Long noncoding RNA PTPRG-AS1 acts as a microRNA-194-3p sponge to regulate radiosensitivity and metastasis of nasopharyngeal carcinoma cells via PRC1

Protein regulator of cytokinesis 1 (PRC1) has been reported in correlation with various malignancies. Functionality of PRC1 in nasopharyngeal carcinoma (NPC) was investigated, in perspective of long noncoding RNA (lncRNA) regulatory circuitry. Aberrant expressed messenger RNA and lncRNA were screened out from the Gene Expression Omnibus microarray database. NPC cell line CNE-2 was adopted for in vitro study and transfected with mimic or short hairpin RNA of miR-194-3p and PTPRG-AS1. The radioactive sensitivity, cell viability, migration, invasion, and apoptosis were detected. PTPRG-AS1 and PRC1 were upregulated in NPC, whereas miR-194-3p was downregulated. PTPRG-AS1 was found to specifically bind to miR-194-3p as a competing endogenous RNA and miR-194-3p targets and negatively regulates PRC1. Overexpressed miR-194-3p or silenced PTPRG-AS1 resulted in enhanced sensitivity to radiotherapy and cell apoptosis along with suppressed cell migration, invasion and proliferation in NPC. Furthermore, impaired tumor formation was also caused by miR-194-3p overexpression or PTPRG-AS1 suppression through xenograft tumor in nude mice. In our study, PTPRG-AS1/miR-194-3p/PRC1 regulatory circuitry was revealed in NPC, the mechanism of which can be of clinical significance for treatment of NPC.     

Transcriptional landscape of alternative splicing during peripheral nerve injury

Alternative splicing (AS) regulates a variety of biological activities in numerous tissues and organs, including the nervous system. However, the existence and specific roles of AS events during peripheral nerve repair and regeneration remain largely undetermined. In the current study, by mapping splice-crossing sequence reads, we identified AS events and relevant spliced genes in rat sciatic nerve stumps following sciatic nerve crush. AS-related genes at 1, 4, 7, and 14 days post nerve crush were compared with those at 0 day to discover alternatively spliced genes induced by sciatic nerve crush. These injury-induced alternatively spliced genes were then categorized to diseases and biological functions, genetic networks, and canonical signaling pathways. Bioinformatic analysis indicated that these alternatively spliced genes were mainly correlated to immune response, cellular growth, and cellular function maintenance. Our study elucidated AS events following peripheral nerve injury and might help deepen our understanding of the molecular mechanisms underlying peripheral nerve regeneration.     

Clinicopathological and prognostic value of lncRNA PANDAR expression in solid tumors: Evidence from a systematic review and meta-analysis

PANDAR (promoter of CDKN1A antisense DNA damage activated RNA) has been shown to be aberrantly expressed in many types of cancer. Considering conflicting data, the current study was aimed to assess its potential role as a prognostic marker in malignant tumors. A comprehensive literature search of PubMed, Medline, and Web of Science was performed to identify all eligible studies describing the use of PANDAR as a prognostic factor for different types of cancer. Data related to overall survival (OS) and clinicopathologic features were collected and analyzed. The pooled hazard ratio (HR) and odds radio (OR) with a 95% confidence interval (CI) were used to estimate associations. Ten original studies containing 1,231 patients were included. The results showed that in patients with cancer, high PANDAR expression is correlated with lymph node metastasis (LNM; OR = 2.57; 95% CI, 1.76–3.81; p < 0.001), tumor stage (OR = 2.90; 95% CI, 1.25–6.75; p = 0.013), and tumor size (OR = 1.79; 95% CI, 1.11–2.91; p = 0.018). However, sensitivity analysis further demonstrated a significant association between high PANDAR expression and OS, both in multivariate and univariate analysis models (pooled HR 2.01; 95% CI, 1.17–3.44 and pooled HR 2.62; 95% CI, 1.98–3.47, respectively), after omitting one study. These results suggested that PANDAR expression might be indicative of advanced disease and poor prognosis in patients with cancer. Further studies are necessary to determine the value of this risk stratification biomarker in clinical management of patients with cancer.     

A novel LncRNA-based prognostic score reveals TP53-dependent subtype of lung adenocarcinoma with poor survival

The prognostic signatures play an essential role in the era of personalised therapy for cancer patients including lung adenocarcinoma (LUAD). Long noncoding RNA (LncRNA), a relatively novel class of RNA, has shown to play a crucial role in all the areas of cancer biology. Here, we developed and validated a robust LncRNA-based prognostic signature for LUAD patients using three different cohorts. In the discovery cohort, four LncRNAs were identified with 10% false discovery rate and a hazard ratio of >10 using univariate Cox regression analysis. A risk score, generated from the four LncRNAs’ expression, was found to be a significant predictor of survival in the discovery and validation cohort (p = 9.97 × 10 ⁻⁸ and 1.41 × 10 ⁻³, respectively). Further optimisation of four LncRNAs signature in the validation cohort, generated a three LncRNAs prognostic score (LPS), which was found to be an independent predictor of survival in both the cohorts ( p = 1.00 × 10 ⁻⁶ and 7.27 × 10 ⁻⁴, respectively). The LPS also significantly divided survival in clinically important subsets, including Stage I ( p = 9.00 × 10 ⁻⁴ and 4.40 × 10 ⁻², respectively), KRAS wild-type (WT), KRAS mutant ( p = 4.00 × 10 ⁻³ and 4.30 × 10 ⁻², respectively) and EGFR WT ( p = 2.00 × 10 ⁻⁴). In multivariate analysis LPS outperformed, eight previous prognosticators. Further, individual members of LPS showed a significant correlation with survival in microarray data sets. Mutation analysis showed that high-LPS patients have a higher mutation rate and inactivation of the TP53 pathway. In summary, we identified and validated a novel LncRNA signature LPS for LUAD.     

