TAF1B depletion leads to apoptotic cell death by inducing nucleolar stress and activating p53-miR-101 circuit in hepatocellular carcinoma

Hang-Fei Chen; Dan-Dan Gao; Xin-Qing Jiang; Hao Sheng; Qi Wu; Quan Zheng; Qiao-Cheng Zhai; Lei Yuan; Ming Liu; Li-Feng Xu; Mao-Xiang Qian; Heng Xu; Jian Fang; Feng Zhang

doi:10.3389/fonc.2023.1203775

TAF1B depletion leads to apoptotic cell death by inducing nucleolar stress and activating p53-miR-101 circuit in hepatocellular carcinoma

Front Oncol. 2023 Aug 14:13:1203775. doi: 10.3389/fonc.2023.1203775. eCollection 2023.

Authors

Hang-Fei Chen^{1

2}, Dan-Dan Gao², Xin-Qing Jiang¹, Hao Sheng³, Qi Wu², Quan Zheng², Qiao-Cheng Zhai², Lei Yuan⁴, Ming Liu⁵, Li-Feng Xu⁵, Mao-Xiang Qian^{6

7}, Heng Xu^{7

8}, Jian Fang⁴, Feng Zhang^{1

2

7}

Affiliations

¹ The 2nd Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China.
² Core Facility, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
³ Department of Anus & Intestine Surgery, The First People's Hospital of Jiande, Hangzhou, Zhejiang, China.
⁴ Department of Hepatobiliary Surgery, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
⁵ The Joint Innovation Center for Engineering in Medicine, Quzhou People's Hospital, Quzhou, China.
⁶ Institute of Pediatrics and Department of Hematology and Oncology, National Children's Medical Center, Children's Hospital of Fudan University, Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
⁷ Center for Precision Medicine, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
⁸ Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China.

Abstract

Background: TAF1B (TATA Box Binding Protein (TBP)-Associated Factor) is an RNA polymerase regulating rDNA activity, stress response, and cell cycle. However, the function of TAF1B in the progression of hepatocellular carcinoma (HCC) is unknown.

Objective: In this study, we intended to characterize the crucial role and molecular mechanisms of TAF1B in modulating nucleolar stress in HCC.

Methods: We analyzed the differential expression and prognostic value of TAF1B in hepatocellular carcinoma based on The Cancer Genome Atlas (TCGA) database, tumor and paraneoplastic tissue samples from clinical hepatocellular carcinoma patients, and typical hepatocellular carcinoma. We detected cell proliferation and apoptosis by lentiviral knockdown of TAF1B expression levels in HepG2 and SMMC-7721 cells using clone formation, apoptosis, and Western blotting (WB) detection of apoptosis marker proteins. Simultaneously, we investigated the influence of TAF1B knockdown on the function of the pre-initiation complex (PIC) by WB, and co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation (ChIP) assays verified the interaction between the complexes and the effect on rDNA activity. Immunofluorescence assays measured the expression of marker proteins of nucleolus stress, fluorescence in situ hybridization (FISH) assays checked the rDNA activity, and qRT-PCR assays tested the pre-rRNA levels. Regarding molecular mechanisms, we investigated the role of p53 and miR-101 in modulating nucleolar stress and apoptosis. Finally, the impact of TAF1B knockdown on tumor growth, apoptosis, and p53 expression was observed in xenograft tumors.

Result: We identified that TAF1B was highly expressed in hepatocellular carcinoma and associated with poor prognosis in HCC patients. TAF1B depletion modulated nucleolar stress and apoptosis in hepatocellular carcinoma cells through positive and negative feedback from p53-miR-101. RNA polymerase I transcription repression triggered post-transcriptional activation of miR-101 in a p53-dependent manner. In turn, miR-101 negatively feeds back through direct inhibition of the p53-mediated PARP pathway.

Conclusion: These findings broaden our comprehension of the function of TAF1B-mediated nucleolar stress in hepatocellular carcinoma and may offer new biomarkers for exploring prospective therapeutic targets in HCC.

Keywords: RNA polymerase I; TAF1B; hepatocellular carcinoma; miR-101; nucleolar stress; p53.

Grants and funding

This work was supported by the Natural Science Foundation of China [81502304], Natural Science Foundation of Zhejiang Province [LGF22G010009], Medical and Health Technology Projects of Zhejiang Province [2017KY696, 2019PY089], Chinese Medicine Science Foundation of Zhejiang Province [2021ZB328], and Quzhou technology projects, China [2022K46].