In vitro schedule-dependent interaction between paclitaxel and SN-38 (the active metabolite of irinotecan) in human carcinoma cell lines

Paclitaxel and irinotecan are important new anticancer agents. The combination of these two agents has been considered for use against a variety of advanced solid tumors. Since the schedule-dependent effects of this combination may be crucial to its use, we studied the interaction of paclitaxel and SN-38 (the active metabolite of irinotecan) in various schedules in four human cancer cell lines in culture. Cell growth inhibition after 5 days was determined using an MTT assay. The effects of drug combinations at the IC₈₀ level were analyzed by the isobologram method. Simultaneous exposure to paclitaxel and SN-38 for 24 h produced antagonistic (subadditive and protective) effects in the human lung cancer cell line A549, the breast cancer cell line MCF7, and the colon cancer cell line WiDr, and produced additive effects in the ovarian cancer cell line PA1. Sequential exposure to paclitaxel for 24 h followed by SN-38 for 24 h, and the reverse sequence, produced additive effects in all four cell lines. These findings suggest that sequential administration, not simultaneous administration, may be the appropriate schedule for the therapeutic combination of paclitaxel and irinotecan. Continued preclinical and clinical studies should provide further insights and assist in determining the optimal schedule for this combination in clinical use. Received: 25 February 1997 / Accepted: 6 November 1997     

A long-term follow-up study on risk factors for hepatocellular carcinoma among Japanese patients with liver cirrhosis.

To identify virological parameters (serostatus of hepatitis B surface antigen [HBsAg] and antibodies to hepatitis C virus [anti-HCV], HCV genotypes and HCV-RNA titer) and other clinico-biological and lifestyle variables that may influence or predict the development of hepatocellular carcinoma (HCC) in cirrhosis, we followed 100 cirrhotic patients without HCC, who visited Kyushu University Hospital between 1985 and 1987, until the end of 1995 (follow-up rate: 98%; average follow-up period: 5.3 years). After elimination of 4 patients who developed HCC or were censored within the initial 6 months, 37 (39%) out of 96 patients developed HCC during follow-up. As compared with HBsAg(+) patients, anti-HCV(+) HBsAg(-) patients demonstrated significantly elevated HCC risk (adjusted hazard ratio [HR] = 5.85, 95% confidence interval [CI] 1.65-20.67). Genotype 1 HCV infection was not associated with increased risk compared with genotype 2 (HR = 0.64, 95% CI 0.21-1.99). For genotype 1 HCV infection, patients with HCV-RNA levels < 1 Meq/ml tended to present lower risk than patients with > or = 1 Meq/ml (P = 0.03). Male sex, advanced Child's class, lower serum albumin, and higher serum aminotransferase and alpha-fetoprotein were also found to be strong predictors. Overall, drinking and smoking habits were not associated with significantly elevated risk. Among virological parameters, anti-HCV positivity and, possibly high HCV-RNA titer, were predictive of HCC occurrence in cirrhosis in our clinical setting.     

Prednisolone plus low-dose aspirin improves the implantation rate in women with autoimmune conditions who are undergoing in vitro fertilization

Objective: To evaluate the effect of prednisolone plus low-dose aspirin (PSL/LDA) in women with autoimmune conditions who were enrolled in an IVF-ET program.

Design: A retrospective clinical study.

Setting: In vitro fertilization unit, Niigata University Hospital, Niigata, Japan.

Patient(s): Three hundred seven women who underwent IVF-ET between January 1996 and December 1997.

Intervention(s): Prednisolone (10 mg/d) and aspirin (81 mg/d) were administered to the women with autoantibodies who chose to participate.

Main Outcome Measure(s): Pregnancy and implantation rates with IVF-ET.

Result(s): Women undergoing IVF who had positive antinuclear antibodies, with or without antiphospholipid antibodies, had significantly lower pregnancy and implantation rates than did women without autoantibodies (14.8% versus 21.7% and 6.8% versus 10.4%, respectively). The administration of PSL/LDA to women with antinuclear antibodies significantly improved the outcome of IVF-ET (40.6% pregnancy rate and 20.3% implantation rate).

Conclusion(s): A high proportion of women who are undergoing IVF-ET have autoantibodies, which are associated with poor IVF outcomes. The administration of PSL/LDA to these women may improve their implantation rate.     

Cerulenin, an inhibitor of protein acylation, selectively attenuates nutrient stimulation of insulin release: a study in rat pancreatic islets

Nutrients such as glucose stimulate insulin release from pancreatic beta-cells through both ATP-sensitive K+ channel-independent and -dependent mechanisms, which are most likely interrelated. Although little is known of the molecular basis of ATP-sensitive K+ channel-independent insulinotropic nutrient actions, mediation by cytosolic long-chain acyl-CoA has been implicated. Because protein acylation might be a sequel of cytosolic long-chain acyl-CoA accumulation, we examined if this reaction is engaged in nutrient stimulation of insulin release, using cerulenin, an inhibitor of protein acylation. In isolated rat pancreatic islets, cerulenin inhibited the glucose augmentation of Ca2+-stimulated insulin release evoked by a depolarizing concentration of K+ in the presence of diazoxide and Ca2+-independent insulin release triggered by a combination of forskolin and phorbol ester under stringent Ca2+-free conditions. Cerulenin inhibition of glucose effects was concentration dependent, with a 50% inhibitory concentration (IC50) of 5 microg/ml and complete inhibition at 100 microg/ml. Cerulenin also inhibited augmentation of insulin release by alpha-ketoisocaproate, a mitochondrial fuel. Furthermore, cerulenin abolished augmentation of both Ca2+-stimulated and Ca2+-independent insulin release by 10 micromol/l palmitate, which causes palmitoylation of cellular proteins. In contrast, cerulenin did not attenuate insulin release elicited by nonnutrient secretagogues, such as a depolarizing concentration of K+, activators of protein kinases A and C, and mastoparan. Glucose oxidation, ATP content in islets, and palmitate oxidation were not affected by cerulenin. In conclusion, cerulenin inhibits nutrient augmentation of insulin release with a high selectivity. The finding is consistent with a prominent role of protein acylation in the process of beta-cell nutrient sensing.     

