Viral Mimicry Response Is Associated With Clinical Outcome in Pleural Mesothelioma.

Introduction: The aim of this study was to investigate endogenous retrovirus (ERV) expression and type I interferon (IFN) activation in human pleural mesothelioma (PM) and their association with clinical outcome. Methods: The expression of ERV was determined from PM cohorts and mesothelial precursor RNA sequencing data. The expression of ERV was confirmed by quantitative polymerase chain reaction (qPCR). Methylation of genomic DNA was assessed by quantitative methylation-specific PCR. DNA demethylation was induced in cells by demethylating agent 5-Aza-2'-deoxycytidine (5-Aza-CdR) treatment. To block type I IFN signaling, the cells were treated with ruxolitinib or MAVS silencing. The expression of IFN-stimulated genes (ISGs) was determined by qPCR and Western blot. Circulating ERVs were detected by qPCR. Results: Long terminal repeats (LTRs) represent the most abundant transposable elements up-regulated in PM. Within the LTR, ERVmap_1248 and LTR7Y, which are specifically enriched in PM, were further analyzed. The 5-Aza-CdR treatment increased the levels of ERVmap_1248 expression and induced ERVmap_1248 promoter demethylation in mesothelial cells. In addition, ERVmap_1248 promoter was more demethylated in the mesothelioma tissue compared with nontumor tissue. The 5-Aza-CdR treatment of the mesothelial cells also increased the levels of ISGs. Basal ISG expression was higher in the mesothelioma cells compared with the mesothelial cells, and it was significantly decreased by ruxolitinib treatment or MAVS silencing. Furthermore, ISG expression was higher in the tumor tissue with high expression levels of ERVmap_1248. High expression of ERVmap_1248 was associated with longer overall survival and BAP1 mutations. ERVmap_1248 and LTR7Y can be detected in the PM plasma. Conclusions: We provide clues for patient stratification especially for immunotherapy where best clinical responses are associated with an activated basal immune response.

Heterogeneous RNA editing and influence of ADAR2 on mesothelioma chemoresistance and the tumor microenvironment.

We previously observed increased levels of adenosine-deaminase-acting-on-dsRNA (Adar)-dependent RNA editing during mesothelioma development in mice exposed to asbestos. The aim of this study was to characterize and assess the role of ADAR-dependent RNA editing in mesothelioma. We found that tumors and mesothelioma primary cultures have higher ADAR-mediated RNA editing compared to mesothelial cells. Unsupervised clustering of editing in different genomic regions revealed heterogeneity between tumor samples as well as mesothelioma primary cultures. ADAR2 expression levels are higher in BRCA1-associated protein 1 wild-type tumors, with corresponding changes in RNA editing in transcripts and 3'UTR. ADAR2 knockdown and rescue models indicated a role in cell proliferation, altered cell cycle, increased sensitivity to antifolate treatment, and type-1 interferon signaling upregulation, leading to changes in the microenvironment in vivo. Our data indicate that RNA editing contributes to mesothelioma heterogeneity and highlights an important role of ADAR2 not only in growth regulation in mesothelioma but also in chemotherapy response, in addition to regulating inflammatory response downstream of sensing nucleic acid structures.

Double-Stranded RNA Structural Elements Holding the Key to Translational Regulation in Cancer: The Case of Editing in RNA-Binding Motif Protein 8A.

