Vitamin C as an Anticancer Agent: Regulation of Signaling Pathways

Treatment options for effective treatment of cancer with minimum off-target effects and maximum clinical outcomes have remained overarching goals in the clinical oncology. Vitamin C has remained in the shadows of controversy since the past few decades; burgeoning evidence has started to shed light on wide-ranging anticancer effects exerted by Vitamin C to induce apoptosis in drug-resistant cancer cells, inhibit uncontrolled proliferation of the cancer cells and metastatic spread. Landmark achievements in molecular oncology have ushered in a new era, and researchers have focused on the identification of oncogenic pathways regulated by Vitamin C in different cancers. However, there are visible knowledge gaps in our understanding related to the ability of Vitamin C to modulate a myriad of transduction cascades. There are scattered pieces of scientific evidence about promising potential of Vitamin C to regulate JAK-STAT, TGF/SMAD, TRAIL and microRNAs in different cancers. However, published data is insufficient and needs to be investigated comprehensively to enable basic and clinical researchers to reap full benefits and promote result-oriented transition of Vitamin C into various phases of clinical trials. In this review, we will emphasize on available evidence related to the regulation of oncogenic cell signaling pathways by Vitamin C in different cancers. We will also highlight the conceptual gaps, which need detailed and cutting-edge research.