Surgical Outcome of Renal Cell Carcinoma with Tumor Thrombus Extension into Inferior Vena Cava and Right Atrium (Beating Heart Removal of Level 4 Thrombus): A Challenging Scenario

Aim: “To evaluate oncological and surgical outcomes of different levels of tumor thrombus and tumor characteristics secondary to renal cell carcinoma (RCC)”. Materials and Methods: Retrospective review from 2013 to 2020 of 34 patients who underwent radical nephrectomy with thrombectomy for RCC with tumor thrombus extending into the inferior vena cava (IVC) and right atrium (RA) at our center. Level I and most level II tumors were removed using straight forward occluding maneuvers with control of the contralateral renal vein. None of the patients had level III tumor extensions in our study group. For level IV thrombus, a beating heart surgery using a simplified cardiopulmonary bypass (CPB) technique was used for retrieval of thrombus from the right atrium. Results: “Of the 34 patients with thrombus”, 19 patients had level I, 12 patients had level II, none had level III, and three patients had level IV thrombus. Two patients required simplified CPB. Another patient with level IV thrombus CPB, was not attempted in view of refractory hypotension intraoperatively. Pathological evaluation showed clear-cell carcinoma in 67.64%, papillary carcinoma in 17.64%, chromophobe in 5.8%, and squamous cell carcinoma in 8.8% of cases. Left side thrombectomy was difficult surgically, whereas right side thrombectomy did not have any survival advantage. Mean blood loss during the procedure was 325 mL, ranging from 200 to 1000 mL, and mean operative time was 185 min, ranging from 215 to 345 min. The immediate postoperative mortality was 2.9%. Level I thrombus had better survival compared to level II thrombus. Conclusion: Radical nephrectomy with tumor thrombectomy remains the mainstay of treatment in RCC with inferior venacaval extension. The surgical approach and outcome depends on primary tumor size, location, level of thrombus, local invasion of IVC, any hepato-renal dysfunction or any associated comorbidities. The higher the level of thrombus, the greater is the need for prior optimization and the adoption of a multidisciplinary approach for a successful surgical outcome

RyR2/IRBIT regulates insulin gene transcript, insulin content, and secretion in the insulinoma cell line INS-1

The role of ER Ca2+ release via ryanodine receptors (RyR) in pancreatic β‐cell function is not well defined. Deletion of RyR2 from the rat insulinoma INS‐1 (RyR2KO) enhanced IP3 receptor activity stimulated by 7.5 mM glucose, coincident with reduced levels of the protein IP3 Receptor Binding protein released with Inositol 1,4,5 Trisphosphate (IRBIT). Insulin content, basal (2.5 mM glucose) and 7.5 mM glucose‐stimulated insulin secretion were reduced in RyR2KO and IRBITKO cells compared to controls. INS2 mRNA levels were reduced in both RyR2KO and IRBITKO cells, but INS1 mRNA levels were specifically decreased in RyR2KO cells. Nuclear localization of S‐adenosylhomocysteinase (AHCY) was increased in RyR2KO and IRBITKO cells. DNA methylation of the INS1 and INS2 gene promotor regions was very low, and not different among RyR2KO, IRBITKO, and controls, but exon 2 of the INS1 and INS2 genes was more extensively methylated in RyR2KO and IRBITKO cells. Exploratory proteomic analysis revealed that deletion of RyR2 or IRBIT resulted in differential regulation of 314 and 137 proteins, respectively, with 41 in common. These results suggest that RyR2 regulates IRBIT levels and activity in INS‐1 cells, and together maintain insulin content and secretion, and regulate the proteome, perhaps via DNA methylation

Impact on patterns of tobacco and its initiation among children of conflict area in Jammu and Kashmir (India): a school based study

Background School going children are becoming target of Tobacco Industry and is a serious issue in disturbed areas of India particularly Kashmir. The early age of initiation underscores the urgent need to intervene and protect this vulnerable group from falling prey to this addiction. The present study was thus undertaken to assess the prevalence of tobacco habits (Patterns) among school children, determine the age & major reasons of initiation of these habits, and compare the age of initiation between students who were more than 15 and ≤ 18 yr of age. Methods Through cluster and random sampling method, private and government schools of Kashmir valley (10 Districts) of Jammu and Kashmir were identified for the study. In identified schools a structured questionnaire was administered among students of class 7 to 12 (aged 11-19 yr). The data entry was done in further descriptive and exploratory data analysis was done manually. Results It is found that 18.4% students; 375 (14.1%) were 'ever smokers (including current smokers), 111(4.1%) were 'ever tobacco chewers (including current chewers)', (11.94%) were 'exclusive smokers' and (3.5%) were 'exclusive tobacco chewers'. 512 (19.3%) children belong to families affected by unrest and suffered economic loss from last 3 years. The mean age of initiation of these habits was around 10.4 year. Nearly 75 % of boys and 6% of girls ≤ 15 yr initiated the habit of tobacco before the age of 12yr. Conclusions The study concludes that Tobacco use in Kashmir (State J&K) among children is higher than the national average, the conflict in the region may be the one of main reason behind it. It also highlight the alarming fact that age initiation among these areas is much lower than the state average. Customized policy intervention is required to control the tobacco use among children in conflict area

