The cancer stem cells and human liver cancer: identifications, expressions and drug resistance

2009/2010This thesis describes several aspects of stem cell theory in human primary liver cancers, both in vivo and in vitro models, with focus on identification, expression and drug resistance related to the CSCs theory..XXIII Cicl

The role of multipotent cancer associated fibroblasts in hepatocarcinogenesis

The presence of tumor supporting cells in various cancer, including in hepatocellular carcinoma (HCC), has become an important target in the study of carcinogenesis. The cancer-associated fibroblast (CAF), one of the most important cellular components in the cancer stroma, might contribute to the progression of the disease due to its plasticity, a behavior of the stem cells. In this study, we investigate the significance of the CAF and its role in the HCC progression and metastasis. Methods: Primary CAF and non-tumoral fibroblast (NTF) from nine paired HCC and distant non-tumoral liver tissues were isolated and cultured. The cells were characterized by flow cytometry, RT-PCR, anchorage-independent assay and in vitro cells directed trans-differentiation. Co-culture study was performed in Transwell system and xenograft assay was performed in immunodeficient mice. Results: CAF and NTF were positive for CD90, CD44, \u3b1SMA, and vimentin and negative for CD34, CD45, CD117, and CD133. When stimulated, they showed the potential to differentiate into adipocytes, osteoblasts, and pancreatic cells. When co-cultured with human HCC cell lines, CAF up-regulated gene expressions of TGFB1 and FAP of HuH-7 and JHH-6 while NTF did not induced either of the genes. Xenograft assay showed that the CAF had the capacity to enter into circulation as confirmed by RT-PCR and DNA sequencing. Conclusion: Our data provides evidence of the plasticity of the CAF and the NTF as stem cells in the process of hepatocarcinogenesis and metastasis. These cells mutually interacts with HCC cells. Their trans-differentiation flexibility may induce a switch from normal to cancerous microenvironment

Serum AP-endonuclease 1 (sAPE1) as novel biomarker for hepatocellular carcinoma

Late diagnosis for Hepatocellular Carcinoma (HCC) remains one of the leading causes for the high mortality rate. The apurinic/apyrimidinic endonuclease 1 (APE1), an essential member of the base excision DNA repair (BER) pathway, contributes to cell response to oxidative stress and has other non-repair activities. In this study, we evaluate the role of serum APE1 (sAPE1) as a new diagnostic biomarker and we investigate the biological role for extracellular APE1 in HCC. sAPE1 level was quantified in 99 HCC patients, 50 non-HCC cirrhotic and 100 healthy controls. The expression level was significantly high in HCC (75.8 [67.3\u201387.9] pg/mL) compared to cirrhosis (29.8 [18.3\u201336.5] pg/mL] and controls (10.8 [7.5\u201313.2] pg/mL) (p < 0.001). The sAPE1 level corresponded with its protein expression in HCC tissue. sAPE1 had high diagnostic accuracy to differentiate HCC from cirrhotic (AUC = 0.87, sensitivity 88%, specificity 71%, cut-off of 36.3 pg/mL) and healthy subjects (AUC 0.98, sensibility 98% and specificity 83%, cut-off of 19.0 pg/mL). Recombinant APE1, exogenously added to JHH6 cells, significantly promotes IL-6 and IL-8 expression, suggesting a role of sAPE1 as a paracrine pro-inflammatory molecule, which may modulate the inflammatory status in cancer microenvironment. We described herein, for the first time to our knowledge, that sAPE1 might be considered as a promising diagnostic biomarker for HCC

MicroRNAs as Regulators of Neo-Angiogenesis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly vascularized neoplasm. In the tumor niche, abundant angiogenesis is fundamental in providing nutrients for tumor growth and represents the first escape route for metastatic cells. Active angiogenesis, together with metastasis, are responsible for the reduction of recurrence-free survival of HCC. MicroRNAs (miRNAs) are small non-coding RNAs that have recently drawn attention in molecular targeted therapy or as diagnostic and prognostic biomarkers. MiRNA expression in HCC has been widely studied in the last decade. Some miRNAs have been found to be up- or down-regulated, besides association with apoptosis, metastasis progression and drug resistance have been found. This review article aims to summarize the angiogenetic process in tumor diseases and to update on what has been found in the vast world of HCC-related-miRNAs and, eventually, to report the latest finding on several miRNAs involved in HCC angiogenesis. We searched the state of the arts for the 12 miRNAs found to be involved with angiogenesis in HCC (miR-29b, miR-126-3p, miR-144-3p, miR-146a, miR-195, miR-199a-3p, miR-210-3p, miR-338- 3p, mir-491, mir-497, mir-638, mir-1301) and reported their main molecular targets and their overall effect in the sprouting of new vessels

