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

We have examined the antimetastatic effects of taxol on a PC-3 human prostatic tumor variant (PC-3 ML) which metastasizes to the lumbar vertebrae in severe combined immunodeficiency-carrying (SCID) mice. Immunofluorescence labeling indicated that taxol (0.5 to 1.0 microM for 6 h) produced an abnormal bundling of microtubules in a dosage-dependent manner. Slot blotting and gelatinase assays revealed that taxol inhibited secretion of the M(r) 72,000 and M(r) 92,000 type IV collagenases plus a M(r) 57,000 gelatinase. Radioimmunoprecipitation measurements confirmed that the drug inhibited both the secretion and the synthesis of the M(r) 72,000 collagenase. Taxol also blocked total protein secretion but did not influence total protein synthesis or turnover. Boyden chamber chemotactic studies further showed that taxol (0.5 to 1.0 microM) inhibited invasion of Matrigel. More importantly, studies in SCID mice demonstrated that taxol (50 to 250 mg/m2/day) blocked the establishment, growth, and long-term survival of PC-3 ML cells.
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PMID:Taxol blocks processes essential for prostate tumor cell (PC-3 ML) invasion and metastases. 135 84

A tumor promoter phorbol 12-myristate 13-acetate (PMA) induces characteristic reversible changes in the cell shape in certain fibroblastic lines. This reaction to PMA may be regarded as a prototype of reorganizations involving formation of stable cytoplasmic processes. Two specific drugs, Taxol and Colcemid, were used to study the role of microtubules and vimentin-containing intermediate filaments (IF) in the development of PMA-induced reorganizations. A short (I h) exposure to PMA induced formation of processes in the control cells rather than in the Colcemid treated cells having depolymerized microtubules and the IF that collapsed around the nucleus. A longer (3-4 h) exposure to PMA of the colcemid-treated cells induced a partial reversal of the IF collapse; those parts of peripheral lamellae that contained IF were transformed into narrow noncontractile processes. It is suggested that the local interaction of the IF with the actin system is an essential step in the formation of processes from lamellae.
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PMID:[The role of intermediate filaments in forming cellular processes induced in fibroblasts by the tumor promoter TPA]. 135 44

Platinum-based chemotherapy has led to an improvement in complete response rates and duration of median remission, but has only given a modest improvement in overall survival in patients with advanced ovarian cancer. Chemotherapy will in the future focus upon: (1) improving the complete remission rate with new induction regimens; (2) identifying strategies capable of converting partial remission into complete remission; (3) preventing or delaying recurrences in patients who do achieve a complete remission; (4) identifying mechanisms of antineoplastic drug resistance and pharmacologic techniques capable of reversing drug resistance. Among the treatment approaches being utilized are high-dose chemotherapy with autologous bone marrow transplantation, development of new chemotherapeutic regimens which include Taxol and hexamethylmelamine, and intraperitoneal chemotherapy. In addition, our understanding of the mechanisms of antineoplastic drug resistance has led to the development of novel therapeutic approaches. It has been demonstrated that resistance to platinum and alkylating agents is associated with both increased concentrations of cellular glutathione (GSH) as well as an increased capacity of tumor cells to repair damage to DNA. Inhibition of GSH biosynthesis with buthionine sulfoximine (BSO), a synthetic inhibitor of the enzyme gamma glutamyl cysteine synthetase, has led to the potentiation of alkylating agent activity in vitro and in vivo. A phase I trial of BSO plus melphalan is currently in progress and a trial of BSO plus carboplatin is planned. Inhibition of the DNA repair process with aphidicolin potentiates the cytotoxicity of cisplatin in drug-resistant tumor cells. Clinical trials of aphidicolin plus cisplatin await the completion of ongoing phase I trials of aphidicolin.
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PMID:Role of chemotherapy in the future treatment of ovarian cancer. 135 5

Progress in the treatment of breast cancer developed along multiple directions of research during the last decade. The concept of dose-intensity was addressed through retrospective analyses and prospective randomized trials. It was confirmed that dose-intensity correlates with higher response rates, but the effect of dose-intensive treatments on survival still needs to be established. Several new cytotoxic drugs have appeared during the last several years. Taxol, navelbine, and anthrapyrazole CI-941 have been found to have major efficacy against breast cancer, with response rates exceeding 50%. Amonafide, lonidamine, and elliptinium analogs were also shown to be effective, although to a lesser degree. Antiestrogen analogs, new aromatase inhibitors, and LHRH analogs are recent developments that are changing the face of hormonal therapy. Monoclonal antibodies are being developed and evaluated for tumor imaging applications and as vehicles for specific antitumor agents (cytotoxics, radioisotopes, and toxins). Expanding knowledge about the basic biology of breast cancer has led to the identification of growth factors and their receptors, which may be exploited for therapeutic purposes in the not too distant future.
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PMID:Overview of new treatments for breast cancer. 135 16

Taxol has been demonstrated in numerous laboratories worldwide to have broad-spectrum antitumor activity against many tumor models. The susceptible tumors include murine leukemias and solid tumors, and human solid tumor xenografts. The initial findings of taxol's ineffectiveness against most distal site tumor models was probably a consequence of the insolubility of taxol in nearly all the vehicles used in those early studies. On the occasions when an ethanol-based vehicle was used to dissolve taxol, substantial distal site antitumor activity was observed. Although no definitive schedule dependency data have evolved, once-a-day or every-other-day i.v. injections for several treatments have proved to be reproducibly effective in stringent s.c. tumor models. Attempts to discern a therapeutically synergistic cytotoxic drug combination was made on two occasions without success. In the manner evaluated, taxol plus either adriamycin, cisplatin, cyclophosphamide or etoposide (VP-16) were not meaningfully more efficacious than the more effective drug in each of those combination settings.
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PMID:Taxol: a review of its preclinical in vivo antitumor activity. 135 64

