SRPK1 facilitates tumor cell growth via modulating the small nucleolar RNA expression in gastric cancer

Integrative profiling analysis reveals prognostic significance, molecular characteristics, and tumor immunity of angiogenesis-related genes in soft tissue sarcoma

Background

Soft tissue sarcoma (STS) is a class of malignant tumors originating from mesenchymal stroma with a poor prognosis. Accumulating evidence has proved that angiogenesis is an essential hallmark of tumors. Nevertheless, there is a paucity of comprehensive research exploring the association of angiogenesis-related genes (ARGs) with STS.

Methods

The ARGs were extracted from previous literature, and the differentially expressed ARGs were screened for subsequent analysis. Next, the least absolute shrinkage and selection operator (LASSO) and Cox regression analyses were conducted to establish the angiogenesis-related signature (ARSig). The predictive performance of the novel ARSig was confirmed using internal and external validation, subgroup survival, and independent analysis. Additionally, the association of the ARSig with the tumor immune microenvironment, tumor mutational burden (TMB), and therapeutic response in STS were further investigated. Notably, we finally conducted in vitro experiments to verify the findings from the bioinformatics analysis.

Results

A novel ARSig is successfully constructed and validated. The STS with a lower ARSig risk score in the training cohort has an improved prognosis. Also, consistent results were observed in the internal and external cohorts. The receiver operating characteristic (ROC) curve, subgroup survival, and independent analysis further indicate that the novel ARSig is a promising independent prognostic predictor for STS. Furthermore, it is proved that the novel ARSig is relevant to the immune landscape, TMB, immunotherapy, and chemotherapy sensitivity in STS. Encouragingly, we also validate that the signature ARGs are significantly dysregulated in STS, and ARDB2 and SRPK1 are closely connected with the malignant progress of STS cells.

Conclusion

In sum, we construct a novel ARSig for STS, which could act as a promising prognostic factor for STS and give a strategy for future clinical decisions, immune landscape, and personalized treatment of STS.

Underexplored reciprocity between genome-wide methylation status and long non-coding RNA expression reflected in breast cancer research: potential impacts for the disease management in the framework of 3P medicine

Breast cancer (BC) is the most common female malignancy reaching a pandemic scale worldwide. A comprehensive interplay between genetic alterations and shifted epigenetic regions synergistically leads to disease development and progression into metastatic BC. DNA and histones methylations, as the most studied epigenetic modifications, represent frequent and early events in the process of carcinogenesis. To this end, long non-coding RNAs (lncRNAs) are recognized as potent epigenetic modulators in pathomechanisms of BC by contributing to the regulation of DNA, RNA, and histones' methylation. In turn, the methylation status of DNA, RNA, and histones can affect the level of lncRNAs expression demonstrating the reciprocity of mechanisms involved. Furthermore, lncRNAs might undergo methylation in response to actual medical conditions such as tumor development and treated malignancies. The reciprocity between genome-wide methylation status and long non-coding RNA expression levels in BC remains largely unexplored. Since the bio/medical research in the area is, per evidence, strongly fragmented, the relevance of this reciprocity for BC development and progression has not yet been systematically analyzed. Contextually, the article aims at:consolidating the accumulated knowledge on both-the genome-wide methylation status and corresponding lncRNA expression patterns in BC andhighlighting the potential benefits of this consolidated multi-professional approach for advanced BC management. Based on a big data analysis and machine learning for individualized data interpretation, the proposed approach demonstrates a great potential to promote predictive diagnostics and targeted prevention in the cost-effective primary healthcare (sub-optimal health conditions and protection against the health-to-disease transition) as well as advanced treatment algorithms tailored to the individualized patient profiles in secondary BC care (effective protection against metastatic disease). Clinically relevant examples are provided, including mitochondrial health control and epigenetic regulatory mechanisms involved.

