Biomedical subjects

T Ochiai

Publications and source records attributed to T Ochiai.

366 records · Page 21Linked to original sources

PubMedDate not supplied

Study of irradiation effects on cytokine secretion from retrovirally-transduced tumor cells: a model for tumor vaccination.

We have examined the effects of irradiation on the cytokine secretion from genetically modified human esophageal and gastric carcinomas. Both cell lines were transduced retrovirally to secrete interleukin-2, interleukin-6 and granulocyte-macrophage colony-stimulating factor, respectively. The metabolism of all the transduced cells was partially inhibited by 6 Gy, and greatly inhibited by 20 Gy irradiation. Cytokine productions, however, was not affected by 6 Gy in many cases, and continued to be detected even after 60 Gy irradiation. The analysis of the dose and time of irradiation in each cytokine producer is useful for the designing of tumor vaccine using cytokine gene transfer.

Cell Division↗

PubMedDate not supplied

Adenosquamous carcinoma with different morphologic and histologic components arising from the intrahepatic bile duct: report of a case.

A very rare form of adenosquamous carcinoma arising from the intrahepatic bile duct which had diverse morphologic and histologic components is presented. A 77-year-old female complained of relapsing febrile attack accompanied by upper abdominal pain. From the imaging studies, which revealed an atrophic left lobe with dilated intrahepatic bile duct, cholangiocarcinoma constricting the orifice of B3 was considered the most likely diagnosis. Surgery, which included resection of the left hepatic and caudate lobes with lymph node dissection, revealed an atrophic lateral segment indicating recurrent inflammation. Pathologic examination revealed a combined tumor composed of papillary squamous cell carcinoma arising at the orifice of the lateral inferior segmental bile duct and intramucosal adenocarcinoma spreading distal to the polypoid tumor. Two different components were connected with a thin stalk, but there was no apparent transitional zone. Contrary to ordinary mass-forming adenosquamous carcinoma in the liver, which is reported to pursue a very rapid, fatal course, our patient made an uneventful recovery and has remained in good health without recurrence for 2 years and 3 months since surgery.

Aged↗

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

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↗