Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Laminin, a major basement membrane component, arrested the migration of MCF-7/AZ human breast adenocarcinoma cells that were not invasive in vitro. Migration of invasive MCF-7/6 cells was not affected by laminin. Both cell types expressed the 67 kD laminin receptor, at both mRNA and protein level, but did not express the alpha 6 subunit of the VLA-6 integrin-type laminin receptor. The presence of YIGSR peptides (100 micrograms/ml), reported to block the interaction between laminin and its 67 kD receptor, did not change the migratory response of MCF-7/AZ or MCF-7/6 cells when meeting laminin lanes. In addition, the migration of these cell types was not affected by the presence of 17-beta-estradiol (10(-6) M) or all-trans retinoic acid (10(-6) M), which were both reported to increase the number of 67 kD receptors. We could therefore not assign an involvement of the 67 kD receptors in migration of MCF-7 cells on laminin, nor did we find evidence that conditioned medium of MCF-7/6 cells contains factors that are able to initiate migration of MCF-7/AZ cells on laminin.
Clin Exp Metastasis
PMID:Arrest of MCF-7 cell migration by laminin in vitro: possible mechanisms. 183 8

The effects of 2-hydroxyethyl retinamide, N-(4-hydroxy-phenyl) all-trans-retinamide, and 13-cis-retinoic acid on the growth and metastasis of a malignant hamster melanoma cell line HM1-F5 was determined in a double blind study using 4- to 5-week-old male NIH Swiss and BALB/c derived athymic nu/nu mice. Mice were fed retinoids (0.75 and 1.0 or 1.5 mmol/kg diet) or a placebo diet ad libitum beginning on the day of s.c. inoculation of 5 x 10(5) HM1-5 cells. Tumor incidence, latency, and growth rate were similar in both strains of mice. All placebo-treated mice had lung metastasis on the day of autopsy, although the total number of metastases was lower in NIH Swiss derived athymic mice. While mean tumor incidence and latency were not significantly altered by any retinoid treatment, tumor growth rate (volume) and final tumor weight were inhibited (P less than 0.05) by 0.75 mmol/kg 13-cis retinoic acid and 1.5 mmol/kg N-(4-hydroxyphenyl) all-trans-retinamide. In contrast, at 1.0 or 1.5 mmol/kg diet, 2-hydroxyethyl retinamide had no significant effect on tumor growth rate. 13-cis retinoic acid, 0.75 mmol/kg, 2-hydroxyethyl, 1.0 mmol/kg, and N-(4-hydroxyphenyl), 1.0 mmol/kg significantly reduced the mean number of metastatic lesions in NIH Swiss derived mice, but N-(4-hydroxyphenyl) all-trans-retinamide also reduced metastatic incidence while 2-hydroxyethyl retinamide and 13-cis retinoic acid had no effect. A concentration of 1.5 mmol/kg diet of 2-hydroxyethyl and N-(4-hydroxyphenyl) all-trans-retinamide significantly reduced the overall number of gross lung metastases in BALB/c and Swiss mice, and mean number of metastases in Swiss mice. Analysis of correlation indicated that the inhibitory effect of high-dose N-(4-hydroxyphenyl) and 2-hydroxyethyl retinamide on metastasis was not associated with (independent of) any inhibitory effect on primary tumor invasiveness or growth rate. Our observations suggest that agents such as retinoids have an antimetastatic potential.
 ...
PMID:Influence of retinoids on growth and metastasis of hamster melanoma in athymic mice. 334 19

The retinoids have been investigated extensively as chemopreventive and therapeutic agents in a variety of neoplasms. They have been shown to inhibit the proliferation of transformed cell lines in vitro and transplanted tumors in vivo. In cultured murine melanoma cells, retinoids inhibit proliferation and induce differentiation. Human melanoma cell lines have shown a mixed response. The clinical experience with retinoids in melanoma has been limited. Previously we investigated the activity of topical B-all-trans-retinoic acid (Retin-A, vitamin A acid, retinoic acid, and tretinoin) against intracutaneous metastases from malignant melanoma. We saw complete remission of multiple lesions in one individual and regression of several lesions in a second patient. This experience led us to conduct the present pilot trial of topical tretinoin in dysplastic nevus syndrome. The latter is a precursor of malignant melanoma. We saw regression of some of the treated lesions to benign nevi showing minimal or no dysplasia. Thus topical tretinoin appears to possess some activity against melanoma and at least one of its precursor conditions. In view of these preliminary results, more extensive trials are warranted to better define the role of tretinoin in the chemoprevention of malignant melanoma in high-risk lesions.
 ...
PMID:Role of topical tretinoin in melanoma and dysplastic nevi. 353 20

