Expression And Clinical Impact Of SYF2 In Esophageal Squamous Cell Carcinoma

Objective1. To investigate the expression of SYF2 in humanesophageal squamouscell carcinoma(ESCC), and analyze the correlation of abnormal SYF2 expression and the occurrence and development of ESCC.2. To investigate the expression variation of SYF2 during the proliferation process of ESCC cell line ECA109 and TE1 cells by serum starvation and release experiment, and investigate the role of SYF2 during the process. To futher reveal the molecular pathogenesis of ESCC, and hope to provide the new target for therapy of ESCC.Methods1. The expressions of SYF2 and PCNA(the proliferation index) in 8 cases of fresh frozen specimens from ESCC and the adjacent non-tumor esophageal tissues were detected by Western blot. The expressions of SYF2 and Ki-67(the proliferation index) were detected immunohistochemically in 90 samples of ESCC tissues and adjacent non-tumor esophageal tissues. The correlation between SYF2 and clinicopathologic parameters was analyzed in ESCC patients, such as age, gender, histological grade, metastasis and so on. Ninety cases of ESCC patients were followed up and survival curve was calculated using the Kaplan-Meier method. The prognosis was analyzed with the univariate and multivariate Cox proportional hazards regression analysis.2.ECA109 and TE1 cells were treated with serum sarvationa and release for synchronization and the cell cycles were detected by flow cytometer. Western blot was performed to detect the expression variation of SYF2, PCNA and cyclin D1 in ECA109 and TE1 cells during serum starvation and release process.3. Cell cycle was detected by flow cytometer after SYF2 expression was down-regulated by transfected with siSYF2, and the expressions of SYF2, PCNA and cyclin D1 were detected by Western blot. CCK8 and colony formation assays were used to detect the proliferation of ESCC cells.4. The alteration of SYF2 after treatment with cisplatin and the resistance to cisplatin was studied after SYF2 was knocked down.Results1.Immunohistochemistry and Western blot analysis showed that SYF2 expression in ESCC were higher than that in non-tumor liver tissue. SYF2 expression was correlated with histological grade(P=0.000) and Ki-67(P=0.001). The Kaplan-Meier survival curves showed that high SYF2 expression related to a poor survival with statistical significance(P<0.01). Unvaried analysis showed that SYF2 expression was associated with poor prognosis of ESCC(P=0.002). Multivariate Cox proportional hazards regression analysis indicated that SYF2 expression was an independent prognostic marker for ESCC(P=0.005).2. The cell cycle of ECA109 and TE1 cells was blocked by serum starvation with the down-expression of SYF2. Meanwhile, the expressions of PCNA and cyclinD1 were simultaneously down-regulated. The ECA109 and TE1 cells reentered the cell cycle after serum release and the reverse changes of these proteins were observed. We found that down-expression of SYF2 by transfected with siSYF2 inhibited proliferation in ECA109 and TE1 cells.3. Knockdown of SYF2 was found to block the cell cycle of ECA109 and TE1 cells, meanwhile down-regulatethe expression of PCNA and cyclinD1.CCK8 and colony formation assaysshowed knockdown of SYF2 inhibited the proliferation of ESCC cells.4. The proliferation of ESCC cells was inhibited upon the treatment of cisplatin. The resistance to cisplatin decreased after knocking down SYF2 in ESCC cell lines.Conclusions1. The expression of SYF2 was upregulated in ESCC and it is an independent prognostic indicator of overall survival, suggesting that SYF2 may play a role in the oncogenesis and development of ESCC. SYF2 may be a new prognostic marker for ESCC.2. SYF2 might contribute to the progression of ESCC by regulating the cell cycle. Knocking down SYF2 decreasedthe resistance of ESCC cell lines to cisplatin. These results indicate that SYF2 may be a potential target for treating ESCC.