Invasion Of Renal Cancer Cells Research Articles

Pharmacological Inhibitor of Fatty Acid Synthase Suppresses Growth and Invasiveness of Renal Cancer Cells

Fatty acid synthase has been shown to be over expressed in a wide range of cancers and it has emerged as a therapeutic target. We examined whether fatty acid synthase could be a novel therapeutic target for renal cell carcinoma using the pharmacological fatty acid synthase inhibitor C75 (Cayman Chemical, Ann Arbor, Michigan). The effects of C75 on cell viability and proliferation in human renal cancer 769P (ATCC(R)), Caki-1 and KU20-01 cells were examined by MTS assay and cell counts. Cell cycle distribution was analyzed by flow cytometry and cell invasiveness was assessed by wound healing and Matrigel(trade mark) invasion assays. Fatty acid synthase expression and the effects of C75 on intracellular signaling pathways were analyzed by Western blotting. The antitumor efficacy of C75 was examined using Caki-1 cell xenografts. All renal cancer cell lines expressed detectable fatty acid synthase. C75 (10 mug/ml) significantly inhibited cell viability and growth by arresting the cell cycle at the G2/M phase and inducing apoptosis (p <0.01). The covered area in the wound and the number of cells invading through a Matrigel chamber were significantly smaller for cells treated with C75 than they were for control cells treated with vehicle (p <0.001). C75 suppressed Her2 and epidermal growth factor receptor expression as well as STAT3 phosphorylation, while increasing p53 and p21(Waf1/Cip1) expression. Intraperitoneal administration of C75 at doses of 20 mg/kg per week for 28 days significantly reduced the tumor volume of Caki-1 xenografts (p <0.05). Pharmacological inhibition of fatty acid synthase could be an effective strategy for treating renal cell carcinoma.

Expression of Matrix Metalloproteinase-10 in Renal Cell Carcinoma and Its Prognostic Role

ObjectivesMatrix metalloproteinase (MMP)-10 is associated with malignant aggressiveness in various cancers, but its importance has not been investigated in conventional renal cell carcinoma (CRCC). The purpose of this study was to determine the clinical significance and malignant potential of MMP-10 in human CRCC tissues. Patients and methodsSpecimens were obtained from 103 CRCC patients who underwent radical surgery and were examined by immunohistochemistry for MMP-10 expression. The proportions of Ki-67–stained cells (proliferation index: PI) and densities of CD34-positive vessels (microvessel density: MVD) were measured by a computer-aided image analysis system. The relationships between MMP-10 expression and clinicopathologic features and various parameters including tumour size, PI, MVD, and survival were investigated by univariate and multivariate analyses. ResultsMMP-10 expression was mainly detected in cancer cell cytoplasm, and 45 (43.7%) CRCCs were considered MMP-10–positive. MMP-10 expression correlated with grade (p=0.006) and pT stage (p<0.001), and it was a significant and independent factor for high pT stage in multivariate analysis model. MMP-10 expression was associated with MVD (p=0.022) but not tumour size or PI. MMP-10 expression in CRCC was a significant predictor of poor outcome by log-rank test (p=0.013) but not by multivariate analysis. ConclusionsMMP-10 seems to play an important role in renal cancer cell invasion and is a potentially useful therapeutic target to prevent CRCC tumour progression.

Anticancer effect of lysine, proline, arginine, ascorbic acid and green tea extract on human renal adenocarcinoma line 786-0

Five-year survival is limited to 60% in renal cancer patients at diagnosis. Due to the cancer's resistance to conventional treatments and associated high morbidity, we investigated the antimetastatic effects of a specific nutrient mixture (NM) containing lysine, proline, arginine, ascorbic acid and green tea extract on human renal adenocarcinoma cell line 786-0 by measuring: cell proliferation, modulation of MMP-2 and -9 secretion, and cancer cell invasive potential. Human renal cancer cell line 786-0 (ATCC) was grown in RPMI medium in 24-well tissue culture plates. At near confluence, the cells were treated with NM, dissolved in media, and tested at 0, 10, 50, 100, 500 and 1000 microg/ml in triplicate at each dose. Cells were also treated with PMA 200 ng/ml to study enhanced MMP-9 activity. Cell proliferation was evaluated by MTT assay, MMP secretion by gelatinase zymography, and invasion through Matrigel. Zymography demonstrated MMP-2 and MMP-9 secretion by uninduced renal cancer cells with enhanced MMP-9 induced by PMA (200 ng/ml) treatment. NM inhibited the secretion of both MMPs in a dose-dependent fashion with virtual total inhibition of MMP-2 at 500-microg/ml concentration and MMP-9 at 100 microg/ml. The invasion of renal cancer cells through Matrigel was totally inhibited (p=0.0001) by NM at 1000 microg/ml concentration. Our results support a potential role for the nutrient mixture tested in the treatment of renal cell carcinoma, by inhibition of MMP-2 and MMP-9 secretion and invasion.

