Thursday, May 03, 2007

Glycolysis: cancer and heart attacks

Recently Gino talked about an interesting concept at journal club: the Warburg effect. "Because ATP generation through glycolysis is less efficient than through mitochondrial respiration, how cancer cells with this metabolic disadvantage can survive the competition with other cells and eventually develop drug resistance is a long-standing paradox.". This in turn means that hypoxic cells running on glycolysis are more resistant to cytotoxic treatment because of a faulty apoptotic pathway. This effect, surprisingly, may not be limited to cancer cells. Imagine the case of a heart attack. The whole body becomes hypoxic and irreversible damage occurs in the heart and brain tissues. Well it may not be quite so simple. Apparently, researchers were stunned to discover that in fact the cells in the heart shut down and switched to glycolysis but did not die until a few hours had passed. But when we try to resuscitate patients, the sudden influx of oxygen causes a violent switch from glycolysis to the aerobic citric acid cycle, which triggers apoptosis. And so maybe if we could bring oxygen slowly back up we could rescue the heart cells. Alternatively, maybe if we violently brought oxygen to high levels in the tumour we could trigger apoptosis, if their aerobic components are not already defective...