BMSC enhance the survival of paclitaxel treated squamous cell carcinoma cells in vitro.

The 5-year survival rate of patients suffering from head and neck squamous cell carcinoma (HNSCC) is unsatisfying despite the advances in carcinoma treatment. Recent studies suggest that stem cells can be used as a gene therapy carrier for cancer treatment. Stem cells produce different cytokines such as growth factors in a paracrine manner and cancer cells may show drug resistance in the presence of such growth factors. Reports in the literature concerning treatment of cancer using bone marrow derived stem cells (BMSC) are controversial, which led us to investigate the effects of paclitaxel on human HNSCC cell lines (FaDu and HLaC 78) cultivated simultaneously with BMSC in a transwell system (co-culture). Co-culture and HNSCC cell lines were treated with 10nM of paclitaxel for 24h. Morphology, viability and apoptosis were measured by microscopy, the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and the Annexin V-propidium iodide test. The survival of HNSCC cell lines treated with paclitaxel in co-culture increased significantly compared to control cells. Apoptosis of HNSCC cell lines in co-culture was attenuated significantly. In conclusion, BMSC increase HNSCC resistance to treatment with paclitaxel in vitro. Tumor-stroma interactions are critical components of tumor biology including tumor invasion and metastatic potential. Therefore particular attention must be paid to the complex tumor-stroma interactions to fully understand how tumor cells become chemoresistant.