ABSTRACT
OBJECTIVE: The protein 14-3-3 sigma plays a role in cell cycle arrest by sequestering cyclin-dependent kinase 1 cyclin B1 complexes, as well as cyclin-dependent kinases 2 and 4, hence its definition as a cyclin-dependent kinase inhibitor. However, the nature of the interaction between these biological markers in nasopharyngeal carcinoma is unknown. This study aimed to investigate whether altered expression of these markers contributes to nasopharyngeal carcinogenesis. METHODS: The study population consisted of 30 nasopharyngeal carcinoma patients and 10 patients without nasopharyngeal carcinoma. The nasopharyngeal carcinoma cell lines TW02, TW04 and Hone-1 were also assessed. We analysed levels of messenger RNA and protein for the p16 gene and the 14-3-3 sigma, Epstein-Barr nuclear antigen 1, and cyclin-dependent kinase 2 and 4 proteins, in nasopharyngeal carcinoma tissue specimens and cell lines and in normal nasopharyngeal tissue. RESULTS: Protein and messenger RNA levels for cyclin-dependent kinase 2 and Epstein-Barr nuclear antigen 1 were significantly higher in nasopharyngeal carcinoma compared with normal tissue, while levels of cyclin-dependent kinase 4 generally were not; results for 14-3-3 sigma varied. Nasopharyngeal carcinoma patients had diminished p16 gene expression, compared with normal tissue. CONCLUSION: Levels of cyclin-dependent kinase 2 and Epstein-Barr nuclear antigen 1 were significantly higher in nasopharyngeal carcinoma than in normal tissue, while p16 gene expression was diminished. These three proteins may contribute to nasopharyngeal carcinogenesis.
Subject(s)
14-3-3 Proteins/analysis , Biomarkers, Tumor/analysis , Cyclin-Dependent Kinase 2/analysis , Cyclin-Dependent Kinase 4/analysis , Epstein-Barr Virus Nuclear Antigens/analysis , Exoribonucleases/analysis , Nasopharyngeal Neoplasms/chemistry , Neoplasm Proteins/analysis , Adult , Aged , Carcinoma , Case-Control Studies , Cell Line, Tumor/chemistry , Cyclin-Dependent Kinase Inhibitor p16 , Female , Humans , Male , Middle Aged , Nasopharyngeal Carcinoma , Nasopharynx/chemistry , Young AdultABSTRACT
Matrix metalloproteinase (MMP)-2 plays critical roles in tumor development and in the metastasis of multiple cancers, including human oral cavity squamous cell carcinoma (OCSCC). One of the upstream regulators of MMP-2 is FOXM1, which is overexpressed in a microarray dataset of OCSCC. It is interesting that FLJ10540 exhibits similar gene expression profiles with MMP-2 and FOXM1, raising the possibility that these molecules might participate in MMP-2-elicited cancer progression and metastasis of OCSCC. To examine this connection, we first showed that FLJ10540 was significantly overexpressed in OCSCC. A strong FLJ10540 expression was significantly correlated with an advanced tumor node metastasis stage and the cumulative 5-year survival rate. Thus, an elevated FLJ10540 expression is an indicator of poor survival. Functionally, FLJ10540 had the abilities to stimulate cell migration and invasion in oral cancer cells through increased FOXM1 and MMP-2 expressions. Conversely, the depletion of the FLJ10540 expression by small interfering RNAs suppressed the FOXM1 and MMP-2 protein expressions. The suppression of either FLJ10540 or FOXM1 could cause significant inhibition on cell migratory and invasive ability in oral cancer cells. Finally, the immunohistochemical and western blotting analyses of human aggressive OCSCC specimens showed a significant positive correlation among FLJ10540, FOXM1 and MMP-2 expressions. These findings suggest that FLJ10540 is not only an important prognostic factor but also a new therapeutic target in the FLJ10540/FOXM1/MMP-2 pathway for OCSCC treatment.
