Gene Summary

Gene:FLT1; fms related tyrosine kinase 1
Aliases: FLT, FLT-1, VEGFR1, VEGFR-1
Summary:This gene encodes a member of the vascular endothelial growth factor receptor (VEGFR) family. VEGFR family members are receptor tyrosine kinases (RTKs) which contain an extracellular ligand-binding region with seven immunoglobulin (Ig)-like domains, a transmembrane segment, and a tyrosine kinase (TK) domain within the cytoplasmic domain. This protein binds to VEGFR-A, VEGFR-B and placental growth factor and plays an important role in angiogenesis and vasculogenesis. Expression of this receptor is found in vascular endothelial cells, placental trophoblast cells and peripheral blood monocytes. Multiple transcript variants encoding different isoforms have been found for this gene. Isoforms include a full-length transmembrane receptor isoform and shortened, soluble isoforms. The soluble isoforms are associated with the onset of pre-eclampsia.[provided by RefSeq, May 2009]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:vascular endothelial growth factor receptor 1
Source:NCBIAccessed: 11 March, 2017


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 (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.

Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

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: FLT1 (cancer-related)

Lin X, Khalid S, Qureshi MZ, et al.
VEGF mediated signaling in oral cancer.
Cell Mol Biol (Noisy-le-grand). 2016; 62(14):64-68 [PubMed] Related Publications
Increasingly it is being realized that oral cancer arises from genetic/epigenetic mutations, dysregulations of spatio-temporally controlled signal transduction cascades and loss of apoptosis. Epidemiological studies have provided a stronger association between tobacco use (chewed and smoked) and oral cancer. Nevertheless, alcohol has also gained attention as a significant risk factor, having a multiplicative synergistic cancer promoting effect with tobacco. Vascular Endothelial Growth Factor (VEGF) mediated signaling has gained limelight because of its instrumental role in endothelial cell proliferation, survival, invasion, migration, chemotaxis of bone marrow (BM)-derived progenitor cells, vasodilation and vascular permeability. In this review we provide most recent updates on involvement of VEGF/VEGFR signaling axis in oral cancer. We partition this multi-component review into different sections and summarize latest advancements related to therapies against VEGF/VEGFR signaling axis and how microRNAs tactfully modulate VEGF and VEGFR in oral cancers. Data obtained through preclinical and clinical studies has revealed that therapeutic benefits associated with VEGF-targeted therapy are complicated in different cancers and involve myriad of mechanisms. A better understanding of VEGF/VEGFR mediated signaling in oral cancers and testing of novel therapeutic agents in preclinical models will prove to be helpful in effective translation of safest drugs from benchtop to the bedside.

Dang YZ, Zhang Y, Li JP, et al.
High VEGFR1/2 expression levels are predictors of poor survival in patients with cervical cancer.
Medicine (Baltimore). 2017; 96(1):e5772 [PubMed] Free Access to Full Article Related Publications
The aim of the study to evaluate the prognostic significance of vascular endothelial growth factor receptor 1 and 2 (VEGFR1/2) expression levels and to correlate these levels with clinicopathological parameters in patients with cervical cancer.Forty-two patients with International Federation of Gynecology and Obstetrics Stage IIB-IVB cervical cancer were analyzed between January 2011 and December 2012. RNA expression levels of VEGFR1/2 were assessed by branched DNA-liquidchip technology and immunohistochemistry. Associations between RNA expression levels, important clinicopathological parameters, and patient survival were statistically evaluated.Higher VEGFR1/2 expression levels were predictive of poor overall survival (P = 0.009 and P = 0.024, respectively). Patients with higher VEGFR1 expression levels were associated with poorer progression-free survival than those with lower VEGFR1 expression levels (P = 0.043). In addition, patients with higher VEGFR1 expression levels were more likely to develop distant metastases than those with lower VEGFR1 expression levels (P = 0.049). Higher VEGFR2 expression levels were associated with larger tumor size (P = 0.037).VEGFR1/2 expression levels were prognostic factors for patients with cervical cancer. Higher VEGFR1/2 expression levels were also predictive of poor overall survival.

Chekhonin IV, Gurina OI, Cherepanov SA, et al.
Pulsed Dendritic Cells for the Therapy of Experimental Glioma.
Bull Exp Biol Med. 2016; 161(6):792-796 [PubMed] Related Publications
We obtained the morphologically, cytofluorometrically, and functionally mature dendritic cells from rats that were pulsed with antigens of the C6 glioma tissue extract. The concentrations of angiogenesis antigens (VEGF, VEGFR-1, and VEGFR-2) and periglioma zone proteins (GFAP, connexin 43, and BSAT1) in the pulsing extract were measured by ELISA. Our results drove us to a conclusion that despite mature phenotype of pulsed dendritic cell, the antigenic composition of glioma tissue extracts should be modified.

Majeed W, Iftikhar A, Khaliq T, et al.
Gastric Carcinoma: Recent Trends in Diagnostic Biomarkers and Molecular Targeted Therapies.
Asian Pac J Cancer Prev. 2016; 17(7):3053-60 [PubMed] Related Publications
Gastric cancer is generally associated with poor survival rates and accounts for a remarkable proportion of global cancer mortality. The prevalence of gastric carcinoma varies in different regions of world and across teh various ethnic groups. On the basis of pathological assessment, gastric cancer can be categorized as intestinal and diffuse carcinomas. The etiology is diverse, including chemical carcinogen exposure, and high salt intake Helicobacter pylori also plays a vital role in the pathogenesis of certain gastric carcinomas. The development of gastric cancer involves various alterations in mRNAs, genes (GOLPH3, MTA2) and proteins (Coronins). miRNAs, Hsamir135b, MiR21, miR106b, miR17, miR18a, MiR21, miR106b, miR17, miR18a and MiRNA375, miRNA1955p are the latest diagnostic biomarkers which can facilitate the early diagnosis of gastric carcinomas. Recent development in the treatment strategies for gastric carcinoma include the introduction of monoclonal antibodies, TKI inhibitors, inhibitors of PDGFR β, VEGFR1, VEGFR2, AntiEGFR and antiHER2 agents which can be applied along with conventional therapies.

