7980

TFPI2

tissue factor pathway inhibitor 2;TFPI2;tissue factor pathway inhibitor 2

placental protein 5|retinal pigment epithelium cell factor 1

7q22

protein-coding

LINE-1 retrotransposons are abundant repetitive elements of viral origin, which in normal cells are kept quiescent through epigenetic mechanisms. Activation of LINE-1 occurs frequently in cancer and can enable LINE-1 mobilization but also has retrotransposition-independent consequences. We previously reported that in cancer, aberrantly active LINE-1 promoters can drive transcription of flanking unique sequences giving rise to LINE-1 chimeric transcripts (LCTs). Here, we show that one such LCT, LCT13, is a large transcript (>300 kb) running antisense to the metastasis-suppressor gene TFPI-2. We have modelled antisense RNA expression at TFPI-2 in transgenic mouse embryonic stem (ES) cells and demonstrate that antisense RNA induces silencing and deposition of repressive histone modifications implying a causal link. Consistent with this, LCT13 expression in breast and colon cancer cell lines is associated with silencing and repressive chromatin at TFPI-2. Furthermore, we detected LCT13 transcripts in 56% of colorectal tumours exhibiting reduced TFPI-2 expression. Our findings implicate activation of LINE-1 elements in subsequent epigenetic remodelling of surrounding genes, thus hinting a novel retrotransposition-independent role for LINE-1 elements in malignancy.

We examined whether TFPI2 methylation can be used as a molecular marker for colorectal cancers by detecting TFPI2 methylation in colorectal cancer patients' sera by using quantitative methylation-specific polymerase chain reaction (qMSP). The qMSP analysis showed that 39 of 215 (18%) patients exhibited TFPI2 methylation in their serum DNA, suggesting that TFPI2 methylation frequently existed in colorectal cancer patients' sera. After completion of qMSP analysis, clinicopathological data were correlated with molecular data. TFPI2 methylation was significant in the sera of patients with large (p = 0.0022), poorly differentiated carcinoma (p = 0.0164), deep invasion (p = 0.0002), lymph node metastasis (p = 0.0147), or distant metastasis (p < 0.0001). Moreover, TFPI2 methylation was observed more frequently according to the progression of TNM stage, suggesting that serum TFPI2 methylation could be detected more easily in patients with advanced colorectal cancer. We also examined whether serum TFPI2 methylation would be useful in the detection of colorectal cancer, compared to the conventional tumor markers. Detection rates of colorectal cancer using the tumor markers TFPI2 methylation, CEA and CA19-9, in the serum were 18%, 33%, and 17%, respectively. In cases where we combined all three markers, the detection rate was 42%. High sensitivity of qMSP enables detection of smaller amounts of serum tumor DNA. In principle, the methylation status of a primary tumor is not required in advance to detect circulating tumor DNA, suggesting the potential of qMSP as a cancer screening method.

LINE-1 retrotransposons are abundant repetitive elements of viral origin, which in normal cells are kept quiescent through epigenetic mechanisms. Activation of LINE-1 occurs frequently in cancer and can enable LINE-1 mobilization but also has retrotransposition-independent consequences. We previously reported that in cancer, aberrantly active LINE-1 promoters can drive transcription of flanking unique sequences giving rise to LINE-1 chimeric transcripts (LCTs). Here, we show that one such LCT, LCT13, is a large transcript (>300 kb) running antisense to the metastasis-suppressor gene TFPI-2. We have modelled antisense RNA expression at TFPI-2 in transgenic mouse embryonic stem (ES) cells and demonstrate that antisense RNA induces silencing and deposition of repressive histone modifications implying a causal link. Consistent with this, LCT13 expression in breast and colon cancer cell lines is associated with silencing and repressive chromatin at TFPI-2. Furthermore, we detected LCT13 transcripts in 56% of colorectal tumours exhibiting reduced TFPI-2 expression. Our findings implicate activation of LINE-1 elements in subsequent epigenetic remodelling of surrounding genes, thus hinting a novel retrotransposition-independent role for LINE-1 elements in malignancy.

