Ni Sun1, Chen-Yi Wang2, Yi-Qun Sun2, Ye-Jiao Ruan2, Yue-Yue Huang1, Tong Su1, Xiao-Hai Zhou1, He Huang1, Wen-Jian Guo1, Mu-Qing He1, Rong-Xin Yao1, Xiao-Ji Lin3. 1. Department of Haematology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China. 2. Department of Haematology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; School of the Second Clinical Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China. 3. Department of Haematology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China. Electronic address: linxiaoji321@163.com.
Abstract
BACKGROUND: Aberrant microRNA (miRNAs) have recently been proposed as important regulators in acquiring resistance to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in diffuse large B-cell lymphoma (DLBCL). The purpose of this study was to establish the role of miR-148b in the development of CHOP resistance in DLBCL. METHODS: The expression patterns of miR-148b, HDAC6, and Ezrin were detected in CHOP-resistant clinical specimens and a DLBCL cell line. miR-148b, HDAC6, and Ezrin in DLBCL cells were manipulated by cell transfection to explore the functional correlation between them. Cell viability was determined using a CCK-8 assay. RESULTS: We found that miR-148b levels were markedly reduced and that the protein expressions of HDAC6 and Ezrin were increased in DLBCL CHOP-resistant clinical specimens and the cell line CRL2631/CHOP. Indeed, HDAC6 decreased the acetylation of histones H3 and H4 in the miR-148b promoter to inhibit miR-148b expression in DLBCL. Moreover, down-regulated miR-148b encouraged CHOP resistance in CRL2631 cells and miR-148b sensitized CRL2631 cells. We further revealed that Ezrin was negatively regulated by miR-148b and that the knockdown of Ezrin significantly attenuated CHOP resistance in CRL2631 cells induced by miR-148b silencing. MiR-148b also sensitized CRL2631/CHOP cell xenografts to CHOP in mice. CONCLUSION: Our data indicated that the high level of HDAC6 inhibited miR-148b via maintaining the low acetylation of histones H3 and H4 in the miR-148b promoter, thus rescuing Ezrin expression and promoting CHOP resistance in DLBCL.
BACKGROUND: Aberrant microRNA (miRNAs) have recently been proposed as important regulators in acquiring resistance to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in diffuse large B-cell lymphoma (DLBCL). The purpose of this study was to establish the role of miR-148b in the development of CHOP resistance in DLBCL. METHODS: The expression patterns of miR-148b, HDAC6, and Ezrin were detected in CHOP-resistant clinical specimens and a DLBCL cell line. miR-148b, HDAC6, and Ezrin in DLBCL cells were manipulated by cell transfection to explore the functional correlation between them. Cell viability was determined using a CCK-8 assay. RESULTS: We found that miR-148b levels were markedly reduced and that the protein expressions of HDAC6 and Ezrin were increased in DLBCL CHOP-resistant clinical specimens and the cell line CRL2631/CHOP. Indeed, HDAC6 decreased the acetylation of histones H3 and H4 in the miR-148b promoter to inhibit miR-148b expression in DLBCL. Moreover, down-regulated miR-148b encouraged CHOP resistance in CRL2631 cells and miR-148b sensitized CRL2631 cells. We further revealed that Ezrin was negatively regulated by miR-148b and that the knockdown of Ezrin significantly attenuated CHOP resistance in CRL2631 cells induced by miR-148b silencing. MiR-148b also sensitized CRL2631/CHOP cell xenografts to CHOP in mice. CONCLUSION: Our data indicated that the high level of HDAC6 inhibited miR-148b via maintaining the low acetylation of histones H3 and H4 in the miR-148b promoter, thus rescuing Ezrin expression and promoting CHOP resistance in DLBCL.