Elevation of miR-302b prevents multiple myeloma cell growth and bone destruction by blocking DKK1 secretion

Zheyu Wu,Lin Cai,Yuanlong Xie,Yufeng Zhang,Yufan Zhu,Zhiqiang Yang,Fuling Zhou

doi:10.1186/s12935-021-01887-y

Zheyu Wu, Lin Cai + Show 5 more

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https://doi.org/10.1186/s12935-021-01887-y

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Abstract

BackgroundMyeloma bone disease (MBD) is a severe complication of multiple myeloma (MM) mainly due to an imbalance between enhanced osteoclast activity and reduced osteoblast function. Previous studies have demonstrated that miRNAs play a vital role in the osteogenic differentiation of mesenchymal stromal cells (MSCs) in MM. However, the value of miR‑302b in MBD remains to be further elucidated. The aim of this study is to explore the role of miR‑302b in the regulation of MBD osteogenic differentiation and evaluate the potential of a new therapeutic strategy for the clinical treatment of MBD.MethodOur previous research demonstrated that MiR-302b belongs to the miR-302 cluster and is able to inhibit tumor growth and osteolysis in an orthotopic osteosarcoma xenograft tumor mouse model. In this study, we first transfected miR-302b mimics, miR-302b inhibitor, and miR-302b NC into MM1.S and RPMI8226 MM cells to detect the correlation between miR-302b expression in the pathological specimens and the clinicopathological features by qPCR, the target correlation between miR-302b and DKK1 by immunohistochemistry, qPCR and Western blot, and the correlation between miR-302b and the Wnt/β-catenin signaling pathway by Western blot. The effect of miR-302b on osteoblastogenesis was also studied in a subperiosteal tumorigenesis model of NOD/SCID nude mice.ResultsWe found that increased miR-302b suppressed cell proliferation and induced cell apoptosis in RPMI 8226 and MM1.S cells. TargetScan online bioinformatic analysis predicted that miR-302b is able to bind to 3′UTR of DKK1 mRNA. Target binding of miR-302b to DKK1 was demonstrated by dual-luciferase reporter assay, qPCR, Western blot and immunohistochemistry, indicating that miR-302b is able to degrade DKK1 in RPMI 8226 and MM1.S cells. The model of co-culturing MM cells with preosteoblast MC3T3-E1 cells showed that miR-302b inhibits MM-induced suppression of osteoblast differentiation. Western blotting showed that miR-302b promotes the Wnt/β-catenin signaling pathway in MM cells. Micro-CT and immunohistochemistry results showed that miR-302b suppresses myeloma bone destruction in vivo.ConclusionmiR-302b is able to target DKK1 and promote the Wnt/β-catenin signaling pathway in MM.

Highlights

Myeloma bone disease (MBD) is a severe complication of multiple myeloma (MM) mainly due to an imbalance between enhanced osteoclast activity and reduced osteoblast function
Target binding of miR-302b to DKK1 was demonstrated by dual-luciferase reporter assay, qPCR, Western blot and immunohistochemistry, indicating that miR-302b is able to degrade DKK1 in RPMI 8226 and MM1.S cells
The model of co-culturing MM cells with preosteoblast MC3T3-E1 cells showed that miR-302b inhibits MM-induced sup‐ pression of osteoblast differentiation

Summary

Introduction

Myeloma bone disease (MBD) is a severe complication of multiple myeloma (MM) mainly due to an imbalance between enhanced osteoclast activity and reduced osteoblast function. Previous studies have dem‐ onstrated that miRNAs play a vital role in the osteogenic differentiation of mesenchymal stromal cells (MSCs) in MM. Wu et al Cancer Cell Int (2021) 21:187 bone disease (MBD) is mainly caused by an imbalance of the bone remodeling process in the BM microenvironment, affecting about 70% of myeloma patients at the time of diagnosis [3]. Previous studies reported that MM cells can impair the normal physiological function of BM-derived stromal cells (BMSCs), osteoclasts and osteocytes [8,9,10]. The mutual regulation mechanism between MM cells and osteoblasts at different differentiation stages has not been elucidated

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