MT2-MMP induces proteolysis and leads to EMT in carcinomas.

Epithelial-mesenchymal transition (EMT) is critical for carcinoma invasiveness and metastasis. To investigate the role of membrane-type-2 matrix metalloproteinase (MT2-MMP) in EMT, we generated lentiviral constructs of wild-type (WT) and an inactive Glu260Ala (E260A) mutant MT2-MMP and derived stably transfected HCT116 and A549 cell lines. WT-transfected cells appeared mesenchymal-like, whereas cells transfected with the E260A mutant were epithelial-like, as were cells treated with an MMP inhibitor (GM6001). Expression of E-cadherin, ß-catenin, and zonula occludens-1 was lower in cells transfected with WT MT2-MMP compared to vector controls, cells treated with GM6001, or cells transfected with the E260A mutant. An 80-kD N-terminal fragment of E-cadherin was immunoprecipitated in conditioned medium from WT MT2-MMP cells, but not in the medium from vector controls, cells treated with GM6001, or E260A mutant cells. When endogenous expression of MT2-MMP in A2780 human ovarian cancer cells was inhibited using GM6001 or MT2-MMP-specific siRNA, levels of the 80-kD E-cadherin fragment in conditioned medium were decreased. Chick embryo chorioallantoic membrane invasion assays demonstrated that cells transfected with WT MT2-MMP were more invasive than cells transfected with control vector, treated with GM6001, or transfected with the E260A mutant. These results suggest that MT2-MMP degrades adherens and tight junction proteins and results in EMT, making it a potential mediator of EMT in carcinomas.

PDGF-D promotes dermal fibroblast invasion in 3-dimensional extracellular matrix via Snail-mediated MT1-MMP upregulation.

Increasing attention has been focused on the malignant tumor microenvironment, which plays important roles in tumor occurrence, progression and metastasis. Fibroblasts are recruited by platelet-derived growth factor (PDGFs) and invade the tumor microenvironment. In the PDGF family, PDGF-B has been reported to play an important role in the recruitment and invasion programs. However, whether PDGF-D plays a role in these programs remains unclear. We generated a recombinant plasmid expressing human PDGF-D and transfected the plasmid to dermal fibroblasts to examine the effects on cell invasive activities in 3D type I collagen gels. PDGF-D plasmid transfection enhanced fibroblast invasive activities both in invasive cell numbers and invasion depth in 3D collagen gels. These effects were blocked by Snail-specific siRNA transfection. PDGF-D transfection significantly induced Snail expression at both mRNA and protein levels. PDGF-D further upregulated MT1-MMP mRNA and protein expressions and this was inhibited when Snail was knocked down by siRNA. Both Snail and MT1-MMP expressions in fibroblasts and cellular invasive activities in 3D collagen induced by PDGF-D were inhibited by LY294002, SP600125, and U1026, the inhibitors of PI3K, JNK, and ERK1/2 signaling pathways, respectively. However, no effects were observed in response to the P38MAPK signaling pathway inhibitor SB203580. These effects of PDGF-D were confirmed by using the culture supernatants of the transfectants. Taken together, these data demonstrate that PDGF-D plays important roles in the recruitment and invasion programs of fibroblasts via the activation of PI3K, JNK and ERK1/2 signaling pathways, and upregulation of Snail and downstream effecter MT1-MMP. These findings indicate that PDGF-D is an important player in the tumor microenvironment for fibroblast recruitment.

Association of TAP1 and TAP2 polymorphisms with the outcome of persistent HBV infection in a northeast Han Chinese population.

OBJECTIVE: Transporter associated with antigen processing (TAP) plays a central role in a cellular immune response against HBV. Polymorphisms exist at the coding region of TAP and alter its structure and function. The aim of this study was to evaluate the potential relationship between polymorphisms of TAP and different outcomes of persistent HBV infection in a Han population in northeastern China. MATERIAL AND METHODS: 189 HBV spontaneously recovered (SR) subjects, 571 HBV-infected patients including 180 chronic hepatitis B (CHB), 196 liver cirrhosis (LC) and 195 hepatocellular carcinoma (HCC) individuals were included in this study. TAP1-333 Ile/Val and -637 Asp/Gly, TAP2-651 Arg/Cys and -687 Stop/Gln were genotyped in all the samples by using a PCR-RFLP method. RESULTS: The frequency of TAP1-637-Gly (allele G) was significantly higher in persistently HBV-infected individuals (CHB and LC) than that of SR subjects (OR = 1.58, 95% CI 1.12-2.45, p = 0.024; OR = 1.78, 95% CI 1.27-2.68, p = 0.002) by a logistic regression analysis. In addition, the statistically significant difference in the distribution of TAP2-651-Cys (allele T) was observed between HCC cases and SR controls (OR = 2.30, 95% CI 1.51-3.72, p < 0.001), and TAP2-687-Gln (allele C) in CHB patients was more common than that in SR subjects (OR = 1.41, 95% CI 1.13-1.97, p = 0.021). The data also revealed that haplotype 687 Gln-651 Cys-637 Gly-333 Ile was strongly associated with persistent HBV infection (CHB, LC and HCC) (p < 0.001, < 0.05 and < 0.001, respectively). CONCLUSION: These results suggested that TAP variants were likely to play a substantial role in different outcomes of persistent HBV infection in the studied population.