Bcl-2 overexpression results in reciprocal downregulation of Bcl-X(L) and sensitizes human testicular germ cell tumours to chemotherapy-induced apoptosis.
(1/1928)
Testicular germ cell tumours are hypersentive to chemotherapy and cell lines derived from these tumours are chemosensitive in vitro. We have previously shown that these cell lines express undetectable levels of the suppressor of apoptosis Bcl-2 and relatively high levels of the apoptosis inducer Bax (Chresta et al., 1996). To determine whether the absence of Bcl-2 in these cell lines makes them highly susceptible to drug-induced apoptosis, Bcl-2 was expressed ectopically in the 833K testicular germ cell tumour cell line. Stable overexpressing clones were isolated and three clones were studied further. Surprisingly, Bcl-2 overexpressing cells were sensitized to chemotherapy-induced apoptosis compared to the parental and vector control cells. Analysis of potential mechanisms of sensitization revealed there was a reciprocal downregulation of the endogenously expressed Bcl-X(L) in the Bcl-2 overexpressing clones. Downregulation of Bcl-X(L) to the same extent using antisense oligonucleotides enhanced etoposide-induced apoptosis by twofold. Our results indicate that Bcl-2 and Bcl-X(L) have different abilities to protect against chemotherapy-induced apoptosis in testicular germ cell tumours. In contrast to findings in some tumour cell types, Bcl-2 did not act as a gatekeeper to prevent entry of p53 to the nucleus. (+info)
A novel trinuclear platinum complex overcomes cisplatin resistance in an osteosarcoma cell system.
(2/1928)
Multinuclear platinum compounds have been designed to circumvent the cellular resistance to conventional platinum-based drugs. In an attempt to examine the cellular basis of the preclinical antitumor efficacy of a novel multinuclear platinum compound (BBR 3464) in the treatment of cisplatin-resistant tumors, we have performed a comparative study of cisplatin and BBR 3464 in a human osteosarcoma cell line (U2-OS) and in an in vitro selected cisplatin-resistant subline (U2-OS/Pt). A marked increase of cytotoxic potency of BBR 3464 in comparison with cisplatin in U2-OS cells and a complete lack of cross-resistance in U2-OS/Pt cells were found. A detailed analysis of the cisplatin-resistant phenotype indicated that it was associated with reduced cisplatin accumulation, reduced interstrand cross-link (ICL) formation and DNA platination, microsatellite instability, and reduced expression of the DNA mismatch repair protein PMS2. Despite BBR 3464 charge and molecular size, in U2-OS and U2-OS/Pt cells, BBR 3464 accumulation and DNA-bound platinum were much higher than those observed for cisplatin. In contrast, the frequency of ICLs after exposure to BBR 3464 was very low. The time course of ICL formation after drug removal revealed a low persistence of these types of DNA lesions induced by BBR 3464, in contrast to an increase of DNA lesions induced by cisplatin, suggesting that components of the DNA repair pathway handle the two types of DNA lesions differently. The cellular response of HCT116 mismatch repair-deficient cells was consistent with a lack of influence of mismatch repair status on BBR 3464 cytotoxicity. Because BBR 3464 produces high levels of lesions different from ICLs, likely including intra-strand cross-links and monoadducts, the ability of the triplatinum complex to overcome cisplatin resistance appears to be related to a different mechanism of DNA interaction (formation of different types of drug-induced DNA lesions) as compared with conventional mononuclear complexes rather than the ability to overcome specific cellular alterations. (+info)
Phase I-II study of gemcitabine and carboplatin in stage IIIB-IV non-small-cell lung cancer.
(3/1928)
PURPOSE: Platinum-based chemotherapy currently represents standard treatment for advanced non-small-cell lung cancer. Gemcitabine is one of the most interesting agents currently in use in advanced non-small-cell lung cancer, and high response rates have been reported when it is administered in combination with cisplatin. The aim of the present study was to evaluate the combination of gemcitabine and carboplatin in a phase I-II study. PATIENTS AND METHODS: Chemotherapy-naive patients with stage IIIB-IV non-small-cell lung cancer received carboplatin at area under the concentration-time curve (AUC) 5 mg/mL/min and gemcitabine at an initial dose of 800 mg/m2, subsequently escalated by 100 mg/m2 per step. Gemcitabine was administered on days 1 and 8 and carboplatin on day 8 of the 28-day cycle. Dose escalation proceeded up to dose-limiting toxicity (DLT), which was defined as grade 4 neutropenia or thrombocytopenia or grade 3 nonhematologic toxicity. RESULTS: Neutropenia was DLT, inasmuch as it occurred in three of five patients receiving gemcitabine 1,200 mg/m2. Nonhematologic toxicities were mild. Gemcitabine 1,100 mg/m2 plus carboplatin AUC 5 was recommended for phase II studies. An objective response was observed in 13 (50%) of 26 patients, including four complete responses (15%) and nine partial responses (35%). Median duration of response was 13 months (range, 3 to 23 months). Median overall survival was 16 months (range, 3 to 26 months). CONCLUSION: The combination of gemcitabine and carboplatin is well tolerated and active. Neutropenia was DLT. The observed activity matches that observable in cisplatin-gemcitabine studies, whereas duration of response and survival are even higher. A phase II trial is under way. (+info)
Paclitaxel and carboplatin in the treatment of small-cell lung cancer patients resistant to cyclophosphamide, doxorubicin, and etoposide: a non-cross-resistant schedule.
