ABSTRACT
Nasopharyngeal carcinoma (NPC), a malignant tumor at the top and side of the nasopharyngeal cavity, highly occurs in the southern region of China. Cancer cell metastasis is one of the leading causes of death in NPC patients. Osteopontin (OPN), is a phosphorylated extracellular matrix protein with a variety of functions, was found to be overexpressed in many cancers. However, the expression and role of OPN in patients with NPC in Guangxi, China are unclear. Here, we observed that NPC patients had upregulated OPN at mRNA protein and levels. Immunochemistry (IHC) analysis of OPN expression in 68 NPC clinical specimens indicated that high expression of OPN had positive correlation with NPC lymph node metastasis (P = 0.012), distant metastasis (P = 0.001) and TNM staging (P = 0.018). Moreover, compared with relatively low OPN, NPC patients with higher expression of OPN showed a poorer overall survival rate (P = 0.001, log rank test). Multivariate analysis showed that OPN expression in NPC was an independent prognostic marker. The proliferation, apoptosis and migration ability of CEN-2Z cancer cells in NPC were determined by MTT, flow cytometry and wound-healing assays, respectively. Upregulation of OPN in CEN-2Z cancer cells promoted cancer cell proliferation and migration, and suppressed apoptosis. In sum, our result suggests OPN could be used as a valuable oncoprotein and show that overexpression of OPN in NPC may serve as a potential prognostic marker.
Subject(s)
Carcinoma/metabolism , Cell Proliferation , Nasopharyngeal Neoplasms/metabolism , Osteopontin/metabolism , Apoptosis , Carcinoma/mortality , Carcinoma/pathology , Humans , Kaplan-Meier Estimate , Lymphatic Metastasis , Nasopharyngeal Carcinoma , Nasopharyngeal Neoplasms/mortality , Nasopharyngeal Neoplasms/pathology , Neoplasm Staging , Prognosis , RNA, Messenger/metabolism , Tumor Cells, Cultured , Up-RegulationABSTRACT
OBJECTIVE: To assess the effect of small interfering RNA (siRNA)-mediated suppression of CDK6 expression on the proliferation and cell cycles of nasopharyngeal carcinoma (NPC) cells in vitro. METHODS: QRT-PCR was used to examine the differential expression of CDK6 in 30 NPC tissues and 18 normal nasopharyngeal tissues. A siRNA targeting CDK6 was transfected in NPC CNE2 cells, and MTT assay and flow cytometry were used to analyze the changes in cell proliferation and cell cycle distribution. Western blotting was used to examine the expressions of the cell cycle-related factors. RESULTS: Compared with normal nasopharyngeal tissues, NPC tissues showed an increased expression of CDK6 mRNA. Knocking down CDK6 expression obviously inhibited tumor cell growth and cell cycle transition from G1 to S phase and caused reduced expressions of CDK4, CCND1, and E2F1 and enhanced expression of the tumor suppressor p21. CONCLUSION: NPC tissues overexpress CDK6. Knocking down CDK6 expression inhibits the growth and cell cycle transition of NPC cells in vitro by inhibiting the expressions of CDK4, CCND1, and E2F1 and upregulating tumor suppressor p21 expression.
Subject(s)
Cell Cycle , Cyclin-Dependent Kinase 6/genetics , Nasopharyngeal Neoplasms/pathology , RNA, Small Interfering , Carcinoma , Cell Line, Tumor , Cell Proliferation , Cyclin D1/metabolism , Cyclin-Dependent Kinase 4/metabolism , Cyclin-Dependent Kinase Inhibitor p21/metabolism , E2F1 Transcription Factor/metabolism , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Humans , Nasopharyngeal Carcinoma , RNA, Messenger , Transfection , Up-RegulationABSTRACT
OBJECTIVE: To explore the expression of CDK6 in nasopharyngeal carcinoma (NPC) and explore its clinical significance. METHODS: Immunohistochemistry was used to examine the differential expression of CDK6 protein in 101 NPC and 30 nasopharyngeal tissues, and the correlation of CDK6 expression with the clinical characteristics was analyzed in NPC cases. RESULTS: Immunohistochemistry demonstrated that CDK6 protein was a co-expressed factor in the cytoplasm and cell nuclei. CDK6 was expressed predominantly in the cytoplasm in nasopharyngeal tissues, but in NPC tissues, CDK6 was co-expressed predominantly in the cytoplasm and nuclei. Compared to the nasopharyngeal tissues, NPC tissues showed significantly up-regulated CDK6 expression (P=0.009) in positive correlation with tumor size (P=0.020) and clinical stages (P=0.0039). CONCLUSIONS: Increased CDK6 protein expression is an unfavorable factor that promotes the development and progression of NPC.
