Gene expression profile of human epidermoid carcinoma KB cells that overexpress thymidine phosphorylase

Thymidine phosphorylase (TP) catalyzes the reversible phosphorolysis of thymidine, deoxyuridine, and their analogs to the respective bases and 2-deoxy-D-ribose-1-phosphate. TP is identical to platelet-derived endothelial cell growth factor (PD-ECGF). TP was reported to induce many angiogenic factors. However, the molecular mechanism of the TP function is still obscure. To elucidate the molecular basis for the TP function in human epidermoid carcinoma KB cells, we performed a whole genome-wide microarray analysis. Genes upregulated in KB cells overexpressing TP are supposed to represent potential molecular targets of TP in KB cells. KB cells (4 × 10^5) in 5 ml of culture media were cultured for 24 hours, then the growth medium was replaced with serum-free medium. These cells were maintained at 37 ˚C in a humidified atmosphere of 5% CO2 for 12 hours, then these cells were collected for RNA extraction and quantification of the transcripts by microarray analysis.