CDC2-like (CLK) protein kinase inhibition as a novel targeted therapeutic strategy in prostate cancer

Simon Uzor,Sean R Porazinski,Masatoshi Hagiwara,Claire M Perks,Abdullah A Alqasem,Ian D Wilson,Kei Iida,Michael R Ladomery,Bethany Clark,Ling Li,Sebastian Oltean,Masahiko Ajiro

doi:10.1038/s41598-021-86908-6

Abstract

Dysregulation of alternative splicing is a feature of cancer, both in aetiology and progression. It occurs because of mutations in splice sites or sites that regulate splicing, or because of the altered expression and activity of splice factors and of splice factor kinases that regulate splice factor activity. Recently the CDC2-like kinases (CLKs) have attracted attention due to their increasing involvement in cancer. We measured the effect of the CLK inhibitor, the benzothiazole TG003, on two prostate cancer cell lines. TG003 reduced cell proliferation and increased apoptosis in PC3 and DU145 cells. Conversely, the overexpression of CLK1 in PC3 cells prevented TG003 from reducing cell proliferation. TG003 slowed scratch closure and reduced cell migration and invasion in a transwell assay. TG003 decisively inhibited the growth of a PC3 cell line xenograft in nude mice. We performed a transcriptomic analysis of cells treated with TG003. We report widespread and consistent changes in alternative splicing of cancer-associated genes including CENPE, ESCO2, CKAP2, MELK, ASPH and CD164 in both HeLa and PC3 cells. Together these findings suggest that targeting CLKs will provide novel therapeutic opportunities in prostate cancer.

Highlights

Dysregulation of alternative splicing is a feature of cancer, both in aetiology and progression
We recently demonstrated that inhibition of the splice factor kinase SRPK1 with the compound SPHINX reduces prostate cancer xenograft growth through an anti-angiogenic alteration of VEGFA splicing[11]
Interest in the CDC2-like (CLK) splice factor kinases has grown steadily as they are increasingly implicated in a wide range of developmental and pathological processes including prostate cancer

Summary

Introduction

Dysregulation of alternative splicing is a feature of cancer, both in aetiology and progression. The CLK2 gene is amplified in a significant proportion of breast tumours and its downregulation inhibits cancer cell growth in cell culture and xenografts. The targeting of CLK2 with the inhibitor T-025 in an allograft model of MYC-driven spontaneous breast cancer resulted in significant anti-tumour effects, including the induction of skipped exons, of apoptosis, and growth s uppression[28].

Results

Conclusion