Oncogenic mutations in the RAS family of small GTPases are commonly found in human cancers and they promote tumorigenesis by altering gene expression networks. We previously demonstrated that Casein Kinase 1α (CK1α), a member of the CK1 family of serine/threonine kinases, is post-transcriptionally upregulated by oncogenic RAS signaling. Here, we report that the CK1α mRNA contains an exceptionally long 5′-untranslated region (UTR) harbouring several translational control elements, implicating its involvement in translational regulation. We demonstrate that the CK1α 5′-UTR functions as an IRES element in HCT-116 colon cancer cells to promote cap-independent translation. Using tobramycin-affinity RNA-pulldown assays coupled with identification via mass spectrometry, we identified several CK1α 5′-UTR-binding proteins, including SFPQ. We show that RNA interference targeting SFPQ reduced CK1α protein abundance and partially blocked RAS-mutant colon cancer cell growth. Importantly, transcript and protein levels of SFPQ and other CK1α 5′-UTR-associated RNA-binding proteins (RBPs) are found to be elevated in early stages of RAS-mutant cancers, including colorectal and lung adenocarcinoma. Taken together, our study uncovers a previously unappreciated role of RBPs in promoting RAS-mutant cancer cell growth and their potential to serve as promising biomarkers as well as tractable therapeutic targets in cancers driven by oncogenic RAS.

While we made great strides in the early detection of a handful of cancers, many other cancers are still detected at fairly later stages, thus hindering the deployment of effective surgical or therapeutic intervention to change their dismal clinical outcomes. The arduous journey of cancer cells from the primary tumor to colonize distant secondary organs or tissues begins with their ability to activate or deactivate various cellular processes at will, including the autophagy machinery. In this review, we discuss how circulatory cancer cells from primary tumors could selectively mobilize different subsets of microRNAs (miRNAs) to enable autophagic recycling of nutrients during their search for secondary sites to colonize and to disable such cell survival programs once they have successfully established at distant organs or tissues. We also discuss how this new miRNA-autophagy-metastasis axis can be targeted by the emerging RNA Medicine toolkit.