CXCR4/TGF-ß1 mediated self-differentiation of human mesenchymal stem cells to carcinoma-associated fibroblasts and promoted colorectal carcinoma development.

Background: Tumor microenvironment (TME) is a crucial part of tumor hallmarks. Mesenchymal stem cells (MSCs), important components of TME, are the main source of Carcinoma-associated fibroblasts (CAFs), but the mechanism of transformation regulation is still unclear. Transforming growth factor-ß1 (TGF-ß1), chemokine Stromal cell-derived factor-1 (SDF-1) and its endogenous receptor CXCR4 may play important roles during this process.Methods: Co-culture technique was used to explore the effects of MSCs on the proliferation, migration and invasion of colorectal carcinoma (CRC) cells and how they induced MSCs to differentiate into CAFs. The expression of α-SMA, Vimentin, S100A4 and FAP were detected as CAFs markers. Inhibitors AMD3100 and cyclophosphamide (Cy) were pre-treated in MSCs to verify the functions of CXCR4/TGF-ß1. Finally, the xenograft models in nude mice were generated to further verify this process in vivo.Results: MSCs promoted the CRCs proliferation, invasion and migration, and induced SDF-1 expression and secretion, which dramatically up-regulated CXCR4 and TGF-ß1 expression in MSCs. The levels of CAFs markers elevated in MSCs, indicating CAFs differentiation occurred in MSCs. AMD3100 and Cy treatment significantly blocked this differentiation process of MSCs by suppressing CXCR4 expression and TGF-ß1 secretion. In vivo xenograft experiments also demonstrated that MSCs promoted differentiation into CAFs through CXCR4/TGF-ß1 signaling in either primary tumor tissues or hepatic metastatic tissues of CRC.Conclusion: Our studies have revealed the essential role of CXCR4/TGF-ß1 axis playing in the transformation of tumor microenvironment by mediating MSCs differentiation into CAFs, promoting CRCs growth and metastasis.

CXCR4/TGF-ß1 mediated hepatic stellate cells differentiation into carcinoma-associated fibroblasts and promoted liver metastasis of colon cancer.

Background: Liver metastasis of colon cancer is strongly affected by the tumor microenvironment (TME), with interactions between tumor cells and cancer-associated fibroblasts (CAFs) in particular. TGF-ß is well known for its ability to mediate the CAF phenotype, and CXCR4 expression is closely correlated to poor prognosis in CRC. The relationship between these two signaling pathways remains to be delineated in liver metastasis of colon cancer.Methods: Immunohistochemistry was employed to investigate CXCR4 expression in 45 human specimens of primary colorectal cancer (CRC) and liver metastasis. The functions of SDF-1 released by hepatic stellate cells (HSCs) on CXCR4 and TGF-ß1 in CRC cells were investigated in vitro. The effects of CRC on HSCs differentiation into CAFs were confirmed using co-culture technology and expression analysis of CAFs markers by qPCR, western blot and immunofluorescence. The involvement of CXCR4 and TGF-ß1 was verified with addition of CXCR4 inhibitor AMD3100 and TGF-ß1 inhibitor cyclophosphamide (Cy) both in vitro and in vivo.Results: There were more CXCR4-positive cells at the liver metastatic tissues compared to the primary sites. CRC cells activated and transformed HSCs to CAFs after co-cultivating with HSCs. Activated HSCs stimulated TGF-ß1 secretion from CRC cells after co-culture with CRC cells in vitro. Moreover, the expression of CAFs markers was increasing in the activated HSCs. In a mouse hepatic metastasis model, treated with AMD3100 or Cy blocked the metastatic potential of HCT116 cells and the hepatic CAFs differentiation.Conclusions: These results indicated that CXCR4/TGF-ß1 axis plays an important role in CRC liver metastasis through mediating HSCs differentiation into CAFs, providing preclinical evidences that blockade of the axis might be beneficial for anti-metastasis therapy in CRC.

TGFß1 is essential for MSCs-CAFs differentiation and promotes HCT116 cells migration and invasion via JAK/STAT3 signaling.

