[ExI] Calorie restriction assists chemotherapy
pharos at gmail.com
Tue Apr 1 12:21:20 UTC 2008
Good news for Spike!
Doctors who treat patients with cancer have a balancing act. They give
too little chemotherapy and tumors survive, but too much can be life
threatening. Now researchers have found that in a series of lab tests,
not eating for 48 hours gave healthy cells an edge. University of
Southern California Associate Professor of Gerontology and Biological
Science Valter Longo says, "The cancer cells have this oncogene, have
these mutations that keep them always on. So, they basically are
unable to obey the starvation dependent order. Starvation tells
[healthy cells] to go into protective mode. The cancer cells, because
of their characteristics of not being able to respond to that, just
continue on their normal pro-growth track."
Strategies to treat cancer have focused primarily on the killing of
tumor cells. Here, we describe a differential stress resistance (DSR)
method that focuses instead on protecting the organism but not cancer
cells against chemotherapy. Short-term starved S. cerevisiae or cells
lacking proto-oncogene homologs were up to 1,000 times better
protected against oxidative stress or chemotherapy drugs than cells
expressing the oncogene homolog Ras2val19. Low-glucose or low-serum
media also protected primary glial cells but not six different rat and
human glioma and neuroblastoma cancer cell lines against hydrogen
peroxide or the chemotherapy drug/pro-oxidant cyclophosphamide.
Finally, short-term starvation provided complete protection to mice
but not to injected neuroblastoma cells against a high dose of the
chemotherapy drug/pro-oxidant etoposide. These studies describe a
starvation-based DSR strategy to enhance the efficacy of chemotherapy
and suggest that specific agents among those that promote oxidative
stress and DNA damage have the potential to maximize the differential
toxicity to normal and cancer cells.
Further research required (of course), but it looks like 48 hours
starvation before chemotherapy helps the chemo to attack the cancer
cells more than normal cells.
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