To study the regulation of the endothelial barrier, we examined the relationship between the paracellular barrier function and the expression of 7H6 antigen localized at tight junctions of endothelial cells by using transendothelial electrical resistance (TER), fluxes of albumin and dextran, transmigration of rat mammary cancer (SST-2) cells across rat lung endothelial (RLE) cells, and immunocytochemical expression of 7H6 antigen as parameters. RLE cells cultured at a confluent cell density did not express immunohistochemically demonstrable 7H6 antigen and had low paracellular barrier functions. However, treatment of the endothelial cells with 0.5 mM dibutyryl-cAMP or 10(-6) M all-trans-retinoic acid for 4 days induced 7H6 antigen preferentially at the cell border and simultaneously enhanced the barrier function twofold, in terms of TER and fluxes of albumin and dextran. Furthermore, RA-treated RLE cell monolayers with the enhanced barrier function significantly inhibited the transmigration of SST-2 cells. These results together with those of our previous study indicate that 7H6 antigen has a crucial role in the regulation of paracellular barrier function not only in epithelial cells but also in vascular endothelial cells. The present study also suggests that tight junctions of vascular endothelium in vivo function as a barrier between blood and tissues against metastatic cancer cells.
 ...
PMID:Localization of 7H6 tight junction-associated antigen along the cell border of vascular endothelial cells correlates with paracellular barrier function against ions, large molecules, and cancer cells. 859 13

Both normal and malignant prostatic epithelial cells in culture secrete urokinase-type plasminogen activator (u-PA) into the culture medium. u-PA has been shown to have a direct association with invasive and metastatic potential of many types of cancers. We propose that prostate cancer has the intrinsic ability to invade and metastasize because of its inherent ability to secrete the serine protease u-PA. We further propose that in prostate cancer, u-PA is the key enzyme which occupies a place at the apex of the proteolytic cascade and initiates the degradative process. Subsequently, collagenases are recruited after activation of procolla-genases by another serine protease plasmin formed by the activation of plasminogen by u-PA. Extracellular proteolysis involving plasmin can cause massive degradation of the extracellular matrix. We show that u-PA alone can use fibronectin as a substrate and degrade it, but u-PA alone did not degrade laminin. Serum-free conditioned medium from DU-145 human prostatic carcinoma cells has the ability to degrade both fibronectin and laminin. However, treatment of cultures with 1 microM all-trans retinoic acid (RA) for 48 h reduced the ability of serum-free conditioned medium to cause u-PA-mediated degradation of fibronectin and laminin. Thus, RA had a protective effect on these extracellular matrix glycoproteins. Treatment of cells with RA also decreased their ability to invade Matrigel in the in vitro invasion assay in a dose-dependent manner. RA at the 0.5, 1, and 10 microM level reduced invasion to 65.7%, 46.7%, and 34.3% of control, respectively. RA reduced extracellular proteolysis and thus inhibited extracellular matrix degradation and invasion. These results may also explain one mechanism by which retinoids inhibit invasion and metastasis in vitro and in vivo. These studies have important translational value in the chemoprevention of progression of prostatic intraepithelial neoplasia to invasive carcinoma.
 ...
PMID:Urokinase-mediated extracellular matrix degradation by human prostatic carcinoma cells and its inhibition by retinoic acid. 981 42

