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Biomedical subjects

N Saijo

Publications and source records attributed to N Saijo.

At least 127 records · Page 7Linked to original sources
PubMed1997

Proximal 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit gene is involved in cisplatin-induced transcriptional up-regulation in a lung cancer cell line SBC-3.

The contribution of the 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit (gamma-GCSh) gene to cisplatin-induced transcriptional up-regulation was studied using various human growth hormone reporter constructs which were transfected to a human lung cancer cell line SBC-3. Cisplatin at the concentration of 3 microM increased the transcriptional activity of the longest sequence from -1,413 to +91 bp of the gamma-GCSh gene to 246% of that in non-exposed cells. The distal sequence from -1,413 to -193 bp was shown to negatively regulate transcriptional activity in both cisplatin-exposed and non-exposed cells using deletion and thymidine kinase (TK) promoter-linked constructs. Cisplatin increased the transcriptional activity of the proximal GC-rich sequence from -192 to +91 bp to 340%, of which magnitude was the maximum among deletion constructs. A deletion from -108 to -28 bp, or +34 to +91 bp significantly decreased cisplatin-induced increases in transcriptional activity from 258 to 105%, or 340 to 160%, respectively. When the sequence from -108 to -22 bp, or +26 to +91 bp was linked to the heterologous TK promoter, cisplatin increased the transcriptional activity to 171 or 181%, respectively, from that of 128 or 137%, respectively, in non-exposed cells. These findings indicate that the proximal sequence from -192 to +91 bp of the gamma-GCSh gene, especially from -108 to -28 bp, and +34 to +91 bp, is involved in cisplatin-induced transcriptional up-regulation in SBC-3 cells.

Antineoplastic Agents↗
PubMed1997

Evaluation of synergism by a novel three-dimensional model for the combined action of cisplatin and etoposide on the growth of a human small-cell lung-cancer cell line, SBC-3.

Although the combination of cisplatin and etoposide has been used as standard therapy for small-cell lung cancer, it is difficult to demonstrate combination effects between cisplatin and etoposide in vitro. We therefore adopted a 3-dimensional (3-D) model to analyze the combination effects of anticancer drugs, and compared the results of analysis by the new 3-D model with those obtained from traditional 2-D models for the cisplatin-etoposide combination. In this study, using a human small-cell lung-cancer cell line (SBC-3), 3-D model analysis clearly identified a relationship depending on the concentrations of both drugs, and demonstrated that peak synergy occurred at the higher concentrations of cisplatin and etoposide. Antagonistic interactions were noted with a nadir at low concentrations of etoposide and cisplatin. In contrast, 2-D models such as combination index and isobologam analysis fail to characterize the complex interactions between cisplatin and etoposide, since their joint effects are concentration-dependent. Combination index (CI) plots show that synergy is evident only for molar ratios of cisplatin: etoposide of 2:1 to 1:5. On isobologram analysis, synergy could be detected when great inhibitory effects on cell growth were present (high endpoint), but not with small inhibitory effects (lower endpoints). Thus, either synergy or antagonism may occur, but depend on the selection of variables, such as the molar ratios or the endpoints chosen for the experiments. This could explain the inconsistency in the in vitro combination effects reported to date. The 3-D model, which compensates for the above deficiencies of 2-D models, can facilitate rigorous analysis of drug interactions over the entire clinical dose range, using microcomputers and sophisticated graphics programs. This direct and pragmatic method offers investigators a practical new tool with which to analyze drug combinations for cancer chemotherapy.

Antineoplastic Agents↗
PubMed1997

Identification of cis-acting DNA elements of the human gamma-glutamylcysteine synthetase heavy subunit gene.

Transcriptional activity of the 5'-flanking sequence of the human gamma-glutamylcysteine synthetase heavy subunit (gamma-GCSh) gene was investigated in COS7 cells transfected with hGH reporter constructs having successively deleted 5'-flanking sequence of the gamma-GCSh gene. Transcriptional activity was determined by the amounts of hGH secreted from the reporter constructs. Deletion of the sequence from -1,413 to -664 or -315 base pairs (bp) increased transcriptional activity from 100 to 138 or 136%. Further deletion from -315 to -241 bp, which contained an AP1 site, decreased transcriptional activity to 87%. Mutations introduced into the AP1 decreased transcriptional activity from 136 to 105%. These findings suggested that the AP1 increased transcriptional activity. When the sequence from -241 to -192 bp was deleted, transcriptional activity was restored from 87 to 128%. When this sequence was linked to the thymidine kinase promoter, it also decreased transcriptional activity by 38%. Deletion from -192 to -149, -116, or -108 bp did not significantly alter transcriptional activity. Further deletion of the GC-rich sequences from -108 to -70 and -28 bp dramatically decreased transcriptional activity from 135 to 87 and 34%, respectively. These findings indicate that multiple DNA elements, especially those in the proximal GC-rich sequences, are involved in the regulation of transcriptional activity of the gamma-GCSh gene.

