Progelatinase A mRNA expression in cell lines derived from tumors in patients with metastatic renal cell carcinoma correlates inversely with survival

Characterization of genetically defined sporadic and hereditary type 1 papillary renal cell carcinoma cell lines

Renal cell carcinoma (RCC) is not a single disease but is made up of several different histologically defined subtypes that are associated with distinct genetic alterations which require subtype specific management and treatment. Papillary renal cell carcinoma (pRCC) is the second most common subtype after conventional/clear cell RCC (ccRCC), representing ~20% of cases, and is subcategorized into type 1 and type 2 pRCC. It is important for preclinical studies to have cell lines that accurately represent each specific RCC subtype. This study characterizes seven cell lines derived from both primary and metastatic sites of type 1 pRCC, including the first cell line derived from a hereditary papillary renal carcinoma (HPRC)-associated tumor. Complete or partial gain of chromosome 7 was observed in all cell lines and other common gains of chromosomes 16, 17, or 20 were seen in several cell lines. Activating mutations of MET were present in three cell lines that all demonstrated increased MET phosphorylation in response to HGF and abrogation of MET phosphorylation in response to MET inhibitors. CDKN2A loss due to mutation or gene deletion, associated with poor outcomes in type 1 pRCC patients, was observed in all cell line models. Six cell lines formed tumor xenografts in athymic nude mice and thus provide in vivo models of type 1 pRCC. These type 1 pRCC cell lines provide a comprehensive representation of the genetic alterations associated with pRCC that will give insight into the biology of this disease and be ideal preclinical models for therapeutic studies.

Cancer-Specific Survival Stratification Derived from Tumor Expression of Tissue Inhibitor of Metalloproteinase-2 in Non-Metastatic Renal Cell Carcinoma

Degradation of the extracellular matrix is a prerequisite for the processes of cancer cell invasion and metastasis. The purpose of our study was to assess the association of matrix metalloproteinases (MMP-1, MMP-2, MMP-3, MMP-9) and their inhibitors (TIMP-1 and TIMP-2) with renal cell carcinoma (RCC) progression and cancer-specific survival (CSS), using immunohistochemical analysis of 60 formalin-fixed, paraffin-embedded sections of tumor tissue and normal tissue near the tumor from surgical T1-3bN0 M0 RCC specimens. Significant overexpression of MMP-2 in tumor and normal tissue was correlated with advanced stages, tumor size, sarcomatous differentiation and clinical symptoms. Overall survival was 31.7% (55.2% M0, 9.7% M1) and CSS 56.7% (100% M0, 16.1% M1) with a follow-up of 76 (5-230) months. Fuhrman grade [HR 2.87 (95% CI: 1.28-6.45); p = 0.01], tumor size [HR 1.13 (95% CI: 1.03-1.26); p = 0.009] and low TIMP-2 expression [HR 0.35 (95% CI: 0.16-0.78); p = 0.01] were independent predictive factors of CSS and stratified the patients into three groups with different rates of 10-year CSS; [100%, 73.9% and 20.5% for the good, intermediate and poor prognosis group respectively (p = 0.000006)] . This study offers strong evidence that TIMP-2 expression in tumor tissue may play a crucial role in progression and poor prognosis in human localized and locally advanced RCC.

Effect of culture at low oxygen tension on the expression of heat shock proteins in a panel of melanoma cell lines

OBJECTIVE

Tumours are commonly hypoxic and this can be associated with aggressive tumour type, metastasis and resistance to therapy. Heat shock proteins (hsps) are induced in response to hypoxia, provide cancer cells with protection against tumour-associated stressors and chaperone oncoproteins that drive tumour proliferation. This study examined the effect of different oxygen concentrations on the expression of hsps in melanoma cell lines.

METHODS

Melanoma cell lines were cultured in 2% and 20% O(2). Expression of Hsp90, Hsp70, Hsp60, Hsp40 and Hsp32 proteins were determined by flow cytometry.

