Establishment of Structure-Function Relationship of Tissue Inhibitor of Metalloproteinase-1 for Its Interaction with CD63: Implication for Cancer Therapy.

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a pleiotropic protein, promoting both tumor-suppressive and tumor-promoting activities. While TIMP-1 is primarily known as an endogenous inhibitor of matrix metalloproteinases (MMPs) and thus associated with tumor cell invasion, clinical studies demonstrated increased expression of TIMP-1 and its association with poor prognosis in cancer. Non-MMP-inhibitory and oncogenic functions of TIMP-1 are mediated by induction of intracellular signaling via its cell surface receptor CD63, a tetraspanin.

An oncogenic activity of PDGF-C and its splice variant in human breast cancer.

Despite strong evidence for the involvement of PDGF signaling in breast cancer, little is known about the PDGF ligand responsible for PDGFR activation during breast cancer progression. Here, we found PDGF-C to be highly expressed in breast carcinoma cell lines. Immunohistochemical analysis of invasive breast cancer revealed an association between increased PDGF-C expression and lymph node metastases, Ki-67 proliferation index, and poor disease-free survival.

HPV-associated differential regulation of tumor metabolism in oropharyngeal head and neck cancer.

HPV-positive oropharyngeal cancer patients experience significantly lower locoregional recurrence and higher overall survival in comparison with HPV-negative patients, especially among those who received radiation therapy. The goal of the present study is to investigate the molecular mechanisms underlying the differential radiation sensitivity between HPV-negative and HPV-positive head and neck squamous cell carcinoma (HNSCC). Here, we show that HPV-negative HNSCC cells exhibit increased glucose metabolism as evidenced by increased production of lactate, while HPV-positive HNSCC cells effectively utilize mitochondrial respiration as evidenced by increased oxygen consumption.

A novel role for flotillin-1 in H-Ras-regulated breast cancer aggressiveness.

Elevated expression and aberrant activation of Ras have been implicated in breast cancer aggressiveness. H-Ras, but not N-Ras, induces breast cell invasion. A crucial link between lipid rafts and H-Ras function has been suggested.

Dynamic regulation of platelet-derived growth factor D (PDGF-D) activity and extracellular spatial distribution by matriptase-mediated proteolysis.

The oncogenic roles of PDGF-D and its proteolytic activator, matriptase, have been strongly implicated in human prostate cancer. Latent full-length PDGF-D (FL-D) consists of a CUB domain, a growth factor domain (GFD), and the hinge region in between. Matriptase processes the FL-D dimer into a GFD dimer (GFD-D) in a stepwise manner, involving generation of a hemidimer (HD), an intermediate product containing one FL-D subunit and one GFD subunit.

Discoidin domain receptor 1 is a novel transcriptional target of ZEB1 in breast epithelial cells undergoing H-Ras-induced epithelial to mesenchymal transition.

The epithelial-to-mesenchymal transition (EMT) process allows carcinoma cells to dissociate from the primary tumor thereby facilitating tumor cell invasion and metastasis. Ras-dependent hyperactive signaling is commonly associated with tumorigenesis, invasion, EMT, and metastasis. However, the downstream effectors by which Ras regulates EMT remain ill defined.

TIMP-1 via TWIST1 induces EMT phenotypes in human breast epithelial cells.

Unlabelled: Tissue inhibitor of metalloproteinase-1 (TIMP-1) regulates intracellular signaling networks for inhibition of apoptosis. Tetraspanin (CD63), a cell surface binding partner for TIMP-1, was previously shown to regulate integrin-mediated survival pathways in the human breast epithelial cell line MCF10A. In the current study, we show that TIMP-1 expression induces phenotypic changes in cell morphology, cell adhesion, cytoskeletal remodeling, and motility, indicative of an epithelial-mesenchymal transition (EMT).

Bone-induced c-kit expression in prostate cancer: a driver of intraosseous tumor growth.

Loss of BRCA2 function stimulates prostate cancer (PCa) cell invasion and is associated with more aggressive and metastatic tumors in PCa patients. Concurrently, the receptor tyrosine kinase c-kit is highly expressed in skeletal metastases of PCa patients and induced in PCa cells placed into the bone microenvironment in experimental models. However, the precise requirement of c-kit for intraosseous growth of PCa and its relation to BRCA2 expression remain unexplored.

A critical role of the PTEN/PDGF signaling network for the regulation of radiosensitivity in adenocarcinoma of the prostate.

Purpose: Loss or mutation of the phosphate and tensin homologue (PTEN) is a common genetic abnormality in prostate cancer (PCa) and induces platelet-derived growth factor D (PDGF D) signaling. We examined the role of the PTEN/PDGF axis on radioresponse using a murine PTEN null prostate epithelial cell model.

