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
Sweet sorghum mutants induced by^(12)C(6+)-ion irradiation were planted under different soil salinity conditions to investigate the mechanisms maintaining the transport and spatial distribution of Na^+. The functions ...Sweet sorghum mutants induced by^(12)C(6+)-ion irradiation were planted under different soil salinity conditions to investigate the mechanisms maintaining the transport and spatial distribution of Na^+. The functions of the synergistic responses of NHX, AKT1, and SOS1 related to Na^+ accumulation were investigated in control(KFJT-CK) sorghum and KF1210-3 and KF1210-4 mutants. The results indicated that the NHX, AKT1, and SOS1 proteins in sweet sorghum are mainly involved in the transport, exclusion, and spatial distribution of Na^+,respectively. In addition to physiological parameters, we also measured the expression levels of NHX, AKT1, and SOS1 genes. The experimental results indicated that 150 m M Na Cl induced marked increases in the transcripts of NHX and SOS1 after 8 and 12 h in the KF1210-3,KF1210-4, and KFJT-CK cultivars. In contrast, however, a decrease in AKT1 was observed. On the basis of our results, we propose a model in which cooperation amongNHX, AKT1, and SOS1 facilitates Na^+ homeostasis in sweet sorghum in response to an increase in salt concentration. Accordingly, study of the regulatory mechanisms in sweet sorghum generated by carbon ion irradiation is essential for the selection of salt-tolerant cultivars.展开更多
目的Rasfonin是一种从青藏高原海拔>4 km土壤样品的真菌中发酵提取的α-吡喃酮类化合物。前期研究表明,Rasfonin可下调SOS1(Son of sevenless)蛋白表达以及由其介导的RAS蛋白核酸交换反应,但作用机理尚不明确。本研究拟探讨Rasfonin...目的Rasfonin是一种从青藏高原海拔>4 km土壤样品的真菌中发酵提取的α-吡喃酮类化合物。前期研究表明,Rasfonin可下调SOS1(Son of sevenless)蛋白表达以及由其介导的RAS蛋白核酸交换反应,但作用机理尚不明确。本研究拟探讨Rasfonin对SOS1表达的调控以及KRAS蛋白在其中的参与作用,以期进一步阐述Rasfonin的抑癌机制,为抗肿瘤新药的研究提供实验依据。方法在野生型KRAS^(WT)、突变型KRAS^(G12C)和KRAS^(G12D)的人源肿瘤细胞上观察Rasfonin对SOS1表达的作用,应用Western印迹法和实时荧光定量PCR检测SOS1蛋白和mRNA表达;采用双荧光素酶报告基因实验测定SOS1启动子活性;在此基础上,将KRAS^(WT)、KRAS^(G12D)、KRAS^(G12C)和SOS1质粒转染293T细胞构建KRAS与SOS1共表达体系来探讨KRAS在Rasfonin抑制SOS1表达过程中的作用。结果Rasfonin的阴性对照化合物A321不影响SOS1蛋白表达。Rasfonin作用后,KRAS野生型细胞SOS1蛋白表达量不变,mRNA短暂升高后恢复至对照水平,而突变型细胞SOS1蛋白表达量明显减少(P<0.05),mRNA短暂升高后显著降低(P<0.05)。293T细胞中无KRAS蛋白时,Rasfonin对SOS1启动子活性无影响,而转染KRAS(WT,G12C和G12D)质粒后,Rasfonin明显抑制SOS1启动子活性(P<0.05)。单转染SOS1及其与野生型KRAS共转染时,Rasfonin仅轻微下调SOS1蛋白表达;而共转染SOS1与突变型KRAS(G12C和G12D)时,Rasfonin可显著抑制SOS1蛋白表达(P<0.05)。结论Rasfonin可能通过突变型KRAS(G12C和G12D)蛋白抑制SOS1的启动子活性,进而选择性下调突变型KRAS^(G12C)和KRAS^(G12D)肿瘤细胞中SOS1 mRNA及蛋白的表达水平。本课题深化了对Rasfonin抑癌机制及SOS1表达调控的认识,为RAS突变肿瘤的治疗提供了新的思路。展开更多
The lignocellulosic crop Miscanthus spp.has been identified as a good candidate for biomass production.The responses of Miscanthus sinensis Anderss.to salinity were studied to satisfy the needs for high yields in marg...The lignocellulosic crop Miscanthus spp.has been identified as a good candidate for biomass production.The responses of Miscanthus sinensis Anderss.to salinity were studied to satisfy the needs for high yields in marginal areas and to avoid competition with food production.The results indicated that the relative advantages