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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the reasons for the development of cancers and their relentless malignant progression--even in the face of highly toxic anticancer therapies--is an enhanced ability to bypass mechanisms responsible for precipitating cell death. The latter include active cell death mechanisms often referred to as programmed cell death or apoptosis. Active cell death is a genetically controlled, intrinsic suicide process, and evidence is rapidly accumulating that cancers are more resistant to undergoing apoptosis than normal cells. This may be a major factor explaining the ability of small numbers of tumor cells, e.g. tumor emboli, to survive transit in the bloodstream and form distant metastases in ectopic organ sites. In addition, because many therapeutic agents ultimately kill tumor cells by inducing apoptosis, acquisition of an apoptosis-resistant phenotype could be a generic mechanism of drug or radiation resistance in cancer patients. It follows that uncovering the basis of the enhanced survival capacity of tumor cells is fundamental to gaining a better understanding of tumor progression, metastasis formation, and response to therapy. In this respect many of the principles thought to regulate apoptosis in cancers have been established using conventional, two-dimensional monolayer cell cultures of 'liquid' tumors, i.e. unicellular model systems. Suppression of apoptosis in solid tumors, however, may be governed by different cellular and genetic mechanisms. Evidence is presented in support of this hypothesis, and that multicellular architecture may render individual tumor cells within solid tumors less susceptible to apoptosis. This multicellular resistance--which may represent a form of group protection--can also be induced or acquired during cytotoxic drug chemotherapy or cytokine-mediated growth inhibition of solid tumors. It follows that disruption of solid tumor multicellularity may provide a means of enhancing the therapeutic destruction of small solid tumors such as occult micrometastases. Such disruptions may be brought about by a variety of so-called antiadhesive agents.
Invasion Metastasis
PMID:Impact of multicellular resistance on the survival of solid tumors, including micrometastases. 765 32

A body of evidence that vascular-mediated damage occurs in murine tumours after many existing forms of anti-tumour therapy is rapidly accumulating (see Gray Conference Proceedings edited by Moore & West, 1991). Rapid conventional screens of cells in vitro or using leukaemias of lymphomas will not detect this mode of action and such screens will therefore miss effective agents. A change in the approach to experimental cancer therapy is needed to ensure that this important new avenue is fully investigated. Solid tumours will need to be studied and the importance of specific tumour cell biochemistry (e.g. on tissue factor procoagulant activity), of endothelial status and the immunocompetence of the host are all likely to be important. It is a subject of considerable debate at present whether transplanted subcutaneous mouse tumours are adequate models and whether they will reflect the response of spontaneous tumours, or even of transplants into other sites. Xenografts are not likely to be appropriate if the immuno-suppressed hosts lack the cells needed for the cytokine component of the pathway. The strategy of design and screening of new agents, for scheduling of existing agents and particularly the sequencing of adjunctive therapies are likely to be completely different for the "direct" tumor cell or "indirect" vascular-mediated approaches. It may eventually be appropriate to combine vascular manipulation with direct cytotoxicity aimed at malignant cells but the two mechanisms must be recognized as distinct entities and considered separately before attempting to coordinate them. It is important therefore to identify the "hallmarks" of vascular mediated injury and the means by which this can be distinguished from direct cell kill. These may be detectable in the tumour response but clues can also be gained from the side effects that are seen in normal tissues both with existing and with novel therapies (Figure 7). The appeal of vascular-mediated ischaemic therapy is that it is systemic and will have the potential of being effective on any tumour with a newly evoked vascular network, i.e. of about 1 mm in diameter, but it will be even more effective on large tumours than on small. Thus it should affect both large primary tumours and disseminated small metastases. The studies with many different anti-cancer agents have illustrated the potential complexity of responses that can appear to cause tumour cell death by collapse or occlusion of the blood supply. They have also focused attention on features of disparate agents, e.g. TNF, FAA, PDT, which may share similar pathways. No single feature of neovasculature can be highlighted as the sole route by which such antivascular therapy should be targeted. Rapid proliferation of the endothelial cells may prove to be a target, but it also influences differentiation characteristics, so that the immature cells will function abnormally. The permeability of these poorly formed vessels may lead to extravasation of proteins leading to increase interstitial pressures and by this means to an imbalance between intravascular and extravascular pressures and hence to collapse of the thin-walled vessels. Changes in systemic blood pressure, cardiac output, viscosity or coagulation and especially a redistribution of regional perfusion would all have differential effects in tumours and normal vessels. Clearly both vascular patho-physiology and the complexity of endothelial cell function and its imbalance in neovasculature will be important in understanding the mechanism of action of antivascular strategies. This very challenging boundary between oncology and a number of other medical and biological fields promises to lead to altered attitudes to existing therapies and the discovery of completely new classes of anti-cancer agents. The next decade should translate into clinical benefit for patients if the progress in this field continues to be as rapid as it has been in the late eighties. We must now determine what characteristics make one tumour more sensitive than another to agents such as heat, PDT, cytokines and FAA, and learn how to extrapolate from those rodent tumours to the human.
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PMID:Review article: angiogenesis, neovascular proliferation and vascular pathophysiology as targets for cancer therapy. 768 69