Methods And Materials: PTEN wild-type (PTEN+/+) and PTEN knockout (PTEN-/-) murine prostate epithelial cell lines were used to examine the relationship between the PTEN status and radiosensitivity and also to modulate the PDGF D expression levels.

A novel function of HPV16-E6/E7 in epithelial-mesenchymal transition.

Human papillomavirus (HPV) 16 is among the most important etiological factors in many human cancers, including head and neck squamous cell carcinomas (HNSCCs) not associated with alcohol or tobacco use. HPV16-E6 and E7 oncoproteins target intracellular signaling networks, altering key molecular and cellular events during tumor progression. The present study investigates the role of HPV16-E6 and E7 oncogenes on the epithelial-mesenchymal transition (EMT), a cellular process thought to be critical for tumor cell invasion and metastasis.

TIMP-1 induces an EMT-like phenotypic conversion in MDCK cells independent of its MMP-inhibitory domain.

Matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) regulate epithelial-mesenchymal transition (EMT) critical for the development of epithelial organs as well as cancer cell invasion. TIMP-1 is frequently overexpressed in several types of human cancers and serves as a prognostic marker. The present study investigates the roles of TIMP-1 on the EMT process and formation of the lumen-like structure in a 3D Matrigel culture of MDCK cells.

PDGF upregulates Mcl-1 through activation of β-catenin and HIF-1α-dependent signaling in human prostate cancer cells.

Background: Aberrant platelet derived growth factor (PDGF) signaling has been associated with prostate cancer (PCa) progression. However, its role in the regulation of PCa cell growth and survival has not been well characterized.

Methodology/principal Findings: Using experimental models that closely mimic clinical pathophysiology of PCa progression, we demonstrated that PDGF is a survival factor in PCa cells through upregulation of myeloid cell leukemia-1 (Mcl-1).

Cediranib inhibits both the intraosseous growth of PDGF D-positive prostate cancer cells and the associated bone reaction.

Background: The major cause of death in prostate cancer (PCa) cases is due to distant metastatic lesions, with the bone being the most prevalent site for secondary colonization. Utilization of small molecule inhibitors to treat bone metastatic PCa have had limited success either as monotherapies or in combination with other chemotherapeutics due to intolerable toxicities. In the current study, we developed a clinically relevant in vivo intraosseous tumor model overexpressing the platelet-derived growth factor D (PDGF D) to test the efficacy of a newly characterized vascular endothelial growth factor receptor (VEGFR)/PDGFR inhibitor, cediranib (also called AZD2171).

PTEN regulates PDGF ligand switch for β-PDGFR signaling in prostate cancer.

Platelet-derived growth factor (PDGF) family members are potent growth factors that regulate cell proliferation, migration, and transformation. Clinical studies have shown that both PDGF receptor β (β-PDGFR) and its ligand PDGF D are up-regulated in primary prostate cancers and bone metastases, whereas PDGF B, a classic ligand for β-PDGFR, is not frequently detected in clinical samples. In this study, we examined the role of the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in the regulation of PDGF expression levels using both a prostate-specific, conditional PTEN-knockout mouse model and mouse prostate epithelial cell lines established from these mice.

Platelet-derived growth factor-C (PDGF-C) activation by serine proteases: implications for breast cancer progression.

The PDGF (platelet-derived growth factor) family members are potent mitogens for cells of mesenchymal origin and serve as important regulators of cell migration, survival, apoptosis and transformation. Tumour-derived PDGF ligands are thought to function in both autocrine and paracrine manners, activating receptors on tumour and surrounding stromal cells. PDGF-C and -D are secreted as latent dimers, unlike PDGF-A and -B.

Identification of H-Ras-specific motif for the activation of invasive signaling program in human breast epithelial cells.

Increased expression and/or activation of H-Ras are often associated with tumor aggressiveness in breast cancer. Previously, we showed that H-Ras, but not N-Ras, induces MCF10A human breast epithelial cell invasion and migration, whereas both H-Ras and N-Ras induce cell proliferation and phenotypic transformation. In an attempt to determine the sequence requirement directing the divergent phenotype induced by H-Ras and N-Ras with a focus on the induction of human breast cell invasion, we investigated the structural and functional relationships between H-Ras and N-Ras using domain-swap and site-directed mutagenesis approaches.

A novel signaling axis of matriptase/PDGF-D/ß-PDGFR in human prostate cancer.

Increasing evidence indicates the significance of platelet-derived growth factor receptor-β (β-PDGFR) signaling in prostate cancer (PCa). Accordingly, preclinical studies suggest the potential of β-PDGFR as a therapeutic target in metastatic PCa. However, a ligand responsible for β-PDGFR activation in PCa was unknown, and recent clinical trials with imatinib mesylate showed limited success due to normal tissue toxicity.

Posttranslational regulation of membrane type 1-matrix metalloproteinase (MT1-MMP) in mouse PTEN null prostate cancer cells: Enhanced surface expression and differential O-glycosylation of MT1-MMP.