Leptin Promotes Invasiveness of Murine Renal Cancer Cells Via Extracellular Signal-Regulated Kinases and Rho Dependent Pathway

Obesity is a significant risk factor for renal cell carcinoma. The adipocyte derived cytokine leptin, which controls body weight homeostasis through food intake and energy expenditure, recently provided a potential link between obesity and cancer development. We examined whether leptin promotes the invasiveness of renal cancer cells and we investigated its underlying signaling pathway. Leptin receptor expression in the 6 human renal cancer cell lines Caki-1, ACHN, 769P, A498, SKRC44 and SKRC49, and in the murine renal cancer cell line Renca was examined by reverse transcriptase-polymerase chain reaction and Western blotting. The effect of leptin on renal cancer cell invasiveness was assessed by the invasion of cells through Matrigel coated Transwell inserts. Leptin induced intracellular signaling was examined by Western blotting. Leptin receptor was detected in all renal cancer cells examined at the mRNA and protein levels. Leptin increased Renca cell invasiveness at 1 ng/ml (p < 0.05). There was up to 3-fold invasiveness compared to untreated cells at 100 ng/ml with the activation of extracellular signal-regulated kinases and rho guanosine triphosphatase (p < 0.01). Leptin induced activation of rho guanosine triphosphatase was inhibited not only by the rho kinase inhibitor Y27632, but also by the MEK1 inhibitor PD98059, of which each inhibited leptin induced invasion of Renca cells (p < 0.01). Leptin promoted the invasiveness of murine renal cancer cells via extracellular signal-regulated kinases and rho guanosine triphosphatase dependent pathways. Rho guanosine triphosphatase was a downstream effector of extracellular signal-regulated kinases in leptin induced invasion. Leptin signaling could have a key role in renal cell carcinoma invasion.

Von Hippel-Lindau tumor suppressor protein stimulation by thrombin involves RhoA activation.

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is associated with the development of vascular tumors including renal cell carcinoma. Aside from the role played by the VHL protein (pVHL) in negative regulation of hypoxia-inducible factor, 41F-1alpha, pVHL also takes part in cytoskeletal organization. Thrombin is a serine protease involved in angiogenesis and in cancer progression and its action is mediated by the protease-activated receptors (PARs). In several cell types, thrombin induces reorganization of the cytoskeleton along with RhoA activation. Thus, we conducted an investigation on the capacity of thrombin to regulate pVHL expression. Our results demonstrated that VHL mRNA and protein levels were increased by thrombin in cultured renal cancer cells. Cytoplasmic pVHL was redistributed to perinuclear regions and membrane fractions following thrombin treatments. Stimulation of Caki-1 cells with PAR1, PAR2 and PAR4 agonist peptides demonstrated that PAR1 was the receptor involved in thrombin-induced pVHL expression. Western blot analysis confirmed that these cells express PAR1 and that its expression was increased by thrombin. PAR1 activation by both thrombin and an agonist peptide stimulated renal cancer cell invasion through Matrigel. Interestingly, the upregulation of pVHL was dependent on RhoA because C3 exotoxin abolished pVHL induction. However, the pharmacological Rho kinase inhibitor, Y27632, did not influence pVHL expression in the presence of thrombin, suggesting that other RhoA effectors were involved in the process. Together, these results demonstrate that thrombin induces both pVHL expression via PAR1/RhoA activation as well as the stimulation of renal cancer cell invasion suggesting a role for thrombin in tumor invasion.

Differential inhibition of renal cancer cell invasion mediated by fibronectin, collagen IV and laminin

Invasion of tumor cells into the extracellular matrix is an essential step in the formation of metastases in renal cancer. Cell adhesion molecules such as β 1-integrins, which bind to the RGD sequence (arginine-glycine-asparagine) and CD44 are involved in this process. We examined the invasion of a renal carcinoma cell line (CCF-RC1) into the extracellular matrix compounds fibronectin, collagen IV and laminin and the effect of TGFβ and IFNγ on this process. The inhibitory effect of an antibody against the β 1-subunit of integrins (CD29), as well as a pentapeptide including the RGD sequence, was also evaluated. A micro-chemotaxis chamber, including a polycarbonate membrane with a pore diameter of 8 μm, was used for quantification of cell migration. The addition of the extracellular matrix compounds fibronectin, laminin and collagen IV resulted in a 5–10-fold increase in invasion. This increased invasion depends strongly on the presence of β 1-integrins, shown by the use of an antibody against CD29 or a RGD including peptide which inhibit the cell migration by approximately 88%. CD44 is less involved in collagen IV dependent migration and almost no influence of CD44 was observed on a fibronectin and laminin dependent migration. TNFα and IFNγ did not significantly influence the expression of CD29 or CD44, and no alteration in tumor cell migration was observed. These results show that the invasion of renal cancer cells is differentially regulated by compounds of the extracellular matrix, whereby fibronectin seems to be the most critical factor. The molecular interactions in this process are strongly dependent on β 1-integrins and the corresponding amino acid sequence RGD.

Carbonic anhydrase inhibitor suppresses invasion of renal cancer cells in vitro.

Acidification of the extracellular milieu of malignant tumors is reported to increase the invasive behavior of cancer cells. In normal tissues, production of acid is catalyzed by carbonic anhydrases (CAs), some of which are known to be overexpressed in certain cancers. To investigate the functional role of CA activity in such cancer cells, we analyzed the effect of acetazolamide, a potent CA inhibitor, on the invasive capacity of four renal carcinoma cell lines (Caki-1, Caki-2, ACHN, and A-498). We found that 10 microM acetazolamide inhibited the relative invasion rate of these cell lines between 18-74%. The Caki-2 and ACHN cell lines displayed the highest responsiveness, and their responses clearly depended on the acetazolamide concentration in the culture medium. Immunocytochemical and Western blotting results identified the presence of CA isoenzyme II in the cytoplasm of all four cell lines and CA XII on the plasma membrane in three of four cell lines. Because acetazolamide alone reduced invasiveness of these cancer cells in vitro, we conclude that the CAs overexpressed in these renal cancer cells contribute to invasiveness, at least in vitro, and suggest that CA inhibitors may also reduce invasiveness in other tumors that overexpress one or more CAs.