(4/1928)
PURPOSE: To evaluate the efficacy of paclitaxel and carboplatin (PC) in small-cell lung cancer (SCLC) patients resistant to cyclophosphamide, doxorubicin, and etoposide (CDE). PATIENTS AND METHODS: We performed a phase II study with PC in SCLC patients who relapsed within 3 months after first-line treatment with CDE. Paclitaxel administration (175 mg/m2 by a 3-hour intravenous infusion) was followed by a 30-minute infusion of carboplatin (area under the curve 7; Chatelut formula) once every 3 weeks for five cycles. Dexamethasone, clemastine, and ranitidine were standard premedication before every cycle. RESULTS: Included were 35 patients (median age, 59 years; 16 with limited disease and 19 with extensive disease; Eastern Cooperative Oncology Group performance status of < or = 1; median time off treatment 6 weeks) who were previously treated with CDE (n = 33), oral etoposide (n = 2), and reinduction CDE (n = 15); only one patient had received three CDE treatments of five cycles. The CDE regimen was followed by local thoracic radiotherapy in seven patients. Hematologic toxicity of grade 3 or 4, for leukopenia was 27% and 6%, for thrombocytopenia 21% and 13%, and for anemia 17% and 0%, respectively, for a total of 132 cycles. Two patients had neutropenic fever; no toxic death occurred. Nonhematologic toxicity was paresthesia CTC grade 3, diarrhea grade 4, and myalgia grade 3 in one patient each. Reversible paresthesia (CTC grade 1 and 2) in toes and fingers was reported in 69% of patients. Thirty-four patients were assessable for response: complete response in two patients, partial response in 23 patients, stable disease in eight patients, and progressive disease in one patient (response rate, 73.5%; 95% confidence interval, 59% to 88%). One patient was found to have atypical carcinoid at pathologic review and was excluded. Median time to progression was 21 weeks (range, 3 to 40 weeks). Median survival was 31 weeks (range, 6 to 112 weeks). One-year survival was 9%. CONCLUSION: Second-line PC in CDE-resistant SCLC patients yields a high response rate and seems non-cross-resistant to CDE. Toxicity was mild in these poor-prognosis patients. (+info)
Phase I trial, including pharmacokinetic and pharmacodynamic correlations, of combination paclitaxel and carboplatin in patients with metastatic non-small-cell lung cancer.
(5/1928)
PURPOSE: To determine the maximum-tolerated dose of paclitaxel with carboplatin with and without filgrastim support in patients with metastatic non-small-cell lung cancer (NSCLC) and to investigate the pharmacokinetics of paclitaxel and carboplatin and correlate these with the pharmacodynamic effects. PATIENTS AND METHODS: Thirty-six chemotherapy-naive patients with metastatic NSCLC were entered into this phase I dose-escalation and pharmacokinetic study. Paclitaxel was initially administered as a 24-hour infusion at a fixed dose of 135 mg/m2, and the carboplatin dose was escalated in cohorts of three patients, using Calvert's formula [dose(mg) = area under the concentration time curve (glomerular filtration rate + 25)], to target areas under the concentration time curve (AUCs) of 5, 7, 9, and 11 mg/mL x minute. A measured 24-hour urinary creatinine clearance was substituted for the glomerular filtration rate. Once the maximum-tolerated AUC (MTAUC) of carboplatin was reached, the paclitaxel dose was escalated to 175, 200, and 225 mg/m2. When the paclitaxel dose escalation began, the AUC of carboplatin was reduced to one level below the MTAUC. RESULTS: Myelosuppression was the major dose-limiting toxicity. Thrombocytopenia was observed at a carboplatin AUC of 11 mg/mL x minute after course 2 and thereafter. End-of-infusion plasma paclitaxel concentrations and median duration of time above 0.05 microM were similar in course 1 versus course 2 at the 135 and 175 mg/m2 dose levels. The neutropenia experienced by patients was consistent with that observed in patients who had received paclitaxel alone. Measured carboplatin AUCs were approximately 12% (20% v 3% with course 1 v course 2, respectively) below the desired target, with a standard deviation of 34% at all dose levels. A sigmoid-maximum effect model describing the relationship between relative thrombocytopenia and measured free platinum exposure indicated that patients who received the combination of carboplatin with paclitaxel experienced less severe thrombocytopenia than would be expected from carboplatin alone. Of the 36 patients entered onto the study, one experienced a complete response and 17 had partial responses, for an overall response rate of 50%. The recommended doses of paclitaxel (24-hour infusion) and carboplatin for future phase II studies of this combination are (1) paclitaxel 135 mg/m2 with a carboplatin dose targeted to achieve an AUC of 7 mg/mL x minute without filgrastim support; (2) paclitaxel 135 mg/m2 with a carboplatin dose targeted to achieve an AUC of 9 mg/mL x minute with filgrastim support; and (3) paclitaxel 225 mg/m2 with a carboplatin dose targeted to achieve an AUC of 7 mg/mL x minute with filgrastim support. CONCLUSION: The regimen of paclitaxel and carboplatin is well-tolerated and has promising activity in the treatment of NSCLC. There is no pharmacokinetic interaction between paclitaxel and carboplatin, but there is a pharmacodynamic, platelet-sparing effect on this dose-limiting toxicity of carboplatin. (+info)
Phase II trial of a paclitaxel and carboplatin combination in Asian patients with metastatic nasopharyngeal carcinoma.