RESULTS

Growth rates and viability were reduced in the majority of cell lines by culture in 2% O(2). Hsp expression was different in 2% compared to 20% O(2) and changes in Hsp90 expression correlated with cell line generation time (P<0.005) and viability (P<0.01). Greater total hsp expression correlated with improved viability in 2% but not 20% O(2) (P<0.05). Relative expression of the different hsps was consistent across cell lines and each correlated with the others (P = 0.0001) but not with Hsp32. Hsp expression was inversely correlated with cell line adhesion to laminin as well as collagen type IV and Breslow depth of the original primary tumour tissue (P<0.05), but not with Clark level or patient survival. All five hsps were identified on the cell surface.

CONCLUSION

Culture in 2% O(2) variably altered hsp expression in a panel of melanoma cell lines. Hsp expression was associated with certain cell line characteristics and clinical parameters of the originating tumour.

Effects of a KiSS-1 peptide, a metastasis suppressor gene, on the invasive ability of renal cell carcinoma cells through a modulation of a matrix metalloproteinase 2 expression

Although effects of a metastasis suppressor gene, KiSS-1, have been postulated to be mediated by its receptor, hOT7T175, the mechanism of such effects remains unknown. This study was designed to evaluate the mechanism of how KiSS-1 works and to assess effects of a synthesized truncated KiSS-1 protein on the invasive ability of renal cell carcinoma (RCC) cells. Four RCC cell lines, Caki-1, KU19-20, RSP and RSM, were investigated to determine mRNA expressions of KiSS-1, its receptor, hOT7T175, matrix metalloproteinases (MMPs) and MMP inhibitors. While all cell lines demonstrated hOT7T175 mRNA expressions, only Caki-1 had KiSS-1 transcripts. A synthesized truncated KiSS-1 peptide, metastin (45-54), produced a marked suppression of the invasive ability in KU19-20 cells, which were deficient for KiSS-1 transcripts, but not in Caki-1 cells. Metastin (45-54) also increased the ability of KU19-20 cells to attach to collagen 4. Both MMP-2 mRNA levels and protein production were significantly decreased only in KU19-20 cells by metastin (45-54). In conclusion, metastin (45-54) may have potential therapeutic use by suppressing the motility and invasive ability of RCC cells which possess hOT7T175 with either a negative expression or very low expression level of KiSS-1 through, at least in part, the down-regulation of MMP-2.

Clinicopathologic and prognostic significance of matrix metalloproteinases in rectal cancer

BACKGROUND AND AIMS

The aim of this study was to determine the prognostic role of matrix metalloproteinases in rectal cancer.

MATERIALS AND METHODS

Formalin-fixed and paraffin-embedded tissue sections of 94 rectal carcinomas were used for the immunohistochemical analysis of matrix metalloproteinases (MMP)-2, MMP-7, MT1-MMP, and tissue inhibitor of metalloproteinases (TIMP)-2. Inclusion criteria were sporadic rectal adenocarcinoma resected curatively (including total mesorectal excision), adjuvant radiochemotherapy in UICC stages II and III, and complete intra-institutional follow-up. Results of immunohistochemistry were correlated with clinical and histopathologic data from the prospective rectal cancer registry and prognosis. End points of the prognostic analysis were tumor progression caused by local and/or distant recurrence and 5-year survival (disease-free and overall). To assess prognostic significance, statistics included univariate and multivariate analysis (p<0.05 statistically significant).

