Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of subcutaneous, prostatic, and nonprostatic intraabdominal organ microenvironments to influence local tumor growth and metastasis of PC-3 human prostate carcinoma cells in athymic mice was determined. Tumorigenesis and metastasis of PC-3 were evaluated 60 days after subcutaneous and intraprostatic (orthotopic) implantation of 5 x 10(5) PC-3 cells in 6-week-old, male athymic mice. Intraprostatic implantation of PC-3 cells resulted in paraaortic lymph node metastases in 10 of 10 (100%) mice with prostatic tumors, whereas metastases were present in only 2 of 9 (22%) mice after subcutaneous implantation. Next, we determined whether the urinary bladder (nonprostatic, urogenital microenvironment) or stomach (nonurogenital, intraabdominal microenvironment) would facilitate the metastasis of PC-3 cells in athymic mice. Tumorigenesis and metastasis were 100% after subserosal implantation of PC-3 cells within the wall of the urinary bladder (n = 6 mice). Subserosal implantation of PC-3 cells into the stomach wall (n = 7 mice) also resulted in tumor formation and metastasis to regional lymph nodes in 100% of mice. In all experiments, regional lymph nodes were the most frequent site of metastasis, regardless of implantation site. We conclude that tumor microenvironment factors responsible for the metastasis of PC-3 cells in athymic mice may not be organ-specific, since nonprostatic visceral microenvironments are sufficient for predictable metastasis. Use of these models may further our understanding of how tumor microenvironment modulates expression of the metastatic phenotype by human prostate carcinoma cells.
 ...
PMID:Spontaneous metastasis of PC-3 cells in athymic mice after implantation in orthotopic or ectopic microenvironments. 775 8

There is accumulating evidence that some biochemical pathways observable by magnetic resonance spectroscopy, e.g., citrate acid and phospholipid metabolism, are altered in human prostate cancer. Four well-established human prostate cancer cell lines were therefore studied with magnetic resonance spectroscopy to compare differences in metabolic content with tumor biological behavior. Herein we demonstrate that, although each cell line has its own metabolic profile, relative creatine and citrate levels can be used to discriminate the androgen-dependent LNCaP cell line from the androgen-independent DU-145, TSU, and PC-3 cell lines.
 ...
PMID:In vitro proton magnetic resonance spectroscopy of four human prostate cancer cell lines. 775 13

Suramin is an experimental anti-neoplastic agent which has shown promising activity against prostatic carcinoma and lymphoma in clinical trials. To elucidate its mechanism of action, suramin was examined for an effect on the transport of folate compounds by tumor cells. Influx of the anti-folate methotrexate via the reduced-folate carrier system of CCRF-CEM cells was found to be highly sensitive to inhibition by suramin but not to various other arylsulfonic acids. Inhibition by suramin was competitive, and the inhibition constant Ki was 1.3 microM, a value 3-fold lower than the Kt for half-maximal influx of methotrexate. Folate binding to the membrane-associated folate-binding protein of KB cells was not affected by suramin. Growth studies revealed that the response of human CCRF-CEM, KB, PC-3 and MCF-7 cells to methotrexate was antagonized from 6- to 17-fold by pharmacological levels (10-200 microM) of suramin. Conversely, growth inhibition was additive or synergistic when suramin was combined with metoprine, a lipophilic anti-folate which enters cells by diffusion. Synergism was observed between metoprine and suramin in CCRF-CEM cells, which take up folate exclusively through the reduced-folate carrier (inhibitable by suramin), whereas additivity was observed for KB cells, which rely largely on the folate-binding protein (unaffected by suramin) for folate import. Our results indicate that inhibition of cellular transport of folate compounds may explain part of the anti-neoplastic effects of suramin on tumor cells.
 ...
PMID:Suramin sodium: pronounced effects on methotrexate transport and anti-folate activity in cultured tumor cells. 779 Jan 20

