Expression of gelatinase/type IV collagenase in tumor necrosis correlates with cell detachment and tumor invasion

Effects of a nutrient mixture on immunohistochemical localization of cancer markers in human cervical cancer HeLa cell tumor xenografts in female nude mice

Although fully treatable in the early stages, once cervical cancer has metastasized, patient outcome is poor. The main objective of this study was to examine the effect of dietary supplementation with a nutrient mixture (NM) containing lysine, ascorbic acid, proline, green tea extract and other micronutrients on HeLa cell xenografts in nude female mice. Tumor growth was measured and immunohistochemical staining was evaluated for the following cancer markers: Ki67 (proliferation); matrix metalloproteinase (MMP)-2 and -9 (invasion/metastasis); vascular endothelial growth factor (VEGF) (angiogenesis); terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and B-cell lymphoma 2 (Bcl-2) (apoptosis); cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) (inflammation); and glutathione S-transferase π (GSTπ) (a general cancer marker). Following housing for a week, 5/6-week-old female athymic nude mice (n=12) were inoculated subcutaneously with 3×10⁶ HeLa cells in 0.2 ml phosphate-buffered saline and 0.1 ml Matrigel™ and randomly divided into two groups; control group mice were fed regular mouse chow and NM group mice the regular diet supplemented with 0.5% NM (w/w). After four weeks, the mice were sacrificed and their tumors were excised and processed for histology. The NM strongly inhibited the growth of HeLa xenografts in nude mice. The mean tumor weight was reduced to 59% (P=0.001) in the mice fed the NM compared with the tumor weight in the controlled diet mice. Ki67, MMP-2 and -9, VEGF, TUNEL, Bcl-2, COX-2, iNOS and GSTπ all showed a lower intensity and frequency of staining in the NM group compared with that in the control group. In conclusion, NM supplementation strongly inhibited tumor growth and cancer markers in female nude mice injected with HeLa xenografts.

In vitro and in vivo effects of a nutrient mixture on breast cancer progression

Long-term survival of patients with breast cancer remains poor, due to metastasis and recurrence. We investigated the effects of a novel nutrient mixture (NM) containing ascorbic acid, lysine, proline and green tea extract in vitro and in vivo on 4T1 murine breast cancer, a representative model for metastatic breast cancer. After one week of isolation, 5-6-week-old female Balb/C mice were inoculated with 5x10⁵ 4T1 cells into the mammary pad and randomly divided into two groups; the control group was fed a regular diet and the NM group a regular diet supplemented with 0.5% NM. After four weeks, the mice were sacrificed and their tumors, lungs, livers, kidneys, hearts and spleens were excised and processed for histology. Dimensions (length and width) of tumors were measured using a digital caliper, and the tumor burden was calculated using the following formula: 0.5 x length x width. We also tested the effect of NM in vitro on 4T1 cells, measuring cell proliferation by MTT assay, MMP secretion by zymography, invasion through Matrigel, migration by scratch test and morphology by H&E staining. NM inhibited tumor weight and burden of 4T1 tumors by 50% (p=0.02) and 53.4% (p≤0.0001), respectively. Lung metastasis was profoundly inhibited by NM supplementation: mean number of colonies was reduced by 87% (p<0.0001) and mean weight of lungs by 60% (p=0.0001) compared to control mice. Metastasis to liver, spleen, kidney and heart was significantly reduced with NM supplementation. In vitro, NM exhibited 50% toxicity over the control at 250 and 500 µg/ml concentrations. Zymography demonstrated MMP-2 and MMP-9 secretion which was inhibited by NM in a dose-dependent manner, with virtual total inhibition of both at 1,000 µg/ml. Migration by scratch test and invasion through Matrigel were inhibited in a dose-dependent manner with total block of invasion at 250 and of migration at 1,000 µg/ml. These results suggest that NM has therapeutic potential in the treatment of breast cancer.

