No abstract

Splicing alterations are common in diseases such as cancer, where mutations in splicing factor genes are frequently responsible for aberrant splicing. Here we present an alternative mechanism for splicing regulation in T-cell acute lymphoblastic leukemia (T-ALL) that involves posttranslational stabilization of the splicing machinery via deubiquitination. We demonstrate there are extensive exon skipping changes in disease, affecting proteasomal subunits, cell-cycle regulators, and the RNA machinery. We present that the serine/arginine-rich splicing factors (SRSF), controlling exon skipping, are critical for leukemia cell survival. The ubiquitin-specific peptidase 7 (USP7) regulates SRSF6 protein levels via active deubiquitination, and USP7 inhibition alters the exon skipping pattern and blocks T-ALL growth. The splicing inhibitor H3B-8800 affects splicing of proteasomal transcripts and proteasome activity and acts synergistically with proteasome inhibitors in inhibiting T-ALL growth. Our study provides the proof-of-principle for regulation of splicing factors via deubiquitination and suggests new therapeutic modalities in T-ALL. SignifiCAnCE: Our study provides a new proof-of-principle for posttranslational regulation of splicing factors independently of mutations in aggressive T-cell leukemia. It further suggests a new drug combination of splicing and proteasomal inhibitors, a concept that might apply to other diseases with or without mutations affecting the splicing machinery.

This study was expected to reveal the regulatory effects of lncRNA UCA1 on pancreatic cancer cell progression through targeting miR-96/FOXO3. Microarray analysis was carried out on 36 cases of pancreatic cancer tissues and 16 cases of adjacent tissues among them. Expression levels of lncRNA UCA1, miR-96, and FOXO3 in pancreatic cancer tissues and cell lines were determined by qRT-PCR. Expression levels of FOXO3 protein were determined by western blot. Cell viability, cell cycle and apoptosis, cell invasion and migration were detected by CCK-8, flow cytometry, and transwell assay, respectively. The colocalization relationship between lncRNA UCA1 and miR-96 was detected by RNA FISH. Whether UCA1 could target miR-96 and whether miR-96 could target FOXO3 3'UTR were verified by dual-luciferase reporter gene assay. High expression of lncRNA UCA1 and FOXO3 and low expression of miR-96 were shown in pancreatic cancer. Inhibition of UCA1 suppressed pancreatic tumor cell proliferation, colony formation, and metastasis, while inhibition of miR-96 promoted pancreatic cancer cell progression. FOXO3 was the downstream target gene of miR-96 and showed the opposite effects. LncRNA UCA1 promoted cell proliferation, invasion, migration and inhibited cell apoptosis of pancreatic cancer through down-regulating miR-96 and up-regulating FOXO3. © 2018 IUBMB Life, 70(4):276-290, 2018.

Background and aimsSeveral studies were conducted to explore the prognostic value of platelet-to-lymphocyte ratio (PLR) in pancreatic cancer and have reported contradictory results. This study aims to summarize the prognostic role of PLR in pancreatic cancer.Materials and methodsEmbase, PubMed and Cochrane Library were completely searched. The cohort studies focusing on the prognostic role of PLR in pancreatic cancer were eligible. The overall survival (OS) and progression-free survival (PFS) were analyzed.ResultsFifteen papers containing 17 cohort studies with pancreatic cancer were identified. The results showed patients that with low PLR might have longer OS when compared to the patients with high PLR (hazard ratio=1.28, 95% CI=1.17–1.40, P<0.00001; I2=42%). Similar results were observed in the subgroup analyses of OS, which was based on the analysis model, ethnicity, sample size and cut-off value. Further analyses based on the adjusted potential confounders were conducted, including CA199, neutrophil-to-lymphocyte ratio, modified Glasgow Prognostic Score, albumin, C-reactive protein, Eastern Cooperative Oncology Group, stage, tumor size, nodal involvement, tumor differentiation, margin status, age and gender, which confirmed that low PLR was a protective factor in pancreatic cancer. In addition, low PLR was significantly associated with longer PFS when compared to high PLR in pancreatic cancer (hazard ratio=1.27, 95% CI=1.03–1.57, P=0.03; I2=33%).ConclusionIn conclusion, it was found that high PLR is an unfavorable predictor of OS and PFS in patients with pancreatic cancer, and PLR is a promising prognostic biomarker for pancreatic cancer.

By investigating the migration and invasion ability in pancreatic cancer, this study probed into the lncRNA MALAT1 molecular mechanism on Hippo-YAP signaling. The expression of lncRNA MALAT1 in PC tissues and cells was detected by qRT-PCR and Western blot. The effect of si-MALAT1 on proliferation was determined by CCK-8 assay. Cell apoptosis, migration, and invasion were respectively detected by flow cytometry assay, wound healing assay, and transwell assay. Western blot and immunohistochemistry were successively used for detecting LATS1 and YAP1 expression in pancreatic cancer tissues. The microarray analysis determined that lncRNA MALAT1 in pancreatic cancer was highly expressed. LncRNA MALAT1 presented an extremely high expression level in pancreatic cancer tissues and cells. After transfected with si-MALAT1, the proliferation of AsPC-1 cells decreased, induce apoptosis of AsPC-1 cells, and migration and invasion ability were reduced. The tendency of LATS1 expression level was down-regulated and YAP1 show the opposite trend in the Hippo-YAP signaling. The in vivo assay was found that the tumor to be small in size and volume, and the expression of Ki-67 was decreased. High expression of lncRNA MALAT1 in PC disorder the proliferation, apoptosis, and migration and invasion ability via influence Hippo-YAP signaling pathway.

