Addition of bevacizumab to weekly paclitaxel significantly improves progression-free survival in heavily pretreated recurrent epithelial ovarian cancer

VEGF directly suppresses activation of T cells from ascites secondary to ovarian cancer via VEGF receptor type 2

Background:

Vascular endothelial growth factor action in tumour angiogenesis is well characterised; nevertheless, it functions as a key element in the promotion of the immune system’s evasion by tumours. We sought to investigate the possible direct effect of VEGF on T-cell activation and through which type of VEGF receptor it exerts this effect on cells isolated from ovarian cancer patients’ ascites.

Methods:

T cells isolated from the ascites of ovarian cancer patients were cultured with anti-CD3 and IL-2, with or without VEGF for 14 days and the number of viable T cells was counted. Cytotoxic activity of cultured T cells and expression of VEGF receptor-2 (VEGFR-2), was assayed.

Results:

The addition of VEGF in cultures significantly reduced the number and proliferation rate of T cells in a dose-dependent manner and CD3⁺ T cells expressed VEGFR-2 on their surface upon activation. Experiments with specific anti-VEGFR-2 antibodies revealed that the direct suppressive effect of VEGF on T-cell proliferation is mediated by VEGFR-2. We also showed that VEGF significantly reduced the cytotoxic activity of T cells.

Conclusion:

Our study showed that ascites-derived T cells secrete VEGF and express VEGFR-2 upon activation. Vascular endothelial growth factor directly suppresses T-cell activation via VEGFR-2.

Monoclonal antibodies in gynecological cancer: a critical point of view

During the last decades, several improvements in treating gynecological malignancies have been achieved. In particular, target therapies, mostly monoclonal antibodies, have emerged as an attractive option for the treatment of these malignancies. In fact, various molecular-targeted agents have been developed for a variety of malignancies with the objective to interfere with a precise tumor associated receptor, essential for cancer cell survival or proliferation, blocking its function, of the cancer cells. Alternatively, monoclonal antibodies have been developed to block immune suppression or enhance functions of immune effector cells. So far, several monoclonal antibodies have been tested for clinical efficacy for the treatment of gynecological cancers. Antibodies against Vascular Endothelial Growth Factor (VEGF) and Epidermal Growth Factor Receptor (EGFR) have been used in different neoplasms such as ovarian and cervical cancer. Catumazumab, a bivalent antibody against CD3 and EpCAM, is effective in the treatment of neoplastic ascites. Other antibodies are peculiar for specific cancer-associated antigen such as Oregovomab against CA125 or Farletuzumab against the folate receptor. Here we describe the preclinical and clinical experience gained up to now with monoclonal antibodies in tumors of the female genital tract and trace future therapeutic and research venues.