Large-Scale Application of Double-Stranded RNA Shows Potential for Reduction of Sacbrood Virus Disease in Apis cerana Apiaries.

Sacbrood virus (SBV) infection has emerged as a remarkable threat to Apis cerana colonies in South Korea, necessitating prompt control measures. In this study, RNA interference (RNAi) targeting the VP3 gene was developed to assess its safety and efficacy in protecting and treating SBV in vitro and in infected colonies in South Korean apiaries. The efficacy of VP3 double-stranded RNA (dsRNA) was demonstrated in laboratory-based experiments, wherein infected larvae treated with VP3 dsRNA exhibited a 32.7% increase in survival rate compared to untreated larvae. Data from a large-scale field trial indicate the efficacy of dsRNA treatment since none of the treated colonies had symptomatic SBV infections, whereas disease was observed in 43% (3/7) of the control colonies. In the 102 colonies exhibiting symptoms of SBV disease, RNAi treatment provided partial protection with weekly treatment, prolonging the survival period of colonies to 8 months compared to 2 months in colonies treated at 2- and 4-week intervals. Therefore, this study demonstrated that RNAi is a valuable tool for preventing SBV disease outbreaks in healthy and low-level SBV-infected colonies.

ASXL1 mutations are associated with distinct epigenomic alterations that lead to sensitivity to venetoclax and azacytidine.

The BCL2-inhibitor, Venetoclax (VEN), has shown significant anti-leukemic efficacy in combination with the DNMT-inhibitor, Azacytidine (AZA). To explore the mechanisms underlying the selective sensitivity of mutant leukemia cells to VEN and AZA, we used cell-based isogenic models containing a common leukemia-associated mutation in the epigenetic regulator ASXL1. KBM5 cells with CRISPR/Cas9-mediated correction of the ASXL1G710X mutation showed reduced leukemic growth, increased myeloid differentiation, and decreased HOXA and BCL2 gene expression in vitro compared to uncorrected KBM5 cells. Increased expression of the anti-apoptotic gene, BCL2, was also observed in bone marrow CD34+ cells from ASXL1 mutant MDS patients compared to CD34+ cells from wild-type MDS cases. ATAC-sequencing demonstrated open chromatin at the BCL2 promoter in the ASXL1 mutant KBM5 cells. BH3 profiling demonstrated increased dependence of mutant cells on BCL2. Upon treatment with VEN, mutant cells demonstrated increased growth inhibition. In addition, genome-wide methylome analysis of primary MDS samples and isogenic cell lines demonstrated increased gene-body methylation in ASXL1 mutant cells, with consequently increased sensitivity to AZA. These data mechanistically link the common leukemia-associated mutation ASXL1 to enhanced sensitivity to VEN and AZA via epigenetic upregulation of BCL2 expression and widespread alterations in DNA methylation.

Sphingosine Induces Apoptosis and Down-regulation of MYCN in PAX3-FOXO1-positive Alveolar Rhabdomyosarcoma Cells Irrespective of TP53 Mutation.

BACKGROUND/AIM: Rhabdomyosarcoma is the most common type of pediatric soft-tissue sarcoma. Among the subsets of this disease, alveolar rhabdomyosarcoma (ARMS) expressing paired box 3 (PAX3) and forkhead box O1 (PAX3-FOXO1) fusion oncoprotein has the worst prognosis. The goal of this study was to investigate the chemotherapeutic effects of sphingosine on PAX3-FOXO1-positive ARMS cells [tumor protein p53 (TP53)-mutated RH30 and TP53 wild-type RH18 cells]. MATERIALS AND METHODS: The proliferation, cell death, apoptosis, cell cycle, and MYCN proto-oncogene (MYCN) expression of RH30 and RH18 cells were determined. RESULTS: Sphingosine inhibited the growth and caused cell death in a dose-dependent manner in both cell lines. Sphingosine triggered cell death by inducing apoptosis without affecting the cell cycle. MYCN expression was down-regulated within 2 and 4 h of sphingosine treatment in both RH30 and RH18 cells. CONCLUSION: Sphingosine exerts antiproliferative and pro-apoptotic effects via MYCN down-regulation independently of TP53 mutation status in PAX3-FOXO1-positive ARMS cells.