Celecoxib, manufactured by Pfizer as Celebrex, is a part of the class of nonsteroidal anti-inflammatory drugs (NSAIDs). Specifically celecoxib targets the enzyme known as cyclooxygenase-2, or COX-2, which is linked to inflammatory responses. Thus, the drug is a potent prescription for patients with inflammatory joint pains, like osteoarthritis and rheumatoid arthritis.
Interestingly, COX-2 is also involved in the production of prostaglandins, which are hormone-like compounds that promote tumor growth. In multiple cancer types, COX-2 expression is found at much higher levels than compared to normal tissues. The team at the Scripps Research Institute (TSRI) stumbled upon this revelation almost by happenstance.
We were actually interested in determining what a particular signaling pathway does in cancer," said Joseph Kissil, TSRI Associate Professor, and senior study author. "In the process, we found that it activates genes that promote survival of tumor cells and that they do so by turning on enzymes involved in inflammation, including COX2, which anti-inflammatory drugs like Celebrex inhibit."
To test the anti-cancer effects of celecoxib, the research team used a tumor type known as neurofibromatosis type II (NF2). Patients who inherit rare mutations in the NF2 gene develop tumors in the auditory nerve. Animals with NF2 tumors were given daily doses of the celecoxib drug, and the research team imaged the tumor closely to assess whether the drug affected the tumor growth.
In their results, the team found that celecoxib-treated animals showed much slower tumor growth rate than the non-treated animals. "Our study shows that COX2 inhibitors do have an effect on the tumor cells," said William Guerrant, TSRI Research Associate, and the study's first author. "They also have an impact on inflammatory responses that play a role in tumor growth. It's possible that in other cancers these effects might actually be stronger because of the drug's impact on inflammation."
From their results, the team concluded that celecoxib, like ones commonly used in the treatment of arthritis, may have anti-tumorigenesis effects. And because the drug is already FDA-approved and on the market, they hope clinical trials testing celecoxib on tumors in patients may happen more swiftly. While their study was focused on neurofibromatosis type II, the team is hopeful that the drug will also work in other cancer types with similar biology.
Additional source: The Scripps Research Institute