Ascorbate supplementation inhibits growth and metastasis of B16FO melanoma and 4T1 breast cancer cells in vitamin C-deficient mice

Degradation of the extracellular matrix (ECM) plays a critical role in the formation of tumors and metastasis and has been found to correlate with the aggressiveness of tumor growth and invasiveness of cancer. Ascorbic acid, which is known to be essential for the structural integrity of the intercellular matrix, is not produced by humans and must be obtained from the diet. Cancer patients have been shown to have very low reserves of ascorbic acid. Our main objective was to determine the effect of ascorbate supplementation on metastasis, tumor growth and tumor immunohistochemistry in mice unable to synthesize ascorbic acid [gulonolactone oxidase (gulo) knockout (KO)] when challenged with B16FO melanoma or 4T1 breast cancer cells. Gulo KO female mice 36-38 weeks of age were deprived of or maintained on ascorbate in food and water for 4 weeks prior to and 2 weeks post intraperitoneal (IP) injection of 5×10⁵ B16FO murine melanoma cells or to injection of 5×10⁵ 4T1 breast cancer cells into the mammary pad of mice. Ascorbate-supplemented gulo KO mice injected with B16FO melanoma cells demonstrated significant reduction (by 71%, p=0.005) in tumor metastasis compared to gulo KO mice on the control diet. The mean tumor weight in ascorbate supplemented mice injected with 4T1 cells was reduced by 28% compared to tumor weight in scorbutic mice. Scorbutic tumors demonstrated large dark cores, associated with increased necrotic areas and breaches to the tumor surface, apoptosis and matrix metalloproteinase-9 (MMP-9), and weak, disorganized or missing collagen I tumor capsule. In contrast, the ascorbate-supplemented group tumors had smaller fainter colored cores and confined areas of necrosis/apoptosis with no breaches from the core to the outside of the tumor and a robust collagen I tumor capsule. In both studies, ascorbate supplementation of gulo KO mice resulted in profoundly decreased serum inflammatory cytokine interleukin (IL)-6 (99% decrease, p=0.01 in the B16F0 study and 85% decrease, p=0.08 in the 4T1 study) compared to the levels in gulo KO mice deprived of ascorbate. In the B16FO study, ascorbate supplementation of gulo KO mice resulted in profoundly decreased serum VEGF (98% decrease, p=0.019 than in the scorbutic gulo KO mice). As expected, mean serum ascorbate level in ascorbate-restricted mice was 2% (p<0.001) of the mean ascorbate levels in supplemented mice. In conclusion, ascorbate supplementation hinders metastasis, tumor growth and inflammatory cytokine secretion as well as enhanced encapsulation of tumors elicited by melanoma and breast cancer cell challenge in gulo KO mice.

Bacoside A downregulates matrix metalloproteinases 2 and 9 in DEN-induced hepatocellular carcinoma

Cancer metastasis is a complex multi-step process, responsible for a majority of cancer-related deaths by affecting the critical organs and causing complications in therapies. Hepatocellular carcinoma is a multi-factorial disease and is the third most common cause of cancer related mortality worldwide. Clinical and experimental studies have shown that MMP-2 and MMP-9 are involved in tumor invasion and metastases and their elevated expression has been associated with poor prognosis. Our recent studies showed a strong anti-oxidant and hepatoprotective effects of bacoside A (BA) against carcinogen. Nevertheless the effect of BA on the activities and expression of MMP-2 and MMP-9 during hepatocellular carcinoma is not yet recognized. Therefore, the present study was designed to assess the same. Results of gelatin zymography study showed that BA co-treatment significantly decreased the activities of MMP-2 and MMP-9, which is increased during hepatocellular carcinoma. Further immunoblot analysis showed decreased expression of MMP-2 and MMP-9 in rats co-treated with BA compared to DEN-induced hepatocellular carcinoma. Our results reveal that BA exerts its anti-metastatic effect against DEN-induced hepatocellular carcinoma by inhibiting the activities and expressions of MMP-2 and MMP-9.