Mehta S, Hughes NP, Li S, et al.
Radiogenomics Monitoring in Breast Cancer Identifies Metabolism and Immune Checkpoints as Early Actionable Mechanisms of Resistance to Anti-angiogenic Treatment.
EBioMedicine. 2016; 10:109-16 [PubMed] Free Access to Full Article Related Publications
Anti-VEGF antibody bevacizumab has prolonged progression-free survival in several cancer types, however acquired resistance is common. Adaption has been observed pre-clinically, but no human study has shown timing and genes involved, enabling formulation of new clinical paradigms. In a window-of-opportunity study in 35 ductal breast cancer patients for 2weeks prior to neoadjuvant chemotherapy, we monitored bevacizumab response by Dynamic Contrast-Enhanced Magnetic Resonance [DCE-MRI], transcriptomic and pathology. Initial treatment response showed significant overall decrease in DCE-MRI median K(trans), angiogenic factors such ESM1 and FLT1, and proliferation. However, it also revealed great heterogeneity, spanning from downregulation of blood vessel density and central necrosis to continued growth with new vasculature. Crucially, significantly upregulated pathways leading to resistance included glycolysis and pH adaptation, PI3K-Akt and immune checkpoint signaling, for which inhibitors exist, making a strong case to investigate such combinations. These findings support that anti-angiogenesis trials should incorporate initial enrichment of patients with high K(trans), and a range of targeted therapeutic options to meet potential early resistance pathways. Multi-arm adaptive trials are ongoing using molecular markers for targeted agents, but our results suggest this needs to be further modified by much earlier adaptation when using drugs affecting the tumor microenvironment.

Schlieve CR, Mojica SG, Holoyda KA, et al.
Vascular Endothelial Growth Factor (VEGF) Bioavailability Regulates Angiogenesis and Intestinal Stem and Progenitor Cell Proliferation during Postnatal Small Intestinal Development.
PLoS One. 2016; 11(3):e0151396 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Vascular endothelial growth factor (VEGF) is a highly conserved, master regulatory molecule required for endothelial cell proliferation, organization, migration and branching morphogenesis. Podocoryne carnea and drosophila, which lack endothelial cells and a vascular system, express VEGF homologs, indicating potential roles beyond angiogenesis and vasculogenesis. The role of VEGF in the development and homeostasis of the postnatal small intestine is unknown. We hypothesized regulating VEGF bioavailability in the postnatal small intestine would exhibit effects beyond the vasculature and influence epithelial cell stem/progenitor populations.
METHODS: VEGF mutant mice were created that overexpressed VEGF in the brush border of epithelium via the villin promotor following doxycycline treatment. To decrease VEGF bioavailability, sFlt-1 mutant mice were generated that overexpressed the soluble VEGF receptor sFlt-1 upon doxycycline administration in the intestinal epithelium. Mice were analyzed after 21 days of doxycycline administration.
RESULTS: Increased VEGF expression was confirmed by RT-qPCR and ELISA in the intestine of the VEGF mutants compared to littermates. The VEGF mutant duodenum demonstrated increased angiogenesis and vascular leak as compared to littermate controls. The VEGF mutant duodenum revealed taller villi and increased Ki-67-positive cells in the transit-amplifying zone with reduced Lgr5 expression. The duodenum of sFlt-1 mutants revealed shorter villi and longer crypts with reduced proliferation in the transit-amplifying zone, reduced expression of Dll1, Bmp4 and VE-cadherin, and increased expression of Sox9 and EphB2.
CONCLUSIONS: Manipulating VEGF bioavailability leads to profound effects on not only the intestinal vasculature, but epithelial stem and progenitor cells in the intestinal crypt. Elucidation of the crosstalk between VEGF signaling in the vasculature, mesenchyme and epithelial stem/progenitor cell populations may direct future cell therapies for intestinal dysfunction or disease.

Dornbusch J, Walter M, Gottschalk A, et al.
Evaluation of polymorphisms in angiogenesis-related genes as predictive and prognostic markers for sunitinib-treated metastatic renal cell carcinoma patients.
J Cancer Res Clin Oncol. 2016; 142(6):1171-82 [PubMed] Related Publications
PURPOSE: Single nucleotide polymorphisms (SNPs) in angiogenesis-associated genes might play an important role in activity of the tyrosine kinase inhibitor sunitinib and could affect survival of cancer patients treated with this drug. The aim of this retrospective study was to elucidate the role of 10 known SNPs in VEGFA, VEGFR1, VEGFR2 and VEGFR3 as potential prognostic and predictive markers in an independent cohort of patients with metastatic renal cell carcinoma (mRCC).
METHODS: DNA from 121 mRCC patients treated with sunitinib was used to analyze SNPs by TaqMan genotyping assays. Disease control rate was evaluated according to RECIST. Adverse effects of sunitinib were registered from medical records. The results of Cox and logistic regression were verified by correction for multiple testing.
RESULTS: Kaplan-Meier analysis revealed a reduced progression-free survival in patients with the wild-type (WT) allele of the VEGFA SNP rs699947 compared to variant alleles. Patients with the AA/AC-alleles of the VEGFR1 SNP rs9582036 had an improved median overall survival compared to those with the CC-WT allele what could be confirmed by multivariable Cox proportional hazard regression analyses. No statistically significant associations between the analyzed SNPs and higher risk for adverse effects were observed.
CONCLUSIONS: The results of this study suggest that most of the selected SNPs in angiogenesis-related genes are not associated with survival of mRCC patients after sunitinib therapy or with adverse effects. Only the VEGFR1 SNP rs9582036 showed a statistically significant association with overall survival. The potential of SNPs as prognostic and predictive markers for sunitinib-treated mRCC patients should be finally assessed by prospective studies.

Takahashi Y, Saga Y, Koyanagi T, et al.
Vasohibin-1 expression inhibits advancement of ovarian cancer producing various angiogenic factors.
Cancer Sci. 2016; 107(5):629-37 [PubMed] Free Access to Full Article Related Publications
Vasohibin-1 (VASH1) is a negative feedback regulator of angiogenesis, the first to be discovered, and was identified in vascular endothelial growth factor (VEGF)-stimulated vascular endothelial cells. Vasohibin-1 inhibits abnormal vascularization induced by various angiogenic factors including fibroblast growth factor and platelet-derived growth factor (PDGF), in addition to VEGF. By focusing on this characteristic of VASH1, we investigated the antitumor effects of VASH1 expression on ovarian cancer cells that produce different angiogenic factors. By using a high VEGF-producing ovarian cancer cell line, SHIN-3, and a high PDGF-producing ovarian cancer cell line, KOC-2S, the cells were transfected with either a VEGF antagonist, soluble VEGF receptor-1 (sVEGFR-1, or sFlt-1), or VASH1 genes to establish their respective cellular expression. The characteristics of these transfectants were compared with controls. We previously reported that the expression of sFlt-1 inhibited tumor vascularization and growth of high VEGF-producing ovarian cancer cells, reduced peritoneal dissemination and ascites development, and prolonged the survival time of the host. However, in the current study, the expression of sFlt-1 had no such effect on the high PDGF-producing ovarian cancer cells used here, whereas VASH1 expression inhibited tumor vascularization and growth, not only in high VEGF-producing cells, but also in high PDGF-producing cells, reduced their peritoneal dissemination and ascites, and prolonged the survival time of the host. These results suggest that VASH1 is an effective treatment for ovarian cancer cells that produce different angiogenic factors.

