Tumor targeting with a selective gelatinase inhibitor.

Several lines of evidence suggest that tumor growth, angiogenesis, and metastasis are dependent on matrix metalloproteinase (MMP) activity. However, the lack of inhibitors specific for the type IV collagenase/gelatinase family of MMPs has thus far prevented the selective targeting of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) for therapeutic intervention in cancer. Here, we describe the isolation of specific gelatinase inhibitors from phage display peptide libraries. We show that cyclic peptides containing the sequence HWGF are potent and selective inhibitors of MMP-2 and MMP-9 but not of several other MMP family members. Our prototype synthetic peptide, CTTHWGFTLC, inhibits the migration of human endothelial cells and tumor cells. Moreover, it prevents tumor growth and invasion in animal models and improves survival of mice bearing human tumors. Finally, we show that CTTHWGFTLC-displaying phage specifically target angiogenic blood vessels in vivo. Selective gelatinase inhibitors may prove useful in tumor targeting and anticancer therapies.     

Retracted: Resistin effects on pancreatic cancer progression and chemoresistance are mediated through its receptors CAP1 and TLR4

Resistin, secreted by macrophages in tumor microenvironment, has never been investigated in pancreatic cancer models, despite a vibrant tumor microenvironment around pancreatic tumors. We evaluated serum resistin levels in healthy individuals versus pancreatic cancer patients representing different tumor grades. In vitro mechanistic analysis involved MiaPaCa-2 and SW1990 cells. Resistin signaling depends on binding of resistin to its cognitive receptors. Therefore, we silenced adenylyl cyclase-associated protein 1 (CAP1) and toll-like receptor 4 (TLR4), its two known receptors, individually as well as in combination, by short hairpin RNA (shRNA). Effect of resistin on cell proliferation, migration, invasion, cell cycle, and sensitivity to gemcitabine was studied without or with silencing of resistin receptors CAP1 and/or TLR4. The results were also confirmed in vivo in mice xenografted with MiaPaCa-2 cells without or with receptor silencing. We report high resistin levels in pancreatic cancer patients which correlate positively with tumor grades. We observed a marked reduction in the resistin-induced proliferation, migration, invasion, and cell cycle of pancreatic cancer cells MiaPaCa-2 and SW1990 when the receptors were silenced. The results were confirmed in vivo wherein resistin effects were significantly attenuated in MiaPaCa-2 xenografts with silenced receptors. The combined silencing of CAP1 and TLR4 was found to be most effective in vitro and in vivo. We found activation of STAT3 by resistin in vivo and in vitro which was dependent on the presence of CAP1 and TLR4. Further, resistin was found to induce resistance to gemcitabine through its receptors. Our results describe novel functional roles of resistin with implications toward a better understanding of pancreatic tumor microenvironment.     

Hypoxia-reoxygenation increase invasiveness of PANC-1 cells through Rac1/MMP-2

Pancreatic cancer is an aggressive malignancy with proclivity to early metastasis. High expression and activation of the collagenase matrix metalloproteinase-2 (MMP-2) have been found in human pancreatic cancer tissues, being these increased levels of active MMP-2 correlated to tumor invasion and metastasis. Hypoxia and reoxygenation (H-R) are critical pathophysiological conditions during ischemia-reperfusion injury, which has been shown to enhance both invasion and metastasis. In the present study, we investigated the effects of H-R on MMP-2 levels and the invasiveness properties of human pancreatic cancer cells PANC-1. Using specific inhibitors, we found that H-R treatment of these tumor cells induced secretion and activation of MMP-2, which was required for H-R-stimulated basement membrane degradation and cell invasion. Our results also indicate that signaling events involved in H-R-enhanced PANC-1 invasiveness comprehend PI3K-dependent activation of Rac1, which mediated the formation of NADPH-generated reactive oxygen species responsible for MMP-2 secretion and activation.     

