Results We found SNRPA widely expression
Results: We found SNRPA1 widely expression in many representative CRC cell lines. Knocking down expression of SNRPA1 by shRNA lentivirus inhibited the cell proliferation in vitro and impaired tumor formation from implanted CRC Necrostatin-1 transduced with SNRPA1 silencing shRNA lentivirus in nude mice. It also promoted the cell apoptosis by upregulating the caspase 3/7 activity. Additional microarray gene profiling analysis uncovered the gene interaction network of SNRPA1, special focus was placed on its association with tumor suppressor or oncogenes.
Conclusions: According to the results of gene interaction network as well as qRT-PCR verification, it revealed that SNPRA1 regulates PIK3R1, VEGFC, MKI67, CDK1 in CRC. These novel findings identified new roles played by SNRPA1 in the progression of CRC and it may become a potential therapeutic target in the treatment of CRC.
1. Introduction CRC arises from one or a combination of chromosomal instability
(CIN), CpG island methylator phenotype (CIMP), and microsatellite Colorectal cancer (CRC), the fourth most common cancer worldwide instability (MSI) . Genetic instability is usually caused by aneuploidy (˜1,360,000 cases per year) and the second commonest cause of cancer- and loss of heterozygosity (LOH). Mutation in the tumor suppressor or related deaths in the Western world, results in around 650,000 deaths cell cycle genes may also led to cellular transformation. Similarly, worldwide per year . The life-time incidence of CRC is about 5% and epigenetic modifications such as DNA methylation, histone modifica- progressively increases after the age of 50. In 2018, the GLOBOCAN tion, and/or genetic alterations resulting in impaired cellular pathways online analysis tool has predicted 606,840 new cases for Asia. CRC may lead to microsatellite instability and mutator phenotype. Non- initially develops from benign and frequently occurring adenomas: coding RNAs, more importantly microRNAs and long non-coding RNAs approximately 50% of the Western population has an adenoma by age have also been implicated at various CRC stages. According to Fearon 70. However, it takes several years before a full-blown malignant col- , the classical CIN pathway begins with the acquisition of mutations orectal carcinoma developed. During this period, a precise series of in the adenomatous polyposis coli (APC), followed by the mutational molecular events happened to drive the progression of the disease, activation of oncogene KRAS and the inactivation of the tumor sup- which required the accumulation of mutations in oncogenes and tumor pressor gene, TP53. Aneuploidy and LOH are the major players in CIN suppressor genes in these initially benign lesions [1–3]. tumors. The CIMP pathway is characterized by promoter
hypermethylation of various tumor suppressor genes such as MGMT and MLH1. The MSI pathway involves the inactivation of genetic al-terations in short repeated sequences. Moreover, the three mechanisms often overlap in CRC. Understanding of the specific mechanisms of tumorigenesis and the underlying genetic and epigenetic traits is cri-tical in comprehending the disease phenotype.
Around 70% of sporadic colorectal tumors show biallelic inactiva-tion of the APC gene, a high percentage of remaining tumors show activating mutations in beta-catenin or axin, which are components of the Wnt signaling pathway [5,6]. The transactivation of beta-catenin/ TCF target genes represents a primary transforming event in CRC. In various models, activating mutations in this pathway eﬀectively initiate tumorogenesis in the intestine in a process similar to those found in humans. SNPRA1 (small nuclear ribonucleoprotein polypeptide A), a spliceosome component responsible for processing of pre-mRNA into mRNA, has been found essential for male fertility . In another study , SNRPA1, together with TCF7L2, a transcriptional factor of the Wnt signaling pathway, were found to bind to the insertion allele of rs386772267, a genetic insertion which is associated with increased risk of pancreatic cancer and results in reduced DIS3 expression, a subunit of the nuclear RNA exosome complex that mediates RNA pro-cessing and decay. SNRPA1 has also emerged as a prognostic marker in renal cancer (unfavourable), live cancer (unfavourable), and ovarian cancer (favourable). A comprehensive comparison of gene expression profiling in colon tumors from independent mouse models and human CRCs vs normal samples also identified a large cluster of genes highly enriched for functional association to the control of cell cycle pro-gression, proliferation, and migration, which include SNRPA1. In the previous study (unpublished data), we found many diﬀerential genes highly expressed in CRC by transcriptome sequencing, and through further high content screening, we found that the target gene SNRPA1 may play essential roles in CRC. Other than those available aspects, the role of SNRPA1 and its associating regulatory network in CRC is still at large. Therefore, in this work we aim to investigate the additional role of SNRPA1 in CRC, and our results indicated that SNRPA1 is widely expressed in CRC cancer cells, knocking down of SNRPA1 promoted the apoptosis of and inhibited the cell proliferation of CRC cells, further microarray gene expression profiling revealed that SNRPA1 played its role via regulating PIK3R1, VEGFC, MKI67, CDK1 and other genes in CRC. Those results uncovered novel role of SNRPA1 in CRC and it may become a new therapeutic target in the treatment of CRC.