Loss of transcription factor IRF-1 affects tumor susceptibility in mice carrying the Ha-ras transgene or nullizygosity for p53.
(73/7975)
The transcription factor IRF-1 has been implicated in tumor suppression: IRF-1 suppresses cell transformation and mediates apoptosis in vitro. Here we show that the loss of IRF-1 alleles per se has no effect on spontaneous tumor development in the mouse but dramatically exacerbates previous tumor predispositions caused by the c-Ha-ras transgene or by nullizygosity for p53. Grossly altered tumor spectrum, as compared to p53-null mice, was also observed in mice lacking both IRF-1 and p53, and cells from these mice show significantly higher mutation rate. Our results suggest that IRF-1 is a new member of the tumor susceptibility genes. (+info)
Brain-derived neurotrophic factor promotes survival and chemoprotection of human neuroblastoma cells.
(74/7975)
Brain-derived neurotrophic factor (BDNF) promotes neuronal survival and protection against neuronal damage. We addressed whether BDNF might promote survival and chemoprotection in neuroblastoma (NB) using a drug-sensitive human NB cell line. All-trans-retinoic acid (ATRA) induces a striking phenotypic differentiation of NB1643 cells, and exogenous BDNF treatment promotes survival of these differentiated cells. ATRA induces TRKB expression, and exogenous BDNF stimulates both autophosphorylation of TRKB and induction of the immediate early gene, FOS, in these cells. BDNF mRNA is expressed in NB1643 cells. Because the time course of TRKB induction closely parallels phenotypic differentiation of these cells, it seems probable that ATRA induces differentiation of NB1643 cells by establishing an autocrine loop involving BDNF and TRKB. Exogenous BDNF treatment resulted in a further increase in neurite outgrowth, which again suggests that an autocrine loop is involved in differentiation of NB1643 cells in response to ATRA. We then tested whether BDNF might afford drug resistance in NB and found that BDNF does indeed protect in this NB model against cisplatin, a DNA-damaging agent actually used in the treatment of NB. (+info)
Cisplatin-induced activation of mitogen-activated protein kinases in ovarian carcinoma cells: inhibition of extracellular signal-regulated kinase activity increases sensitivity to cisplatin.
(75/7975)
Cisplatin treatment activates multiple signal transduction pathways, which can lead to several cellular responses including cell cycle arrest, DNA repair, survival, or apoptosis. We investigated the response of the mitogen-activated protein kinases, extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun-N-terminal kinase 1 (JNK1), and p38, to cisplatin treatment in the ovarian carcinoma cell line SK-OV-3. Cisplatin caused a late and prolonged induction in a dose-dependent manner of both ERK1/2 and JNK1 activity. ERK1/2 and JNK1 activities continued to increase in magnitude up to 24 h following initiation of cisplatin treatment. In contrast, cisplatin treatment had no effect on p38 activity. Transplatin failed to induce either ERK1/2 or JNK1 at 24 h, which suggests that the activation of these kinases was dependent on cisplatin-specific DNA damage. Treatment with cycloheximide resulted in inhibition of cisplatin-induced ERK1/2 activation, demonstrating that ERK1/2 activity induced by cisplatin was dependent on de novo protein synthesis. Furthermore, inhibition of cisplatin-induced ERK1/2 activity by PD 98059 caused enhanced cisplatin cytotoxicity. Similar enhanced cytotoxic effects of cisplatin were also observed following treatment with PD 98059 in the ovarian carcinoma cell line UCI 101. These observations indicate that ERK1/2 activation induced by cisplatin partially protects cells from cisplatin cytotoxicity. Continued investigation into the mechanism by which the ERK pathway and other signal transduction pathways modulate the response to cisplatin may be helpful in the development of new strategies for improving the therapeutic use of platinum drugs. (+info)
BOMP/EPI intensive alternating chemotherapy for IGCCC poor-prognosis germ-cell tumors: the Spanish Germ-Cell Cancer Group experience (GG)
(76/7975)
BACKGROUND: Patients with poor-prognosis germ-cell tumors according to the IGCCC have a poor long-term survival. This study evaluates the efficacy and toxicity of the intensive alternating chemotherapy regimen BOMP/EPI in these patients. PATIENTS AND METHODS: Patients with IGCCC poor-prognosis germ-cell tumors treated at 13 centres were studied. Treatment consisted of bleomycin 30 mg, vincristine 2 mg, methotrexate 300 mg/m2 and cisplatin 100 mg/m2 (BOMP), alternating after a 14-day interval with etoposide 120 mg/m2 day 1-4, ifosfamide 1.3 g/m2 day 1-4 and cisplatin 25 mg/m2 day 1-4 (EPI). BOMP was administered 21 days after the EPI. Bleomycin was administered weekly per 12 weeks. RESULTS: Thirty-eight patients were treated. The median number of cycles administered was 7 (1-10 cycles). Eighteen patients achieved complete