Okamoto S, Nitta M, Maruyama T, et al.
Bevacizumab changes vascular structure and modulates the expression of angiogenic factors in recurrent malignant gliomas.
Brain Tumor Pathol. 2016; 33(2):129-36 [PubMed] Related Publications
Bevacizumab (BV), a monoclonal antibody against vascular endothelial growth factor (VEGF), is currently used in the treatment of malignant glioma. To understand mechanisms of resistance to BV, we investigated morphological changes in tumor vessels and expression of angiogenic factors, such as VEGF, Flt-1, basic fibroblast growth factor (bFGF), and platelet-derived growth factor-BB (PDGF-BB), in four autopsied tumors after BV treatment. Three patients had glioblastomas; the fourth had a secondary glioblastoma that developed from a diffuse astrocytoma. BV was administered because of recurrence following the use of the Stupp regimen in these four patients. We compared the initial surgical specimen with that obtained after death following BV treatment. Immunohistochemical staining of the autopsied tumors showed that Flt-1 expression increased while VEGF expression was significantly reduced. Additionally, other angiogenic factors, particularly bFGF, were enhanced. Interestingly, the proliferation of endothelial cells was reduced, but remarkable proliferation of pericytes was observed. These results suggest that following BV treatment, glioblastomas can grow tumor vessels by expressing various angiogenic factors. These mechanisms might be important for rapid regrowth and blood brain barrier repair after BV treatment. Inhibition of multiple angiogenic factors will be required to control tumor vessels in glioblastoma.

Skirnisdottir I, Seidal T, Åkerud H
The relationship of the angiogenesis regulators VEGF-A, VEGF-R1 and VEGF-R2 to p53 status and prognostic factors in epithelial ovarian carcinoma in FIGO-stages I-II.
Int J Oncol. 2016; 48(3):998-1006 [PubMed] Free Access to Full Article Related Publications
The aim of this study was to evaluate prognostic effect of the angiogenesis regulators VEGF-R1, VEGF-R2 and VEGF-A for recurrent disease and disease-free survival (DFS), and their relation to the apoptosis regulator p53, in 131 patients with FIGO-stages I-II with epithelial ovarian cancer. For the detection of positivity of the markers the techniques of tissue microarrays and immunohistochemistry (IHC) were used. In tumors the frequency of positive staining for VEGF-R1 was 19%, for VEGF-R2 and VEGF-A, it was 77 and 70%, respectively. Positivity for p53 was detected in 25% of tumors. The total number of recurrences in the complete series was 34 out of 131 (26%) and 5-year disease-free survival (DFS) was 68%. Positive staining for VEGF-A (P=0.030), VEGF-R2 (P=0.011) and p53 (P=0.015) was found more frequently in type II tumors than in type I tumors. Patients with VEGF-R1 negative tumors had worse (P=0.021) DFS compared to patients with VEGF-R1 positive tumors. In two multivariate Cox analyzes with DFS as endpoint, FIGO-stage (HR=3.8), VEGF-R2 status (HR=0.4) and p53 status (HR=2.3), all were significant and independent prognostic factors. When the variables VEGF-R2 and p53 were replaced with the new variable VEGF-R2+p53-/other three combinations in one group, it was found that patients from that subgroup had 86% reduced risk of dying in disease (HR=0.24). Findings above, confirmed relationship between VEGF-R2 and VEGF-A and p53, respectively, with regard to recurrent disease and survival. Some findings from the present study are different from results from previous studies on the regulation of angiogenesis. Despite many trials with anti-angiogenic agents in the front line of ovarian cancer have shown to be positive for progression-free survival, no one has demonstrated an impact on overall survival. Therefore, one of the greatest challenges in ovarian cancer research, is to discover predictive and prognostic biomarkers.

Vaeteewoottacharn K, Kariya R, Dana P, et al.
Inhibition of carbonic anhydrase potentiates bevacizumab treatment in cholangiocarcinoma.
Tumour Biol. 2016; 37(7):9023-35 [PubMed] Related Publications
Cholangiocarcinoma (CCA) is a unique liver cancer subtype with an increasing incidence globally. The lack of specific symptoms and definite diagnostic markers results in a delayed diagnosis and disease progression. Systemic chemotherapy is commonly selected for advanced CCA even though its advantages remain unknown. Targeted therapy, especially anti-vascular endothelial growth factor (VEGF) therapy, is promising for CCA; however, improvements in the therapeutic regimen are necessary to overcome subsequent resistance. We demonstrated VEGF expression was higher in CCA cell lines than in other liver cancer cells. Secreted VEGFs played roles in the induction of peri- and intra-tumoral vascularization. VEGF neutralization by bevacizumab effectively reduced tumor growth, mainly through the suppression of angiogenesis; however, increases in the expression of hypoxia-inducible factor 1α (HIF1α) and HIF1α-responsive genes (such as VEGF, VEGFR1, VEGFR2, carbonic anhydrase (CA) IX and CAXII) indicated the potential for subsequent therapeutic resistance. Supplementation with a carbonic anhydrase inhibitor, acetazolamide, enhanced the anti-CCA effects of bevacizumab. Anti-angiogenesis and anti-proliferation were observed with the combination treatment. These results suggested a novel treatment strategy to overcome anti-angiogenesis resistance and the importance of "induced essentiality" in the treatment of CCA.

Polanska H, Heger Z, Gumulec J, et al.
Effect of HPV on tumor expression levels of the most commonly used markers in HNSCC.
Tumour Biol. 2016; 37(6):7193-201 [PubMed] Related Publications
Approximately 90 % of head and neck cancers are squamous cell carcinomas (HNSCC), and the overall 5-year survival rate is not higher than 50 %. There is much evidence that human papillomavirus (HPV) infection may influence the expression of commonly studied HNSCC markers. Our study was focused on the possible HPV-specificity of molecular markers that could be key players in important steps of cancerogenesis (MKI67, EGF, EGFR, BCL-2, BAX, FOS, JUN, TP53, MT1A, MT2A, VEGFA, FLT1, MMP2, MMP9, and POU5F). qRT-PCR analysis of these selected genes was performed on 74 biopsy samples of tumors from patients with histologically verified HNSCC (22 HPV-, 52 HPV+). Kaplan-Meier analysis was done to determine the relevance of these selected markers for HNSCC prognosis. In conclusion, our study confirms the impact of HPV infection on commonly studied HNSCC markers MT2A, MMP9, FLT1, VEGFA, and POU5F that were more highly expressed in HPV-negative HNSCC patients and also shows the relevance of studied markers in HPV-positive and HPV-negative HNSCC patients.

