ETS variant 5 promotes colorectal cancer angiogenesis by targeting platelet‐derived growth factor BB

Abstract

ETS transcription factors play important roles in tumor cell invasion, differentiation and angiogenesis. In this study, we initially demonstrated that ETS translocation variant 5 (ETV5) is abnormally upregulated in colorectal cancer (CRC), is positively correlated with CRC tumor size, lymphatic metastasis and tumor node metastasis (TNM) stage and indicates shorter survival and disease‐free survival in CRC patients. In vitro and in vivo experiments revealed that the downregulation of ETV5 could significantly suppress CRC cell proliferation. Moreover, overexpression of ETV5 could stimulate CRC angiogenesis in vitro and in vivo, which is consistent with RNA‐seq results. Then, we identified platelet‐derived growth factor BB (PDGF‐BB) as a direct target of ETV5 that plays an important role in ETV5‐mediated CRC angiogenesis through an angiogenesis antibody microarray. Additionally, PDGF‐BB could activate VEGFA expression via the PDGFR‐β/Src/STAT3 pathway in CRC cells and appeared to be positively correlated with ETV5 in CRC tissues. Finally, we revealed that ETV5 could bind directly to the promoter region of PDGF‐BB and regulate its expression through ChIP and luciferase assays. Overall, our study suggested that the transcription factor ETV5 could stimulate CRC malignancy and promote CRC angiogenesis by directly targeting PDGF‐BB. These findings suggest that EVT5 may be a potential new diagnostic and prognostic marker in CRC and that targeting ETV5 might be a potential therapeutic option for inhibiting CRC angiogenesis.

Targeting tumor cell-derived CCL2 as a strategy to overcome bevacizumab resistance in ETV5+ colorectal cancer

“…Some previous studies also revealed that the ETS family triggered angiogenesis in multiple tumors [13,17,18]. Similarly, our previous study showed that ETV5 facilitated CRC angiogenesis via PDGF-BB/Src/STAT3/VEGFA signaling pathway [19]. Besides, more and more studies indicated that chemokine signaling played critical roles in tumor angiogenesis, such as CCL2/CCR2 signaling and CXCL11/CXCR7 signaling [20,21].…”

“…Lentiviral particles were transduced into CRC cells according to the manufacturer's instructions, followed by stable selection. Lentivirus transfection was performed as described previously [19]. Antibiotic puromycin was used to select stably transfected cells.…”

“…Cell viability and colony formation assays were performed as described previously [19]. Approximately 3000 cells were plated in 96-well plates and cultured in a 37 °C/5% CO2 incubator.…”

“…ChIP assays were performed following the chromatin immunoprecipitation kit (Millipore) protocol, as previously described [19]. Brie y, an anti-ETV5 antibody (Santa Cruz Biotechnology, SC-22807) was used for immunoprecipitation.…”

“…FFPE slides with CRC specimens and nude mice tumor tissue sections were stained as previously described [3,19]. Antibodies used for IHC included antibodies against ETV5 (ab102010, Abcam), VEGFA (ab46154, Abcam), CD31 (3528, Cell Signaling Technology), Ki67 (1:200, Santa Cruz), and CCL2 (ab9669).…”