Recombinant interleukin-2 (IL-2) products (e.g. aldesleukin, teceleukin) are nonglycosylated, modified forms of the endogenous compound. IL-2 acts as a pleiotropic mediator within the immune system, having a variety of effects via specific cell surface receptors. The interaction of IL-2 with the IL-2 receptor induces proliferation and differentiation of a number of T lymphocyte subsets, and stimulates a cytokine cascade that includes various interleukins, interferons and tumour necrosis factors. Antitumour effects of IL-2 appear to be mediated by its effects on natural killer, lymphokine-activated killer (LAK) and other cytotoxic cells. In vivo and in vitro effects of IL-2 seem to be dependent to a large extent on the environment; many studies have reported conflicting results, perhaps due to diverse populations of effector cells, the availability of other cytokines that have synergistic or inhibitory influences, and the dosage regimens used. The recombinant products appear to be biologically indistinguishable from native IL-2 in vitro and in vivo; the former induce minor antibody formation but this does not appear to alter functional properties. In patients with metastatic renal cell carcinoma, IL-2 therapy achieves average objective response rates of 20% (range 0 to 40%), with a complete response rate of about 5% (range 0 to 19%). Response duration varies considerably but can be durable (lasting for > 12 months), with some patients remaining in complete response for > 60 months. It is unclear at present whether higher dosage regimens improve clinical response, or whether combination therapy with other agents and/or adoptive therapy is beneficial. Survival duration may depend on the risk factors present, with poorer performance status and more than one site of metastases associated with shorter survival times. Patients with metastatic malignant melanoma receiving IL-2 as monotherapy show an average objective response rate of 13% (range 3 to 24%); however, objective response rate averages 30% (range 4 to 59%) when IL-2 is used in combination with other agents. Overall median survival appears to be about 10 months. Preliminary data indicate that IL-2 produces a lower response rate in patients with refractory colorectal carcinoma, ovarian cancer, bladder cancer, acute myeloid leukemia or non-Hodgkin's lymphoma. Adverse effects accompanying high dose, intravenous IL-2 therapy can be severe, with cardiovascular, pulmonary, haematological, hepatic, neurological, endocrine, renal and/or dermatological complications frequently requiring doses to be withheld.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Interleukin-2. A review of its pharmacological properties and therapeutic use in patients with cancer. 769 34

Most tumors grow progressively and overwhelm the host. The rare but documented cases of spontaneous regression of primary tumors are indicative of the potential of tumor-bearing hosts to develop a significant antitumor response. Because most tumors grow progressively in the host, it is not surprising that the majority of studies have focused on T lymphocytes that infiltrate these tumors. Although these studies have generated significant and useful information during the period of tumor growth, they can only speculate on the mechanisms that are involved in tumor rejection. We have used a well developed sponge model of concomitant tumor immunity that allows us to compare the immunologic events that occur during tumor progression vs rejection. In this model, an animal harboring a primary EMT6 mammary tumor is challenged with a secondary tumor implant through a pre-implanted gelatin sponge. During the manifestation of concomitant tumor immunity, the secondary tumor is rejected and the effector cells mediating the response are retained within the sponge matrix. Using this model we analyzed the TCR usage, cytotoxic activity of lymphocytes, and cytokine production at both tumor sites. The data revealed that tumor-rejecting lymphocytes isolated from the site of secondary tumor implant were cytotoxic toward EMT6 cells, whereas tumor-infiltrating lymphocytes isolated from the progressing primary tumor were not. Interestingly, the TCR-V beta repertoire of the tumor-infiltrating lymphocytes and tumor-rejecting lymphocytes were identical with V beta 1 and V beta 8 being predominant at both sites. Furthermore, the rejection site showed higher gene expression of IFN-gamma, TNF-alpha, and IL-10 whereas TGF-beta expression was slightly higher in the progressing tumors. These findings suggest that the disparate effector functions observed during tumor progression vs rejection are not caused by different T cell phenotypes but may be due instead to influences exerted by cytokines produced at the tumor sites.
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PMID:T lymphocytes infiltrating sites of tumor rejection and progression display identical V beta usage but different cytotoxic activities. 770 35

