Down-regulation of glutaminase C in human hepatocarcinoma cell by diphenylarsinic acid, a degradation product of chemical warfare agents.
In a poisonous incident in Kamisu, Japan, it is understood that diphenylarsinic acid (DPAA) was a critical contaminant of ground water. Most patients showed dysfunction of the central nervous system. To understand the overall mechanism of DPAA toxicity and to gain some insight into the application of a remedy specific for intoxication, the molecular target must be clarified. As an approach, a high throughput analysis of cell proteins in cultured human hepatocarcinoma HpG2 exposed to DPAA was performed by two-dimensional electrophoresis (2-DE). Four proteins, which were up- and down-regulated by exposure of cultured HepG2 cells to DPAA, were identified. They were chaperonin containing TCP-1 (CCT) beta subunit, aldehyde dehydrogenase 1 (ALDH1), ribosomal protein P0 and glutaminase C (GAC). Of these, GAC was the only protein that was down-regulated by DPAA exposure, and cellular expression levels were reduced by DPAA in a concentration- and time-dependent manner. Decrease in cellular GAC levels was accompanied by decreased activity of the enzyme, phosphate-activated glutaminase (PAG). Decreased expression of GAC by DPAA was also observed in human cervical carcinoma HeLa and neuroblastoma SH-SY5Y cells. By contrast, no significant changes in GAC protein expression were observed when cells were incubated with arsenite [iAs (III)] and trivalent dimethylarsinous acid [DMA (III)]. In the central nervous system, GAC plays a role in the production of the neurotransmitter glutamic acid. Selective inhibition of GAC expression by DPAA may be a cause of dysfunction of glutamatergic neuronal transmission and the resultant neurological impairments.
Kita
Kayoko
K
Laboratory of Toxicology, Faculty of Pharmaceutical Sciences, Teikyo University, 1091-1 Sagamiko-chou, Sagamihara, Kanagawa 229-0195, Japan. kkayoko@pharm.teikyo-u.ac.jp
Suzuki
Toshihide
T
Ochi
Takafumi
T
D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D000080924:Aldehyde Dehydrogenase 1 Family; D001152:Arsenicals / Q000378:metabolism / Q000494:pharmacology*; D018053:Arsenites / Q000494:pharmacology; D002101:Cacodylic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins / Q000494:pharmacology; D002619:Chemical Warfare Agents / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects*; D015180:Electrophoresis, Gel, Two-Dimensional; D005455:Fluorescent Antibody Technique; D005972:Glutaminase / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism; D050697:Retinal Dehydrogenase; D012269:Ribosomal Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors
D001152:Arsenicals; D018053:Arsenites; C533298:CCT2 protein, human; D002619:Chemical Warfare Agents; D007527:Isoenzymes; D012269:Ribosomal Proteins; C472511:dimethylarsinous acid; C054675:ribosomal protein P0; D002101:Cacodylic Acid; D000080924:Aldehyde Dehydrogenase 1 Family; D000444:Aldehyde Dehydrogenase; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase; D005972:Glutaminase; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins; C493087:diphenylarsinic acid