Sorafenib,rapamycin, and venetoclax attenuate doxorubicin-induced senescence and promote apoptosis in HCT116 cells

Emerging evidence has shown that the therapy-induced senescent growth arrest in cancer cells is of durable nature whereby a subset of cells can reinstate proliferative capacity. Promising new drugs named senolytics selectively target senescent cells and commit them into apoptosis. Accordingly, senolytics have been proposed as adjuvant cancer treatment to cull senescent tumor cells, and thus, screening for agents that exhibit senolytic properties is highly warranted. Our study aimed to investigate three agents, sorafenib, rapamycin, and venetoclax for their senolytic potential in doxorubicin-induced senescence in HCT116 cells. HCT116 cells were treated with one of the three agents, sorafenib (5 µM), rapamycin (100 nM), or venetoclax (10 µM), in the absence or presence of doxorubicin (1 µM). Senescence was evaluated using microscopy-based and flow cytometry-based Senescence-associated-β-galactosidase staining (SA-β-gal), while apoptosis was assessed using annexin V-FITC/PI, and Muse caspase-3/-7 activity assays. We screened for potential genes through which the three drugs exerted senolytic-like action using the Human Cancer Pathway Finder PCR array. The three agents reduced doxorubicin-induced senescent cell subpopulations and significantly enhanced the apoptotic effect of doxorubicin compared with those treated only with doxorubicin. The senescence genes IGFBP5 and BMI1 and the apoptosis genes CASP7 and CASP9 emerged as candidate genes through which the three drugs exhibited senolytic-like properties. These results suggest that the attenuation of doxorubicin-induced senescence might have shifted HCT116 cells to apoptosis by exposure to the tested pharmacological agents. Our work argues for the use of senolytics to reduce senescence-mediated resistance in tumor cells and to enhance chemotherapy efficacy.     

雷帕霉素靶蛋白反义RNA真核表达载体的构建及其在血管平滑肌细胞中的表达

目的构建雷帕霉素靶蛋白（mTOR）的反义RNA真核表达载体，观察其对血管平滑肌细胞（VSMC）功能的影响。方法提取人VSMC总RNA，逆转录．聚合酶链反应（RT-PCR）扩增mTOR基因cDNA序列，经pGEM-T载体克隆后双酶切，将cDNA序列反向插入绿色荧光蛋白表达载体pEGP-C1，转染VSMC，Westernblot法检测反义表达载体对mTOR蛋白表达的影响，流式细胞仪检测细胞周期的变化。结果经RT-PCR获得664bp产物，T载体克隆后，酶切确定该片段为mTOR基因cDNA，进而构建反义RNA真核表达载体pEGFP-C1-mTOR，测序证明序列正确后转染VSMC，证实其能够显著抑制mTOR蛋白产物表达，转染72h的mTOR蛋白产物表达抑制率达82％，S期细胞由15％降低为7％，凋亡细胞增至9％。VSMC增殖过程在Gx／Go期→S期受阻。结论成功构建mTOR基因的反义RNA真核表达载体。     

Iron deficiency down-regulates the Akt/TSC1-TSC2/mammalian Target of Rapamycin signaling pathway in rats and in COS-1 cells

Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity.     

雷帕霉素对人肝癌裸鼠原位移植瘤生长的抑制作用

目的探讨雷帕霉素对人肝癌裸鼠原位移植瘤生长的影响及其机制。方法建立人肝癌棵鼠肝原位移植瘤模型32只,随机分为空白对照组、FK506组、雷帕霉素常规剂量组和高剂量组。用药两周后观察肿瘤体积的变化,免疫组织化学法检测肝癌组织中增殖细胞核抗原(PCNA)、血管内皮细胞生长因子(VEGF)的表达。结果对照组、FK506组、雷帕霉素常规剂量组、高剂量组平均肿瘤体积分别为:(310．15±40．16)、(605．59±116．23)、(99．19±15．27)、(151．61±27．81) mm3。与对照组相比,雷帕常规剂量组及高剂量组肿瘤体积明显缩小,PCNA、VEGF的表达均显著下调(P<0．01);FKS06组肿瘤体积与对照组相比明显增大,差异有统计学意义(P<0．01),PC- NA、VEGF的表达与对照组相比差异无统计学意义(P>0．01)。结论雷帕霉素具有显著抑制肝癌生长的作用,其机制可能是抑制了肝癌细胞的恶性增殖及VEGF的产生。     

