Overexpression of hTERT extends replicative capacity of human nucleus pulposus cells, and protects against serum starvation-induced apoptosis and cell cycle arrest
JOURNAL OF CELLULAR BIOCHEMISTRY
Authors: Liang, Weiguo; Ye, Dongping; Dai, Libing; Shen, Yan; Xu, Jiake
Abstract
The nucleus pulposus (NP) cells are chondrocyte-like cells that are required for the resistance of compressive loads through the synthesis of collagen fibrils and proteoglycan aggrecans, and the generation of a hydrostatic swelling pressure, and thus play an important role in the intervertebral disc. Here, we report the production and characterization of an immortalized human NP cell line from normal NP cells using stable transfection of recombinant human telomerase reverse transcriptase (hTERT) gene. The hTERT-transfected NP cells exhibited morphological characteristics typical of native cells. When compared with the first generation of normal NP cells, the hTERT-transfected NP cells grew faster and had an increased level of IGF-1 and TGF-beta gene expression. They were successfully passaged over 20 generations without significant change in the levels of type II collagen and proteoglycan aggrecan expression. In addition, they showed resistance to serum starvation-induced apoptosis, G1 cell cycle arrest, and gene expression of p53, CCNE1, Fas, and Caspase 3. Moreover, histology revealed that no tumorigenicity of NP cells over expressing hTERT was observed after they were implanted in nude mice. Taken together, an immortalized human NP cell line was established, which has an extended lifespan, retains phenotypic features similar to primary parent NP cells, and should provide a suitable model for studying the biology of NP cells. J. Cell. Biochem. 113: 21122121, 2012. (C) 2012 Wiley Periodicals, Inc.
Combined CCNE1 high-level amplification and overexpression is associated with unfavourable outcome in tubo-ovarian high-grade serous carcinoma
JOURNAL OF PATHOLOGY CLINICAL RESEARCH
Authors: Chan, Angela M. Y.; Enwere, Emeka; McIntyre, John B.; Wilson, Holly; Nwaroh, Chidera; Wiebe, Nicholas; Ou, Young; Liu, Shuhong; Wiedemeyer, Katharina; Rambau, Peter F.; Grevers, Xin; Morris, Donald G.; Neri, Paola; Gilks, C. Blake; Visser, Frank; Le, Nhu; Luo, Li; Cook, Linda S.; Kobel, Martin
Abstract
CCNE1 amplification is a recurrent alteration associated with unfavourable outcome in tubo-ovarian high-grade serous carcinoma (HGSC). We aimed to investigate whether immunohistochemistry (IHC) can be used to identify CCNE1 amplification status and to validate whether CCNE1 high-level amplification and overexpression are prognostic in HGSC. A testing set of 528 HGSC samples stained with two optimised IHC assays (clones EP126 and HE12) was subjected to digital image analysis and visual scoring. DNA and RNA chromogenic in situ hybridisation for CCNE1 were performed. IHC cut-off was determined by receiver operating characteristics (ROC). Survival analyses (endpoint ovarian cancer specific survival) were performed and validated in an independent validation set of 764 HGSC. Finally, combined amplification/expression status was evaluated in cases with complete data (n = 1114). CCNE1 high-level amplification was present in 11.2% of patients in the testing set and 10.2% in the combined cohort. The optimal cut-off for IHC to predict CCNE1 high-level amplification was 60% positive tumour cells with at least 5% strong staining cells (sensitivity 81.6%, specificity 77.4%). CCNE1 high-level amplification and overexpression were associated with survival in the testing and validation set. Combined CCNE1 high-level amplification and overexpression was present in 8.3% of patients, mutually exclusive to germline BRCA1/2 mutation and significantly associated with a higher risk of death in multivariate analysis adjusted for age, stage and cohort (hazard ratio = 1.78, 95 CI% 1.38-2.26, p < 0.0001). CCNE1 high-level amplification combined with overexpression identifies patients with a sufficiently poor prognosis that treatment alternatives are urgently needed. Given that this combination is mutually exclusive to BRCA1/2 germline mutations, a predictive marker for PARP inhibition, CCNE1 high-level amplification combined with overexpression may serve as a negative predictive test for sensitivity to PARP inhibitors.