Enhanced expression of halp gene confers cellular resistance to H2O2 induced senescence.
OBJECTIVE
To investigate the H2O2-induced expression of human histone acetyltransferase-like protein (hALP), a telomerase regulation-associated gene, and its effects on the stress-triggered cellular senescence.


METHODS
The induced expression of hALP was measured by semi-quantitative RT-PCR and immunofluorescent histochemistry after treatment of HeLa cells by H2O2. The effects of hALP expression on cellular responses to H2O2 were analyzed by MTT, flowcytometry, and SA-beta-gal staining, respectively.


RESULTS
hALP mRNA could be dose-dependently induced by treatments of 0.2-1.6 mmol/L H2O2, and the induction could be observed after 6 hours and kept for 36 hours in the presence of 0.4 mmol/L H2O2. Meanwhile, the immunofluorescent staining showed marked stronger nuclear intensity of hALP protein in H2O2-treated HeLa cells. In the treatment of H2O2, the ectopic expression of hALP enhanced continuous growth and overcame G2/M arrest as well as decreased senescence-associated beta-gal staining. On the contrary, the transfected clones with antisense or blank vector and original He-La cells presented growth suppression, G2/M delay and higher percentage of SA-beta-gal activities in the presence of H2O2.


CONCLUSIONS
The expression of hALP could be up-regulated by treatment of H2O2, and elevated expression could enhance cellular resistance to H2O2-induced cellular senescence. The data might be of references to elucidation of basic biological function of hALP gene and its associated telomerase activity.
Ling
Yun
Y
Department of Pathology, Qiqihar Medical College, Qiqihar 161042.
Liu
Hai-jing
HJ
Hou
Lin
L
Zhang
Bo
B
D001215:Asparaginase / Q000096:biosynthesis* / Q000235:genetics; D001324:Autoantigens / Q000096:biosynthesis* / Q000235:genetics; D002453:Cell Cycle; D049109:Cell Proliferation; D016922:Cellular Senescence / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000494:pharmacology*; D016877:Oxidants / Q000008:administration & dosage / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D014162:Transfection; D015854:Up-Regulation
D001324:Autoantigens; D016877:Oxidants; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; C466840:ASRGL1 protein, human; D001215:Asparaginase