Inhibition of SRPK1, a key splicing regulator, exhibits antitumor and chemotherapeutic-sensitizing effects on extranodal NK/T-cell lymphoma cells

BACKGROUND

Increasing evidence has convincingly shown that abnormal pre-mRNA splicing is implicated in the development of most human malignancies. Serine/arginine-rich protein kinase 1 (SRPK1), a key splicing regulator, is reported to be overexpressed in leukemia and other cancer types, which suggests the therapeutic potential of targeting SRPK1.

METHODS

SRPK1 expression was measured in 41 ENKTL patients by immunohistochemistry and mRNA expression was analyzed by qRT‒PCR. We knocked down SRPK1 expression in the ENKTL cell line YT by siRNA transfection and inhibited SRPK1 using inhibitors (SPHINX31 and SRPIN340) in YT cells and peripheral blood lymphocytes (PBLs) isolated from ENKTL patients to investigate its role in cell proliferation and apoptosis. Then, RNA-seq analysis was performed to predict the potential signaling pathway by which SRPK1 inhibition induces cell death and further verified this prediction by Western blotting.

RESULTS

In the present study, we initially evaluated the clinical significance of SRPK1 in extranodal natural killer/T-cell lymphoma (ENKTL), a very aggressive subtype of non-Hodgkin lymphoma. The expression of SRPK1 in ENKLT patients was examined by immunohistochemistry and qRT‒PCR, which revealed SRPK1 overexpression in more than 60% of ENKTL specimens and its association with worse survival. Cellular experiments using the human ENKTL cell line YT and PBLs from ENKTL patients, demonstrated that inhibition of SRPK1 suppressed cell proliferation and induced apoptosis. Subsequently, we investigated the downstream targets of SRPK1 by RNA-seq analysis and found that SRPK1 inhibition induced ATF4/CHOP pathway activation and AKT1 inhibition. Furthermore, ENKTL patients presenting high SRPK1 expression showed resistance to cisplatin-based chemotherapy. The association of SRPK1 expression with cisplatin resistance was also confirmed in YT cells. SRPK1 overexpression via pLVX-SRPK1 plasmid transfection dramatically decreased the sensitivity of YT cells to cisplatin, while siRNA-mediated SRPK1 knockdown or SRPK1 inhibitor treatment significantly increased cisplatin cytotoxicity.

CONCLUSION

In summary, these results support that SRPK1 might be a useful clinical prognostic indicator and therapeutic target for ENKTL, especially for patients who relapse after cisplatin-based chemotherapies.

Dysregulation of Small Nucleolar RNAs in B-Cell Malignancies

Small nucleolar RNAs (snoRNAs) are responsible for post-transcriptional modification of ribosomal RNAs, transfer RNAs and small nuclear RNAs, and thereby have important regulatory functions in mRNA splicing and protein translation. Several studies have shown that snoRNAs are dysregulated in human cancer and may play a role in cancer initiation and progression. In this review, we focus on the role of snoRNAs in normal and malignant B-cell development. SnoRNA activity appears to be essential for normal B-cell differentiation and dysregulated expression of sno-RNAs is determined in B-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, B-cell non-Hodgkin’s lymphoma, and plasma cell neoplasms. SnoRNA expression is associated with cytogenetic/molecular subgroups and clinical outcome in patients with B-cell malignancies. Translocations involving snoRNAs have been described as well. Here, we discuss the different aspects of snoRNAs in B-cell malignancies and report on their role in oncogenic transformation, which may be useful for the development of novel diagnostic biomarkers or therapeutic targets.