Kopp S, Warnke E, Wehland M, et al.
Mechanisms of three-dimensional growth of thyroid cells during long-term simulated microgravity.
Sci Rep. 2015; 5:16691 [PubMed] Free Access to Full Article Related Publications
Three-dimensional multicellular spheroids (MCS) of human cells are important in cancer research. We investigated possible mechanisms of MCS formation of thyroid cells. Both, normal Nthy-ori 3-1 thyroid cells and the poorly differentiated follicular thyroid cancer cells FTC-133 formed MCS within 7 and 14 days of culturing on a Random Positioning Machine (RPM), while a part of the cells continued to grow adherently in each culture. The FTC-133 cancer cells formed larger and numerous MCS than the normal cells. In order to explain the different behaviour, we analyzed the gene expression of IL6, IL7, IL8, IL17, OPN, NGAL, VEGFA and enzymes associated cytoskeletal or membrane proteins (ACTB, TUBB, PFN1, CPNE1, TGM2, CD44, FLT1, FLK1, PKB, PKC, ERK1/2, Casp9, Col1A1) as well as the amount of secreted proteins (IL-6, IL-7, IL-8, IL-17, OPN, NGAL, VEGFA). Several of these components changed during RPM-exposure in each cell line. Striking differences between normal and malignant cells were observed in regards to the expression of genes of NGAL, VEGFA, OPN, IL6 and IL17 and to the secretion of VEGFA, IL-17, and IL-6. These results suggest several gravi-sensitive growth or angiogenesis factors being involved in 3D formation of thyroid cells cultured under simulated microgravity.

Li T, Zhu Y, Han L, et al.
VEGFR-1 activation-induced MMP-9-dependent invasion in hepatocellular carcinoma.
Future Oncol. 2015; 11(23):3143-57 [PubMed] Free Access to Full Article Related Publications
AIM: VEGFR-1 can promote invasion through epithelial-mesenchymal transition induction in hepatocellular carcinoma (HCC). This study aims to elucidate VEGFR-1 impact on proteolytic enzymes profile involved with invasion.
MATERIALS & METHODS: The effect on cell invasion was evaluated by invasive and migration assays with and without VEGFR-1 activation. The mechanism was investigated by real-time PCR, western blot and gelatin zymography using inhibitors for MMP-9. In total, 95 HCC patients were enrolled for its clinical value evaluation.
RESULTS: VEGFR-1 activation induced invasion in HCC cells with an increase in the expression and activity of MMP-9 and Snail. MMP-9 blockage effectively inhibited VEGFR-1-induced invasion. High coexpression of both in HCC predicted a worse clinical outcome.
CONCLUSION: Data show a novel VEGFR-1 activation-to-MMP-9 mechanism promoting HCC invasion.

Manzat-Saplacan RM, Balacescu L, Gherman C, et al.
Is there a correlation between peripheral blood expression of angiogenic transcriptional factors/receptors and colorectal cancer?
J BUON. 2015 Sep-Oct; 20(5):1193-200 [PubMed] Related Publications
PURPOSE: The aim of this study was to evaluate whether there is a correlation between peripheral blood expression of angiogenic transcriptional factors/receptors and colorectal cancer (CRC).
METHODS: Eighty six blood samples collected from patients with CRC (N=42), adenomas and/or hyperplastic polyps(AP, N=30) and individuals without colon pathology (control group/CTR, N=14) were used for this study. Twelve transcription factors and receptors were assessed by qRT-PCR in a case-control study. The molecules with a minimum of 30% differences in gene expression for CRC and AP compared to CTR were then analyzed separately for each sample. Gene expression was evaluated relatively to the CTR after normalization to the large ribosomal protein PO (RPLPO) housekeeping gene, and the differential expression between studied groups was assessed by ANOVA.
RESULTS: Seven out of 12 genes presented differences in expression between 10-29% in CRC and/or AP compared to CTR. Considering the selection criteria, we further individually evaluated the levels of expression of 5 genes that had a minimum of 30% expression in the case-control study. Our data showed a significant up-regulation of platelet derived growth factor (PDGF) C in the blood of the patients with CRC compared to CTR (p=0.007). Likewise, clusterin (CLU) was significantly up-regulated both in CRC and AP groups compared to healthy subjects (p=0.01). For VEGFR1, PDGFRA and TGFB1 we didn't find significantly differential expression between any of the studied groups, even if increased levels were observed in both CRC and AP vs CTR.
CONCLUSIONS: The results of our study indicated that increased blood level of PDGFC mRNA was associated with the presence of CRC (p=0.007). Additionally, high levels of circulating CLU mRNA were observed in both malignant and benign colorectal pathologies.

Fernández-Guizán A, López-Soto A, Acebes-Huerta A, et al.
Pleiotropic Anti-Angiogenic and Anti-Oncogenic Activities of the Novel Mithralog Demycarosyl-3D-ß-D-Digitoxosyl-Mithramycin SK (EC-8042).
PLoS One. 2015; 10(11):e0140786 [PubMed] Free Access to Full Article Related Publications
Demycarosyl-3D-ß-D-digitoxosyl-mithramycin SK (DIG-MSK) is a recently isolated analogue of mithramycin A (MTA) that showed differences with MTA in the DNA binding strength and selectivity. These differences correlated with a better therapeutic index and less toxicity in animal studies. Herein, we show that DIG-MSK displays a potent anti-tumor activity against different types of cancer cell lines, ovarian tumor cells being particularly sensitive to this drug. Of relevance, DIG-MSK exerts low toxicity on fibroblasts and peripheral blood mononuclear cells, this toxicity being significantly lower than that of MTA. In correlation with its antitumor activity, DIG-MSK strongly inhibited Sp1-mediated transcription and endogenous Sp1 mRNA expression, which correlated with the inhibition of the expression of key Sp1-regulated genes involved in tumorigenesis, including VEGFA, BCL2L1 (Bcl-XL), hTERT, BRCA2, MYC and SRC in several ovarian cells. Significantly, DIG-MSK was a stronger inhibitor of VEGFA expression than MTA. Accordingly, DIG-MSK also exhibited potent anti-angiogenic activity on microvascular endothelial cells. Likewise, it significantly inhibited the gene expression of VEGFR1, VEGFR2, FGFR, PDGFB and PDGFRA and, additionally, it induced the expression of the anti-angiogenic factors angiostatin and tunstatin. These effects correlated with a pro-apoptotic effect on proliferating microvascular endothelial cells and the inhibition of the formation of endothelial capillary structures. Overall, the pleiotropic activity of DIG-MSK in inhibiting key oncogenic and angiogenic pathways, together with its low toxicity profile, highlight the therapeutic potential of this new drug.

