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Veli-Matti Kähäri

Publications and source records attributed to Veli-Matti Kähäri.

At least 19 recordsLinked to original sources
PubMed2006

Collagenase-3 (MMP-13) enhances remodeling of three-dimensional collagen and promotes survival of human skin fibroblasts.

Collagenase-3 (MMP-13) is a matrix metalloproteinase capable of cleaving a multitude of extracellular matrix proteins in addition to fibrillar collagens. Human MMP-13 is expressed by fibroblasts in chronic cutaneous ulcers, but not in normally healing adult skin wounds. However, MMP-13 is produced by fibroblasts in adult gingival and in fetal skin wounds characterized by rapid collagen remodeling and scarless healing. Here, we have examined the role of human MMP-13 in remodeling of three-dimensional (3D) collagenous matrix by primary adult human skin fibroblasts. The high level of human MMP-13 expression by fibroblasts achieved by adenoviral gene delivery resulted in potent enhancement of remodeling and contraction of 3D collagen. Fibroblasts expressing MMP-13 in 3D collagen possessed altered filamentous actin morphology with patch-like actin distribution in cell extensions. The expression of MMP-13 promotes survival and proliferation of fibroblasts in floating collagen gel, and results in activation of Akt and extracellular signal-regulated kinase-1/2 by these cells. The results provide evidence for a novel role for human MMP-13 in regulating dermal fibroblast survival, proliferation, and interaction in 3D collagen, which may be an important survival mechanism for fibroblasts in chronic skin ulcers and contribute to scarless healing of adult gingival and fetal skin wounds.

Actins↗
PubMed2006

Oncolytic capacity of attenuated replicative semliki forest virus in human melanoma xenografts in severe combined immunodeficient mice.

Oncolytic viruses have gained attention as a novel form of cancer treatment. Many viral vectors in use today have been rendered safe by deletion of genes encoding viral structural proteins, thus making them unable to spread beyond the first infected cells. Hence, such replication-deficient constructs may lack efficacy. Here, we analyzed the oncolytic potential of the replication-competent vector VA7-EGFP, based on the avirulent Semliki Forest virus (SFV) strain A7(74), to kill cancer cells in culture as well as to target s.c. human melanoma xenografts in severe combined immunodeficient (SCID) mice. VA7-EGFP was able to infect most cancer cell lines studied, leading to complete lysis of the cells within 72 hours after infection. In SCID mice grafted with A2058 human melanoma, marked regression of the xenografts was observed following a single injection of 10(6) plaque-forming units of virus given either i.p., i.v., or intratumorally. Histologic analysis revealed the presence of virus not only in all treated tumors but also in the brains of the treated mice, causing progressing neuropathology beginning at day 16 after infection. Following initial oncolysis, clusters of viable tumor cells were observed embedded in connective tissue, and at later stages, encapsulated tumor nodules had formed. Infection of melanoma cells from explant cultures of these nodules revealed that a portion of the cells were resistant to virus. To be eligible for use in virotherapy, the ability of avirulent SFV to spread within tumor tissue may have to be improved and the biological safety of the virus may have to be addressed thoroughly in higher animals.

Animals↗
PubMed2006

Isoform-specific regulation of the actin-organizing protein palladin during TGF-beta1-induced myofibroblast differentiation.

