell Cycle. 2014; 13(11):1811-26 [PubMed] Free Access to Full Article Related Publications
α6β4 integrin is an adhesion molecule for laminin receptors involved in tumor progression. We present a link between β4 integrin expression and miR-221/222 in the most prevalent human mammary tumor: luminal invasive carcinomas (Lum-ICs). Using human primary tumors that display different β4 integrin expression and grade, we show that miR-221/222 expression inversely correlates with tumor proliferating index, Ki67. Interestingly, most high-grade tumors express β4 integrin and low miR-221/222 levels. We ectopically transfected miR-221/222 into a human-derived mammary tumor cell line that recapitulates the luminal subtype to investigate whether miR-221/222 regulates β4 expression. We demonstrate that miR-221/222 overexpression results in β4 expression downregulation, breast cancer cell proliferation, and invasion inhibition. The role of miR-221/222 in driving β4 integrin expression is also confirmed via mutating the miR-221/222 seed sequence for β4 integrin 3'UTR. Furthermore, we show that these 2 miRNAs are also key breast cancer cell proliferation and invasion regulators, via the post-transcriptional regulation of signal transducer and activator of transcription 5A (STAT5A) and of a disintegrin and metalloprotease-17 (ADAM-17). We further confirm these data by silencing ADAM-17, using a dominant-negative or an activated STAT5A form. miR-221/222-driven β4 integrin, STAT5A, and ADAM-17 did not occur in MCF-10A cells, denoted "normal" breast epithelial cells, indicating that the mechanism is cancer cell-specific.   These results provide the first evidence of a post-transcriptional mechanism that regulates β4 integrin, STAT5A, and ADAM-17 expression, thus controlling breast cancer cell proliferation and invasion. Pre-miR-221/222 use in the aggressive luminal subtype may be a powerful therapeutic anti-cancer strategy.

Chen Q, Xu R, Zeng C, et al.
Down-regulation of Gli transcription factor leads to the inhibition of migration and invasion of ovarian cancer cells via integrin β4-mediated FAK signaling.
PLoS One. 2014; 9(2):e88386 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Recent evidence suggests that aberrant activation of Hedgehog (Hh) signaling by Gli transcription factors is characteristic of a variety of aggressive human carcinomas including ovarian cancer. Therefore, chemotherapeutic agents that inhibit activation of Gli transcription factors have emerged as promising novel therapeutic drugs for ovarian cancer.
RESULTS: In this study, we show that activation of Hh signaling promoted cellular migration and invasion, whereas blockade of Hh signaling with GANT61 suppressed cellular migration and invasion in ovarian cancer cells. After treatment with GANT61, cDNA microarray analyses revealed changes in many genes such as Integrin β4 subunit (ITGB4), focal adhesion kinase (FAK), etc. Furthermore, ITGB4 expression was up-regulated by Sonic Hedgehog (Shh) ligand and down-regulated by Hh signaling inhibitor. The Shh-mediated ovarian cell migration and invasion was blocked by neutralizing antibodies to ITGB4. In addition, phosphorylations of FAK were increased by Shh and decreased by Hh signaling inhibitor. Inhibition of Gli1 expression using siRNA mimicked the effects of GANT61 treatment, supporting the specificity of GANT61. Further investigations showed that activation of FAK was required for Shh-mediated cell migration and invasion. Finally, we found that down-regulation of Gli reduced the expression of ITGB4 and the phosphorylated FAK, resulting in the inhibition of tumor growth in vivo.
CONCLUSIONS: The Hh signaling pathway induces cell migration and invasion through ITGB4-mediated activation of FAK in ovarian cancer. Our findings suggest that the diminishment of crosstalk between phosphorylated FAK and ITGB4 due to the down-regulation of Gli family transcription factors might play a pivotal role for inhibiting ovarian cancer progression.

