组蛋白去乙酰化酶抑制剂曲古菌素A联合全反式维甲酸诱导PLZF-RARα阳性U937细胞分化

Differentiation of PLZF-RARα-positive U937 leukemic cells induced by histone deacetylase inhibitor trichostatin A in combination with all-trans retinoic acid

目的:研究组蛋白去乙酰化酶抑制剂曲古菌素A(TSA)和全反式维甲酸(ATRA)对PLZF-RARα阳性细胞的作用.方法:稳定转染PLZF-RARα基因的U937细胞(U937/PLZF)经TSA,ATRA作用一段时间后,Wright-Giemsa染色观察细胞形态,MTT法检测细胞生长和增殖状态,流式细胞仪检测细胞周期和细胞表面分化抗原CD11b,CD64,CD14等的表达,荧光免疫细胞化学染色检测融合蛋白表达,细胞化学染色和硝基蓝四氮唑(NBT)还原试验观察细胞功能分化情况.结果:U937/PLZF细胞在去除四环素条件培养后,PLZF-RARα表达明显增加.TSA(30μg/L)联合ATRA(1μmol/L)使U937/PLZF细胞核质比缩小,生长增殖受抑,S期细胞减少,CD11b表达增高,PLZF-RARα蛋白表达减弱,分布以胞核弥漫细小颗粒为主,细胞功能上的分化可能尚不成熟.结论:组蛋白去乙酰化酶抑制剂TSA联合ATRA可使U937/PLZF细胞发生部分分化.

AIM： To investigate effects of all-trans retinoic acid （ATRA） and trichostatin A （TSA）, a histone deacetylase inhibi- tor, on PLZF-RARot-positive cells. METHODS： PLZF-RARot- positive U937 cells （U937/PLZF） were used as an in vitro model. The change of cell morphology was observed by Wright- Giemsa staining, cell, growth and proliferation were detected by methyl thiazolyl tetrazolium （MTT） assay, cell cycle distribution and expression of cell membrane surface differentiation-related antigens （such as CDllb, CD64 and CD14） were determined by flow cytometry assay. Expression of PLZF was analyzed by immunofluorescence. Functional differentiation was reflected by nitroblue tetrazolium （NBT） reduction ability and cytochemical staining. RESULTS： While U937/PLZF ceils were incubated in tetracycline-withdrawn medium, the expression of PLZF-RARot protein was increased. After treated with TSA （30 μg/L） and RA （1 μnol/L）, U937/PLZF cells presented morphologically some features of differentiated cells. The cell growth and proliferation were inhibited in a dose- and time-dependent manner. The num- ber of cells in S phage was decreased and the level of CDllb was increased. The expression of PLZF relocated in treated cells. However, no significant difference in NBT assay and cytochemical staining was documented with the combination therapy. CONCLUSION ： The combination of histone deacetylase inhibitor TSA with ATRA can cause partial differentiation of PLZF-RARot positive U937 cells.