Mesothelioma is an aggressive cancer associated with asbestos exposure. RNA-binding motif protein 8a (RBM8A) mRNA editing increases in mouse tissues upon asbestos exposure. The aim of this study was to further characterize the role of RBM8A in mesothelioma and the consequences of its mRNA editing. RBM8A protein expression was higher in mesothelioma compared to mesothelial cells. Silencing RBM8A changed splicing patterns in mesothelial and mesothelioma cells but drastically reduced viability only in mesothelioma cells. In the tissues of asbestos-exposed mice, editing of Rbm8a mRNA was associated with increased protein immunoreactivity, with no change in mRNA levels. Increased adenosine deaminase acting on dsRNA (ADAR)-dependent editing of Alu elements in the RBM8A 3'UTR was observed in mesothelioma cells compared to mesothelial cells. Editing stabilized protein expression. The unedited RBM8A 3'UTR had a stronger interaction with Musashi (MSI) compared to the edited form. The silencing of MSI2 in mesothelioma or overexpression of Adar2 in mesothelial cells resulted in increased RBM8A protein levels. Therefore, ADAR-dependent editing contributes to maintaining elevated RBM8A protein levels in mesothelioma by counteracting MSI2-driven downregulation. A wider implication of this mechanism for the translational control of protein expression is suggested by the editing of similarly structured Alu elements in several other transcripts.

Endogenous retrovirus expression activates type-I interferon signaling in an experimental mouse model of mesothelioma development.

Early events in an experimental model of mesothelioma development include increased levels of editing in double-stranded RNA (dsRNA). We hypothesised that expression of endogenous retroviruses (ERV) contributes to dsRNA formation and type-I interferon signaling. ERV and interferon stimulated genes (ISGs) expression were significantly higher in tumor compared to non-tumor samples. 12 tumor specific ERV ("MesoERV1-12") were identified and verified by qPCR in mouse tissues. "MesoERV1-12" expression was lower in mouse embryonic fibroblasts (MEF) compared to mesothelioma cells. "MesoERV1-12" levels were significantly increased by demethylating agent 5-Aza-2'-deoxycytidine treatment and were accompanied by increased levels of dsRNA and ISGs. Basal ISGs expression was higher in mesothelioma cells compared to MEF and was significantly decreased by JAK inhibitor Ruxolitinib, by blocking Ifnar1 and by silencing Mavs. "MesoERV7" promoter was demethylated in asbestos-exposed compared to sham mice tissue as well as in mesothelioma cells and MEF upon 5-Aza-CdR treatment. These observations uncover novel aspects of asbestos-induced mesothelioma whereby ERV expression increases due to promoter demethylation and is paralleled by increased levels of dsRNA and activation of type-I IFN signaling. These features are important for early diagnosis and therapy.

Laparoscopic-Assisted Longitudinal Incision and Transverse Anastomosis: A Novel Surgical Approach for Treatment of Esophageal Stenosis Caused by Tracheobronchial Remnants.

Purpose: To review the treatment of lower congenital esophageal stenosis caused by tracheobronchial remnants (TBR) and to introduce a novel technical approach through laparoscopic surgery. Methods: Patients with TBR who underwent surgery in our single-center from January 2016 to December 2019 were enrolled. Resection of cartilage with stenotic esophageal segment and end-to-end anastomosis was the traditional surgery. Since 2018, longitudinal incision with partial resection of cartilage loop in the anterior esophageal wall and the transverse suture was conducted endoscopically. We reviewed the treatment, followed-up with these patients, and discussed the new procedure's preponderance. Main Results: Thirteen patients underwent surgery and were followed-up for 0.5-45 months (M = 13) after surgery. Twelve patients showed good physical development with a regular diet. One patient, who was 2 weeks after the surgery, was fed by a soft diet and regularly followed-up at our clinic. In 13 cases, five patients underwent traditional laparotomy with pyloroplasty. Two patients who went through anastomotic leakage were cured by drainage and conservative treatments. Anastomotic stricture that occurred in two cases was improved by one-time of dilation. The administration time of parenteral nutrition (PN) was 9.0 ± 1.4 days. The length of hospitalization was 36.6 ± 5.2 days. Eight cases underwent the new surgical approach through laparoscopy or thoracoscopy. Pyloroplasty was avoided since the vagal close to the posterior wall of the esophagus was protected. Gastric motility disorder did not occur as expected. No leakage occurred postoperatively. The anastomotic stricture was found in six cases and improved after one to five times of dilations. The length of hospitalization dropped to 18.6 ± 6.9 days significantly (P < .001). Conclusions: Longitudinal incision and transverse anastomosis of the anterior wall of the esophagus with partial resection of cartilage without pyloroplasty through endoscopy is a novel practical surgical approach to treat patients with TBR.