Serine-Arginine Protein Kinase 1 (SRPK1): a systematic review of its multimodal role in oncogenesis

Alternative splicing is implicated in each of the hallmarks of cancer, and is mechanised by various splicing factors. Serine-Arginine Protein Kinase 1 (SRPK1) is an enzyme which moderates the activity of splicing factors rich in serine/arginine domains. Here we review SRPK1’s relationship with various cancers by performing a systematic review of all relevant published data. Elevated SRPK1 expression correlates with advanced disease stage and poor survival in many epithelial derived cancers. Numerous pre-clinical studies investigating a host of different tumour types; have found increased SRPK1 expression to be associated with proliferation, invasion, migration and apoptosis in vitro as well as tumour growth, tumourigenicity and metastasis in vivo. Aberrant SRPK1 expression is implicated in various signalling pathways associated with oncogenesis, a number of which, such as the PI3K/AKT, NF-КB and TGF-Beta pathway, are implicated in multiple different cancers. SRPK1-targeting micro RNAs have been identified in a number of studies and shown to have an important role in regulating SRPK1 activity. SRPK1 expression is also closely related to the response of various tumours to platinum-based chemotherapeutic agents. Future clinical applications will likely focus on the role of SRPK1 as a biomarker of treatment resistance and the potential role of its inhibition.

Overexpression of small nucleolar RNA SNORD1C is associated with unfavorable outcome in colorectal cancer

Colorectal cancer (CRC) is the second most incident cancer and third leading cause of cancer-related mortality worldwide. Small nucleolar RNAs (snoRNAs) are small non-coding RNAs located in the nucleoli of cells, and play key roles in multiple cancers. However, the role of serum snoRNAs in CRC remains unknown. We analyzed the expression of the snoRNA SNORD1C in the serum of patients with CRC using quantitative real-time polymerase chain reaction (qRT-PCR) (n = 122). The receiver operating characteristic (ROC) curves were estimated, and the area under the ROC curve (AUC) was calculated. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis of co-expressed genes was performed using the database for annotation, visualization, and integrated discovery (DAVID), and visualized by R language. The results showed that the expression of SNORD1C in patients with CRC (n = 122) was significantly higher than that in normal individuals (n = 50) and patients with benign colorectal disease (n = 33) (P < 0.05). The overexpression of serum SNORD1C was related to poor tissue differentiation and high carcinoembryonic antigen (CEA) levels (P < 0.05). In the ROC curve analysis, SNORD1C serum expression combined with CEA offered better predictive value for the diagnosis of CRC (AUC = 0.838) compared with SNORD1C (AUC = 0.748) or CEA (AUC = 0.715) alone. High expression of SNORD1C was found to be closely associated with prognosis and unfavorable outcomes in patient with CRC. Therefore, serum SNORD1C may be a noninvasive tumor biomarker for diagnosis of CRC.

The role of OncoSnoRNAs and Ribosomal RNA 2'-O-methylation in Cancer

Ribosomes are essential nanomachines responsible for all protein production in cells. Ribosome biogenesis and function are energy costly processes, they are tightly regulated to match cellular needs. In cancer, major pathways that control ribosome biogenesis and function are often deregulated to ensure cell survival and to accommodate the continuous proliferation of tumour cells. Ribosomal RNAs (rRNAs) are abundantly modified with 2'-O-methylation (Nm, ribomethylation) being one of the most common modifications. In eukaryotic ribosomes, ribomethylation is performed by the methyltransferase Fibrillarin guided by box C/D small nucleolar RNAs (snoRNAs). Accumulating evidences indicate that snoRNA expression and ribosome methylation profiles are altered in cancer. Here we review our current knowledge on differential snoRNA expression and rRNA 2ʹ-O methylation in the context of human malignancies, and discuss the consequences and opportunities for cancer diagnostics, prognostics, and therapeutics.

