Characterization of Kinase Expression Related to Increased Migration of PC-3M Cells Using Global Comparative Phosphoproteome Analysis

Abstract

Background/Aim: Prostate cancer (PCa) is the second-most commonly occurring cancer among men, worldwide. Although the mechanisms associated with the progression of castration-resistant prostate cancer (CRPC) have been widely studied, the mechanism associated with more distant metastases from the bone remains unknown. This study aimed to characterize potential pathogenic kinases associated with highly metastatic PCa, that may regulate phosphorylation in extensively involved and diverse signaling pathways that are associated with the development of various cancers. Materials and Methods: A mass spectrometry (MS)based comparative phosphoproteome strategy was utilized to identify differentially expressed kinases between the highly aggressive PCa cell-lines PC-3 and PC-3M. Results: Among 2,968 phosphorylation sites in PCa cells, 151 differently expressed phosphoproteins were identified. Seven motifs:-SP- ,-SxxE- ,-PxS- ,-PxSP- ,-SxxK- ,-SPxK-, and-SxxxxxP-were found to be highly expressed in PC-3M cells. Based on these motifs, the kinases p21-activated kinase (PAK)2, Ste20-like kinase (SLK), mammalian Ste20-like kinase (MST)4, mitogenactivated kinase kinase (MAP2K)2, and A-Raf proto-oncogene serine/threonine kinase (ARAF) were up-regulated in PC-3M cells. Conclusion: PAK2, SLK, MST4, MAP2K2, and ARAF are kinases that are potentially associated with the progression of increased migration in PC-3M cells and may represent molecule regulators or drug targets for highly metastatic PCa therapy. Prostate cancer (PCa) is the second-most commonly occurring cancer among men, worldwide (1, 2). According to the latest report by the American Cancer Society, in 2020, 191,930 new cases of PCa will be diagnosed and 33,330 individuals will die from PCa, in the United States (3). Unlike other types of cancers, PCa grows very slowly and may not cause symptoms for years, until the cancer cells metastasize out of the prostate, developing to advanced PCa (4, 5). This characteristic has limited most cases of PCa being recognized and treated during the early stages, and prostate-specific antigen technology began to be applied to the detection of primary-stage PCa in 1994 (6, 7). Because PCa is an androgen-dependent disease (8), androgen deprivation therapy is the standard therapy for the initial stages of advanced PCa; however, treatment can eventually result in the development of castration-resistant PCa (CRPC) (9). Androgen receptor (AR) inhibition remains a key factor in CRPC therapies. Metastatic CRPC (mCRPC) develops when PCa cells spread to other parts of the body, where they can grow and spread, even under medical treatment (10). According to the "seed and soil" theory, proposed by Paget (11), PCa spreads in the bloodstream as "seeds", which settle in specific organs, which represent 543 This article is freely accessible online.

Discovery of a Potent Dual SLK/STK10 Inhibitor Based on a Maleimide Scaffold

“…Furthermore, kinase inhibitors affect the protein conformation and can have effects beyond inhibition of catalytic activity, and given the importance of interactions of STK10 and SLK for various aspects of cell polarity/shape/migration as well as the additional known substrates of SLK/STK10 such as PLK1, the cellular effects of chemical inhibition of SLK/STK10 cannot be predicted with certainty. Nevertheless, the observations that SLK is essential for breast cancer cell motility, increased SLK expression is associated with increased prostate cancer cell migration, and decreased SLK expression is associated with decreased glomerular epithelial cell migration and decreased fibroblast migration suggested that chemical inhibition would be likely to decrease cell migration. The previous observation that erlotinib, which potently inhibits both SLK and STK10 among many other targets, also decreased glomerular epithelial cell migration further suggested that specific inhibition of SLK/STK10 might decrease cell migration.…”

“…Nevertheless, the observations that SLK is essential for breast cancer cell Table 7. continued motility, 21 increased SLK expression is associated with increased prostate cancer cell migration, 22 and decreased SLK expression is associated with decreased glomerular epithelial cell migration 23 and decreased fibroblast migration 24 suggested that chemical inhibition would be likely to decrease cell migration. The previous observation that erlotinib, which potently inhibits both SLK and STK10 among many other targets, also decreased glomerular epithelial cell migration 23 further suggested that specific inhibition of SLK/STK10 might decrease cell migration.…”

“…1 H NMR (400 MHz, DMSO-d 6 ) δ 10.77 (s, 1H), 9.40 (s, 1H), 7.54−7.45 (m, 2H), 7.40 (t, J = 7.5 Hz, 1H), 7.21 (d, J = 7.5 Hz, 1H), 6.77 (d, J = 8.7 Hz, 2H), 6.70 (d, J = 8.7 Hz, 2H), 2.30 (s, 3H). 13 (22). Compound 22 was isolated as a yellow solid in 41% yield.…”

Unravelling the Role of Kinases That Underpin Androgen Signalling in Prostate Cancer

“…AMPKα also phosphorylates p21 Activated Kinase 2 (PAK2) at Ser20 to activate it [118]. PAK2 is repressed by AR signalling, but its level increases during ADT and has been identified as a 'hub' protein for metastasis development [119,120], indicating an oncogenic role for AMPKα in PCa. Knockdown of CAMKK2 reduces transitioning of cells from G1 to S phase of the cell cycle, as CAMKK2 is required for AR-mediated proliferation [121].…”

Emerging Proteins in CRPC: Functional Roles and Clinical Implications

“…To identify the mechanism correlated with more distant metastasis, kinases differentially expressed between the CRPC cell lines PC-3 and PC-3M, which was a metastasis-derived variant of PC-3 cells, were analyzed by MS-based comparative phosphoproteome strategy (95). In this study, 151 phosphoproteins differently expressed between the CRPC cell lines PC-3 and PC-3M were identified (95). Seven motifs, -SP-, -SxxE-, -PxS-, -PxSP-, -SxxK-, -SPxK-, and -SxxxxxP-, were discovered to express a higher level in PC-3M cells compared to PC-3 cells (95).…”