The incidence of oral tumors in patients who never used mutagenic agents such as tobacco is increasing. In an effort to better understand these tumors we studied microRNA (miRNA) expression in tumor epithelium of never tobacco users, tumor epithelium of ever tobacco users, and nonpathological control oral epithelium. A comparison of levels among 372 miRNAs in 12 never tobacco users with oral squamous cell carcinoma (OSCC) versus 10 healthy controls was made using the reverse transcription quantitative polymerase chain reaction. A similar analysis was done with 8 ever tobacco users with OSCC. These comparisons revealed miR-10b-5p, miR-196a-5p, and miR-31-5p as enriched in the tumor epithelium in OSCC of both never and ever tobacco users. Examination of The Cancer Genome Atlas (TCGA) project miRNA data on 305 OSCCs and 30 controls revealed 100% of those miRNAs enriched in never smoker OSCCs in this patient group were also enriched in ever smoker OSCCs. Nonsupervised clustering of TCGA OSCCs was suggestive of two or four subgroups of tumors based on miRNA levels with limited evidence for differences in tobacco exposure among the groups. Results from both patient groups together stress the importance of miR196a-5p in OSCC malignancy in both never and ever smokers, and emphasize the overall similarity of miRNA expression in OSCCs in these two risk groups. It implies that there may be great similarity in etiology of OSCC in never and ever smokers and that classifying OSCC based on tobacco exposure may not be helpful in the clinic.

The association between single-nucleotide polymorphisms (SNPs) of the CYP1B1 gene and lung cancer risk is still ambiguous. In this meta analysis, we assessed 10 case-control studies included 7,067 cases and 9,374 controls of the association between CYP1B1 SNPs of Leu432Val (rs1056836, 432C>G), Asn453Ser (rs1800440, 453A>G), Ala119Ser (rs1056827, 119G>T), Arg48Gly (rs10012, 48C>G) and the risk of lung cancer. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of association between the polymorphism and lung cancer risk under codominant model, dominant model and additive model respectively. Although there were limitations, this meta analysis indicated that individuals with 432GG genotype had a 39.7% higher risk of having lung cancer than those with the 432CC genotype, and individuals with the 432G allele had a 26.3% increased risk as well. An increased risk of lung cancer of 2.13 fold was observed in individuals with 119TT genotype. For Arg48Gly, individuals with 48GG genotype had a significantly increased risk of lung cancer compared with individuals with 48CC (OR 3.859; 95% CI 2.536-5.87). Elevated risk of lung cancer were observed in dominant model (OR 2.115; 95% CI 1.653-2.705) as well. The risk of lung cancer was elevated as the frequency of G allele increased in additive model (P = 0.000). For individuals with the polymorphism at codon 453, no evidence of such association was observed. Furthermore, a possible association between the CYP1B1 polymorphism at codon 432 and the lung cancer could be detected in individuals of Caucasian origin, while a negative association was suggested in Asians and African-Americans. An increased lung cancer risk was also found in women with polymorphism at codon 453. These results are supportive for the hypothesis that the CYP1B1 432GG, 119TT and 48GG genotypes are low-penetrance risk factors for developing lung cancer, and further studies are needed to validate these associations.

Long non-coding RNAs (lncRNAs) have been shown to play a significant role in the progression of many cancers, including pancreatic cancer (PC). However, the biological function and regulatory mechanisms of lncRNAs in PC remains largely unclear. The aim of this study was to identify and evaluate the potential functions of lncRNAs in PC and reveal the underlying mechanisms of their effects. Screening of published microarray data (GEO accession Nos. GSE16515 and GSE32688), revealed lncRNA AFAP1-AS1 to be one of the most upregulated lncRNAs in PC tissues. High expression of AFAP1-AS1 was correlated with advanced stages, tumor size and lymph node metastasis, as well as with poorer overall survival in patients with PC. Functionally, knockdown of AFAP1-AS1 by transfection with siRNA inhibited the proliferative and invasive capacities of PaCa-2 and SW1990 PC cells, promoted apoptosis of PC cells in vitro, and impaired in-vivo tumorigenicity. In particular, it was hypothesized that AFAP1-AS1 may act as a competitive endogenous RNA (ceRNA), effectively becoming a sink for miR-133a whose expression was found to be downregulated in PC tissues and cell lines, and which was negatively correlated with the expression of AFAP1-AS1. We also found that the IGF1R oncogene which is an important regulator of MEK/ERK signaling pathway, was positively regulated by AFAP1-AS1 through ameliorating miR-133a-mediated IGF1R repression in PC tissues. Moreover, we demonstrated that knockdown of IGF1R by transfection with si-IGF1R suppressed cell proliferation, invasion and migration of PaCa-2 and SW1990 PC cells, suggesting that IGF1R may function as an oncogene in PC cells. Further investigations revealed that miR-133a reversed the biological effects of AFAP1-AS1 on PC cells. Collectively, the findings provide new evidence that AFAP1-AS1 could regulate the progression of pancreatic cancer by acting as a ceRNA, and suggest it has potential for use as both a biomarker for the early detection PC and for the development of individualized therapies for PC.