Base Composition↗
PubMed1997

Interleukin-2 gene transduction into freshly isolated lung adenocarcinoma cells with adenoviral vectors.

We evaluated the efficiency of gene transduction and of gene expression by adenoviral vectors in human lung adenocarcinoma cells. Freshly isolated cancer cells were collected from pleural effusions in adenocarcinoma patients by centrifugation with a Percoll gradient. Adenoviral vectors resulted in effective gene transduction into human lung cancer cell lines and into freshly isolated lung adenocarcinoma cells. In an experiment using the beta-galactosidase (LacZ) gene, the Adex1CA vector with a regulatory sequence of chicken beta-actin as promoter and an enhancer derived from cytomegalovirus produced a higher transduction ratio and greater expression levels than adenoviral vectors with other promoter systems. Transduction with Adex1CA vectors containing the human interleukin-2 (IL-2) gene (Adex1CAhIL-2) resulted in enhanced secretion of IL-2 from gene-modified lung cancer cells. Treatment with normal human serum inhibited gene transduction by Adex1CAhIL-2 but did not inhibit gene expression after transduction by Adex1CAhIL-2. The secretion of IL-2 from the gene-modified cells, which were irradiated at 100 Gy before transduction, continued for 8 days. In a mouse model, the intrapleural injection of IL-2 gene-modified 3LL cells transduced by Adex1CAhIL-2 could cure the pre-existing lung tumours with malignant pleural effusions to induce tumor-specific immunity. But these therapies did not show any therapeutic benefit on the pre-existing tumor in subcutaneous region. These data suggest a potentially useful but limited clinical role of Adex1CAhIL-2 in gene therapy for lung cancer patients.

Adenoviridae↗
PubMed1997

In vitro and in vivo modulation by rhizoxin of non-P-glycoprotein-mediated vindesine resistance.

Rhizoxin is an antineoplastic drug that inhibits tubulin polymerization. In this study, we demonstrated that rhizoxin was approximately twice as active in vitro against a human small-cell lung cancer cell line with non-P-glycoprotein-mediated resistance to vindesine, H69/VDS, as against its parental line, H69. Tubulin polymerization in H69/VDS, demonstrated by Western blot analysis, was inhibited markedly by rhizoxin compared with that in H69, in a concentration-dependent manner. A drug-accumulation study showed that the intracellular rhizoxin level in H69/VDS was 15% lower than that in H69, whereas efflux from H69/VDS was enhanced slightly. These results indicate that enhanced inhibition of tubulin polymerization rather than increased intracellular drug concentration accounted for the higher sensitivity of H69/VDS to rhizoxin. In an experiment using mice with severe combined immunodeficiency and inoculated subcutaneously with H69/VDS, in vivo tumor growth was reduced markedly by three intermittent intraperitoneal doses of rhizoxin compared with that in mice inoculated with H69. Three weeks after the last rhizoxin dose, the relative treated/untreated tumor volumes were 0.29 for H69, but only 0.06 for H69/VDS, indicating that H69/VDS regrowth was minimal even after a 3-week treatment-free period. In conclusion, rhizoxin conquers vindesine resistance of a human small-cell lung cancer cell line in vitro and in vivo.

Animals↗
PubMed1997

Dose-intensive chemotherapy in extensive-stage small-cell lung cancer.