Design,synthesis, and biological evaluation of a cephalosporin-monohydroguaiaretic acid prodrug activated by a monoclonal antibody-beta-lactamase conjugate

A novel cephalosporin derivative of monohydroguaiaretic acid (cephem-M(3)N, 7) was synthesized and found to possess anticancer activity against human leukemia (K562), breast carcinoma (MCF7), human lung cancer (A549), human colon cancer (Colo205) and pancreatic cancer cells (Capan2 and MiaPaCa2). A tumor targeting fusion protein (dsFv3-beta-lactamase) was also used in conjunction with cephem-based M(3)N 7 and its potency toward K562, MCF7, A549, Colo205, Capan2, and MiaPaCa2 was found to approach that of the free M(3)N (4). In the presence of dsFv3-beta-lactamase, tumor cells were found to be much more susceptible to conjugate 7 than normal human embryonic lung (HEL) cells and normal fibroblasts (Hef522). These notions provide a new approach to the use of nordihydroguaiaretic acid (NDGA) and its derivatives for antitumor therapy.     

The inhibitory effects of immunosuppressive factors, dexamethasone and interleukin-4, on NF-kappaB-mediated protease production by oral cancer.

Matrix metalloproteinase-9 (MMP-9) produced by tumor cells is known to be implicated in the invasion of squamous cell carcinoma (SCC). In the process of searching for agents to inhibit MMP-9 in cancer, immunosuppressive factors, dexamethasone (DEX) and interleukin-4 (IL-4) were found to inhibit protein production as well as gene expression of MMP-9 in tumor necrosis factor alpha (TNFalpha)-stimulated SCC cells. DEX and IL-4 could also suppress the expression of urokinase type plasminogen activator (uPA) to prevent the conversion from the proenzyme form of MMP-9 to its active form. Regarding their mechanisms to inhibit the expression of MMP-9 and uPA, DEX and IL-4 had no effect on the cell surface levels of TNFalpha receptors, but inhibited the activation of NF-kappaB and NF-kappaB-dependent gene expression. DEX, but not IL-4, could strongly augment the TNFalpha-induced expression of IkappaBalpha in SCC cells. These results suggest that DEX and IL-4 suppress not only immunological reactions, but also tumor invasion by targeting NF-kappaB.     

Haishengsu, a Protein from Shellfish Tegillarca L. granosa, Inhibits the Growth and the Activity of Matrix Metalloproteinases-2 and -9 in Human Lung Carcinoma

Haishengsu (HSS) is a seashell protein extracted from Tegillarca L. granosa, a type of Malaysian shellfish. Previous in vitro studies showed that HSS might possess biological anticancer activity. In this combined in vitro and in vivo study, we investigated the inhibitory effects of HSS on tumor growth, invasion, and metastasis using human lung carcinoma cell lines A549 and NCI-H292, both intensely positive for matrix metalloproteinases-2 (MMP-2) and MMP-9. HSS significantly inhibited the proliferation of A549 and NCI-H292 as estimated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The transwell chamber assay showed that HSS effectively blocked the invasion and migration of the carcinoma cells through the reconstituted extracellular matrix (Matrigel). Gelatin zymography analysis revealed that the secretion and activity of MMP-2 and MMP-9 in the supernatants of the cultured cells A549 and NCI-H292 were decreased after treatment with HSS. The levels of MMP-2 and MMP-9 in these cancer cells were further examined by Western blot assay in which a significant decrease of MMP-2 and MMP-9 was observed in A549 and NCI-H292 cells after 24 h of exposure to HSS. The anticancer activity of HSS was verified in a mouse model in which HSS delayed the growth of A549 xenografts after 3 weeks of oral administration. Inhibition of MMP-2 and MMP-9 expression was also demonstrated in the A549 xenografts as determined by Western blot analysis. These results suggest that HSS is a novel seashell protein that cannot only inhibit tumor growth but also prevent tumor invasion and metastasis through suppressing the activity of MMP-2 and MMP-9.     

SDF-1α upregulation of MMP-2 is mediated by p38 MAPK signaling in pancreatic cancer cell lines

Pancreatic cancer is highly invasive and is currently the fourth leading cause of cancer death worldwide. CXC chemokine receptor-4 (CXCR4) is a G protein-coupled receptor for CXC chemokine ligand 12/stromal cell-derived factor-1α (SDF-1α), a member of a large family of small, structurally related, heparin-binding chemokine proteins. SDF-1α/CXCR4 plays an important role in tumor growth, invasion, metastasis, and angiogenesis. SDF-1α and CXCR4 are upregulated in many tumors, including pancreatic cancer tissues, and preliminary data indicate that the SDF-1/CXCR4 axis plays an important role in tumor invasion. However, their precise role and the mechanism through which they function remain largely unknown. In this study, analysis of SDF-1α, CXCR4 and MMP-2 expression in pancreatic cancer and adjacent tissue samples from ten patients revealed that all three proteins are overexpressed in human pancreatic cancer. SDF-1α induced MMP-2 and MMP-9 upregulation in PANC-1 and SW-1990 cells, which was associated with increased pancreatic cancer cell proliferation and invasion. Furthermore, SDF-1α induced p38 phosphorylation and p38 inhibition reduced both the level of SDF-1α-stimulated MMP-2 expression and PANC-1 cell invasion. Overall, our results demonstrate that SDF-1α/CXCR4 upregulates MMP-2 expression and induces pancreatic cancer cell invasion in PANC-1 and SW-1990 cell lines by activating p38 MAPK.     

