lncRNA MSTRG.29039.1 Promotes Proliferation by Sponging hsa-miR-12119 via JAK2/STAT3 Pathway in Multiple Myeloma

METTL3 facilitates multiple myeloma tumorigenesis by enhancing YY1 stability and pri-microRNA-27 maturation in m6A-dependent manner

Multiple myeloma (MM) is a pernicious plasma cell disorder and has a poor prognosis. N6-methyladenosine (m6A) is an abundant epigenetic RNA modification and is important in cancer progression. Nevertheless, the function of m6A and its regulator METTL3 in MM are rarely reported. Here, we identified the m6A "writers", METTL3, was enhanced in MM and found that Yin Yang 1 (YY1) and primary-miR-27a-3p were the potential target for METTL3. METTL3 promoted primary-miR-27a-3p maturation and YY1 mRNA stability in an m6A manner. YY1 also was found to facilitate miR-27a-3p transcription. METTL3 affected the growth, apoptosis, and stemness of MM cells through accelerating the stability of YY1 mRNA and the maturation of primary-miR-27a-3p in vitro and in vivo. Our results reveal the key function of the METTL3/YY1/miR-27a-3p axis in MM and may provide fresh insights into MM therapy.

Multiple Myeloma Side Population Cells Promote Dexamethasone Resistance of Main Population Cells through Exosome Metastasis of LncRNA SNHG16

Background

The emergence of dexamethasone (Dex) resistance limits its efficacy. Side population (SP) cells in MM have strong tumorigenicity. Nevertheless, the detailed effect by which SP cells regulate Dex resistance in MP cells has not been completely verified and needs to be further investigated.

Methods

SP and MP cells were sorted from RPMI-8226. mRNA expression and cell viability were analyzed using quantitative real-time PCR (qRT-PCR) and MTS assays, respectively. The presence of exosomal lncRNA SNHG16 was verified by transmission electron microscopy, differential ultracentrifugation, and qRT-PCR. Protein expression levels were measured using western blotting. Gain or loss function analyses were performed to demonstrate the role of SNHG16 in the Dex resistance of MP cells.

Results

Dex resistance of SP cells was remarkably stronger than that of MP cells. Compared with MP cells, the survival rate and Dex resistance of MP cells cotreated with SP cell-derived exosomes were increased. SNHG16 expression was significantly enhanced in SP cell-derived exosomes compared to MP cell-derived exosomes. SNHG16 expression was remarkably increased in MP cells transfected with OE-SNHG16 vectors, and Dex resistance of MP cells was enhanced. When SNHG16 was silenced in SP cells, the SNHG16 expression was downregulated in both SP cells and SP cell-derived exosomes. SNHG16 expression and Dex resistance were both remarkably downregulated in MP cells treated with SP-si-SNHG16-exosomes compared to MP cells treated with SP-si-NC-exosomes.

Conclusion

MM SP cells promote Dex resistance in MP cells through exosome metastasis of SNHG16.

The Expression of Serum lncRNA MIR17HG in Patients with Multiple Myeloma and Its Clinical Significance

Objective. Multiple myeloma (MM) represents a malignant tumor with abnormal proliferation of plasma cells. The current study sought to investigate the changes in serum lncRNA MIR17HG (long noncoding RNA miR-17-92a-1 cluster host gene) levels in MM patients and its values in assessing the accuracy of MM diagnosis and predicting diagnosis. Methods. First, 108MM patients and 85 healthy controls were enrolled as the study subjects. The serum levels of MIR17HG in all subjects were determined by RT-qPCR. MM patients were clinically staged according to the Durie-Salmon (DS) and international staging system (ISS), and the levels of serum MIR17HG were compared among patients at different stages. The correlation of serum MIR17H level with serum creatinine (Scr), lactate dehydrogenase (LDH), and albumin (ALB) was analyzed using the Pearson method. The accuracy of the serum MIR17HG level in identifying MM was evaluated using receiver operating characteristic curves. The progression-free survival (PFS) and overall survival (OS) curves of MM patients were plotted using the Kaplan–Meier method. Results. Serum MIR17HG levels were up-regulated in MM patients and elevated with the development of DS and ISS stages. The serum MIR17HG was positively correlated with Scr and LDH and negatively correlated with ALB in MM patients. Serum MIR17HG level >1.485 could evaluate the accuracy of identifying MM. The PFS and OS were significantly shortened in MM patients with elevated MIR17HG levels. Conclusion. Our findings collectively indicate that the serum MIR17HG can aid the evaluation of accurate MM identification, and a high serum MIR17HG level can predict poor prognosis of patients with MM.