RESULTS

Of the 94 rectal carcinomas, 35% (33/94) showed an epithelial MMP-2 expression, 77% (72/94) were MMP-2 positive in the stroma. Fifty-four percent (51/94) were MMP-7 positive, and 47% (46/94) were positive for both MT1-MMP and TIMP-2. The stromal MMP-2 staining pattern was correlated with the depth of invasion (pT status, p=0.006) with MMP-7 (p=0.016) and TIMP-2 expression (p=0.036). Positive expression of MMP-2 in tumor epithelium was correlated with MMP-7 (p=0.027), MT1-MMP (p=0.036), and TIMP-2 expression (p<0.0001). A positive staining pattern of MMP-7 was significantly correlated with depth of invasion and TIMP-2 (p<0.01). The positive staining pattern of MT1-MMP was correlated with epithelial MMP-2 (p=0.036), MMP-7 (p=0.004), and TIMP-2 expression (p=0.002). TIMP-2 immunoreactivity correlated with depth of invasion (p=0.013), epithelial MMP-2 (p<0.001), stromal MMP-2 (p=0.036), MMP-7 (p<0.001), and MT1-MMP (p=0.002). Neither pattern correlated with age, gender, tumor stage (UICC), grading, preoperative serum carcinoembryonic antigen (CEA) level, or nodal status (p>0.05). Within a mean follow-up of 46 months, tumor progression, caused by either local recurrence or distant metastasis, occurred in 14 patients (15.4%). There was no significant association between the MMP expression and the incidence of local and/or distant recurrence. In terms of survival, preoperative CEA level (disease-free 5-year survival 46% with increased CEA vs 70% with normal CEA, p=0.01; overall 5-year survival 43 vs 74%, p<0.01) and UICC stage were the only factors to be significantly related to 5-year survival by univariate analysis, whereas the metalloproteinases failed to show a significant association. In multivariate analysis, CEA and UICC stage were not identified as independent factors predictive of survival.

CONCLUSION

MMP-2, MMP-7, MT1-MMP, and TIMP-2 do not appear to be significant predictors of prognosis in a homogenous collective of curatively resected rectal adenocarcinomas.

Tumor cell invasion of von Hippel Lindau renal cell carcinoma cells is mediated by membrane type-1 matrix metalloproteinase

Background

Metastatic renal cell carcinoma (RCC) remains the leading cause of mortality in patients with clear cell RCC arising from mutations in the von Hippel Lindau (VHL) tumor suppressor. Successful RCC tumor suppression by VHL requires the negative regulation of hypoxia inducible factor alpha (HIF alpha) protein and its downstream targets. Thus, identification of HIF target genes responsible for RCC tumor progression will aid in the development of therapies for this disease. We previously identified membrane type-1 matrix metalloproteinase (MT1-MMP) as a transcriptional target of HIF-2alpha in RCC cells null for VHL and showed that MT1-MMP is overexpressed in these cells. MT1-MMP is a key regulator of tumor progression through its functions as a matrix-degrading enzyme, as well as its ability to cleave factors, such as adhesion molecules and other MMPs. The aim of this study was to investigate the contribution of MT1-MMP to the invasive potential of RCC cells using in vitro type I collagen degradation and invasion assays.

Results

We evaluated RCC cells wild-type (WT8) and null (pRc-9) for VHL for invasive characteristics and showed that the pRc-9 cells demonstrated a greater propensity for both invasion and degradation of a type I collagen matrix. Furthermore, overexpression of either HIF-2alpha or MT1-MMP in the poorly invasive cell line, WT8, promoted collagen degradation and invasion of these cells. Finally, using RNAi, we show that inhibition of MT1-MMP suppresses tumor cell invasion of RCC cells.

Conclusion

Our results suggest that MT1-MMP is a major mediator of tumor cell invasiveness and type I collagen degradation by VHL RCC cells that express either MT1-MMP or HIF-2alpha. As such, MT1-MMP may represent a novel target for anti-invasion therapy for this disease.

