HMGB-1 induces cell motility and α5β1 integrin expression in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. High mobility group box chromosomal protein 1 (HMGB)-1 is a widely studied, ubiquitous nuclear protein that is present in eukaryotic cells, and plays a crucial role in inflammatory response. However, the effects of HMGB-1 on human chondrosarcoma cells are largely unknown. In this study, we found that HMGB-1 increased the migration and the expression of α5β1 integrin in human chondrosarcoma cells. Transfection of cells with receptor for advanced glycation end products (RAGE) receptor siRNA reduced HMGB-1-induced cell migration and integrin expression. Activations of phosphatidylinositol 3-kinase (PI3K), Akt, and AP-1 pathways after HMGB-1 treatment were demonstrated, and HMGB-1-induced expression of integrin and migration activity was inhibited by the specific inhibitor and mutant of PI3K, Akt, and AP-1 cascades. Taken together, our results indicated that HMGB-1 enhances the migration of chondrosarcoma cells by increasing α5β1 integrin expression through the RAGE receptor/PI3K/Akt/c-Jun/AP-1 signal transduction pathway.     

Endothelial expression of TNF receptor-1 generates a proapoptotic signal inhibited by integrin α6β1 in glioblastoma

Activation of TNF receptor 1 (TNF-R1) can generate signals that promote either apoptosis or survival. In this study, we show that these signals can be determined by the character of the extracellular matrix in the tumor microenvironment. Specifically, through studies of glioblastoma, we showed that TNFα stimulation induced apoptosis of primary brain endothelial cells (EC) attached to collagen or fibronectin (which engage integrins α2β1/α3β1 and α5β1, respectively), but did not induce apoptosis of ECs attached to laminin (which engages integrins α6β1 and α3β1). TNF-R1 expression was significantly higher in ECs in glioblastoma (GBM) tumors compared with ECs in normal brain specimens. TNFα was also expressed in GBM tumor-associated ECs, which was associated with longer patient survival. ECs plated on anti-integrin α2 or α3 antibody were susceptible to TNFα-induced apoptosis, whereas those plated on anti-integrin α6 antibody were not. Moreover, the ECs plated on laminin, but not collagen, expressed cellular FLICE inhibitory protein (cFLIP) and TNFα stimulation of laminin-attached cells in which cFLIP had been downregulated resulted in the induction of apoptosis. In contrast, attachment to laminin did not induce cFLIP expression in GBM tumor stem cells. Together, our findings indicate that the laminin receptor integrin α6β1 promotes the survival of brain ECs by inhibiting prodeath signaling by TNF-R1, in part by inducing cFLIP expression.     

Endothelial integrin α3β1 stabilizes carbohydrate-mediated tumor/endothelial cell adhesion and induces macromolecular signaling complex formation at the endothelial cell membrane

Blood borne metastatic tumor cell adhesion to endothelial cells constitutes a critical rate-limiting step in hematogenous cancer metastasis. Interactions between cancer associated carbohydrate Thomsen-Friedenreich antigen (TF-Ag) and endothelium-expressed galectin-3 (Gal-3) have been identified as the leading molecular mechanism initiating tumor/endothelial cell adhesion in several types of cancer. However, it is unknown how these rather weak and transient carbohydrate/lectin mediated interactions are stabilized. Here, using Western blot and LC tandem mass spectrometry analyses of pull-downs utilizing TF-Ag loaded gold nanoparticles, we identified Gal-3, endothelial integrin α3β1, Src kinase, as well as 5 additional molecules mapping onto focal adhesion pathway as parts of the macromolecular complexes formed at the endothelial cell membranes downstream of TF-Ag/Gal-3 interactions. In a modified parallel flow chamber assay, inhibiting α3β1 integrin greatly reduced the strength of tumor/endothelial cell interactions without affecting the initial cancer cell adhesion. Further, the macromolecular complex induced by TF-Ag/Gal-3/α3β1 interactions activates Src kinase, p38, and ERK1/2, pathways in endothelial cells in a time- and α3β1-dependent manner. We conclude that, following the initial metastatic cell attachment to endothelial cells mediated by TF-Ag/Gal-3 interactions, endothelial integrin α3β1 stabilizes tumor/endothelial cell adhesion and induces the formation of macromolecular signaling complex activating several major signaling pathways in endothelial cells.     

The expression of TGF-β1, ADAM12 and HB-EGF in primary hepatic carcinoma

Objective: To detect the expression and location of TGF-β1, ADAM12 and HB-EGF in primary hepatic carcinoma and study their effect on the growth and metastasis of hepatoma carcinoma cell. Methods: TGF-β1, ADAM12 and HB-EGF were detected by RT-PCR and immunohistochemistry in 30 cases of hepatic carcinoma tissues, 30 cases of adjacent carci-noma tissues and 5 cases of normal hepatic tissues. Results: RT-PCR analyses showed that the mRNA expression of TGF-β1, ADAM12 and HB-EGF were markedly increased in each hepatic carcinoma tissue compared with its adjacent tissue (P < 0.01), but no signal was detected in normal hepatic tissue, tmmunohistochemistry showed the same outcome on the expression of above three factors in hepatic tissues as RT-PCR. Proteins location analyses showed the proteins of TGF-β1, ADAM12 and HB-EGF all distributed in the stroma of hepatic carcinoma tissues. The positive correlation was found between TGF-β1 and ADAM12 (r=0.6137, P < 0.05), as well as ADAM12 and HB-EGF (r=0.5763, P < 0.05). The protein expression of TGF-β1, ADAM12 and HB-EGF were correlated with the size of tumors, degree of differentiation of hepatoma carcinoma cells, portal vein thrombus and the metastasis of absorbent glands, especially with hepatic cirrhosis caused by hepatitis B virus. Conclu-sion: TGF-β1, ADAM12 and HB-EGF possibly play an important role in the process of growth, invasion and metastasis of hepatoma carcinoma cell, meanwhile, the above three factors may collectively participate in the transition from hepatic cirrhosis caused by hepatitis B virus to hepatocellular carcinoma.     