Contractile myofibroblasts are responsible for remodeling of extracellular matrix during wound healing; however, their continued activity results in various fibrocontractive diseases. Conversion of fibroblasts into myofibroblasts is induced by transforming growth factor-beta1 (TGF-beta1) and is hallmarked by the neo-expression of alpha-smooth muscle actin (alpha-SMA), a commonly used myofibroblast marker. Moreover, myofibroblast differentiation and acquisition of the contractile phenotype involves functionally important alterations in the expression of actin-organizing proteins. We investigated whether myofibroblast differentiation is accompanied by changes in the expression of palladin, a cytoskeletal protein that controls stress fiber integrity. Palladin is expressed as several isoforms, including major 3Ig (90 kDa) and 4Ig (140 kDa) forms that differ in their N-terminal sequence. Expression of the 4Ig isoform is strongly induced in fibroblast stress fibers upon TGF-beta1 treatment preceding alpha-SMA upregulation. TGF-beta1 induced upregulation of palladin is mediated both by Smad and mitogen-activated protein kinase pathways. Furthermore, palladin 4Ig-isoform is co-expressed with alpha-SMA in vivo in experimental rat wounds and in human myofibroblast-containing lesions. Taken together these results identify palladin 4Ig as a novel marker of myofibroblast conversion in vitro and in vivo. They also provide for the first time information about the signaling cascades involved in the regulation of palladin expression.

Actins↗
PubMed2006

Association between high collagenase-3 expression levels and poor prognosis in patients with head and neck cancer.

BACKGROUND: Squamous cell carcinoma of the head and neck (HNSCC) is a common cancer type. The ability for curative treatment with surgery and radiotherapy (RT) is usually highly dependent on tumor stage at the time of diagnosis. METHODS: The purpose of this study was to determine whether the expression of a cancer-specific proteinase, collagenase-3 (matrix metalloproteinase-13 [MMP-13]), is associated with survival parameters in patients with HNSCC. We studied MMP-13 expression in tumors of 81 patients with stage I-IV HNSCC treated with surgery alone or in combination with radiotherapy. RESULTS: We found a subgroup of patients with high MMP-13 expression level in their tumors (>/=90% MMP-13-positive tumor cells) associated with unfavorable prognosis (median overall survival [OS], 11.8 vs 19.6 months, p = .032). In addition, the median disease-specific survival (DSS) time was markedly reduced in this subgroup (13.8 months vs 40.7 months, p = .062). When the subgroup of patients treated with a curative intent was studied, the same association was found in OS (13.8 vs 24.6 months, p = .023) and DSS (p = .004). In addition, there was a trend for association between >/=90% MMP-13 positivity and a recurrent tumor (p = .078) in curatively treated patients. CONCLUSIONS: The short survival time associated with high MMP-13 expression levels could not be predicted by tumor size or local lymph node invasion. These results show that a high MMP-13 expression level is associated with aggressiveness of HNSCC and may have prognostic value in patient evaluation.

Aged↗
PubMed2005

Temporospatial expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in mouse antigen-induced arthritis.

Several lines of evidence speak for an important role of matrix metalloproteinases (MMPs) in the development of progressive joint destruction. To better understand the role of MMPs and their tissue inhibitors (TIMPs) in this process, we have used the antigen-induced arthritis model to study the temporospatial expression of several MMPs and TIMPs during the progression of arthritis. Arthritis was induced by a single intra-articular injection of methylated bovine serum albumin (mBSA) into one or both knee joints of adult mice previously immunised against mBSA. Samples were collected at 3, 7, 21 and 42 days after induction of arthritis for histology and RNA extraction, and analysed by Northern hybridisation, histochemistry and immunohistochemistry for production of several MMPs and TIMPs -1, -2 and -3. A systematic analysis of MMP and TIMP mRNA levels in mouse knee joints demonstrated a general upregulation of both MMPs and TIMPs during progression of arthritis. Upregulation of MMP-9, -13 and -14 coincided with the advancement of cartilage degeneration, but the expression patterns of MMP-9 and -13 also followed the course of synovial inflammation. TIMPs were steadily upregulated throughout the examination period. Immunohistochemical localisation of MMPs and TIMPs suggested the synovium to be the major source of MMP and TIMP production in arthritis, although articular cartilage chondrocytes also showed an increased production of both MMPs and TIMPs.

Animals↗
PubMed2005

High serum levels of matrix metalloproteinase-9 and matrix metalloproteinase-1 are associated with rapid progression in patients with metastatic melanoma.

