Dysregulation of the splicing machinery is directly associated to aggressiveness of prostate cancer

Abstract

Background: Dysregulation of splicing variants (SVs) expression has recently emerged as a novel cancer hallmark. Although the generation of aberrant SVs (e.g. AR-v7/sst5TMD4/etc.) is associated to prostate-cancer (PCa) aggressiveness and/or castration-resistant PCa (CRPC) development, whether the molecular reason behind such phenomena might be linked to a dysregulation of the cellular machinery responsible for the splicing process [spliceosome-components (SCs) and splicing-factors (SFs)] has not been yet explored. Methods: Expression levels of 43 key SCs and SFs were measured in two cohorts of PCa-samples: 1) Clinicallylocalized formalin-fixed paraffin-embedded PCa-samples (n = 84), and 2) highly-aggressive freshly-obtained PCa-samples (n = 42). Findings: A profound dysregulation in the expression of multiple components of the splicing machinery (i.e. 7 SCs/19 SFs) were found in PCa compared to their non-tumor adjacent-regions. Notably, overexpression of SNRNP200, SRSF3 and SRRM1 (mRNA and/or protein) were associated with relevant clinical (e.g. Gleason score, T-Stage, metastasis, biochemical recurrence, etc.) and molecular (e.g. AR-v7 expression) parameters of aggressiveness in PCa-samples. Functional (cell-proliferation/migration) and mechanistic [gene-expression (qPCR) and protein-levels (western-blot)] assays were performed in normal prostate cells (PNT2) and PCa-cells (LNCaP/22Rv1/PC-3/ DU145 cell-lines) in response to SNRNP200, SRSF3 and/or SRRM1 silencing (using specific siRNAs) revealed an overall decrease in proliferation/migration-rate in PCa-cells through the modulation of key oncogenic SVs expression levels (e.g. AR-v7/PKM2/XBP1s) and alteration of oncogenic signaling pathways (e.g. p-AKT/p-JNK). Interpretation: These results demonstrate that the spliceosome is drastically altered in PCa wherein SNRNP200, SRSF3 and SRRM1 could represent attractive novel diagnostic/prognostic and therapeutic targets for PCa and CRPC.

SWATH-MS Based Proteomic Profiling of Prostate Cancer Cells Reveals Adaptive Molecular Mechanisms in Response to Anti-Androgen Therapy

“…This includes the dysregulation of spliceosome components, such as HNRNPs, YBXs, SRSFs, DDXs and SNRNPs, that act as proto-oncogenic splicing regulators involved in the adaptive transcriptional programming of hormone-related cancers, such as breast and PCa [ 34 , 35 , 36 , 37 , 38 ]. HNRNPU and HNRNPK are two splicing factors involved in regulating AR and AR-v7 expression by post-transcriptional mechanisms and it has been previously found that BIC treatment alters AR/HNRNPK interaction and AR activation [ 35 , 39 , 40 ]. Proteins involved in ribosome biogenesis: DKC1 and ribosomal components: RPL19/29, RPS19/20 have been previously reported for their dysregulation and malignant potential in advanced PCa phenotypes [ 41 , 42 ].…”

“…Proteins involved in ribosome biogenesis: DKC1 and ribosomal components: RPL19/29, RPS19/20 have been previously reported for their dysregulation and malignant potential in advanced PCa phenotypes [ 41 , 42 ]. Splicing factor: SRRM1 that is involved in the RNA transport pathway has been recently described for its association with PCa proliferation/migration-rate via modulating AR-v7 levels [ 39 ]. ER signal sequence receptor subunit: SSR3 that regulates protein entry into ER plays a major role in protein processing in ER and its dysregulation has been found associated with tumor growth in PCa [ 40 , 43 , 44 ].…”

Unleashing the Diagnostic, Prognostic and Therapeutic Potential of the Neuronostatin/GPR107 System in Prostate Cancer

“…Details regarding the development, validation, and application of the RT-qPCR to measure expression levels of the transcripts of interest have been previously reported by our laboratory [32][33][34][35]. Specific and validated primers set used to measure the expression levels of genes of interest in this study (absolute mRNA copy number/50 ng of sample) are described in Table S1.…”

The role of the androgen receptor as a driver and mitigator of cellular stress

“…ATF6 inhibition (Light blue): ceapins were found to upregulate lipid droplet formation (Gallagher & Walter 2016), while melatonin was shown to block ATF6 as well as decreasing ATP production impacting metabolism (Hevia et al 2017). These investigations are supported by ongoing studies pinpointing the value of targeting UPR activity as therapeutic interventions in PCa such as targeting the splicing machinery affecting XBP1 signalling (Jiménez-Vacas et al 2020).…”