Gelatinases (MMP-2 and -9) and their natural inhibitors as prognostic indicators in solid cancers

Neoplastic growth and dissemination involve increased proteolytic activity that is able to escape the regulative elements. Matrix metalloproteinases (MMPs), particularly gelatinases A and B (MMP-2 and -9), play a role in tumor invasion and angiogenesis, and they participate in cancer progression in several neoplasias. The expression of tissue inhibitors of gelatinases, TIMPs-1 and -2, has also been shown to be associated with the clinical course in some cancers. The prognostic value of these markers, however, seems to vary a great deal in different neoplastic diseases. In this review, the impact of the gelatinases and their inhibitors on the clinical course in several solid cancers is evaluated based on the growing data from recent clinical studies. The clinical data most often explore the overexpression of mRNA or immunoreactive protein in tumor tissue, or measure the concentration of the circulating proteinase or its inhibitor in pretreatment or follow-up serum samples. The growing amount of recent clinical data suggests that the impact of gelatinases on treatment decisions should be tested in clinical trials.

Farnesyltransferase inhibitor SCH-66336 downregulates secretion of matrix proteinases and inhibits carcinoma cell migration

The ras oncogenes are among those most frequently found in human cancers. Blocking Ras farnesylation is a promising strategy for arresting cancer growth. Ras activates several signaling pathways with key roles in cellular proliferation, invasion, metastasis and angiogenesis. Furthermore, proteolytic activities of matrix proteinases such as urokinase-type plasminogen activator (uPA) and matrix metalloproteinases (MMPs) are regulated by Ras isoforms. Thus, we investigated the effects of SCH-66336, a farnesyltransferase inhibitor, on secretion of components of the plasminogen activation system as well as on the gelatinases MMP-2 and MMP-9, which play pivotal roles in matrix remodeling. SCH-66336 up to 5 microM did not significantly alter the viability of prostate (PC-3) and renal (Caki-1) cancer cells incubated in serum-depleted medium. SCH-66336 partly inhibited the processing of H-Ras, while levels of mature N-Ras and K-Ras remained unaffected. Under these noncytotoxic conditions, uPA and tPA levels were lowered in culture medium but raised in cell lysates, suggesting inhibition of trafficking pathways. In contrast, SCH-66336 had no effect on uPAR expression or on secreted PAI-1 levels. As expected, the reduction of uPA and tPA activities by SCH-66336 inhibited the conversion of plasminogen to plasmin by about 25% in PC-3 cells. SCH-66336 also inhibited the levels of secreted pro-MMP-2 and pro-MMP-9 as well as the release of their inhibitors TIMP-1 and TIMP-2. SCH-66336 decreased both the adhesion and even more so the migration of PC-3 cells on gelatin. Thus, SCH-66336 inhibited farnesylation in both cancer cell types, and H-Ras functions should be reduced by the drug. In addition, the lower levels of secreted proteinases in the presence of SCH-66336 suggest that reduced matrix remodeling and cell migration should occur in treated tumors.

A Phase I Study of Oral BMS-275291, a Novel Nonhydroxamate Sheddase-Sparing Matrix Metalloproteinase Inhibitor, in Patients with Advanced or Metastatic Cancer

PURPOSE

BMS-275291 is a novel broad-spectrum inhibitor of matrix metalloproteinase (MMPs) rationally designed to spare a class of closely related metalloproteinases known as sheddases. Inadvertent sheddase inhibition is hypothesized to play a role in the dose-limiting joint toxicities occurring with hydroxamate-based MMP inhibitors. This trial was conducted to establish the recommended phase II dose; determine safety, toxicity, and pharmacokinetics of BMS-275291; and to assess potential markers of sheddase activity [tumor necrosis factor-alpha (TNFalpha) release and TNFalpha-RII shedding].

EXPERIMENTAL DESIGN

This was an open label, single arm, phase I study conducted at two centers. Patients with advanced or metastatic cancer were treated with once-daily oral BMS-275291 at doses escalating from 600 to 2400 mg/day. Six to eight patients/dose level were to be studied with the recommended phase II dose level expanded to a total of 15 patients. Pharmacokinetic sampling was performed on days 1, 15, and 29 at 0, 0.5, 1, 2, 4, 6, 8, and 24 h after dosing. Radiological tumor assessment was performed every 8 weeks.

