Journal Article

CD73 sustained cancer-stem-cell traits by promoting SOX9 expression and stability in hepatocellular carcinoma

Tang, Wei-Guo, Xie, Su-Hong, Lu, Ren-Quan, Hu, Bo, Ma, Xiao-Lu, Guo, Lin, Ren, Ning

2020

Overview

Background Aberrant AKT activation contributes to cancer stem cell (CSC) traits in hepatocellular carcinoma (HCC). We previously reported that CD73 activated AKT signaling via the Rap1/P110β cascade. Here, we further explored the roles of CD73 in regulating CSC characteristics of HCC. Methods CD73 expression modulations were conducted by lentiviral transfections. CD73+ fractions were purified by magnetic-based sorting, and fluorescent-activated cell sorting was used to assess differentiation potentials. A sphere-forming assay was performed to evaluate CSC traits in vitro, subcutaneous NOD/SCID mice models were generated to assess in vivo CSC features, and colony formation assays assessed drug resistance capacities. Stemness-associated gene expression was also determined, and underlying mechanisms were investigated by evaluating immunoprecipitation and ubiquitylation. Results We found CD73 expression was positively associated with sphere-forming capacity and elevated in HCC spheroids. CD73 knockdown hindered sphere formation, Lenvatinib resistance, and stemness-associated gene expression, while CD73 overexpression achieved the opposite effects. Moreover, CD73 knockdown significantly inhibited the in vivo tumor propagation capacity. Notably, we found that CD73+ cells exhibited substantially stronger CSC traits than their CD73– counterparts. Mechanistically, CD73 exerted its pro-stemness activity through dual AKT-dependent mechanisms: activating SOX9 transcription via c-Myc, and preventing SOX9 degradation by inhibiting glycogen synthase kinase 3β. Clinically, the combined analysis of CD73 and SOX9 achieved a more accurate prediction of prognosis. Conclusions Collectively, CD73 plays a critical role in sustaining CSCs traits by upregulating SOX9 expression and enhancing its protein stability. Targeting CD73 might be a promising strategy to eradicate CSCs and reverse Lenvatinib resistance in HCC.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: 5'-Nucleotidase - genetics / AKT protein / AKT signaling / Analysis / Animal models / Biochemistry / c-Myc protein / Cancer / Cancer Research / Cancer stem cells / Cancer therapies / Carcinoma / Carcinoma, Hepatocellular - genetics / Carcinoma, Hepatocellular - pathology / CD73 / CD73 antigen / Cell differentiation / Cell Line, Tumor / Development and progression / Drug resistance / Experiments / Gene expression / Gene Expression Regulation, Neoplastic / Genes / Genetic research / Glycogen / Glycogen synthase kinase 3 / Glycogen synthesis / GPI-Linked Proteins - genetics / Hematology / Hepatocellular carcinoma / Humans / Immunoprecipitation / Infection / Kinases / Laboratory animals / Lenvatinib / Lenvatinib resistance / Liver cancer / Liver Neoplasms - genetics / Liver Neoplasms - pathology / Medical prognosis / Medicine / Medicine & Public Health / Metastasis / Myc protein / Neoplastic Stem Cells - metabolism / Neoplastic Stem Cells - pathology / Oncology / Polysaccharides / Proteins / Rap1 protein / Sox9 protein / SOX9 Transcription Factor - analysis / SOX9 Transcription Factor - genetics / Spheroids / Stem cells / Studies / Transcription / Tumors / Ubiquitin