PURPOSE: Matrix metalloproteinases (MMP) are proteolytic enzymes that play an important role in various aspects of cancer progression. In the present work, we have studied the prognostic significance of serum levels of gelatinase B (MMP-9), collagenase-1 (MMP-1), and collagenase-3 (MMP-13) in patients with advanced melanoma. EXPERIMENTAL DESIGN: Total pretreatment serum levels of MMP-9 in 71 patients and MMP-1 and MMP-13 in 48 patients were determined by an assay system based on ELISA. Total MMP levels were also assessed in eight healthy controls. The active and latent forms of MMPs were defined by using Western blot analysis and gelatin zymography. RESULTS: Patients with high serum levels of MMP-9 (> or = 376.6 ng/mL; n = 19) had significantly poorer overall survival (OS) than patients with lower serum MMP-9 levels (n = 52; median OS, 29.1 versus 45.2 months; P = 0.033). High MMP-9 levels were also associated with visceral or bone metastasis (P = 0.027), elevated serum alkaline phosphatase level (P = 0.0009), and presence of liver metastases (P = 0.032). Serum levels of MMP-1 and MMP-13 did not correlate with OS. MMP-1 and MMP-9 were found mainly in latent forms in serum, whereas the majority of MMP-13 in serum was active (48 kDa) form. MMP-13 was found more often in active form in patients (mean, 99% of the total MMP-13 level) than in controls (mean, 84% of the total MMP-13 level; P < 0.0001). After initiating the therapy, patients with elevated levels of MMP-1 (> or = 29.8 ng/mL, n = 10) progressed more rapidly than patients with lower levels (median, 1.9 versus 3.5 months; P = 0.023). Serum levels of MMP-9 and MMP-13 did not correlate with the time to progression (TTP). In multivariate analysis with age and gender, MMP-9 or MMP-1 turned out to be independent prognostic factors for OS [P = 0.039; hazard ratio (HR), 1.8; 95% confidence interval (95% CI), 1.03-3.3] or TTP (P = 0.023; HR, 2.7; 95% CI, 1.15-6.4), respectively. CONCLUSIONS: Our findings provide evidence that MMP-1, MMP-9, and MMP-13 play important roles at different phases of metastatic melanoma spread and that serum MMP-9, in particular, could have clinical value in identifying patients at high risk for melanoma progression.

Adult↗
PubMed2005

Smad3 and extracellular signal-regulated kinase 1/2 coordinately mediate transforming growth factor-beta-induced expression of connective tissue growth factor in human fibroblasts.

Connective tissue growth factor (CTGF) is secreted by fibroblasts stimulated with transforming growth factor-beta (TGF-beta). CTGF is a potent enhancer of fibroblast proliferation, chemotaxis, and extracellular matrix deposition, and it is thought to mediate some of the fibrogenic effects of TGF-beta. Here, we have elucidated signaling pathways involved in regulating the TGF-beta-induced production of CTGF in primary fibroblasts. TGF-beta induced the expression of CTGF messenger RNA and protein in human gingival fibroblasts after 2 h of treatment. Adenoviral overexpression of Smad3 enhanced the TGF-beta-elicited expression of CTGF, whereas Smad7 and dominant-negative Smad3 suppressed the effects of TGF-beta on CTGF and Cyr61 expression. Pre-treatment of cells with PD98059, an inhibitor for extracellular signal-regulated kinase (ERK)1/2-activator mitogen-activated protein kinase (MAPK)/ERK kinase (MEK)1, potently inhibited the TGF-beta-induced expression of CTGF. Furthermore, co-expression of Smad3 with constitutively active MEK1 resulted in potent induction of CTGF production without exogenous TGF-beta stimulation. Together, these results demonstrate that Smad3 and ERK1/2 coordinately mediate TGF-beta-induced release of CTGF by fibroblasts. It is conceivable that the crosstalk between Smad3 and ERK1/2 signaling cascades plays an important role in regulating CTGF expression, e.g., in wound repair and tissue fibrosis and could be exploited in therapeutic targeting of fibrotic conditions.