RESULTS

Forty-four evaluable patients were enrolled in this study with the most frequent tumor types being colorectal cancer and non-small cell lung cancer. Dose limiting toxicities were observed at 600 mg/day (one of eight patients with grade 3 transaminitis) and at 1200 mg/day (1 of 15 patients with grade 3 rash and grade 4 shortness of breath), both in the context of predisposing conditions. No dose-limiting toxicities occurred at 900, 1800, or 2400 mg/day. The most frequent adverse events considered possibly, probably, or definitely drug-related were joint toxicity (myalgia/arthralgia), rash, fatigue, headache, nausea, and taste change, all of which were mild, grade 1, grade 2, and not dose-limiting. No objective tumor responses were observed. Twelve of forty-four patients received treatment for 4+ months, six for 8+ months, three for >1 year. Desired trough levels of parent BMS-275291 were maintained with once daily dosing. The mean plasma concentration of parent BMS-275291 at trough exceeded the calculated in vitro IC(80) value for MMP-2 and IC(90) value for MMP-9 at the recommended phase II dose of 1200 mg/day. No major changes in serum concentrations of sheddase enzymatic products, TNFalpha or TNFalpha-RII, were observed.

CONCLUSIONS

BMS-275291 is a nonhydroxamate MMP inhibitor with a novel mercaptoacyl zinc-binding group. In this study, plasma concentrations of BMS-275291 continuously exceeded in vitro MMP IC(50) values without dose-limiting joint toxicity. In this refractory patient population, a suggestion of disease stabilization was observed in 12 patients. On the basis of preclinical, clinical, and pharmacokinetic data, the recommended phase II dose for future study is 1200 mg/day.

Increased Expression of Matrix Metalloproteinase 9 Correlates with Poor Prognostic Variables in Renal Cell Carcinoma

BACKGROUND

MMP2 and MMP9 are two gelatinolytic enzymes, which are key regulators of tumor invasion and metastasis. This study aimed to clarify the prognostic significance of MMP2 and MMP9 with particular regard to their transcript levels, enzymatic activities in renal cell carcinomas (RCCs).

MATERIALS AND METHODS

Through cDNA array, the differential expression of the MMP superfamily was evaluated in RCC. Various properties of MMP2 and MMP9 were quantified, in 178 patients with RCC, based on the Heidelberg classification. Of these, 145 cases including 16 fresh-frozen cases were available for MMP2 and MMP9 transcript level evaluation. In addition, gelatinolytic activity was assessed by zymography in 16 other fresh-frozen samples from new RCC cases.

RESULTS

MMP2, 9, 11, 14, and 16 were upregulated in the conventional RCC in comparison with the chromophobe RCC, whereas MMP1, 11 and 16 were pronounced in papillary RCC. MMP9 transcript levels were strongly associated with the MMP9 enzymatic activity (p=0.001), and therefore, with disease-free survival (p=0.001) and metastasis (p=0.011). Gelatinolytic activity of MMP9 by zymography was strongly associated with MMP9 mRNA expression, which was more intense in 'conventional' RCC than in 'chromophobe' RCC (p=0.001), irrespective of tumor grade or stage. MMP9 was proven to be a significant prognostic predictor by multi-variate survival analysis (p=0.0054). MMP2 enzymatic activity disappeared in spite of its constant transcript expression in RCC.

CONCLUSIONS

MMP9 appears to be regulated at the transcript level, whereas MMP2 is regulated at the posttranscriptional level. Poor survival with a high frequency of metastases in 'conventional' RCC is associated with MMP9, which exhibits a high transcriptional level, and a high gelatinolytic activity. As a result, MMP9 may be a candidate of predictors of disease-free survival in RCC.

Prognostic significance of matrix metalloproteinases-2 activation ratio in renal cell carcinoma

BACKGROUND

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases. MMP-2 and MMP-9 have been reported to be closely associated with tumor invasion and metastasis in various human carcinomas.

