lncARSR promotes liver cancer stem cells expansion via STAT3 pathway.

Liver cancer stem cells (CSCs) have important functions in tumorigenesis, progression, recurrence and drug resistance of hepatocellular carcinoma (HCC). lncARSR has been reported to play an important role in the maintenance and self-renewal of renal cancer stem cells, but its role in liver cancer stem cells (CSCs) remains obscure. Herein, we observed high expression of lncARSR in chemoresistant hepatocellular carcinomas (HCCs). A remarkable increase of lncARSR expression in EpCAM or CD133-positive liver CSCs as well as in CSC-enriched hepatoma spheres. Interference lncARSR suppressed liver CSC expansion by inhibiting the dedifferentiation of hepatoma cells and decreasing the self-renewal ability of liver CSCs. Mechanistically, we found STAT3 as the downstream of lncARSR in HCC cells. The special STAT3 inhibitor S3I-201 abolished the discrepancy in liver CSC proportion and the self-renewal capacity between lncARSR knockdown hepatoma cells and control cells, which further confirmed that STAT3 was required in lncARSR promoted liver CSCs expansion. More importantly, interference lncARSR HCC cells were more sensitive to sorafenib or cisplatin treatment. This maybe means that patients with low lncARSR levels benefited from cisplatin or sorafenib treatment, but patients with high lncARSR expression did not. Conclusion: lncARSR was upregulated in liver CSCs and could promote HCC cells dedifferentiation and liver CSCs expansion by targeting STAT3 signaling.

Yang C ，Cai WC ，Dong ZT ，Guo JW ，Zhao YJ ，Sui CJ ，Yang JM ... -  《-》

Long non-coding RNA THOR promotes liver cancer stem cells expansion via β-catenin pathway.

Hepatocellular carcinoma (HCC) is a highly aggressive liver tumor containing cancer stem cells (CSCs), which participate in tumor invasion, therapeutic resistance, and tumor relapse leading to poor outcome and limited therapeutic options. Recently, a novel lncRNA, THOR (testis-associated highly conserved oncogenic long non-coding RNA), was characterized in human cancers and shown to exhibit an oncogenic role. However, the role of THOR in liver cancer stem cells (CSCs) remains obscure. Herein, we observed high expression of THOR in chemoresistant hepatocellular carcinomas (HCCs). A remarkable increase of THOR expression in OV6 or EpCAM-positive liver CSCs as well as in CSC-enriched hepatoma spheres. Interference THOR suppressed liver CSC expansion by inhibiting the dedifferentiation of hepatoma cells and decreasing the self-renewal ability of liver CSCs. Mechanistically, we found β-catenin as the downstream of THOR in HCC cells. The special β-catenin inhibitor FH535 abolished the discrepancy in liver CSC proportion and the self-renewal capacity between THOR knockdown HCC cells and control cells, which further confirmed that β-catenin was required in THOR promoted liver CSCs expansion. Moreover, interference THOR hepatoma cells were more sensitive to sorafenib treatment, indicates that HCC patients with low THOR expression may benefit from sorafenib treatment. Collectively, THOR was upregulated in liver CSCs and could promote HCC cells dedifferentiation and liver CSCs expansion by targeting β-catenin signaling.

Cheng Z ，Lei Z ，Yang P ，Si A ，Xiang D ，Zhou J ，Hüser N ... -  《-》

miR-365 regulates liver cancer stem cells via RAC1 pathway.

