Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs. Two-condition experiment, KP MSCs vs. 3A6 MSCs.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs. One-condition experment, gene expression of 3A6
Project description:The complexity and heterogeneity of cancer cells are under-represented by the current experimental models which revolve around primary tumor cells, cancer cell lines, and rodent models. We used the transformed cell model in our studies. IMR90 and BJ fibroblast cells were transformed by three oncogenic genetic factors, SV40 Large-T antigen, H-Ras and human telomerase (hTERT). These transformed cells can grow under anchorage independent conditions, are self-sufficient in growth signals, have decreased sensitivity to apoptosis, and showed recurrent chromosomal abnormalities. Further characterization of transformed cells through cell cycle profiling and mass spectrometry analysis also revealed an increased fraction in the G2/M phase, and an up-regulation of Ku70. Furthermore, transformed cells exhibited increased telomerase activity that was not accountable by hTERT overexpression alone. Microarray results revealed that hTERT overexpression promoted cell migration and the initiation of DNA damage responses; two cellular processes that are important in cancer progression. Collectively, these data imply that IMR90 transformed cell model is an invaluable tool for cancer studies. Our results in the systematic study of this model helped us identify possible early events in cancer transformation and reveal the extra-telomeric effects of telomerase in cell migration and DNA damage initiation. IMR90 and BJ fibroblast cells were transformed by three oncogenic genetic factors, SV40 Large-T antigen, H-Ras and human telomerase (hTERT). Through microarray analysis, gene expression of transformed cells were compared against control cells.
Project description:The complexity and heterogeneity of cancer cells are under-represented by the current experimental models which revolve around primary tumor cells, cancer cell lines, and rodent models. We used the transformed cell model in our studies. IMR90 and BJ fibroblast cells were transformed by three oncogenic genetic factors, SV40 Large-T antigen, H-Ras and human telomerase (hTERT). These transformed cells can grow under anchorage independent conditions, are self-sufficient in growth signals, have decreased sensitivity to apoptosis, and showed recurrent chromosomal abnormalities. Further characterization of transformed cells through cell cycle profiling and mass spectrometry analysis also revealed an increased fraction in the G2/M phase, and an up-regulation of Ku70. Furthermore, transformed cells exhibited increased telomerase activity that was not accountable by hTERT overexpression alone. Microarray results revealed that hTERT overexpression promoted cell migration and the initiation of DNA damage responses; two cellular processes that are important in cancer progression. Collectively, these data imply that IMR90 transformed cell model is an invaluable tool for cancer studies. Our results in the systematic study of this model helped us identify possible early events in cancer transformation and reveal the extra-telomeric effects of telomerase in cell migration and DNA damage initiation.
Project description:Telomere elongation by telomerase is critical for the proliferation of human stem cells and >85-90% of cancer cells. The repression of telomerase activity during cellular differentiation promotes replicative aging and function as a physiological barrier for tumorigenesis in long-lived mammals, including humans. However, the underlying mechanisms remain unclear. We found that HoxC5 repressed hTERT, via a previously uncharacterized upstream enhancer element. HoxC5 interacts with co-repressors Pbx4 and Meis3, and recruits Class I histone deacetylases, to mediate repression of hTERT. The upstream enhancer element are conserved in long-lived primates, and HOXC5 are activated upon differentiation, consistent with diminished telomerase activity. Thus, HoxC5/Pbx4/Meis3 together constitute a developmental-controlled regulatory loop that coordinates transcriptional repression of hTERT.
Project description:Telomere length control is critical for cellular lifespan and tumor suppression. Telomerase is activated in the inner cell mass of the developing blastocyst to reset telomere reserves and its subsequent silencing in differentiated cells leads to gradual telomere shortening. Here, we report that transcriptional control through cis-regulatory elements minimally impact telomerase regulation as a function of pluripotency. Instead, developmental control of telomerase is largely driven by an alternative splicing event, centered around hTERT exon-2. Skipping of exon-2 triggers hTERT mRNA decay in differentiated cells. Conversely, its retention in pluripotent cells promotes telomerase accumulation. Our study also identifies SON as a regulator of exon-2 alternative splicing and we report a patient with insufficient telomerase and short telomeres and harboring a SON mutation. In summary, our study highlights a critical role for hTERT alternative splicing in the developmental regulation of telomerase and implicates defective splicing in telomere biology disorders.
Project description:To investigate the mechanism of telomerase regulation in BCR-ABL positive cells due to its clinical value, we studied the catalytic component of telomerase, TERT. Our results suggest that BCR-ABL plays an important role in regulating hTERT in K562 (BCR-ABL positive human leukemia) cells. When Gleevec inhibited the tyrosine kinase activity of BCR-ABL, phosphorylation of hTERT was downregulated, therefore suggesting a positive correlation between BCR-ABL and hTERT. Gleevec treatment inhibited hTERT at the mRNA level and significantly reduced telomerase activity (TA) in K562 cells, but not in HL60 or Jurkat cells. TRAP assay also revealed that Gleevec treatment significantly reduced TA specifically in K562 cells. Furthermore, translocation of hTERT from nucleoli to nucleoplasm was observed in K562 cells induced by Gleevec. Although Gleevec down-regulated hTERT mRNA level, the protein level of hTERT remained unchanged. Therefore, Gleevec-induced-TA decrease is not due to the alteration in telomerase subunits expression. It could be presumably due to posttranslational modification of hTERT, possibly through multiple signaling pathways. We have found that Gleevec reduced the tyrosine phosphorylation of hTERT by BCR-ABL, which is associated with the nucleoplasm localization of hTERT from nucleoli sequesters. These findings reveal unknown functions and regulations of telomerase by BCR-ABL.