PDF(Pubmed)
Abstract：
BACKGROUND: KRAS mutations frequently occur in cancers, particularly pancreatic ductal adenocarcinoma, colorectal cancer, and non-small cell lung cancer. Although KRASG12C inhibitors have recently been approved, effective precision therapies have not yet been established for all KRAS-mutant cancers. Many treatments for KRAS-mutant cancers, including epigenome-targeted drugs, are currently under investigation. Small ubiquitin-like modifier (SUMO) proteins are a family of small proteins covalently attached to and detached from other proteins in cells via the processes called SUMOylation and de-SUMOylation. We assessed whether SUMOylation inhibition was effective in KRAS-mutant cancer cells.
METHODS: The efficacy of the first-in-class SUMO-activating enzyme E inhibitor TAK-981 (subasumstat) was assessed in multiple human and mouse KRAS-mutated cancer cell lines. A gene expression assay using a TaqMan array was used to identify biomarkers of TAK-981 efficacy. The biological roles of SUMOylation inhibition and subsequent regulatory mechanisms were investigated using immunoblot analysis, immunofluorescence assays, and mouse models.
RESULTS: We discovered that TAK-981 downregulated the expression of the currently undruggable MYC and effectively suppressed the growth of MYC-expressing KRAS-mutant cancers across different tissue types. Moreover, TAK-981-resistant cells were sensitized to SUMOylation inhibition via MYC-overexpression. TAK-981 induced proteasomal degradation of MYC by altering the balance between SUMOylation and ubiquitination and promoting the binding of MYC and Fbxw7, a key factor in the ubiquitin-proteasome system. The efficacy of TAK-981 monotherapy in immunocompetent and immunodeficient mouse models using a mouse-derived CMT167 cell line was significant but modest. Since MAPK inhibition of the KRAS downstream pathway is crucial in KRAS-mutant cancer, we expected that co-inhibition of SUMOylation and MEK might be a good option. Surprisingly, combination treatment with TAK-981 and trametinib dramatically induced apoptosis in multiple cell lines and gene-engineered mouse-derived organoids. Moreover, combination therapy resulted in long-term tumor regression in mouse models using cell lines of different tissue types. Finally, we revealed that combination therapy complementally inhibited Rad51 and BRCA1 and accumulated DNA damage.
CONCLUSIONS: We found that MYC downregulation occurred via SUMOylation inhibition in KRAS-mutant cancer cells. Our findings indicate that dual inhibition of SUMOylation and MEK may be a promising treatment for MYC-expressing KRAS-mutant cancers by enhancing DNA damage accumulation.
METHODS: The efficacy of the first-in-class SUMO-activating enzyme E inhibitor TAK-981 (subasumstat) was assessed in multiple human and mouse KRAS-mutated cancer cell lines. A gene expression assay using a TaqMan array was used to identify biomarkers of TAK-981 efficacy. The biological roles of SUMOylation inhibition and subsequent regulatory mechanisms were investigated using immunoblot analysis, immunofluorescence assays, and mouse models.
RESULTS: We discovered that TAK-981 downregulated the expression of the currently undruggable MYC and effectively suppressed the growth of MYC-expressing KRAS-mutant cancers across different tissue types. Moreover, TAK-981-resistant cells were sensitized to SUMOylation inhibition via MYC-overexpression. TAK-981 induced proteasomal degradation of MYC by altering the balance between SUMOylation and ubiquitination and promoting the binding of MYC and Fbxw7, a key factor in the ubiquitin-proteasome system. The efficacy of TAK-981 monotherapy in immunocompetent and immunodeficient mouse models using a mouse-derived CMT167 cell line was significant but modest. Since MAPK inhibition of the KRAS downstream pathway is crucial in KRAS-mutant cancer, we expected that co-inhibition of SUMOylation and MEK might be a good option. Surprisingly, combination treatment with TAK-981 and trametinib dramatically induced apoptosis in multiple cell lines and gene-engineered mouse-derived organoids. Moreover, combination therapy resulted in long-term tumor regression in mouse models using cell lines of different tissue types. Finally, we revealed that combination therapy complementally inhibited Rad51 and BRCA1 and accumulated DNA damage.
CONCLUSIONS: We found that MYC downregulation occurred via SUMOylation inhibition in KRAS-mutant cancer cells. Our findings indicate that dual inhibition of SUMOylation and MEK may be a promising treatment for MYC-expressing KRAS-mutant cancers by enhancing DNA damage accumulation.