Pinheiro C, Garcia EA, Morais-Santos F, et al.
Reprogramming energy metabolism and inducing angiogenesis: co-expression of monocarboxylate transporters with VEGF family members in cervical adenocarcinomas.
BMC Cancer. 2015; 15:835 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Deregulation of cellular energetic metabolism was recently pointed out as a hallmark of cancer cells. This deregulation involves a metabolic reprogramming that leads to a high production of lactate. Lactate efflux, besides contributing for the glycolytic flux, also acts in the extracellular matrix, contributing for cancer malignancy, by, among other effects, induction of angiogenesis. However, studies on the interplay between cancer metabolism and angiogenesis are scarce. Therefore, the aim of the present study was to evaluate the metabolic and vascular molecular profiles of cervical adenocarcinomas, their co-expression, and their relation to the clinical and pathological behavior.
METHODS: The immunohistochemical expression of metabolism-related proteins (MCT1, MCT4, CD147, GLUT1 and CAIX) as well as VEGF family members (VEGF-A, VEGF-C, VEGF-D, VEGFR-1, VEGFR-2 and VEGFR-3) was assessed in a series of 232 cervical adenocarcinomas. The co-expression among proteins was assessed and the expression profiles were associated with patients' clinicopathological parameters.
RESULTS: Among the metabolism-related proteins, MCT4 and CAIX were the most frequently expressed in cervical adenocarcinomas while CD147 was the less frequently expressed protein. Overall, VEGF family members showed a strong and extended expression with VEGF-C and VEGFR-2 as the most frequently expressed and VEGFR-1 as the less expressed member. Co-expression of MCT isoforms with VEGF family members was demonstrated. Finally, MCT4 was associated with parametrial invasion and HPV18 infection, CD147 and GLUT1 with distant metastasis, CAIX with tumor size and HPV18 infection, and VEGFR-1 with local and lymphnode metastasis.
CONCLUSIONS: The results herein presented provide additional evidence for a crosstalk between deregulating cellular energetics and inducing angiogenesis. Also, the metabolic remodeling and angiogenic switch are relevant to cancer progression and aggressiveness in adenocarcinomas.

Barr MP, O'Byrne KJ, Al-Sarraf N, Gray SG
VEGF-mediated cell survival in non-small-cell lung cancer: implications for epigenetic targeting of VEGF receptors as a therapeutic approach.
Epigenomics. 2015; 7(6):897-910 [PubMed] Related Publications
AIMS: To evaluate the potential therapeutic utility of histone deacetylase inhibitors (HDACi) in targeting VEGF receptors in non-small-cell lung cancer.
MATERIALS & METHODS: Non-small-cell lung cancer cells were screened for the VEGF receptors at the mRNA and protein levels, while cellular responses to various HDACi were examined.
RESULTS: Significant effects on the regulation of the VEGF receptors were observed in response to HDACi. These were associated with decreased secretion of VEGF, decreased cellular proliferation and increased apoptosis which could not be rescued by addition of exogenous recombinant VEGF. Direct remodeling of the VEGFR1 and VEGFR2 promoters was observed. In contrast, HDACi treatments resulted in significant downregulation of the Neuropilin receptors.
CONCLUSION: Epigenetic targeting of the Neuropilin receptors may offer an effective treatment for lung cancer patients in the clinical setting.

Wang F, He Z, Dai W, et al.
The role of the vascular endothelial growth factor/vascular endothelial growth factor receptors axis mediated angiogenesis in curcumin-loaded nanostructured lipid carriers induced human HepG2 cells apoptosis.
J Cancer Res Ther. 2015 Jul-Sep; 11(3):597-605 [PubMed] Related Publications
BACKGROUND: Curcumin (diferuloylmethane), the active constituent of turmeric extract has potent anti-cancer properties have been demonstrated in hepatocellular carcinoma (HCC). However, its underlying molecular mechanism of therapeutic effects remains unclear. Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) have crucial roles in tumor angiogenesis.
PURPOSE: The goal of this study was to investigate the role of the VEGF/VEGFRs mediated angiogenesis during the proliferation and apoptosis of human HepG2 hepatoma cell line and the effect of curcumin-loaded nanostructured lipid carriers (Cur-NLC).
MATERIALS AND METHODS: The proliferation of HepG2 cells was determined by methyl thiazolyl tetrazolium after exposure to Cur-NLC and native curcumin. Apoptosis was quantified by flow cytometry with annexin V-fluorescein isothiocyanate and propidium iodide staining. Cellular internalization of Cur-NLC was observed by fluorescent microscope. The level of VEGF was detected by enzyme-linked immunosorbent assay kits. The expression of VEGFRs was quantified by Western blotting.
RESULTS: Cur-NLC was more effective in inhibiting the proliferation and enhancing the apoptosis of HepG2 cells than native curcumin. Fluorescent microscope analysis showed that HepG2 cells internalized Cur-NLC more effectively than native curcumin. Furthermore, Cur-NLC down-regulated the level of VEGF and the expression of VEGFR-2, but had a slight effect on VEGFR-1.
CONCLUSION: These results clearly demonstrated that Cur-NLC was more effective in anti-cancer activity than the free form of curcumin. These studies demonstrate for the 1 st time that Cur-NLC exerts an antitumor effect on HepG2 cells by modulating VEGF/VEGFRs signaling pathway.

Bedal KB, Grässel S, Spanier G, et al.
The NC11 domain of human collagen XVI induces vasculogenic mimicry in oral squamous cell carcinoma cells.
Carcinogenesis. 2015; 36(11):1429-39 [PubMed] Related Publications
Collagen XVI, a fibril-associated collagen with interrupted triple helix (FACIT) collagen, is involved in oral squamous cell carcinoma (OSCC) and glioblastoma progression. The NC11 domain of collagen XVI has been described previously with a strong implication in physiological processes. We detected the non-collagenous (NC) 11-domain in supernatants of OSCC cells after recombinant expression of full-length collagen XVI and in sera from OSCC patients and healthy individuals. Stable expression of NC11-green fluorescent protein (GFP) fusion protein in OSCC cells initiated proliferation control and block of anchorage-independent growth. Moreover, the NC11 domain triggered the generation of tubular-like net structures on laminin-rich matrix in contrast to mock-GFP control cells and cells expressing full-length collagen XVI. Taqman® quantitative PCR and diaminobenzidine staining in 2D- and 3D cell culture revealed a significantly increased gene and protein expression of VEGFR1, VEGFR2 and uPAR in recombinant NC11-GFP-expressing cells. Specific VEGF receptor inhibition with Axitinib or fetal calf serum heat inactivation prevented formation of tubular-like net structures. Accordantly, NC11-GFP coated culture slides led to an increase of focal adhesion contact formation and the upregulation of VEGFR1 and uPAR in three different non-transfected OSCC cell lines. In summary, we suggest that the NC11 domain of collagen XVI is a potential biomarker for OSCC and triggers vasculogenic mimicry via upregulation of endothelial receptors VEGFR1, VEGFR2 and uPAR in 2D- and 3D OSCC cell culture conditions.

