Potential Antileukemia Effect and Structural Analyses of SRPK Inhibition by N-(2-(Piperidin-1-yl)-5-(Trifluoromethyl)Phenyl)Isonicotinamide (SRPIN340)

Abstract

Dysregulation of pre-mRNA splicing machinery activity has been related to the biogenesis of several diseases. The serine/arginine-rich protein kinase family (SRPKs) plays a critical role in regulating pre-mRNA splicing events through the extensive phosphorylation of splicing factors from the family of serine/arginine-rich proteins (SR proteins). Previous investigations have described the overexpression of SRPK1 and SRPK2 in leukemia and other cancer types, suggesting that they would be useful targets for developing novel antitumor strategies. Herein, we evaluated the effect of selective pharmacological SRPK inhibition by N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340) on the viability of lymphoid and myeloid leukemia cell lines. Along with significant cytotoxic activity, the effect of treatments in regulating the phosphorylation of the SR protein family and in altering the expression of MAP2K1, MAP2K2, VEGF and FAS genes were also assessed. Furthermore, we found that pharmacological inhibition of SRPKs can trigger early and late events of apoptosis. Finally, intrinsic tryptophan fluorescence emission, molecular docking and molecular dynamics were analyzed to gain structural information on the SRPK/SRPIN340 complex. These data suggest that SRPK pharmacological inhibition should be considered as an alternative therapeutic strategy for fighting leukemias. Moreover, the obtained SRPK-ligand interaction data provide useful structural information to guide further medicinal chemistry efforts towards the development of novel drug candidates.

SRPKIN-1: A Covalent SRPK1/2 Inhibitor that Potently Converts VEGF from Pro-angiogenic to Anti-angiogenic Isoform

“…Three chemical scaffolds have been described with inhibitory activities against SRPK1 (Batson et al, 2017; Morooka et al, 2015; Fukuhara et al, 2006; Siqueira et al, 2015; Székelyhidi et al, 2005; Gammons et al, 2013), and, among them, SPHINX31 was recently derived from SPHINX and reported to have much improved potency (Batson et al, 2017). Although high-throughput screening has been commonly used to generate lead compounds in kinase inhibitor projects, we chose to query existing kinase inhibitor libraries and known FDA-approved drugs for their potential abilities to target SRPK1, an approach that offers advantages in expediting structure-activity relationship (SAR) studies and optimizing pharmacological properties.…”

Enhancer of rudimentary homologue interacts with scaffold attachment factor B at the nuclear matrix to regulate SR protein phosphorylation

“…SR protein kinase 1 has been shown to move into the nucleus in a cell cycle regulated manner [24,45,46] not only at the G2/M phase, but also under other signals such as osmotic changes [47] or growth factor signalling [48,49], as proposed to account for the implication of SRPK1 in tumor development. Many studies find that SRPK1 levels are mostly elevated in different types of tumors [49][50][51] and correlate with cancer progression and worse patient outcome [52,53], highlighting SRPK1 as a target for anticancer treatment [54][55][56][57]. Upon entrance into the nucleus, SRPK1 is found not only in nuclear speckles, which are accepted to be storage sites for splicing factors, but also in the nucleoplasm.…”

Redirecting SR Protein Nuclear Trafficking through an Allosteric Platform

“…Both SRPKs and CLKs are often over-expressed in various cancers emphasizing the relationship between SR protein phosphorylation and splicing as well as the potential for therapeutic intervention through kinase inhibition strategies 27,28 . Indeed, inhibition of SRPKs using the small molecule SRPIN340 induces apoptosis in leukemia cell lines and reduces the splicing of a pro-angiogenic form of VEGF 29–31 .…”