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TGF- β1-mediated apoptosis associated with SMAD-dependent mitochondrial Bcl-2 expression

Masoomeh Bakhshayesh1, Farhad Zaker, Mehrdad Hashemi

  • 1Cellular and Molecular Research Centre, Tehran University of Medical Sciences, Tehran, Iran. bakhflora@yahoo.com

Clinical Lymphoma, Myeloma & Leukemia
|February 3, 2012
PubMed
Abstract

Insights

Transforming growth factor-beta 1 (TGF-β1) induces apoptosis in B-lymphoma cells by altering gene expression. This study investigated the roles of SMADs, Bax, Bcl-xl, and Bcl-2 in TGF-β1-mediated apoptosis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Immunology

Background:

  • Transforming growth factor-beta 1 (TGF-β1) is a cytokine with diverse cellular functions, including the regulation of cell growth, migration, differentiation, and apoptosis.
  • TGF-β1 has been shown to induce apoptosis in specific types of lymphomas.

Purpose of the Study:

  • To investigate the molecular mechanisms by which TGF-β1 induces apoptosis in B-lymphoma cell lines.
  • To characterize the roles of SMADs, Bax, Bcl-xl, and Bcl-2 in TGF-β1-mediated apoptosis.

Main Methods:

  • Utilized two B-lymphoma cell lines: Burkitt and pre-B cell lines (Raji and Nalm 6).
  • Assessed apoptosis using flow cytometry with annexin V staining.
  • Analyzed gene and protein expression changes via reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis.

Main Results:

  • TGF-β1 treatment led to observable apoptosis in Raji and Nalm 6 cells within 24-48 hours.
  • TGF-β1 downregulated the expression of anti-apoptotic proteins Bcl-xl and Bcl-2.
  • TGF-β1 upregulated the expression of pro-apoptotic protein Bax and SMAD6/SMAD7 mRNA.

Conclusions:

  • Alterations in gene and protein expression levels are key determinants in the induction of the apoptosis pathway by TGF-β1 in lymphoma cell lines.
  • The findings provide insights into the molecular basis of TGF-β1-induced apoptosis in B-cell lymphomas.

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