Severe cellular stress activates apoptosis independently of p53 in osteosarcoma.

Apoptosis induced by doxorubicin, bortezomib, or paclitaxel, targeting DNA, 26S proteasome, and microtubules respectively, was assessed in two osteosarcoma cells, p53 wild-type U2OS and p53-null MG63 cells. Doxorubicin-induced apoptosis only occurred in U2OS, not in MG63. In contrast, bortezomib and paclitaxel could drive U2OS or MG63 toward apoptosis effectively, suggesting that apoptosis induced by bortezomib or paclitaxel is p53-independent.