METHODS

Tissue samples were obtained from 57 patients with renal cell carcinoma (RCC) who underwent radical nephrectomy in our hospital. We examined the expression of MMPs by gelatin zymography and assessed correlations with clinico-pathological parameters and clinical outcomes.

RESULTS

We detected bands corresponding to MMP-9, proMMP-2 and active MMP-2. The expression of active MMP-2 and MMP-2 activation ratio (active MMP-2/[proMMP-2 and active MMP-2]) were higher in T3 tumors than in T1 and T2 tumors. There were no significant differences in the expression of proMMP-2, active MMP-2 or MMP-9 for any of the clinico-pathological parameters. Patients with high MMP-2 activation ratio or high MMP-9 had significantly worse cause-specific survival. Interestingly, among patients with stage III RCC, those with high MMP-2 activation ratio or high active MMP-2 had significantly worse cause-specific survival. Univariate analysis showed that histological grade (P = 0.0001), histologic type (P = 0.0005), MMP-2 activation ratio (P = 0.0159), stage (P = 0.0001), MMP-9 (P = 0.0316), and T (primary tumor) category of TNM (primary tumor, lymph node, metastasis) classification (P = 0.0021) were significant predictors of clinical outcome. Multivariate analysis showed that only histological grade (P = 0.002) and stage (P = 0.0099) were independently significant predictors of clinical outcome.

CONCLUSION

Activation of MMP-2 appears to play important roles in initiating metastasis, as shown by results obtained with stage III RCC patients. However, further study is needed to confirm this.

Angiogenesis in renal cell carcinoma: Evaluation of microvessel density, vascular endothelial growth factor and matrix metalloproteinases

BACKGROUND

Angiogenesis, the growth of new blood vessels, has a critical role in tumor growth and metastasis. The purpose of this study was to investigate the involvement of angiogenesis and angiogenic factors in the pathogenesis of renal cell carcinoma (RCC).

METHODS

Formalin-fixed and paraffin-embedded tissue blocks from 70 patients with RCC were studied. The situations of tumor angiogenesis were evaluated by assessing microvessel density (MVD) through CD31 immunostaining. The expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and metalloproteinase-9 (MMP-9) was detected immunohistochemically.

RESULTS

The value of MVD ranged from 12.0 to 93.0 with a median of 39.91 in RCC. Of the 70 RCCs, the expression of VEGF was detected in 52 (74.3%), MMP-2 in 29 (41.4%) and MMP-9 in 19 (27.1%) cases. Statistical analysis revealed significant associations of the tumor stage with MVD, and the expression of VEGF and MMP-2 in RCC. Additionally, MVD was closely related to the expression of VEGF but was not related to the expression of MMP-2 and MMP-9 in RCC.

CONCLUSION

The degree of angiogenesis may be closely related to the tumor progression of RCC. The expression of VEGF may be responsible for angiogenesis in RCC, and both VEGF and MMP-2 expression may function as tumor associated angiogenic factors in RCC.

Matrix metalloproteinases in cancer: prognostic markers and therapeutic targets

Degradation of extracellular matrix is crucial for malignant tumour 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 tumour tissue or serum of patients with advanced cancer and their role as prognostic indicators in cancer is studied. In addition, therapeutic intervention of tumour growth and invasion based on inhibition of MMP activity is under intensive investigation and several MMP inhibitors are in clinical trials in cancer. In this review, we discuss the current view on the feasibility of MMPs as prognostic markers and as targets for therapeutic intervention in cancer.

mRNA expression of matrix metalloproteases and their inhibitors differs in subtypes of renal cell carcinomas

