Upstream binding factor up-regulated in hepatocellular carcinoma is related to the survival and cisplatin-sensitivity of cancer cells

Upstream binding factor (UBF) is an RNA polymerase I- specific transcription factor. By representational difference analysis, Northern blot, and cDNA array analysis, up- regulation of UBF was detected in 12 of 17 clinical hepatocellular carcinoma samples comparing to the paired normal liver tissues. Introduction of UBF in human lung fibroblast cells that do not express UBF resulted in an accelerated rate of cell growth; on the other hand, antisense oligode-oxynucleotides (ODNs) treatment of UBF- expressing hepatoma cell lines reduced the level of UBF protein, suppressed the colony formation capacity of these cells on soft agarose, and finally caused cell death. Annexin V binding analysis suggested that anti- UBF ODN-caused cell death might involve weak apoptosis, however, DNA laddering and cleavage of poly (ADP- ribose) polymerase were not observed in these ODN- treated cells. Expression profiling of the anti- UBF ODN-treated cells using a human cDNA array revealed that the expression of 30 genes was altered in response to the inhibition of UBF expression. Notably, UBF expression could increase the cell sensitivity to the chemotherapeutic reagent cis- diaminedichloroplatinum (II). We proposed that UBF is fundamental to the survival of cells expressing the gene, and is potential as a target for screening anti- cancer drugs and an indicator in selecting chemotherapeutic reagents.