Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0006826 (cancer)
 1,092,456 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Taxol is a chemotherapeutic drug which acts by stabilizing microtubules, preventing normal mitosis and resulting in a block of the cell cycle at G2 and M. The drug is isolated from the yew, Taxus sp. L., and is currently being evaluated in a series of Phase II and Phase III clinical trials. Taxol blocks cells in the most radiosensitive phases of the cell cycle and thus could act as a cell cycle-specific radiosensitizer. We report the results of combined taxol-radiation exposures in the human Grade III astrocytoma cell line, G18. Taxol is a potent inhibitor of G18 cell division; a concentration of 10 nM is cytostatic for a cell population observed for at least two doubling times. Cell survival curves for G18 cells showed a significant concentration-dependent interaction between taxol and radiation. Treatment of G18 cells with a fixed taxol concentration and radiation dose showed the interaction to be dependent on the duration of taxol exposure and consequently the fraction of cells in the G2 or M phase of the cell cycle. The sensitizer enhancement ratio for 10 nM taxol at 10% survival is 1.8 and, for 1 nM taxol, it is 1.2. These results suggest that appropriate combinations of taxol have a more than additive interaction in human tissue culture and may have a role in clinical protocols.
Cancer Res 1992 Jun 15
PMID:Taxol sensitizes human astrocytoma cells to radiation. 135 Jul 55

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.
Cancer Res 1992 Jul 01
PMID:Taxol blocks processes essential for prostate tumor cell (PC-3 ML) invasion and metastases. 135 84

Taxol, an agent with a unique mechanism of action, has been shown to be highly active in patients with refractory ovarian cancer and may well have significant activity in other malignancies such as breast and lung cancer. The camptothecin analogs, another unique class of agents, have demonstrated antitumor activity in phase I and II trials. Finally, the anthrapyrazoles are intercalating agents with clinical activity in breast cancer and a toxicity profile that may permit increased dose intensity using colony-stimulating factor support. While this review focuses on these three drug classes, a number of other agents with apparently unique mechanisms of antitumor activity and unusual dose-limiting toxicities are in earlier development. These include antimetabolites; inhibitors of DNA, RNA, or protein synthesis; differentiating agents; agents that inhibit tumor growth by binding to growth factors; and agents whose mechanism of action is best classified as unknown.
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PMID:New anticancer agents: taxol, camptothecin analogs, and anthrapyrazoles. 136 58

A Phase I trial of Taxol administered as a 120 h infusion once every 3 weeks was conducted in 20 patients with advanced cancer. The initial dose was 5 mg/m2/d (25 mg/m2 total dose) and patients received 10 mg/m2/d, 25 mg/m2/d, 30 mg/m2/d and 36 mg/m2/d. Forty-four courses of taxol were administered and all patients were evaluable for toxicity. Grade 4 leukopenia was the dose limiting toxicity observed in 50% of patients treated with 36 mg/m2/d. Significant mucositis was also observed at 30 and 36 mg/m2/d. All toxicity resolved within three weeks of treatment and no cumulative toxicity was observed. No neurotoxicity or cardiotoxicity was observed and no episodes of hypersensitivity reaction were noted. We conclude that 30 mg/m2/d is an appropriate dose for phase II testing of this schedule.
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PMID:Taxol administered as a 120 hour infusion. 136 68

The standard approach for epithelial ovarian cancer has been maximum cytoreductive surgery followed by combination therapy. Several prospective control studies individually failed to demonstrate improved survival advantage for the Adriamycin containing combination compare with cisplatin plus cyclophosphamide. The two drug combination of carboplatin plus cyclophosphamide will be thought to become the treatment of choice, because it is equally effective as and less toxic than a regimen of cisplatin plus cyclophosphamide. Clinical trials are also in progress with more dose-intense regimens based on considerable retrospective evidence that survival is correlated with the dose intensity of platinum compounds. Currently, high dose carboplatin plus Gm-CSF, two-drug combination of carboplatin and cisplatin and super high dose carboplatin combined with autologous bone marrow transplantation are undergoing clinical trials. Taxol and taxotere, most important cancer drugs after emergence of cisplatin compound, has been shown to have clinical activity in drug resistant ovarian cancer patients. Majority of patients even with advanced germ cell tumors of the ovary is now cured because of the development of effective platinum-based combination chemotherapy of PVB or BEP.
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PMID:[Recent advances in ovarian cancer chemotherapy]. 138 36

