New aspirin compound has potential for cancer treatment
NEW YORK, NY - Recent studies have reported that aspirin has anticancer properties. Now, researchers at the City University of New York Medical School have developed a new “designer” form of aspirin that appears to be more effective than aspirin alone against cancer. The new formulation, known as NOSH-aspirin, was reported to be extremely effective in controlling the growth of the following cancers: adenomatous cancers (colon, pancreatic, lung, and prostate), epithelial cancer (breast), and lymphocytic cancer (leukemia).
NOSH-aspirin, is named because it releases nitric oxide (NO) and hydrogen sulfide (H2S). The research was published January 28 in the journal. ACS Medicinal Chemistry Letters.
The researchers note that NO and H2S are signaling substances, which are produced in the body; they dilate blood vessels, reduce inflammation, and have a variety of other effects. Previously, the researchers developed “designer” aspirin compounds that released either NO or H2S; these substances also did not appear to be a gastric (stomach) irritant. The new NOSH-aspirin compound might even be more effective than the two previous compounds and also safe for the stomach. The negative side of aspirin therapy is an increased risk of bleeding. Aspirin causes one additional bleeding ulcer for every 1,000 people using it for a year. It also increases the risk of bleeding in the brain, especially in seniors.
The researchers noted that some of the NOSH-aspirins tested were more than 100,000 times more effective against the growth of the aforementioned cancers than aspirin alone. In addition, they noted that the compound did not damage normal cells. According to the researchers, the lack of harm to the gastric mucosa was based on the observation that NO has some of the same properties as prostaglandins within the gastric mucosa. Therefore, coupling an NO-releasing agent to aspirin prevented stomach irritation. They noted that other studies of NO coupled to an anti-inflammatory agent noted that the compound was safer for the stomach than the anti-inflammatory agent by itself.
Several other studies with aspirin alone have reported its anticancer properties. A study published in the February 2012 issue of Cancer Prevention Research reported that daily aspirin treatment was associated with a significant reduction in colorectal cancer mortality. The researchers reviewed follow-up data of nearly 14,000 patients from four randomized, cardiovascular disease prevention trials; they found that showed that daily aspirin treatment for about five years was associated with a 34% reduction in 20-year colorectal cancer mortality. A separate meta-analysis of nearly 3,000 patients with a history of colorectal adenoma (a cancer precursor) or colorectal cancer in four randomized adenoma prevention trials found that aspirin reduced the occurrence of advanced adenomas by 28% and any adenoma by 17%. The researchers noted that aspirin had also been shown to be beneficial in a clinical trial of patients with Lynch syndrome, a hereditary type of colorectal cancer; individuals treated with aspirin for at least two years, experienced a 50% or more reduction in the risk of cancer commencing five years after the study and after aspirin had been discontinued. In addition, the study authors noted that a few observational studies have shown an increase in survival among patients with colorectal cancer who use aspirin.
They noted that taken together, these findings strengthen the case for consideration of long-term aspirin use in colorectal cancer prevention. They added, however, that despite these convincing data, a lack of consensus remains about the balance of risks and benefits associated with long-term aspirin use, particularly in low-risk populations. They also noted that the optimal dose to use for cancer prevention and the precise mechanism underlying aspirin's anticancer effect require further investigation.
According to a study published in the January 2102 issue of the same journal, Cancer Prevention Research, aspirin should be evaluated for its potential to prevent cervical cancer in women infected with HIV. The study found that the virus that causes AIDS also increases production of a prostaglandin known as PGE2 in cervical tissue. PGE2 is associated with inflammation and the development of tumors. The authors noted that aspirin is a potent blocker of a chemical known as COX-2, which allows prostaglandins to be formed. Because of this property, the authors suggested that a large study should be conducted to determine if low-dose aspirin could prevent cervical cancer in high-risk women. Cervical cancer is caused by the human papillomavirus (HPV), and some researchers believe women co-infected with HIV are up to five times more likely to have HPV lesions on their cervix progress to cancer. The authors noted that, currently, cervical cancer is not responsible many deaths for women who reside in affluent nations; however, it is a major cause of death in poor ones where Pap smears are too expensive and HPV vaccines are not yet available.
Another study, published online in the journal Lancet on October 28, reported that aspirin may reduce colorectal cancer risk by 60%. European researchers studied 861 individuals with Lynch syndrome who were randomly assigned to take aspirin or a placebo for up to four years. Approximately 50-70% of individuals with Lynch syndrome develop colorectal cancer. The disease occurs earlier and progresses more rapidly; thus, making them a group in whom preventive measures can be more easily studied than the general population. The researchers found that those who took daily aspirin for two years were 60% less likely to develop cancer of the colon or rectum than those not taking the medication. At an average follow-up of 55.7 months, 48 participants had developed 53 primary colorectal cancers (18 of 427 randomly assigned to aspirin; 30 of 434 to aspirin placebo).
Reference: ACS Medicinal Chemistry Letters