NLS-RARα contributes to differentiation block and increased leukemogenic potential in vivo

Ling Xiong; Liang Zhong; Lihua Yu; Wenran Dan; Jiao Ye; Jian Li; Dongdong Liu; Zhen Yuan; Juanjuan Yao; Pengqiang Zhong; Junmei Liu; Beizhong Liu

doi:10.1016/j.cellsig.2019.109431

NLS-RARα contributes to differentiation block and increased leukemogenic potential in vivo

Cell Signal. 2020 Jan:65:109431. doi: 10.1016/j.cellsig.2019.109431. Epub 2019 Oct 22.

Authors

Ling Xiong¹, Liang Zhong², Lihua Yu¹, Wenran Dan¹, Jiao Ye², Jian Li², Dongdong Liu², Zhen Yuan², Juanjuan Yao¹, Pengqiang Zhong¹, Junmei Liu¹, Beizhong Liu³

Affiliations

¹ Central Laboratory of Yong-Chuan Hospital, Chongqing Medical University, Chongqing, 402160, China; Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
² Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
³ Central Laboratory of Yong-Chuan Hospital, Chongqing Medical University, Chongqing, 402160, China; Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China. Electronic address: liubeizhong@cqmu.edu.cn.

PMID: 31654721
DOI: 10.1016/j.cellsig.2019.109431

Abstract

The fusion oncogene, promyelocytic leukemia (PML)-retinoic acid receptor-α (RARα), is crucial for acute promyelocytic leukemia (APL) pathogenesis. Previous studies have reported that PML-RARα is cleaved by neutrophil elastase (NE), an early myeloid-specific serine protease, leading to translocation of the nuclear localization signal (NLS) of the PML protein to the N-terminal of RARα. This study was designed to evaluate the value of NLS-RARα in the early diagnosis of APL. To investigate the potential functional role of NLS-RARα in leukemogenesis, HL-60 and U937 cell lines were transfected with NLS-RARα lentivirus and negative control (LVNC). The results showed that the induced expression of NLS-RARα down-regulated expressions of CD11b, CD11c, and CD14 compared to the LVNC group induced by 1α, 25-dihydroxyvitamin D₃(1,25(OH)₂D₃). This suggested that NLS-RARα overexpression inhibited granulocytic and monocytic differentiation of myeloid leukemia cells. In addition, Wright-Giemsa staining, flow cytometry, respiratory burst assay, and NBT reduction assay all confirmed the importance of NLS-RARα in differentiation. The mechanistic investigations revealed that induced NLS-RARα expression inhibited 1,25(OH)₂D₃-induced granulocytic differentiation by regulating the cell cycle regulators p19^INK4D, p21^WAF1/CIP1, cyclinD1, cyclin E1, and pRB. Furthermore, the cleaved protein NLS-RARα enhanced the oncogenicity of U937 cells in NOD/SCID mice. These findings collectively demonstrated that NLS-RARα blocked granulocytic and monocytic differentiation of myeloid leukemia cells by inhibiting the downstream targets of the RARα signal pathway and the cell cycle. This may provide a promising new target and method for diagnosing and treating APL.

Keywords: APL; Cell cycle; Differentiation; NLS-RARα; Target diagnosis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Calcitriol / pharmacology
Carcinogenesis / drug effects
Carcinogenesis / pathology*
Cell Cycle / drug effects
Cell Differentiation* / drug effects
Cell Line, Tumor
Female
Humans
Leukemia, Promyelocytic, Acute / pathology*
Mice, Inbred NOD
Mice, SCID
Nuclear Localization Signals / metabolism*
Retinoic Acid Receptor alpha / chemistry*
Retinoic Acid Receptor alpha / metabolism*
Structure-Activity Relationship

Substances

Nuclear Localization Signals
Retinoic Acid Receptor alpha
Calcitriol