m6A methylation of circKPNA2 drives colorectal cancer progression by activating the RIN1-Ras pathway

Colorectal cancer (CRC) remains a highly prevalent and lethal malignancy, with current treatments often limited by incomplete understanding of its molecular progression. A critical gap exists in identifying novel drivers and actionable targets beyond established pathways. Emerging research highlights the importance of non-coding RNAs, such as circular RNAs (circRNAs), and epigenetic modifications like N6-methyladenosine (m6A) methylation in cancer biology. This study investigates how a specific circRNA, circKPNA2, contributes to CRC development and identifies its regulatory mechanisms, offering new insights into disease pathogenesis.

Researchers investigated the role of circKPNA2 in colorectal cancer progression using a suite of advanced techniques. They examined circKPNA2 expression and function in CRC tissues and cell lines. Methodologies included RNA sequencing to identify expression profiles, functional assays to assess cell proliferation, migration, and invasion, RNA pull-down to identify binding partners, and mass spectrometry for protein identification. The study aimed to elucidate how circKPNA2 interacts with other cellular components and influences key oncogenic pathways.

The study revealed that circKPNA2 is significantly upregulated in colorectal cancer tissues and cell lines. This upregulation directly contributes to tumor growth by promoting CRC cell proliferation, migration, and invasion. Mechanistically, circKPNA2 was found to specifically bind to the RIN1 protein, leading to increased RIN1 levels. This interaction subsequently activates the Ras signalling pathway, a well-known driver of cancer progression. Furthermore, the researchers identified that METTL3, a key m6A methyltransferase, regulates the expression of circKPNA2 through N6-methyladenosine (m6A) methylation. This m6A-mediated regulation of circKPNA2 directly impacts CRC cell proliferation, migration, and invasion.

circKPNA2 specifically binds to the RIN1 protein and increases its levels, thereby activating the Ras signalling pathway and facilitating CRC progression. These findings underscore a novel circKPNA2-RIN1-Ras axis in CRC progression, regulated by m6A methylation.