The involvement and therapeutic potential of lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 pathway in arsenic trioxide-induced cardiotoxicity.

BACKGROUND/AIMS: Arsenic trioxide (ATO) is the first-line therapeutic drug for acute promyelocytic leukemia. However, the cardiotoxicity of ATO limits its clinical application. This study aims to explore the long noncoding RNA (lncRNA) involved molecular mechanism in ATO-induced cardiotoxicity and to identify available prevention strategies. METHODS: ATO was administered to mice or primary cultured mouse cardiomyocytes. Small interfering RNA targeting lncRNA Kcnq1ot1 (si-Kcnq1ot1) was used to knockdown lncRNA Kcnq1ot1. MiR-34a-5p mimic and antisense morpholino oligonucleotide targeting miR-34a-5p (AMO-34a-5p) were used to upregulate and downregulate the expression of miR-34a-5p, respectively. TUNEL staining was conducted to detect cell DNA damage. Flow cytometry assay was used to detect cell apoptosis. Western blot was conducted to detect Bcl-2, Bax and Sirt1 protein expression. Real-time PCR was used to detect lncRNA Kcnq1ot1, miR-34a-5p, and Sirt1 mRNA expression. Dual-luciferase reporter assay was performed to validate the predicted binding site. RESULTS: ATO induced apoptosis in cardiomyocytes both in vivo and in vitro. Simultaneously, the expression of lncRNA Kcnq1ot1 and Sirt1 was downregulated, and miR-34a-5p was upregulated. MiR-34a-5p has binding sites with lncRNA Kcnq1ot1 and Sirt1. Knockdown of lncRNA Kcnq1ot1 induced apoptosis of cardiomyocytes, with increased miR-34a-5p and decreased Sirt1 expression. Inhibition of miR-34a-5p attenuated si-Kcnq1ot1-induced apoptosis in cardiomyocytes. Therefore, the lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 signaling pathway is involved in ATO-induced cardiotoxicity. Propranolol alleviated ATO-induced apoptosis in cardiomyocytes both in vivo and in vitro, which was related to the lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 signaling pathway. CONCLUSION: The lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 pathway is involved in ATO-induced cardiotoxicity. Propranolol can attenuate ATO-induced cardiotoxicity at least partially through the lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 pathway. Combined administration with propranolol may be a new strategy for alleviating the cardiotoxicity of ATO.

Integration of cancer stemness and neoantigen load to predict responsiveness to anti-PD1/PDL1 therapy.

Background: Anti-programmed cell death 1/programmed cell death ligand 1 (PD1/PDL1) therapy is an important part of comprehensive cancer therapy. However, many patients suffer from non-response to therapy. Tumor neoantigen burden (TNB) and cancer stemness play essential roles in the responsiveness to therapy. Therefore, the identification of drug candidates for anti-PD1/PDL1 therapy remains an unmet need. Methods: Three anti-PD1/PDL1 therapy cohorts were obtained from GEO database and published literatures. Cancer immune characteristics were analyzed using CIBERSORTX, GSVA, and ESTIMATE. WGCNA was employed to identify the gene modules correlated with cancer TNB and stemness. A machine-learning method was used to construct the immunotherapy resistance score (TSIRS). Pharmacogenomic analysis was conducted to explore the potential alternative drugs for anti-PD1/PDL1 therapy resistant patients. CCK-8 assay, EdU assay and wound healing assay were used to validate the effect of the predicted drug on cancer cells. Results: The therapy response and non-response cancer groups have different microenvironment features. TSIRS was developed based on tumor neoantigen and stemness. TSIRS can effectively predict the outcomes of patients with anti-PD1/PDL1 therapy in training, validation and meta cohorts. Meanwhile, TSIRS can reflect the characteristics of tumor microenvironment during anti-PD1/PDL1 therapy. PF-4708671 is identified as a potential alternative drug for patients with resistance to anti-PD1/PDL1 therapy. It possesses significant inhibitive effect on the proliferation and migration of BGC-823 cells. Conclusion: TSIRS is an effective tool in the identification of candidate patients who will be benefit from anti-PD1/PDL1 therapy. Small molecule drug PF-4708671 has the potential to be used in anti-PD1/PDL1 therapy resistant patients.

The whole transcriptome analysis and the circRNA-lncRNA network construction in arsenic trioxide-treated mice myocardium.

BACKGROUND/AIMS: Arsenic trioxide (ATO) is an effective anti-cancer drug. Nonetheless, it possesses cardiotoxic effects which limit its clinical application. The present study aims to elucidate the molecular basis of ATO-induced cardiotoxicity through using whole transcriptome analysis. METHODS: The whole transcriptome in ATO-treated mice myocardium was analyzed using RNA sequencing technique. These results were confirmed by real-time PCR. The lncRNA-mRNA and circRNA-mRNA co-expression networks were constructed. Finally, a circRNA-lncRNA co-regulated competing endogenous RNA (ceRNA) network was constructed. GO and KEGG pathway analyses were performed. The expression levels of Txnip and Spp1 in ATO-treated neonatal mouse cardiomyocytes were validated by real-time PCR. RESULTS: A total of 113 mRNAs, 159 lncRNAs, 35 miRNAs, and 94 circRNAs were differentially expressed in ATO-treated mice myocardium. A lncRNA-circRNA co-regulation network was constructed. Function annotation revealed that aberrantly expressed genes may be enriched in the 'Wnt signaling pathway', 'Hippo signaling pathway', 'Notch signaling pathway', etc. Finally, the expression levels of Txnip and Spp1 were validated in ATO-treated cardiomyocytes, which was in accordance with the RNA-sequencing results. CONCLUSION: ATO altered coding and noncoding RNA profiles in myocardium of mice. The ATO-related lncRNA-circRNA co-regulation network was constructed. Genes in the co-regulation network are likely to play important roles in the cardiotoxicity of ATO. This study provides new insights into the prevention and treatment of ATO-induced cardiotoxicity.