Human tissue factor pathway inhibitor-2 (TFPI-2) is a matrix-associated Kunitz inhibitor that inhibits the plasmin- and trypsin-mediated activation of zymogen matrix metalloproteinases involved in tumor progression, invasion, and metastasis. To directly assess its role in tumor growth and metastasis in vivo, we stably transfected HT-1080 fibrosarcoma cells expressing either fully active wild-type human TFPI-2 (WT) or inactive R24Q TFPI-2 (QT) and examined their ability to form tumors and metastasize in athymic mice in comparison to mock-transfected cells (MT). MT and QT fibrosarcoma tumors grew 2 to 3 times larger than WT tumors. tumor metastasis was confined to the lung and was observed in 75% of mice treated with either MT or QT cells, whereas only 42% of mice treated with WT cells developed lung metastases. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analyses of each tumor group revealed 3- to 6-fold lower levels of murine vascular endothelial growth factor gene expression in WT tumors in relation to either MT or QT tumors. Comparative tumor gene expression analysis revealed that several human genes implicated in oncogenesis, invasion, metastasis, apoptosis, and angiogenesis had significantly altered levels of expression in WT tumors. Our collective data demonstrate that secretion of inhibitory TFPI-2 by a highly metastatic tumor cell markedly inhibits its growth and metastasis in vivo by regulating pericellular extracellular matrix (ECM) remodeling and angiogenesis.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death in the world and metastasis is an essential aspect of HCC progression. Tissue factor pathway inhibitor-2 (TFPI-2) has been implicated as a potential suppressor gene to regulate tumor invasion and metastasis. In this study, we silenced TFPI-2 in the HCC cell line MHCC97-L and evaluated the role of TFPI-2 in cell invasion and its impact on gene expression. We showed in this study that stable TFPI-2 downregulation in MHCC97-L cells resulted in increased cell adhesion and invasion. We also showed that mRNA and protein expression levels of MMP-1/3, CD44, and ICAM-1 were increased, while those of MMP-2/9 were not changed by TFPI-2 silencing. Furthermore, silencing of TFPI-2 caused increased Akt phosphorylation level and NF-kappaB transcription in MHCC97-L cells. In conclusion, this study confirms that TFPI-2 downregulation can contribute to tumor invasion of HCC cells through alteration in the expression of metastasis-related genes.

To identify tumor-suppressor genes inactivated by aberrant methylation of promoter CpG islands (CGIs) in human malignant melanomas, genes upregulated by treatment of cells with a demethylating agent, 5-aza-2'-deoxycytidine (5-aza-dC), were searched for using oligonucleotide microarrays in melanoma cell lines, HMV-I, MeWo and WM-115. Seventy-nine known genes with CGIs were identified as being upregulated (>or=16-fold), and 18 of them had methylation of their putative promoter CGIs in 1 or more of 8 melanoma cell lines. Among the 18 genes, TFPI-2, which is involved in repression of the invasive potential of malignant melanomas, was further analyzed. Its expression was repressed in a melanoma cell line with its complete methylation, and was restored by 5-aza-dC treatment. It was unmethylated in cultured neonatal normal epidermal melanocyte, and was induced by ultraviolet B. In surgical melanoma specimens, TFPI-2 methylation was detected in 5 of 17 metastatic site specimens (29%), while it was not detected in 20 primary site specimens (0%) (p=0.009). By immunohistochemistry, the 5 specimens with promoter methylation lacked immunoreactivity for TFPI-2. The results showed that TFPI-2 is silenced in human malignant melanomas by methylation of its promoter CGI and suggested that its silencing is involved in melanoma metastasis.

