A molecular geneticist at Montana State University has discovered a unique survival mechanism in mammalian cells that allows them to produce cysteine, an essential amino acid, even when their usual systems for generating it are nonfunctional. This revelation challenges long-held views in biology, which posited that functioning disulfide reductase systems were crucial for all living cells.
The research, detailed in Nature Chemical Biology, could lead to new strategies to enhance cancer treatment by exploiting this survival pathway. Ed Schmidt, the lead author, explained that cysteine is critical for various cellular functions, including protein synthesis and protection against damage. Traditionally, it was believed that cells could not access cysteine externally, necessitating internal production from cystine, its oxidized form.
The breakthrough came after Schmidt’s team observed a colony of genetically engineered mice surviving conditions believed to be lethal due to a lack of cysteine production mechanisms. This led to the exploration of alternative pathways for cysteine acquisition, ultimately identifying a previously overlooked method where a carbon-sulfur bond in cystine is cleaved, releasing usable cysteine.
This alternative pathway may have initially evolved as a defense against environmental toxins, providing an advantage to early multicellular organisms. Interestingly, while this mechanism aids healthy cells, it may also allow some cancer cells to endure treatments like chemotherapy and radiation, signaling potential new avenues for making cancers more susceptible to therapies by targeting this backup system.
The research involved contributions from several Montana State University students and collaborations with international researchers, showcasing the significant role of student engagement in advancing scientific discovery.
