Vitamin C has long been associated with a range of health benefits from strengthening the body's immune system to preventing wrinkles and cardiovascular diseases.
Now, findings of a new research suggest that the vitamin naturally found in bell peppers, oranges and broccoli may also help in fighting colorectal cancer.
In the new study published in the journal Science, Lewis Cantley of Weill Cornel Medicine in New York, and colleagues exposed colorectal cancer cells with mutations in KRAS and BRAF genes, which are linked to cell growth, to high plasma levels of vitamin C.
They found that the mutated cells take in the vitamin's oxidized form via an overexpressed receptor in the mutated cells. This results in the cancer cells to undergo oxidative stress, which turns off the enzyme the mutated cells need to reproduce.
The researchers conducted an experiment with mice and found that vitamin C destroyed the mutated cancer cells. Just like with cell culture results, the researchers found that high dose of vitamin C inhibited the growth of tumors in mice that were characterized by KRAS mutation.
Cantley and colleagues noted the potentials of vitamin C since regular therapies for cancer are not capable of targeting mutated cells. The oxidative stress induced by large dose of vitamin C inactivated the enzyme needed by the mutant cells but not the normal cells. Over half of colorectal cancers in humans are also marked by mutations in either KRAS or BRAF and tend to be resilient to approved targeted therapies.
"High-dose vitamin C impaired tumor growth in Apc/KrasG12D mutant mice," the researchers wrote in their study. "These results provide a mechanistic rationale for exploring the therapeutic use of vitamin C for CRCs with KRAS or BRAF mutations."
Scientists hope that vitamin C therapy could also be used in other KRAS-driven diseases such as pancreatic cancer although further research is still needed if the results seen in mice could also be duplicated in humans.
The use of vitamin C in treating cancer, however, is highly contentious since studies conducted on the vitamin's efficacy as cancer treatment had varied and contradictory results. Some studies suggested that high doses of vitamin C may reverse the growth of liver, prostate, and other kinds of cancer cells but some of these studies were eventually found to be flawed.
"The idea that vitamin C could be an effective therapy for human cancer holds great appeal, but its track record in this arena has been highly controversial, with clinical studies producing contradictory results," the American Association for the Advancement of Science said in a statement.