The Kirsten rat sarcoma virus—son of sevenless 1(KRAS-SOS1)axis drives tumor growth preferentially in pancreatic,colon,and lung cancer.Now,KRAS G12C mutated tumors can be successfully treated with inhibitors that cov...The Kirsten rat sarcoma virus—son of sevenless 1(KRAS-SOS1)axis drives tumor growth preferentially in pancreatic,colon,and lung cancer.Now,KRAS G12C mutated tumors can be successfully treated with inhibitors that covalently block the cysteine of the switch II binding pocket of KRAS.However,the range of other KRAS mutations is not amenable to treatment and the G12C-directed agents Sotorasib and Adragrasib show a response rate of only approximately 40%,lasting for a mean period of 8 months.One approach to increase the efficacy of inhibitors is their inclusion into proteolysis-targeting chimeras(PROTACs),which degrade the proteins of interest and exhibit much higher antitumor activity through multiple cycles of activity.Accordingly,PROTACs have been developed based on KRAS-or SOS1-directed inhibitors coupled to either von Hippel-Lindau(VHL)or Cereblon(CRBN)ligands that invoke the proteasomal degradation.Several of these PROTACs show increased activity in vitro and in vivo compared to their cognate inhibitors but their toxicity in normal tissues is not clear.The CRBN PROTACs containing thalidomide derivatives cannot be tested in experimental animals.Resistance to such PROTACS arises through downregulation or inactivation of CRBN or factors of the functional VHL E3 ubiquitin ligase.Although highly active KRAS and SOS1 PROTACs have been formulated their clinical application remains difficult.展开更多
目的建立用于筛选具有抗肿瘤活性的沙利度胺衍生物的分子平台。方法从人胎肝c DNA文库中分别扩增cereblon(CRBN)和Ikaros家族锌指蛋白1(Ikaros family zinc finger protein 1,IKZF1)c DNA,并将其克隆入p XJ40-myc和pc DNA3-FLAG载体中,...目的建立用于筛选具有抗肿瘤活性的沙利度胺衍生物的分子平台。方法从人胎肝c DNA文库中分别扩增cereblon(CRBN)和Ikaros家族锌指蛋白1(Ikaros family zinc finger protein 1,IKZF1)c DNA,并将其克隆入p XJ40-myc和pc DNA3-FLAG载体中,将其转染293T细胞,通过检测沙利度胺及其衍生物对CRBN和IKZF1蛋白相互作用的改变,间接反映其在肿瘤抑制中的作用。结果 CRBN和IKZF1在293T细胞中均得到表达,沙利度胺及其两个衍生物可显著增强CRBN和IKZF1的结合。结论成功建立了用于筛选具有抗肿瘤活性的沙利度胺衍生物分子平台,初步发现2个沙利度胺衍生物可显著增强CRBN和IKZF1的结合,提示其具有潜在的抗癌活性。展开更多
文摘The Kirsten rat sarcoma virus—son of sevenless 1(KRAS-SOS1)axis drives tumor growth preferentially in pancreatic,colon,and lung cancer.Now,KRAS G12C mutated tumors can be successfully treated with inhibitors that covalently block the cysteine of the switch II binding pocket of KRAS.However,the range of other KRAS mutations is not amenable to treatment and the G12C-directed agents Sotorasib and Adragrasib show a response rate of only approximately 40%,lasting for a mean period of 8 months.One approach to increase the efficacy of inhibitors is their inclusion into proteolysis-targeting chimeras(PROTACs),which degrade the proteins of interest and exhibit much higher antitumor activity through multiple cycles of activity.Accordingly,PROTACs have been developed based on KRAS-or SOS1-directed inhibitors coupled to either von Hippel-Lindau(VHL)or Cereblon(CRBN)ligands that invoke the proteasomal degradation.Several of these PROTACs show increased activity in vitro and in vivo compared to their cognate inhibitors but their toxicity in normal tissues is not clear.The CRBN PROTACs containing thalidomide derivatives cannot be tested in experimental animals.Resistance to such PROTACS arises through downregulation or inactivation of CRBN or factors of the functional VHL E3 ubiquitin ligase.Although highly active KRAS and SOS1 PROTACs have been formulated their clinical application remains difficult.
