Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D01061 (CPT-11)
 1,899 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite innovations in imaging, surgery, and radiation therapy, local failure remains the principle clinical problem in most CNS malignancies. To date, chemotherapy has not major impact in the treatment of most adult CNS tumors. The inroads made by chemotherapy in pediatric CNS malignancies suggest that novel drugs, or drug combinations, may improve therapy. Topoisomerase I (Topo I) inhibitors are a relatively new group of chemotherapy drugs with a novel mechanism of action. Drugs in this group currently undergoing clinical trials are the Camptothecin analogues Topotecan, CPT-11, and 9-aminocamptothecin. There is substantial preclinical and some clinical evidence to suggest that these drugs could be useful in the treatment of CNS malignancies. Preclinical studies with the water soluble Topo I inhibitor, Topotecan, demonstrate antineoplastic activity in a variety of CNS malignancies. In addition, Topotecan has good CNS penetration in primates, and recent preliminary phase I and II clinical trials of Topotecan in pediatric and adult CNS malignancies have been promising. In this paper, we describe the unique mechanism of action, antineoplastic activity, and radiosensitizing properties of Topo I inhibitors. We present the first report demonstrating potentiation of radiation lethality by Topotecan in a human glioma (D54) cell line. The dose enhancement ratio was 3.2 at 10% survival. Thus, there is evidence to suggest that Topo I inhibitors may be beneficial in the treatment of CNS neoplasms on the basis of their antineoplastic activity alone, as well as their radiosensitizing effects. Two clinical trials which utilize concurrent Topotecan and radiation in the treatment of pediatric and adult CNS malignancies are discussed.
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PMID:The potential of topoisomerase I inhibitors in the treatment of CNS malignancies: report of a synergistic effect between topotecan and radiation. 886 97

Five promising new drugs for gynecological cancer were reviewed. Taxans (Paclitaxel: Taxol and Docetaxel: Taxotere) diterpenoid plant products enhance the polymerization of tublin. Taxol showed significant activity for platinum refractory ovarian cancer in a phase 1 clinical trial in the United States. The combination with cisplatin (CDDP) showed superior results to CDDP plus Cyclophosphamide and has been recognized as a new standard in adjuvant chemotherapy for advanced ovarian cancer. The major toxicities are myelosuppression, alopecia, and hypersensitivity reactions (HSRs). HSRs were overcome by pretreatment with anti-histamines and over 24 hours administration. It was also reported that Taxol was administered safely by over 3 hours infusion with reduced myelotoxicity, but the incidence of HSRs may be increased. Clinical trials of intraperitoneal administration and combination with Carboplatin (CBDCA) are ongoing. Taxotere, an analog of Taxol, is also effective as Taxol with a low incidence of HSRs. Topoisomerase inhibitors (Irinotecan hydrochloride: CPT-11 and Topotecan) have promising antitumor activity for ovarian and cervical cancer. CPT-11 is a semisynthetic camptothesin analog developed in Japan. It was also effective for platinum-resistant ovarian cancer, such as mucinous and clear cell carcinoma. An adverse effect was observed in the combination of CPT-11 and CDDP. The phase 1 clinical trial showed a 40% response rate against recurrent ovarian cancer. CPT-11 50-60 mg/m2 (day 1,8,15) and CDDP 50-60 mg/m2 (day 1) are a recommended schedule. The major toxicities are neutropenia and diarrhea. Thrombocytopenia is not severe and diarrhea is also controllable. Topotecan is also a promising topoisomerase inhibitor and reported superior result to Taxol for platinum refractory ovarian cancer. A phase II trial is ongoing for ovarian and cervical cancer in Japan. Nedaplatin, a new analog of cisplatin, has similar activity especially for cervical cancer with less myelotoxicity and nephrotoxicity.
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PMID:[Promising new drugs for gynecological cancer]. 935 Feb 38