In recent years, several studies have documented that melanoma cell lines produce various cytokine/growth factors and their receptors. Since cell lines can acquire altered properties, such as changes in growth requirements, we studied constitutive cytokine gene expression in melanoma cells from 20 fresh surgical specimens: seven primary melanomas and 13 metastases (12 lymph-node metastases and one subcutaneous metastasis). After tumour cell isolation by discontinuous gradient, we tested for mRNA expression by means of reverse-transcriptase polymerase chain reaction. Most melanoma cells tested expressed growth factors: basic fibroblast growth factor (bFGF), interleukin (IL)1 alpha, IL-1 beta, IL-6 and IL-8 and, in five cases out of 20, expressed granulocyte-macrophage colony-stimulating factor (GM-CSF) (two out of five were also positive for GM-CSF receptor). Our results do not point to a direct correlation between cytokine expression and clinical stage at the time when the bioptic specimen was obtained. However, they allow us to suggest a possible metastatic tumour cell phenotype, in which autogenous GM-CSF expression could modulate immune response against the tumour cell itself or could potentiate metastatic colonization properties.
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PMID:Cytokine expression in human primary and metastatic melanoma cells: analysis in fresh bioptic specimens. 773 55

Interleukin-10 (IL-10), originally described as a product of TH2 cell clones, has been recognized as a potential immunosuppressive cytokine. To investigate the relevance of IL-10 in melanoma patients in vivo, we studied IL-10 serum levels in 104 untreated patients in different stages of the disease; 20 healthy subjects and 22 patients with inflammatory dermatoses served as controls. Serum levels were measured by ELISA. Only one of 31 patients with stage I melanoma (3%) and one of 16 stage II patients (6%) showed detectable IL-10 levels. Interestingly, six of 17 patients with lymph node metastases (stage III, 35%) and 29 of 40 patients with widespread disease (stage IV, 73%) revealed IL-10 levels of 15-480 pg/ml. No healthy person and only one control patient had a detectable IL-10 serum level. The data suggest that IL-10 in melanoma patients may contribute to down-modulation of anti-tumour responses in vivo.
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PMID:Elevated serum levels of interleukin-10 in patients with metastatic malignant melanoma. 773 58

Melanoma is one of the first tumors in which gene therapy protocols are being tested. The promising results of in vitro and animal studies are now being translated into phase I studies in patients with metastatic disease. Attention is being paid to the safety of the various techniques for gene transfer. As yet, almost all protocols involve ex vivo delivery of genetic material because we lack techniques to ensure 100% transduction of target cells in vivo. The majority of studies in animal models and most current clinical trials involve cytokine gene-modified cells. For melanoma, a number of the target epitopes for cytotoxic lymphocytes have been discovered so that rational testing of the immunomodulatory effects of such therapy is now possible.
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PMID:Scientific aspects of gene therapy in melanoma. 775 81

Although adjuvant chemotherapy has made some progress in the treatment of colorectal cancer, chemotherapy of metastatic disease remains disappointing. Autologous bone marrow or stem cell transplantation following supralethal chemotherapy is presently not of major significance in tumors of the intestine. The registry of the EBMT (European Cooperative Group for Blood and Marrow Transplantation) contains at March 1993 a total of 2085 cases of autotransplants for solid tumors, of which only 19 were performed for disseminated gastrointestinal cancer (15 gastric, 4 colon). It remains to be shown, whether the presently poor results can be improved upon inclusion of lymphokine-activated killer cells (LAK-cells) by use of cytokine combinations or by the use of tumor infiltrating lymphocytes (TIL) post transplantation.
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PMID:[Autologous bone marrow transplantation in intestinal carcinoma]. 776 52