Multidrug resistance in hepatic cancer stem cells: the emerging role of miRNAs

There is a fast growing body of evidence that shows several miRNAs are essential to the key features of cancer stem cells (CSC) in hepatocellular carcinoma. However, the function of the miRNAs in different hepatic CSCs and their role in multidrug resistance mechanisms, in particular in those related to the CSC marker ABCG2, is still poorly understood. This limitation is mainly due to the heterogeneity of hepatocellular carcinoma tissues, different CSC markers and high number of deregulated miRNAs, both in primary tumor sites as well as in the circulation. The identification of CSC-related miRNAs and the modulation of hepatocellular carcinoma multidrug resistance would provide a systemic approach in the management of the disease

The multiple origin of cancer stem cells in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) accounts for approximately 6% of all new cancer cases diagnosed, and due to its aggressiveness, it is the second most common cause of cancer mortality worldwide. Based on different etiological factors, genetic backgrounds, and longtime development of the disease, HCC is characterized by a high phenotypic and functional heterogeneity. Tumor variability occurs both among patients (intertumoral heterogeneity) and within a single tumor (intratumoral heterogeneity). The intratumoral heterogeneity, in particular the variability of the markers of cancer stem cells (CSC) population may determine specific behavior and prognosis of the tumor. Understanding the cellular mechanisms originating CSC will provide an important hint in the management of HCC. The characterization of the cells of origin of cancer can have significant implication in early diagnosis, in the development of appropriate therapies and in the prevention of relapse. Here, we review recent evidences on the possible cellular origin of CSC that play a role in the heterogeneity of the HCC

The expression of CD90/Thy-1 in hepatocellular carcinoma: an in vivo and in vitro study.

Although the CD90 (Thy-1) was proposed as biomarker of several tumors and cancer stem cells, the involvement of this molecule in the progression of hepatocellular carcinoma (HCC) and other less frequent hepatic neoplasms is still undefined. The distribution of CD90 was investigated both in in vivo (human tissues samples) and in vitro (human HCC cell line JHH-6). A total of 67 liver tumors were analyzed: 51 HCC, 6 cholangiocarcinoma and 10 hepatoblastoma. In all cases, paired tissue sample of both the tumor and cirrhotic liver was available. Hepatic tissue obtained in 12 healthy livers was used as control. CD90 gene expression was studied by RT-qPCR, protein expression was assessed by quantitative Western Blot, immunofluorescence and flow cytometry. The CD90 expression analysis showed a significant increment in tumor compared to both its paired cirrhotic tissue and normal liver (p<0.05 and p<0.001, respectively). This increase was accompanied by the up-regulation of stromal component in the cancer, as demonstrated by alpha smooth muscle actin staining. In vitro analysis of JHH-6 cell line showed a higher proliferation capacity of CD90(+) compared to CD90(-) cells (p<0.001), also noticed in 3D clonogenic assay (p<0.05), associated by a significant higher expression of the promoting factors (hepatocyte growth factor, fibroblast associated protein and alpha smooth muscle actin 2). A higher expression of the breast cancer resistance protein was found in CD90(+) subpopulation while the multidrug resistance protein 1 showed an opposite behavior. Collectively, these results point to the importance of CD90 in the HCC

The protein analysis of CD90/Thy-1 in primary liver cancers.

<p><b>A</b>. Histological hematoxylin-eosin analysis and CD90 protein distribution in microdissected tissues of normal CTRL (<i>a</i>,<i>d</i>), liver cirrhotic LC of HCC (<i>b</i>,<i>e</i>) and tumoral tissue HCC (<i>c</i>,<i>f</i>). Magnification: objective 20X (<i>a</i>-<i>c</i>), 40x (<i>d</i>-<i>f</i>); CD90-FITC: green, Hoechst 33342: blue. <b>B</b>. Western Blot analysis represented mean ± SD values of CD90 protein expression in LC and tumoral tissues of HCC (n=14), cholangiocarcinoma (CC, n=6), and hepatoblastoma (HB, n=10) compared to normal CTRL (n=6). Protein quantification was performed using densitometric analysis of bands CD90 <i>vs</i>. actin in each sample. Statistical analysis was performed using one-way Anova with Bonferroni post-test (*p<0.05 compared to CTRL). <i>Lower </i><i>right </i><i>panel</i>: representative blot of each paired tissues compared to CTRL. <b>C</b>. The co-expression of CD90 with αSMA in tumoral tissue of HCC. CD90 protein (green), αSMA (red), and nucleus (Hoechst 33342, blue). Arrows indicated CD90⁺SMA^- cells. Magnification: objective 20X.</p

The mRNA expression of CD90/Thy-1 in primary liver cancer by RT-qPCR analysis.

<p><b>A</b>. CD90 distribution in normal liver CTRL (n=12), liver cirrhosis LC of HCC (n=26) and HCC (n=25). Statistical analysis was performed using one-way ANOVA with Bonferroni post-test (*p<0.05, ***p<0.001). Data represented mean ± SD. <b>B</b>. CD90 gene up-regulation in paired individuals of HCC (1-23), cholangiocarcinoma (CC, 24-26), and hepatoblastoma (HB, 27-30). CD90 mRNA relative expression was normalized to reference genes 18SRNA and β-actin; the expression of a normal sample was considered as 1.00 au.</p