OBJECTIVETo investigate the changes of gene expression profile in transitional cell carcinoma of bladder T24 cell after crocin treatment, in order to find the possible crocin targets.

METHODThe bladder cancer T24 cell line was treated with crocin. MTT assay was adopted to determine the inhibition rate for selecting the best effect time and concentration of crocin. Differentially expressed genes on groups with or without treatment of crocin were screened with high throughout cDNA microarray. One up-regulated gene p21(WAF1) and one down-regulated gene cyclinD1 were selected to undergo analysis by the reverse transcription polymerase chain reaction (RT-PCR). Moreover, immunocytochemical method was used to evaluate p21(WAF1) and cyclinD1 protein expression.

RESULTThe growth of T24 cells was inhibited remarkably following a marked positive correlation between crocin concentration, time and inhibitor rate. When 3 mmol x L(-1) crocin treated T24 cells for 48h, the difference was significant compared with the control group (P < 0.05). Crocin induced wide changes of the gene expression profile of T24 cells. A total of 836 genes were up-regulated or down-regulated by more than 2 times, which were involved cell cycle controlling, DNA cell apoptosis, replication factor, and so on. The mRNA expression of p21(WAF1) and cyclinD1 detected by RT-PCR were in accordance with cDNA microarray data. The results of immunocytochemical method showed that p21(WAF1) and cyclinD1 protein expression were consistent with those mRNA expression.

CONCLUSIONCrocin can induce the significant alteration of gene expression profile of T24 cell. It is suggested that the widly konwn anti-tumor effects of crocin are medicated at least in part by regulating the cell cycle controlling gene expression.