Calpain inhibitor inhibits secretory granule maturation and secretion of GH

Clathrin- and AP-1-coated buds are present on immature secretory granules of endocrine cells that mature into clathrin-uncoated granules. The mechanism of clathrin and adaptor protein uncoating has remained obscure. Benzyloxycarbonyl-L-leucyl-L-leucinal (ZLLal), a calpain inhibitor, reduced growth hormone (GH) secretion with intracellular accumulation, in a GH-secreting rat pituitary tumor cell. Pulse and chase demonstrated that ZLLal retarded the turnover of clathrin (Clt.H) and adaptins. ZLLal-treatment co-immunoprecipitated the increased amounts of GH with Clt.H and adaptins compared to control cells, suggesting the intracellular accumulation of immature secretory granules. Clt.H and adaptins were limited-proteolyzed by m-calpain in vitro, indicating that calpain may be involved partly in the maturation of secretory granules in endocrine cells via the process of clathrin uncoating.     

Serine protease inhibitors prevent alcoholic liver injury]

The hepatotoxic effects of alcohol have been described in detail, but factors responsible for its hepatotoxicity have only partially characterized. It now appears that Kupffer cell derived TNF-alpha participates in several aspects of alcoholic liver injury. On the other hand, protease inhibitors have been used successfully for treatment of intractable diseases in which TNF-alpha is involved in the pathogenesis, including ulcerative colitis and Crohn's disease. Here, we will review new evidence for the proposal that serine protease inhibitors prevents alcoholic liver injury via mechanisms dependent on Kupffer cell derived TNF-alpha.     

Vaccination of dendritic cells loaded with interleukin-12-secreting cancer cells augments in vivo antitumor immunity: characteristics of syngeneic and allogeneic antigen-presenting cell cancer hybrid cells.

Cancer immunotherapy by fusion of antigen-presenting cells and tumor cells has been shown to induce potent antitumor immunity. In this study, we characterized syngeneic and allogeneic, murine macrophage/dendritic cell (DC)-cancer fusion cells for the antitumor effects. The results showed the superiority of allogeneic cells as fusion partners in both types of antigen-presenting cells in an in vivo immunotherapy model. A potent induction of tumor-specific CTLs was observed in these immunized conditions. In addition, the immunization with DC-cancer fusion cells was better than that with macrophage-cancer fusion cells. Both syngeneic and allogeneic DC-cancer fusion cells induced higher levels of IFN-gamma production than macrophage-cancer fusion cells. Interestingly, allogeneic DC-cancer fusion cells were superior in that they efficiently induced Th1-type cytokines but not the Th2-type cytokines interleukin (IL)-10 and IL-4, whereas syngeneic DC-cancer fusion cells were powerful inducers of both Th1 and Th2 cytokines. These results suggest that allogeneic DCs are suitable as fusion cells in cancer immunotherapy. To further enhance the antitumor immunity in the clinical setting, we prepared DCs fused with IL-12 gene-transferred cancer cells and thus generated IL-12-secreting DC-cancer fusion cells. Immunization with these gene-modified DC-cancer fusion cells was able to elicit a markedly enhanced antitumor effect in the in vivo therapeutic model. This novel IL-12-producing fusion cell vaccine might be one promising intervention for future cancer immunotherapy.     

Gender difference in alcoholic liver injury]

Gender differences of alcoholic liver injury have been described previously, but mechanisms have only partially characterized. For example, it is known that females develop alcoholic liver injury more rapidly and to a greater extent than males. It now appears that estrogen participates in several aspects of this phenomenon. On the other hand, attention has been directed towards the effect of ethanol ingestion on Kupffer cell function, which is stimulated by gut-derived endotoxins via mechanisms dependent on increased gut permeability and the possible relationship between Kupffer cell and alcohol-induced liver injury.     

A case of panpleuropneumonectomy for diffuse pleural mesothelioma

A 58-year-old man was admitted to our hospital because of chest pain and dyspnea on July 15, 1999. A chest X-ray showed left pleural effusion, and a chest CT revealed left pleural effusion and diffuse pleural thickening. Because pleural fluid cytology and percutaneous needle pleural biopsy were negative for malignancy, thoracoscopic biopsy was performed on July 28. The biopsied specimen revealed malignant pleural mesothelioma (epithelial type). An operation was performed on August 16. First, mediastinal lymph node dissection was performed and we identified that there was no lymph node metastasis by frozen section diagnosis. Then panpleuropneumonectomy with combined resection of the diaphragm and pericardium was performed.