RNA editing in mesothelioma: a look forward.

RNA editing is a post-transcriptional process increasing transcript diversity, thereby regulating different biological processes. We recently observed that mutations resulting from RNA editing due to hydrolytic deamination of adenosine increase during the development of mesothelioma, a rare cancer linked to chronic exposure to asbestos. This review gathers information from the published literature and public data mining to explore several aspects of RNA editing and their possible implications for cancer growth and therapy. We address possible links between RNA editing and particular types of mesothelioma genetic and epigenetic alterations and discuss the relevance of an edited substrate in the context of current chemotherapy or immunotherapy.

Can early surgery improve the outcome of patients with meconium peritonitis? A single-center experience over 16 years.

BACKGROUND: In the last century, meconium peritonitis(MP)was once a highly fatal gastrointestinal. disease With the development of fetal radiological technology, abnormal signs, such as pseudocysts, can. be detected during the fetal period so that more patients can be diagnosed prenatally and receive surgery. in the early stage of life. The survival rate of MP has increased up to 80% in recent years. According to. a review of the treatment and outcomes of patients diagnosed with MP, we evaluated the influence of. early operation on survival rate and discussed the risk factors of prognosis. METHODS: We collected 79 cases of patients diagnosed with MP who were treated in our department. from October 2001 to December 2017. They were divided into 2 groups. Patients in group A were born. in our hospital. Patients in group B were born in a local hospital with suspicion of MP and then transferred. to our department. RESULTS: The birth weight (BW) and gestational age (GA) of patients were higher in group A than in. group B. There was no significant difference in the proportion of premature and low birth weight (LBW). patients between the two groups (p = 0.422, p = 0.970). Their age at the time of surgery was younger in. group A than in group B (1.4 ± 2.0 vs. 6.9 ± 14.9, p < 0.001). The overall survival rate of group A was higher. than that of group B (95.0% vs. 79.5%, p = 0.038). The prognosis of premature patients was worse than. that of full-term infants for both groups (p = 0.012). CONCLUSIONS: Prematurity is a significant risk factor related to death for MP patients. The survival rate. of MP patients can be improved by early operation during the neonatal period.

Elongation of esophageal segments by bougienage stretching technique for long gap esophageal atresia to achieve delayed primary anastomosis by thoracotomy or thoracoscopic repair: A first experience from China.

OBJECTIVES: The treatment of long gap esophageal atresia (LGEA) is one of the most challenging congenital malformations in neonatal surgery. A preoperative bougienage stretching technique for elongation of the two segments of esophagus is applied to achieve utilizing the native esophagus to establish esophageal continuity by open or thoracoscopic approach. METHODS: From January 2015 to May 2017, 12 neonates who suffered from LGEA were admitted to our department. They were divided into 2 groups (A and B) according to their admission time. They all accepted bougienage stretching technique before esophageal anastomosis. RESULTS: Initially the lengths of esophageal gap in 12 infants ranged from 4 to 7.5 vertebral bodies (M=5.8±1.1). The gap lengths became -1 to 2.5 vertebral bodies after bougienage stretching technique and tension-free anastomosis were performed successfully for all 12 cases: Group A (n=5) by thoracotomy and group B (n=7) by thoracoscopic approach. 12 cases have been followed up for 1-25 months (M=12.4±8.5) after definitive surgery. CONCLUSIONS: Bougienage stretching technique for LGEA is feasible with satisfactory clinical results. Thoracoscopic approach is a good choice for primary anastomosis in LGEA. LEVELS OF EVIDENCE: Treatment Study Level IV.