Browsing by Author "Akbari, Soheil"

Now showing 1 - 2 of 2

Citation - WoS: 24
Citation - Scopus: 22
Lgr5/R-spo1 Axis Promotes Stemness and Aggressive Phenotype in Hepatoblast-Like Hepatocellular Carcinoma Cell Lines
(Elsevier Science Inc, 2021) Akbari, Soheil; Kunter, Imge; Azbazdar, Yagmur; Ozhan, Gunes; Atabey, Nese; Karagonlar, Zeynep Firtina; Erdal, Esra
Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) is a newly defined stem cell marker in endoderm-derived organs such as the small intestine, colon and pancreas. Recently, LGR5 was demonstrated to be an important factor in liver regeneration and stem cell maintenance. Moreover, LGR5 expression is highly upregulated in various cancers including hepatocellular carcinoma. Herein, we demonstrate that LGR5 expression is specifically observed in certain subset of HCC cell lines with ?hepatoblast-like? appearance, characterized by the expression of liver fetal/progenitor markers. Notably, the activation of the canonical Wnt pathway significantly increases the expression of LGR5 in this subset of cell lines, whereas it does not cause any induction of LGR5 expression in mesenchymal like cell lines SNU-475 and SNU-449. Furthermore, we showed that treatment of the hepatoblast-like HCC cell lines HuH-7 and Hep3B with LGR5 ligand R-Spo1 significantly amplifies the induction of LGR5 expression, the phosphorylation of LRP6 and ?-catenin resulting in enhanced TCF/LEF activity either alone or in combination with Wnt3a. Consistently, the silencing of the LGR5 gene attenuates the co-stimulatory effect of R-Spo1/Wnt3a on TCF/LEF activity while overexpression of LGR5 enhances it. On the contrary, overexpression of LGR5 does not change TCF/LEF activity induced by R-Spo1/Wnt3a in mesenchymal-like HCC line, SNU-449. Importantly, LGR5-overexpressing cells have increased expression of several Wnt target genes and stemness-related genes including EpCAM and CK19 upon R-Spo1/Wnt3a treatment. LGR5-overexpressing cells also have increased spheroid forming, migration and invasion abilities and stimulation with R-Spo1/Wnt3a augments these abilities of LGR5-overexpressing cells. In addition, ectopic overexpression of LGR5 significantly increases cell proliferation rate independent of R-Spo1/Wnt3a stimulation. Moreover, in vitro tubulogenesis assay demonstrates that treatment with R-Spo1/Wnt3a enhances the sprouting of capillary tubules in only LGR5overexpressing cells. Finally, R-Spo1/Wnt3a significantly promotes dissemination of LGR5-overexpressing cells in vivo in a zebrafish xenograft model. Our study unravels a tumor-promoting role for LGR5 through activation of canonical Wnt/?-catenin signaling in the hepatoblast-like HCCs. In conclusion, our results suggest that LGR5/RSpo1/Wnt3a generates an axis that mediates the acquisition of aggressive phenotype specifically in hepatoblastlike subset of HCCs and might represent a valuable target for treatment of HCC tumors with aberrant activation of Wnt/?-catenin pathway.
Citation - WoS: 52
Citation - Scopus: 52
A Novel Function for Klf4 in Modulating the De-Differentiation of Epcam(-)/Cd133(-) Nonstem Cells Into Epcam(+)/Cd133(+) Liver Cancer Stem Cells in Hcc Cell Line Huh7
(Mdpi, 2020) Karagonlar, Zeynep Firtina; Akbari, Soheil; Karabiçici, Mustafa; Sahin, Eren; Avci, Sanem Tercan; Ersoy, Nevin; Ates, Kivilcim Eren
The complex and heterogeneous nature of hepatocellular carcinoma (HCC) hampers the identification of effective therapeutic strategies. Cancer stem cells (CSCs) represent a fraction of cells within tumors with the ability to self-renew and differentiate, and thus significantly contribute to the formation and maintenance of heterogeneous tumor mass. Increasing evidence indicates high plasticity in tumor cells, suggesting that non-CSCs could acquire stem cell properties through de-differentiation or reprogramming processes. In this paper, we reveal KLF4 as a transcription factor that can induce a CSC-like phenotype in non-CSCs through upregulating the EpCAM and E-CAD expression. Our studies indicated that KLF4 could directly bind to the promoter of EpCAM and increase the number of EpCAM(+)/CD133(+) liver cancer stem cells (LCSCs) in the HuH7 HCC cell line. When KLF4 was overexpressed in EpCAM(-)/CD133(-) non-stem cells, the expressions of hepatic stem/progenitor cell genes such as CK19, EpCAM and LGR5 were significantly increased. KLF4 overexpressing non-stem cells exhibited greater cell viability upon sorafenib treatment, while the cell migration and invasion capabilities of these cells were suppressed. Importantly, we detected an increased membranous expression and colocalization of beta -CAT, E-CAD and EpCAM in the KLF4-overexpressing EpCAM(-)/CD133(-) non-stem cells, suggesting that this complex might be required for the cancer stem cell phenotype. Moreover, our in vivo xenograft studies demonstrated that with a KLF4 overexpression, EpCAM(-)/CD133(-) non-stem cells attained an in vivo tumor forming ability comparable to EpCAM(+)/CD133(+) LCSCs, and the tumor specimens from KLF4-overexpressing xenografts had increased levels of both the KLF4 and EpCAM proteins. Additionally, we identified a correlation between the KLF4 and EpCAM protein expressions in human HCC tissues independent of the tumor stage and differentiation status. Collectively, our data suggest a novel function for KLF4 in modulating the de-differentiation of tumor cells and the induction of EpCAM(+)/CD133(+) LCSCs in HuH7 HCC cells.