responses with chemotherapy alone (12 had necrosis and 2 mature teratoma at postchemotherapy resection), and four achieved complete responses with chemotherapy and surgical resection of viable cancer. Thus, an overall favorable response was achieved in 22 patients (60%). Four additional patients had marker-negative non-resected residual masses. Eleven patients were considered treatment failures, including one who died early and another who succumbed to granulocytopenic sepsis and renal failure. Hematologic toxicity was the most common, with 26 patients (70%) having grade 4 granulocytopenia. After a median follow-up of 41 months, the actuarial two-year overall survival and progression-free survival were 64% and 58%, respectively. CONCLUSION: BOMP/EPI is active in poor-prognosis germ-cell tumors according to the IGCCC criteria. The results obtained compare favorably with those expected with conventional chemotherapy, and justify further studies. (+info)
A randomised phase III trial comparing consolidation treatment with further chemotherapy to chest irradiation in patients with initially unresectable locoregional non-small-cell lung cancer responding to induction chemotherapy. European Lung Cancer Working Party.
(77/7975)
PURPOSE: A phase III randomised trial was conducted in patients with non-metastatic unresectable non-small-cell lung cancer in order to compare, in responders to induction chemotherapy, consolidation treatment by further chemotherapy to chest irradiation. PATIENTS AND METHODS: A total of 462 untreated NSCLC patients were eligible for three courses of induction chemotherapy (MIP) consisting of cisplatin (50 mg/m2), ifosfamide (3 g/m2) and mitomycin C (6 mg/m2). It was proposed that objective responders be randomised to either three further courses of MIP or to chest irradiation (60 Gy; 2 Gy per fraction given over six weeks). RESULTS: An objective response rate of 35% was achieved; 115 patients (including 52% with initial stage IIIA and 44% with initial stage IIIB) were randomised to consolidation treatment, 60 of them to further chemotherapy and 55 to chest radiotherapy. There was no significant difference in survival between the two arms, with a respective median and two-year survival of 42 weeks (95% confidence intervals (95% CI: 35-51) and 18% (95% CI: 8-28) for chemotherapy and 54 weeks (95% CI: 43-73) and 22% (95% CI: 11-33) for irradiation. There was also no statistical difference for response duration between the two arms but chest irradiation was associated with a significantly greater duration of local control than chemotherapy (median duration times: 158 vs. 31 weeks, P = 0.0007). CONCLUSIONS: For non-metastatic unresectable NSCLC treated by an induction chemotherapy regimen containing cisplatin and ifosfamide, if an objective response is obtained, consolidation treatments by further chemotherapy or by chest irradiation result in non-statistically different survival distributions, although a better local control duration is observed with radiotherapy. (+info)
Cisplatin-topotecan-paclitaxel weekly administration with G-CSF support for ovarian and small-cell lung cancer patients: a dose-finding study.
(78/7975)
PURPOSE: Paclitaxel (PTX) and topotecan (TPT) have shown promising antitumor activity in both ovarian cancer (OC) and small-cell lung cancer (SCLC) patients. This phase I study was aimed at determining the maximum tolerable dose (MTD) of TPT given weekly over 30 min in combination with fixed doses of cisplatin (CDDP) and (PTX), and with G-CSF support. PATIENTS AND METHODS: Forty-four patients with OC (19) or SCLC (25), either chemo-naive (20) or pretreated (24) received CDDP 40 mg/m2, PTX 85 mg/m2 (one-hour infusion) and escalating TPT doses (starting from 0.75 mg/m2) in a 30-min infusion in weekly administration. Filgrastim 5 mg/kg was administered on days 3 to 5 of each week. RESULTS: Eight different dose levels were tested for a total of 295 delivered cycles. The dose escalation was interrupted at the TPT dose of 2.50 mg/m2. No toxic deaths occurred in this study. Grade 3 to 4 neutropenia, thrombocytopenia, and anemia occurred in 15 patients (36 cycles), seven patients (15 cycles), and four patients (five cycles), respectively. Severe vomiting and diarrhoea occurred in seven and four patients. Peripheral neuropathy was recorded in 11 patients (42 cycles), but it was never severe. An overall 11 of 19 (58%) OC and 11 of 25 (44%) SCLC patients obtained objective responses. Eight patients showed complete responses (three OC and three SCLC). Among the 20 chemo-naive patients, 9 of 11 (82%) OC and seven of nine (78%) SCLC responded. CONCLUSIONS: The CDDP/TPT/PTX weekly administration with filgrastim support represents a well-tolerated and active therapeutic approach in both chemo-naive and pretreated OC and SCLC patients. A weekly dose of TPT of 2.25 mg/m2 is recommended for the phase II study. (+info)
Loss of DNA mismatch repair facilitates reactivation of a reporter plasmid damaged by cisplatin.