Animal models are crucial in preclinical efficacy testing of chemoprevention agents. The most feasible, realistic, and potentially effective target for prostate cancer chemoprevention is progression from prostatic intraepithelial neoplasia (PIN) to histologic cancer and from histologic to clinically manifest cancer. There are transgenic mouse models for prostate cancer and models for PIN, but these have not yet been fully developed and evaluated for chemoprevention studies. Human prostate cancer xenografts in mice and transplantable Dunning rat prostate carcinomas can be used to assess tumor growth inhibition. Several Dunning tumors metastasize, enabling detection of inhibition of metastases. Detection of inhibitory effects on de novo prostate cancer development requires induction of a high cancer incidence and similarity of induced tumors to human prostate carcinomas. Transgenic mice with oncogenes expressed in a prostate-specific fashion, combined chronic treatment of NBL rats with estradiol-17beta and testosterone, and sequential treatment of rats with carcinogens such as N-methyl-N-nitrosourea (MNU) and chronic testosterone treatment all lead to a high incidence of prostatic adenocarcinomas. PIN occurs mostly in the former two models, and metastases are frequent in some transgenic models and the MNU-testosterone rat model. The latter model has been applied to chemoprevention agent efficacy testing. In 8 control groups, the carcinoma incidence was 77% in all accessory sex glands combined, 51% for small tumors confined to dorsolateral/anterior prostate, and 25% for large tumors of uncertain origin in the prostate area. This model was predictive of the lack of antiprostate cancer efficacy of N-(4-hydroxyphenyl)all-trans-retinamide in humans. Thus, rats given MNU and chronic testosterone represent a relevant and reliable model for efficacy testing of chemoprevention agents. In conclusion, there are now adequate animal models for prostate cancer proven to be suitable for preclinical chemoprevention studies.
 ...
PMID:Use of animal models in defining efficacy of chemoprevention agents against prostate cancer. 1032 5

As clinical oncologists, our ultimate goal in treating patients with cancer is to be able to cure their disease with a combination of treatment modalities directed at the primary tumor (surgery or radiation), and potential metastases (chemotherapy). The validity of this multimodality approach to treating cancer was initially demonstrated with the successful treatment and cure of highly chemosensitive childhood cancers, such as Wilms' tumor, and these cures were only realized when adjuvant chemotherapy was included with local control measures. We attribute our treatment successes in childhood cancers to the use of cytotoxic chemotherapy, and we attribute our inability to cure many adults with more common forms of solid tumors to the ineffectiveness of chemotherapy in these diseases. Curing disease is not the goal of most pharmacological interventions in nonmalignant diseases. With the exception of antimicrobial and anticancer chemotherapy, most of the common classes of drugs are administered with the intent of controlling the disease or the symptoms caused by disease. We administer antihypertensive agents to control blood pressure, but the underlying cause of the hypertension is not cured by this therapy. If the hypertension recurs after antihypertensive therapy is stopped, we would conclude that the therapy was successful at controlling the disease. However, if a patient's tumor relapses after completing anticancer chemotherapy, the anticancer therapy would be considered to be unsuccessful. By setting lofty goals for our therapy, we increase the probability that the treatment will not meet our own and our patient's expectations. Schipper et al. [J Clin Oncol 1995;13:801-805] proposed that we abandon the "killing paradigm," which dictates that the treatment of cancer is directed toward eradication of all cancer cells, and that we adopt a "regulatory model" of cancer. This model views cancer as a maladaptive, constantly evolving process in which cancer cells differ only slightly from normal cells as a result of a few critical genetic changes that lead to dysregulation of growth. The treatment approach under this new paradigm is debulking of tumor burden with standard multimodality therapy followed by control of residual disease by "reregulation" of the remaining cancer cells. Controlling growth and spread of this residual disease would be accomplished with non-cytotoxic agents which target pathways that are responsible for the dysregulation in cancer cells. We are now on the verge of having the capacity to test this new paradigm of cancer. Advances in our understanding of the pathogenesis of many common forms of cancer at a molecular level have led to a revolution in anticancer drug development. A number of new agents that target a variety of critical molecular targets, such as the farnesyl transferase inhibitors that block ras oncogene activation, the matrix metalloproteinase inhibitors that block the enzymes involved in tissue invasion and metastasis [Editor's note: please see "New Drugs on the Horizon, page 271], and the angiogenesis inhibitors that block new vessel formation in growing tumors, are now being clinically tested. These new classes of anticancer drugs are aimed at regulating or controlling cancers rather than killing them. The potential utility of targeting the critical molecular lesion in tumor cells is illustrated by the efficacy of all-trans-retinoic acid in acute promyelocytic leukemia (APL). Although the capacity of all-trans-retinoic acid to induce complete remissions by inducing terminal differentiation of leukemic blasts was discovered empirically, the subsequent demonstration that the pathognomonic 15:17 translocation that is present in up to 90% of cases of APL results in the production of a dysfunctional retinoid receptor appears to explain the specificity and high level of activity of retinoid therapy in this disease. This is the first example of a cancer that can be treated by specifically targeting therapy to a pathogenetic molecular lesion. Retinoids are now being used in combination with standard chemotherapy for the treatment of APL, an example of the successful application of combining a molecularly targeted agent with conventional cytotoxic chemotherapy. The development and use of molecularly targeted agents for the treatment of cancer may require us to view cancer in a new light and to adjust our goals and expectations of its treatment as well as the endpoints of our clinical trials. However, pharmacologically controlling cancer may result in an equally acceptable outcome for our patients if it leads to what Schipper et al. termed a "functional cure."
 ...
PMID:The Goal of Cancer Treatment. 1038 18

