An all-female research team from the University of the Philippines Marine Science Institute (UP MSI) recently published a study proposing what could be a promising treatment option for metastatic breast cancer.
These scientists demonstrated that the potent compound renieramycin M (RM) derived from the Philippine blue sponge (Xestospongia sp.), especially when combined with the clinically used cancer drug doxorubicin (Dox) — significantly shrank tumors in mice while reducing the toxicity commonly associated with chemotherapy drugs.
The team is composed of Dr. Gisela P. Concepcion, Dr. Lilibeth Salvador-Reyes, Zildjian Acyatan, Shalice Susana-Guevarra, Myra Ruth Picart, and Eliza Belen.
They hypothesized that RM, which independently triggers programmed cell death in cancer cells, could work synergistically with Dox to enhance its cancer-fighting effects. Although previous in vitro studies supported this theory, further testing in living organisms was needed.
The team conducted the study by purifying RM using a method developed by their collaborators from Chulalongkorn University and Meiji Pharmaceutical University and obtaining doxorubicin commercially. They used 4T1 mouse mammary tumor cells, a well-established model for advanced-stage, triple-negative human breast cancer.
While observing strict animal-care protocols, the researchers injected mice with 4T1 cells, tested different doses of Dox and RM (both individually and in combination), and then monitored tumor growth daily for a month.
Their significant findings include reducing tumor size by 46.53 percent by day 21, outperforming other treatment groups, including those receiving Dox or RM alone.
Meanwhile, the team tracked the mice’s weight, behavior, and lifespan to assess drug toxicity. While doses of Dox and RM alone resulted in the highest fatality rates, the combination therapies showed lower toxicity.
Thanks to the study, RM-Dox combinations could pave the way for more effective and less harmful therapies.
The researchers, however, concluded that further studies including clinical trials need to be done before RM-based treatments can be used in human patients.