Study wrapper · #328
Melanocortin Receptor Agonist Bremelanotide Induces Cell Death and Growth Inhibition in Glioblastoma Cells via Suppression of Survivin Expression.
Editor's note
This is an in-vitro cancer study exploring a repurposing idea entirely unrelated to bremelanotide's approved use. In human glioblastoma cell lines, bremelanotide reduced expression of survivin (a protein that helps cancer cells resist death) and triggered cell death at concentrations reported as non-toxic to normal human cells; blocking MC3R/MC4R abolished the effect, and forcing survivin expression rescued the cells — a reasonably coherent mechanistic chain. It also appeared to augment killing by the chemotherapies temozolomide and osimertinib. These are cell-culture findings only: no animal or human data, no pharmacokinetics showing the drug reaches brain tumors at active concentrations, and glioblastoma cell lines are an imperfect model. The signal is interesting and mechanistically specific, but it is early and should not be read as evidence that bremelanotide has any role in cancer. These are preclinical in-vitro findings; animal and human studies would be required before any clinical conclusions could be drawn.
Plain-language abstract
Glioblastoma is an aggressive brain cancer with poor outcomes, so researchers are searching for new ways to attack it. This laboratory study tested bremelanotide — a melanocortin-receptor drug — on human glioblastoma cells grown in dishes. The researchers found that bremelanotide lowered levels of survivin, a protein that helps cancer cells avoid dying, and caused the cancer cells to die, while sparing normal human cells at the same concentrations. When they blocked the melanocortin receptors (types 3 and 4), the effect disappeared, suggesting the drug worked through those receptors. When they artificially boosted survivin, the cancer cells survived, supporting the idea that lowering survivin was how the cells were killed. Bremelanotide also increased cancer-cell death caused by two chemotherapy drugs, temozolomide and osimertinib. The authors suggest melanocortin receptors could be a new target for glioblastoma. Importantly, this was done entirely in cells in the laboratory — not in animals or people — so it does not show that bremelanotide helps against brain cancer. Much more testing would be required before any such conclusion.