A multi-institutional study has revealed that BRAF-positive metastatic malignant melanomas develop resistance to treatment with drugs targeting the BRAF/MEK growth pathway through a major change in metabolism. The findings, which will be published in Cancer Cell and have been released online, suggest a strategy to improve the effectiveness of currently available targeted therapies.
"We were surprised to find that melanoma cells treated with the BRAF inhibitor vemurafenib dramatically change the way they produce energy to stay alive," says David E. Fisher, MD, PhD, chief of Dermatology at Massachusetts General Hospital (MGH) and a co-corresponding author of the Cancer Cell paper. "While current BRAF inhibitor treatment is a major improvement - shrinking tumors in most patients and extending survival for several months - patients eventually relapse. So there is an ongoing need to improve both the magnitude and durability of these responses."
In about half the cases of malignant melanoma - the most deadly form of skin cancer - tumor growth is driven by mutations in the BRAF gene. Research by investigators at the MGH Cancer Center and elsewhere has shown that treatment with drugs that block BRAF activity temporarily halts tumor growth. Combining a BRAF inhibitor with a drug that targets MEK, another protein in the same growth pathway, strengthens and extends the antitumor response. The current study was designed to investigate how BRAF inhibition changes metabolic activity within melanoma cells and to find other possible treatment targets.