Critical protein for cancer cell growth found

Researchers at the Walter and Eliza Hall Institute have discovered a cellular protein that is important for keeping cancer cells alive and is thus a suitable target for treatment. Their results have been published in the journal Genes & Development.

Up to 70% of human cancers have deregulated MYC expression - that is, unusually high levels of the protein MYC - which causes cancerous changes in cells by forcing them into abnormally rapid growth. A research team led by Dr Gemma Kelly, Dr Marco Herold and Professor Andreas Strasser investigated how cells with high levels of MYC stay alive and grow.

“Specifically in this work we looked at lymphoma cells that had deregulated MYC expression and we carried out some research to determine which of the proteins were key for the sustained growth of the tumour cells,” said Dr Kelly. “What we found was that there was one particular protein called MCL-1 which was absolutely critical to keep these cancer cells alive and allow them to grow.” Once this protein was disabled, she said, the lymphoma cells were more sensitive and easier to kill.

Professor Strasser noted that “in many of these tumours, even a 50% reduction could achieve a long-term remission … [therefore] the development of drugs that either directly attack MCL-1 or affect its level of expression might actually achieve quite a lot in cancer therapy”. Furthermore, he said, the treatment should not cause too many side effects in normal tissues.

Dr Kelly said the discovery builds on years of research at the institute, with the researchers having been aware that “proteins from the BCL-2 protein family enhance cell survival and cooperate with MYC to accelerate the development of cancer”, but unaware of which specific protein was most important.

“Anticancer agents that target the protein BCL-2, which is closely related to MCL-1, are already showing promise in clinical trials,” added Professor Strasser. “We are hopeful that inhibitors of MCL-1 will soon become available for clinical testing.”

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