Recently, we demonstrated that an androgen-regulated cell adhesion molecule, C-CAM, acts as a tumor suppressor in prostate cancer development. In this study, we further explored the possibility of applying C-CAM as a potential agent for developing prostate cancer gene therapy using an adenoviral delivery system. We found that prostate cancer cells, in general, were sensitive to adenoviral infection. In vitro characterization indicated that C-CAM1 protein was detected only in C-CAM1 adenovirus-infected cells but not in antisense control virus-infected cells, and the levels of expression showed dose dependency. Because of the stability of the protein, C-CAM expression in viral-infected cells appeared to be a long-lasting event, indicating that C-CAM may be superior to many other known tumor suppressors that have a short protein half-life. Most importantly, the delivery of a single dose of C-CAM adenovirus was able to repress the growth of PC-3-induced tumors in nude mice for at least 3 weeks. Taken together, these data indicate that C-CAM is a potential candidate for human prostate cancer therapy.
 ...
PMID:Application of a tumor suppressor (C-CAM1)-expressing recombinant adenovirus in androgen-independent human prostate cancer therapy: a preclinical study. 779 10

We recently demonstrated that C-CAM, an epithelial-cell adhesion molecule of the immunoglobulin supergene family, could be regulated by androgen and might act as a growth repressor during differentiation of the prostatic epithelium. To define the role of C-CAM in prostatic tumorigenesis, a tumorigenic human prostatic cancer cell line, PC-3, was transfected with an expression plasmid containing C-CAM1 (a C-CAM isoform). Transfected clones showed significantly lower growth rates, reduced anchorage-independent growth, and less tumorigenicity in vivo than control cells. Furthermore, transfection of an antisense vector into a nontumorigenic prostatic epithelial cell line, NbE, resulted in tumor formation in nude mice. Sublines derived from these NbE-induced tumors had lower levels of C-CAM than did control cells. These data suggest that C-CAM1 can function as a tumor suppressor in prostate tumorigenesis.
 ...
PMID:Tumor suppressive role of an androgen-regulated epithelial cell adhesion molecule (C-CAM) in prostate carcinoma cell revealed by sense and antisense approaches. 780 32

The development of camptothecin-like compounds as inhibitors of topoisomerase I for the treatment of resistant tumors has generated clinical excitement in this new class of drugs. We have developed two novel water-soluble camptothecin analogues which are specific inhibitors of topoisomerase I and are potent cytotoxins with significant antitumor activity. We added water-solubilizing groups off position 7 in the B ring of either 10,11-ethylenedioxy- or 10,11-methylenedioxy-20(S)-camptothecin. These water-soluble camptothecin analogues were demonstrated to be nanamolar inhibitors of the topoisomerase I enzyme in the cleavable complex assay. The compounds, GI147211 [7-(4-methylpiperazinomethylene)-10,11-ethylenedioxy-20(S)-camp tot hecin], and GI149893 [7-(4-methylpiperazinomethylene)-10,11-methylenedioxy-20(S)-cam pto thecin], were compared to topotecan, a known water-soluble inhibitor of topoisomerase I. Both GI compounds were found to be slightly more potent than topotecan as inhibitors of topoisomerase I in the cleavable complex assay and were 1.5-2 times more soluble. Tumor cell cytotoxicity assays using 5 separate cell lines demonstrated that both GI compounds were 5-10 times more potent than topotecan, although by comparison all three topoisomerase I inhibitors were unaffected by the multidrug resistance P-glycoprotein. The antitumor activity of all three topoisomerase I inhibitors was compared concomitantly in two human colon xenograft models. In both models, GI147211 and GI149893 were able to induce regression of established HT-29 and SW-48 colon tumors by as much as 60%. The antitumor activity of both compounds were also demonstrated in the MX-1 and PC-3 xenografts. Microscopic examination of selected tissues indicated that drug-induced toxicity was primarily limited to the gastrointestinal tract and was comparable among the three compounds. Further clinical development of this class of compounds is ongoing.
 ...
PMID:In vivo antitumor activity of two new seven-substituted water-soluble camptothecin analogues. 783 31

