Establishment and characterization of a spontaneously immortalized myofibroblast cell line derived from a human liver angiosarcoma

In vitro modeling of liver fibrosis with 3D co-culture system using a novel human hepatic stellate cell line

Hepatic stellate cells (HSCs) play an important role in liver fibrosis; however, owing to the heterogeneity and limited supply of primary HSCs, the development of in vitro liver fibrosis models has been impeded. In this study, we established and characterized a novel human HSC line (LSC-1), and applied it to various types of three-dimensional (3D) co-culture systems with differentiated HepaRG cells. Furthermore, we compared LSC-1 with a commercially available HSC line on conventional monolayer culture. LSC-1 exhibited an overall upregulation of the expression of fibrogenic genes along with increased levels of matrix and adhesion proteins, suggesting a myofibroblast-like or transdifferentiated state. However, activated states reverted to a quiescent-like phenotype when cultured in different 3D culture formats with a relatively soft microenvironment. Additionally, LSC-1 exerted an overall positive effect on co-cultured differentiated HepaRG, which significantly increased hepatic functionality upon long-term cultivation compared with that achieved with other HSC line. In 3D spheroid culture, LSC-1 exhibited enhanced responsiveness to transforming growth factor beta 1 exposure that is caused by a different matrix-related protein expression mechanism. Therefore, the LSC-1 line developed in this study provides a reliable candidate model that can be used to address unmet needs, such as development of antifibrotic therapies.

Hepatitis C virus induced miR200c down modulates FAP-1, a negative regulator of Src signaling and promotes hepatic fibrosis

Hepatitis C virus (HCV) induced liver disease is the leading indication for liver transplantation (LTx). Reinfection and accelerated development of fibrosis is a universal phenomenon following LTx. The molecular events that lead to fibrosis following HCV infection still remains poorly defined. In this study, we determined microRNA (miRNA) and mRNA expression profiles in livers from chronic HCV patients and normals using microarrays. Using Genego software and pathway finder we performed an interactive analysis to identify target genes that are modulated by miRNAs. 22 miRNAs were up regulated (>2 fold) and 35 miRNAs were down regulated (>2fold) compared to controls. Liver from HCV patients demonstrated increased expression of 306 genes (>3 fold) and reduced expression of 133 genes (>3 fold). Combinatorial analysis of the networks modulated by the miRNAs identified regulation of the phospholipase C pathway (miR200c, miR20b, and miR31through cellular proto-oncogene tyrosine-protein kinase Src (cSrc)), response to growth factors and hormones (miR141, miR107 and miR200c through peroxisome proliferator-activated receptor alpha and extracellular-signal-regulated kinases, and regulation of cellular proliferation (miR20b, miR10b, and miR141 through cyclin-dependent kinase inhibitor 1 or CDK-interacting protein 1 p21). Real time PCR (RT-PCR) validation of the miRNA in HCV infected livers demonstrated a 3.3 ±0.9 fold increase in miR200c. In vitro transfection of fibroblasts with miR200c resulted in a 2.2 fold reduction in expression of tyrosine-protein phosphatase non-receptor type 13 or FAS associated phosphatase 1 (FAP-1) and 2.3 fold increase in expression of cSrc. miR200c transfection resulted in significant increases in expression of collagen and fibroblast growth factor (2.8 and 3.4 fold, p<0.05). Therefore, we propose that HCV induced increased expression of miR200c can down modulate the expression of FAP1, a critical regulator of Src and MAP kinase pathway that play an important role in the production of fibrogenic growth factors and development of fibrosis.

Paradoxical antiproliferative effect by a murine mammary tumor-derived epithelial cell line

BACKGROUND

Despite significant advancement in breast cancer therapy, there is a great need for a better understanding of the mechanisms involved in breast carcinogenesis and progression, as well as of the role of epigenetic contributions from stromal cells in mammary tumorigenesis. In this study, we isolated and characterized murine mammary tumor-derived epithelial and myofibroblast cell lines, and investigated the in vitro and in vivo effect of cellular soluble factors produced by the epithelial cell line on tumor cells.

METHODS

Morphology, immunophenotype, cytogenetics, invasiveness, and tumorigenicity of epithelial (LM-234ep) and myofibroblast (LM-234mf) cell lines isolated from two murine mammary adenocarcinomas with common ancestor were studied. The in vitro effects of LM-234ep conditioned medium on proliferation, cell cycle distribution, and expression of cell cycle proteins, were investigated in LM-234mf cells, mouse melanoma cells (B16-F10), and human cervical adenocarcinoma cells (HeLa). The in vivo anti-tumor activity of LM-234ep conditioned media was evaluated in subcutaneous tumors formed in nude mice by B16-F10 and HeLa cells.

RESULTS

LM-234ep cells were found to be cytokeratin positive and hipertriploid, whereas LM-234mf cells were alpha-smooth muscle actin positive and hypohexaploid. Chromosome aberrations were found in both cases. Only LM-234mf revealed to be invasive in vitro and to secrete active MMP-2, though neither of the cell types were able to produce progressing tumors. LM-234ep-derived factors were able to inhibit the in vitro growth of LM-234mf, B16-F10, and HeLa cells, inducing cell cycle arrest in G0/G1 phase. The administration of LM-234ep conditioned medium inhibited the growth of B16-F10 and HeLa tumors in nude mice.

CONCLUSION

Our data suggest the existence of epithelial cell variants with tumor suppressive properties within mammary tumors. To our knowledge, this is the first report showing antiproliferative and antineoplastic activities induced by tumor-derived epithelial cells.

The significance of p53 and retinoblastoma pathways in canine hemangiosarcoma

To investigate whether inactivation of the p53 and retinoblastoma (Rb) protein pathways contributes to the development of canine hemangiosarcoma (HSA), we examined immunohistochemically the expression of p53, Rb, phosphorylated Rb (phospho-Rb), p16, and cyclin D1 in 39 spontaneous canine HSAs and 10 hemangiomas. In addition, mutations in the p53 gene were analyzed by polymerase chain reaction (PCR)-single-stranded conformation polymorphism and PCR direct sequencing; furthermore, we quantified cyclin D1 mRNA by semiquantitative real-time reverse transcription-PCR. Positive immunoreactivity for p53 was observed in 17.9% of HSAs. However, mutations were not detected in these cases. The labeling indices for Rb, phospho-Rb, and cyclin D1 were markedly higher in all HSAs than in hemangiomas. Of the 7 cases with cyclin D1-positive immunoreactivity, 4 overexpressed cyclin D1 mRNA (to a level more than 10-fold higher than that of GAPDH mRNA). The p16 protein was clearly detected in all hemangiomas; however, 82% of the neoplastic cells in HSA showed a loss of or low immunoreactivity. These results suggest that alteration of the p16-cyclin D1-Rb pathway, rather than the p53 pathway, may be associated with the pathogenesis of canine HSA.

Tumour suppressor gene p53 mutation in a case of haemangiosarcoma of a dog

Haemangiosarcomas of dogs were analysed by molecular genetic techniques. Regions of the tumour suppressor gene p53, including the well-known tumour hot spots (codons 175, 245, 248, 249, 273 and 282) were screened. A 24 bp deletion was detected in exon 5 of the gene.