1. Aryl hydrocarbon receptor promotes hepatocellular carcinoma tumorigenesis by targeting intestine-specific homeobox expression
- Author
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Edward Hsi, Shyh Shin Chiou, Chi Cheng Wu, Chee Yin Chai, Shih Hsien Hsu, Li Ting Wang, and Shen-Nien Wang
- Subjects
Male ,0301 basic medicine ,Cancer Research ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,medicine.disease_cause ,Proto-Oncogene Mas ,Mice ,03 medical and health sciences ,Cell Line, Tumor ,Internal medicine ,Basic Helix-Loop-Helix Transcription Factors ,medicine ,Animals ,Humans ,E2F1 ,Molecular Biology ,Aged ,Cell Proliferation ,Homeodomain Proteins ,Oncogene ,biology ,Cell growth ,Liver Neoplasms ,Hep G2 Cells ,Middle Aged ,Cell cycle ,HCCS ,Aryl hydrocarbon receptor ,digestive system diseases ,Up-Regulation ,Gene Expression Regulation, Neoplastic ,Intestine-Specific Homeobox ,030104 developmental biology ,Endocrinology ,Receptors, Aryl Hydrocarbon ,biology.protein ,Cancer research ,Female ,Carcinogenesis ,Neoplasm Transplantation ,Transcription Factors - Abstract
The aryl hydrocarbon receptor (AHR), a major chemical sensor, is thought to play a role in various biological contexts, including cell cycle regulation and tumorigenesis. However, its regulatory mechanisms remain unclear. We propose herein a novel mechanism through which AHR promotes tumorigenesis by targeting expression of the oncogene intestine-specific homeobox (ISX) in hepatocellular carcinoma (HCC). Compared to paired tumor-adjacent tissues and non-HCC tumors, HCCs exhibited an increased and hierarchical pattern of AHR expression. Patients exhibiting high AHR expression had a significantly shorter survival duration, compared to those with low and medium expression. Functionally, AHR was found to target the newly discovered proto-oncogene, ISX, resulting in the increased expression of this gene and its downstream targets, CCND1 and E2F1. Ablation of AHR or ISX in hepatoma cells suppressed cell growth, whereas overexpression promoted cell proliferation and led to enhanced tumorigenic activity in vitro and in vivo. These results provide evidence to support a critical role for the AHR/ISX axis in HCC tumorigenesis and suggest its potential utility as a new therapeutic and prognostic target for HCC.
- Published
- 2017