The importance of the dose intensity of chemotherapy in achieving maximal therapeutic effect has recently been reported for several chemosensitive malignant diseases, with Murray et al. reporting that intensive weekly chemotherapy using the cisplatin, vincristine, doxorubicin, and etoposide (CODE) regimen in small-cell lung cancer (SCLC) is very effective. However, leukopenia is the major obstacle to delivering the planned dose in intensive regimens. Therefore, we investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) could allow full drug doses to be given as scheduled, thereby improving the final outcome. Extensive-stage (ES) SCLC patients were randomized to receive either CODE alone or CODE with rhG-CSF, with the CODE regimen consisting of cisplatin given i.v. at 25 mg/m2 weekly for 9 weeks; vincristine given i.v. at 1 mg/m2 during weeks 1, 2, 4, 6, and 8; and doxorubicin given i.v. at 40 mg/m2 and etoposide given i.v. at 80 mg/m2 for 3 days during weeks 1, 3, 5, 7, and 9, rhG-CSF at 50 micrograms/m2 was given s.c. on the days on which cytotoxic drugs were not given. From May 1989 to September 1991; 64 patients were enrolled in the study, of whom 63 were analyzable (31 for CODE alone and 32 for CODE with rhG-CSF). No difference in any of the patients' characteristics except gender was found between the two groups. The complete response (CR) rate was 34% in the CODE with rhG-CSF group and 23% in the CODE alone group; the median survival was 59 and 32 weeks, respectively, in these groups (P = 0.004). Therefore CODE with rhG-CSF improved the survival of ES SCLC patients. On the basis of these results a phase III study to determine whether CODE with rhG-CSF would increase survival as compared to the standard regimen in ES SCLC was designed by the Japan Clinical Oncology Group.

Adult↗
PubMed1997

Chemotherapy: the more the better? Overview.

Although numerous clinical trials of high-dose chemotherapy have been performed, few have demonstrated that such strategies are statistically significantly better than other forms of therapy. Application of dose-intensive and/or high-dose chemotherapy should be limited to drug-sensitive tumors, with primary end points being increased cure rates or prolonged survival. This should be confirmed by randomized clinical trials comparing dose-intensive and/or high-dose chemotherapy with standard therapeutic modalities.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Anti-tumour activities of a new benzo[c]phenanthridine agent, 2,3-(methylenedioxy)-5-methyl-7-hydroxy-8-methoxybenzo[c]phena nthridini um hydrogensulphate dihydrate (NK109), against several drug-resistant human tumour cell lines.

Drug resistance is one of the problems severely limiting chemotherapy in cancer patients. Thus, it is very important to develop new drugs that are effective against drug-resistant tumour cells. The novel anti-tumour agent NK109 has been developed from benzo[c]phenanthridine derivatives by Nippon Kayaku (Tokyo, Japan). We have confirmed that NK109 shows anti-tumour effects against a number of human tumour cell lines by inhibiting DNA topoisomerase II activity through the stabilization of the cleavable complex. Further, its efficacy against several drug-resistant tumour cell lines was also shown. NK109 showed potent anti-tumour activity against doxorubicin-resistant human tumour cell lines that have a typical multidrug resistance phenotype caused by P-glycoprotein. NK109 was not pumped extracellularly by P-glycoprotein and, consequently, NK109 accumulated in resistant cells. Cisplatin-resistant human tumour cell lines, which demonstrated decreased cisplatin accumulation, were sensitive to NK109. NK109 non-cross-resistance was confirmed using xenografts of tumour cells that were resistant to cisplatin in SCID mice. Furthermore, etoposide-resistant cells, with decreased topoisomerase II activity, were markedly sensitive to NK109 when compared with their parent cells, suggesting the possibility that the cytotoxic mechanism of NK109 differs from that of etoposide. In conclusion, NK109 is a very promising new anti-tumour drug for clinical use, because the efficacy of NK109 is not susceptible to several known molecular alterations that are associated with drug resistance. A clinical study of this compound is now in progress in Japan.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Phase I study of sequentially administered topoisomerase I inhibitor (irinotecan) and topoisomerase II inhibitor (etoposide) for metastatic non-small-cell lung cancer.