Liver cancer stem cells (CSCs) were involved in tumorigenesis, progression, recurrence, and drug resistance of hepatocellular carcinoma (HCC). miR-365 was downregulated in hepatocellular carcinoma and inhibited HCC cell proliferation and invasion. However, the role of miR-365 in liver cancer stem cells was unknown. Herein, we observed a remarkable decrease of miR-365 expression in CD133 or EpCAM-positive liver CSCs as well as in CSC-enriched hepatoma spheres. Up-regulated miR-365 suppressed liver CSC expansion by inhibiting the dedifferentiation of hepatoma cells and decreasing the self-renewal ability of liver CSCs. Mechanistically, bioinformatic and luciferase reporter analysis identified Ras-related C3 botulinum toxin substrate 1 (RAC1) as a direct target of miR-365. Overexpression of miR-365 in hepatoma cells downregulated the RAC1 mRNA and protein expression. RAC1 also could promote the expansion of liver CSCs. The special RAC1 inhibitor EHop-106 or RAC1 overexpression abolished the discrepancy in liver CSC proportion and the self-renewal capacity between miR-365 overexpression hepatoma cells and control cells, which further confirmed that RAC1 was required in miR-365-suppressed liver CSCs expansion. miR-365 was downregulated in liver CSCs and could inhibit HCC cells dedifferentiation and liver CSCs expansion by targeting RAC1 signaling.

Jiang ZB ，Ma BQ ，Liu SG ，Li J ，Yang GM ，Hou YB ，Si RH ，Gao P ，Yan HT ... -  《-》

miR-194 inhibits liver cancer stem cell expansion by regulating RAC1 pathway.

Liver cancer stem cells (CSCs) contribute to tumorigenesis, progression, drug resistance and recurrence of hepatocellular carcinoma (HCC). However, the underlying mechanism for the propagation of liver CSCs remains unclear. Herein, we observed low expression of miR-194 in chemoresistant HCC cells. A remarkable decrease of miR-194 was detected in EpCAM or CD133-positive liver CSCs and CSC-enriched hepatoma spheres. Interference miR-194 facilitated liver CSCs expansion by enhancing the self-renewal of liver CSCs. While up-regulating miR-194 inhibited liver CSCs expansion by suppressing the self-renewal of liver CSCs. Furthermore, hepatoma cells with miR-194 overexpression performed more sensitivity to sorafenib treatment. Mechanistically, functional studies found that Ras-related C3 botulinum toxin substrate 1 (RAC1) was a direct target of miR-194. Overexpression of miR-194 inhibited the expression of RAC1 in liver CSCs. Special RAC1 siRNA diminished the discrepancy in liver CSC proportion and the self-renewal capacity between miR-194 overexpression hepatoma cells and control cells, which further confirmed that RAC1 was required in miR-194-inhibited liver CSCs expansion. More importantly, downregulated expression of miR-194 was a predictor of poor prognosis of HCC patients.

Ran RZ ，Chen J ，Cui LJ ，Lin XL ，Fan MM ，Cong ZZ ，Zhang H ，Tan WF ，Zhang GQ ，Zhang YJ ... -  《-》

miR-613 inhibits liver cancer stem cell expansion by regulating SOX9 pathway.

Liver cancer stem cells (CSCs) contribute to tumorigenesis, progression, drug resistance and recurrence of hepatocellular carcinoma (HCC). However, the underlying mechanism for the propagation of liver CSCs remains unclear. Herein, we observed miR-613 expression was downregulated in both chemoresistant and recurrent HCC patients. A remarkable decrease in miR-613 was detected in CD24 or OV6-positive liver CSCs and CSC-enriched hepatoma spheres. Down-regulation of miR-613 facilitated liver CSCs expansion by promoting the dedifferentiation of hepatoma cells and enhancing the self-renewal of liver CSCs. Mechanistically, bioinformatic and luciferase reporter analysis identified SOX9 as a direct target of miR-613. Overexpression of miR-613 inhibited the expression of SOX9 in HCC cells. Special SOX9 siRNA abolished the discrepancy in liver CSCs proportion and the self-renewal capacity between miR-613 overexpression hepatoma cells and control cells, which further confirmed that SOX9 was required in miR-613-inhibited liver CSCs expansion. Furthermore, hepatoma cells with miR-613 overexpression performed more sensitivity to cisplatin or sorafenib treatment. Conclusion: miR-613 could inhibit HCC cell dedifferentiation and liver CSCs expansion by targeting SOX9 signaling and may prove to be a novel therapeutic target for HCC patients.

Li B ，Liu D ，Yang P ，Li HY ，Wang D ... -  《-》