A KRAS-responsive long non-coding RNA controls microRNA processing

Wild-type KRAS (KRAS(WT)) amplification has been shown to be a secondary means of KRAS activation in cancer and associated with poor survival. Nevertheless, the precise role of KRAS(WT) overexpression in lung cancer progression is largely unexplored. Here, we identify and characterize a KRAS-responsive lncRNA, KIMAT1 (ENSG00000228709) and show that it correlates with KRAS levels both in cell lines and in lung cancer specimens. Mechanistically, KIMAT1 is a MYC target and drives lung tumorigenesis by promoting the processing of oncogenic microRNAs (miRNAs) through DHX9 and NPM1 stabilization while halting the biogenesis of miRNAs with tumor suppressor function via MYC-dependent silencing of p21, a component of the Microprocessor Complex. KIMAT1 knockdown suppresses not only KRAS expression but also KRAS downstream signaling, thereby arresting lung cancer growth in vitro and in vivo. Taken together, this study uncovers a role for KIMAT1 in maintaining a positive feedback loop that sustains KRAS signaling during lung cancer progression and provides a proof of principle that interfering with KIMAT1 could be a strategy to hamper KRAS-induced tumorigenesis. Wild-type KRAS amplification is known to induce KRAS activation in cancer leading to poor prognostic outcomes. Here the authors identify a KRAS-responsive lncRNA, KIMAT1 that maintains KRAS signalling in lung cancer, suggesting that its targeting may prevent KRAS-driven tumourigenesis.

Automated summary

This study reveals the role of KIMAT1 in maintaining KRAS signaling in lung cancer progression, suggesting that targeting it may be a strategy to prevent KRAS-induced tumorigenesis.