Investigation Of Antitumor Mechanism Of YM155 And Candidate Tumor Marker In Esophageal Squamous Cell Carcinoma

Esophageal cancer is one of most common cancer. The early symptom is hard to detect and the patients are always in state, the 5-years survival is very low. The current standard of care for locally advanced esophageal cancer includes chemotherapy and radiotherapy without surgical treatment; chemotherapy consists of a combination of cis-diamminedichloroplatinum Ⅱ (cisplatin) and 5-fluorouracil. The antitumor effect is still limitation. Accumulating evidence suggest that survivin is overexpression in tumor. Antitumor effect of YM155, a small-molecule survivin suppressant, is significant. However, the action mechanisms of cell death induced by YM155 still remain unknown and need to be further elucidated.In the first part of the dissertation, we found that YM155 can effectively inhibit the proliferation of ESCC cells. S phase accumulation, ROS generation and cell death were observed in ESCC cells treated with YM155. The mechanism research shows that YM155 cause DNA damage, leading PARP-1 activation and PAR formation, AIF translocation,finally inducedESCC cell death in parfhanatos. Furthermore, knock-down of AIF or PARP expression by siRNA significantly attenuated cell death in ESCC cells. It means that PARP-1 and AIF play a very important role inparthanatos.Expression profile analysis identified 230 up-regulated genes and 190 down-regulated genes in KYSE 410 cells treated withYM155. These differentially expressed genes were involved in several signaling pathways associated with cell cycle regulation and cellular metabolism.It gave an evidence thatYM155 did not infulence cell apoptosis associated genes.Xenograft model showed that YM155 can inhibite tumor growth. Our results provide a mechanism that YM155 induced PARP-mediated parfhanatos, for future clinical investigation of the therapeutic efficacy of YM155 in patients with esophageal cancer.In the second part of the dissertation, based on previous differential proteinomic results which stathmin was as a candidate tumor marker in ESCC. We validated the expression of Stathmin in serum. Firstly, in 74 ESCC patients and 81 healthy controls, the level of serum Stathmin in ESCC patients(6.9±0.44ng/mL) was significantly higher than that in healthy controls(0.73±0.06ng/mL;P<0.0001). The level of serum Stathmin was correlated with lymph node metastasis(P=0.036). Secondly, the sensitivity and specificity of serum Stathmin were significantly higher than other tumor marker such as Cyfra21-1、CEA、CA72-4 and CA19-9 in esophageal squamous cell carcinoma. We expanded further samples to 535 ESCC vs 288 healthy control. Our data showed that the serum Stathmin in ESCC patients (5.98±2.89 ng/mL) is still significantly higher than that in healthy controls(2.16±1.19ng/mL, P<0.0001), The expression of Stathmin was significantly correlated with lymph node metastasis(P=0.029) and tumor size(P=0.046). We can draw a conclusion that Stathmin can be used as an important marker to indicate the aided diagnosis in esophageal cancer cell.