The effects of estrogens and progestogens in the management of prostatic adenocarcinoma are generally believed to be related to their suppressive effect on the hypothalamic-pituitary-testicular axis, but other mechanisms have also been suggested. The present study was designed to investigate if an androgen-insensitive human prostatic cancer cell line (PC-3) is sensitive to estrogens or progestogens and to elucidate possible mechanisms of action. Both estrogens and progestogens in high doses (10(-5) M) suppressed tumor cell growth. At these high doses medroxyprogesterone acetate (MPA) most effectively reduced the uptake of 86rubidium chloride, indicating the strongest effect on ion transport and membrane permeability. Effects on rubidium transport were also seen after estrogen treatment. It is suggested that estrogens and progestogens have direct cytotoxic effects on prostatic carcinoma cells in vitro, possibly by an effect on the cell membrane.
 ...
PMID:Effects of estrogens and progestogens on the membrane permeability and growth of human prostatic carcinoma cells (PC-3) in vitro. 784 66

Human solid tumors (prostate carcinomas PC-3 and DU-145, breast carcinoma MX-1, cervical carcinoma ME-180, small cell lung carcinoma SW2, and glioblastoma T98G) were grown as xenografts in nude mice. Using the Eppendorf pO2 histograph microelectrode system, the oxygen profiles of the tumors were determined while the animals breathed air or carbogen (95% O2/5% CO2), and after administration of the perfluorochemical emulsion Oxygent-CA (8 ml/kg) under air breathing and carbogen breathing conditions. Under normal air breathing with or without Oxygent-CA administration the mean oxygen tensions were between 4.9 and 9.3 mmHg and each tumor had severely hypoxic regions where the pO2 was less than 5 mmHg. The severely hypoxic regions comprised 41-71% of the oxygen tension measurements under normal air breathing conditions. Carbogen breathing alone increased the mean oxygen tensions to 10.9-23.9 mmHg. Administration of Oxygent-CA and carbogen breathing increased the mean oxygen tensions over the levels of carbogen breathing alone to varying degrees. The highest mean oxygen tensions were 40.8 mmHg in the T98G glioblastoma and 24.5 mmHg in the ME-180 cervical carcinoma. Investigation of the use of Oxygent-CA/carbogen to increase the oxygenation of clinical tumors is warranted.
 ...
PMID:Oxygenation of human tumor xenografts in nude mice by a perfluorochemical emulsion and carbogen breathing. 784 46

Hormone refractory prostate cancer remains an incurable disease. Newer agents with more activity are required. Genistein is a flavone compound with anti-tumor activity against various tumor systems in vitro. This study is undertaken to assess the efficacy of genistein against hormone refractory prostate cancer. In vitro, genistein appears to be cytotoxic to both the rat prostate cancer cell line MAT-LyLu and the human prostate adenocarcinoma cell line, PC-3. In vivo, however, genistein failed to significantly inhibit the growth of subcutaneously implanted MAT-LyLu cells. More information regarding the pharmacokinetics and bio-availability of genistein is needed to determine if this is an active agent in human metastatic prostate cancer.
 ...
PMID:An in vitro and in vivo study of antitumor effects of genistein on hormone refractory prostate cancer. 787 90

Stromal cells from the prostate were recently shown to inhibit clonal growth of the prostatic carcinoma cell lines PC-3 (hormone-independent) and LNCaP (hormone-sensitive) in coculture. Our study revealed that stromal cell-conditioned medium strongly inhibited proliferation of PC-3 and LNCaP cells when grown in monolayer culture. Antiproliferative activity was found to be reversible, and was produced specifically by prostatic stromal cells and not by stromal cells derived from skin, foreskin, uterus, kidney, and Wilms' tumor. Inhibition was not species-specific, since the cell lines AT-2.1 and MATLyLu, derived from the Dunning rat prostate tumor, were also sensitive. No inhibition, however, occurred on breast and renal carcinoma cell lines, suggesting a prostate-specific action. The putative inhibiting factor(s) could be concentrated and partially purified by ammonium sulfate precipitation. The possible role in stromal control of epithelial cell proliferation is discussed.
 ...
PMID:Inhibition of prostatic epithelial cell proliferation by a factor secreted specifically by prostatic stromal cells. 789 50


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>