TCDD-induced antagonism of MEHP-mediated migration and invasion partly involves aryl hydrocarbon receptor in MCF7 breast cancer cells.

Evidence has shown that the activation of AhR (aryl hydrocarbon receptor) can promote cancer cell metastasis. However, limited studies have been carried out on mixed exposure to endocrine-disrupting chemicals (EDCs), especially in human breast cancer. Therefore, using MCF7 human breast cancer cells, we investigated the effects of coexposure to MEHP (mono 2-ethylhexyl phthalate) and TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) on cell migration and invasion, as well as the roles of AhR and the MMP/slug pathway. Our data suggest that MEHP or TCDD can induce migration and invasion in MCF7 cells, and the promotion is partly AhR dependent. We also observed that MEHP antagonized TCDD to reduce AhR-mediated CYP1A1 expression. Subsequently, we revealed that MEHP recruited AhR to dioxin response element (DRE) sequences and decreased TCDD-induced AhR-DRE binding in CYP1A1 genes. Overall, MEHP is a potential AHR agonist, capable of decreasing TCDD-induced AhR-DRE binding in CYP1A1 genes. The antagonizing effect of coexposure led to the inhibition of the epithelial-mesenchymal transition (EMT) in MCF7 cells. Our study provides new evidence for the potential mechanisms involved in EDCs exposure and their interactions in EMT.

Promoting melanoma growth and metastasis by enhancing VEGF expression.

Angiogenesis plays an essential role in tumor growth and metastasis and is a promising target for cancer therapy. Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. The present study was designed to determine the role of VEGF in tumor growth and metastasis. The sequences for the VEGF gene were cloned into expression plasmids and then transfected into melanoma B16 cells. Overexpression of VEGF transfected with expression plasmids or given exogenous VEGF and epidermal growth factor (EGF) significantly enhanced tumor cell proliferation, migration, and invasion. Tumor growth and metastasis of melanoma B16 cells transfected with VEGF plasmid were significantly promoted compared with those of cells administered with exogenous VEGF or EGF. These results indicated that VEGF can be an effective antiangiogenic strategy for melanoma.

[Pilot study of differentiation of bone marrow derived mesenchymal stem cells into endothelial cells induced by B16 melanoma cells in vitro].

OBJECTIVE: Bone-marrow derived mesenchymal stem cells (BMSC) have the potential to differentiate into endothelial cells. The aim of the study was to investigate the induction process of BMSC by B16 melanoma cells in vitro and to analyze the role of VEGF-a in the process. METHODS: A co-culture system containing BMSC and B16 melanoma cells based on transwell indirect model was established, and the induction process of BMSC by B16 melanoma cells was studied in vitro. RESULTS: BMSC were isolated from the bone marrow of C57 mice. BMSC expressed CD105, CD90, CD73, CD44 and CD166, and acquired expressin of endothelial phenotype markers including VEGFR-1, VEGFR-2 and Factor VIII after co-culture with B16 melanoma cells for 48 hours. The expression level of VEGFR-2 would be double and Factor VIII threefold more by extending the co-culture time to 72 hours. In the co-culture system, B16 melanoma cells also up-regulated the expression of VEGF-a. CONCLUSIONS: VEGF-a plays a significant role in the differentiation of BMSC into cells of endothelial phenotype, therefore, is important to tumor angiogenesis.

Doxycycline inhibits the adhesion and migration of melanoma cells by inhibiting the expression and phosphorylation of focal adhesion kinase (FAK).

Doxycycline has been found to induce apoptosis and to inhibit the growth of a variety of tumor cells, in addition to its use as an antibiotic. However, the mechanism of its actions, especially at the molecular level, remains unknown and needs to be resolved. A crucial step possibly lies in the early period of doxycycline administration, which leads to a series of cascading effects depicting the consequential biological action of doxycycline on tumor cells. The present study focuses on the early-stage effects of doxycycline administration, specifically at the stages of treatment (before 16h). In this paper, we report that doxycycline inhibits the adhesion and migration of melanoma cells. Afterwards, the cells undergo apoptosis (aniokis). Remarkably, doxycycline also inhibits the expression and phosphorylation of focal adhesion kinase (FAK), a protein tyrosine kinase involved in the regulation of cell adhesion and migration. We further demonstrate that doxycycline down-regulates the activities of MMP-2 and MMP-9, and its effects are stronger than those of an Integrin beta1 antibody. Finally, we suggest that doxycycline might exert its anti-tumor effects by inhibiting FAK signaling pathway. These results provide an insight into the possible mechanisms that underlie the multiple drug actions of doxycycline. The potential use of doxycycline in anti-tumor treatment is promising and warrants further studies.

