Increased matrix stiffness promotes tumor progression of residual hepatocellular carcinoma after insufficient heat treatment.

Aggravated behaviors of hepatocellular carcinoma (HCC) will occur after inadequate thermal ablation. However, its underlying mechanisms are not fully understood. Here, we assessed whether the increased matrix stiffness after thermal ablation could promote the progression of residual HCC. Heat-treated residual HCC cells were cultured on tailorable 3D gel with different matrix stiffness, simulating the changed physical environment after thermal ablation, and then the mechanical alterations of matrix stiffness on cell phenotypes were explored. Increased stiffness was found to significantly promote the proliferation of the heat-treated residual HCC cells when the cells were cultured on stiffer versus soft supports, which was associated with stiffness-dependent regulation of ERK phosphorylation. Heat-exposed HCC cells cultured on stiffer supports showed enhanced motility. More importantly, vitamin K1 reduced stiffness-dependent residual HCC cell proliferation by inhibiting ERK phosphorylation and suppressed the in vivo tumor growth, which was further enhanced by combining with sorafenib. Increased matrix stiffness promotes the progression of heat-treated residual HCC cells, proposing a new mechanism of an altered biomechanical environment after thermal ablation accelerates HCC development. Vitamin K1 plus sorafenib can reverse this protumor effect.

Angiogenesis enhanced by treatment damage to hepatocellular carcinoma through the release of GDF15.

Transarterial chemoembolization (TACE) is the standard treatment for unresectable hepatocellular carcinoma (HCC). Hypoxia-induced angiogenesis by TACE is linked to treatment failure; however, whether the chemotherapeutic damage of TACE to HCC could increase tumor angiogenesis has not been explored. The molecular effects of chemotherapy-damaged HCC cells on the neo-angiogenesis were investigated in vitro and in vivo. The expression of growth differentiation factor 15 (GDF15) was significantly upregulated in HCC cells exposed to chemotherapeutic agents. GDF15 from chemotherapy-damaged HCC cells promoted the in vitro proliferation, migration, and tube formation of endothelial cells. The pro-angiogenic effect of GDF15 was through the activation of Src and its downstream AKT, MAPK, and NF-κB signaling, which was blocked by thalidomide. The use of thalidomide significantly attenuated the in vivo chemotherapy-damaged HCC cells-promoted angiogenesis in nude mice. In conclusion, the chemotherapeutic damage in TACE to HCC could promote tumor angiogenesis via the increased release of GDF15. Thalidomide could reverse these pro-angiogenic effects.

Identification of oxidative stress-induced gene expression profiles in cavernosal endothelial cells.

The aim of the present study was to explore the regulation status of genes in oxidative stress (OS)­induced endothelial dysfunction and to elucidate the mechanism of action of OS­associated genes, which induce cavernosal endothelial dysfunction in erectile dysfunction (ED). OS was established in purified cavernosal endothelial cells (CECs) using xanthine/xanthine oxidase and the differentially expressed OS­associated genes were analyzed using gene microarrays. In addition, an ED rat model was established through bilateral internal iliac artery ligation with hyperlipidemia and was verified by an intracavernosal pressure test. The selected OS­associated genes were validated in the CECs and ED rat model using reverse transcription­quantitative polymerase chain reaction. Student's t­test and one­way analysis of variance were performed using SBC analysis system. Gene microarray analysis revealed that 13090 (31.92%) genes were expressed in the control group, whereas 12039 (29.35%) genes were expressed in the treated group. The cut­off value for differential expression was set at 2.0 fold­change and 2480 genes were found to be differentially expressed compared with the control group. Of these cells, 1454 were upregulated and 1026 were downregulated. Cluster analysis identified relevant cell signaling pathways that were hypothesized to be significant in OS­associated endothelial dysfunction, including the cytokine­cytokine receptor interactions, nitrogen metabolism, coagulation cascades and cell adherens. Cxcl12, Tgfbr1, Asns, Bdkrb1 and Cdh3 genes showed a corresponding variation in the CECs and ED rat model compared with the results of the gene microarray analysis. In conclusion, in the present study, the network of differentially expressed genes and OS­associated signaling pathways identified using gene microarray analysis were validated in the CECs and ED rat model. The results indicated that OS may lead to endothelial dysfunction through certain cell signaling pathways, inducing ED. However, further functional verification is required in order to elucidate the underlying mechanisms of OS­associated cell signaling pathways in ED.

Rat hepatic stellate cells alter the gene expression profile and promote the growth, migration and invasion of hepatocellular carcinoma cells.