of the tolerant accession over the sensitive one under saline conditions were associated with restricted Na^(+)accumulation in shoots.Seedlings of two accessions(salt-tolerant‘JM0119’and salt-sensitive‘JM0099’)were subjected to 0(control),100,200,and 300 mM NaCl stress to better understand the salt-induced biochemical responses of genes involved in Na^(+)accumulation in M.sinensis.The adaptation responses of genes encoding for Na^(+)/H^(+)antiporters,NHX1 and SOS1 to NaCl stress were examined in JM0119 and JM0099.The cDNA sequences of genes examined were highly conserved among the relatives of M.sinensis based on the sequencing on approximate 600 bp-long cDNA fragments obtained from degenerate PCR.These salt-induced variations of gene expression investigated by quantitative real-time PCR provided evidences for insights of the molecular mechanisms of salt tolerance in M.sinensis.The expression of NHX1 was up-regulated by salt stress in JM0119 shoot and root tissues.However,it was hardly affected in JM0099 shoot tissue except for a significant increase at the 100 mM salt treatment,and it was salt-suppressed in the JM0099 root tissue.In the root tissue,the expression of SOS1 was induced by the high salt treatment in JM0119 but repressed by all salt treatments in JM0099.Thus,the remarkably higher expression of NHX1 and SOS1 were associated with the resistance to Na^(+)toxicity by regulation of the Na^(+)influx,efflux,and sequestration under different salt conditions.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.
基金supported by the Science and Technology Service Network Initiative(STS)program of the Chinese Academy of Sciences(CAS)(KFJ-EW-STS-086)the National Natural Science Foundation of China(No.11275171)+1 种基金the CAS‘‘Light of West China’’ Program(Nos.29Y506020 and 29Y406020)the Youth Innovation Promotion Association of CAS(No.2015337)
文摘Sweet sorghum mutants induced by^(12)C(6+)-ion irradiation were planted under different soil salinity conditions to investigate the mechanisms maintaining the transport and spatial distribution of Na^+. The functions of the synergistic responses of NHX, AKT1, and SOS1 related to Na^+ accumulation were investigated in control(KFJT-CK) sorghum and KF1210-3 and KF1210-4 mutants. The results indicated that the NHX, AKT1, and SOS1 proteins in sweet sorghum are mainly involved in the transport, exclusion, and spatial distribution of Na^+,respectively. In addition to physiological parameters, we also measured the expression levels of NHX, AKT1, and SOS1 genes. The experimental results indicated that 150 m M Na Cl induced marked increases in the transcripts of NHX and SOS1 after 8 and 12 h in the KF1210-3,KF1210-4, and KFJT-CK cultivars. In contrast, however, a decrease in AKT1 was observed. On the basis of our results, we propose a model in which cooperation amongNHX, AKT1, and SOS1 facilitates Na^+ homeostasis in sweet sorghum in response to an increase in salt concentration. Accordingly, study of the regulatory mechanisms in sweet sorghum generated by carbon ion irradiation is essential for the selection of salt-tolerant cultivars.