We conducted a phase I study of irinotecan (CPT-11) and etoposide (VP-16) given sequentially to untreated patients with metastatic non-small-cell lung cancer. Arm A: CPT-11 was given over 90 min on days 1-3 and VP-16 was given over 60 min on days 4-6. Arm B: VP-16 was given on days 1-3 and CPT-11 on days 4-6. G-CSF was given to all patients daily on days 7-17. Twenty-seven patients were entered randomly at the two arms. The major dose-limiting toxicities in arms A and B were granulocytopenia and diarrhoea. Transient elevations of transaminases and bilirubin were observed in both arms. The degree of the toxicities did not differ between the two arms. The maximum tolerated doses (MTDs) were 60 mg m-2 CPT-11 and 60 mg m-2 VP-16 in both arms. Of the 13 patients who received more than two cycles, two out of five achieved partial response (PR) at the first level of arm A and one out of four achieved PR at the second level of arm B. We conclude that these schedules of sequential CPT-11 and VP-16 administration were inappropriate because of severe toxicities.

Adult↗
PubMed1997

Prognostic factors and prognostic staging system for small cell lung cancer.

This study was performed to assess the prognostic factors and the predictors of long-term (3-year) survival in patients with small cell carcinoma of the lung, accrued in one randomized trial, and to define patient subgroups showing significantly different survivals using recursive partitioning and amalgamation analysis. A total of 300 patients with small cell carcinoma of the lung were entered into a randomized study comparing cyclophosphamide, adriamycin and vincristine (CAV), cisplatin and etoposide (PE) and alternating treatments of CAV and PE. Of these, 286 patients were analysed for the present study of prognostic factors. Multivariate analysis showed that poor performance status (2-3) (P = 0.0001), extensive disease (P = 0.0015) and abnormally elevated serum lactate dehydrogenase (P = 0.0001) and alkaline phosphatase (P = 0.0013) were independently adverse pretreatment prognostic factors. Of limited disease patients, performance status (P = 0.029) and white blood cell count (P = 0.044) had a significant influence on the probability of 3-year disease-free survival. Using recursive partitioning and amalgamation analysis, three classes of similar prognosis were identified: the most favorable class was defined by knowledge of lactate dehydrogenase (normal), performance status (0-1) and serum sodium levels (normal) with median survival time of 16.0 months, and the class with the poorest prognosis was defined by knowledge of lactate dehydrogenase (elevated) and performance status (2-3) (median survival time 6.6 months). The intermediate class had a median survival time of 9.4 months. In conclusion, this subclassification system will be used for the design, implementation and interpretation of clinical studies as well as decision-making in individual patients.

Adult↗
PubMed1997

p16INK4 expression is associated with the increased sensitivity of human non-small cell lung cancer cells to DNA topoisomerase I inhibitors.

Inactivation of p16INK4, an inhibitor of cyclin-dependent kinases 4 (CDK4) and 6 (CDK6), may be essential for oncogenesis in non-small cell lung cancer (NSCLC). We examined the sensitivity of two clones of p16INK4-transfected NSCLC cell line with homozygous deletion of p16INK4, A549/p16-1 and 2, to DNA topoisomerase I (topo I) inhibitors. A549/p16-1 and -2 showed 7.7- and 9.1-fold increases in sensitivity to CPT-11 (11,7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin ), respectively, compared with A549 cells. Ectopic p16INK4-expressing cells also showed approximately 4.0-fold increase in sensitivity to SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of CPT-11, compared to the parent cells. The topo I-mediated DNA relaxation activities of ectopic p16INK4-expressing cells were approximately 5 times higher than those of the parent cells. Northern and western blot analyses indicate that these increased topo I activities of ectopic p16INK4-expressing cells were due to an elevated topo I mRNA level and an increase in topo I protein. The chemosensitivity to topo I inhibitors, topo I mRNA level, protein content and activity of a p16INK4 revertant, lacking functional p16INK4, tended to be restored toward those of the parental phenotype to some extent. These results suggest that p16INK4 expression is closely associated with the increased sensitivity of ectopic p16INK4-expressing NSCLC cells to topo I inhibitors. The up-regulation of topo I mRNA level, protein content and activity may be responsible for this hypersensitivity.

Antineoplastic Agents, Phytogenic↗
PubMed1997

In vitro enhancement of antitumor activity of a water-soluble duocarmycin derivative, KW-2189, by caffeine-mediated DNA-repair inhibition in human lung cancer cells.