Subject(s)
Carcinoma, Squamous Cell/pathology , Cell Cycle Proteins/physiology , Forkhead Transcription Factors/physiology , Matrix Metalloproteinase 2/physiology , Mouth Neoplasms/pathology , Nuclear Proteins/physiology , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/chemistry , Carcinoma, Squamous Cell/mortality , Cell Cycle Proteins/analysis , Cell Movement , Female , Forkhead Box Protein M1 , Humans , Immunohistochemistry , Male , Matrix Metalloproteinase 14/physiology , Middle Aged , Mouth Mucosa/chemistry , Mouth Neoplasms/chemistry , Mouth Neoplasms/mortality , Neoplasm Invasiveness , Nuclear Proteins/analysis , RNA, Small Interfering/geneticsABSTRACT
AIMS: S-phase kinase-associated protein 2 is required for the degradation of p27 protein, which is a negative regulator of cyclin E/cyclin-dependent kinase 2 complex. The present study examined the expression of cyclin E, S-phase kinase-associated protein 2 and p27 protein in nasopharyngeal carcinoma. METHODS: Tissue from 35 cases of nasopharyngeal carcinoma and 10 normal nasopharyngeal tissue samples underwent reverse polymerase chain reaction to detect messenger ribonucleic acid. Immunohistochemical analysis was performed on 29 nasopharyngeal tissue samples in order to detect protein expression. RESULTS: Messenger ribonucleic acid expression in the nasopharyngeal carcinoma tissue samples analysed indicated a 1.75-fold change in the amount of S-phase kinase-associated protein 2, a 0.34-fold change in the amount of cyclin E and a 0.31-fold change in the amount of p27 protein, compared with positive controls. High levels of cyclin E significantly correlated with late-stage nasopharyngeal carcinoma (p = 0.009) and a poor overall survival (p = 0.010). Immunohistochemical analysis indicated positive expression of S-phase kinase-associated protein 2 in 16/29 nasopharyngeal tissue samples (55 per cent), of cyclin E in 13/29 samples (45 per cent) and of p27 protein in 17/29 (59 per cent) samples. CONCLUSIONS: Overexpression of cyclin E messenger ribonucleic acid showed an adverse prognostic significance, correlating with an advanced stage of nasopharyngeal carcinoma and a low overall survival rate.
Subject(s)
Cyclin E/metabolism , Cyclin-Dependent Kinase Inhibitor p27/metabolism , Nasopharyngeal Neoplasms/metabolism , Neoplasm Proteins/metabolism , RNA Transport/physiology , S-Phase Kinase-Associated Proteins/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Cyclin E/genetics , Cyclin-Dependent Kinase Inhibitor p27/genetics , Female , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , Male , Middle Aged , Nasopharyngeal Neoplasms/mortality , Nasopharyngeal Neoplasms/pathology , Neoplasm Proteins/genetics , Prognosis , Prospective Studies , RNA Transport/genetics , S-Phase Kinase-Associated Proteins/genetics , Survival Analysis , Young AdultABSTRACT
BACKGROUND: The cyclin D1/p16/Rb pathway plays a critical role in tumorigenesis and each component of this pathway may be affected in various malignancies. The purpose of this study was to investigate the expression and prognostic significance of these proteins in nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS: Sixty-five patients undergoing radiotherapy for NPC were analyzed. The expression of cyclin D1, p16 and pRb was evaluated with immunohistochemical analysis of archived pretreatment tumor materials and expression of these proteins was correlated with clinicopathological parameters. RESULTS: Positive expression of cyclin D1 was observed in 43 of 65 NPCs (66%). p16 and pRb inactivation was identified in 42 of 65 (65%) and four of 65 (6%) tumors, respectively. All but seven tumors (58 of 65, 89%) contained at least one alternation in the cyclin D1/p16/Rb pathway. Loss of cyclin D1 as well as p16 was closely related to local recurrence after radiotherapy for NPC (P = 0.015 and 0.047). No association between pRb expression and clinicopathological outcome was apparent. CONCLUSIONS: The study's results suggest that the cyclin D1/p16/Rb pathway plays an important role in NPC tumorigenesis. We also find that cyclin D1 and p16 protein levels in NPC may be of use clinically as a predictor of local tumor control.
