The combination effects of CDDP and hyperthermia in mouse bladder tumor (MBT-2) were investigated both in vivo and in vitro. MBT-2 was transplanted into the hind leg of a C3H/He mouse. Then the leg was dipped in a hot water bath immediately after the intraperitoneal administration of CDDP. The antitumor effects were evaluated from tumor volume. The CDDP plus hyperthermia (43 degrees C) group showed remarkable tumor growth retardation. The in vitro colony forming assay showed that MBT-2 cultured cells treated with CDDP at 42 degrees C exhibited great colony forming inhibition in comparison with the CDDP alone cells. The effects of CDDP plus hyperthermia on the cell cycle progression of MBT-2 cultured cells were studied by using flow cytometry. The results showed that the cells treated with CDDP at 42 degrees C exhibited an accumulation of cells in the C2 phase for many hours as compared with the CDDP alone cells, indicating thermal enhancement of DNA damage in MBT-2 cultured cells treated with CDDP.

Eighteen patients in a high-blast group of myelodysplastic syndrome were treated with low-dose SM-108 (4-carbamoylimidazolium 5-olate). Seven of the 18 patients (38.9%) achieved a partial response, and 4 (22.2%) achieved complete response. Treatment was associated with significant, but transient myelotoxicity. Changes in CFU-GEMM clonal growth were examined in bone marrow from patients during the treatment.

The use of medroxyprogesterone acetate (MPA) in therapy of patients with endometrial cancer has been recently examined by the Japan Gynecological Cancer Treatment Group. The response rate of oral MPA was 23.6% (13/55 evaluables) and the average period up to the onset of response was 15.2 weeks (4-28 wks). The response rate was higher in well-differentiated tumors than in poorly differentiated ones. Although it is well known that steroid hormone action is mediated by steroid hormone receptor, the presence of progesterone receptor in cancer tissue seems to be not absolutely necessary for the responsibility to MPA, a potent progestational compound. The reason was studied, in vitro, in our laboratory by using the technique of human tumor clonogenic assay. In this system, MPA showed a marked suppressive effect on the colony formation of endometrial cancer cells. Similar effects were also observed with progesterone, 17 alpha-hydroxyprogesterone caproate and megestrol acetate. Norethindrone and norgestrel, which are both potent progestational compounds, showed almost no anticancer activity on Ishikawa cell in this in vitro system. It became clear that progestational activity was not always associated with anticancer activity, and norethindrone had no influence on the inhibitory effect of MPA, although norethindrone has a strong affinity for progesterone receptor. Similarly, RU 486, which is known as a potent antiprogestogen agent and has a high affinity to progesterone receptor, did not influence the effect of MPA. These results clearly indicated that the anticancer activity of MPA was not mediated by high affinity low capacity progesterone receptor, and a pharmacological effect must be considered for understanding the effect of MPA on endometrial cancer.

We have collected peripheral blood mononuclear cells in large quantities by leukapheresis from children with malignant disorders. The cells were fractionated on discontinuous gradients of Percoll for enrichment of hematopoietic stem cells and reduction of sample volume. They were subsequently frozen in a programmed freezer and stored in liquid nitrogen. This procedure allows a reduced DMSO volume to be infused into patients and increases storage space. The recovery rates of progenitors evaluated by freeze-thaw analysis in small aliquots were 89% for granulocyte-macrophage colony-forming units (CFU-GM) and 106% for granulocyte, erythroid, macrophage, megakaryocyte colony-forming units (CFU-GEMM). Hence, we conclude that circulating stem cells can be collected and cryopreserved in large quantities without any loss of capacity. Further studies to evaluate the relevance of performing rescue surgery with these stem cells following marrow-ablative chemotherapy are underway.

Circulating hematopoietic stem cells were collected by three consecutive leukaphereses during post-chemotherapy expansion of the stem cell pool in a 3-year-old boy with advanced and therapy-resistant neuroblastoma. The cells were fractionated by discontinuous Percoll gradient centrifugation, frozen in a programmed freezer and then stored in liquid nitrogen. Following high-dose chemotherapy, the cells were thawed rapidly and re-infused into the patient. Early evidence of marrow recovery was first noted at day 13 and the times required to achieve a granulocyte count of greater than 0.5 x 10(9)/L and a platelet count of greater than 50 x 10(9)/L were 21 days and 30 days, respectively. This new marrow-rescue operation may have potential in cancer therapy as an alternative to bone marrow transplantation and further clinical investigation is warranted.

Four human lung small cell carcinoma (SCC) cell lines were used for the experimental cancer chemotherapy with a single agent and combination method. The chemosensitivity of SCC cell lines including H-69, H-128, Lu-24 and Lu-134 were assessed by the clonogenic assay according to the method of Salmon and Humburger. Cyclophosphamide (CPA) showed the most excellent antitumor effect against these 4 strains followed by tetra-hydropyranyl adriamycin and adriamycin (ADM). In vitro combination clonogenic assay was conducted by mixing the half of the concentration of two matched drugs and the synergistic effect was evaluated according to the method of Berenbaum. Whereas the synergistic effects were frequently observed in the combination of drugs which were effective by the single usage, it was found that the combination of CPA + mitomycin C and CPA + ADM showed high efficacy rates against these cell lines in comparison with other matchings. From these findings, it was concluded that the combination chemosensitivity test in clonogenic assay might be a promising method to evaluate the chemosensitivity of the individual patient. And it was supposed that this method might be also useful as an early phase III study to predict the useful combination of newly developed antitumor agents.

The antitumor activities of several chemotherapeutic agents were tested in the human tumor clonogenic assay (HTCA) and in subrenal capsule assay (SRCA). The results obtained in these two assays and clinical response were compared. 1. Colony growth was observed in 43 of 73 tumors (58.9%), and the adequate colony growth to evaluate the response of therapeutic groups was obtained in 21 tumors (28.8%). 2. Control growth adequate to meet evaluable assay criteria was obtained in 38 of 43 tumors (88.4%). 3. With activity criteria set at a decrease of greater than or equal to 50% in tumor colony-forming units for the HTCA and a change in tumor size less than or equal to -1.0 dmm for the SRCA, 24 of 98 drugs tested were active in HTCA (24.5%), and 50 of 160 drugs were active in SRCA (31.2%). 4. A total of 21 tumors was tested in both HTCA and SRCA and the tumor response was compared in 12 tumors treated with 39 drugs. Correlation of tumor responses between the two assays was 71.8%. 5. A total of 8 HTCA-clinical correlations and 5 SRCA-clinical correlations were possible. Overall predictive accuracy was 87.5% in the HTCA and 80.0% in the SRCA, respectively.