Matrix metalloproteinase-9 silencing by RNA interference triggers the migratory-adhesive switch in Ewing's sarcoma cells

Enhanced expression of (pro)matrix metalloproteinase-9 (MMP-9) is associated with human tumor invasion and/or metastasis. COH cells derived from a highly invasive and metastatic Ewing's sarcoma constitutively express proMMP-9. Transfection of a double stranded RNA that targets the MMP-9 mRNA into COH cells depleted the corresponding mRNA and protein as demonstrated by reverse transcriptase-PCR, enzyme-linked immunosorbent assay, and gelatin zymography. proMMP-9 extinction resulted in the following: (i) decreased spreading on extracellular matrix (fibronectin, laminin, collagen IV)-coated surfaces, (ii) inhibition of migration toward fibronectin, and (iii) induced aggregation, which was specifically disrupted by a function-blocking E-cadherin antibody. MMP-9 knockdown concomitantly resulted in increased levels of surface E-cadherin, redistribution at the plasma membrane of beta-catenin, and its physical association with E-cadherin. Moreover, induction of E-cadherin-mediated adhesion was associated with RhoA activation and changes in paxillin cytoskeleton. Finally, an inhibitor of gelatinolytic activity of pro-MMP9 did not reduce COH cell migration confirming that the enzymatic property of COH MMP-9 was not required for migration toward fibronectin. Overall, our observations define a novel critical role for proMMP-9 in providing a cellular switch between stationary and migratory cell phases.

Verapamil inhibits tumor protease production, local invasion and metastasis development in murine carcinoma cells

The invasion and metastasis process involves degradation of the extracellular matrix mediated by tumor- and host-produced proteolytic enzymes. The main enzymes involved in this process are urokinase-type plasminogen activator (uPA) and the matrix metalloproteinases (MMPs). Calcium is a main co-factor in the signaling pathways that regulate cell proliferation and protease production. We have studied here the effect of verapamil, a calcium channel blocker widely used to treat hypertensive diseases, on local tumor growth, spontaneous and experimental metastasis development, tumor-associated protease production and circulating MMP activity in tumor-bearing mice. BALB/c mice treated for 45 days with verapamil showed no toxic effects. Oral administration of verapamil to mice injected with F311 tumor cells, either pre-treated or not with verapamil, showed a significant decrease of local tumor invasion and both spontaneous and experimental metastasis development (51.3% inhibition of metastasis in both cases, p < 0.01). uPA and MMP-9 production by tumor cells in vitro was significantly inhibited by verapamil in a dose-dependent manner, showing a long-term inhibition after removal of the drug. Verapamil also exhibited a marked cytostatic effect on F311 cell proliferation in vitro. In addition, circulating MMP activity, usually enhanced in tumor-bearing mice, diminished significantly with all verapamil treatments. Our results suggest that modulation of the calcium-dependent signaling pathways that regulate tumor- or host-dependent production of proteases and tumor cell proliferation could contribute to the inhibition of metastasis development. Finally, we describe the inhibitory effects of a commonly used hypotensor in humans, verapamil, on the invasive and metastatic capacity of mammary tumor cells.

Production of trypsins by human gastric cancer cells correlates with their malignant phenotype

Proteolytic degradation of extracellular matrix is a critical step in tumour invasion and metastasis. To examine the role of trypsin in tumour dissemination, we cloned two variants (S4 and R3 cells) from STKM-1, a trypsinogen 1-producing diffuse gastric cancer cell line. Western blot analysis with antitrypsin antibody showed that 26 and 24 kDa proteins were highly detected in S4 conditioned medium (CM) in comparison to R3 CM. In addition to the 26 and 24 kDa proteins, 25 and 23 kDa bands, which correspond to enterokinase-activated trypsin, were found only in S4 CM. When the CMs of the two clones were treated with enterokinase, the 25 and 23 kDa trypsin activities in S4 CM were effectively increased as compared with R3 CM. When the two clones were inoculated intraperitoneally (i.p.) into nude mice, S4 cells strongly invaded the liver, pancreas and peritoneum and killed the hosts more rapidly than R3 cells: the 50% survival time was 50 days for S4 and 82 days for R3 cells. These results suggest that trypsin production is associated with the invasive growth of STKM-1 gastric cancer cells.