A pilot study on acute inflammation and cancer: a new balance between IFN-gamma and TGF-beta in melanoma.

Recent data have redefined the concept of inflammation as a critical component of tumor progression. However, there has been little development on cases where inflammation on or near a wound and a tumor exist simultaneously. Therefore, this pilot study aims to observe the impact of a wound on a tumor, to build a new mouse tumor model with a manufactured surgical wound representing acute inflammation, and to evaluate the relationship between acute inflammation or wound healing and the process of tumor growth. We focus on the two phases that are present when acute inflammation influences tumor. In the early phase, inhibitory effects are present. The process that produces these effects is the functional reaction of IFN-gamma secretions from a wound inflammation. In the latter phase, the inhibited tumor is made resistant to IFN-gamma through the release of TGF-beta to balance the inflammatory factor effect on the tumor cells. A pair of cytokines IFN-gamma/TGF-beta established a new balance to protect the tumor from the interference effect of the inflammation. The tumor was made resistant to IFN-gamma through the release of TGF-beta to balance the inflammatory effect on the tumor cells. This balance mechanism that occurred in the tumor cells increased proliferation and invasion. In vitro and in vivo experiments have confirmed a new view of clinical surgery that will provide more detailed information on the evaluation of tumors after surgery. This study also provides a better understanding of the relationship between tumor and inflammation, as well as tumor cell attacks on inflammatory factors.

Pilot study on the interaction between B16 melanoma cell-line and bone-marrow derived mesenchymal stem cells.

Bone-marrow derived mesenchymal stem cells (BMSCs) have the potential to differentiate into osteocytes, chondrocytes, adipocytes and endothelial cells. The interaction between BMSCs and epithelial tumor cell was enhanced on proliferation. Our previous study had shown that BMSCs maybe participate in angiogenesis in melanoma in vivo. The aim of this study was to investigate the interaction between B16 melanoma cells and BMSCs in vitro, the mechanism of BMSCs participating in melanoma angiogenesis in vivo is unclear, so a co-culture system containing BMSCs and B16 melanoma cells, based on transwell indirect model, was established, and the interaction between BMSCs and B16 melanoma cells was studied in vitro. In our study, BMSCs were generated out of bone marrow from C57 mouse, isolated BMSCs were positive for the markers CD105, CD90, CD73, CD44 and CD166 and negative for endothelial markers, which acquired endothelial phenotype (including the expression of VEGFR-1, VEGFR-2, Factor VIII) after co-culture with B16 melanoma cells; at the same time, B16 melanoma cells also up-regulated the expression of VEGF-a, VEGFR-1, VEGFR-2 and Factor VIII. The proliferation rate of B16 melanoma cells and BMSCs were also found to be increased. We could show the differentiation of BMSCs into cells with phenotypic features of endothelial cells. BMSCs promoted proliferation of tumor cells and improved the microenvironment in tumor. Our study suggests that the BMSCs may play an important role in tumor angiogenesis.

[Genetic regulatory pathway of gene related breast cancer metastasis: primary study by linear differential model and k-means clustering].

OBJECTIVE: To investigate the potential genetic regulatory pathway of gene related breast cancer metastasis. METHODS: Microarray technique was used to identify the gene expression profile and to screen the differential expression genes in breast cancer with special emphasis on the metastasis factors. A gene chip was available, obtained from the surgical samples, including breast cancer primary tissues and metastasis tissues, of 30 female patients with breast cancer at different clinical stages. Then potential genetic regulatory pathway of gene related breast cancer metastasis was analyzed with a linear differential model and k-means clustering. RESULTS: Twenty-seven differential expression genes were identified. It was suggested that the potential regulatory pathway of gene related to breast cancer metastasis is made up of GRP, BPAG1, and SFRP2 genes. CONCLUSION: The metastasis of breast cancer is related to the cancerization caused by the abnormal expression of multiple genes. It is reliable to analyze the Genetic regulatory pathway of gene related breast cancer metastasis by using multiple bio-informatic measures.