DNA-topoisomerase I is the nuclear target of new anticancer drugs, namely camptothecin and its derivatives. In order to establish the rational basis for their clinical development in paediatric oncology, the antitumour activity of irinotecan (CPT-11) and topotecan, two camptothecin water-soluble derivatives, was studied in nude mice bearing neuroblastoma xenografts. The panel was composed of 4 previously established subcutaneous xenograft lines (IGR-N835, IGR-N91, IGR-NB3, IGR-NB8) that exhibited the common biological markers of poor prognosis in children (MYCN amplification, 1p deletion, paradiploidy and/or MDR1 overexpression). Irinotecan and topotecan were administered i.v. or i.p. over 5 consecutive days in animals bearing tumours. Irinotecan (40 mg/kg/day) induced 20-100% complete regressions with tumour growth delays ranging from 20 to 46 days. Two out of 10 IGR-N91 bearing animals were tumour free more than 120 days after treatment with the top dose (50 mg/kg/day). Topotecan (2.7 mg/kg/day) induced 0-67% complete regressions with tumour growth delays ranging from 23 to 50 days. One out of 8 IGR-NB3 bearing mice was tumour free at the end of the experiment. The antitumour activity of both drugs was clearly sustained at a lower dose level. Topoisomerase I activity was assayed in 15 neuroblastomas, 3 ganglioneuroblastomas and 2 normal adrenal glands, using a DNA relaxation assay. Topoisomerase I activity ranged from 69 to 1304 arbitrary units/mg of protein, and was significantly higher in immature neuroblastomas than in ganglioneuroblastomas and adrenal glands. In conclusion, irinotecan and topotecan are active against neuroblastoma xenografts. Their target is expressed in patients' tumour samples. Clinical development of topoisomerase I inhibitors in children with neuroblastoma is warranted.
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PMID:DNA-topoisomerase I, a new target for the treatment of neuroblastoma. 951 44

Camptothecin (CPT) is a pentacyclic alkaloid isolated from wood and bark of Camptotheca acuminata. Initially it was found to be highly active in a number of mouse in vivo cancer assays. Subsequently, CPT was found to uniquely inhibit an enzyme, topoisomerase I, which is involved in DNA replication. A number of CPT analogs are in advanced clinical trial, and two, Topotecan and CPT-11, have been approved for marketing by the FDA. taxol, a taxane alkaloid, was isolated from Taxus brevifolia. Taxol is a highly cytotoxic compound active in several mouse antitumor assays. It was subsequently found to uniquely inhibit tubulin, a protein involved in mitosis. After clinical evaluation, it has become the drug of choice for treatment of ovarian cancer.
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PMID:Camptothecin and taxol: discovery to clinic. 973 71

Topoisomerase I inhibitors are a new class of anticancer agents with a mechanism of action aimed at interrupting DNA replication in cancer cells, the result of which is cell death. Most if not all Topoisomerase I inhibitors are derivatives of the plant extract camptothecin. Irinotecan (CPT-11), a semi-synthetic derivative of camptothecin, is approved in the United States for the treatment of colorectal cancer. Ongoing clinical trials with CPT-11 show a 13% to 32% response rate when it is used singly or in combination with other chemotherapeutic agents such as 5-fluorouracil. The major dose-limiting toxicities of CPT-11 are myelosuppression and a dual phase diarrhea. Topotecan is another semi-synthetic analogue of camptothecin. It is approved for use in the United States for the treatment of cisplatin refractory ovarian carcinoma. Current clinical trials suggest antitumor activity against a variety of human tumor types. There is significant interindividual variability in the plasma disposition of this drug. The main dose-limiting toxicity is myelosuppression. There are other derivatives of camptothecin, as well as new formulations of the parent plant extract, that are in various stages of clinical trials. Some of these clinical trials are aimed at increasing the therapeutic benefits of the agents when used singly or in combination with other chemotherapeutic agent(s) or treatment modalities. The dose-limiting toxicity observed in most of these clinical trials is myelosuppression.
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PMID:Topoisomerase I Inhibitors. 1038 70