Cells, Cultured↗
PubMed2005

Matrix metalloproteinases as therapeutic targets in cancer.

Degradation of extracellular matrix is crucial for malignant tumor growth, invasion, metastasis and angiogenesis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent neutral endopeptidases collectively capable of degrading essentially all matrix components. Elevated levels of distinct MMPs can be detected in tumor tissue or serum of patients with advanced cancer, and their role as prognostic indicators in cancer has been widely examined. In addition, therapeutic intervention in tumor growth and invasion based on inhibition of MMP activity is under intensive investigation and several MMP inhibitors (MMPIs) are in clinical cancer trials. Even though results of the first clinical trials in advanced cancer have been mostly disappointing, there are also positive results. Recent observations show, that certain MMPs limit tumor growth. Therefore, identification of proper MMPs for therapeutic intervention with array-based molecular classifications of tumors and targeting these with more specific MMPIs in combination with conventional chemotherapy is expected to provide a feasible approach for cancer therapy. MMPIs represent a totally different therapeutic modality from proven anti-cancer drugs and thus traditional approaches to evaluate drug efficiency cannot be used without modification. In this review, we discuss the current view on the feasibility of MMPs as targets for therapeutic intervention in cancer.

Animals↗
PubMed2004

alphaV integrin promotes in vitro and in vivo survival of cells in metastatic melanoma.

The expression of integrin alphaV subunit on 4 melanoma-derived cell lines (A2058, SK-mel-5, WM-115 and WM-266-4) was analyzed. WM-115 cells, which originate from a primary tumor, were negative, whereas all 3 metastasis-derived lines had high levels of alphaV. To study alphaV integrins in the survival of melanoma cells, we developed a novel strategy that is exempt from extracellular inhibitors of ligand binding, which can activate integrin signaling and have integrin-independent effects on apoptosis. A recombinant adenovirus was used to transfer cDNA coding for a single-chain intracellular anti-alphaV integrin antibody into the melanoma cells. Anti-alphaV integrin adenovirus effectively inhibited the cell surface expression of alphaV integrins. In cell culture experiments, the depletion of alphaV integrins detached cells from extracellular matrix and induced apoptosis. Moreover, it prevented WM-266-4 cells from forming tumors in severe combined immunodeficiency mice but it could not prevent the growth of tumors that were formed by alphaV-negative WM-115 cells. Our results indicate that in primary melanomas there are cells that survive without alphaV integrins, whereas during the progression of disease cells can develop a dependency on these receptors. Furthermore, the data oppose the possibility that in melanoma cells apoptosis could occur due to direct activation of caspases by ligand-free alphaV integrins on the cell surface.

Adenoviridae↗
PubMed2004

Targeted inhibition of human collagenase-3 (MMP-13) expression inhibits squamous cell carcinoma growth in vivo.

Squamous cell carcinomas (SCCs) of the head and neck are characterized by a high tendency for local invasion and metastasis to lymph nodes. Collagenase-3 (MMP-13) is specifically expressed by tumor cells in SCCs of the head and neck and its expression correlates with their invasion capacity. To specifically examine the role of MMP-13 in the growth and invasion of SCC, we constructed a hammerhead ribozyme targeted against human MMP-13 mRNA. The anti-MMP-13 ribozyme effectively cleaved MMP-13 transcripts in vitro. Adenoviral delivery of the anti-MMP-13 ribozyme to cutaneous metastatic SCC cells in culture resulted in potent and specific inhibition of the production of proMMP-13 and markedly suppressed invasion of SCC cells through Matrigel. In addition, adenoviral delivery of anti-MMP-13 ribozyme promoted apoptosis in SCC cells within 72 h. Intratumoral injection of anti-MMP-13 ribozyme coding adenovirus into human SCC xenografts established in SCID mice potently suppressed tumor growth, inhibited MMP-13 expression and gelatinolytic activity and reduced the number of proliferating cells within the tumors. These results provide evidence for an important role for MMP-13 in SCC growth and invasion and identify MMP-13 as a promising target for ribozyme-based therapy of SCC in vivo.

