Jianxin Zhong

Ubiquitin-specific protease 14 (USP14) regulates cellular proliferation and apoptosis in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. Thus, there is an emergent need to invest a novel therapeutic for EOC. In this study, we defined ubiquitin-specific protease 14 (USP14) as a therapeutic target for EOC. Western blot was used to evaluate the expression of USP14 in nine fresh EOC tissues and three fresh normal ovarian tissues. The protein level of USP14 was higher in the cancer samples compared with that in the normal ovary tissues. Immunohistochemistry analysis was performed on formalin-fixed paraffin-embedded section of 116 cases of EOCs and indicated that USP14 was significantly associated with clinical pathologic variables. Kaplan–Meier curve showed that high expression of USP14 was related to poor prognosis of EOC patients. Starvation and re-feeding assay was used to imitate cell cycle, suggesting that USP14 played a critical role in SKOV3 cell proliferation. CCK-8 assay showed that SKOV3 cells treated with USP14-shRNA (shUSP14) grew more slowly than control group. Flow cytometry revealed that the reduced expression of USP14 induced the apoptosis of the SKOV3 EOC cells. In summary, our findings suggest that USP14 is involved in the progression of EOC and that it may be a useful target of therapy in EOC.

Expression and clinical role of TCTP in epithelial ovarian cancer

The aim of this study is to investigate the potential role and prognostic significance of translationally controlled tumor protein (TCTP) in human epithelial ovarian cancer (EOC). Western blot was used to evaluate the expression of TCTP in eight fresh EOC tissues. Immunohistochemistry was performed on formalin-fixed paraffin-embedded sections of 119 cases of ovarian cancers. Kaplan–Meier method indicated the relation between TCTP and EOC patients’ overall survival rate. Starvation and re-feeding was used to assess cell cycle. Knocking down of TCTP and CCK8 assay showed the role of TCTP in HO8910 cell cycle. We found that TCTP was overexpressed in carcinoma tissues compared with normal tissues. Immunohistochemistry revealed that TCTP expression was significantly associated with clinicopathologic variables. Kaplan–Meier analysis revealed that high TCTP expression was significantly related to poor prognosis of the patients. Starvation and re-feeding suggested TCTP played a critical role in HO8910 cell proliferation. Interference of TCTP and CCK8 assay showed that the TCTP-siRNA treated HO8910 cells grew more slowly than the control group. CCK-8 assays and terminal-deoxynucleoitidyl transferase mediated nick end labeling assays were also performed to demonstrate the cisplatin could inhibit the survival of HO8910 cells and promote their apoptosis. All the experiments we have done showed that TCTP could promote the progression of EOC and reduce the sensitiveness of HO8910 cells to cisplatin.

CAP1 is overexpressed in human epithelial ovarian cancer and promotes cell proliferation.

Adenylate cyclase-associated protein 1 (CAP1) regulates both actin filaments and the Ras/cAMP pathway in yeast, and has been found play a role in cell motility and in the development of certain types of cancer. In the present study, we investigated CAP1 gene expression in human epithelial ovarian cancer (EOC). Western blot analysis and immunohistochemistry were performed using EOC tissue samples and the results revealed that CAP1 expression increased with the increasing grade of EOC. In the normal ovarian tissue samples however, CAP1 expression was barely detected. Using Pearson’s χ2 test, it was demonstrated that CAP1 expression was associated with the histological grade and Ki-67 expression. Kaplan-Meier analysis revealed that a higher CAP1 expression in patients with EOC was associated with a poorer prognosis. In in vitro experiments using HO-8910 EOC cells, the expression of CAP1 was knocked down using siRNA. The proliferation of the HO-8910 cells was then determined by cell cycle analysis and cell proliferation assay using the cell counting kit-8 and flow cytometry. The results revealed that the loss of CAP1 expression inhibited cell cycle progression. These findings suggest that a high expression of CAP1 is involved in the pathogenesis of EOC, and that the downregulation of CAP1 in tumor cells may be a therapeutic target for the treatment of patients with EOC.

The expression of CDK1 is associated with proliferation and can be a prognostic factor in epithelial ovarian cancer.

Overexpression of cyclin-dependent kinase 1 (CDK1) has been noted to correlation with several human cancers. However, the effects of CDK1 on ovarian cancer development remain unclear. The aim of this study was to examine the effect of CDK1 and related mechanism in the proliferation and resistance to chemotherapeutic drugs of epithelial ovarian cancer (EOC). Immunohistochemical analysis was performed in 119 human ovarian cancer samples, and the data were correlated with clinicopathologic features. Furthermore, Western blot analysis was performed for CDK1 in EOC samples and cell lines to evaluate their protein levels and molecular interaction. Kaplan-Meier survival analysis showed that strong expression of CDK1 exhibited a significant correlation with poor prognosis in human EOC (P = 0.02). Meanwhile, we found that knockdown CDK1 by shCDK1 promoted the apoptosis rate and increased the sensitivity to chemotherapy drugs. Thus, CDK1 might serve as a prognostic marker, and it might be of great value for experimental therapies in EOC.