Detection of MMP-2 and MMP-9 activity in vivo with a triple-helical peptide optical probe

We report a novel activatable NIR fluorescent probe for in vivo detection of cancer-related matrix metalloproteinase (MMP) activity. The probe is based on a triple-helical peptide substrate (THP) with high specificity for MMP-2 and MMP-9 relative to other members of the MMP family. MMP-2 and MMP-9 (also known as gelatinases) are specifically associated with cancer cell invasion and cancer-related angiogenesis. At the center of each 5 kDa peptide strand is a gelatinase sensitive sequence flanked by 2 Lys residues conjugated with NIR fluorescent dyes. Upon self-assembly of the triple-helical structure, the 3 peptide chains intertwine, bringing the fluorophores into close proximity and reducing fluorescence via quenching. Upon enzymatic cleavage of the triple-helical peptide, 6 labeled peptide chains are released, resulting in an amplified fluorescent signal. The fluorescence yield of the probe increases 3.8-fold upon activation. Kinetic analysis showed a rate of LS276-THP hydrolysis by MMP-2 (k(cat)/K(M) = 30,000 s(-1) M(-1)) similar to that of MMP-2 catalysis of an analogous fluorogenic THP. Administration of LS276-THP to mice bearing a human fibrosarcoma xenografted tumor resulted in a tumor fluorescence signal more than 5-fold greater than that of muscle. This signal enhancement was reduced by treatment with the MMP inhibitor Ilomostat, indicating that the observed tumor fluorescence was indeed enzyme mediated. These results are the first to demonstrate that triple-helical peptides are suitable for highly specific in vivo detection of tumor-related MMP-2 and MMP-9 activity.     

Resveratrol inhibits heregulin-beta1-mediated matrix metalloproteinase-9 expression and cell invasion in human breast cancer cells

The growth factor heregulin-β1 (HRG-β1), which is expressed in breast cancer, activates the HER-2 signaling pathway through induction of heterodimeric complexes of HER-2 with HER-3 or HER-4. It has been shown in many studies that HRG-β1 induces the tumorigenicity and metastasis of breast cancer cells. Matrix metalloproteinase (MMP) 9 is a key enzyme in the degradation of extracellular matrices, and its expression may be dysregulated in breast cancer invasion and metastasis. Resveratrol, a major component in grape, exhibited potential anticarcinogenic activities in both in vitro and in vivo studies. However, the inhibitory effect of resveratrol on HER-2-mediated expression of MMP-9 has not been demonstrated yet.

In the present study, we investigated the anti-invasive mechanism of resveratrol in human breast cancer cells. Human breast cancer MCF-7 cells were exposed to resveratrol (2, 5 and 10 μM). The expression activity of MMP-9 was measured by zymogram analysis. Phosphorylated levels of HER-2 and mitogen-activated protein kinase (MAPK)/ERK were measured by Western blot analysis. Total actin was used as internal control for protein expression. HRG-β1 induced the phosphorylation of HER-2/neu receptor and MMP-9 expression in human breast cancer MCF-7 cells. Resveratrol significantly inhibited HRG-β1-mediated MMP-9 expression in human breast cancer cells. MEK inhibitor induced a marked reduction in MMP-9 expression, and it suggested that ERK1/2 cascade could play an important role in HRG-β1-mediated MMP-9 expression. Furthermore, resveratrol significantly suppressed HRG-β1-mediated phosphorylation of ERK1/2 and invasion of breast cancer cells. However, resveratrol had negligible effects on either HRG-β1-mediated phosphorylation of HER-2 receptor or expression of the tissue inhibitor of MMP, tissue inhibitor metalloproteinase protein 1.

