APE1/Ref-1 prevents oxidative inactivation of ERK for G1-to-S progression following lead acetate exposure.
Apurinic/apyrimidinic endonuclease 1 (APE1)/redox effector factor-1 is a multifunctional enzyme involved in DNA base excision repair and protein redox regulation. Previously, we have showed that lead acetate (Pb) elicits EGFR activation to initiate the SFK/PKCα/Ras/Raf-1/MKK1/2/ERK signaling cascade functioning against genotoxicity. Here, we explore whether APE1 and reactive oxygen species (ROS) affect ERK signaling and cell cycle progression following Pb exposure. We found that Pb induced APE1 expression and ROS generation in CL3 human lung cancer cells. The Pb-elicited ROS levels and cytotoxicity were further enhanced by introducing small interfering RNA specific for APE1 (siAPE1). E3330, an inhibitor of APE1 redox activity, also augmented the ROS levels and cytotoxicity in Pb-treated cells. Intriguingly, the capability of Pb to activate ERK was abolished under siAPE1 or E3330 co-treatments; conversely, forced expression of APE1 up-regulated the ERK activation by Pb or serum in both Cys65-redox activity dependent and independent manners. Moreover, APE1 formed complex with ERK2, and its redox activity could rescue ERK oxidative inactivation. APE1 redox activity also facilitated the Cyclin D1 expression and G1-to-S progression following Pb exposure. In summary, the results indicate that APE1 is a direct redox regulator of ERK for maintaining the kinase activity to promote cell proliferation.
Molecular Carcinogenesis Laboratory, Institute of Biotechnology & Department of Life Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan.
Yi-Ting
YT
Wang
Der-Wan
DW
Tzeng
Chun-Yu
CY
Wang
Jing-Yin
JY
Hong
Jia-Ling
JL
Yang
D016475:3T3 Cells; D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003114:Colony-Forming Units Assay; D003545:Cysteine / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors*; D016193:G1 Phase / Q000187:drug effects*; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D008938:Mitosis / Q000187:drug effects*; D009942:Organometallic Compounds / Q000633:toxicity*; D010957:Plasmids / Q000235:genetics; D011422:Propionates / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D016196:S Phase / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
D016227:Benzoquinones; D009942:Organometallic Compounds; D011422:Propionates; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C075569:E 3330; D048049:Extracellular Signal-Regulated MAP Kinases; C486216:Apex1 protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D003545:Cysteine; C008261:lead acetate