PFTK1 regulates cell proliferation, migration and invasion in epithelial ovarian cancer

PFTK1, also named Cyclin-Dependent Kinase 14 (CDK14), is a member of the cell division cycle 2 (CDC2)-related protein kinase family. It is a serine/threonine-protein kinase involved in the regulation of cell cycle progression and cell proliferation. In this study, we investigated the role of PFTK1 in epithelial ovarian cancer (EOC) development. The expression of PFTK1 was detected by Western blot and immunohistochemistry staining, both of which demonstrated that PFTK1 was overexpressed in EOC tissues and cells. Statistical analysis showed the expression of PFTK1 was associated with multiple clinicopathological factors, including tumor grade, FIGO stage, lymph node metastatis, Ki-67 expression and predicted a poor prognosis of EOC patients. With in vitro studies we found that PFTK1 expression was decreased in serum-starved ovarian cancer cells, and progressively increased after serum-re-feeding. Knocking PFTK1 down by small interfering RNA (siRNA) significantly inhibited ovarian cancer cell proliferation, migration and invasion. Taken together, our study suggested that PFTK1 played an important role in ovarian cancer development.

High expression of CDC6 is associated with accelerated cell proliferation and poor prognosis of epithelial ovarian cancer.

Cell division cycle 6 (CDC6) is an essential regulator of DNA replication and plays important roles in the activation and maintenance of the checkpoint mechanisms in the cell cycle. CDC6 has been associated with the oncogenic activities in human cancers, but the biological function and clinical significance of CDC6 in EOC remain unclear. The aim of the present study is to examine the effect of CDC6 on epithelial ovarian cancer (EOC) cells proliferation. We found that CDC6 protein level was up-regulated in EOC tissues compared with the normal ovary tissues. CDC6 expression correlated significantly with FIGO stage (p<0.001), differentiation grade (p=0.002), ascites (p<0.001), malignant tumor cells in ascites (p=0.004), and lymph node status (p<0.001). In vitro, after the release of ovarian cancer cell line (HO8910) from serum starvation, the expression of CDC6, cyclinD1, and PCNA was up-regulated, whereas p16 expression was down-regulated. Furthermore, down-regulation of CDC6 in HO8910 cells decreased cell proliferation and colony formation. HO8910 cells transfected with sh CDC6#1 underwent G1 phase cell cycle arrest. Collectively, this study provides a novel regulatory signaling pathway of CDC6-regulated EOC growth and a new potential therapeutic target for EOC patients.

Expression of Sam68 Correlates With Cell Proliferation and Survival in Epithelial Ovarian Cancer.

Src associated in mitosis, 68 kDa (Sam68) is a KH domain RNA-binding protein that belongs to the signal transduction and activation of RNA family. It is a multifunctional protein known to regulate cellular signal transduction, transcription, RNA metabolism, proliferation, and apoptosis, thus implicated in tumor growth. Herein, we investigated the clinical significance of Sam68 in human epithelial ovarian cancer (EOC). Western blot and immunohistochemical staining demonstrated that Sam68 expression was upregulated in EOC tissues and cell lines. Statistical analysis showed that high expression of Sam68 correlated with poor prognosis of patients with EOC. In vitro, serum starvation-refeeding experiment was primarily performed to confirm that Sam68 participated in the cell cycle progression of EOC cell lines. Then knocking down Sam68 level with small interfering RNA, cell cycle was arrested at G1 phase and cell proliferation impaired. Furthermore, we demonstrated that the antiproliferative effect of silencing Sam68 in EOC cells was associated with the upregulation of cyclin-dependent kinase inhibitors p21Cip1 and p27Kip1, along with the downregulation of p-FOXO3a, p-Akt, and p-GSK-3β. Taken together, our findings uncovered that Sam68 played an important role in promoting the proliferation of human ovarian cancer, thereby might be a novel therapeutic target for EOC.

SYF2 is upregulated in human epithelial ovarian cancer and promotes cell proliferation

SYF2 is reported to be as a cell cycle regulator at the G1/S transition and encodes a nuclear protein that interacts with cyclin-D-type binding protein 1. In our study, we investigated the role of SYF2 in human epithelial ovarian cancer (EOC) progression. Western blot and immunohistochemistry analysis displayed that SYF2 was overexpressed in EOC tissues and EOC cell lines. In addition, the immunoreactivity of SYF2 was positively correlated with tumor grade and Ki-67 expression. In vitro, serum starvation-refeeding experiment and SYF2-siRNA transfection assay demonstrated that the expression of SYF2 was promoted in the proliferative progression of EOC cells, while knockdown of SYF2 expression decreased and inhibited cell growth rate of EOC cells. With all the results, we support that SYF2 might contribute to EOC progression via modulation of proliferation in EOC cells and would provide a novel therapeutic target of human EOC.