Paiva TF, de Jesus VH, Marques RA, et al.
Angiogenesis-related protein expression in bevacizumab-treated metastatic colorectal cancer: NOTCH1 detrimental to overall survival.
BMC Cancer. 2015; 15:643 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The development of targeted therapies has undoubtedly broadened therapeutic options for patients with colorectal cancer (CRC). The use of bevacizumab to reduce angiogenesis has been associated with improved clinical outcomes. However, an urgent need for prognostic/predictive biomarkers for anti-angiogenic therapies still exists.
METHODS: Clinical data of 105 CRC patients treated with bevacizumab in conjunction with chemotherapy were analyzed. The expression of vascular endothelial growth factor (VEGF) receptors, NOTCH1 receptor and its ligand DLL4 were determined by immunohistochemistry. Tumor samples were arranged on a tissue microarray. The association between protein expression and clinicopathological characteristics and outcomes was determined.
RESULTS: Bevacizumab was administered as a first-line of treatment in 70.5 % of our cases. The median progression-free survival (PFS) was 10.2 months. The median overall survival (OS) of the total cohort was 24.4 months. Bevacizumab, as the first-line of treatment, and the presence of liver metastasis were independently associated with objective response rate. Membrane VEGFR1 and VEGFR3 expressions were associated with the presence of lung metastasis; interestingly, VEGFR3 was associated with less liver metastasis. NOTCH1 expression was associated with lymph node metastasis. There was a trend toward association between improved PFS and lower NOTCH1 expression (p = 0.06). Improved OS was significantly associated with lower NOTCH1 expression (p = 0.01). In a multivariate analysis, ECOG (Eastern Cooperative Oncology Group) performance status, liver metastasis, histological grade, and NOTCH1 expression were independently associated with OS.
CONCLUSION: Our findings illustrated the expression profile of angiogenesis-related proteins and their association with clinicopathological characteristics and outcomes. NOTCH1 expression is a detrimental prognostic factor in metastatic CRC patients treated with chemotherapy plus bevacizumab.

Kennedy AL, Vallurupalli M, Chen L, et al.
Functional, chemical genomic, and super-enhancer screening identify sensitivity to cyclin D1/CDK4 pathway inhibition in Ewing sarcoma.
Oncotarget. 2015; 6(30):30178-93 [PubMed] Free Access to Full Article Related Publications
Ewing sarcoma is an aggressive bone and soft tissue tumor in children and adolescents, with treatment remaining a clinical challenge. This disease is mediated by somatic chromosomal translocations of the EWS gene and a gene encoding an ETS transcription factor, most commonly, FLI1. While direct targeting of aberrant transcription factors remains a pharmacological challenge, identification of dependencies incurred by EWS/FLI1 expression would offer a new therapeutic avenue. We used a combination of super-enhancer profiling, near-whole genome shRNA-based and small-molecule screening to identify cyclin D1 and CDK4 as Ewing sarcoma-selective dependencies. We revealed that super-enhancers mark Ewing sarcoma specific expression signatures and EWS/FLI1 target genes in human Ewing sarcoma cell lines. Particularly, a super-enhancer regulates cyclin D1 and promotes its expression in Ewing sarcoma. We demonstrated that Ewing sarcoma cells require CDK4 and cyclin D1 for survival and anchorage-independent growth. Additionally, pharmacologic inhibition of CDK4 with selective CDK4/6 inhibitors led to cytostasis and cell death of Ewing sarcoma cell lines in vitro and growth delay in an in vivo Ewing sarcoma xenograft model. These results demonstrated a dependency in Ewing sarcoma on CDK4 and cyclin D1 and support exploration of CDK4/6 inhibitors as a therapeutic approach for patients with this disease.

Djokovic D, Trindade A, Gigante J, et al.
Incomplete Dll4/Notch signaling inhibition promotes functional angiogenesis supporting the growth of skin papillomas.
BMC Cancer. 2015; 15:608 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: In invasive malignancies, Dll4/Notch signaling inhibition enhances non-functional vessel proliferation and limits tumor growth by reducing its blood perfusion.
METHODS: To assess the effects of targeted Dll4 allelic deletion in the incipient stages of tumor pathogenesis, we chemically induced skin papillomas in wild-type and Dll4 (+/-) littermates, and compared tumor growth, their histological features, vascularization and the expression of angiogenesis-related molecules.
RESULTS: We observed that Dll4 down-regulation promotes productive angiogenesis, although with less mature vessels, in chemically-induced pre-cancerous skin papillomas stimulating their growth. The increase in endothelial activation was associated with an increase in the VEGFR2 to VEGFR1 ratio, which neutralized the tumor-suppressive effect of VEGFR-targeting sorafenib. Thus, in early papillomas, lower levels of Dll4 increase vascularization through raised VEGFR2 levels, enhancing sensitivity to endogenous levels of VEGF, promoting functional angiogenesis and tumor growth.
CONCLUSION: Tumor promoting effect of low-dosage inhibition needs to be considered when implementing Dll4 targeting therapies.

Almamun M, Levinson BT, van Swaay AC, et al.
Integrated methylome and transcriptome analysis reveals novel regulatory elements in pediatric acute lymphoblastic leukemia.
Epigenetics. 2015; 10(9):882-90 [PubMed] Free Access to Full Article Related Publications
Acute lymphoblastic leukemia (ALL) is the most common cancer diagnosed in children under the age of 15. In addition to genetic aberrations, epigenetic modifications such as DNA methylation are altered in cancer and impact gene expression. To identify epigenetic alterations in ALL, genome-wide methylation profiles were generated using the methylated CpG island recovery assay followed by next-generation sequencing. More than 25,000 differentially methylated regions (DMR) were observed in ALL patients with ∼ 90% present within intronic or intergenic regions. To determine the regulatory potential of the DMR, whole-transcriptome analysis was performed and integrated with methylation data. Aberrant promoter methylation was associated with the altered expression of genes involved in transcriptional regulation, apoptosis, and proliferation. Novel enhancer-like sequences were identified within intronic and intergenic DMR. Aberrant methylation in these regions was associated with the altered expression of neighboring genes involved in cell cycle processes, lymphocyte activation and apoptosis. These genes include potential epi-driver genes, such as SYNE1, PTPRS, PAWR, HDAC9, RGCC, MCOLN2, LYN, TRAF3, FLT1, and MELK, which may provide a selective advantage to leukemic cells. In addition, the differential expression of epigenetic modifier genes, pseudogenes, and non-coding RNAs was also observed accentuating the role of erroneous epigenetic gene regulation in ALL.

