Identification of a novel role of Septin 10 in paclitaxel-resistance in cancers through a functional genomics screen.

Paclitaxel (also known as taxol) is a member of the taxane class of anticancer agents, which has a well-known mechanism that blocks cell mitosis and kills tumor cells, that is often used in clinics to treat cancer. However, some carcinomas such as breast, ovarian and non-small-cell lung cancers are often resistant to paclitaxel treatment. In this study, we used a lentiviral siRNA library against the entire human genomes to identify genes associated with sensitivity to paclitaxel. We isolated two paclitaxel-resistant clones carrying the siRNA specific to septin 10 (SEPT10) and to budding uninhibited by benzimidazoles 3. The relation of budding uninhibited by benzimidazoles 3 to paclitaxel sensitivity has already been established, but that of SEPT10 remains unknown. Interestingly, overexpression of SEPT10 increased cells' sensitivity to paclitaxel; we also found that SEPT10 is an important regulator for microtubule stability. Furthermore, we found that paclitaxel-resistant tumors had decreased expression of SEPT10. Thus, SEPT10 may be a novel candidate molecule that acts as a good indicator of paclitaxel-resistant carcinomas.