Taken together, our results suggest that resveratrol inhibited MMP-9 expression in human breast cancer cells. The inhibitory effects of resveratrol on MMP-9 expression and invasion of breast cancer cells are, in part, associated with the down-regulation of the MAPK/ERK signaling pathway.     

EGF promotes invasion by PANC-1 cells through Rac1/ROS-dependent secretion and activation of MMP-2

Cancer metastasis involves tumor cells invading the surrounding tissue. Remodeling of tissue barriers depends on the ability of tumor cells to degrade the surrounding collagen matrix and then migrate through the matrix defects. Epidermal growth factor (EGF) has been shown to regulate tumor cell invasion through activation of matrix metalloproteinase-2 (MMP-2) in various tumor cell types. In the present study, we investigated the role of MMP-2 and the signaling pathway involved in EGF-promoted invasion by human pancreatic cancer cells PANC-1. Using specific inhibitors, we found that EGF stimulation of these tumor cells induced secretion and activation of the collagenase MMP-2, which was required for EGF-stimulated basement membrane degradation and cell invasion. Our results also indicate that signaling events downstream of EGF receptor involved PI3K- and Src-dependent activation of Rac1, which mediated the NADPH-generated reactive oxygen species responsible for MMP-2 secretion and activation.     

基质金属蛋白酶2抑制剂的筛选及鉴定

以原核表达的具有明胶水解活性的人基质金属蛋白酶 2的催化区 (MCD)为靶标 ,筛选噬菌体随机环七肽库和十二肽库 .找到 6种与MCD特异结合的小肽 ,将 6种小肽基因分别与GST表达质粒重组 ,进行GST融合表达 ,制备融合蛋白 .采用Glutathione Sepharose 4B亲和层析法纯化融合蛋白 ,通过酶抑制实验、体外侵袭实验检测融合蛋白的活性 .结果表明 ,GST C71能够抑制MCD水解 β酪蛋白的活性 ,并且对人纤维肉瘤细胞HT10 80的体外侵袭有明显的抑制作用     

TIMP-2 fusion protein with human serum albumin potentiates anti-angiogenesis-mediated inhibition of tumor growth by suppressing MMP-2 expression

TIMP-2 protein has been intensively studied as a promising anticancer candidate agent, but the in vivo mechanism underlying its anticancer effect has not been clearly elucidated by previous works. In this study, we investigated the mechanism underlying the anti-tumor effects of a TIMP-2 fusion protein conjugated with human serum albumin (HSA/TIMP-2). Systemic administration of HSA/TIMP-2 effectively inhibited tumor growth at a minimum effective dose of 60 mg/kg. The suppressive effect of HSA/TIMP-2 was accompanied by a marked reduction of in vivo vascularization. The anti-angiogenic activity of HSA/TIMP-2 was directly confirmed by CAM assays. In HSA/TIMP-2-treated tumor tissues, MMP-2 expression was profoundly decreased without a change in MT1-MMP expression of PECAM-1-positive cells. MMP-2 mRNA was also decreased by HSA/TIMP-2 treatment of human umbilical vein endothelial cells. Zymographic analysis showed that HSA/TIMP-2 substantially decreased extracellular pro-MMP-2 activity (94-99% reduction) and moderately decreased active MMP-2 activity (10-24% reduction), suggesting MT1-MMP-independent MMP-2 modulation. Furthermore, HSA/TIMP-2 had no effect on in vitro active MMP-2 activity and in vivo MMP-2 activity. These studies show that HSA/TIMP-2 potentiates anti-angiogenic activity by modulating MMP-2 expression, but not MMP-2 activity, to subsequently suppress tumor growth, suggesting an important role for MMP-2 expression rather than MMP-2 activity in anti-angiogenesis.     