Therapeutic effect of a vaccinia colon oncolysate prepared with interleukin-2 (IL-2) gene-encoded vaccinia virus (IL-2VCO) in combination with recombinant interferon-alpha (IFN-alpha) was studied in a syngeneic murine CC-36 colon hepatic metastasis model. Treatment with this IL-2VCO+IFN-alpha produced a higher survival rate (90% on day 60 after tumor transplantation) in mice having CC-36 hepatic metastases when compared to treatment with IFN-alpha (0%), VCO+IFN-alpha (0%), or IL-2VCO (11%). The only treatment that produced a survival rate similar to the survival rate of IL-2VCO+IFN-alpha was VCO+IL-2 + IFN-alpha (survival rate was 67%). The cause of the prolonged survival with the IL-2VCO+IFN-alpha treatment was identified as the reduction of CC-36 hepatic metastases (mean liver weight 1.31 g and mean tumor nodules 2). This reduction was significant when compared to IL-2VCO (1.58 g and 11), VCO+IFN-alpha (1.96 g and 53), and IFN-alpha (2.24 g and 91) treatments. The mechanism of the induction of antitumor response by the VCO+IL-2+IFN-alpha treatment was analyzed by measuring the direct cytotoxic activity of IFN-alpha on CC-36 tumor cells and by measuring the induction of cytolytic T-cell activity against CC-36 tumor cells. Results suggest that IFN-alpha produced minimal direct cytotoxic activity against CC-36 cells; however, the IL-2VCO+IFN-alpha combination therapy induced an enhanced cytolytic T-cell activity against CC-36 tumor cells (85.1% at E:T 100:1) when compared to other treatments (IL-2VCO 26.3%, VCO+IFN-alpha 13.4%, and IFN-alpha alone 6.3%). In addition, the role of T-cell subsets for the induction of antitumor immune response was analyzed in a survival study that used CD8-positive T cell-depleted mice. It was found that the survival rate was affected in mice depleted with CD8-positive T cells and treated with IL-2VCO+IFN-alpha when compared to control mice which had no T-cell depletion and were treated with IL-2VCO+IFN-alpha. This study suggests that the addition of IFN-alpha along with IL-2VCO increased the survival rate of mice having CC-36 hepatic metastases through the induction of CD8-positive T cells. Furthermore, this study confirms that IL-2VV can be used as a substitute for recombinant IL-2 in cytokine-augmented active specific immunotherapy.
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PMID:Immunotherapy of a vaccinia colon oncolysate prepared with interleukin-2 gene-encoded vaccinia virus and interferon-alpha increases the survival of mice bearing syngeneic colon adenocarcinoma. 788 37

The macrophage colony-stimulating factor (CSF-1) is best known as a hematopoietic cytokine important to macrophage activation. Recently, the importance of CSF-1 and its receptor (encoded by the c-fms proto-oncogene) in epithelial ovarian cancer has also been recognized, with overexpression of CSF-1 denoting poor prognosis in ovarian cancer patients. During macrophage activation, CSF-1 promotes urokinase-type plasminogen activator (uPA) activity; in macrophages and in malignant cells of lung, breast, colon, and prostatic origin, uPA activity is strongly correlated with the ability to invade and, in the malignant cells, to metastasize. While there is clear evidence of CSF-1 and uPA expression in primary and metastatic ovarian cancer, the significance of their expression to invasion of these cells has not been explored. We find that all of our ovarian cancer cell lines which we have studied co-express CSF-1 and uPA transcripts and protein. Urokinase expression in these ovarian cancer cell lines correlates with the degree of tumorigenicity in nude mice, with the most virulent tumor resulting from Hey cells, a strong expressor of uPA. We studied the invasion of these primary and established ovarian cancer cells through a Matrigel (reconstituted basement membrane matrix) barrier. The ability of ovarian cancer cells to invade is strongly correlated with endogenous CSF-1 expression (Pearson's correlation, r = 0.91; P = 0.01). A total of 0.90 +/- 0.16% of Bix3 cells (very weak expressor of CSF-1) invaded through the barrier, in contrast to 6.95 +/- 0.75% of Hey cells (strong CSF-1 expressor) and 10.44 +/- 2.33% of Bixler cells (the strongest CSF-1 expressor). We studied the ability of two of the cell lines to invade human laminin and type IV collagen (Bix3, a weak invader of Matrigel, and Hey, a strong invader), to determine (a) whether our results on a Matrigel matrix may represent a relevant model for invasion in humans and (b) whether there is a potential confounding effect from the cytokines and proteases in Matrigel. On this human simple matrix, we confirm that Bix3 is a weakly invasive cell line (0.33 +/- 0.04% invasion) which contrasted to the strongly invasive Hey cell line (8.51 +/- 0.47%). Treatment of Bix3 cells with exogenous CSF-1 stimulates percentage of invasion by 2-fold and results in a similar increase in the level of uPA transcripts and cellular associated uPA antigen. Furthermore, cell surface-bound uPA increased from 74% in the absence of CSF-1 to 100% (fully saturated) in the presence of CSF-1.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Macrophage colony-stimulating factor mediates invasion of ovarian cancer cells through urokinase. 788 68


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