The death rate from epithelial ovarian cancer has only slightly decreased in the past decade. In contrast, there have been dramatic improvements in the treatment of germ cell tumors of the ovary and the majority of patients even with advanced disease is now cured because of the development of effective platinum-based combination chemotherapy. Unfortunately, most patients with ovarian cancer have the epithelial histologic type, and only one third of these patients can be cured with standard approaches. It has recently been shown that a subset of patients with early stage ovarian cancer has a greater than 90% cure rate without chemotherapy. Consequently, a major focus of current research is to develop effective screening modalities in order to diagnose epithelial tumors when they are still confined to the ovaries and pelvis. Currently, three fourths of patients are diagnosed at the time the disease has spread throughout the peritoneal cavity, and the standard approach has been cytoreductive surgery followed by combination chemotherapy. The two-drug combination of carboplatin plus cyclophosphamide has now become the treatment of choice, although it is equally effective as and less toxic than a regimen of cisplatin plus cyclophosphamide. In addition, Taxol has been identified as an extremely active agent against this disease, and new Taxol-containing combinations are under clinical investigation. Clinical trials are also in progress with hexamethylmelamine and ifosfamide combinations as well as with more dose-intense regimens based on considerable retrospective evidence that survival is correlated with the dose intensity of platinum compounds. New agents such as WR2721, IL-3, and IL-1 alpha are undergoing clinical evaluation to determine whether the toxicities of platinum compounds can be decreased and lead to further exploitation of the dose response relationship. After induction chemotherapy, approximately 50% of patients will be in a clinical complete remission. Unfortunately, 30% to 50% of these patients will have recurrent disease; clinical trials are currently in progress to determine whether any form of therapy following the initial induction regimen can prevent or delay recurrences. Based on laboratory investigations in relevant models of human ovarian cancer, clinical trials are also in progress with novel new agents that may be capable of reversing drug resistance to platinum compounds and alkylating agents. For patients with germ cell tumors of the ovary, platinum-based combination chemotherapy has produced the same dramatic effects as in testicular cancer. Clinical trials are now focused on retaining therapeutic efficacy but decreasing the toxicity of treatment in these tumors that frequently affect women in their reproductive ages.
Curr Probl Cancer
PMID:Ovarian cancer, Part II: Treatment. 161 96

Taxol, a potent inhibitor of cell replication, enhances the assembly of tubulin into stable microtubules and promotes the formation of microtubule bundles in cells. In addition to its unique mechanism of action, taxol exhibits unusual promise as an antitumor agent, but its application in cancer chemotherapy is hampered by its limited availability. In order to better define the structure-activity profile of taxol for the design of more accessible drugs and to provide insight into the chemical features of the taxol-microtubule interaction, taxol analogues 3-8, with deleted A-ring side chain substituents and both R and S C-2' configurations, were synthesized from baccatin III through esterification at the hindered 13-hydroxyl. Employing an improved hydroxyl protection strategy, lactate analogues 3 and 4 were prepared with reasonable efficiency owing to their simple side-chain structures, while N-benzoylisoserine analogues 7 and 8 were synthesized through esterification reactions whose rates were enhanced greatly by the participation of the amide functionality. Although less biologically active than taxol, analogues 5-7 were found to promote the polymerization of tubulin and to be cytotoxic; 5 and 6 were considerably more effective than 7, whereas 3, 4, and 8 were least active. Interestingly, tubulin polymerization was sensitive to the C-2' configuration only when the amide substituent was present in the side chain. This observation suggests that the 3'-amide substituent plays an important role in preorganizing the taxol side chain to bind to microtubules.
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PMID:Biologically active taxol analogues with deleted A-ring side chain substituents and variable C-2' configurations. 167 57

Based on results of previous Phase I studies, 18 patients with documented metastatic renal cell carcinoma received Taxol 250 mg/m2 as a 24-h infusion, repeated every 21 days in this Phase II study. All patients received premedication with dexamethasone, diphenhydramine, and cimetidine. There were no responses in the 18 patients treated.
Cancer Invest 1991
PMID:Phase II trial of taxol in patients with metastatic renal cell carcinoma. 167 27

Taxol, an antimicrotubule agent, has shown promise for efficacy in treatment of breast cancer, but severe hypersensitivity reactions led to cessation of many phase I clinical trials. Consequently, investigators and the National Cancer Institute recommended that phase I and II studies of this agent use 24-hour infusions and antiallergic medications. Using a premedication regimen effective in preventing hypersensitivity reactions, we have performed a phase II trial of taxol in patients with metastatic breast cancer. Taxol was administered to 25 patients at a dose of 250 mg/m2 by 24-hour infusion every 21 days. These patients had received only one prior chemotherapy regimen, either adjuvant to surgery or for metastatic disease; all but two had received doxorubicin. In 60% of the patients, the dominant site of disease was the viscera. All patients were assessable. In April 1991, at a median time on study of 9 months (range, 5-13+ months), the objective response rate was 56% (12% complete and 44% partial; 95% confidence interval, 35%-76%). Disease progressed in only 8% of the patients. The median number of courses of therapy was 11. Granulocytopenia was the dose-limiting toxic effect, but neutropenia with fever occurred in only 5% of 232 courses. A chronic glove-and-stocking neuropathy developed in most patients, but no allergic reactions occurred. We conclude that taxol is an active agent in the treatment of metastatic breast cancer and that it warrants continued study. Currently, we are conducting a phase I trial of taxol plus doxorubicin. Future trials should address the optimal effective dose, the optimal sequencing of combinations, mechanisms of drug resistance in tumors, and dose-limiting toxic effects (particularly cardiac toxic effects of taxol given as a single agent or in drug combinations).
J Natl Cancer Inst 1991 Dec 18
PMID:Phase II trial of taxol, an active drug in the treatment of metastatic breast cancer. 168 8

Taxol is a new anti-cancer drug that is a natural product derived from the bark of the Pacific Yew tree. The drug promotes polymerization and stabilization of tubulin to microtubules and interferes with the mitotic spindle. Clinical trials indicate that taxol is effective in the treatment of patients with refractory ovarian cancer, breast cancer, malignant melanoma and probably other solid tumors. Toxicities include anaphylactoid reactions, leukopenia, peripheral neuropathy and oropharyngeal mucositis. Increased supplies of the drug are required to support further phase II and III testing.
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PMID:Taxol: a new and effective anti-cancer drug. 168 6


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