Hiroshi Neda

In vivo gene delivery to tumor cells by transferrin-streptavidin-DNA conjugate

To target disseminated tumors in vivo, transgenes [ β‐galactosidase gene, green fluorescence protein (GFP) gene, herpes simplex virus thymidine kinase (HSV‐TK)] were conjugated to transferrin (Tf) by a biotin‐streptavidin bridging, which is stoichiometrically controllable, and Tf receptor (Tf‐R) affinity chromatography, which selects Tf conjugates with intact receptor bindings sites from reacting with the linker. Tf‐β ‐galactosidase plasmid conjugate thus constructed was specifically transfected to human erythroleukemia cells (K562) via Tf‐R without the aid of any lysosomotropic agents. The transfection efficiency of the conjugate was superior to those of lipofection (1% staining) and retroviral vector (5%) and slightly lower than that of adenovirus (70%). The high level of expression with our conjugate was confirmed using other tumor cells (M7609, TMK‐1) whereas in normal diploid cells (HEL), which express low levels of Tf‐R, expression was negligible. When GFP gene conjugates were systemically administered through the tail vein to nude mice subcutaneously inoculated with tumor, expression of GFP mRNA was found almost exclusively in tumors and to a much lesser extent in muscles, whereas GFP revealed by fluorescence microscopy was detected only in the former. To exploit a therapeutic applicability of this method, suicide gene therapy using Tf‐HSV‐TK gene conjugate for massively metastasized k562 tumors in severe combined immunedeficient mice was conducted, and a marked prolongation of survival and significant reduction of tumor burden were confirmed. Thus, this method could also be used for gene therapy to disseminated tumors.—Sato, Y., Yamauchi, N., Takahashi, M., Sasaki, K., Fukaura, F., Neda, H., Fujii, S., Hirayama, M., Itoh, Y., Koshita, Y., Kogawa, K., Kato, J., Sakamaki, S., Niitsu, Y. In vivo gene delivery to tumor cells by transferrin‐streptavidin‐DNA conjugate. FASEB J. 14, 2108–2118 (2000)

Serum tumor necrosis factor activity in inflammatory bowel disease

Serum tumor necrosis factor (TNF) levels in 33 patients with inflammatory bowel disease (IBD) were measured by using a sensitive enzyme immunoassay. Four of five Crohns diseases (CD) and nine of twenty eight ulcerative colitis (UC) had elevated levels of serum TNF. In active CD or UC, a greater fraction of patients studied had significantly increased serum TNF levels (3/3 for CD and 8/11 for UC). Production of TNF by peripheral blood monocytes when stimulated by lipopolysaccharide was also increased in these patients and correlated with their serum TNF levels. These results suggest that TNF may have some pathoetiological meaning in IBD.

Cytotocidal Mechanism of TNF: Effects of Lysosomal Enzyme and Hydroxyl Radical Inhibitors on Cytotoxicity

The participation of lysosomal enzymes, hydroxyl radicals, and mitochondrial respiration in the cytocidal effect of TNF on tumor cells was investigated. The cytotoxicity of TNF on L-M cells was clearly reduced by lysosomotropic agents, DMSO (hydroxyl radical scavenger), NDGA (lipoxygenase inhibitor), and sodium azide (mitochondrial respiration inhibitor). The results suggest that lysosomal enzyme and hydroxyl radicals play an important triggering role in the destruction of tumor cells by TNF, and that the process of destruction might require ATP.

Synergistic Cytotoxicity of Recombinant Human TNF and Various Anti-Cancer Drugs

A synergistic increase in the cytotoxic effects of recombinant human tumor necrosis factor (rH-TNF) and anti-cancer drugs was demonstrated in vitro. The cytotoxicity of rH-TNF against L-M cells in combination with Mitomycin C (MMC), Adriamycin (ADM), Cytosine arabinoside (Ara-C), Actinomycin D (ACD), Daunomycin (DM), Cisplatin (CDDP), Vincristine (VCR), and 5-Fluorouracil (5FU), based on the concentration necessary for 50% inhibition of cell growth (IC50), was 4 to 347 times as high as that of rH-TNF alone. The results suggest that combination therapy including rH-TNF and anti-cancer drugs may be of value in the treatment of malignancy in human patients.

