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K Tasaki

Publications and source records attributed to K Tasaki.

89 records · Page 5Linked to original sources
PubMedDate not supplied

Protein kinase C isozyme expression in human leukemia-lymphoma cell lines--an immunocytochemical study.

There have been an increasing number of reports describing a pivotal role for phosphorylation in cellular responses for cell differentiation and proliferation. We examined an immunocytochemical expression of protein kinase C(PKC) isozymes (type I, II, and III) in 22 leukemia-lymphoma cell lines. Of these cell lines, 21 expressed type II PKC and 17 showed the co-expression of both types II and III PKC in varying degree. The cell line without PKC activity showed far less [3H]-TdR uptake and no heterotransplantation in nude mice. Types II and III PKC appear to relate to cell proliferation in certain leukemia-lymphoma cell lines.

Antibodies, Monoclonal↗
PubMedDate not supplied

Drug interactions of zonisamide with phenytoin and sodium valproate: serum concentrations and protein binding.

The influence of co-medication with zonisamide (ZNS) on the serum concentration and protein binding of phenytoin (PHT) and sodium valproate (VPA) was studied in 21 pediatric patients. No significant correlation between the daily ZNS dose, and total serum concentrations, free concentrations or free fractions (FF) of PHT or VPA was observed. The patient study showed that changes in the FF of PHT and VPA were correlated more closely with the serum protein and bilirubin levels than changes in the ZNS dosage. An in vitro study revealed that the addition of ZNS caused decreases in the FF of PHT and VPA. However, these decreases were within the range of measurement error and were negligible. In conclusion, no significant effect of ZNS on the serum concentration or protein binding of PHT or VPA was demonstrated.

Adolescent↗
PubMedDate not supplied

Radiosensitivity of human breast cancer cells transduced with wild-type p53 gene is influenced by the p53 status of parental cells.

Induction of apoptosis with chemotherapeutic agents or radiation in tumours is frequently related to the status of those p53 gene of the tumours. To examine whether forced expression of the wild-type p53 gene in tumour cells can modulate their susceptibility to radiation and anti-cancer agents, we retrovirally transduced two types of human breast cancer cell lines, which respectively harboured a mutated p53 gene (OCUB-M) or wild-type p53 gene (YMB-1), with the wild-type p53 gene. Transduced cells which consistently expressed the wild-type p53 gene (OCUB-M/p53, YMB-1/p53) proliferated at the same rate as control cells which were transduced with the beta-galactosidase gene (OCUB-M/lacz, YMB-1/lacz). However, sensitivity to radiation was increased in OCUB-M/p53 cells but not in YMB-1/p53 cells. In vitro chemosensitivity to DNA-damaging anticancer agents such as cyclophosphamide and 5-fluorouracil was not influenced by the transduction of the wild-type p53 gene in either cells. Expression of the wild-type p53 gene in p53-mutated human breast cancer cells can therefore increase their sensitivity to radiation but not their chemosensitivity. Therapeutic effects following by the transduction of the wild-type p53 gene were not observed in breast cancer cells already bearing the wild-type p53 gene.

Antineoplastic Agents↗
PubMedDate not supplied

Electroporation-mediated transfer of cytokine genes into human esophageal tumors produces anti-tumor effects in mice.

Electroporation facilitates transfer of chemicals or plasmid DNA from extracellular milieu into cells by increasing the permeability of the cell membrane. Delivery of electric pulses to established tumors thereby can improve the susceptibility of tumors to an anti-cancer agent administered. We examined whether electroporation-mediated transfer of cytokine genes into solid tumors could produce anti-tumor effects in the tumor-bearing mice. Plasmid DNA containing cytokine genes were injected into human esophageal T.Tn tumors developed in nude mice and electric pulses were then delivered. Administration of murine GM-CSF or human IL-2 gene followed by electroporation significantly suppressed the subsequent growth of T.Tn tumors and prolonged the survival of the inoculated mice. In contrast, electroporation-mediated introduction of a control gene, human GM-CSF gene, whose products do not bind to murine GM-CSF receptors, did not achieve any anti-tumor effects. In vivo transfection of cytokine genes with electroporation could be a possible therapeutic strategy for established solid tumors.

Animals↗
PubMedDate not supplied

Discordant production of released exogenous protein and infectious virions from retrovirus-packaging cells used for gene transduction.

We examined the correlation between the amount of exogenous protein secreted and that of its viral transcript from PA317 packaging cells transduced with a cytokine gene. Amphotropic packaging cells for the retrovirus expressing murine interleukin-15 (IL-15) gene were cloned, and we examined 22 clones for both the amount of IL-15 secreted with enzyme-linked immunosorbent assay and the IL-15 transcript released as infectious virions by slot blot-hybridization analysis. The study revealed that there was no statistical correlation between them, and suggests that the integrated transcript is used discordantly. Thus, the examination of secreted protein from packaging cells cannot be substituted for laborious assays to determine the amount of virion transcripts when isolating high titer packaging cells.

Animals↗
PubMedDate not supplied

Antitumor effect of human pancreatic cancer cells transduced with cytokine genes which activate Th1 helper T cells.