摘要：
背景：KRAS突变经常发生在癌症中，尤其是胰腺导管腺癌，结直肠癌,和非小细胞肺癌。尽管最近批准了KRASG12C抑制剂，对于所有KRAS突变癌症,目前尚未建立有效的精准治疗.KRAS突变癌症的许多治疗方法，包括表观基因组靶向药物，目前正在调查中。小泛素样修饰蛋白（SUMO）是通过称为SUMO化和去SUMO化的过程与细胞中的其他蛋白质共价连接并分离的小蛋白质家族。我们评估了SUMO化抑制在KRAS突变的癌细胞中是否有效。
方法：在多种人和小鼠KRAS突变的癌细胞系中评估了第一类SUMO激活酶E抑制剂TAK-981（subasumstat）的功效。使用TaqMan阵列的基因表达测定用于鉴定TAK-981功效的生物标志物。使用免疫印迹分析研究了SUMO化抑制的生物学作用和随后的调节机制，免疫荧光测定，和老鼠模型。
结果：我们发现TAK-981下调了目前无法用药的MYC的表达，并有效抑制了不同组织类型中表达MYC的KRAS突变癌症的生长。此外，通过MYC过表达使TAK-981抗性细胞对SUMO化抑制敏感。TAK-981通过改变SUMO化和泛素化之间的平衡并促进泛素-蛋白酶体系统中的关键因素MYC和Fbxw7的结合来诱导MYC的蛋白酶体降解。在使用小鼠来源的CMT167细胞系的免疫活性和免疫缺陷小鼠模型中,TAK-981单一疗法的功效是显著的但适度的。由于MAPK抑制KRAS下游途径在KRAS突变癌症中至关重要，我们预计SUMO化和MEK的共同抑制可能是一个很好的选择。令人惊讶的是,TAK-981和曲美替尼联合治疗可显著诱导多种细胞系和基因工程小鼠来源的类器官细胞凋亡.此外，在使用不同组织类型的细胞系的小鼠模型中,联合治疗导致肿瘤长期消退.最后,我们发现联合治疗可补充抑制Rad51和BRCA1并累积DNA损伤.
结论：我们发现在KRAS突变的癌细胞中，MYC通过SUMO化抑制发生下调。我们的发现表明，SUMO化和MEK的双重抑制可能是通过增强DNA损伤积累来治疗表达MYC的KRAS突变癌症的有希望的治疗方法。
方法：在多种人和小鼠KRAS突变的癌细胞系中评估了第一类SUMO激活酶E抑制剂TAK-981（subasumstat）的功效。使用TaqMan阵列的基因表达测定用于鉴定TAK-981功效的生物标志物。使用免疫印迹分析研究了SUMO化抑制的生物学作用和随后的调节机制，免疫荧光测定，和老鼠模型。
结果：我们发现TAK-981下调了目前无法用药的MYC的表达，并有效抑制了不同组织类型中表达MYC的KRAS突变癌症的生长。此外，通过MYC过表达使TAK-981抗性细胞对SUMO化抑制敏感。TAK-981通过改变SUMO化和泛素化之间的平衡并促进泛素-蛋白酶体系统中的关键因素MYC和Fbxw7的结合来诱导MYC的蛋白酶体降解。在使用小鼠来源的CMT167细胞系的免疫活性和免疫缺陷小鼠模型中,TAK-981单一疗法的功效是显著的但适度的。由于MAPK抑制KRAS下游途径在KRAS突变癌症中至关重要，我们预计SUMO化和MEK的共同抑制可能是一个很好的选择。令人惊讶的是,TAK-981和曲美替尼联合治疗可显著诱导多种细胞系和基因工程小鼠来源的类器官细胞凋亡.此外，在使用不同组织类型的细胞系的小鼠模型中,联合治疗导致肿瘤长期消退.最后,我们发现联合治疗可补充抑制Rad51和BRCA1并累积DNA损伤.
结论：我们发现在KRAS突变的癌细胞中，MYC通过SUMO化抑制发生下调。我们的发现表明，SUMO化和MEK的双重抑制可能是通过增强DNA损伤积累来治疗表达MYC的KRAS突变癌症的有希望的治疗方法。