Recombinant Human Tumor Necrosis Factor Causes Regression in Patients with Advanced Malignancies

Fifteen patients with advanced solid tumors of various types were treated by the intratumoral administration of recombinant human tumor necrosis factor (rH-TNF). The treatment appeared to benefit the 4 cases of superficial tumors: there were 1 complete response, 1 partial response and 2 minor responses. In all 11 patients with deep-seated tumors, including 6 cases of pancreatic cancer, 4 of liver cell cancer and 1 of metastatic liver tumor, no tumor regression was observed, but progression stopped in all these tumors. Seven of the 11 with deep-seated tumors showed a decrease in tumor markers and/or the development of tumor necrosis. Fever, hypotension and fatigue were the main clinical side effects. No significant changes were found in hematologic, renal or liver parameters. These results suggest that administration of rH-TNF to the tumor site has the potential for controlling local tumor growth.

Signalling pathway of tumor necrosis factor in normal and tumor cells

SummarySeveral aspects of the activity and effects of tumor necrosis factor (TNF) were investigated to gain further insight into its cytotoxic mechanism. The relation between number of TNF receptors and TNF susceptibility of both tumor cells and normal cells was studied, utilizing a specific binding assay. Among the tumor cells, a fairly close correlation (r=0.855) was observed between receptor number and sensitivity to TNF. No cytotoxic effect by TNF was observed on any of the normal cells tested, even though TNF receptors were shown to be present, and cell proliferation was apparently stimulated by TNF in some cases. TNF internalization and intracellular distribution were studied by pulse-labelling and Percoll density gradient centrifugation. In L-M (murine tumorigenic fibroblasts, highly sensitive to TNF cytotoxicity) cells and HEL (human embryonic lung cells, non-sensitive to TNF cytotoxicity) cells, receptor-bound 125I-labelled recombinant human TNF was rapidly internalized and delivered to lysosomes within 15–30 min, and this was followed by degradation and release into the culture medium. The presence of either a cytoskeletal disrupting agent or a lysosomotropic agent was observed to inhibit the cytotoxic effect of TNF, thus also indicating that TNF internalization, followed by delivery to lysosomes, is essential in the cytolytic mechanism of TNF.As observed by [3H]uridine incorporation, TNF did not affect RNA synthesis in L-R cells (TNF-resistant cell lines derived from L-M cells) and HEL cells, but markedly stimulated (by 3.5 times) RNA synthesis in L-M cells.

Therapeutic Effect of Endogenous Tumor Necrosis Factor on Ascites Meth A Sarcoma

The therapeutic effect of endogenous tumor necrosis factor (TNF) on Meth A ascites fibrosarcoma in mice was investigated. Serum and peritoneal fluid from tumor bearing mice treated with OK-432 and LPS were cytotoxic to tumor cells in vitro. The peak of cytotoxicity in both the serum and peritoneal fluid was found in the fraction corresponding to a molecular weight of approximately 54,000-56,000 on HPLC and the pI was found to be 4.9-5.1 by isoelectric focusing. These results are consistent with previously reported findings on TNF, and indicate that endogenous TNF has a satisfactory life-prolonging effect. The tumor necrosis factor (TNF) is considered to be one of the clinically most promising anti-cancer cytokines because of its potent and very specific antitumor effect on target cells (Carswell, Old, Kassel, Green, Fiore & Williamson, 1975; Matthews & Watkins, 1978; Niitsu, Watanabe & Urushizaki, 1984). TNF as an anti-cancer cytokine for the treatment of cancer may be applied in one of the two following ways: by administration of purified TNF or by endogenously inducing TNF in cancer bearing individuals. The antitumor effects of TNF administered exogenously have been examined using crude preparations or serum containing TNF (tumor necrosis serum, TNS) (Carswell et al., 1975; Watanabe, Niitsu, Sone, Neda, Ishigaki & Urushizaki, 1984). In a previous paper we reported that mice primed with OK-432 and challenged with endotoxin produced a soluble cytotoxic factor in peritoneal fluids (Yamamoto, Nagamuta, Usami, Sugawara, Watanabe, Niitsu & Urushizaki, 1985; Nagamuta, Yamamoto, Usami, Sugawara, Watanabe, Niitsu & Urushizaki, 1985). Ths peritoneal cytotoxic factor (PCF) had cytostatic and/or cytotoxic effect not only on mouse tumor cell lines but also on human tumor cell lines without species specificity. Normal cell lines were not affected. Here we report the endogenous production of TNF in tumor bearing mice and its antitumor effects.

