NEW PROTEIN MAY BE THE ACHILLES’S HEEL OF TREATMENT-RESISTANT HEAD AND NECK CANCER

800px-Proportions_of_the_HeadResearchers at the University of Michigan, Ann Arbor believe they have solved the mystery behind why some head and neck cancer cells are refractory to the effects of radiation and chemotherapy and extremely adept at repairing and thriving under such aggressive insults. According to the findings of a new study from the group of Dr. Nisha J D’Silva that appeared in Nature Communications this week, a protein named TRIP-13 is responsible for enabling cancer cells to repair their damaged DNA using a process called error-prone non-homologous end joining. Using recombinant DNA technology, the group also showed that normal cells could be transformed into malignant cancer cells by overexpression of TRIP-13.

Head and neck cancer is one of the most common cancers in the world, and often afflicts users of tobacco and alcohol, as well as people infected with the Human Papillomavirus (HPV). The malignancy often starts in the squamous cells lining the moist surfaces of the head and neck, and can quickly spread through most of the oral cavity. Adding to its severity is the fact that the cancer is notoriously resistant to treatment and comes with a high recurrence rate.

Dr. D’Silva’s research findings offer a plausible explanation for such a high recurrence rate and overall intractability of head and neck cancer. Adding to the hope is the group’s  identification of an existing molecule potent in killing these TRIP-13-expressing cells, offering a direct and potentially speedy treatment option for the near future.

Antioxidants: to take or not to take?

A new study published in Science Translational Medicine shows that antioxidants, specifically vitamin E and acetylcysteine (NAC), can actually worsen lung cancer in mice, putting to question the popular belief that antioxidants fight cancer.

An antioxidant is any molecule that prevents oxidation of other molecules by reacting with free radicals produced naturally as a byproduct of oxygen metabolism. Free radicals can react with normal cells and cause damage to cells and even to their DNA. A damaged DNA can increase the likelihood of developing cancer. Luckily, the body has its own line of antioxidants that neutralize the damaging effects of free radicals on healthy cells. Based on this reasoning, several companies actually extract antioxidants from various sources and sell them for use as dietary supplements, supporting the notion that antioxidants promote good health.

DNA damage, however, is not always a bad thing. It can induce the expression of tumor suppressor genes such as p53, which work to prevent emergence of cancerous cells. Thus, the running debate among scientists and doctors alike has been whether or not antioxidants should be recommended to patients with cancer. On one hand, they reduce DNA damage, which can lead to cancerous cells, while on the other hand; they obstruct the beneficial tumor suppressor genes.

According to the data generated by Sayin et al., antioxidants are a bad idea, if cancer already exists. The authors report “antioxidant supplementation of the diet reduces DNA damage in mice, prevents p53 activation, and markedly increases tumor cell proliferation and tumor growth in mice.”

The authors speculate that “antioxidants are unsafe in patients with early stages of lung cancer and in people at risk of developing the disease…this may be relevant to patients with chronic obstructive pulmonary disease, who are often smokers with an increased risk of developing lung cancer and ingest high amounts of NAC to relieve mucus production.”

It seems that when it comes to good health, there is really no magic pill. Thus, like most dietary supplements, antioxidants should also be taken only at the recommendation of a doctor.