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Role of c‐Jun N‐terminal kinase activation in apoptosis induced by removal of the growth factors
Author(s) -
Ning YueBao,
Du ZhiQiang
Publication year - 2015
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1002/cbin.10425
Subject(s) - apoptosis , annexin , microbiology and biotechnology , programmed cell death , kinase , downregulation and upregulation , bcl xl , cell culture , biology , chemistry , biochemistry , gene , genetics
Apoptosis plays a crucial role for generation of lymphocyte repertoire, clonal contraction, and elimination of virus‐infected cells. Since IL‐3‐dependent pro‐B cell line Baf‐3 resulted in rapid induction of apoptotic cell death upon IL‐3 withdrawal, it would by very valuable for analysis of apoptosis induction by growth factor deprivation. First, we confirmed that Baf‐3 cells underwent loss of mitochondrial membrane potential (ΔΨm) and apoptosis in a time‐dependent manner when they were cultured in the RPMI‐1640 medium without IL‐3. Induction of apoptosis and loss of ΔΨm was determined by DiOC6 and annexin V staining method using flow cytometer, respectively. Deprivation of IL‐3 induced upregulation of proapoptotic molecule Bax, in conjunction with slight down‐regulation of anti‐apoptotic molecule Bcl‐xL, which was assessed by Western blotting. Since Bcl‐xL‐overexpressing Baf‐3 cells showed some resistance to IL‐3‐deprivation, Bcl‐xL prevents apoptosis induced by IL‐3 withdrawal. Finally, a sustained JNK1 activation was observed prior to induction of apoptosis upon IL‐3 deprivation. Dominat‐negative form of JNK1 and JNK inhibitor sp600125 partially inhibit the apoptosis upon IL‐3 deprivation, suggesting that a sustained JNK1 activation was involved in the induction of apoptosis. Together, IL‐3 deprivation of IL‐3‐dependent cell line Baf‐3 induces a sustained JNK1 activation, followed by a decline of the ratio of Bcl‐xL to Bax, leading to loss of ΔΨm, and finally apoptosis.