HBx induces hepatocellular carcinogenesis through ARRB1-mediated autophagy to drive the G1/S cycle

Autophagy. 2021 Dec;17(12):4423-4441. doi: 10.1080/15548627.2021.1917948. Epub 2021 Apr 27.

Abstract

The hepatitis B virus X protein (HBx) is involved in the process of hepatocellular carcinoma via the activation of various oncogenes. Our previous study indicated that ARBB1 (arrestin beta 1) promotes hepatocellular carcinogenesis (HCC). However, the role of ARRB1 in HBx-related HCC remains unclear. Herein, we identified that ARRB1 was upregulated by HBx in vivo and in vitro. Arrb1 deficiency suppressed HBx-induced hepatocellular carcinogenesis in several mouse models. Furthermore, knockdown of ARRB1 blocked HBx-induced macroautophagic/autophagic flux and disrupted the formation of autophagosomes. ARRB1 interacted with HBx, and the autophagic core protein MAP1LC3/LC3, a scaffolding protein, was essential for complete autophagy. Inhibition of autophagy by 3-methyladenine or interference of ATG5 or ATG7 attenuated HBx-induced cell cycle acceleration and the subsequent proliferative response via the induction of G1/S arrest. The absence of autophagy abolished the phosphorylation of CDK2 and the activity of the CDK2-CCNE1 complex. Our results demonstrate that ARRB1 plays a critical role in HBV-related HCC via modulating autophagy and the CDKN1B-CDK2-CCNE1-E2F1 axis and indicate that ARRB1 may be a potential therapeutic target for HCC.Abbreviations: ARRB1: arrestin beta 1; ACTB: actin beta; AMPK: adenosine monophosphate (AMP)-activated protein kinase; ATG5: autophagy related 5; ATG7: autophagy related 7; Baf A1: bafilomycin A1; CDK2: cyclin dependent kinase 2; CDKN1B/p27Kip1: cyclin dependent kinase inhibitor 1B; CQ: chloroquine; E2F1: E2F transcription factor 1; FBS: fetal bovine serum; GPCRs: G protein-coupled receptors; GST: glutathione S-transferase; HCC: hepatocellular carcinoma; HBV: hepatitis B virus; HBx: hepatitis B virus X protein; HMGB1: high mobility group box 1; HIF1A/HIF-1α: hypoxia inducible factor 1 subunit alpha; IHC: immunohistochemistry; JAK1: Janus kinase 1; LOX: lysyl oxidase; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MKI67: marker of proliferation Ki-67; MTOR: mechanistic target of rapamycin kinase; MAPK: mitogen-activated protein kinase; 3-MA: 3-methyladenine; NFKB/NF-κB: nuclear factor kappa B; PIK3CA: phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PHHs: primary human hepatocytes; RB1: RB transcriptional corepressor 1; SQSTM1/p62: sequestosome 1; STAT: signal transducer and activator of transcription; TACR1/NK1R: tachykinin receptor 1.

Keywords: ARRB1; autophagy; cell cycle; hepatitis B virus X protein; hepatocellular carcinoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagosomes / metabolism
  • Autophagy / physiology
  • Carcinogenesis / metabolism
  • Carcinoma, Hepatocellular* / genetics
  • Carcinoma, Hepatocellular* / metabolism
  • Cell Cycle
  • Liver Neoplasms* / genetics
  • Liver Neoplasms* / metabolism
  • Mice
  • Trans-Activators*
  • Viral Regulatory and Accessory Proteins*
  • beta-Arrestin 1* / metabolism

Substances

  • Arrb1 protein, mouse
  • Trans-Activators
  • Viral Regulatory and Accessory Proteins
  • beta-Arrestin 1
  • hepatitis B virus X protein

Grants and funding

Funding: This project was partially supported by the National Natural Science Foundation of China [82070574, 81602122], the Natural Science Foundation Team Project of Guangdong Province [2018B030312009], and the Breeding Foundation for Young Pioneers’ Research of Sun Yat-sen University (17ykpy53);Young Teacher Foundation of Sun Yat-sen University [17ykpy53];