Yuka Matsushima

Time-schedule dependency of the inhibiting activity of various anticancer drugs in the clonogenic assay

SummaryTo analyze the discrepancy between the in vitro response in the clonogenic assay and the clinical response, the time-schedule dependencies of various anticancer drugs were determined by comparing the inhibiting effect against colony formation by PC-7 cells treated with the drugs for 1 h with that of those treated for 24h. According to their schedule dependency the drugs can be divided into a schedule-dependent drug group (5-fluorouracil, methotrexate, bleomycin, pepleomycin, etoposide, cisplatin, teniposide, vindesine, and vinblastine) and a non-schedule-dependent drug group (adriamycin, actinomycin D, ranomustine, mitomycin C, aclacinomycin, daunomycin, nimustine, melphalan, and KW 2083). In the clonogenic assay, the 1-h exposure schedule is appropriate for predicting clinical response for the non-schedule-dependent drugs. However, the effect of the schedule-dependent drugs was underestimated in the same conditions. Therefore, it is necessary to test these drugs in the assay by 24-h exposure for a more accurate assessment of their antitumor activity.

In vitro antitumor effect of recombinant human tumor necrotizing factor on cultured human cancer cell lines and freshly isolated lung cancer cells by the human tumor clonogenic assay

SummaryIn vitro antitumor effects of human recombinant tumor necrotizing factor (rH-TNF) were examined against nine lung cancer cell lines including six non small and three small cell lung cancer, four stomach cancer cell lines and 30 freshly isolated lung cancer cell samples by the human tumor clonogenic assay. rH-TNF did not show any inhibitory effect on the colony formations of lung and stomach cancer cell lines, except for PC10 established from squamous cell carcinoma even at the high concentration. The overall response rate of fresh material was 11.5%. The colony formations of only two materials from 20 patients without prior chemotherapy were significantly suppressed by rH-TNF in vitro. Three specimens of adenocarcinoma exhibited more than 70% decrease in colony number by treating with 100 and 1000 u/ml of rH-TNF resulting in the response rate of 15.8% (3/19). From these results, it can be concluded that rH-TNF has modest direct cytotoxic effect on lung cancer, and additional study against adenocarcinoma of the lung might be warranted.

Human Tumor Clonogenic Assay for Carcinoma of the Lung

The human tumor clonogenic assay (HTCA) has potential value for studies of both the chemosensitivity and biology of human tumors. However, many technical problems including low plating efficiencies and the preparation of sufficient numbers of viable cells remain. In this study, an improved method for disaggregation of solid tumors increased the yield of single cells. Consequently, more than 10 anticancer drugs could be tested in 94 of 168 specimens (56%). Removal of peripheral blood lymphocytes from cell suspensions derived from effusions also improved colony formation. Adequate growth for sensitivity testing (greater than 30 colonies/plate) was obtained in 122 cases (73%), inadequate growth for drug evaluation (5-29 colonies/plate) in 29 cases (17%), and no colony formation (less than 5 colonies/plate) in 17 cases (10%) of the 168 viable samples. The cloning efficiencies of cells derived from primary tumors (median 0.015%) were higher than those of cells derived from metastatic tumors (0.012%), and they varied with the location of the metastatic site. Cloning efficiencies varied markedly from specimen to specimen, and were unaffected by tumor histology, grade of differentiation, patient age, stage of disease, or prior chemotherapy. The HTCA is promising as a potential tool for studying the biology of tumors.

Evaluation of a new drug 7-N-(p-hydroxyphenyl)-mitomycin C [KW 2083] against carcinoma of the lung by the human tumor clonogenic assay.

SummaryKW 2083, which is a new mitomycin C derivative currently under clinical investigation, was tested for its antitumor effect on the growth of human carcinoma of the lung by using an in vitro clonogenic assay system. The in vitro results in this study were as follows: 1) We succeeded in producing clonal growth at a high rate in all histologic types of carcinoma of the lung in the assay system. That is, 61 of 81 specimens (75%) of either primary or metastatic tumors gave adequate growth for chemosensitivity testing. The in vitro responses to vindesine, adriamycin, mitomycin C and melphalan (substituted for cyclophosphamide in vitro), as standard anticancer drugs for chemotherapy of carcinoma of the lung were 18, 23, 18 and 19%, respectively, which are in good general agreement with the clinical responses to these drugs reported previously. Therefore, the clonogenic assay system might prove to be a very effective tool for an in vitro phase II study of new drugs. 2) The rate of response to KW 2083 tested simultaneously in 51 cancer specimens was 22%, which was superior to that of mitomycin C. These results indicate that KW 2083 might be more useful than mitomycin C in clinical practice.

A new antitumor antibiotic FR66973: clonogenic in vitro assessment of activity against human non-small cell lung carcinoma.

SummaryWe have utilized a human tumor clonogenic assay (HTCA), as a disease-oriented drug screening model of new antitumor drugs, to test the antitumor activity of FR66973 and compared the activity with that of its analogous compound, mitomycin C. The overall in vitro response rate (defined as less than 50% survival of tumor colony forming units) for FR66973 against fresh tumor cells obtained from patients with non-small cell lung carcinoma (NSCLC) was 32%, 50% and 89% at 0.1, 1 and 10 μg/ml, respectively, which was superior to that of mitomycin C at the corresponding concentration. Our data suggest that FR66973 is a promising new drug against NSCLC. If phase I toxicities are not prohibitive, FR66973 may also have good activity against NSCLC in clinical phase II trial.