title: Inducible HSP70 antagonizes IL-1β cytocidal effects through inhibiting NF-kB activation via destabilizing TAK1 in HeLa cells.
abstract: BACKGROUND
  Despite several reports describing the HSP70-mediated cytoprotection against IL-1, the precise mechanism for this phenomenon remains to be determined.
  
  
  RESULTS
  Here we used HeLa cells, a human epithelial carcinoma cell line, to evaluate the role of inducible HSP70 in response of IL-1β stimulation. We found that inducible HSP70 antagonized the cytotoxicity of IL-1β and improved the survival of HeLa cells. Further investigation demonstrated that increased expression level of inducible HSP70 reduced the complex of TAK1 and HSP90, and promoted the degradation of TAK1 protein via proteasome pathway. By overexpression and RNAi knockdown, we showed that inducible HSP70 modulated the NF-kB but not MAPKs signalings through influencing the stability of TAK1 protein in HeLa cells. Moreover, overexpression of HSP70 attenuated the production of iNOS upon IL-1β stimulation, validating that inducible HSP70 serves as a cytopretective factor to antagonize the cytocidal effects of IL-1β in HeLa cells.
  
  
  CONCLUSIONS
  Our observations provide evidence for a novel signaling mechanism involving HSP70, TAK1, and NF-κB in the response of IL-1β cytocidal effects. This research also provides insight into mechanisms by which HSP70 exerts its cytoprotective action upon toxic stimuli in tumor cells.
authors.affiliation: Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Cao
authors.forename: Ling
authors.initials: L
authors.lastname: Yue
authors.forename: JiYun
authors.initials: J
authors.lastname: Song
authors.forename: Qiuyue
authors.initials: Q
authors.lastname: Wu
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Lan
authors.initials: L
authors.lastname: Luo
authors.forename: Lei
authors.initials: L
authors.lastname: Lan
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Yin
mesh_terms: D005786:Gene Expression Regulation / Q000187:drug effects*; D055785:Gene Knockdown Techniques; D050884:HSP72 Heat-Shock Proteins / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006358:Hot Temperature; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000378:metabolism; D059748:Proteolysis; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D000099151:MAP Kinase Kinase Kinase 7
chemical_list: D050884:HSP72 Heat-Shock Proteins; D053583:Interleukin-1beta; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D052247:Nitric Oxide Synthase Type II; D046988:Proteasome Endopeptidase Complex; D034741:RNA, Small Interfering; D000099151:MAP Kinase Kinase Kinase 7; C496319:NOS2 protein, human