Abstract | PURPOSE: METHODS: After a down-regulation of HMGB1 expression by lentivirus-mediated RNAi, the effect of knocking down HMGB1 on hypoxia-induced mitochondrial biogenesis was examined. NRF-1/TFAM expression, mtDNA copy number, ATP content and mitochondrial number/morphology in hypoxia-treated pancreatic cancer cells were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot, mtDNA and ATP assay kits and electron microscopy, respectively. Cell proliferation was measured by MTS assay. And protein and acetylation levels of PGC-1α and SIRT1 activity were detected by Western blot, immunoprecipitation (IP) and SIRT1 activity kit. RESULTS:
Hypoxia enhanced the expressions of NRF-1/TFAM, boosted mtDNA copy number and ATP content and increased the number of mitochondria in pancreatic cancer cells while induction was suppressed by a knockdown of HMGB1. Knocking down HMGB1 expression lowered hypoxia-induced PGC-1α/ SIRT1 expression and activity, phosphorylation of AMPK. PGC-1α over-expression by a plasmid transfection failed to boost mtDNA copy number or ATP content in HMGB1-knockdown cells. A knockdown of HMGB1 attenuated hypoxia with AICAR (an AMPK activator)-induced expression of NRF-1, TFAM, PGC-1α, SIRT1 and the proteins of complexes Ⅰ& Ⅲ and reduced the acetylation level of PGC-1α/ SIRT1 activity. Additionally, SRT1720 (a SIRT1 activator)-induced elevation in SIRT1 activity boosted hypoxia-induced PGC-1α deacetylation, except in HMGB1-knockdown cells. CONCLUSION: As a novel regulator of mitochondrial biogenesis via AMPK/ SIRT1 pathway under hypoxia, HMGB1 may become a potential drug target for therapeutic interventions in pancreatic cancer.
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Authors | Liangchun Yang, Fanghua Ye, Li Zeng, Yanling Li, Wenwen Chai |
Journal | OncoTargets and therapy
(Onco Targets Ther)
Vol. 13
Pg. 1187-1198
( 2020)
ISSN: 1178-6930 [Print] New Zealand |
PMID | 32103987
(Publication Type: Journal Article)
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Copyright | © 2020 Yang et al. |