BACKGROUND AND PURPOSE: Colorectal cancer (CRC) frequently metastasizes to the liver, which involves the participation of multiple cytokines. Tumor microenvironment (TME) composed of cancer-associated fibroblasts (CAFs) and tumor cells acts as an essential factor in cancer metastasis. Transforming growth factor ß1 (TGFß1) is a vital cytokine involved in migration and invasion of cancer cells. However, the underlying mechanisms remain unclear. In the present study, we aimed to investigate the role and molecular mechanisms of TGFß1 in TME. METHODS: The conditioned medium prepared from colorectal cancer HCT116 and HT29 cells was used to culture mesenchymal stem cells (MSCs). The differentiation of MSCs to CAFs was detected by flow cytometry. The role of TGFß1 in colorectal cancer cells metastasis was examined by wound-healing assay and transwell assay. And the activation of the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) signaling pathway was measured by Western blot assay. RESULTS: TGFß1 induced the differentiation of MSCs to CAFs and improved HCT116 and HT29 cells migration and invasion. Meanwhile, TGFß1 also upregulated the phosphorylation of STAT3 and enhanced the nuclear localization of p-STAT3, which activated JAK/STAT3 signaling pathway. CONCLUSION: TGFß1 induced the differentiation of MSCs into CAFs and promoted the migration and invasion of HCT116 and HT29 cells, which depended on the activation of JAK/STAT3 signaling pathway.

FAK is involved in invasion and metastasis of hepatocellular carcinoma.

Studies have shown that focal adhesion kinase (FAK) is overexpressed in several human tumors and plays an important role in tumor progression. However, the role and underlying mechanisms of FAK in hepatocellular carcinoma (HCC) progression remains to be elucidated. In this study, we examined FAK and phosphorylated FAK Tyr397 expression in a large series of HCCs. We found that both FAK and phosphorylated FAK Tyr397 were overexpressed in HCC samples and HCC cell lines. Increased FAK and phosphorylated FAK Tyr397 expressions were correlated with tumor stage, vascular invasion and intrahepatic metastasis in HCC. Furthermore, HCC cell adhesion, migration and invasion were substantially impaired by siRNA-mediated knockdown of FAK expression, whereas cell growth, apoptosis and cell cycle distribution were not affected. In addition, depletion of FAK induced a significant reduction in expressions and activities of both MMP-2 and MMP-9. Taken together, FAK contributes to invasion and metastasis of HCC partly through regulating expressions and activations of both MMP-2 and MMP-9, suggesting FAK could be a promising therapeutic target for HCC.

MicroRNA-9 reduces cell invasion and E-cadherin secretion in SK-Hep-1 cell.

MicroRNAs (miRNAs) are an abundant class of short noncoding RNAs that can posttranscriptionally regulate gene expression in animals. They are also involved in cancer initiation and progression, and their expression profiles serve as phenotypic signatures of different cancers. The roles played by microRNAs specifically in "micromanagement of metastasis" has been addressed only recently. The molecular mechanisms of hepatocellular carcinoma (HCC) metastasis are still poorly understood. Recent evidence implies genetic determinants of cancer metastasis. Because gene expression signature significantly differs between primary metastasis-free HCC and primary HCC with intrahepatic metastases, miRNA expression in those primary HCC may change correspondingly. The 28 up-regulated miRNAs, part of the reported miRNA profiles of HCC, were compared in primary HCC with or without metastases. Only eight miRNAs were found to be significantly up-regulated in primary HCC with metastases while miR-9 had the highest hold change. miR-9 was highly expressed in SK-Hep-1 cell when compared with other hepatoma cell lines and downregulation of miR-9 reduced SK-Hep-1 cell invasion. E-cadherin, a tumor invasion suppressor in HCC, was found to be a putative gene target of miR-9. E-cadherin was up-regulated by miR-9 inhibitor. The findings suggest miR-9 could be involved in HCC metastasis.

Bead-based microarray analysis of microRNA expression in hepatocellular carcinoma: miR-338 is downregulated.