Adenoviridae↗
PubMed2003

p38 Mitogen-activated protein kinase pathway suppresses cell survival by inducing dephosphorylation of mitogen-activated protein/extracellular signal-regulated kinase kinase1,2.

Raf/mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK)1,2/extracellular signal-regulated kinase1,2 and MKK3,6/p38 mitogen-activated protein kinase pathways play an important role in cellular survival and apoptosis. The results of this study identify novel mechanisms to explain the opposing effects of these pathways in the regulation of apoptosis induction. Our results show that activation of p38 by adenoviral expression of MKK3b or arsenite treatment was followed by rapid dephosphorylation of MEK1,2 and subsequent apoptosis in human skin fibroblasts. Inhibition of p38 activity by SB203580 and adenoviral expression of dominant-negative forms of p38 potently inhibited MEK1,2 dephosphorylation and apoptosis. Strikingly, p38-mediated dephosphorylation of MEK1,2, was not detected in a series of transformed human cell lines. Taken together, we provide evidence for mechanisms unidentified previously that negatively regulates survival signaling during apoptosis induction. In addition, we show that in all transformed cell lines we have studied thus far, the function of this pathway is impaired.

Apoptosis↗
PubMed2003

Tissue inhibitor of metalloproteinases-3 induces apoptosis in melanoma cells by stabilization of death receptors.

Tissue inhibitors of metalloproteinases (TIMPs) are important regulators of matrix metalloproteinase (MMP) and adamalysin (ADAM) activity. We have previously shown that adenovirally expressed tissue inhibitor of metalloproteinases-3 (TIMP-3) induces apoptosis in melanoma cells and inhibits growth of human melanoma xenografts. Here, we have studied the role of death receptors in apoptosis of melanoma cells induced by TIMP-3. Our results show, that the exposure of three metastatic melanoma cell lines (A2058, SK-Mel-5, and WM-266-4) to recombinant TIMP-3, N-terminal MMP inhibitory domain of TIMP-3, as well as to adenovirally expressed TIMP-3 results in stabilization of tumor necrosis factor receptor-1 (TNF-RI), FAS, and TNF-related apoptosis inducing ligand receptor-1 (TRAIL-RI) on melanoma cell surface and sensitizes these cells to apoptosis induced by TNF-alpha, anti-Fas-antibody and TRAIL. Stabilization of death receptors by TIMP-3 results in activation of caspase-8 and caspase-3, and subsequent apoptosis is blocked by specific caspase-8 inhibitor (Z-IETD-FMK) and by pan-caspase inhibitor (Z-DEVD-FMK). Adenovirus-mediated expression of TIMP-3 in human melanoma xenografts in vivo resulted in increased immunostaining for TNF-RI, FAS, and cleaved caspase-3, and in apoptosis of melanoma cells. Taken together, these results show that TIMP-3 promotes apoptosis in melanoma cells through stabilization of three distinct death receptors and activation of their apoptotic signaling cascade through caspase-8.

Animals↗
PubMed2003

Matrix metalloproteinase-19 is expressed by proliferating epithelium but disappears with neoplastic dedifferentiation.

MMP-19 (also designated RASI) is a recently discovered member of a large family of zinc-dependent proteolytic enzymes, most of which have been implicated in cancer growth and metastasis. It differs from the others by its chromosomal location and structure and is expressed by endothelial and vascular smooth muscle cells in vivo. Our aim was to study the putative role of MMP-19 in skin cancer. We also examined its regulation in keratinocyte cultures using quantitative TaqMan RT-PCR. Our results show that MMP-19 can also be detected in stimulated keratinocytes by Northern and Western analyses. In wounds, it was found in keratinocytes outside the migrating area, while in BCC and SCC, it was present in the hyperproliferative (p63-positive), E-cadherin-negative epidermis at the tumor surface but downregulated in invasive cancer islands. Expression was also evident in endothelial cells of neoangiogenic regions and in occasional stromal fibroblasts. Of the 12 tested cytokines/growth factors, only TNF-alpha and PMA were able to stimulate the expression of MMP-19 mRNA in primary keratinocytes. No MMP-19 mRNA was detected by Northern analysis in cultured HaCaT or A5 cells or in an SCC cell line established from head-and-neck cancer. Our data suggest that, unlike most MMPs, MMP-19 expression in the epidermis is downregulated during transformation and histologic dedifferentiation.

