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The Bcl‐2 family members Mcl‐1 and Bim modulate apoptosis in glutamine‐deprived Sp2/0‐Ag14 mouse cells
Author(s) -
Gauthier Eric R.,
Zhou Catherine,
Woodley Jenna,
Harnett Curtis
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1032.1
Subject(s) - puma , glutamine , apoptosis , programmed cell death , western blot , cell culture , reprogramming , biology , downregulation and upregulation , microbiology and biotechnology , flow cytometry , cell , chemistry , biochemistry , amino acid , genetics , gene
In highly proliferating cells, metabolic reprogramming results in a cellular dependence toward L‐glutamine (Gln), a phenomenon of marked therapeutic interest. However, the molecular events linking Gln to cell survival are still poorly defined. Our group has shown that Sp2/0‐Ag14 (Sp2/0) cells are acutely sensitive to Gln starvation, undergoing apoptosis via the intrinsic pathway after only 2 hours of Gln deprivation. The current study examined the relative contribution of proteins of the Bcl‐2 family in this phenomenon. Immunoblotting revealed that Mcl‐1, Bax, Bim and Puma are the major Bcl‐2 family proteins expressed in Sp2/0 cells. While Sp2/0 cells with an RNAi‐induced decrease in Puma levels behaved like the wild‐type cell line, reducing Bim expression led to a significant increase in cell survival following Gln deprivation. Western blot analysis revealed that Gln starvation did not affect Bim levels, but did lead to a reduction in Mcl‐1. We found that Sp2/0 cells are highly sensitive to obatoclax, a Mcl‐1‐specific chemical inhibitor. Furthermore, obatoclax increased the sensitivity of Sp2/0 cells to glutamine starvation, an effect prevented by the constitutive expression of Bcl‐xL (which is not targeted by the drug). All together, our data place Mcl‐1 and Bim at the core of the apoptotic machinery triggered by Gln starvation in Sp2/0 cells. Funded by NSERC‐CANADA (to ERG).