Duocarmycins, including KW-2189, bind in the minor groove of double-stranded DNA at A-T-rich sequences, followed by covalent bonding with N-3 of adenine in preferred sequences. We examined the effect of DNA-repair modulators, such as caffeine and aphidicolin, on the cytotoxicity of duocarmycins towards human lung cancer cells, as determined by dye formation assay. Caffeine (0.5 or 1 mM), but not aphidicolin, enhanced the growth-inhibitory activity of KW-2189, DU-86, and duocarmycin SA. Caffeine inhibited repair of DNA strand breaks induced by KW-2189, as assayed by the alkaline elution technique. This suggests that duocarmycin-induced DNA strand breaks, which are potentially lethal to cells, are repaired through a caffeine-sensitive pathway.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Effect of glutathione depletion on cisplatin resistance in cancer cells transfected with the gamma-glutamylcysteine synthetase gene.

Overexpression of the human gamma-glutamylcysteine (gamma-GCS) gene resulted in cisplatin resistance with an increased glutathione (GSH) content, increased ATP-dependent glutathione S-conjugate export pump (GS-X pump) activity and decreased platinum accumulation in human lung cancer cells transfected with a gamma-GCS cDNA expression vector, as we previously reported. In this study, we examined the effects of buthionine sulfoximine (BSO), a specific inhibitor of gamma-GCS, to determine whether GSH depletion alters cisplatin resistance in a gamma-GCS-transfected cell line, SBC-3/GCS. In the presence of 10 microM BSO for 4 days, SBC-3/GCS still showed resistance to cisplatin, although it was partially reversed. Under these conditions, GS-X pump activity remained up-regulated in spite of low GSH content, and the platinum content was decreased. These data suggest that the GS-X pump itself influences cisplatin resistance, as well as cellular GSH content.

Aminoacyltransferases↗
PubMed1997

Interferon-gamma-inducing factor gene transfection into Lewis lung carcinoma cells reduces tumorigenicity in vivo.

To investigate the immunoregulatory effect of murine interferon-gamma-inducing factor (mIGIF), we transfected Lewis lung carcinoma (LLC) cells with a mammalian expression vector containing the mIGIF complementary DNA. The culture medium of the transfectant cells stimulated interferon-gamma (IFN-gamma) production by spleen cells in vitro in the presence of anti-CD3 antibody and markedly potentiated the effect of interleukin-12 (IL-12) on IFN-gamma production by spleen cells. mIGIF transfectant cells showed reduction of tumorigenicity and induction of an in vivo immuno-protective effect against the parental LLC cells. To examine the combined effect of systemic administration of recombinant IL-12 (rIL-12) and local mIGIF on the tumorigenicity, mice were challenged with LLC or transfectant cells on day 0, and the tumor-bearing mice were injected with 50 ng of rIL-12 intraperitoneally from day 7 to 11. Systemic rIL-12 showed an anti-tumor effect. However, mIGIF gene expression did not potentiate this effect of systemic rIL-12 in vivo.

Animals↗
PubMed1997

Phase II study of irinotecan and etoposide in patients with metastatic non-small-cell lung cancer.

PURPOSE: To determine the effects of irinotecan (CPT-11) given in combination with etoposide (VP-16) in metastatic non-small-cell lung cancer (NSCLC), to evaluate response and survival rates, and to determine the qualitative and quantitative toxicities of the combination chemotherapy. PATIENTS AND METHODS: Sixty-one metastatic NSCLC patients received concurrent administration of CPT-11 and VP-16 for 3 days with recombinant human granulocyte colony-stimulating factor (rhG-CSF) support. RESULTS: Fifty-nine patients were assessable for response and all 61 patients were assessable for toxicity and survival. Fifty-six patients were treated with two or more courses of chemotherapy. Thirteen patients achieved a partial response (PR), 36 showed no change (NC), and 10 showed progressive disease (PD). The overall response rate was 21.3% (95% confidence interval, 12.9% to 33.1%). The median duration of PRs was 141 days (range, 62 to 299). Of the hematologic toxicities, 14 (23%) and 24 (39%) patients experienced grade 3 or 4 leukopenia and neutropenia, respectively. The toxicities were feasible. Treatment-related death occurred in one patient who suffered hypovolemic shock induced by hematemesis. The median survival time was 10.0 months and the 1-year survival rate was 36.1%. CONCLUSION: Combination chemotherapy with concurrent administration of CPT-11 and VP-16 with rhG-CSF support was only modestly effective against metastatic NSCLC, with feasible toxicities of moderate diarrhea and pulmonary toxicity. The results were equivalent to those expected with either cisplatin-based chemotherapy or with CPT-11 alone.

Adenocarcinoma↗