Akt Cys-310-targeted inhibition by hydroxylated benzene derivatives is tightly linked to their immunosuppressive effects.
The hydroxylated benzene metabolite hydroquinone (HQ) is mainly generated from benzene, an important industrial chemical, and is also a common dietary component. Although numerous reports have addressed the tumorigenesis-inducing effects of HQ, few papers have explored its molecular regulatory mechanism in immunological responses. In this study we characterized Akt (protein kinase B)-targeted regulation by HQ and its derivatives, in suppressing inflammatory responses using cellular, molecular, biochemical, and immunopharmacological approaches. HQ down-regulated inflammatory responses such as NO production, surface levels of pattern recognition receptors, and cytokine gene expression with IC(50) values that ranged from 5 to 10 microm. HQ inhibition was mediated by blocking NF-kappaB activation via suppression of its translocation pathway, which is composed of Akt, I kappaB alpha kinase beta, and I kappaB alpha. Of the targets in this pathway, HQ directly targeted and bound to the sulfhydryl group of Cys-310 of Akt and sequentially interrupted the phosphorylation of both Thr-308 and Ser-473 by mediation of beta-mercaptoethanol, according to the liquid chromatography/mass spectroscopy analysis of the interaction of HQ with an Akt-derived peptide. Therefore, our data suggest that Akt and its target site Cys-310 can be considered as a prime molecular target of HQ-mediated immunosuppression and for novel anti-Akt-targeted immunosuppressive drugs.
Lee
Ji Yeon
JY
School of Bioscience and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701.
Lee
Yong Gyu
YG
School of Bioscience and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701.
Lee
Jaehwi
J
College of Pharmacy, Chung-Ang University, Seoul 156-756.
Yang
Keum-Jin
KJ
Department of Pharmacology, Daejeon Regional Cancer Center, Cancer Research Institute, College of Medicine, Chungnam National University, Daejeon 310-010.
Kim
Ae Ra
AR
School of Bioscience and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701.
Kim
Joo Young
JY
School of Bioscience and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701.
Won
Moo-Ho
MH
Department of Anatomy and Neurobiology and Institute of Neurodegeneration and Neuroregeneration, College of Medicine, Hallym University, Chucheon 200-702.
Park
Jongsun
J
Department of Pharmacology, Daejeon Regional Cancer Center, Cancer Research Institute, College of Medicine, Chungnam National University, Daejeon 310-010.
Yoo
Byong Chul
BC
Research Institute and Hospital, National Cancer Center, Goyang 410-769.
Kim
Sanghee
S
College of Pharmacy, Seoul National University, Seoul 151-741.
Cho
Won-Jea
WJ
College of Pharmacy, Chonnam National University, Kwangju 500-757, Korea.
Cho
Jae Youl
JY
School of Bioscience and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701. Electronic address: jaecho@kangwon.ac.kr.
D000818:Animals; D001554:Benzene / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods; D003545:Cysteine / Q000737:chemistry; D006873:Hydroquinones / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000737:chemistry / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008623:Mercaptoethanol / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*
D006873:Hydroquinones; D007166:Immunosuppressive Agents; D008623:Mercaptoethanol; D051057:Proto-Oncogene Proteins c-akt; D001554:Benzene; D003545:Cysteine; C031927:hydroquinone