The compound licofelone inhibited oral cancer growth by inhibiting the cyclooxygenase (COX) and 5-lipoxygenase pathways, according to a study presented at this week's American Association for Cancer Research International Conference in Anaheim, CA.
COX inhibitors have been shown to suppress oral and other cancers, but side effects, such as gastric bleeding, tend to disqualify them as preventive agents. Researchers at the ITT Research Institute in Chicago hypothesized that suppressing COX might instigate cancer-causing inflammation through lipoxygenase (LOX). Because licofelone inhibits both pathways, the researchers investigated whether it could provide superior cancer prevention while lowering toxicity, according to a Science Daily story.
The researchers used a rat model to induce oral cancer and tested different licofelone doses, including 37.5 mg/kg per day and 75 mg/kg per day, as well as 75 mg/kg per day after a six-week delay following the induction of cancer.
In a control group, 75% of the rats developed squamous cell carcinoma, the predominant oral cancer in humans, most often at the base of the tongue. They also developed a variety of precancerous lesions.
Some 43% of the rats assigned to high-dose licofelone and 55% assigned to the low-dose administration developed cancer. Those assigned to the compound after a six-week delay had a 34% incidence of oral cancer. The researchers noted that delayed administration can compromise the anticancer activity in some compounds. The fact that licofelone retained its anticancer action bodes well for its preventive potential, as patients may have already developed precancerous lesions before they seek treatment, according to the story.
Researchers also observed a decreased incidence of the most advanced cancers with licofelone: a 17% incidence with both doses, compared with 54% in controls.
Although cancer incidence was reduced in the treated rats, the incidence of precursor lesions increased, confirming licofelone's ability to suppress the development of oral cancer, according to the story.