LncRNA Neat1/miR-298-5p/Srpk1 Contributes to Sevoflurane-Induced Neurotoxicity

Sevoflurane is a widely used volatile anesthetic, that can cause long-term neurotoxicity and learning and memory impairment. Long non-coding RNAs (lncRNAs) have been demonstrated to function as key mediators in neurotoxicity. This study aimed to investigate the effects of lncRNA Neat1 on sevoflurane-induced neurotoxicity. The expression of Neat1, miR-298-5p, and Srpk1 was measured by RT-qPCR. Cell viability, cell apoptosis, inflammation markers, and reactive oxygen species (ROS) generation were examined by CCK-8, TUNEL, ELISA, and the ROS kit. The interaction between miR-298-5p and Neat1 or Srpk1 was confirmed by luciferase reporter assay. In our study, it was found that sevoflurane aggravated neurotoxicity through inhibiting cell viability and enhancing cell apoptosis, neuroinflammation, and ROS generation. Neat1 was up-regulated in sevoflurane-treated HT22 cells, and Neat1 knockdown improved sevoflurane-mediated neurotoxicity. Through the exploration of the ceRNA mechanism, we found that Neat1 bound with miR-298-5p, and Srpk1 was a direct target gene of miR-298-5p. Finally, rescue assays proved that up-regulation of Srpk1 reversed the effects of Neat1 knockdown on neurotoxicity. In conclusion, our study revealed that lncRNA Neat1 facilitated sevoflurane-stimulated neurotoxicity by sponging miR-298-5p to up-regulate Srpk1. These findings might provide novel insights into the treatment of sevoflurane-induced neurotoxicity.

Can small nucleolar RNA be a novel molecular target for hepatocellular carcinoma?

BACKGROUND

Globally, hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death. Recently, many studies have demonstrated that small nucleolar RNA (snoRNA) was closely related to HCC.

OBJECTIVE

To explore whether snoRNA can be used as a molecular target for HCC.

METHODS

The PubMed, Embase, and Cochrane databases were searched for the published literatures related to snoRNA and HCC until August 12, 2019. After identification, screening, and verification, this study finally included 26 studies correlating small nucleolar RNA host gene (SNHG) and HCC, and 8 studies correlating snoRNA and HCC. Based on the collation of the relevant literature, the correlation network diagram between snoRNAs and HCC was constructed.

RESULTS

The SNHGs, such as SNHG1, SNHG6, SNHG16, and SNHG20 can play varied roles in HCC through different regulatory mechanisms. These SNHGs can promote and inhibit tumorigenesis. SNORD76 can promote the proliferation of tumor tissues and cells in vitro through different pathways. SnoU2_19 and SNORD76 can function through the same pathway. SNHG3, SNHG20, SNHG6, SNORD76, and snoRA47 can modulate epithelial-mesenchymal transition (EMT) to regulate the development of HCC cell or tissue. SNHG16, SNORD76, and SnoU2_19 can regulate the development of HCC through Wnt/β-catenin signaling pathway.

CONCLUSION

snoRNA can regulate the occurrence of HCC by modulating multiple molecular signaling pathways. Hence, snoRNA can be a potential molecular target for HCC.

Serine-Arginine Protein Kinase 1 (SRPK1) as a Prognostic Factor and Potential Therapeutic Target in Cancer: Current Evidence and Future Perspectives

Cancer, a heterogeneous disease composed of tumor cells and microenvironment, is driven by deregulated processes such as increased proliferation, invasion, metastasis, angiogenesis, and evasion of apoptosis. Alternative splicing, a mechanism led by splicing factors, is implicated in carcinogenesis by affecting any of the processes above. Accumulating evidence suggests that serine-arginine protein kinase 1 (SRPK1), an enzyme that phosphorylates splicing factors rich in serine/arginine domains, has a prognostic and potential predictive role in various cancers. Its upregulation is correlated with higher tumor staging, grading, and shorter survival. SRPK1 is also highly expressed in the premalignant changes of some cancers, showing a potential role in the early steps of carcinogenesis. Of interest, its downregulation in preclinical models has mostly been tumor-suppressive and affected diverse processes heterogeneously, depending on the oncogenic context. In addition, targeting SRPK1 has enhanced sensitivity to platinum-based chemotherapy in some cancers. Lastly, its aberrant function has been noted not only in cancer cells but also in the endothelial cells of the microenvironment. Although the aforementioned evidence seems promising, more studies are needed to reinforce the use of SRPK1 inhibitors in clinical trials.