Lnc SMAD5-AS1 as ceRNA inhibit proliferation of diffuse large B cell lymphoma via Wnt/\u03b2-catenin pathway by sponging miR-135b-5p to elevate expression of APC

Chen-Chen Zhao,Yi-Yin Zhang,Yi-Ruo Zhang,Gu Kang-Sheng,Yang Jiao,Jing Xu,Wei Wei,Jie Ning

doi:10.1038/s41419-019-1479-3

Abstract

Diffuse large B cell lymphoma (DLBCL) is a common and fatal hematological malignancy. Long noncoding RNAs (lncRNAs) have emerged as crucial biomarkers and regulators in many cancers. Novel lncRNA biomarker in DLBCL needs to be investigated badly, as well as its function and molecular mechanism. To further explore, microarray analysis was performed to identify the differentially expressed lncRNAs in DLBCL tissues. To investigate the biological functions of SMAD5-AS1, we performed gain- and loss-of-function experiments in vitro and in vivo. Furthermore, bioinformatics analysis, dual-luciferase reporter assays, Argonaute 2-RNA immunoprecipitation (AGO2-RIP), RNA pull-down assay, quantitative PCR arrays, western blot assay, TOPFlash/FOPFlash reporter assay, and rescue experiments were conducted to explore the underlying mechanisms of competitive endogenous RNAs (ceRNAs). We found that SMAD5-AS1 was down-regulated in DLBCL tissues and cell lines. Functionally, SMAD5-AS1 downregulation promoted cell proliferation in vitro and in vivo, whereas SMAD5-AS1 overexpression could lead to the opposite effects in vitro and in vivo. Bioinformatics analysis and luciferase assays revealed that miR-135b-5p was a direct target of SMAD5-AS1, which was validated by dual-luciferase reporter assays, AGO2-RIP, RNA pull-down assay, and rescue experiments. Also, dual-luciferase reporter assays and rescue experiments demonstrated that miR-135b-5p targeted the adenomatous polyposis coli (APC) gene directly. SMAD5-AS1/miR-135b-5p inhibits the cell proliferation via inactivating the classic Wnt/β-catenin pathway in the form of APC dependency. Our results indicated that SMAD5-AS1 inhibits DLBCL proliferation by sponging miR-135b-5p to up-regulate APC expression and inactivate classic Wnt/β-catenin pathway, suggesting that SMAD5-AS1 may act as a potential biomarker and therapeutic target for DLBCL.

Highlights

Background Diffuse largeB cell lymphoma (DLBCL) is a kind of non-Hodgkin’s lymphoma, which accounts for about25–35% in non-Hodgkin’s lymphoma and 37% in B cell tumor in the world[1]
The function and regulation of this Long noncoding ribonucleic acid (LncRNA) remained unclear as few studies focused on it
LncRNAs related to diffuse large B cell lymphoma (DLBCL) have been studied in recent years

Summary

Introduction

Background Diffuse largeB cell lymphoma (DLBCL) is a kind of non-Hodgkin’s lymphoma, which accounts for about25–35% in non-Hodgkin’s lymphoma and 37% in B cell tumor in the world[1]. DLBCL is a highly aggressive diffuse malignant hyperplastic disease of the lymphatic system, and clinical therapeutic regimens used currently are ineffective in about 40% patients[2]. The reason for it is that there is a lack of obvious symptoms in the early stage of DLBCL and its pathogenesis remains unclear, so no effective targeted therapy has been found, leading to poor prognosis and low 5-year survival rate of only. The gene mutation varies from person to person, and it is even different in different cells in the same tumor, so no good therapeutic effect has been obtained in the signal molecule in COO typing or the targeted therapy for the original mutant gene products. There is an urgent need to find new targeted therapeutic molecules for DLBCL

Methods

Results

Conclusion