Immunohistochemical expression of TGF-β1, p21WAF1, p53, Ki67, and angiogenesis in gastric carcinomas

Background: Transforming growth factors-beta (TGF-βs) are multifunctional polypeptides with crucial role as regulators of cellular growth and differentiation. It has been reported that TGF-β1 plays a biphasic action on tumorigenesis thus inducing or inhibiting malignant properties of the epithelial cells. Methods: TGF-β1 expression was analyzed in 56 patients with gastric carcinoma by immunohistochemical methods and compared with the expression of p21, p53, and Ki67, as well as with angiogenesis. The correlation of these markers with clinicopathological parameters was also evaluated. Results: TGF-β1 expression was detected in 71% of tumors and was more frequent in adenocarcinomas of the intestinal type (p<0.001). Positivity of p21WAF1, and p53 was observed in 32% and 51% of the tumors, respectively. A high Ki67 proliferating index was detected in 53.5% of the tumors. TGF-β1 expression was significantly correlated with p21 expression (p<0.001) and was inversely correlated with microvessel density. p21 expression was also higher in tumors with low proliferating index (p<0.01). There was no apparent correlation between the expression of these markers and tumor stage, depth of invasion, or lymphnode metastases. Conclusion: The findings show that TGF-β1 may be involved in the activation of the cdk inhibitor p21WAF1 in gastric adenocarcinomas, suggesting p53-independent induction of p21 in gastric cells. TGF-β1 does not seem to contribute to the alteration of the angiogenic status of these tumors.     

Activation of canonical WNT/β-catenin signaling enhances in vitro motility of glioblastoma cells by activation of ZEB1 and other activators of epithelial-to-mesenchymal transition

Here we show that activation of the canonical WNT/β-catenin pathway increases the expression of stem cell genes and promotes the migratory and invasive capacity of glioblastoma. Modulation of WNT signaling alters the expression of epithelial-to-mesenchymal transition activators, suggesting a role of this process in the regulation of glioma motility. Using immunohistochemistry in patient-derived glioblastoma samples we showed higher numbers of cells with intranuclear signal for β-catenin in the infiltrating edge of tumor compared to central tumor parenchyma. These findings suggest that canonical WNT/β-catenin pathway is a critical regulator of GBM invasion and may represent a potential therapeutic target.     

miR-183 inhibits TGF-β1-induced apoptosis by downregulation of PDCD4 expression in human hepatocellular carcinoma cells

Background  

In recent years, some miRNAs have been reported to be connected closely with the development of human hepatocellular carcinoma. In our previous studies, a set of miRNAs were revealed to be dysregulated in HCC tissues. However, the functions of these miRNAs in HCC remain largely undefined.     

Garcinol,an Acetyltransferase Inhibitor,Suppresses Proliferation of Breast Cancer Cell Line MCF-7 Promoted by 17β-Estradiol

The acetyltransferase inhibitor garcinol, a polyisoprenylated benzophenone, is extracted from the rind of the fruit of Garcinia indica, a plant found extensively in tropical regions. Anti-cancer activity has been suggested but there is no report on its action via inhibiting acetylation against cell proliferation, cell cycle progression, and apoptosis-inhibtion induced by estradiol (E2) in human breast cancer MCF-7 cells. The main purposes of this study were to investigate the effects of the acetyltransferase inhibitor garcinol on cell proliferation, cell cycle progression and apoptosis inhibition in human breast cancer MCF-7 cells treated with estrogen, and to explore the significance of changes in acetylation levels in this process. We used a variety of techniques such as CCK-8 analysis of cell proliferation, FCM analysis of cell cycling and apoptosis, immunofluorescence analysis of NF-κB/p65 localization, and RT-PCR and Western blotting analysis of ac-H3, ac-H4, ac-p65, cyclin D1, Bcl-2 and Bclxl. We found that on treatment with garcinol in MCF-7 cells, E2-induced proliferation was inhibited, cell cycle progression was arrested at G0/G1 phase, and the cell apoptosis rate was increased. Expression of ac-H3, ac-H4 and NF-κB/ac-p65 proteins in E2-treated MCF-7 cells was increased, this being inhibited by garcinol but not ac-H4.The nuclear translocation of NF-κB/p65 in E2-treated MCF-7 cells was also inhibited, along with cyclin D1,Bcl-2 and Bcl-xl in mRNA and protein expression levels. These results suggest that the effect of E2 on promoting proliferation and inhibiting apoptosis is linked to hyperacetylation levels of histones and nonhistone NF-κB/p65 in MCF-7 cells. The acetyltransferase inhibitor garcinol plays an inhibitive role in MCF-7 cell proliferation promoted by E2. Mechanisms are probably associated with decreasing ac-p65 protein expression level in the NF-κB pathway, thus down-regulating the expression of cyclin D1, Bcl-2 and Bcl-xl.