药物洗脱支架直接置入治疗A型和B_1型病变的临床观察

目的　评价直接置入药物洗脱支架 (CYPHERTM,codis)在A或B1 型病变的冠心病患者治疗中的安全性、可行性。方法　 6 2例接受CYPHERTM 支架直接置入的患者 (直接支架组 )和一般情况匹配的 5 1例球囊扩张后行冠脉支架术的患者 (常规支架组 ) ,比较两组的一般情况 ,冠脉造影及介入治疗即刻和临床随访结果。结果　直接支架组介入操作时间明显短于常规支架组 [(17.2± 8.6 )比 (2 6 .3± 7.1)min ,P <0 .0 1],直接支架组平均扩张压明显高于常规支架组 [(14± 3)比 (12± 1.9)atm ,P<0 .0 1],两组无一例发生介入治疗相关的严重心脏事件。随访期间两组严重心脏不良事件发生率无显著差异。结论　A或B1 型病变的冠心病患者CYPHERTM 支架直接置入术可缩短介入操作时间 ,即刻效果、并发症及中期临床随访与常规支架组差异无显著性意义     

雷帕霉素对炎性反应状态下肾小球系膜细胞内脂质稳态的影响

Objective To investigate the effect of rapamycin on cholesterol homeostasis of glomerular mesangial cells and the underlying mechanism. Methods Glomerular mesangial cell line (HMCL) cells were cultured and divided into control group, IL-1β group and different concentration rapamycin groups. Intracellular cholesterol accumulation was observed and measured by oil O staining and HPLC. Real-time quantitative PCR and Western blot were used to detect the mRNA and protein expression of LDLR, PPARγ, LXRα, ABCA1 in HMCL after the treatment with IL-1β and rapamycin. Results Rapamycin had no significant influence on intracellular cholesterol concentration under normal condition. IL-1β significantly increased the intracellular cholesterol concentration by 143％ of control (P<0.05), and 10, 50, 100 ?滋g/L rapamycin could significantly inhibit the effect of IL-1β (87％, 116％, 96％ of control respectively, all P<0.05). Rapamycin could suppress the increased expression of LDLR caused by IL-1β on both mRNA and protein level in a dose-dependent manner（P<0.01）. Rapamycin dose-dependently up-regulated the reduced mRNA and protein expression of ABCA1, the decreased mRNA expression of PPARγ and LXRα induced by IL-1β as well (P<0.01）. Conclusion Rapamycin may contribute to the maintenance of intracellular cholesterol homeostasis in glomerular mesangial cells under inflammatory state by both reducing cholesterol uptake and promoting cholesterol efflux.     

免疫抑制剂SIIA9268A的研究.Ⅰ.发酵、分离及理化性质

在用含ｒａｐａｍｙｃｉｎ结合蛋白基因（ＲＢＰ）的啤酒酵母ＲＳ１８８Ｎ及其变株ＲＳ１８８Ｎ△ｒｂｐ：：：ＬＥＵ筛选免疫抑制剂的过程中，得到活性菌株Ｎｏ．ＳＩＩＡ９２６８（鉴定为吸水链霉菌东湖变种）。应用硅胶柱层析和制备ＴＬＣ等方法从其发酵液中分离出活性化合物ＳＩＡ９２６８Ａ。经理化性质鉴定与ｒａｐａｍｙｃｉｎ同质。     

Activation of MAP kinases,pp90rsk and pp70-S6 kinases in mouse mast cells by signaling through the c-kit receptor tyrosine kinase or FcϵRI: rapamycin inhibits activation of pp70-S6 kinase and proliferation in mouse mast cells

