目的 探讨17-二甲基胺乙基-17-去甲氧基格尔德霉素(17-DMAG)对PD-1人源化小鼠人肝癌移植肿瘤生长的抑制作用.方法 选取30只PD-1人源化小鼠,将HepG2细胞悬液注射于小鼠右侧腹股沟皮下组织,构建人肝癌移植瘤模型;将荷瘤人源化小鼠随机分为3组(每组10只):①模型组(注射生理盐水10 mg/kg);②17-DMAG组(按25 mg/kg腹腔注射17-DMAG,3次/周);③顺铂组(腹腔注射20 mg/kg,2次/周),实验持续4周.注射结束后测量人源化小鼠移植瘤的长、短径计算体积,测量肿瘤质量计算抑瘤率,同时采用免疫组化方法检测肿瘤组织中CD31(以阳性细胞数计算肿瘤微血管密度(MVD))及血管内皮生长因子(VEGF)的表达.结果 17-DMAG 组和顺铂组的肿瘤体积和质量均较模型组显著减小(P＜0.05),17-DMAG组的抑瘤率略高于顺铂组,但17-DMAG组和顺铂组肿瘤质量和体积以及抑瘤率均不存在显著性差异.17-DMAG组和顺铂组MVD标记微血管数量及VEGF表达均低于模型组(P＜0.05),且17-DMAG组又低于顺铂组(P＜0.05).结论 17-DMAG可显著降低肝癌移植瘤中VEGF的表达,抑制新生血管在肿瘤中发生发展,从而对人源化小鼠肝癌移植瘤发挥抑制作用.

Heat shock protein 90 (Hsp90) is an abundant molecular chaperone with two isoforms,Hsp90α and Hsp90β.Hsp90β deficiency causes embryonic lethality,whereas Hsp90α deficiency causes few abnormities except male sterility.In this paper,we reported that Hsp90α was exclusively expressed in the retina,testis,and brain.Its deficiency caused retinitis pigmentosa (RP),a disease leading to blindness.In Hsp90α-deficient mice,the retina was deteriorated and the outer segment of photoreceptor was deformed.Immunofluorescence staining and electron microscopic analysis revealed disintegrated Golgi and aberrant intersegmental vesicle transportation in Hsp90α-deficient photoreceptors.Proteomic analysis identified microtubule-associated protein 1B (MAP1B) as an Hsp90α-associated protein in photoreceptors.Hspα deficiency increased degradation of MAP1 B by inducing its ubiquitination,causing α-tubulin deacetylation and microtubule destabilization.Furthermore,the treatment of wild-type mice with 17-DMAG,an Hsp90 inhibitor of geldanamycin derivative,induced the same retinal degeneration as Hsp90α deficiency.Taken together,the microtubule destabilization could be the underlying reason for Hsp90α deficiency-induced RP.

目的:探讨PPP2R5C对儿童急性T淋巴细胞白血病Molt-4细胞活性的影响及其相关机制.方法:通过靶向PPP2R5C基因的小干扰RNA (siRNA)技术下调Molt-4细胞中PPP2R5C的表达,同时设置空白对照组、阴性对照组及17-DMAG组,其中阴性对照组转染siRNA-NC,17-DMAG组使用终浓度为6.4 μmol/L的热休克蛋白90(HSP90)抑制剂17-DMAG处理细胞48 h,采用实时荧光定量PCR (RT-qPCR)和免疫印迹法(Western blot)检测转染效率;CCK-8法检测各组细胞增殖活性,EdU检测各组细胞增殖水平,流式细胞术检测各组细胞周期分布比例,Annexin V-FITC/PI染色检测细胞凋亡,RT-qPCR和Western blot检测各组细胞中HSP90和糖皮质激素受体(GR)的表达变化.结果:Molt-4细胞转染siRNA-PPP2R5C后,细胞中PPP2R5C mRNA与蛋白表达均明显下调,与空白对照组和si-NC组相比有显著性差异(P＜0.05);相比空白对照组和si-NC组,siRNA-PPP2R5C组和17-DMAG组细胞的增殖活性明显降低(P＜0.05),EdU阳性细胞率明显减少(P＜0.05),G1期细胞比例减少而G2期细胞比例增加(P＜0.05),细胞凋亡率也明显增加(P＜0.05);此外,siRNA-PPP2R5C组细胞中,PPP2R5C mRNA与蛋白表达较空白对照组和si-NC组明显下调(P＜0.05),17-DMAG组细胞中PPP2R5C mRNA与蛋白表达较空白对照组和si-NC组也明显下调(P＜0.05).结论:下调PPP2R5C基因表达可抑制儿童急性T淋巴细胞白血病Molt-4细胞的活性,使细胞发生G2期阻滞,并促进细胞凋亡,其机制可能与抑制Hsp90-GR信号途径相关.