A novel class of inhibitors that target SRSF10 and promote p53-mediated cytotoxicity on human colorectal cancer cells

Abstract

The elevated expression of the splicing regulator SRSF10 in metastatic colorectal cancer (CRC) stimulates the production of the pro-tumorigenic BCLAF1-L splice variant. We discovered a group of small molecules with an aminothiazole carboxamide core (GPS167, GPS192 and others) that decrease production of BCLAF1-L. While additional alternative splicing events regulated by SRSF10 are affected by GPS167/192 in HCT116 cells (e.g. in MDM4, WTAP, SLK1 and CLK1), other events are shifted in a SRSF10-independent manner (e.g. in MDM2, NAB2 and TRA2A). GPS167/192 increased the interaction of SRSF10 with the CLK1 and CLK4 kinases, leading us to show that GPS167/192 can inhibit CLK kinases preferentially impacting the activity of SRSF10. Notably, GPS167 impairs the growth of CRC cell lines and organoids, inhibits anchorage-independent colony formation, cell migration, and promotes cytoxicity in a manner that requires SRSF10 and p53. In contrast, GPS167 only minimally affects normal colonocytes and normal colorectal organoids. Thus, GPS167 reprograms the tumorigenic activity of SRSF10 in CRC cells to elicit p53-dependent apoptosis.

Comparative Efficacy and Selectivity of Pharmacological Inhibitors of DYRK and CLK Protein Kinases

“…GPS167 was discovered as an inhibitor of the phosphorylation (by CLKs) of the SRSF10 splicing factor, thereby altering the alternative splicing of BCLAF1 and leading to a reduced production of the BCLAF1-L pro-oncogenic form, which consequently promoted the death of colorectal cancer cell lines. 133 Although reported as a modest inhibitor (>10 μM) of CLK1, CLK2, and CLK4 in vitro with recombinant SRSF1 or SRSF10 as substrates, 133 In cells, the lowest concentration (1 μM) led to an increase in Thr212-Tau phosphorylation, the middle concentration (10 μM) led to two distinct phospho-Thr212-Tau bands, and the highest concentration (30 μM) led to the disappearance of almost all signal (Figure S1). ID-8 (44).…”

MYC regulates a pan-cancer network of co-expressed oncogenic splicing factors

“…SFs are being investigated as therapeutic targets in preclinical or clinical trials testing small molecules that target the splicing machinery, 1 directly inhibit specific SFs, 8 or target SF stability. 93 Further, SF activity and localization are often controlled by phosphorylation, 94 and inhibition of upstream kinases to diminish activity of oncogenic SFs 95 – 99 should be tested in MYC-driven tumors. Finally, RNA-based approaches to modulate the expression of SR proteins have revealed a therapeutic window for targeting SFs in cancer without notable toxicity in normal cells.…”

Splicing factor-mediated regulation patterns reveals biological characteristics and aid in predicting prognosis in acute myeloid leukemia

“…For instance, it promotes the production of the cancer-promoting splice variant BCLAF1-L [ 32 ]. It regulates the alternative splicing of cancer-related transcripts MDM4 and SLK in HCT116 cells [ 33 ]. SRSF10 upregulates the production of a circular RNA (CIRC-ATXN1) that plays a role in glioma angiogenesis by sequestrating mir-526b-3p, which normally inhibits the expression of pro-angiogenic MMP2 and VEGFA [ 34 ].…”