In lab tests, the peptide bremelanotide (also known as melanotan‑I) was able to kill glioblastoma brain‑cancer cells by lowering a protein called survivin, without harming normal human cells. The effect depended on activating specific melanocortin receptors (MC3 and MC4) and could boost the killing power of standard chemo drugs.

Glioblastoma is the most aggressive form of brain tumor and has a dismal prognosis; therefore, novel therapeutic approaches based on the mechanisms underlying its aggressive nature are urgently required. A growing body of evidence suggests that neurotransmitters play a key role in modulating the biology of glioblastoma; however, the role of melanocortins remains unclear. The effects of bremelanotide, a melanocortin receptor agonist, alone or in combination with chemotherapeutic agents, on survivin expression and cell viability were investigated in human glioblastoma cell lines. Bremelanotide reduced survivin expression and induced cell death in glioblastoma cells at concentrations that were not toxic to normal human cells, and both of these effects were canceled in the presence of an antagonist of melanocortin receptors 3 and 4. Bremelanotide-induced cell death was prevented by the forced over-expression of survivin in glioblastoma cells, suggesting that bremelanotide induces glioblastoma cell death by inhibiting the expression of survivin. Bremelanotide also promoted cell death induced by chemotherapeutic agents, such as temozolomide and osimertinib. The present results identified melanocortin receptors 3 and 4 as novel and viable therapeutic targets for glioblastoma. Activation of these receptors by bremelanotide may inhibit the expression of survivin, thereby sensitizing glioblastoma cells to cell death.