We have previously described a mitoxantrone-resistant MCF7 cell line that is cross-resistant to topotecan, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (CPT-11), and 9-aminocamptothecin, but not to camptothecin. A novel mechanism that resulted in decreased topotecan accumulation in MCF7/MX cells was proposed (Yang et al. Cancer Res 55: 4004-4009, 1995). We now have developed a topotecan-resistant cancer cell line from wild-type MCF7 cells. MCF7/TPT300 cells were 68.9-fold resistant to topotecan, 68.3-fold to 10-hydroxy-7-ethylcamptothecin (SN-38), and 116-fold to mitoxantrone, but only 4.1-fold to camptothecin. Topotecan efflux was increased in MCF7/TPT300 cells compared with MCF7/WT cells, and this increase was reversed upon ATP depletion by sodium azide, suggesting an energy-dependent drug efflux mechanism. However, MCF7/TPT300 cells did not overexpress P-glycoprotein or the multidrug resistance-associated protein (MRP1). In contrast, overexpression of the breast cancer resistance protein (BCRP/MXR/ABCP) was observed in MCF7/TPT300 cells as well as DNA topoisomerase I down-regulation. Our data suggest that enhanced topotecan efflux contributes partly to topotecan resistance in MCF7/TPT300 cells, possibly mediated by BCRP/MXR/ABCP.
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PMID:BCRP/MXR/ABCP expression in topotecan-resistant human breast carcinoma cells. 1093 May 38

Topotecan and irinotecan (CPT-11) are both anticancer agents active in the inhibition of topoisomerase I, an enzyme involved in DNA replication and RNA transcription. During the last decades, an immense amount of research into this class of anticancer agents has been conducted, the positive results of which led to the clinical use of topotecan and CPT-11 in ovarian cancer and colorectal cancer, respectively. Here, we review the currently most important pharmacologic aspects of these drugs, including their mechanisms of action, metabolism, activity- and toxicity-profiles and mechanisms of resistance, to provide a global insight into their pharmacology. We also discuss the effects of combinations with other anticancer agents, which have been tested for synergistic antitumor effects. Pharmacokinetic and pharmacodynamic biomodulation, to enhance the bioavailability of the active anticancer agent or to reduce drug related toxicities have currently reached clinical application. As pharmacogenetics enters the clinical stage, this will lead to more "fine-tuning" in anticancer treatment (for instance by individualized dosing). The clarification of the mechanisms of action and resistance of topotecan and CPT-11 should enable us to understand their pharmacological behavior even better and might lead to the development of more potent camptothecin-derivatives in the future.
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PMID:Pharmacology of topoisomerase I inhibitors irinotecan (CPT-11) and topotecan. 1218 13

Several agents have been evaluated for the second-line treatment of patients with non-small cell lung cancer. The TAX 317 trial found that patients treated with docetaxel (Taxotere) 75 mg/m2 had significantly longer survival than those treated with best supportive care alone. In addition, symptom control was better for patients who received chemotherapy. The TAX 320 trial found that treatment with docetaxel 75 or 100 mg/m2 resulted in significantly higher response rates than treatment with vinorelbine (Navelbine) or ifosfamide (Mitoxana), and the 1-year survival rate was also significantly better for patients treated with docetaxel 75 mg/m2. A large randomized trial compared pemetrexed (LY-231514 or Alimta) 500 mg/m2 with docetaxel 75 mg/m2. Response and survival rates were similar in the two treatment arms, however, the toxicity profile of pemetrexed was superior to that of docetaxel with significantly less Grade 3/4 neutropenia and febrile neutropenia. Fewer patients in the pemetrexed arm required hospitalization. Topotecan (Hycamtin) 2.3 mg/m2/day orally for 5 days has been compared with docetaxel 75 mg/m2 in a large 800-patient study. The results of this trial are awaited. Gemcitabine (Gemzar) and irinotecan (Campto) have been evaluated both as single agents and in combination with each other and study results do not suggest that either of these drugs is superior to docetaxel or pemetrexed. The vinca alkaloid vinorelbine has proved to be inferior to docetaxel in a randomized trial. The epidermal growth factor receptor inhibitors gefitinib (ZD1839, Iressa) and erlotinib (CP-358774, OSI 774, Tarceva) have been evaluated in Phase II trials in the second- and third-line setting. Both drugs have demonstrated interesting response rates ranging from 10 to almost 20%. The results of placebo-controlled randomized trials of this family of drugs are awaited. In summary, several studies have now found a definite role for the second-line treatment of patients with non-small cell lung cancer.
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PMID:Second-line chemotherapy for non-small cell lung cancer. 1293 56

