Promotion of cell proliferation by HBXIP via upregulation of human telomerase reverse transcriptase in human mesenchymal stem cells1

Authors

  • Feng-ze WANG,

    1. Department of Biochemistry, Tianjin Key Laboratory of Microbial Functional Genomics, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
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  • Li SHA,

    1. Department of Cancer Research, Tianjin Key Laboratory of Microbial Functional Genomics, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
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  • Li-hong YE,

    Corresponding author
    1. Department of Biochemistry, Tianjin Key Laboratory of Microbial Functional Genomics, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
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  • Xiao-dong ZHANG

    Corresponding author
    1. Department of Cancer Research, Tianjin Key Laboratory of Microbial Functional Genomics, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
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  • 1

    Project supported by grants from the National Basic Research Program of China (973 Program, No 2007CB914800) and the National Natural Science Foundation of China (No 30670959).

Correspondence to Prof Xiao-dong ZHANG and Prof Li-hong YE. Phn 86-22-2350-6830. Fax 86-22-2350-1385. E-mail zhangxd@nankai.edu.cn (Xiao-dong ZHANG) E-mail yelihong@nankai.edu.cn (Li-hong YE)

Abstract

Aim: We previously found that the hepatitis B X-interacting protein (HBXIP) was able to promote the proliferation of cells. Telomerase activity is known to be critical in cellular senescence and its level is modulated by the regulation of the telomerase catalytic subunit, telomerase reverse transcriptase (TERT), at both the transcriptional and post-transcriptional levels. To investigate the mechanism of promoting proliferation by HBXIP, the effect of HBXIP on human TERT (hTERT) was investigated in human mesenchymal stem cells (hMSC). Methods: BMMS-03 cells and hMSC from the bone marrow of a 4-month-old elicited fetus, were transiently transfected with the pcDNA3-hbxip plasmid encoding the HBXIP gene and pSilencer-hbxip plasmid encoding RNA interference (RNAi) targeting HBXIP mRNA, followed by the examination of the hTERT promoter reporter gene by luciferase assay, and the detection of telomerase activity by telomeric repeat amplication protocol, respectively, as well as the expression levels of hTERT, c-Myc, and Bcl-2 by Western blot analysis. Results: The overexpression of HBXIP led to a significant upregulation of hTERT promoter activity, telomerase activity, and the expression levels of hTERT, c-Myc, and Bcl-2 in BMMS-03 cells. RNAi targeting HBXIP mRNA produced the opposite results completely. Conclusion: Our data demonstrated that HBXIP significantly stimulated the transcription and expression of hTERT and increased the activity of telomerase in BMMS-03 cells, which provides a new insight into the mechanism of promoting cell proliferation by HBXIP.

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