The miR‐200b–ZEB1 circuit regulates diverse stemness of human hepatocellular carcinoma

Abstract

Accumulating evidence suggests that human hepatocellular carcinoma (HCC) can be derived from cancer stem cells (CSCs), which contribute to tumor initiation, metastasis, chemoresistance, and recurrence. A great variety of HCC CSCs resulting in diverse clinical manifestations have been reported. However, how CSC diversity is regulated and generated remains unclear. Here we report that the miR-200b-ZEB1 circuit is closely involved with the induction and maintenance of a diverse group of CSCs. We found that miR-200b downregulation occurred in early HCC and associated with poor prognosis. The downregulation was attributable to genome deletion and promoter methylation of the miR-200a/b/429 gene. Ectopic expression of miR-200b or silencing of ZEB1 led to a decrease in CD13 and CD24 HCC CSCs and an increase in EpCAM HCC CSCs. Mechanistically, miR-200b directly suppressed BMI1 and ZEB1 expressions. ZEB1 recognized promoters of CD13, CD24, and EpCAM genes resulting in CD13 and CD24 upregulation and EpCAM downregulation. Neither miR-200b nor ZEB1 had obvious effects on CD133 or CD90 expression. Silencing CD13 or CD24 expression suppressed tumorigenicity of HCC cells. Ectopic expression of CD24 reversed the suppression of tumorigenicity by ectopic expression of miR-200b. Clinically, miR-200b downregulation was coupled with ZEB1 upregulation in approximately two-thirds of HCC patients. ZEB1 expression was positively correlated with CD13 and CD24 expressions in HCCs, while miR-200b expression was positively correlated with EpCAM. Our findings suggest that the miR-200b-ZEB1 circuit is a master regulator of diverse stemness of HCC, which differentiates HCCs into those containing CD13 /CD24 CSCs from those containing EpCAM CSCs.

Upregulation of miR-200b Inhibits Hepatocellular Carcinoma Cell Proliferation and Migration by Targeting HMGB3 Protein

“…Here, we demonstrate that miR-200b is downregulated in HCC cells, a finding that is in agreement with previous reports. 21 , 26 In addition, our data show that miR-200b downregulation is significantly associated with shorter overall survival and shorter disease-free survival. A critical role for the aberrant expression of miR-200b in hepatocarcinogenesis is supported by our finding that miR-200b overexpression in HepG 2 cells results in suppression of cell growth and migration, and reduces CD36 expression levels, similar to knockdown of HMGB3.…”

“…These results are in agreement with preceding reports and demonstrate significant downregulation of miR-200b in HCC. 21 , 26 We further analyzed whether there is a correlation between expression of HMGB3 and expression of miR-200b. The HMGB3 RSEM value of 10.825 from TCGA RNA-seq HCC tissues was used as the cutoff point to divide the HCC tissues into low (n = 241) and high (n = 126) HMGB3 expression groups.…”

ELF3 promotes epithelial–mesenchymal transition by protecting ZEB1 from miR-141-3p-mediated silencing in hepatocellular carcinoma

“…Among these transcription factors, we found that ELF3-induced EMT through ZEB1 activation. ZEB1, a member of the ZEB family of transcription factors, has been reported to be overexpressed in several human cancers, including HCC 38 – 40 . Previous studies have shown that ZEB1 directly promotes EMT in HCC.…”

TGF-β as Multifaceted Orchestrator in HCC Progression: Signaling, EMT, Immune Microenvironment, and Novel Therapeutic Perspectives

“…The expression and functions of EMT-TFs are controlled by posttranscriptional regulator miRNAs, which regulate the expression of specific proteins by binding to mRNA transcripts with complementary sequences, destabilizing it. 103 Among the best characterized miRNAs regulating the EMT program, miR-200 family (miR-141, -200a, -200b, -200c, and -429) is well known to be associated with the progression of HCC, 104,105 while miR-205 can directly inhibit EMT by targeting EMT-TFs, ZEB1, and ZEB2 proteins. 106,107 Moreover, miR-200b-ZEB1 circuit has been suggested to function as a master regulator of stemness in HCC.…”

“…106,107 Moreover, miR-200b-ZEB1 circuit has been suggested to function as a master regulator of stemness in HCC. 104 Intriguingly, the miR-200-ZEB1-E-cadherin axis has been demonstrated to be a crucial pathway downstream of TGF-β in the EMT, while reciprocal repression between ZEB1 and the miR-200 family has recently been reported to promote the EMT and invasion in cancer cells. 108,109 Similarly, members of the miR-34 family attenuate the expression of SNAIL.…”