A new, simple, sensitive and specific reversed-phase high performance liquid chromatographic (HPLC) method using ultraviolet detection was developed and validated for the analysis of CPT-11 (lambda(max)=254 nm, 365 nm) and its major active metabolite, SN-38 (lambda(max)=380 nm) in rat plasma and bile. The sample pre-treatment from plasma involved a single protein precipitation step with cold acetonitrile. In case of bile, liquid-liquid extraction with dichloromethane: tert-butyl methyl ether (3:7) was carried out. Topotecan, a structurally related camptothecin, was used as an internal standard. An aliquot of 50 microL was injected onto a C-18 column. The chromatographic separation was achieved by gradient elution consisting of acetonitrile and water (pH 3.0 adjusted with 20% o-phosphoric acid) at a flow rate of 1.0 ml/min. Total run time for each sample was 30 min. All the analytes viz. topotecan, CPT-11, SN-38 were well separated with retention times of 11.4, 13.4 and 15.5 min, respectively. Method was found to be selective, linear (R(2) approximately 0.999), accurate (recovery+/-15%) and precise (<5% C.V.) in the selected concentration ranges for both the analytes. The quantification limit for CPT-11 was 40 ngml(-1) and for SN-38 was 25 ngml(-1). The percent extraction efficiency was approximately 97% for CPT-11 and SN-38 from plasma while extraction recovery of CPT-11 and SN-38 from bile was approximately 70% and approximately 60%, respectively. The method was successfully used to determine plasma and biliary excretion time profiles of CPT-11 and SN-38, following oral and intravenous CPT-11 administration in rats. In the present study, irinotecan showed an absolute bioavailability of 30% as calculated from the pharmacokinetic data.
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PMID:Development and validation of reversed phase liquid chromatographic method utilizing ultraviolet detection for quantification of irinotecan (CPT-11) and its active metabolite, SN-38, in rat plasma and bile samples: application to pharmacokinetic studies. 1876 Nov 48

At present, chemotherapy is still to be the preferred and most significant therapeutic strategy for cancer patients in clinical practice. Although Camptothecin (CPT) has been discovered for over half century, a series of CPT derivatives such as Topotecan (TPT) and irinotecan (CPT-11) have been approved and are still to be the first-line medicines for clinical application. Up to now, the topoisomerase 1 inhibitor continues to be a significant drug development research field. Based on previous study of the structure-activity relationship, we consider that the introduction of lipophilic group at C7 position can prolong the retention time and the hydroxyl esterification at C20 can eliminate the hydrogen bond interaction, stabilize the E-lactone form and promote the anti-cancer effect. In this study, we carried out an optimization at C7 and C20 positions to afford two CPT derivatives 3g and 3j. Firstly, we predicted the possibly binding sites of two compounds with topoisomerase 1 by molecular docking. Then we evaluated the anti-proliferation effect of the two novel derivatives and compared the IC50 with CPT-11. Furthermore, the induction of cell cycle arrest and apoptosis was explored through karyomorphology, flow cytometry (FCM) and Western blot analysis. At last, we evaluated the anti-cancer effect and detected the mechanism in colorectal cancer xenograft model. In brief, all the data showed that the novel CPT derivatives (3g and 3j) could inhibit colorectal cancer proliferation via induction of cell cycle arrest and apoptosis in vitro and in vivo. It suggested that the two agents may be a new potential therapeutic strategy in the future.
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PMID:Two novel camptothecin derivatives inhibit colorectal cancer proliferation via induction of cell cycle arrest and apoptosis in vitro and in vivo. 3011 48


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