WTAP promotes osteosarcoma tumorigenesis by repressing HMBOX1 expression in an m6A-dependent manner

Shijie Chen,Minghua Hu,Zhiyu Ding,Weiguo Wang,Jinsong Li,Shuang Zhi,Yi Peng,Yan Huang,Jianlong Wang,Ruping Zheng,Yuezhan Li,Haiyang Yu,Jinglei Miao

doi:10.1038/s41419-020-02847-6

Abstract

N6-methyladenosine (m6A) regulators are involved in the progression of various cancers via regulating m6A modification. However, the potential role and mechanism of the m6A modification in osteosarcoma remains obscure. In this study, WTAP was found to be highly expressed in osteosarcoma tissue and it was an independent prognostic factor for overall survival in osteosarcoma. Functionally, WTAP, as an oncogene, was involved in the proliferation and metastasis of osteosarcoma in vitro and vivo. Mechanistically, M6A dot blot, RNA-seq and MeRIP-seq, MeRIP-qRT-PCR and luciferase reporter assays showed that HMBOX1 was identified as the target gene of WTAP, which regulated HMBOX1 stability depending on m6A modification at the 3′UTR of HMBOX1 mRNA. In addition, HMBOX1 expression was downregulated in osteosarcoma and was an independent prognostic factor for overall survival in osteosarcoma patients. Silenced HMBOX1 evidently attenuated shWTAP-mediated suppression on osteosarcoma growth and metastasis in vivo and vitro. Finally, WTAP/HMBOX1 regulated osteosarcoma growth and metastasis via PI3K/AKT pathway. In conclusion, this study demonstrated the critical role of the WTAP-mediated m6A modification in the progression of osteosarcoma, which could provide novel insights into osteosarcoma treatment.

Highlights

Osteosarcoma is a primary malignant bone tumor that is common among childhood and adolescents worldwide[1]
We detected the expression of WTAP in 104 pairs of osteosarcoma tissue and the corresponding para-tumor tissues from The Third Xiangya Hospital of Central South University (TXHCSU)
The prognostic nomogram was used to predict the probabilities of overall survival rates of osteosarcoma patients, and the calibration curves showed has a good consistency between the prediction and the actual observation (Fig. 1f)

Summary

Introduction

Osteosarcoma is a primary malignant bone tumor that is common among childhood and adolescents worldwide[1]. A better understanding of molecular mechanism is urgent for developing novel therapeutic strategies for osteosarcoma. N6-methyladenosine (m6A) is the prominent dynamic mRNA modification, which is involved in various biological process by regulating mRNA translocation, translation, and stability[4]. It is catalyzed by m6A writer (methyltransferase), removed by erasers (RNA demethylases) and recognized by m6A readers, involving in various biological progression[5,6,7]. METTL169,10, METTL5, ZCCHC411, and Zc3h1312 were showed to play a critical role in compositing methyltransferase complex and facilitating m6A methylation[13]. The reader proteins are from YTH family, heterogeneous nuclear ribonucleoprotein (HNRP) family and insulin-like growth factor 2 mRNA-binding protein

Methods

Results

Conclusion