We have examined antitumor effect of human pancreatic carcinoma cells (AsPC-1) retrovirally transduced with interleukin-12 (IL-12), IL-15 or IL-18 gene in nude mice. The tumor growth of IL-12-expressing AsPC-1 cells was significantly retarded and that of IL-15-expressing cells was also impeded compared with that of wild-type cells, although their in vitro cell growth remained unchanged. However, the expression of IL-18 in AsPC-1 cells did not generate any antitumor effect since the tumor growth of the transduced cells was the same as that of wild-type cells. Thus, the differential actions of these cytokines on non-T cells can generate a variety of antitumor effect in nude mice, although their actions on T cells lineage favor the stimulation of Th1-type helper T cells.

Animals↗
PubMedDate not supplied

Impaired tumorigenicity and decreased liver metastasis of murine neuroblastoma cells engineered to secrete interleukin-2 or granulocyte macrophage colony-stimulating factor.

We have examined the antitumor effect of murine neuroblastoma cells (C1300) engineered to produce cytokines. Retrovirally transduced cells with human interleukin-2 (IL-2) or murine GM-CSF gene, but not murine IL-4 gene, abolished their tumorigenicity in syngeneic mice, although their in vitro growth rate and expression of class I antigens of the major histocompatibility complex were unchanged. Inoculation of wild-type cells into the mice, which had rejected IL-2 or GM-CSF producers, did not develop tumors, indicating that protective immunity was induced. In an experimental hematogenous metastasis model, we found that the numbers of metastatic foci in the liver caused by intravenous administration of IL-2 or GM-CSF producers were significantly reduced compared with those by the injection of wild-type or vector virus-transduced cells. No significant differences in their adhesiveness to extracellular matrices and ability to differentiate were observed among parent and transduced cells. Thus, these results indicate that IL-2 or GM-CSF secretion, in the vicinity of neuroblastoma cells, produced antitumor effect and reduced metastatic ability.

Animals↗
PubMedDate not supplied

Inhibition of experimental lung metastasis of murine colon carcinoma cells depends on the amount of interleukin-2 secreted from the transduced cells.

We examined the antitumor effect of low and high interleukin-2 (IL-2) producers of murine colon carcinoma cells (Colon 26) which were generated by transduction with IL-2 gene in an experimental lung metastasis model using syngeneic mice. Intravenous injection of the low IL-2 producer cells formed multiple lung metastatic foci and the survival of the mice was not different from that of the mice injected with wild-type cells. However, the mice administrated with the high producer cells survived significantly longer. Subcutaneous inoculation of the low producers, although it caused the development of local tumors at the inoculation sites in some of the mice tested, inhibited lung metastasis of wild-type cells subsequently inoculated and prolonged the survival of the mice rechallenged with Meth A cells, syngeneic fibrosarcoma cells. In contrast, inoculation of the high producers did not cause the development of subcutaneous tumors and inhibited the experimental metastasis of parental but not Meth A cells inoculated thereafter. Thus, the amount of secreted IL-2 from tumor cells differentially influences antitumor effects by inducing tumor specific and nonspecific immunity.

Animals↗
PubMedDate not supplied

Induction of T cell dependent acquired immunity in syngeneic mice by the combined expression of interleukin-4 and granulocyte macrophage-colony stimulating factor gene in murine colon carcinoma cells.

The inoculation of cytokine-producing tumor cells into syngeneic animals can produce antitumor effects. We previously reported that injection of a mixed population of murine colon carcinoma (Colon 26) cells transduced with interleukin-4 (IL-4) gene with granulocyte macrophage-colony stimulating factor (GM-CSF) gene developed subcutaneous tumors in syngeneic mice, but these tumors thereafter regressed spontaneously (Oncology 1997;54:69-73). In this study, we found the generation of tumor-specific acquired immunity in the mice which had rejected the tumors of a mixed population of IL-4 and GM-CSF producer cells, and that the immunity was mediated by mature T cells. Moreover, local secretion of both IL-4 and GM-CSF in the vicinity of tumors was found to be crucial for this rejection. These data suggest that enhanced host defense brought about by the combined expression of IL-4 and GM-CSF genes in tumor cells is a potential therapeutic strategy.

Animals↗
PubMedDate not supplied

Inhibition of peritoneal dissemination of murine colon carcinoma cells by administrating retrovirus harboring IL-2 gene.

We have examined the antitumor effect of the retrovirally expressed interleukin-2 (IL-2) gene in murine colon carcinoma cells (Colon 26) on a disseminated model within the peritoneal cavity. Intraperitoneal injection of IL-2-producing Colon 26, but not wild-type cells, into syngeneic mice did not cause animal death and conferred T-cell-dependent, tumor-specific protective immunity on the inoculated mice. Direct administration of the retrovirus harboring IL-2 gene into the peritoneal cavity of the mice that had intraperitoneal tumor of wild-type cells significantly prolonged the survival of the mice compared with that of the mice that received control retrovirus. In the surviving mice treated with the retrovirus we also observed the induction of protective immunity with tumor specificity. Integrated retrovirus DNA was not detected in any organs examined. Thus, in vivo IL-2 gene transfer by retrovirus enabled tumor-bearing mice to generate antitumor immunity without unnecessary retroviral insertion into host genome.

Adenocarcinoma↗