Chromosome 14 alteration is associated with increased collagenase expression and the metastatic potential of murine melanomas

The purpose of this study was to correlate abnormalities in chromosome 14 with the invasive metastatic phenotype of K-1735 murine melanoma cells. Low metastatic K-1735 clone 10 and clone 23 cells were transfected with either basic fibroblast growth factor (bFGF), Kaposi's fibroblast growth factor (kFGF), or c-H-ras gene. A high number of bFGF- and H-ras-transfected cells exhibited chromosome 14 rearrangements. These cells also had increased expression of collagenase IV. The kFGF-transfected cells were highly metastatic but did not have increased expression of collagenase type IV. The kFGF-transfected cells were highly metastatic but did not have increased expression of collagenase type IV, nor abnormalities in chromosome 14. The data imply that karyotypic changes in chromosome 14 are associated with increase expression of collagenase type IV.

Exposure to vinorelbine inhibits in vitro proliferation and invasiveness of transitional cell bladder carcinoma

PURPOSE

To study the effect of vinorelbine (VNR) on in vitro cell proliferation, invasiveness, cell adhesion to substrate, cell motility and metalloproteinase secretion of MB-49, a murine transitional cell carcinoma of the bladder (TCC).

MATERIALS AND METHODS

The colorimetric MTS assay, which depends upon viable versus nonviable mitochondria, was used to evaluate the effect of graded concentrations of VNR on in vitro MB-49 cell growth. Chemoinvasion and cell motility were studied in TCC cells exposed for 24 hours to a noncytotoxic dose of VNR, through their ability to migrate across Matrigel-coated or Type IV collagen-coated 8-microns. pore filters. Zymographic studies in gelatin-embedded polyacrylamide gels were done to investigate gelatinolytic activity in conditioned media from treated and untreated MB-49 cells.

RESULTS

Vinorelbine inhibited MB-49 cell growth in a dose-dependent manner (IC(50)40 ng./ml.). In vitro cell invasive capacity of MB-49 cells pretreated for 24 hours with VNR at noncytotoxic doses (1 and 10 ng./ml.) was significantly lower than that of untreated cells. The decreased invasion of VNR-treated cells was not accompanied by a diminished adhesion to Matrigel or type IV collagen nor by a significant reduced secretion of gelatinolytic metalloproteinases. Instead, motility of MB-49 cells exposed to noncytotoxic concentrations of VNR was inhibited in a dose-response fashion similar to that of invasion.

CONCLUSION

Vinorelbine proved to be an effective drug to inhibit tumor cell growth and invasion in a transitional cell bladder carcinoma model. The results obtained would justify preclinical studies to evaluate the effectiveness of VNR as a potential treatment of TCC.

Adhesion molecules and their role in cancer metastasis

This article describes various adhesion molecules and reviews evidence to support a mechanistic role for adhesion molecules in the process of cancer metastasis. A variety of evidence supports the involvement of specific adhesion molecules in metastasis. 1. For example, some cancer cells metastasize to specific organs, irrespective of the first organ encountered by the circulating cancer cells. This ability to colonize a specific organ has been correlated with the preferential adhesion of the cancer cells to endothelial cells derived from the target organ. This suggests that cancer cell/endothelial cell adhesion is involved in cancer cell metastasis and that adhesion molecules are expressed on the endothelium in an organ-specific manner. 2. Further, inclusion of peptides that inhibit cell adhesion, such as the YIGSR- or RGD-containing peptides, is capable of inhibiting experimental metastasis. 3. Metastasis can be enhanced by acute or chronic inflammation of target vessels, or by treatment of animals with inflammatory cytokines, such as interleukin-1. In vitro, cancer cell/endothelial cell adhesion can be enhanced by pretreating the endothelial cell monolayer with cytokines, such as interleukin-1 or tumor necrosis factor-alpha. This suggests that, in addition to organ-specific adhesion molecules, a population of inducible endothelial adhesion molecules is involved and is relevant to metastasis. 4. Further support for this model is found in the comparison to leukocyte/endothelial adhesion during leukocyte trafficking. Convincing evidence exists, both in vivo and in vitro, to demonstrate an absolute requirement for leukocyte/endothelial adhesion before leukocyte extravasation can occur. The relevance of this comparison to metastasis is reinforced by the observation that some of the adhesion molecules involved in leukocyte/endothelial adhesion are also implicated in cancer cell/endothelial adhesion. The involvement of adhesion molecules suggests a potential therapy for metastasis based on interrupting adhesive interactions that would augment other treatments for primary tumors.