[Effect of As2O3 on demethylation of SHP-1 gene in human lymphoma cell line T2].
OBJECTIVE
Inducing gene demethylation may be a mechanism of arsenic trioxide (As(2)O(3)) in treating hematologic cancers. This study was to investigate the effect of As(2)O(3) on demethylation of SH2-containing phosphatase-1 (SHP-1) in human lymphoma cell line T2 and on the proliferation of T2 cells.


METHODS
T2 cells were treated with As(2)O(3) and 5-aza-2'-deoxyoytidine (5-AC) alone or in combination. The methylation of SHP-1 in T2 cells was detected by methylation-specific polymerase chain reaction (MSP). The mRNA and protein expression of SHP-1 were determined by fluorescence quantitative-polymerase chain reaction (FQ-PCR) and Western blot. The expression of p-c-kit was detected by Western blot. Cell proliferation was detected by MTT assay. Cell apoptosis was detected by flow cytometry.


RESULTS
As(2)O(3) led to progressive demethylation and re-expression of SHP-1 in T2 cells, as well as down-regulation of phosphorylated c-kit. As(2)O(3) inhibited the proliferation and promoted the apoptosis of T2 cells, and its effects were enhanced along with the increase of concentration and treatment time (p<0.05). The proliferation inhibition rates were significantly lower in As(2)O(3) (2.5 micromol/L) group than in combination (2.5 micromol/L As(2)O(3) plus 2 micromol/L 5-AC) group (9.8% vs. 11.0%on Day 1, 20.3% vs. 36.7% on Day 2, 47.5% vs. 61.0% on Day 3, p<0.05). The apoptosis rates were significantly higher in combination group than in As(2)O(3) group (17.3% vs. 6.1% on Day 1, 37.9% vs. 26.5% on Day 2, 67.9% vs. 50.9% on Day 3, p<0.05).


CONCLUSIONS
As(2)O(3) could cause demethylation and re-expression of SHP-1 in T2 cells, and may inhibit proliferation and induce apoptosis of T2 cells via suppressing activation of c-kit receptor and its signal transduction.
Yang
Lin
L
Department of Hematology, The Second Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, P. R. China.
Luo
Jian-Min
JM
Wen
Shu-Peng
SP
Liu
Xiao-Jun
XJ
Du
Xing-Yan
XY
Li
Yan
Y
D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000008:administration & dosage / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019175:DNA Methylation; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008223:Lymphoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010087:Oxides / Q000008:administration & dosage / Q000494:pharmacology*; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000235:genetics / Q000378:metabolism*; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D000970:Antineoplastic Agents; D001152:Arsenicals; D010087:Oxides; D012333:RNA, Messenger; D019009:Proto-Oncogene Proteins c-kit; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D000077237:Arsenic Trioxide