(6/1928)
PURPOSE: An earlier phase II trial of paclitaxel in patients with metastatic nasopharyngeal carcinoma (NPC) demonstrated a response rate of 22%. Hence we proceeded to study the combination of paclitaxel and carboplatin in these patients. PATIENTS AND METHODS: The 21-day regimen was as follows: i.v. paclitaxel 175 mg/m2 over three hours preceded by standard premedications, followed by i.v. carboplatin dosed at AUC of six infused over one hour. Only chemotherapy-naive patients with histological diagnoses of undifferentiated carcinoma of the nasopharynx, systemic metastases and radiologically measurable lesions were eligible. RESULTS: Thirty-two patients were accrued to this study. Twenty patients (62%) had at least two sites of metastasis. The main grade 3-4 toxicity was neutropenia (31%). Nine patients (28%) developed neutropenic sepsis, which caused the demise of one of them. Twenty-four patients (75%) responded to treatment, with one (3%) attaining a complete response. The median time to progression of disease was seven months and the median survival was 12 months. At one year, 52% of the patients were alive. CONCLUSIONS: The combination of paclitaxel and carboplatin is an active regimen in NPC. Its convenience of administration and good tolerability make it an attractive alternative regimen to consider for patients with metastatic disease. (+info)
Combined treatment modality for intracranial germinomas: results of a multicentre SFOP experience. Societe Francaise d'Oncologie Pediatrique.
(7/1928)
Conventional therapy for intracranial germinomas is craniospinal irradiation. In 1990, the Societe Francaise d'Oncologie Pediatrique initiated a study combining chemotherapy (alternating courses of etoposide-carboplatin and etoposide-ifosfamide for a recommended total of four courses) with 40 Gy local irradiation for patients with localized germinomas. Metastatic patients were allocated to receive low-dose craniospinal radiotherapy. Fifty-seven patients were enrolled between 1990 and 1996. Forty-seven had biopsy-proven germinoma. Biopsy was not performed in ten patients (four had diagnostic tumour markers and in six the neurosurgeon felt biopsy was contraindicated). Fifty-one patients had localized disease, and six leptomeningeal dissemination. Seven patients had bifocal tumour. All but one patient received at least four courses of chemotherapy. Toxicity was mainly haematological. Patients with diabetus insipidus (n = 25) commonly developed electrolyte disturbances during chemotherapy. No patient developed tumour progression during chemotherapy. Fifty patients received local radiotherapy with a median dose of 40 Gy to the initial tumour volume. Six metastatic patients, and one patient with localized disease who stopped chemotherapy due to severe toxicity, received craniospinal radiotherapy. The median follow-up for the group was 42 months. Four patients relapsed 9, 10, 38 and 57 months after diagnosis. Three achieved second complete remission following salvage treatment with chemotherapy alone or chemo-radiotherapy. The estimated 3-year survival probability is 98% (CI: 86.6-99.7%) and the estimated 3-year event-free survival is 96.4% (CI: 86.2-99.1%). This study shows that excellent survival rates can be achieved by combining chemotherapy and local radiotherapy in patients with non-metastatic intracranial germinomas. (+info)
1Alpha,25dihydroxyvitamin D3 and platinum drugs act synergistically to inhibit the growth of prostate cancer cell lines.
(8/1928)
The majority of men who die from prostate cancer (PC) have hormone-refractory disease. To date, chemotherapeutic agents have had little or no impact on the survival of such patients. To explore a new approach for the treatment of hormone-refractory PC, we examined the combination effects of cis- or carboplatin with vitamin D. 1alpha,25-Dihydroxyvitamin D3 (1alpha,25(OH)2D3) and its synthetic analogue, Ro 25-6760, have an antiproliferative effect on some prostate cancer cell lines. Consequently, the growth-inhibitory effects of the drugs were measured, both singularly and in combination with cis- or carboplatin, on PC cells. Our results show that although each of the drugs alone displayed antiproliferative activity, the growth inhibition of PC cells was further enhanced by the combination of 1alpha,25(OH)2D3 or Ro 25-6760 and either platinum agent. The greatest enhancement of inhibition occurred using smaller concentrations of the platinum compound in combination with higher concentrations of 1alpha,25(OH)2D3. Isobologram analysis revealed that 1alpha,25(OH)2D3 and platinum acted in a synergistic manner to inhibit the growth of PC cells. Our findings suggest that there is potential clinical value in combining 1alpha,25(OH)2D3 with platinum compounds for the treatment of advanced-stage human PC. (+info)