The aim of the present study was to examine the effects of activated hepatic stellate cells (HSCs) and their paracrine secretions, on hepatocellular cancer cell growth and gene expression in vitro and in vivo. Differentially expressed genes in McA-RH7777 hepatocellular carcinoma (HCC) cells following non-contact co-culture with activated stellate cells, were identified by a cDNA microarray. The effect of the co-injection of HCC cells and activated HSCs on tumor size in rats was also investigated. Non-contact co-culture altered the expression of 573 HCC genes by >2-fold of the control levels. Among the six selected genes, ELISA revealed increased protein levels of hepatic growth factor, matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9). Incubation of HCC cells with medium conditioned by activated HSCs significantly increased the proliferation rate (P<0.001), migration rate and the number of invasive HCC cells (P=0.001). Co-injection of HCC cells and activated HSCs into rats significantly increased the weight of the resulting HCC tumors (P<0.01). The paracrine activity of activated HSCs markedly altered the gene expression profile of HCC cells and affected their growth, migration and invasiveness. The results from the present study indicate that the interaction between the activated HSCs and HCC has an important role in the development of HCC.

Dynamic expression patterns of differential proteins during early invasion of hepatocellular carcinoma.

BACKGROUND: Tumor cell invasion into the surrounding matrix has been well documented as an early event of metastasis occurrence. However, the dynamic expression patterns of proteins during early invasion of hepatocellular carcinoma (HCC) are largely unknown. Using a three-dimensional HCC invasion culture model established previously, we investigated the dynamic expression patterns of identified proteins during early invasion of HCC. MATERIALS AND METHODS: Highly metastatic MHCC97H cells and a liver tissue fragment were long-term co-cultured in a rotating wall vessel (RWV) bioreactor to simulate different pathological states of HCC invasion. The established spherical co-cultures were collected on days 0, 5, 10, and 15 for dynamic expression pattern analysis. Significantly different proteins among spheroids at different time points were screened and identified using quantitative proteomics of iTRAQ labeling coupled with LC-MS/MS. Dynamic expression patterns of differential proteins were further categorized by K-means clustering. The expression modes of several differentially expressed proteins were confirmed by Western blot and qRT-PCR. RESULTS: Time course analysis of invasion/metastasis gene expressions (MMP2, MMP7, MMP9, CD44, SPP1, CXCR4, CXCL12, and CDH1) showed remarkable, dynamic alterations during the invasion process of HCC. A total of 1,028 proteins were identified in spherical co-cultures collected at different time points by quantitative proteomics. Among these proteins, 529 common differential proteins related to HCC invasion were clustered into 25 types of expression patterns. Some proteins displayed significant dynamic alterations during the early invasion process of HCC, such as upregulation at the early invasion stage and downregulation at the late invasion stage (e.g., MAPRE1, PHB2, cathepsin D, etc.) or continuous upregulation during the entire invasion process (e.g., vitronectin, Met, clusterin, ICAM1, GSN, etc.). CONCLUSIONS: Dynamic expression patterns of candidate proteins during the early invasion process of HCC facilitate the discovery of new molecular targets for early intervention to prevent HCC invasion and metastasis.

Vascular endothelial cells facilitated HCC invasion and metastasis through the Akt and NF-κB pathways induced by paracrine cytokines.

BACKGROUND: It is well documented that cancer cells secrete angiogenic factors to recruit and sustain tumor vascular networks. However, little is known about the effects of endothelial cells on the behavior of tumor cells. The study here was to determine the roles of endothelial cells in HCC cell growth, migration and invasion. METHODS: A mixture of highly metastatic MHCC97H cells and HUVEC cells, as well as MHCC97H cells alone were subcutaneously injected into nude mice to observe the effects of HUVECs on HCC growth. The biological characteristics of MHCC97H cells respectively treated with conditioned medium (CM) derived from HUVECs and endothelial cell basal medium (EBM) in vitro, such as proliferation, migration and invasion, invasion/metastasis associated gene expression, were comparatively analyzed. Differential cytokines between CM and EBM were screened and identified using human cytokine array. Effects of the interested differential cytokine CCL2, IL-8 and CXCL16 and its related signaling pathways were further investigated in HCC cells. RESULTS: Subcutaneous tumorigenicity of MHCC97H cells in nude mice was promoted by HUVECs and its invasion/metastasis associated genes were significantly upregulated. The in vitro, proliferation, migration and invasion of HCC cells treated with CM were all significantly enhanced as compared to those with EBM stimulation. Simultaneously, PI3K/Akt and ERK1/2 pathway in HCC cells were activated by CM. Total of 25 differential cytokines were identified between CM and EBM such as angiopoietin-2, CCL2 (MCP-1), uPA, endostatin, CXCL16, IL-8, pentraxin 3 etc. The selected differential cytokines CCL2, IL-8 and CXCL16 all modulated the expressions of HCC invasion/metastasis genes, especially MMP2 and MMP9. In exposure to CCL2 or CXCL16 alone, upregulation in AKT phosphorylation but no change in ERK phosphorylation were found in MHCC97H cells, moreover the contents of nuclear transcription factor NF-κB were increased as compared to the control. However, no effects on the activation of Akt and ERK pathway in MHCC97H were found in exposure to IL-8. CONCLUSION: This study expands the contribution of endothelial cells to the progression of HCC. It unveils a new paradigm in which endothelial cells function as initiators of molecular crosstalks that enhance survival, migration and invasion of HCC cells.