AIM: Recent studies have underlined causative links between microRNA (miRNA) deregulation and cancer development. However, the relevance of abnormally expressed miRNA to tumor biology has not been well understood in hepatocellular carcinoma (HCC). METHODS: A bead-based miRNA expression profiling method was performed on 20 pairs of surgically removed HCC and adjacent non-tumorous tissue (NT). Special miR-338 downregulations and miR-338 associated with clinical characteristics was validated in an extended samples set of 36 paired HCC and adjacent non-tumorous liver tissues by real-time reverse transcription polymerase chain reaction (RT-PCR) analysis. RESULTS: Out of our bead-based microarray data, 12 upregulated and 19 downregulated miRNA were found to be associated with HCC. Further characterization of miRNA-338, in which 20 pairs of the samples were clustered clearly into two groups according to expression of miR-338, revealed that the level of miR-338 expression can be associated with clinical aggressiveness, such as, tumor size, tumor-node-metastasis stage, vascular invasion and intrahepatic metastasis. These results were validated by real-time RT-PCR analysis. CONCLUSION: Our study suggests that miRNA expression could have relevance to the clinical behavior of HCC and that the bead-based miRNA expression profiling method might be a suitable system to assay miRNA expression in large-scale diagnostic trails.

Involvement of PI3K/PTEN/AKT/mTOR pathway in invasion and metastasis in hepatocellular carcinoma: Association with MMP-9.

AIM: To investigate the status of Phosphatidylinositol 3-kinase (PI3K)/PTEN/AKT/mammalian target of rapamycin (mTOR) pathway and its correlation with clinicopathological features and matrix metalloproteinase-2, -9 (MMP-2, 9) in human hepatocellular carcinoma (HCC). METHODS: PTEN, Phosphorylated AKT (p-AKT), Phosphorylated mTOR (p-mTOR), MMP-2, MMP-9 and Ki-67 expression levels were evaluated by immunohistochemistry on tissue microarrays containing 200 HCCs with paired adjacent non-cancerous liver tissues. PTEN, MMP-2 and MMP-9 mRNA levels were determined by real-time RT-PCR in 36 HCCs. The relationships between PI3K/PTEN/AKT/mTOR pathway and clinicopathological factors and MMP-2, 9 were analyzed in HCC. RESULTS: In HCC, PTEN loss and overexpression of p-AKT and p-mTOR were associated with tumor grade, intrahepatic metastasis, vascular invasion, TNM stage and high Ki-67 labeling index (P < 0.05). PTEN loss was correlated with p-AKT, p-mTOR and MMP-9 overexpression. Furthermore, PTEN and MMP-2, 9 mRNA levels were down-regulated and up-regulated in HCC compared with paired non-cancerous liver tissues, respectively (P < 0.01). PTEN, MMP-2 and MMP-9 mRNA levels were correlated with tumor stage and metastasis. There was an inverse correlation between PTEN and MMP-9 mRNA expression. However, PI3K/PTEN/AKT/mTOR pathway was not correlated with MMP-2. CONCLUSIONS: PI3K/PTEN/AKT/mTOR pathway, which is activated in HCC, is involved in invasion and metastasis through up-regulating MMP-9 in HCC.

[Epigallocatechin-3-gallate induces apoptosis in human hepatocellular carcinoma cells].

