Panoply™ Human VEGFA Over-expressing Stable Cell Line

The clinical efficacy of immune checkpoint inhibitors (ICIs) is limited by a high rate of primary resistance, and VEGFA may contribute to the development of this resistance. Here, researchers evaluated the tumor microenvironment (TME) in human tumors and mouse tumor models characterized by high VEGFA expression, and investigated whether anti-angiogenic therapy could overcome primary resistance to ICIs in highly angiogenic mouse tumor models, as well as the underlying mechanisms. The results showed that high levels of VEGFA mRNA in human tumors were associated with poor prognosis and a TME characterized by hypoxia, active angiogenesis, and immunosuppression; furthermore, VEGFA upregulation enhanced the malignant phenotype of tumor cells both in vivo and in vitro. Models with high VEGFA expression exhibited a TME marked by hypoxia, hyper-angiogenesis, and immunosuppression, alongside primary resistance to ICIs. In tumor-bearing mice lacking high VEGFA expression, combination therapy failed to yield a synergistic anti-tumor effect compared to monotherapy; however, in tumors with high VEGFA expression, apatinib alleviated hyper-angiogenesis and hypoxia within the TME, transforming the immunosuppressive TME into an immune-activated one. Thus, anti-angiogenic therapy can enhance the efficacy of ICIs in tumors with high VEGFA expression. Identifying the presence of hyper-angiogenic features in tumor tissue can help guide the choice between anti-angiogenic therapy combined with ICIs and ICI monotherapy in cancer treatment.

Given that patients with tumors exhibiting high VEGFA expression often have a poor prognosis, researchers generated VEGFA-overexpressing CT26 and 4T1 cell lines (CT26-VEGFA and 4T1-VEGFA); simultaneously, CT26-NC and 4T1-NC cell lines were constructed using empty vectors to serve as controls. High VEGFA expression was verified via real-time quantitative PCR and Western blotting (Figure 1a, b). Subsequently, the effects of VEGFA overexpression were investigated in vitro. Cell growth curves demonstrated that VEGFA overexpression significantly promoted cell proliferation (Figure 1c). Furthermore, compared with cells carrying empty vectors, CT26-VEGFA and 4T1-VEGFA cells exhibited significantly higher colony formation efficiency (Figure 1d). Cell cycle distribution analysis revealed a marked increase in the proportion of cells in the S phase among the VEGFA-overexpressing cells (Figure 1e). Finally, VEGFA overexpression significantly enhanced the migration and invasion capabilities of CT26 and 4T1 cells (Figures 1f-g).

Figure 1. Efects of VEGFA overexpression on murine tumor cells in vitro. (Wang Q, et al., 2020)