Blotting, Northern↗
PubMed2003

Endothelial cell-matrix interactions.

Dynamic interactions between endothelial cells and components of their surrounding extracellular matrix are necessary for the invasion, migration, and survival of endothelial cells during angiogenesis. These interactions are mediated by matrix receptors that initiate intracellular signaling cascades in response to binding to specific extracellular matrix molecules. The interactions between endothelial cells and their environment are also modulated by enzymes that degrade different matrix components and thus enable endothelial invasion. Recent reports on gene targeting in mice have confirmed the role of two classes of matrix receptors, integrins and cell surface heparan sulfate proteoglycans, and a group of matrix degrading proteolytic enzymes, matrix metalloproteinases, in angiogenesis. The significance of endothelial cell-matrix interactions is further supported by several ongoing clinical trials that analyze the effects of drugs blocking this interaction on angiogenesis-dependent growth of human tumors.

Animals↗
PubMed2003

Matrix metalloproteinase-19 expression in dermal wounds and by fibroblasts in culture.

Here, we have examined the expression of matrix metalloproteinase-19 (MMP-19) in human cutaneous wounds and by human skin fibroblasts in culture. Expression of MMP-19 was detected by immunohistochemistry in fibroblasts, capillary endothelial cells, and macrophages in the dermal layer of large granulating wounds, as well as in chronic venous and decubitus ulcers. MMP-19 mRNA expression and pro-MMP-19 production by dermal fibroblasts in culture was potently enhanced by tumor necrosis factor-alpha (TNF-alpha). Induction of MMP-19 expression by TNF-alpha was prevented partially by blocking the activation of extracellular signal-regulated kinase (ERK)-1/2 by PD98059 and p38 activity by SB203580. Activation of ERK1/2 by adenovirus-mediated delivery of constitutively active MAPK/ERK kinase 1 resulted in the induction of MMP-19 expression. Activation of p38 alone by adenovirally delivered constitutively active MAPK kinase 3b (MKK3b) and MKK6b also enhanced MMP-19 production, and the most potent induction of MMP-19 expression was noted when ERK1/2 was activated in combination with p38. Activation of c-Jun N-terminal kinase (NK). Abundant pro-MMP-19 production by fibroblasts was associated with proteolytic processing of secreted pro-MMP-19. These results suggest a role of MMP-19 in cutaneous wound repair and identify three distinct signaling pathways, which coordinately mediate induction of MMP-19 expression in fibroblasts: mitogen-activated ERK1/2 pathway and stress-activated JNK and p38 pathways, of which control proteolytic activity of dermal fibroblasts.

Cells, Cultured↗
PubMed2003

New prognostic factors and developing therapy of cutaneous melanoma.

The multiple molecular alterations underlying the neoplastic process and clinical characteristics of cutaneous melanoma are currently under intensive investigation. Recent studies have demonstrated that the levels of melanoma-associated proteins in tumor tissue or in patient serum can serve as new markers to predict disease outcome. Similarly, the expression of thousands of genes in melanoma tumors can be surveyed simultaneously using DNA arrays, allowing molecular profiling of individual tumors, which gives the possibility of classifying melanomas based on their biological diversity. Large clinical studies have also identified multiple prognostic factors, such as tumor ulceration, and led to development of a new, more precise melanoma staging system, which emphasizes the biological characteristics of the primary disease. These new findings may have an important role in earlier measurement of the clinical response and provide a basis for tailored melanoma therapy, the development of which will also be discussed in this review.

Antigens, Neoplasm↗