Analysis of the mechanisms involved in the cell cycle arrest at G2-M phases and possible clinical utility in the field of ginecology.

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15591789
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Obstetrics and gynecology
• Research Institution: Hyogo College of Medicine
• Principal Investigator: MORINAGA Tomonori Hyogo College of Medicine, Faculty of Medicine, Research Associate, 医学部, 助手 (10351818)
• Co-Investigator(Kenkyū-buntansha): TAMAOKI Tomoko (橋本 知子) Hyogo College of Medicine, Faculty of Medicine, Professor, 医学部, 教授 (10172868) ; SHIMA Hiroki Hyogo College of Medicine, Faculty of Medicine, Professor, 医学部, 教授 (90104257) ; TSUJI Yoshiyuki Hyogo College of Medicine, Faculty of Medicine, Associate Professor, 医学部, 助教授 (60148658) ; NAKANO Yoshiro Hyogo College of Medicine, Faculty of Medicine, Research Associate, 医学部, 助手 (30360267) ; YOSHIKAWA Reigetsu Hyogo College of Medicine, Faculty of Medicine, Research Associate, 医学部, 助手 (90319864)
• Project Period (FY): 2003 – 2004
• Keywords: Cell cycle / Mitotic phase / cDNA microarray / Gene expression / Cell death / Cervical cancer

Research Abstract

We observed elongation of cell cycle and accumulation of cells with anomalies in cell division when CaSki human cervical cancer cells were cultured at temperatures lower than usual 37℃. An impaired cell cycle progression at M phase is a possible cause of abnormal chromosome segregation, aneuploidy, cell growth inhibition, and cell death. To investigate the mechanisms involved in these anomalies in cell division, we analyzed changes in gene expression in the cells after the cultivation temperature shift from 37℃ to 32℃ or 30℃, by using a cDNA microarray technique, RT-PCR and western blotting. The results showed that, among those factors related to stress response, ATF2 mRNA was reduced to 60% and 38%, respectively, of the original revel 6 hrs and 12 hrs after the temperature shift. ATF3 expression also was reduced to 75% and 49%, respectively, 6 hrs and 12 hrs after the temperature shift. Expression of both CHOP (C/EBP-homologous protein) and CREB (cAMP responsive element-binding protein)1 gene was suppressed by approximately 40% in 6 to 12 hrs. mRNA of p21^<GP1>, a Cdk inhibitor modulating cell cycle, started to decrease 12 hrs after the temperature shift, and kept repressed until 24 hrs to 72 hrs after the temperature shift. On the contrary, p57^<kip2> expression increased 1.8 fold in 48 hrs. Expression of p53 doubled in 6 hrs, returned to the original revel at 24 hrs, and fallen to 50% at 72 hrs. Expression of MAD2, a factor related to spindle check point, was up regulated 3 fold in 24 hrs in parallel with an increase of M phase cells. Although STK15 (Aurora A) expression declined to 27% 12 hrs after the temperature shift, it elevated to 170% 48 hrs after the temperature change. STK12 expression steadily raised 1.5 fold within 72 hrs after the temperature shift.