Qian BZ, Zhang H, Li J, et al.
FLT1 signaling in metastasis-associated macrophages activates an inflammatory signature that promotes breast cancer metastasis.
J Exp Med. 2015; 212(9):1433-48 [PubMed] Free Access to Full Article Related Publications
Although the link between inflammation and cancer initiation is well established, its role in metastatic diseases, the primary cause of cancer deaths, has been poorly explored. Our previous studies identified a population of metastasis-associated macrophages (MAMs) recruited to the lung that promote tumor cell seeding and growth. Here we show that FMS-like tyrosine kinase 1 (Flt1, also known as VEGFR1) labels a subset of macrophages in human breast cancers that are significantly enriched in metastatic sites. In mouse models of breast cancer pulmonary metastasis, MAMs uniquely express FLT1. Using several genetic models, we show that macrophage FLT1 signaling is critical for metastasis. FLT1 inhibition does not affect MAM recruitment to metastatic lesions but regulates a set of inflammatory response genes, including colony-stimulating factor 1 (CSF1), a central regulator of macrophage biology. Using a gain-of-function approach, we show that CSF1-mediated autocrine signaling in MAMs is downstream of FLT1 and can restore the tumor-promoting activity of FLT1-inhibited MAMs. Thus, CSF1 is epistatic to FLT1, establishing a link between FLT1 and inflammatory responses within breast tumor metastases. Importantly, FLT1 inhibition reduces tumor metastatic efficiency even after initial seeding, suggesting that these pathways represent therapeutic targets in metastatic disease.

Siamakpour-Reihani S, Owzar K, Jiang C, et al.
Prognostic significance of differential expression of angiogenic genes in women with high-grade serous ovarian carcinoma.
Gynecol Oncol. 2015; 139(1):23-9 [PubMed] Free Access to Full Article Related Publications
OBJECTIVES: To identify angiogenic biomarkers associated with tumor angiogenesis and clinical outcome in high-grade serous ovarian cancer (HGSC).
METHODS: 51 HGSC samples were analyzed using Affymetrix HG-U133A microarray. Microvessel density (MVD) counts were determined using CD31 and CD105. Associations between mRNA expression levels and overall survival were assessed using rank score statistic. Effect size was estimated as a hazard ratio (HR) under a proportional hazard model. The Storey q-value method was used to account for multiple testing within the false-discovery rate (FDR) framework. Publicly available databases including TCGA and GSE were used for external confirmation.
RESULTS: Thirty-one angiogenic-related genes were significantly associated with survival (q≤0.05). Of these 31 genes, 4 were also associated with outcome in the TCGA data: AKT1 (q=0.02; TCGA p=0.01, HR=0.8), CD44 (q=0.003; TCGA p=0.05, HR=0.9), EPHB2 (q=0.01; TCGA p=0.05, HR=1.2), and ERBB2 (q=0.02; TCGA p=0.05, HR=1.2). While 5 were associated with outcome in the GSE database: FLT1 (q=0.03; GSE26712 p=0.01, HR=3.1); PF4 (q=0.02; GSE26712 p=0.01, HR=3.0); NRP1 (q=0.02; GSE26712 p<0.04, HR>1.4); COL4A3 (q=0.04; GSE26712 p=0.03, HR=1.3); and ANGPTL3 (q=0.02; GSE14764 p=0.02, HR=1.5). High AKT1 and CD44 were associated with longer survival. In contrast, high expression of EPHB2, ERBB2, FLT1; PF4, NRP1, COL4A3, and ANGPTL3 were associated with shorter survival. CD105-MVD and CD31-MVD were not significantly associated with angiogenic gene expression.
CONCLUSIONS: Thirty-one angiogenic-related genes were associated with survival in advanced HGSC and nine of these genes were confirmed in independent publicly available databases.

Pedrosa AR, Trindade A, Carvalho C, et al.
Endothelial Jagged1 promotes solid tumor growth through both pro-angiogenic and angiocrine functions.
Oncotarget. 2015; 6(27):24404-23 [PubMed] Free Access to Full Article Related Publications
Angiogenesis is an essential process required for tumor growth and progression. The Notch signaling pathway has been identified as a key regulator of the neo-angiogenic process. Jagged-1 (Jag1) is a Notch ligand required for embryonic and retinal vascular development, which direct contribution to the regulation of tumor angiogenesis remains to be fully characterized. The current study addresses the role of endothelial Jagged1-mediated Notch signaling in the context of tumoral angiogenesis in two different mouse tumor models: subcutaneous Lewis Lung Carcinoma (LLC) tumor transplants and the autochthonous Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP). The role of endothelial Jagged1 in tumor growth and neo-angiogenesis was investigated with endothelial-specific Jag1 gain- and loss-of-function mouse mutants (eJag1OE and eJag1cKO). By modulating levels of endothelial Jag1, we observed that this ligand regulates tumor vessel density, branching, and perivascular maturation, thus affecting tumor vascular perfusion. The pro-angiogenic function is exerted by its ability to positively regulate levels of Vegfr-2 while negatively regulating Vegfr-1. Additionally, endothelial Jagged1 appears to exert an angiocrine function possibly by activating Notch3/Hey1 in tumor cells, promoting proliferation, survival and epithelial-to-mesenchymal transition (EMT), potentiating tumor development. These findings provide valuable mechanistic insights into the role of endothelial Jagged1 in promoting solid tumor development and support the notion that it may constitute a promising target for cancer therapy.

Henary H, George GC, Wheler J, et al.
A phase 1 study of intermittently administered pazopanib in combination with continuous daily dosing of lapatinib in patients with solid tumors.
Cancer Chemother Pharmacol. 2015; 76(3):597-603 [PubMed] Related Publications
PURPOSE: Preclinically, pazopanib/lapatinib combination acted synergistically to suppress the activity of multiple tyrosine kinases, including VEGFR-1, 2, 3, PDGFR and c-kit (pazopanib), HER1/EGFR and HER2 (lapatinib), and several other tyrosine kinases including c-Met through, plausibly, network inhibition effects. Clinically, continuous dosing of pazopanib/lapatinib combination was associated with a higher response rate than with lapatinib monotherapy, with poor tolerance. We explored multiple intermittent dose levels of pazopanib combined with continuous daily dosing of lapatinib in patients with solid tumors.
METHODS: The present study used a phase 1, modified 3 + 3, dose-escalation design to evaluate the safety and tolerability of the combination of orally received pazopanib once every other day with continuous daily dosing of lapatinib for 28 days. In the expansion phase, tumor response was evaluated in patients with specific genetic alterations (HER2 amplification, HER2 mutation, c-Met amplification, c-Met mutation, and EGFR mutation).
RESULTS: Twenty-four patients were treated. The most common drug-related adverse events were fatigue 7/24 (29%), skin rash 5/21 (21%), and diarrhea 3/24 (17%), with 4/24 (16%) patients experiencing grade ≥3 drug-related adverse events. Escalation to the FDA-approved dose (800 mg daily for pazopanib and 1500 mg every day for lapatinib) was not feasible due to toxicities. Pazopanib 200 mg every other day + lapatinib 500 mg daily was considered the maximum tolerated dose (MTD). No tumor response was observed, including in patients with the specific molecular genetic alterations tested.
CONCLUSION: Every other day dosing of pazopanib combined with daily lapatinib was tolerated at the established MTD, but no complete or partial tumor responses were observed at these dose levels.