Based on results of a phase I study demonstrating antitumor activity of taxol in patients with melanoma, 34 patients with documented metastatic melanoma received taxol, 250 mg/m2, as a 24-hours infusion, repeated every 21 days, in this phase II study. All patients received premedication with dexamethasone, diphenhydramine and cimetidine. Four patients experienced anaphylactic reactions and stopped treatment. Other significant toxicity of this drug included short-lived but severe neutropenia (less than 1,000/mm2) and peripheral neurotoxicity. Four of 28 evaluable patients demonstrated objective response (14%) (confidence interval, 4%-33%) including 3 complete responses and 1 partial response. Two complete responders are continuing at 25+ and 38+ months after achieving CR. Minor evidence of anti-tumor activity was noted in five additional patients. Taxol has significant activity in melanoma and should be further studied in combination with other agents in this disease.
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PMID:A phase II study of taxol in patients with malignant melanoma. 167 65

Despite major advances in the management of ovarian cancer over the last two decades, overall prognosis remains poor. Attempts to improve early detection by screening with sonography and tumor markers have thus far been unsuccessful. The tumor marker CA-125 has, however, proven to be useful in indicating responsiveness to chemotherapy, and in turn predicts survival. Patients with well- or moderately well-differentiated stage IA-1 and IB-1 ovarian cancers have excellent survivals and do not require adjuvant therapy. In contrast, patients with poorly differentiated stage I and II tumors have a 20% failure rate and should be treated. Carboplatinum, with its favorable spectrum of toxicities, is becoming the platinum analogue of choice. Taxol is a new active agent for ovarian cancer and may prove efficacious in combination with platinum for ovarian cancer. Second-look surgery should no longer be performed routinely. Recent data suggest that tumor heterogeneity may compromise immunotherapy that targets cell surface antigens.
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PMID:Ovarian malignancy. 187 99

The tumor promoter phorbol 12-myristate 13-acetate (PMA) induces characteristic reversible changes of cell shape in certain fibroblastic lines: motile lamellas are transformed into noncontractile narrow processes; simultaneously, the actin microfilament network of lamellas is locally disorganized. This reaction to PMA may be regarded as a prototype of reorganizations involving formation of stable cytoplasmic processes. Specific drugs, Taxol and Colcemid, were used to study the role of microtubules and vimentin-containing intermediate filaments (IF) in the development of PMA-induced reorganizations. PMA readily induced formation of noncontractile processes in Taxol-treated fibroblasts; these cells had a profoundly altered microtubular system but noncollapsed IF. A short (1 hr) exposure to PMA induced formation of processes in control cells but not in the Colcemid-treated cells, which had depolymerized microtubules and IF that collapsed around the nucleus. Longer (3-4 hr) exposure of the Colcemid-treated cells to PMA induced partial reversal of the IF collapse; those parts of the peripheral lamellas that contained IF were transformed into narrow noncontractile processes. It is suggested that the local interaction of IF with the actin system is an essential step in the formation of processes from lamellas. The microtubular system controls distribution of IF in the cytoplasm and thus plays an indirect role in the reorganization of the actin cortex.
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PMID:Cytoskeletal reorganizations responsible for the phorbol ester-induced formation of cytoplasmic processes: possible involvement of intermediate filaments. 196 40

Taxol is an investigational new drug which is currently undergoing Phase II evaluation in various tumors. It is a plant alkaloid extracted from the western Yew, Taxus brevifolia. In this study, patients with metastatic melanoma who were previously untreated, received Taxol at a starting dose of 250 mg/m2 delivered as a continuous intravenous (IV) infusion over 24 hours, at 3-week intervals. All patients were premedicated with oral dexamethasone and IV diphenhydramine hydrochloride as prophylaxis against allergic reactions. Three of 25 patients had a partial response (PR) for a response rate of 12% (CI, 3%-31%). In addition four patients had objective regression of tumor that failed to qualify for a PR but these responses were as durable, lasting 6 to 17 months. No patient experienced acute allergic reactions. The major toxicity of Taxol was neutropenia requiring dose reduction to 200 mg/m2 in a majority of the patients. Our data confirm that Taxol has definite although limited activity against metastatic melanoma.
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PMID:A phase II trial of taxol in metastatic melanoma. 197 Sep 48

Microtubules are among the most strategic subcellular targets of anticancer chemotherapeutics. Despite this fact, new antimicrotubule agents that possess unique mechanisms of cytotoxic action and have broader antineoplastic spectra than the vinca alkaloids have not been introduced over the last several decades--until the recent development of taxol. Unlike classical antimicrotubule agents like colchicine and the vinca alkaloids, which induce depolymerization of microtubules, taxol induces tubulin polymerization and forms extremely stable and nonfunctional microtubules. Taxol has demonstrated broad activity in preclinical screening studies, and antineoplastic activity has been observed in several classically refractory tumors. These tumors include cisplatin-resistant ovarian carcinoma in phase II trials and malignant melanoma and non-small cell lung carcinoma in phase I studies. Taxol's structural complexity has hampered the development of feasible processes for synthesis, and its extreme scarcity has limited the use of a conventional, broad-scale screening approach for evaluation of clinical antitumor activity. However, taxol's unique mechanism of action, its spectrum of preclinical antitumor activity, and tumor responses in early clinical trials have generated renewed interest in pursuing its development.
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PMID:Taxol: a novel investigational antimicrotubule agent. 197 37


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