Acute vincristine pretreatment protects adult mouse cardiac myocytes from oxidative stress.

Vincristine is a chemotherapeutic agent that disrupts microtubules. We noted that paclitaxel (Taxol), which stabilizes microtubules, protected cultured adult mouse cardiac myocytes from oxidative stress induced by H(2)O(2). We hypothesized that vincristine, which disrupts microtubules, should have the opposite effect. To our surprise, we found that pretreatment with concentrations of vincristine ranging from 30 to 120 micromol/L for 60 min preserved myocyte viability and morphology after incubation with 30 micromol/L of H(2)O(2) for 35 min as measured by trypan blue exclusion. The cardioprotective effects of vincristine were also observed during prolonged hypoxia. With continuous exposure to vincristine, survival lasted for as long as 24 h, but longer periods of exposure up to 42 h resulted in extensive cell death. Despite microtubule disruption evidenced on deconvolution microscopy, vincristine activated a prosurvival pathway resulting in increased phosphorylation of Akt, ERK and GSK-3beta and in reduced cytochrome C release into the cytosol. Pharmacological inhibitors of Akt and Erk attenuated the cardioprotective effect of vincristine. We conclude that short-term pretreatment with vincristine exerts dramatic protective effects in cultured adult mouse myocytes subjected to acute oxidative stress. Despite causing microtubule disruption, vincristine initiates a prosurvival signaling pathway. As vincristine and doxorubicin are often used in conjunction to treat patients, it is possible that vincristine could be used to modify the cardiotoxicity of doxorubicin.