Matrix metalloproteinases (MMPs) play an important role in tumor cell invasion and metastasis. These processes require the dissolution of the basement membrane and invasion of the stromal matrix (ECM), and are mediated by MMPs. Consequently, MMP inhibitors may be attractive as new anticancer agents. To examine the potential contribution of collagenase-1 (MMP-1) in invasion of stromal matrix, we used the highly invasive and metastatic breast cancer cell line MDA-MB-231 as a model system. These cells express procollagenase-1 constitutively and this expression can be repressed by all-trans retinoic acid. Invasion of these cells into a collagen type I matrix was assessed by scanning electron microscopy (SEM), and was quantitated with a computer program and confocal laser scanning microscopy (CLSM). We found that MDA-MB-231 cells freely invaded the collagen type I matrix, suggesting that these cells possess a mechanism for activating the latent collagenase-1. In contrast, down-regulation of collagenase-1 expression by all-trans retinoic acid caused these cells to become less invasive. To confirm a role for collagenase-1 in mediating collagen type I invasion, assays were carried out in the presence of FN-439, an inhibitor of collagenase-1 enzyme activity. We found that in the presence of the proteinase inhibitor, invasion of type I collagen by MDA-MB-231 cells was also reduced. These results indicate that collagenase-1 produced by the breast tumor cells may enhance stromal matrix degradation by enabling the tumor cells to modulate their own invasive behavior, and suggest that decreasing collagenase-1 levels may be effective in breast cancer therapy.
Clin Exp Metastasis 1999 May
PMID:Human breast cancer cells activate procollagenase-1 and invade type I collagen: invasion is inhibited by all-trans retinoic acid. 1043 8

Cultured cells grown as spheroids provide an in vitro model that is closer to an in vivo tumour than conventional monolayer techniques. Previous work from our laboratory has demonstrated that spheroids formed from multidrug-resistant MCF-7 cells exhibit invasive characteristics which were not present in their sensitive counterparts. The treatment of these spheroids by all-trans-retinoic acid (ATRA), a potent inducer of in vitro and in vivo differentiation, decreases their proteolytic activity and ability to invade Matrigel-coated filters. The efficiency of ATRA is enhanced by its incorporation into low-density lipoprotein (LDL) (LDL-ATRA). Indeed, invasion through a reconstituted basement membrane was reduced by 73% with 10(-6) M ATRA and 3 x 10(-8) M LDL-ATRA. Furthermore, inhibition of invasion was correlated with a decrease in several factors: (1) secreted matrix metalloproteinase-9 and enzymes degrading type IV collagen and Matrigel films, and (2) tissue plasminogen activator. The results observed were found with a concentration of LDL-ATRA 30 times lower than that of ATRA. This could be due to the protective effect of LDL and to a better targeting of cancer cells through their LDL receptors. LDL-ATRA may therefore represent a new and potent inhibitor of invasion that could be developed for clinical trials.
Invasion Metastasis
PMID:Effects of all-trans-retinoic acid incorporated into low-density lipoprotein on invasive properties of multidrug-resistant MCF-7 spheroids. 1072 68

A patient with nonseminomatous germ cell cancer, treated with standard chemotherapy, subsequently developed a pathologically confirmed metastatic undifferentiated adenocarcinoma (non-germ-cell elements) arising from residual teratoma. Disease was present in both lobes of the liver and was deemed unresectable at the time of presentation. The patient was treated on a National Cancer Institute-sponsored institutional protocol with all-trans retinoic acid. After 60 days of oral therapy at a dose of 150 mg/m2/d (50 mg/m2 three times daily), the patient was found to have complete radiologic resolution of his hepatic metastases. He subsequently underwent surgery and his complete response was pathologically confirmed.
 ...
PMID:Dramatic response of teratoma-associated non--germ-cell cancer with all-trans retinoic acid in a patient with nonseminomatous germ cell tumor. 1140 97


1 2 3 Next >>