Kobayashi Yoshihisa, Chhoeu Chhayheng, Li Jiaqi, Price Kristin S, Kiedrowski Lesli A, Hutchins Jamie L, Hardin Aaron I, Wei Zihan, Hong Fangxin, Bahcall Magda, Gokhale Prafulla C, Jänne Pasi A
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
Department of Medicine, Harvard Medical School, Boston, MA, USA.
Nature. 2022 Mar;603(7900):335-342. doi: 10.1038/s41586-022-04451-4. Epub 2022 Mar 2.
RAS family members are the most frequently mutated oncogenes in human cancers. Although KRAS(G12C)-specific inhibitors show clinical activity in patients with cancer, there are no direct inhibitors of NRAS, HRAS or non-G12C KRAS variants. Here we uncover the requirement of the silent KRAS mutation for cells to produce a functional KRAS(Q61K). In the absence of this G60G mutation in KRAS, a cryptic splice donor site is formed, promoting alternative splicing and premature protein termination. A G60G silent mutation eliminates the splice donor site, yielding a functional KRAS(Q61K) variant. We detected a concordance of KRAS and a G60G/A59A silent mutation in three independent pan-cancer cohorts. The region around RAS Q61 is enriched in exonic splicing enhancer (ESE) motifs and we designed mutant-specific oligonucleotides to interfere with ESE-mediated splicing, rendering the RAS(Q61) protein non-functional in a mutant-selective manner. The induction of aberrant splicing by antisense oligonucleotides demonstrated therapeutic effects in vitro and in vivo. By studying the splicing necessary for a functional KRAS(Q61K), we uncover a mutant-selective treatment strategy for RAS cancer and expose a mutant-specific vulnerability, which could potentially be exploited for therapy in other genetic contexts.
RAS家族成员是人类癌症中最常发生突变的致癌基因。尽管KRAS（G12C）特异性抑制剂在癌症患者中显示出临床活性，但目前尚无针对NRAS、HRAS或非G12C KRAS变体的直接抑制剂。在这里，我们发现了沉默的KRAS突变对于细胞产生功能性KRAS（Q61K）的必要性。在KRAS基因中不存在这种G60G突变的情况下，会形成一个隐蔽的剪接供体位点，促进可变剪接和蛋白质过早终止。G60G沉默突变消除了剪接供体位点，产生了功能性的KRAS（Q61K）变体。我们在三个独立的泛癌队列中检测到KRAS与G60G/A59A沉默突变的一致性。RAS Q61周围区域富含外显子剪接增强子（ESE）基序，我们设计了突变体特异性寡核苷酸来干扰ESE介导的剪接，以突变体选择性的方式使RAS（Q61）蛋白失去功能。反义寡核苷酸诱导的异常剪接在体外和体内均显示出治疗效果。通过研究功能性KRAS（Q61K）所需的剪接，我们发现了一种针对RAS癌症的突变体选择性治疗策略，并揭示了一种突变体特异性的脆弱性，这可能在其他遗传背景下被用于治疗。
