Anti-VEGF Mediated Immunomodulatory Role of Phytochemicals: Scientific Exposition for Plausible HCC Treatment

Abstract

Hepatocellular carcinoma (HCC) is one of the most common solid tumours and the second leading cause of cancer-related mortality worldwide. Advanced-recurrent HCC often requires a systemic drug therapy where multi tyrosine kinase inhibitor, Sorafenib represents the first-line therapy option. But it exhibited very limited survival benefit and tumour response due to the early emergence of drug resistance and drug-related adverse effect. Immunotherapy approaches now being widely studied as an effective alternative treatment for HCC. Several immune checkpoint inhibitors (ICI), such as Nivolumab and Pembrolizumab, are approved as monotherapy in sorafenib-resistant HCC patients. But, the existence of a plethora of immunosuppressive signals in the tumour microenvironment often leads to unsuccessful immunotherapies. In this context, combinatorial immunotherapies are getting much acceptance as a way to improve therapeutic outcomes by blocking immunosuppressive signals in the tumour microenvironment (TME). The combination of Vascular Endothelial Growth Factor (VEGF) inhibitors with ICI resulted in significant synergistic effects in various preclinical and clinical studies. However, the adverse effects associated with current synthetic VEGF inhibitors limit its clinical utility. In this review, we have summarized the potential of phytochemicals, especially the category of flavonoids, alkaloids, glycosides, terpenoids, and coumarin, as the available-affordable-safe-effective repositories of VEGF inhibitors. Their possibilities as an alternative for synthetic VEGF inhibitors by synergistic combination with ICI are reviewed, thereby enhancing patient compliance and survival rates. This review highlights the demand for a detailed investigation of the plausible role of plant-based anti-angiogenic-immunotherapy combination against HCC.

Keywords: Hepatocellular carcinoma; cytotoxic T cells; immunotherapy; neutrophils; phytoconstituents; regulatory T cells; vascular endothelial growth factors.