The high-affinity receptor for IgE, Fc_?RI, represents the major cell surface structure through which mast cells express immunologically specific secretory function. By contrast, the stem cell factor receptor (SCFR), which is encoded by c-kit, is essential for normal mast cell development. The signaling pathways initiated by the stimulation of mast cells through the Fc_?RI, which lacks intrinsic kinase activity, and the SCFR, a member of the receptor tyrosine kinase family, generally have been regarded to be distinct. We report here that mouse mast cells stimulated either with SCF or with IgE and specific antigen exhibit a remarkably similar pattern of activation of mitogen-activated protein kinases (MAPK), 90 kDa-S6 kinases (pp90^rsk), and pp70-S6 kinases (pp70-S6K). These results indicate that all three families of protein kinases are associated with the cell surface receptor-dependent activation of secretion, as well as proliferation, in mast cells. We also show that the immunosuppressant rapamycin, but not FK506, can inhibit both SCF-dependent pp70-S6 kinase activation and SCF-dependent proliferation in mouse mast cells, without suppressing IgE- and antigen-dependent mediator release. These findings suggest that the activation of pp70-S6 kinase represents an important link in the stimulation of cell proliferation by SCF. Our results also indicate that the intracellular signaling pathways initiated by stimulation of mast cells through the Fc_?RI or the SCFR exhibit more overlap than has previously been appreciated.     

雷帕霉素抑制LPS诱导的RAW264.7细胞表达和释放HMGB1的机制

目的：探讨雷帕霉素抑制LPS诱导小鼠RAW264.7细胞表达和释放HMGB1的作用机制。方法:传代培养的小鼠RAW264.7细胞分5组接种于6孔板，即仅加培养液的对照组；加250 μg/L LPS的诱导组； 诱导组基础上加100 μg/L雷帕霉素的干预组；干预组基础上加rTNF-α 50 μg/L的抗干预组；及抗干预组基础上加抗鼠TNF-α 100 μg/L的抗体中和组。培养4 h后，ELISA法检测对照组、诱导组和干预组上清液中TNF-α水平；培养24 h后，RT-PCR和Western blotting法分别检测各组细胞内HMGB1 mRNA表达水平和上清液中HMGB1含量。结果:培养4 h，干预组上清液中TNF-α水平与对照组比无显著差异（P>0.05），但明显低于诱导组（P<0.05）；培养24 h, 与对照组比，诱导组细胞内HMGB1 mRNA表达明显增强（P<0.05），上清液中HMGB1含量也明显增多（P<0.05）；干预组明显减少了HMGB1 mRNA表达及上清液中HMGB1含量（P<0.05）； 与干预组比，抗干预组细胞HMGB1 mRNA表达及上清液中HMGB1含量明显增加（P<0.05）；抗体中和组细胞HMGB1 mRNA表达水平及上清液中HMGB1含量和干预组无显著差异（P>0.05）。 结论:雷帕霉素抑制LPS诱导RAW264.7细胞表达和释放HMGB1，可能部分地与其抑制TNF-α的表达有关。     

雷帕霉素抑制兔眼后发性白内障的实验研究

目的：探讨雷帕霉素（Rapamycin,RAPA）抑制兔眼后发性白内障发生的有效性及可行性。方法：雄性新西兰大白兔12只，24眼随机分为空白对照组，RAPA 7.5、15和30?ng/ml组,4组均行超声乳化透明晶状体吸除术；实验组灌注液中分别加入不同浓度的RAPA。术后不同时间裂隙灯观察兔眼角膜、房水及晶状体后囊膜混浊情况；3个月后处死动物，分别对4组兔眼行组织病理学及电镜检查。结果：术后12周，RAPA15?ng/ml组和30?ng/ml组后囊混浊发生率较对照组明显减少（P＜0.05）；各组术后裂隙灯下角膜混浊度无明显差异。结论：浓度为15～30?ng/ml的RAPA灌注液可有效抑制兔眼后发性白内障的发生且对角膜无明显的毒性作用。