Effect of Disease-Associated Germline Mutations on Structure Function Relationship of DNA Methyltransferases

Despite a large body of evidence supporting the role of aberrant DNA methylation in etiology of several human diseases, the fundamental mechanisms that regulate the activity of mammalian DNA methyltransferases (DNMTs) are not fully understood. Recent advances in whole genome association studies have helped identify mutations and genetic alterations of DNMTs in various diseases that have a potential to affect the biological function and activity of these enzymes. Several of these mutations are germline-transmitted and associated with a number of hereditary disorders, which are potentially caused by aberrant DNA methylation patterns in the regulatory compartments of the genome. These hereditary disorders usually cause neurological dysfunction, growth defects, and inherited cancers. Biochemical and biological characterization of DNMT variants can reveal the molecular mechanism of these enzymes and give insights on their specific functions. In this review, we introduce roles and regulation of DNA methylation and DNMTs. We discuss DNMT mutations that are associated with rare diseases, the characterized effects of these mutations on enzyme activity and provide insights on their potential effects based on the known crystal structure of these proteins

Dnmt3bas coordinates transcriptional induction and alternative exon inclusion to promote catalytically active Dnmt3b expression

Summary: Embryonic expression of DNMT3B is critical for establishing de novo DNA methylation. This study uncovers the mechanism through which the promoter-associated long non-coding RNA (lncRNA) Dnmt3bas controls the induction and alternative splicing of Dnmt3b during embryonic stem cell (ESC) differentiation. Dnmt3bas recruits the PRC2 (polycomb repressive complex 2) at cis-regulatory elements of the Dnmt3b gene expressed at a basal level. Correspondingly, Dnmt3bas knockdown enhances Dnmt3b transcriptional induction, whereas overexpression of Dnmt3bas dampens it. Dnmt3b induction coincides with exon inclusion, switching the predominant isoform from the inactive Dnmt3b6 to the active Dnmt3b1. Intriguingly, overexpressing Dnmt3bas further enhances the Dnmt3b1:Dnmt3b6 ratio, attributed to its interaction with hnRNPL (heterogeneous nuclear ribonucleoprotein L), a splicing factor that promotes exon inclusion. Our data suggest that Dnmt3bas coordinates alternative splicing and transcriptional induction of Dnmt3b by facilitating the hnRNPL and RNA polymerase II (RNA Pol II) interaction at the Dnmt3b promoter. This dual mechanism precisely regulates the expression of catalytically active DNMT3B, ensuring fidelity and specificity of de novo DNA methylation

SMYD3 represses tumor-intrinsic interferon response in HPV-negative squamous cell carcinoma of the head and neck

Summary: Cancers often display immune escape, but the mechanisms are incompletely understood. Herein, we identify SMYD3 as a mediator of immune escape in human papilloma virus (HPV)-negative head and neck squamous cell carcinoma (HNSCC), an aggressive disease with poor response to immunotherapy with pembrolizumab. SMYD3 depletion induces upregulation of multiple type I interferon (IFN) response and antigen presentation machinery genes in HNSCC cells. Mechanistically, SMYD3 binds to and regulates the transcription of UHRF1, encoding for a reader of H3K9me3, which binds to H3K9me3-enriched promoters of key immune-related genes, recruits DNMT1, and silences their expression. SMYD3 further maintains the repression of immune-related genes through intragenic deposition of H4K20me3. In vivo, Smyd3 depletion induces influx of CD8+ T cells and increases sensitivity to anti-programmed death 1 (PD-1) therapy. SMYD3 overexpression is associated with decreased CD8 T cell infiltration and poor response to neoadjuvant pembrolizumab. These data support combining SMYD3 depletion strategies with checkpoint blockade to overcome anti-PD-1 resistance in HPV-negative HNSCC