目的:探讨磷脂酰肌醇3激酶抑制剂LY294002对人胚胎干细胞定向分化为成熟胰岛素分泌细胞的影响。方法:体外通过5个阶段诱导人胚胎干细胞定向分化为胰岛素分泌细胞。分别给予尼克酰胺+B27(B27组)为对照组和尼克酰胺+LY294002(LY组)为实验...目的:探讨磷脂酰肌醇3激酶抑制剂LY294002对人胚胎干细胞定向分化为成熟胰岛素分泌细胞的影响。方法:体外通过5个阶段诱导人胚胎干细胞定向分化为胰岛素分泌细胞。分别给予尼克酰胺+B27(B27组)为对照组和尼克酰胺+LY294002(LY组)为实验组诱导胰岛素分泌细胞的成熟。显微镜下观察各阶段细胞形态变化,免疫荧光染色鉴定胰岛素、c-肽、生长抑素和胰高血糖素的表达。结果:第5阶段诱导14 d LY组胰岛素单染阳性率与B27组无统计学差别(P﹥0.05),但生长抑素和胰高血糖素单染阳性率,胰岛素/生长抑素共染率均低于B27组(P﹤0.05)。结论:在无血清培养体系下,磷脂酰肌醇3激酶抑制剂LY294002能够诱导人胚胎干细胞分化为更加成熟的胰岛素分泌细胞。展开更多
Deregulation of the phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt)- mammalian target of rapamycin(m TOR) signaling pathway is one of the most commonlyinvolved pathways in tumorigenesis. It has also been reporte...Deregulation of the phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt)- mammalian target of rapamycin(m TOR) signaling pathway is one of the most commonlyinvolved pathways in tumorigenesis. It has also been reported as altered in neuroendocrine tumors(NETs). m TOR inhibitors used in clinical practice are derived from rapamycin,an anti-cancer agent also used as an immunosuppressor after organ transplantation. Everolimus and temsirolimus are the two rapamycin-derived m TOR inhibitors used in NETs. Notably everolimus has been approved in advanced progressive well/moderatelydifferentiated pancreatic NETs(p NETs). It inhibits specifically the m TORC1 subunit of m TOR,not interacting with m TORC2. Although everolimus produced a significant prolongation of progression-free survival a number of patients with p NETs do not benefit from the drug due to early or late progression. Two supposed mechanisms of resistance to m TOR inhibitors are Akt and PI3 K activation,by means of m TORC2 and insulin growth factor(IGF)- IGF receptor signaling,respectively. BEZ235 is a multi-targeted inhibitor binding to PI3 K,m TORC1 and m TORC2,therefore potentially turning off all the supposed molecular targets of resistance to everolimus. The two clinical trials designed in p NETs were stopped early due to unmet statistical endpoint and the global clinical development of BEZ235 was also halted. Tolerability of this drug was challenging and conditioned the feasibility of therapy. The BEZ experience is an example of the huge difference between the preclinical and clinical setting and prompts us to pay more attention to the phase Ⅰ step of clinical development and the design of phase Ⅱ clinical trials.展开更多
文摘目的:探讨磷脂酰肌醇3激酶抑制剂LY294002对人胚胎干细胞定向分化为成熟胰岛素分泌细胞的影响。方法:体外通过5个阶段诱导人胚胎干细胞定向分化为胰岛素分泌细胞。分别给予尼克酰胺+B27(B27组)为对照组和尼克酰胺+LY294002(LY组)为实验组诱导胰岛素分泌细胞的成熟。显微镜下观察各阶段细胞形态变化,免疫荧光染色鉴定胰岛素、c-肽、生长抑素和胰高血糖素的表达。结果:第5阶段诱导14 d LY组胰岛素单染阳性率与B27组无统计学差别(P﹥0.05),但生长抑素和胰高血糖素单染阳性率,胰岛素/生长抑素共染率均低于B27组(P﹤0.05)。结论:在无血清培养体系下,磷脂酰肌醇3激酶抑制剂LY294002能够诱导人胚胎干细胞分化为更加成熟的胰岛素分泌细胞。
文摘Deregulation of the phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt)- mammalian target of rapamycin(m TOR) signaling pathway is one of the most commonlyinvolved pathways in tumorigenesis. It has also been reported as altered in neuroendocrine tumors(NETs). m TOR inhibitors used in clinical practice are derived from rapamycin,an anti-cancer agent also used as an immunosuppressor after organ transplantation. Everolimus and temsirolimus are the two rapamycin-derived m TOR inhibitors used in NETs. Notably everolimus has been approved in advanced progressive well/moderatelydifferentiated pancreatic NETs(p NETs). It inhibits specifically the m TORC1 subunit of m TOR,not interacting with m TORC2. Although everolimus produced a significant prolongation of progression-free survival a number of patients with p NETs do not benefit from the drug due to early or late progression. Two supposed mechanisms of resistance to m TOR inhibitors are Akt and PI3 K activation,by means of m TORC2 and insulin growth factor(IGF)- IGF receptor signaling,respectively. BEZ235 is a multi-targeted inhibitor binding to PI3 K,m TORC1 and m TORC2,therefore potentially turning off all the supposed molecular targets of resistance to everolimus. The two clinical trials designed in p NETs were stopped early due to unmet statistical endpoint and the global clinical development of BEZ235 was also halted. Tolerability of this drug was challenging and conditioned the feasibility of therapy. The BEZ experience is an example of the huge difference between the preclinical and clinical setting and prompts us to pay more attention to the phase Ⅰ step of clinical development and the design of phase Ⅱ clinical trials.
