Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, Coppito 2, 67100, L'Aquila, Italy.
Medical Oncology Unit, St. Salvatore Hospital, 67100, L'Aquila, Italy.
J Cancer Res Clin Oncol. 2020 Jun;146(6):1427-1440. doi: 10.1007/s00432-020-03186-x. Epub 2020 Apr 6.
RAS mutational status in colorectal cancer (CRC) represents a predictive biomarker of response to anti-EGFR therapy, but to date it cannot be considered an appropriate biomarker of response to anti-VEGF therapy. To elucidate the function of K-Ras in promoting angiogenesis, the effect of conditioned media from KRAS mutated and wild type colon cancer cell lines on HUVECs tubule formation ability and the correspondent production of pro-angiogenic factors have been evaluated by a specific ELISA assay.
Ras-activated signaling pathways were compared by western blot analysis and RTq-PCR. In addition, VEGF, IL-8, bFGF and HIF-1α expression was determined in K-RAS silenced cells. Furthermore, we conducted an observational study in a cohort of RAS mutated metastatic CRC patients, treated with first-line bevacizumab-based regimens, evaluating VEGF-A and IL-8 plasma levels at baseline, and during treatment.
K-RAS promotes VEGF production by cancer cell lines. At the transcriptional level, this is reflected to a K-RAS dependent HIF-1α over-expression. Moreover, the HIF-1α, VEGF and FGF expression inhibition in KRAS knocked cells confirmed these results. Within the clinical part, no statistically significant correlation has been found between progression-free survival (PFS) and VEGF-A/IL-8 levels, but we cannot exclude that these biomarkers could be further investigated as predictive or prognostic biomarkers in this setting.
Our study confirmed the direct involvement of K-Ras in promoting angiogenesis into colon cancer cell lines.
结直肠癌（CRC）中的 RAS 突变状态是抗 EGFR 治疗反应的预测生物标志物，但迄今为止，它不能被认为是抗 VEGF 治疗反应的合适生物标志物。为了阐明 K-Ras 在促进血管生成中的作用，通过特定的 ELISA 测定评估了 KRAS 突变和野生型结肠癌细胞系的条件培养基对 HUVEC 小管形成能力和相应的促血管生成因子产生的影响。
通过 Western blot 分析和 RTq-PCR 比较 Ras 激活的信号通路。此外，在 K-RAS 沉默的细胞中确定了 VEGF、IL-8、bFGF 和 HIF-1α 的表达。此外，我们在一组接受一线贝伐珠单抗为基础的方案治疗的 RAS 突变转移性 CRC 患者中进行了一项观察性研究，在基线和治疗期间评估了 VEGF-A 和 IL-8 的血浆水平。
K-RAS 通过癌细胞系促进 VEGF 的产生。在转录水平上，这反映了 K-RAS 依赖性 HIF-1α 的过表达。此外，在 KRAS 敲除细胞中抑制 HIF-1α、VEGF 和 FGF 的表达证实了这些结果。在临床部分，未发现无进展生存期（PFS）和 VEGF-A/IL-8 水平之间存在统计学显著相关性，但我们不能排除这些生物标志物可以在这种情况下进一步作为预测或预后生物标志物进行研究。
我们的研究证实了 K-Ras 直接参与促进结肠癌细胞系的血管生成。