Quiescin sulfhydryl oxidase 1 promotes invasion of pancreatic tumor cells mediated by matrix metalloproteinases

Quiescin sulfhydryl oxidase 1 (QSOX1) oxidizes sulfhydryl groups to form disulfide bonds in proteins. We previously mapped a peptide in plasma from pancreatic ductal adenocarcinoma (PDA) patients back to an overexpressed QSOX1 parent protein. In addition to overexpression in pancreatic cancer cell lines, 29 of 37 patients diagnosed with PDA expressed QSOX1 protein in tumor cells, but QSOX1 was not detected in normal adjacent tissues or in a transformed, but nontumorigenic cell line. To begin to evaluate the advantage QSOX1 might provide to tumors, we suppressed QSOX1 protein expression using short hairpin (sh) RNA in two pancreatic cancer cell lines. Growth, cell cycle, apoptosis, invasion, and matrix metalloproteinase (MMP) activity were evaluated. QSOX1 shRNA suppressed both short and long isoforms of the protein, showing a significant effect on cell growth, cell cycle, and apoptosis. However, QSOX1 shRNA dramatically inhibited the abilities of BxPC-3 and Panc-1 pancreatic tumor cells to invade through Matrigel in a modified Boyden chamber assay. Mechanistically, gelatin zymography indicated that QSOX1 plays an important role in activation of MMP-2 and MMP-9. Taken together, our results suggest that the mechanism of QSOX1-mediated tumor cell invasion is by activation of MMP-2 and MMP-9.     

Aspirin inhibits matrix metalloproteinase-2 activity, increases E-cadherin production, and inhibits in vitro invasion of tumor cells

Aspirin (acetylsalicylic acid) is a widely used anti-inflammatory drug. Recently, aspirin was shown to reduce the risk of development of cancer and mortality from it. Tumor metastasis is the most important cause of cancer death. The aim of the present study was to investigate if aspirin affects the invasion of cancer cells. Matrix metalloproteinases (MMPs) and cell adhesion molecules play important roles in the modulation of tumor invasion. Gelatin-based zymography assay showed that aspirin inhibited MMP-2 activity of SK-Hep-1 cancer cells. Matrigel-based chemoinvasion assay showed that aspirin inhibited in vitro invasion of SK-Hep-1 cancer cells. Aspirin treatment also increased the production of the cell adhesion molecule, E-cadherin, in Hep G2 cancer cells. Aspirin is a cyclooxygenase (COX) inhibitor. Treatment of cells with another COX inhibitor, sulindac, also inhibited MMP-2 activity and increased E-cadherin production of cells. These results indicate that aspirin can modulate both MMP-2 and E-cadherin production and therein may possess antimetastatic effect.     

Retracted: Curcumin derivative L6H4 inhibits proliferation and invasion of gastric cancer cell line BGC-823

Curcumin and its chalcone derivatives have well-known, explicit biological antitumor properties, such as instance antiproliferative and apoptotic effects via multiple molecular targets. In this study, we investigated the anticancer activity of curcumin derivative L6H4 (curcumin L6H4) on gastric cancer cells. Inhibitory effects of curcumin L6H4 on gastric cancer cells (BGC-823) were studied by the diphenyltetrazolium (MTT) assay, and cell apoptosis was detected by Annexin-V/propidium iodide (PI) staining and then analyzed by flow cytometry. A mouse xenotransplant gastric tumor model was established to detect the role of curcumin L6H4 in vivo. The apoptosis-related proteins p53, p21, Bax, and Bcl-2 in BGC-823 cells and mouse xenotransplant models treated with curcumin L6H4 were determined by Western blot analysis. Curcumin L6H4 can significantly inhibit the proliferation and induce the apoptosis of BGC-823 cells, thus enhancing the expression levels of p53, p21, Bax, and Bcl-2 noticeably in vivo and in vitro. Meanwhile, curcumin L6H4 can remarkably suppress the growth of tumor cells in animal models. These results suggest that curcumin derivative L6H4 has potent of antitumor properties in vitro or in vivo.     

The membrane-anchored MMP inhibitor RECK is a key regulator of extracellular matrix integrity and angiogenesis.

Matrix metalloproteinases (MMPs) are essential for proper extracellular matrix remodeling. We previously found that a membrane-anchored glycoprotein, RECK, negatively regulates MMP-9 and inhibits tumor invasion and metastasis. Here we show that RECK regulates two other MMPs, MMP-2 and MT1-MMP, known to be involved in cancer progression, that mice lacking a functional RECK gene die around E10.5 with defects in collagen fibrils, the basal lamina, and vascular development, and that this phenotype is partially suppressed by MMP-2 null mutation. Also, vascular sprouting is dramatically suppressed in tumors derived from RECK-expressing fibrosarcoma cells grown in nude mice. These results support a role for RECK in the regulation of MMP-2 in vivo and implicate RECK downregulation in tumor angiogenesis.