Bernardes N, Ribeiro AS, Abreu S, et al.
High-throughput molecular profiling of a P-cadherin overexpressing breast cancer model reveals new targets for the anti-cancer bacterial protein azurin.
Int J Biochem Cell Biol. 2014; 50:1-9 [PubMed] Related Publications
Azurin is a bacterial protein from Pseudomonas aeruginosa which exerts an inhibitory activity in cancer cells. In P-cadherin-overexpressing models, a bad prognosis marker in breast cancer increasing invasion and other malignant features, azurin decreases the invasion of cancer cells. We performed a microarray analysis to compare the expression profile of azurin treated cells with different P-cadherin expression levels. Azurin up-regulated apoptosis mediated by p53 protein, endocytosis and vesicle-mediated transport. In the contrary, in invasive MCF-7/AZ.Pcad cells, azurin decreased the expression of genes associated with cell surface receptors and signal transduction, as well as biological adhesion. Further, azurin decreased adhesion of cells to proteins from the extracellular matrix (ECM) and altered protein expression of integrins α6, β4 and β1 and interfered with the ability of these cells to form mammospheres. Altogether, our results further enlighten the anti-cancer effects mediated by azurin in P-cadherin overexpression breast cancer models.

Chen CH, Wang SH, Liu CH, et al.
β-1,4-Galactosyltransferase III suppresses β1 integrin-mediated invasive phenotypes and negatively correlates with metastasis in colorectal cancer.
Carcinogenesis. 2014; 35(6):1258-66 [PubMed] Related Publications
Metastasis often occurs in colorectal cancer (CRC) patients and is the main difficulty in cancer treatment. The upregulation of poly-N-acetyllactosamine-related glycosylation is found in CRC patients and is associated with progression and metastasis in cancer. β-1,4-Galactosyltransferase III (B4GALT3) is an enzyme responsible for poly-N-acetyllactosamine synthesis, and therefore, we investigated its expression in CRC patients. We found that B4GALT3 negatively correlated with poorly differentiated histology (P < 0.001), advanced stages (P = 0.0052), regional lymph node metastasis (P = 0.0018) and distant metastasis (P = 0.0463) in CRC patients. B4GALT3 overexpression in CRC cells suppressed cell migration, invasion and adhesion, whereas B4GALT3 knockdown enhanced malignant cell phenotypes. The β1 integrin-blocking antibody reversed the B4GALT3-mediated increase in cell invasion. B4GALT3 expression altered glycosylation on the N-glycan of β1 integrin probably through changes in poly-N-acetyllactosamine expression. Furthermore, more activated β1 integrin along with the activation of its downstream signaling transduction were found in B4GALT3 knockdown cells, whereas overexpression of B4GALT3 suppressed the expression of active β1 integrin and inhibited its downstream signaling. Our results suggest that B4GALT3 is negatively associated with CRC metastasis and suppresses cell invasiveness through inhibiting activation of β1 integrin.

Li L, Hu Y, Ylivinkka I, et al.
NETRIN-4 protects glioblastoma cells FROM temozolomide induced senescence.
PLoS One. 2013; 8(11):e80363 [PubMed] Free Access to Full Article Related Publications
Glioblastoma multiforme is the most common primary tumor of the central nervous system. The drug temozolomide (TMZ) prolongs lifespan in many glioblastoma patients. The sensitivity of glioblastoma cells to TMZ is interfered by many factors, such as the expression of O-6-methylguanine-DNA methyltransferase (MGMT) and activation of AKT signaling. We have recently identified the interaction between netrin-4 (NTN4) and integrin beta-4 (ITGB4), which promotes glioblastoma cell proliferation via activating AKT-mTOR signaling pathway. In the current work we have explored the effect of NTN4/ITGB4 interaction on TMZ induced glioblastoma cell senescence. We report here that the suppression of either ITGB4 or NTN4 in glioblastoma cell lines significantly enhances cellular senescence. The sensitivity of GBM cells to TMZ was primarily determined by the expression of MGMT. To omit the effect of MGMT, we concentrated on the cell lines devoid of expression of MGMT. NTN4 partially inhibited TMZ induced cell senescence and rescued AKT from dephosphorylation in U251MG cells, a cell line bearing decent levels of ITGB4. However, addition of exogenous NTN4 displayed no significant effect on TMZ induced senescence rescue or AKT activation in U87MG cells, which expressed ITGB4 at low levels. Furthermore, overexpression of ITGB4 combined with exogenous NTN4 significantly attenuated U87MG cell senescence induced by TMZ. These data suggest that NTN4 protects glioblastoma cells from TMZ induced senescence, probably via rescuing TMZ triggered ITGB4 dependent AKT dephosphorylation. This suggests that interfering the interaction between NTN4 and ITGB4 or concomitant use of the inhibitors of the AKT pathway may improve the therapeutic efficiency of TMZ.

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