TLK1‐mediated MK5‐S354 phosphorylation drives prostate cancer cell motility and may signify distinct pathologies. Issue 13 (3rd February 2022)

• Record Type: Journal Article
• Authors: Khalil, Md Imtiaz; Singh, Vibha; King, Judy; De Benedetti, Arrigo
• Is Part Of: Molecular oncology. Volume 16:Issue 13(2022)
• Page Start: 2537
• Page End: 2557
• Publication Date: 2022-02-03
• Subjects: cell motility -- MK5/MAPKAPK5/PRAK -- PCa TMA -- prostate cancer metastasis -- TLK1/1B; Cancer -- Molecular aspects -- Periodicals; 616.994005
• DOI: 10.1002/1878-0261.13183
• Languages: English
• ISSNs: 1574-7891

Abstract

Abstract : Metastases account for the majority of prostate cancer (PCa) deaths, and targeting them is a major goal of systemic therapy. We identified a novel interaction between two kinases: tousled‐like kinase 1 (TLK1) and MAP kinase‐activated protein kinase 5 (MK5) that promotes PCa spread. In PCa progression, TLK1–MK5 signalling appears to increase following antiandrogen treatment and in metastatic castration‐resistant prostate cancer (mCRPC) patients. Determinations of motility rates (2D and 3D) of different TLK1‐ and MK5‐perturbed cells, including knockout (KO) and knockdown (KD), as well as the use of specific inhibitors, showed the importance of these two proteins for in vitro dissemination. We established that TLK1 phosphorylates MK5 on three residues (S160, S354 and S386), resulting in MK5 activation, and additionally, mobility shifts of MK5 also supported its phosphorylation by TLK1 in transfected HEK 293 cells. Expression of MK5‐S354A or kinase‐dead MK5 in MK5‐depleted mouse embryonic fibroblast (MEF) cells failed to restore their motility compared with that of wild‐type (WT) MK5‐rescued MK5 −/− MEF cells. A pMK5‐S354 antiserum was used to establish this site as an authentic TLK1 target in androgen‐sensitive human prostate adenocarcinoma (LNCaP) cells, and was used in immunohistochemistry (IHC) studies of age‐related PCa sections from TRAMP (transgenic adenocarcinoma of the mouse prostate) mice and to probe a human tissue microarray (TMA), which revealed pMK5‐S354 level is correlated with disease progression (Gleason score and nodal metastases). In addition, The Cancer Genome Atlas (TCGA) analyses of PCa expression and genome‐wide association study (GWAS) relations identify TLK1 and MK5 as potential drivers of advanced PCa and as markers of mCRPC. Our work suggests that TLK1–MK5 signalling is functionally involved in driving PCa cell motility and clinical features of aggressiveness; hence, disruption of this axis may inhibit the metastatic spread of PCa. Abstract : Targeting metastasis in prostate cancer (PCa) remains a major challenge during systemic therapy. Here, we describe a novel interaction between the TLK1 and MK5 kinases, which resulted in activation and cytoplasmic relocalization of MK5 via MK5‐S354 phosphorylation. Knockout and pharmacological inhibition of MK5 impaired motility and invasion of PCa and MEF cells. Additionally, MK5‐S354 phosphorylation correlated with PCa progression in a TRAMP mouse model and correlated to disease progression in patients with PCa. Thus, disruption of the TLK1‐MK5 axis may inhibit the metastatic spread of PCa.