Gahr S, Mayr C, Kiesslich T, et al.
The pan-deacetylase inhibitor panobinostat affects angiogenesis in hepatocellular carcinoma models via modulation of CTGF expression.
Int J Oncol. 2015; 47(3):963-70 [PubMed] Related Publications
Post-translational modifications of chromatin components are significantly involved in the regulation of tumor suppressor gene and oncogene expression. Connective tissue growth factor (CTGF) is an epigenetically regulated growth factor with functions in angiogenesis and cell-matrix interactions and plays a pivotal role in hepatocellular carcinoma (HCC). The pharmacologic inhibition of histone and protein deacetylases represents a new approach to interfere with pathways of apoptosis and angiogenesis. We investigated the effect of the pan-deacetylase inhibitor panobinostat (LBH589) on human HCC cell lines HepG2 (p53wt) and Hep3B (p53null) and in a subcutaneous xenograft model and explored the influence on angiogenesis. Specimens were characterized by quantitative real-time PCR. Protein was separated for western blotting against CTGF, VEGF, VEGF receptor-1 (VEGFR-1/FLT-1), VEGF receptor-2 (VEGFR-2/KDR), MAPK and phospho-MAPK. In vivo, HepG2 cells were xenografted to NMRI mice and treated with daily i.p. injections of 10 mg/kg panobinostat. After 1, 7 and 28 days, real-time PCR was performed. Immunohistochemistry and western blotting were examined after 28 days. An increased significant expression of CTGF was only seen after 24 h treatment with 0.1 µM panobinostat in HepG2 cells and Hep3B cells, whereas after 72 h treatment CTGF expression clearly decreased. In the xenografts, treatment with panobinostat showed a minimal CTGF expression after 1 day and 4 weeks, respectively. In vitro as well as in vivo, VEGF was not affected by panobinostat treatment at any time. In conclusion, panobinostat influences extracellular signaling cascades via CTGF-dependent pathways.

Tabernero J, Lenz HJ, Siena S, et al.
Analysis of circulating DNA and protein biomarkers to predict the clinical activity of regorafenib and assess prognosis in patients with metastatic colorectal cancer: a retrospective, exploratory analysis of the CORRECT trial.
Lancet Oncol. 2015; 16(8):937-48 [PubMed] Related Publications
BACKGROUND: Tumour mutational status is an important determinant of the response of metastatic colorectal cancer to targeted treatments. However, the genotype of the tissue obtained at the time of diagnosis might not accurately represent tumour genotype after multiple lines of treatment. This retrospective exploratory analysis investigated the clinical activity of regorafenib in biomarker subgroups of the CORRECT study population defined by tumour mutational status or plasma protein levels.
METHODS: We used BEAMing technology to identify KRAS, PIK3CA, and BRAF mutations in DNA obtained from the plasma of 503 patients with metastatic colorectal cancer who enrolled in the CORRECT trial. We quantified total human genomic DNA isolated from plasma samples for 503 patients using a modified version of human long interspersed nuclear element-1 (LINE-1) quantitive real-time PCR. We also measured the concentration of 15 proteins of interest-angiopoietin 2, interleukin 6, interleukin 8, placental growth factor, soluble TIE-1, soluble VEGFR1, VEGF-A, VEGF-C, VEGF-D, VEGF-A isoform 121, bone morphogenetic protein 7, macrophage colony-stimulating factor, stromal cell-derived factor-1, tissue inhibitor of metalloproteinase 2, and von Willebrand factor-in plasma samples from 611 patients. We did correlative analyses of overall survival and progression-free survival in patient subgroups based on mutational status, circulating DNA concentration, and protein concentrations. The CORRECT trial was registered with ClinicalTrials.gov, number NCT01103323.
FINDINGS: Tumour-associated mutations were readily detected with BEAMing of plasma DNA, with KRAS mutations identified in 349 (69%) of 503 patients, PIK3CA mutations in 84 (17%) of 503 patients, and BRAF mutations in 17 (3%) of 502 patients. We did not do correlative analysis based on BRAF genotype because of the low mutational frequency detected for this gene. Some of the most prevalent individual hot-spot mutations we identified included: KRAS (KRAS G12D, 116 [28%] of 413 mutations; G12V, 72 [17%]; and G13D, 67 [16%]) and PIK3CA (PIK3CA E542K, 27 [30%] of 89 mutations; E545K, 37 [42%]; and H1047R, 12 [14%]). 41 (48%) of 86 patients who had received anti-EGFR therapy and whose archival tumour tissue DNA was KRAS wild-type in BEAMing analysis were identified as having KRAS mutations in BEAMing analysis of fresh plasma DNA. Correlative analyses suggest a clinical benefit favouring regorafenib across patient subgroups defined by KRAS and PIK3CA mutational status (progression-free survival with regorafenib vs placebo: hazard ratio [HR] 0·52, 95% CI 0·35-0·76 for KRAS wild-type; HR 0·51, 95% CI 0·40-0·65 for KRAS mutant [KRAS wild type vs mutant, pinteraction=0·74]; HR 0·50, 95% CI 0·40-0·63 for PIK3CA wild-type; HR 0·54, 95% CI 0·32-0·89 for PIK3CA mutant [PIK3CA wild-type vs mutant, pinteraction=0·85]) or circulating DNA concentration (progression-free survival with regorafenib vs placebo: HR 0·53, 95% CI 0·40-0·71, for low circulating DNA concentrations; HR 0·52, 95% CI 0·40-0·70, for high circulating DNA concentrations; low vs high circulating DNA, pinteraction=0·601). With the exception of von Willebrand factor, assessed with the median cutoff method, plasma protein concentrations were also not associated with regorafenib activity in terms of progression-free survival. In univariable analyses, the only plasma protein that was associated with overall survival was TIE-1, high concentrations of which were associated with longer overall survival compared with low TIE-1 concentrations. This association was not significant in multivariable analyses.
INTERPRETATION: BEAMing of circulating DNA could be a viable approach for non-invasive analysis of tumour genotype in real time and for the identification of potentially clinically relevant mutations that are not detected in archival tissue. Additionally, the results show that regorafenib seems to be consistently associated with a clinical benefit in a range of patient subgroups based on mutational status and protein biomarker concentrations.
FUNDING: Bayer HealthCare Pharmaceuticals.

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