Dynamic Study On Circadian Rhythm Variation Of The Clock Genes Per1, Per2 And Cell Cycle Related Genes In Different Stages Of Carcinogenesis In Buccal Mucosa

Objective:To investigate the expression and circadian rhythm variation of biological clock gene Perl,Per2 and cell cycle genes p53, CyclinD1, CDK1, CyclinB1,Wee1 in different stages of carcinogenesis in buccal mucosa and its relationship with the development of buccal mucosa carcinoma.Method:ninety Syria golden hamsters were housed under 12 h light-12 h dark cycles,3 weeks later, the model of buccal squamous cell carcinoma was established by using the dimethylbenzanthracene(DMBA) acetone solution to smear the golden hamster buccal mucosa. Before the DMBA acetone solution was used and after DMBA was used 6 weeks and 14 weeks respectively, the golden hamsters were sacrificed at 6 different time points (5 rats per time point) within 24h, including 4,8,12,16,20 and 24 HALO (hour after lights onset, HALO),and the normal buccal mucosa, precancerous lesions and cancer tissue were obtained, respectively. HE stained sections were prepared to observe the canceration of each tissue; Real time RT-PCR was used to detect the mRNA expression of Per1, Per2, p53, CyclinD1, CDK1, CyclinB1 and Wee1, and a cosine analysis method was applied to determine the circadian rhythm variation of Per1, Per2, p53, CyclinD1, CDK1, CyclinB1 and Wee1 mRNA expression, which were characterized by median, amplitude and acrophase.Result:The expression of Per1, Per2, p53, CDK1, CyclinD1 and Wee1 mRNA in 6 different time points within 24h in the tissues of three different stages of carcinogenesis had circadian rhythm, respectively. However, the CyclinBl mRNA was expressed with circadian rhythm just in normal and cancer tissue (P<0.05), while in precancerous lesions tissues the circadian rhythm was disorder (P>0.05). As the development of carcinoma, the median of Perl, Per2 and p53 mRNA expression were significantly decreased (P<0.05),yet the median of CDK1, CyclinBl,CyclinDl and Wee1 mRNA expression were significantly increased (P<0.05); The amplitude of Perl, Per2, p53 and CyclinDl mRNA expression were significantly decreased as the development of carcinoma (P<0.05), however the amplitude of CDK1 and Weel mRNA expression was significantly increased (P<0.05), in addition, there were no significantly difference in the amplitude of CyclinB1 mRNA expression; The time that the peak expression value appears (Acrophase) of Perl, Per2, CDK1 and Wee1 mRNA in precancerous lesion tissues were remarkably earlier than that in normal tissues, in contrast, the acrophase of p53 and CyclinDl mRNA expression were remarkably delayed. Moreover, the acrophase of CDK1, CyclinBl and Weel mRNA expression in cancer tissues were obviously earlier than that in normal tissues, yet there were no significantly variation in acrophase of Per1, Per2, p53, CyclinD1 mRNA expression between normal tissues and cancer tissues.Conclusion:The circadian rhythm of clock gene Per1, Per2 and cell cycle genes p53, CyclinD1, CDK1, CyclinB1 and Wee1 expression were remarkably varied as the occurrence and development of carcinoma. Therefore, it is significant to explore about the interaction between circadian rhythm and cell cycle, and their relationship with the occurrence and development of cancers in depth, which may provide us new idea and method for further investigation of the carcinogenesis, development, and individualized treatment of carcinoma.