OBJECTIVE: To investigate the effects of epigallocatechin-3-gallate (EGCG) on human hepatocellular carcinoma (HCC) cells and mechanism thereof. METHOD: Human HCC cells of the lines HepG2 and SMMC-7721 were cultured and treated with of EGCG of the concentrations of 6.25, 12.5, 25, 50, 100, 200, and 400 microg/ml respectively for 24 h and 48 h. The cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Trypan blue staining was used to count the cells. Flow cytometry was conducted to detect the cell apoptosis. The protein levels of Bcl-2, an anti-apoptosis factor, and cyclooxygenase-2 (COX-2), an up-regulator of Bcl-2. The activities of caspase-9 and caspase-3 hat promote the apoptosis of HCC cells, were measured using colorimetric method. RT-PCR was used to detect the mRNA expression of COX-2 and Bcl-2 family. RESULTS: The viabilities of the HepG2 and SMMC-7721 cells treated with EGCG of the concentrations of 50 - 400 microg/ml for 48 h reduced to 93.8% +/- 2.8%, 62.3% +/- 5.4%, 33.9% +/- 2.5%, and 17.6% +/- 3.2% respectively, all significantly lower than that of the control group [(100.0% +/- 2.8%), all P < 0.05]; and the viabilities of the SMMC-772 cells treated with EGCG of the concentrations of 50 - 400 microg/ml for 48 h reduced to 49.6% +/- 3.5%, 30.3% +/- 3.8%, 17.7% +/- 2.2%, and 13.0% +/- 2.5% respectively, all significantly lower than that of the control group [(100.0% +/- 0.8%), all P < 0.05]. After treatment with 100 microg/ml EGCG for 24 h, 48 h, 72 h, and 96 h, the live HepG2 cell numbers were (8.0 +/- 1.5), (22.0 +/- 3.1), (37.0 +/- 5.4), and (61.0 +/- 8.7) 10(4) respectively, all significantly lower than those of the control cells [(15.0 +/- 2.5), (45.0 +/- 5.3), (86.0 +/- 11.0), and (210.0 +/- 23.0) 10(4) respectively, all P < 0.05]; and the live SMMC-7721 cell numbers were (7.0 +/- 2.2), (13.0 +/- 2.5), (20.0 +/- 3.7), and (31.0 +/- 4.0) 10(4) respectively, all significantly lower than those of the control cells [(15.0 +/- 2.5), (45.0 +/- 5.3), (86.0 +/- 11.0), and (210.0 +/- 23.0) 10(4) respectively, all P < 0.05]. The apoptotic rates of HepG2 cells treated with EGCG of the concentrations of 50, 100, and 200 microg/ml for 12 h were 8.7% +/- 0.4%, 18.1% +/- 1.1%, and 22.1% +/- 1.8% respectively, all significantly higher than that of the control group (3.3% +/- 0.3%, P < 0.05); and the apoptotic rates of SMMC-7721 cells were 5.9% +/- 0.3%, 7.8% +/- 0.6%, and 12.2% +/- 0.8% respectively, all significantly higher than that of the control group (3.7% +/- 0.4%, P < 0.05). After treatment with EGCG of the concentrations of 100 and 200 microg/ml for 12 h, the caspase-9 activities of the HepG2 cells increased to (1.8 +/- 0.4) and (2.5 +/- 0.4) respectively, both significantly higher than that of the control group (1.0 +/- 0.1, both P < 0.05); and the caspase-3 activities of the HepG2 cells increased to (2.0 +/- 0.4) and (2.8 +/- 0.5) respectively, both significantly higher than that of the control group (1.0 +/- 0.2, P < 0.05) ; and the caspase-9 activities of the SMMC-7721 cells increased to (1.7 +/- 0.4) and (2.5 +/- 0.4), both significantly higher than that of the control group (1.0 +/- 0.1, both P < 0.05), and the caspase-3 activities of the SMMC-7721 cells increased to (1.9 +/- 0.4) and (2.6 +/- 0.3) respectively, both significantly higher than that of the control group [ (1.0 +/- 0.2), both P < 0.05]. When the concentration of EGCG was over 200microg/ml, it down-regulated the expression of COX-2 and Bcl-2 in both cell lines, however, EGCG resulted in no significant changes of Bcl-xl, Bax, Bad, and Bid. CONCLUSION: EGCG induces apoptosis in HCC cells through down-regulation of COX-2 and Bcl-2 and consequently activating caspase-9 and caspase-3.

[Effect of recipient derived bone marrow stromal cells on immunological rejection in mouse allogeneic skin transplantation].

OBJECTIVE: To investigate the effect of recipient derived bone marrow stromal cells (BMSCs) on immunological rejection in mouse allogeneic skin transplantation. METHODS: The C57BL/6 to BALB/c allogeneic skin transplantation model was created. The bone marrow stromal cells (BMSCs) were isolated from BALB/c by gradient density centrifugation and adhesion separation. The BMSCs were injected back through tail vein. The mouse were divided into three groups as group A (BALB/c + BMSCs), group B (BALB/c with skin transplantation), and group C (BALB/c with skin transplantation + BMSCs). The pathologic examination of the graft was performed and the cytokines such as IL-2, IFN-gamma were detected at the different time. RESULTS: The attained BMSCs in the experiment had the characteristics of BMSCs. The acute immunological rejection reaction detected by immunohistochemistry staining was alleviated noticeably in group C than that in group B. The concentrations of cytokines IL-2, IFN-gamma in group B were lower than that in group C at 7 d (F = 248,954.6, P < 0.05; F = 148,311.7, P < 0.05) and 14 d (F = 117,372.3, P < 0.05; F = 126,743.3, P < 0.05) after skin transplantation. CONCLUSIONS: Recipient derived BMSCs transfusion can alleviate the acute immunological rejection after allogeneic skin transplantation. The possible mechanism maybe related to the inhibitory effect on the secretion of cytokines like IL-2, IFN-gamma.