Therapeutic Use of Vitamin C in Cancer: Physiological Considerations

Abstract

Since the early studies of William J. McCormick in the 1950s, vitamin C has been proposed as a candidate for the treatment of cancer. A number of reports have shown that pharmacological concentrations of vitamin C selectively kill cancer cells in vitro and decrease the growth rates of a number of human tumor xenografts in immunodeficient mice. However, up to the date there is still doubt regarding this possible therapeutic role of vitamin C in cancer, mainly because high dose administration in cancer patients has not showed a clear antitumor activity. These apparent controversial findings highlight the fact that we lack information on the interactions that occurs between cancer cells and vitamin C, and if these transformed cells can uptake, metabolize and compartmentalize vitamin C like normal human cells do. The role of SVCTs and GLUTs transporters, which uptake the reduced form and the oxidized form of vitamin C, respectively, has been recently highlighted in the context of cancer showing that the relationship between vitamin C and cancer might be more complex than previously thought. In this review, we analyze the state of art of the effect of vitamin C on cancer cells in vitro and in vivo, and relate it to the capacity of cancer cells in acquiring, metabolize and compartmentalize this nutrient, with its implications on the potential therapeutic role of vitamin C in cancer.

Antitumoral Properties of the Nutritional Supplement Ocoxin Oral Solution: A Comprehensive Review

“…Moreover, some reports have also demonstrated that vitamin C can inhibit growth of a number of human tumor xenografts in immunodeficient mice. In addition, some reports have also supported a chemopreventive action of vitamin C [33,34]. One of the relevant actions of vitamin C is its effect on cancer stem cells.…”

“…Moreover, vitamin C is an important contributor to immune defense of the body and has been found to be deficient in patients with advanced stages of cancer [33]. With independence of its mechanism of action, a large number of reports have shown that pharmacological concentrations of vitamin C can selectively kill cancer cells in vitro [34]. Moreover, some reports have also demonstrated that vitamin C can inhibit growth of a number of human tumor xenografts in immunodeficient mice.…”

Pancreatic Cancer (PDAC): Introduction of Evidence-Based Complementary Measures into Integrative Clinical Management

“…The essential characteristics of vitamin C (or ascorbic acid) and its potential usefulness against cancer, including PDAC, have recently been critically reviewed [ 195 ]. Humans cannot synthesize vitamin C, so it has to be consumed or taken as a supplement.…”

“…Vitamin C has two main modes of action that could ultimately lead to anti-cancer effects. First, it is primarily an antioxidant that may reduce the risk of developing cancer by preventing oxidative damage to normal cells [ 195 ]. Second, in the specific presence of catalytic metals, such as iron and copper, vitamin C may become a pro-oxidant and behave as an anti-cancer agent, e.g., via production of H 2 O 2 [ 196 , 197 ].…”

“…Importantly, two critical issues in ascorbic acid supplementation must be considered [ 195 ]. First, whilst plasma concentrations can reach a maximum of 100 μM when taken orally, it is i.v.…”