病毒功能性受体的筛选新策略及其应用

病毒通过与靶细胞表面的特异性受体结合,进而吸附、入侵靶细胞,劫持细胞的复制机器完成自身的复制周期。细胞受体作为病毒入侵宿主的门户,细胞受体的结构与功能及其介导病毒入侵的机制一直是病毒学研究的热点之一。对细胞受体的研究有助于了解病毒的致病机制并为病毒性疾病的防控提供科学依据。近年来,利用功能缺失性基因组学筛选病毒功能性受体的进展极大地拓展了人类对病毒入侵机制的认识和理解。目前,应用较为广泛的病毒功能性受体筛选策略包括RNA干扰技术、利用单倍体细胞系随机插入逆转录病毒致突变技术以及基于CRISPR/Cas9系统的新型编辑技术。本文系统介绍并比较了这三种病毒功能性受体筛选新策略,同时对其应用及优缺点进行了归纳总结,可为相关研究者提供一定的参考。     

Contribution of NDH-dependent cyclic electron transport around photosystem I to the generation of proton motive force in the weak mutant allele of pgr5

In angiosperms, cyclic electron transport (CET) around photosystem I (PSI) consists of two pathways, depending on PGR5/PGRL1 proteins and the chloroplast NDH complex. In single mutants defective in chloroplast NDH, photosynthetic electron transport is only slightly affected at low light intensity, but in double mutants impaired in both CET pathways photosynthesis and plant growth are severely affected. The question is whether this strong mutant phenotype observed in double mutants can be simply explained by the additive effect of defects in both CET pathways. In this study, we used the weak mutant allele of pgr5-2 for the background of double mutants to avoid possible problems caused by the secondary effects due to the strong mutant phenotype. In two double mutants, crr2-2 pgr5-2 and ndhs-1 pgr5-2, the plant growth was unaffected and linear electron transport was only slightly affected. However, NPQ induction was more severely impaired in the double mutants than in the pgr5-2 single mutant. A similar trend was observed in the size of the proton motive force. Despite the slight reduction in photosystem II parameters, PSI parameters were severely affected in the pgr5-2 single mutant, the phenotype that was further enhanced by adding the NDH defects. Despite the lack of ?pH-dependent regulation at the cytochrome b₆f complex (donor-side regulation of PSI), the plastoquinone pool was more reduced in the double mutants than in the pgr5-2 single mutants. This phenotype suggests that both PGR5/PGRL1- and NDH-dependent CET contribute to supply sufficient acceptors from PSI by balancing the ATP/NADPH production ratio.     

Circular RNA circMTO1 suppresses bladder cancer metastasis by sponging miR-221 and inhibiting epithelial-to-mesenchymal transition

Bladder cancer remains a leading cause of cancer-related death because of its distant metastasis and high recurrence rates. Deregulation of circular RNAs (circRNAs) can act either as tumor suppressors or oncogenes to control cell proliferation, migration, and metastasis. The role of circMTO1 in bladder cancer remain unknown. In this study, we investigated whether circMTO1 could use as a biomarker and therapeutic target for bladder cancer treatment. We first demonstrated that circMTO1 was an important circRNA frequently downregulated in bladder cancer tissue, and lower circMTO1 levels were positively correlated with bladder cancer patients' metastasis and poorer survival. Ectopic expression of circMTO1 in bladder cancer cells inhibited cell's epithelial-to-mesenchymal transition (EMT) and metastasis. In addition, we also revealed that circMTO1 was able to sponge miR-221 and overexpression of circMTO1 negatively regulated the E-cadherin/N-cadherin pathway to inhibit bladder cancer cells' EMT by competing for miR-221. In conclusion, our findings provide comprehensive evidences that circMTO1 is a prognostic biomarker in bladder cancer and suggest that circMTO1 may function as a novel therapeutic target in human bladder cancer.     

CircPUM1 promotes the malignant behavior of lung adenocarcinoma by regulating miR-326

CircRNAs are reported to be implicated in the development of lung cancer. This study focused on assessing the expression, functions and molecular mechanism of circPUM1 in lung adenocarcinoma. Here, it showed that circPUM1 is significantly upregulated in both lung adenocarcinoma cell lines and tissues. Furthermore, silencing of circPUM1 impaired the proliferation, migration and invasion ability, and increased apoptosis in A549?cells. Nevertheless, overexpression of circPUM1 in SPC-A1 cells has the opposite effect. Silencing of circPUM1 inhibits the tumorigenesis in nude mice. Mechanistically, circPUM1 could sponge miR-326 and promote the expression of its downstream proteins Cyclin D1 and Bcl-2. In summary, this present study revealed that circPUM1 functions as an oncogene to promote the tumorigenesis of lung adenocarcinoma through circPUM1/miR-326/Cyclin D1 and Bcl-2 axis. This indicates that circPUM1 may act as a potential therapeutic target for lung adenocarcinoma.