Augmented systemic immunity in mice implanted with tumor necrosis factor-α, gene-transduced Meth-A cells

Syngeneic BALB/c mice bearing methylcholanthrene‐induced fibrosarcoma (Meth‐A) cells transduced with a tumor necrosis factor (TNF) gene showed a longer life span and tumor regression as compared with mice carrying TNF‐non‐producing Meth‐A cells. To elucidate the mechanism of the reduced tumorigenicity of TNF‐producing Meth‐A, we compared systemic immune responses between mice bearing high TNF producer (C5) and unmodified Meth‐A cells (M0). The results indicated that the cytotoxic activity of lymphokine‐activated killer cells (LAK) induced from spleen cells of mice bearing C5 was higher against both M0 and C5 than that of LAK from mice bearing M0. Also, C5 was more sensitive to LAK induced from spleen cells of C5‐ and M0‐ bearing mice than M0. We also found that cytotoxic T lymphocyte from spleen cells of mice transplanted with C5 was more cytotoxic to M0 than that from mice with M0. In addition, the population of Lyt2 (CD8)‐positive T cells was higher in freshly isolated spleen cells of mice transplanted with C5 than from mice with M0. Finally, we observed a higher expression of MHC class 1 antigen on C5 than on M0. These observations suggest that the augmented host systemic immunity in mice carrying TNF gene‐modified Meth‐A cells is one of the mechanisms of the reduced tumorigenicity of C5 and that the increased systemic immunity can be ascribed to the increased immunogenicity of the tumor cells. Thus, the use of TNF gene‐modified tumor cells as vaccines appears to be promising for therapeutic and/or prophylactic application.

Cell cycle specificity of tumor necrosis factor and its receptor

Phase specificity in the TNF cytotoxic effect and the number of TNF binding receptors was investigated using L-M cells incubated synchronously from the S phase. TNF cytotoxicity was observed to occur at various levels during the cell cycle, with peak effect in the G2-M phase. Analysis with 125I-labeled TNF to determine the number of receptors binding TNF in the various cell phases shewed a phase specificity with the maximum number occurring in the G2-M phase, similar to the peak in cytotoxicity. The results suggest the existence of a cell cycle specificity in the cytotoxicity of TNF which is apparently related to changes in the number of receptors capable of binding TNF.

Therapeutic Effect of Ok-432 Induced Endogenous Tnf on Tumor Bearing Mice and Cancer Patients

The therapeutic effect of OK-432 induced endogenous TNF on tumor bearing mice and cancer patients was investigated. OK-432 (10 KE/mouse) was administered intraperitoneally to Balb/c mice 7 days prior to the transplantation of Meth A cells (1 x 10(6)/mouse) into the abdominal cavity. And at day 1 of tumor inoculation, 1 KE/mouse of OK-432 was administered intraperitoneally. The significant prolongation of life span was observed in these mice. On the basis of these observation, therapeutic effect of endogenous TNF on cancer patients was clinically evaluated. OK-432 was administered intraperitoneally or intrapleurally to cancer patients with peritonitis carcinomatosa or pleuritis carcinomatosa 4 times (10KE each) every other day and 50KE of OK-432 was readministered with the interval of 7 days. An appreciable activity of TNF was detected in peritoneal fluids or pleural effusion, and the significant decreasing of these fluids was observed. It is therefore concluded that these therapeutic approach may well be taken into account in treatment of cancer.