OBJECTIVE: Extracellular matrix (ECM) remodeling during angiogenesis is accomplished through plasmin-dependent pericellular proteolysis and through the action of matrix metalloproteinases (MMPs). Because tissue factor pathway inhibitor-2 (TFPI-2), a Kunitz-type protease inhibitor with prominent ECM localization, inhibits plasmin and MMPs activity, we investigated the role of TFPI-2 in endothelial cell (EC) migration and angiogenesis. METHODS AND RESULTS: Real-time polymerase chain reaction and immunostaining showed that the expression of TFPI-2 mRNA and protein was upregulated in migrating ECs. The effect of TFPI-2 on angiogenesis was studied in mouse models of Matrigel and polyvinylalcohol sponge implants by overexpressing TFPI-2 through infection with a replication-deficient adenovirus (AdTFPI-2). Using (immuno)fluorescence and confocal microscopy we observed that TFPI-2 reduced neovascularization and promoted ECM deposition. Lateral cell migration and capillary tube formation in vitro also were impaired by TFPI-2, a process reversed by anti-TFPI-2 antibodies. Increased apoptosis occurred both in AdTFPI-2-treated ECs and in the mouse implants. Zymography and assays in the absence of plasminogen confirmed plasmin inhibition as a main mechanism through which TFPI-2 inhibits EC migration. CONCLUSIONS: Our data suggest that TFPI-2 may be an important regulator of aberrant angiogenesis associated with tumor growth/metastasis, cardiovascular diseases, chronic inflammation, or diabetes.

Tissue factor pathway inhibitor-2 (TFPI-2) is a matrix-associated kunitz-type serine proteinase inhibitor that plays an important role in plasmin and trypsin-mediated activation of zymogen matrix metalloproteinases involved in tumor angiogenesis, invasion and metastasis. Earlier studies have shown that the production of TFPI-2 is downregulated during the progression of various tumors. To detect whether TFPI-2 can be expressed in human pancreatic carcinoma samples, to evaluate its prognostic significance on pancreatic carcinoma and to investigate its effect on tumor invasion and metastasis, we collected 9 normal pancreatic tissue samples and 41 pancreatic carcinoma samples and stably transfected the human pancreatic carcinoma cell line Panc-1 with a vector capable of expressing TFPI-2 gene. RT-PCR and Western blot analysis revealed that the expression of TFPI-2 in pancreatic carcinoma samples was markedly lower than that in normal pancreas samples, and there was no TFPI-2 expression in Panc-1 cell. Its expression was related with biological characters of pancreatic carcinoma. The results of Boyden chamber assay and orthotopic pancreatic carcinoma model showed that TFPI-2 could inhibit invasion and metastasis ability of pancreatic carcinoma in vitro and in vivo. Kaplan-Meier survival curve and Cox proportional hazards model assay identified TFPI-2 as an independent prognostic factor for pancreatic carcinoma. Our data suggest that TFPI-2 plays a significant role in the invasion and metastasis of pancreatic carcinoma cell in vitro and in vivo and is determined to be an important prognostic factor for pancreatic carcinoma patients.

Tissue factor pathway inhibitor 2 (TFPI-2), also known as placental protein and matrix-associated serine protease inhibitor, plays an important role in angiogenesis, intravascular fibrinolysis, wound healing, tumor invasion, metastasis by plasmin, and trypsin mediated activation of zymogen matrix metalloproteinases. To detect whether TFPI-2 can be expressed in human pancreatic carcinoma samples and to investigate its role in the growth, invasion, and metastasis of pancreatic carcinoma cell in vitro and in vivo, we collected eight normal pancreatic tissue samples and 50 pancreatic carcinoma samples, and stably transfected the human pancreatic carcinoma cell line Panc-1 with a vector capable of expressing TFPI-2 gene. RT-PCR and Western blot analysis revealed that the levels of TFPI-2 expression were markedly lower in pancreatic carcinoma samples compared with normal pancreas samples. The level of TFPI-2 protein was significantly higher in cells transfected with TFPI-2 gene than that in the untransfected cells. The results of MTT assay showed that TFPI-2 inhibited Panc-1 cells growth in vitro. The invasive capacity of the cells transfected with TFPI-2 gene was also markedly less than that of untransfected cells in vitro as determined by the Matrigel invasion/migration assay. Moreover, TFPI-2 inhibited tumor growth, invasion, and metastasis in vivo in an orthotopic pancreatic carcinoma model. Our findings suggest that TFPI-2 plays a significant role in the growth, invasion, and metastasis of pancreatic carcinoma cell in vitro and in vivo, and has potential in anticancer therapy.