Membrane type 1 (MT1)-matrix metalloproteinase (MT1-MMP) is a membrane-tethered MMP that has been shown to play a key role in promoting cancer cell invasion. MT1-MMP is highly expressed in bone metastasis of prostate cancer (PC) patients and promotes intraosseous tumor growth of PC cells in mice. The majority of metastatic prostate cancers harbor loss-of-function mutations or deletions of the tumor suppressor PTEN (phosphatase and tensin homologue deleted on chromosome ten).

Shedding of RANKL by tumor-associated MT1-MMP activates Src-dependent prostate cancer cell migration.

Membrane type 1 matrix metalloproteinase (MT1-MMP) plays an essential role in protease-mediated extracellular matrix (ECM) degradation, but it also functions as a sheddase releasing non-ECM substrates such as receptor activator of NF-kappaB ligand (RANKL), an osteoclastogenic factor typically confined to the surface of osteoblasts. We previously found high expression of MT1-MMP in skeletal metastasis of prostate cancer patients, in a pattern similar to RANKL expression. We also showed that overexpression of MT1-MMP in prostate cancer cells increases tumor growth and osteolysis in an intratibial mouse model of bone metastasis, and that soluble factor(s) shed by tumor-derived MT1-MMP enhance osteoclast differentiation in a RANKL-dependent manner.

miR-200 regulates PDGF-D-mediated epithelial-mesenchymal transition, adhesion, and invasion of prostate cancer cells.

MicroRNAs have been implicated in tumor progression. Recent studies have shown that the miR-200 family regulates epithelial-mesenchymal transition (EMT) by targeting zinc-finger E-box binding homeobox 1 (ZEB1) and ZEB2. Emerging evidence from our laboratory and others suggests that the processes of EMT can be triggered by various growth factors, such as transforming growth factor beta and platelet-derived growth factor-D (PDGF-D).

Global gene expression profiling unveils S100A8/A9 as candidate markers in H-ras-mediated human breast epithelial cell invasion.

The goal of the present study is to unveil the gene expression profile specific to the biological processes of human breast epithelial cell invasion and migration using an MCF10A model genetically engineered to constitutively activate the H-ras or N-ras signaling pathway. We previously showed that H-Ras, but not N-Ras, induces MCF10A cell invasion/migration, whereas both H-Ras and N-Ras induce cell proliferation and phenotypic transformation. Thus, these cell lines provide an experimental system to separate the gene expression profile associated with cell invasion apart from cell proliferation/transformation.

Platelet-derived growth factor-D overexpression contributes to epithelial-mesenchymal transition of PC3 prostate cancer cells.

The majority of human malignancies are believed to have epithelial origin, and the progression of cancer is often associated with a transient process named epithelial-mesenchymal transition (EMT). EMT is characterized by the loss of epithelial markers and the gain of mesenchymal markers that are typical of "cancer stem-like cells," which results in increased cell invasion and metastasis in vivo. Therefore, it is important to uncover the mechanistic role of factors that may induce EMT in cancer progression.

Mammalian target of rapamycin repression by 3,3'-diindolylmethane inhibits invasion and angiogenesis in platelet-derived growth factor-D-overexpressing PC3 cells.

Platelet-derived growth factor-D (PDGF-D) is a newly recognized growth factor known to regulate many cellular processes, including cell proliferation, transformation, invasion, and angiogenesis. Recent studies have shown that PDGF-D and its cognate receptor PDGFR-beta are expressed in prostate tumor tissues, suggesting that PDGF-D might play an important role in the development and progression of prostate cancer. However, the biological role of PDGF-D in tumorigenesis remains elusive.

Hyperthermia enhances tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human cancer cells.

Purpose: This study investigated whether hyperthermia can enhance TRAIL-induced apoptotic death.

Methods: Human prostate adenocarcinoma DU-145, human pancreatic carcinoma MIA PaCa-2 and BxPC-3, human colon fibroblast CCD-33Co and rat prostate endothelial YPEN-1 cells were treated with various concentrations of TRAIL (0-200 ngml(-1)) with hyperthermia (40-42 degrees C).

Results: It was observed in human cancer cells, but not in normal cells, that TRAIL induced apoptotic death and also that hyperthermia (40-42 degrees C) promoted TRAIL-induced apoptotic death.

Identification of CD63 as a tissue inhibitor of metalloproteinase-1 interacting cell surface protein.

This study identified CD63, a member of the tetraspanin family, as a TIMP-1 interacting protein by yeast two-hybrid screening. Immunoprecipitation and confocal microscopic analysis confirmed CD63 interactions with TIMP-1, integrin beta1, and their co-localizations on the cell surface of human breast epithelial MCF10A cells. TIMP-1 expression correlated with the level of active integrin beta1 on the cell surface independent of cell adhesion.