文摘目的Rasfonin是一种从青藏高原海拔>4 km土壤样品的真菌中发酵提取的α-吡喃酮类化合物。前期研究表明,Rasfonin可下调SOS1(Son of sevenless)蛋白表达以及由其介导的RAS蛋白核酸交换反应,但作用机理尚不明确。本研究拟探讨Rasfonin对SOS1表达的调控以及KRAS蛋白在其中的参与作用,以期进一步阐述Rasfonin的抑癌机制,为抗肿瘤新药的研究提供实验依据。方法在野生型KRAS^(WT)、突变型KRAS^(G12C)和KRAS^(G12D)的人源肿瘤细胞上观察Rasfonin对SOS1表达的作用,应用Western印迹法和实时荧光定量PCR检测SOS1蛋白和mRNA表达;采用双荧光素酶报告基因实验测定SOS1启动子活性;在此基础上,将KRAS^(WT)、KRAS^(G12D)、KRAS^(G12C)和SOS1质粒转染293T细胞构建KRAS与SOS1共表达体系来探讨KRAS在Rasfonin抑制SOS1表达过程中的作用。结果Rasfonin的阴性对照化合物A321不影响SOS1蛋白表达。Rasfonin作用后,KRAS野生型细胞SOS1蛋白表达量不变,mRNA短暂升高后恢复至对照水平,而突变型细胞SOS1蛋白表达量明显减少(P<0.05),mRNA短暂升高后显著降低(P<0.05)。293T细胞中无KRAS蛋白时,Rasfonin对SOS1启动子活性无影响,而转染KRAS(WT,G12C和G12D)质粒后,Rasfonin明显抑制SOS1启动子活性(P<0.05)。单转染SOS1及其与野生型KRAS共转染时,Rasfonin仅轻微下调SOS1蛋白表达;而共转染SOS1与突变型KRAS(G12C和G12D)时,Rasfonin可显著抑制SOS1蛋白表达(P<0.05)。结论Rasfonin可能通过突变型KRAS(G12C和G12D)蛋白抑制SOS1的启动子活性,进而选择性下调突变型KRAS^(G12C)和KRAS^(G12D)肿瘤细胞中SOS1 mRNA及蛋白的表达水平。本课题深化了对Rasfonin抑癌机制及SOS1表达调控的认识,为RAS突变肿瘤的治疗提供了新的思路。
基金This study was supported by grants from Shenzhen Fundamental Research Program(Grant Nos.JCYJ20170818140058675 and JCYJ20170818140127741)Natural Science Foundation of Top Talent of SZTU(Grant Nos.2019010801010 and 2019010801009).
文摘The lignocellulosic crop Miscanthus spp.has been identified as a good candidate for biomass production.The responses of Miscanthus sinensis Anderss.to salinity were studied to satisfy the needs for high yields in marginal areas and to avoid competition with food production.The results indicated that the relative advantages of the tolerant accession over the sensitive one under saline conditions were associated with restricted Na^(+)accumulation in shoots.Seedlings of two accessions(salt-tolerant‘JM0119’and salt-sensitive‘JM0099’)were subjected to 0(control),100,200,and 300 mM NaCl stress to better understand the salt-induced biochemical responses of genes involved in Na^(+)accumulation in M.sinensis.The adaptation responses of genes encoding for Na^(+)/H^(+)antiporters,NHX1 and SOS1 to NaCl stress were examined in JM0119 and JM0099.The cDNA sequences of genes examined were highly conserved among the relatives of M.sinensis based on the sequencing on approximate 600 bp-long cDNA fragments obtained from degenerate PCR.These salt-induced variations of gene expression investigated by quantitative real-time PCR provided evidences for insights of the molecular mechanisms of salt tolerance in M.sinensis.The expression of NHX1 was up-regulated by salt stress in JM0119 shoot and root tissues.However,it was hardly affected in JM0099 shoot tissue except for a significant increase at the 100 mM salt treatment,and it was salt-suppressed in the JM0099 root tissue.In the root tissue,the expression of SOS1 was induced by the high salt treatment in JM0119 but repressed by all salt treatments in JM0099.Thus,the remarkably higher expression of NHX1 and SOS1 were associated with the resistance to Na^(+)toxicity by regulation of the Na^(+)influx,efflux,and sequestration under different salt conditions.
