Koichi Ishikura

INHIBITION OF TUMOR GROWTH AND ANGIOGENESIS BY VITAMIN D3 AGENTS IN MURINE RENAL CELL CARCINOMA

PURPOSE To investigate the effect of active vitamin D3(VD) agents on tumor growth and metastasis. MATERIALS AND METHODS BALB/c mice were inoculated with murine renal cancer Renca and graded doses of 1,25-dehydrovitamin D3 or 1- hydrovitamin D3 were given intraperitoneally every other day beginning on day 1, 3, or 7 and ending on day 9, 11, or 15. Direct cytocidal activity and angiogenic activity were evaluated by 48-hour MTT assay and by the colorimetric method, respectively. RESULTS Both VD agents inhibited tumor growth and prolonged the life span of Renca-bearing mice in a dose-dependent manner and both suppressed tumor growth in athymic mice and euthymic mice with eliminated NK activity. Marginal body-weight loss without appreciable hypercalcemia was observed in mice given VD agents. When treatment was delayed on day 7, the VD agents failed to inhibit tumor growth. The MTT assay showed no direct cytotoxicity of VD agents on Renca. Tumor angiogenesis was inhibited to 46 to 30% of the control level by VD agents. Furthermore, VD agents reduced pulmonary and hepatic foci in the metastatic models. CONCLUSIONS These results suggest that VD agents may be effective as a treatment for renal cell carcinoma, especially when micrometastases are involved.

Interleukin-2 Expanded Tumor-Infiltrating Lymphocytes and their Response to Preoperative α-Interferon in Patients with Renal Cell Carcinoma

To determine whether interferon-alpha could augment antitumorigenic effect of the tumor-infiltrating lymphocytes expanded with interleukin-2, we evaluated the properties of interleukin-2 expanded tumor-infiltrating lymphocytes in 24 patients with renal cell carcinoma with or without treatment with interferon-alpha. Tumor-infiltrating lymphocytes containing tumor cells were separated from nephrectomy specimens by enzymatic digestion and Percoll gradient centrifugation, and were cultured in the serum-free medium containing interleukin-2. The number of lymphocytes increased by 10 to 1,000-fold by day 28 of culture. There was no difference in the proliferation of tumor-infiltrating lymphocytes between interferon-alpha treated patients and controls. On day 14 tumor-infiltrating lymphocytes in the treated patients contained significantly more activated cells (HLA-DR+) and suppressor T cells (CD8+11+) than those in the controls. No significant difference was noted, however, in the cytotoxicity of tumor-infiltrating lymphocytes against autologous and allogenic renal cell carcinoma, K-562 or Daudi cells between the experimental and control groups on day 14 or 28. No specific effects on the major histocompatibility antigens, such as modulation of the expression attributable to the preoperative treatment with interferon-alpha, were observed on renal cell carcinoma tissue when determined by immunohistochemical staining. These findings suggest that interferon-alpha does not consistently produce a beneficial effect on interleukin-2 expanded tumor-infiltrating lymphocytes in patients with renal cell carcinoma.

Combined effects of intraperitoneal administration of recombinant interleukin-2 and streptococcal preparation OK-432 in murine tumors.

The combined effects of rIL-2 and OK-432 were investigated against a Meth-A tumor, a syngeneic tumor of inbred BALB/c mice. An analysis of the effector cells was also performed. The treatment resulted in an inhibition in vivo of tumor growth and increased survival of the Meth-A tumor-bearing mice. Splenic cells obtained from Meth-A inoculated mice which received combination therapy were not only NK-sensitive YAC-1 and LAK-sensitive EL-4 cells, but also NK-resistant Meth-A cells, as shown in a 4-h 51Cr-release assay. Syngeneic killer cell activity against Meth-A cells was abolished almost completely with anti-Thy 1.2 treatment and about 70% of the activity was abolished with anti-asialo GM1 treatment in a complement-dependent cytotoxic assay. It was not changed by the removal of macrophages and B cells from the splenic cells. Mice which survived for 60 days after the start of therapy rejected Meth-A inoculation when rechallenged, suggesting the establishment of a specific immunity. Combination therapy appeared to be beneficial against Meth-A cells and T-cells appeared to play a determining role in the treated Meth-A bearing mice. It was suggested that more than two populations of killer cells exist in the spleen treated with the combined therapy and they may have the same characteristics as activated T and NK cells with or without specific killer T-cells.