(79/7975)
In addition to recognizing and repairing mismatched bases in DNA, the mismatch repair (MMR) system also detects cisplatin DNA adducts and loss of MMR results in resistance to cisplatin. A comparison was made of the ability of MMR-proficient and -deficient cells to remove cisplatin adducts from their genome and to reactivate a transiently transfected plasmid that had previously been inactivated by cisplatin to express the firefly luciferase enzyme. MMR deficiency due to loss of hMLH1 function did not change the extent of platinum (Pt) accumulation or kinetics of removal from total cellular DNA. However, MMR-deficient cells, lacking either hMLH1 or hMSH2, generated twofold more luciferase activity from a cisplatin-damaged reporter plasmid than their MMR-proficient counterparts. Thus, detection of the cisplatin adducts by the MMR system reduced the efficiency of reactivation of the damaged luciferase gene compared to cells lacking this detector. The twofold reduction in reactivation efficiency was of the same order of magnitude as the difference in cisplatin sensitivity between the MMR-proficient and -deficient cells. We conclude that although MMR-proficient and -deficient cells remove Pt from their genome at equal rates, the loss of a functional MMR system facilitates the reactivation of a cisplatin-damaged reporter gene. (+info)
Multi-institutional randomized clinical study on the comparative effects of intracavital chemotherapy alone versus immunotherapy alone versus immunochemotherapy for malignant effusion.
(80/7975)
The current prospective randomized study was designed to compare the effects of intracavitary (i.c.) chemotherapy vs immunotherapy vs immunochemotherapy for malignant effusion. Between 1992 and 1995, a total of 42 patients with malignant effusion were registered, and 41 patients were eligible for statistical analysis. The primary diseases of the eligible patients included 27 gastric, four colorectal, four pancreatic, three lung, two liver and one oesophageal cancers. The patients with malignant effusion were randomly assigned into one of three i.c. therapeutic regimens: chemotherapy alone with weekly injection of anticancer agents (ACAs: cisplatin, mitomycin-C, adriamycin, etc.) (Group A, n = 13); immunotherapy alone with weekly injection of streptococcal preparation OK-432 (Group B, n = 14); or immunochemotherapy with ACAs and OK-432 (Group C, n = 14). The response of the effusion, patient survival and the kinetics of cytokines in the effusion were compared. There were no differences in the patients' backgrounds. The side-effects of the regimens included pain, anorexia, fever, leucopenia and anaemia and there were no differences in their incidence among the three groups. One patient died after cisplatin (CDDP) administration in Group A. Cytologic examination revealed that tumour cells in the effusion disappeared in 23% of Group A cases, 36% of Group B cases and 36% of Group C cases. The malignant effusion did not disappear in any of the Group A cases; however, the effusion disappeared in 29% of Group B cases and 43% of Group C cases (P = 0.03, Group A vs Group C). Furthermore, the 50% survival period was 1.6 months for Group A, 2.4 months for Group B and 3.5 months for Group C. The 6-month survival rate was 7% for Group A, 6% for Group B and 34% for Group C, and the 1-year survival rate was 0%, 0% and 17% respectively (P = 0.048, Group A vs Group C by the log-rank test). The analysis of the cytokine kinetics revealed a prominent increase in the level of interleukin-6 in the effusion in Group C. These results suggest that i.c. immunochemotherapy with OK-432 and ACAs may be more beneficial than i.c. chemotherapy alone or immunotherapy alone. (+info)