Exosomal circRNA as a novel potential therapeutic target for multiple myeloma-related peripheral neuropathy.

Peripheral neuropathy (PN) is an incurable complication of multiple myeloma (MM) which adversely affects patients' quality of life. The important roles that Circular RNAs (circRNAs) play in tumor progression, and exosome-mediated intracellular communication has been recognized as a crucial factor in the pathogenesis of MM. However, the role of exosome-derived circRNAs (exo-circRNAs) in MM and MM-induced PN remains elusive. In this study, we aimed to investigate the correlation between serum exo-circRNAs and MM to preliminarily explore the role of exo-circRNAs in MM-related PN. A cohort of 25 MM patients and 5 healthy control (HC) individuals were enrolled in the study. High-throughput sequencing and qRT PCR validation of serum exo-circRNAs were used to generate the aberrantly expressed exo-circRNAs profiles. Bioinformatics analysis was done using GO, KEGG, miRanda, Targetscan and Metascape. Correlation analysis was conducted between chr2:2744228-2,744,407+ and clinical characteristics of PN. ROC curve, univariate and multivariate COX regression models were conducted to identify the prognostic potential of chr2:2744228-2,744,407+ in the MM-related PN. 265 upregulated circRNAs and 787 downregulated circRNAs, with at least a two-fold difference in expression level in MM patients vs HC, were screened. Bioinformatics analysis indicated that upregulated circRNAs had the potential to facilitate MM-related PN. Furthermore, PCR validated the abundant expression of chr2:2744228-2,744,407+ in the serum exosomes of 25 MM patients. Bioinformatics analysis indicated that chr2:2744228-2,744,407+ might induce MM related PN via the downstream miRNA and GRIN2B axis. Overexpressed chr2:2744228-2,744,407+ in the serum exosomes of MM patients might lead to the downregulation of hsa-miR-6829-3p, elevation of GRIN2B in the serum and PC12 cells, and inhibited cell viability. The correlation analysis indicated that the expression of chr 2:2744228-2,744,407+ was positively correlated with the clinical characteristics of PN. ROC curve, univariate and multivariate COX regression analysis identified that chr2:2744228-2,744,407+ is an independent prognostic factor in the MM related PN. We identified that the abnormal expression of the serum exo-circRNA was correlated with MM-related PN, implying that exo-circRNA has potential as a novel therapeutic target for MM related PN.