Altered expression of matrix metalloproteases (MMPs) and their inhibitors, the tissue inhibitors of matrix metalloproteases (TIMPs), has been demonstrated in various tumour tissues. mRNA expression patterns of MMP-1, MMP-2, MMP-3, MMP-9, MMP-11, MMP-12, MMP-14 and TIMP-1, TIMP-2, TIMP-3 and TIMP-4 were evaluated by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in 30 renal cell carcinomas (RCC), as well as in the surrounding tissues. Expression of the MMPs was significantly stronger in the carcinomas than in non-malignant tissues. High levels were demonstrated particularly in clear cell RCCs (CC-RCC). Except for MMP-1, MMP expression in the papillary RCCs (P-RCC) was, for most MMPs, significantly lower. Expression of the TIMPs in malignant cells of both subtypes was weak, with the exception of TIMP-4 which was strongly expressed in the P-RCCs and downregulated in the CC-RCCs. The latter was correlated with chromosomal loss of 3p, harbouring the TIMP-4 gene locus. In conclusion, deregulated expression of the MMPs and TIMPs in RCCs differs according to histology, grade, size and cytogenetic characteristics, suggesting that MMP and TIMP expression patterns play an important role for the typical histomorphological features of RCC subtypes and their respective biological behaviour.

Matrix-metalloproteinases and their inhibitors in plasma and tumor tissue of patients with renal cell carcinoma

Matrix-metalloproteinases (MMPs) are associated with invasive and metastatic behavior of several human malignant tumors. We have determined MMP-2 and MMP-9 and tissue inhibitors of MMPs (TIMP-1 and TIMP-2) in blood plasma and in renal tissue samples of patients with renal cell carcinoma (RCC) from cancerous and non-cancerous parts of the same kidney. In tumor tissue, MMP-9 and TIMP-1 were significantly higher than in normal counterparts. MMP-2 was not different between tumor tissue and normal counterparts. TIMP-2 values could not be measured. In plasma, MMP-9 concentrations were significantly higher in RCC patients than in healthy controls, MMP-2 and TIMP-2 concentrations were higher in healthy controls and TIMP-1 concentrations were not different.

The von Hippel-Lindau tumor suppressor gene inhibits hepatocyte growth factor/scatter factor-induced invasion and branching morphogenesis in renal carcinoma cells

Loss of function in the von Hippel-Lindau (VHL) tumor suppressor gene occurs in familial and most sporadic renal cell carcinomas (RCCs). VHL has been linked to the regulation of cell cycle cessation (G(0)) and to control of expression of various mRNAs such as for vascular endothelial growth factor. RCC cells express the Met receptor tyrosine kinase, and Met mediates invasion and branching morphogenesis in many cell types in response to hepatocyte growth factor/scatter factor (HGF/SF). We examined the HGF/SF responsiveness of RCC cells containing endogenous mutated (mut) forms of the VHL protein (VHL-negative RCC) with that of isogenic cells expressing exogenous wild-type (wt) VHL (VHL-positive RCC). We found that VHL-negative 786-0 and UOK-101 RCC cells were highly invasive through growth factor-reduced (GFR) Matrigel-coated filters and exhibited an extensive branching morphogenesis phenotype in response to HGF/SF in the three-dimensional (3D) GFR Matrigel cultures. In contrast, the phenotypes of A498 VHL-negative RCC cells were weaker, and isogenic RCC cells ectopically expressing wt VHL did not respond at all. We found that all VHL-negative RCC cells expressed reduced levels of tissue inhibitor of metalloproteinase 2 (TIMP-2) relative to the wt VHL-positive cells, implicating VHL in the regulation of this molecule. However, consistent with the more invasive phenotype of the 786-0 and UOK-101 VHL-negative RCC cells, the levels of TIMP-1 and TIMP-2 were reduced and levels of the matrix metalloproteinases 2 and 9 were elevated compared to the noninvasive VHL-positive RCC cells. Moreover, recombinant TIMPs completely blocked HGF/SF-mediated branching morphogenesis, while neutralizing antibodies to the TIMPs stimulated HGF/SF-mediated invasion in vitro. Thus, the loss of the VHL tumor suppressor gene is central to changes that control tissue invasiveness, and a more invasive phenotype requires additional genetic changes seen in some but not all RCC lines. These studies also demonstrate a synergy between the loss of VHL function and Met signaling.