ABSTRACT
INTRODUCTION: Our goal was to establish versatile and high capacity assays to characterize activity and toxicity of chemotherapeutics. The major anti-cancer activity indicators of these agents included inhibition of proliferation and induction of apoptosis to cancer cells. In addition, cytotoxicity and myelosuppressive activity to normal cells were parameters to evaluate toxicity of these drugs. METHODS: Using a panel of cell-based assay systems, we investigated activity and toxicity properties of selected cancer drugs. Drug effects on a number of normal and cancer cell types from human origin were evaluated. RESULTS: Topoisomerase inhibitors (camptothecin, doxorubicin and etoposide) and microtubule inhibitors (colchicine and paclitaxel) showed anti-proliferation activity and induced apoptosis in MDA-231 cancer cells. Except for doxorubicin, these drugs had relatively low toxicity to normal cells because the dosage required for cytotoxicity EC(50) was >200-folds higher than the dosage for anti-proliferation EC(50) in cancer cells (MDA-231, HL60). However, these drugs were potent inducers of myelotoxicity in human bone marrow progenitor cells. In comparison, the DNA alkylating agents (cisplatin and carboplatin) were less potent proliferation inhibitors (EC(50)>10 microM) in MDA-231 cells and they were also less myelosuppressive. DISCUSSION: Using marketed drugs as examples, our study established a multiple assay platform for profiling in vitro properties of cancer drugs. In drug discovery, such a platform will help to expedite lead selection at early stage.
Subject(s)
Antineoplastic Agents/pharmacology , Antineoplastic Agents/toxicity , Drug Evaluation, Preclinical/methods , Animal Testing Alternatives , Apoptosis/drug effects , Breast/cytology , Caspase 3/metabolism , Caspase 7/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Cells, Cultured , Epithelial Cells , Hematopoietic Stem Cells/drug effects , HumansABSTRACT
Chemo-therapeutic drugs act on cancerous and normal cells non-selectively and often cause organ impairments during treatment. Improving safety or reducing toxicity becomes an important challenge for developing better anticancer drugs. In the present study, effects of selected anticancer drugs (camptothecin, doxorubicin, colchicine, paclitaxel, cisplatin, and carboplatin) on cell viability and proliferation was investigated. The anti-proliferative activity of each drug on cancer cells (human hepatoma HepG2) and human primary renal proximal tubule cells (hRPTECs and LLC-PK1) was determined with the [(3)H]thymidine incorporation assay. Results indicated all six drugs blocked cell proliferation in cancer and normal cells. When the anti-proliferation potency was ranked in hRPTECs based on EC50 values, camptothecin is the most potent, followed by doxorubicin, paclitaxel, colchicine, cisplatin and carboplatin. Cytotoxicity of drugs to hRPTECs was assessed with the ATP bioluminescence assay. Doxorubicin and cisplatin were known to induce nephrotoxicity in vivo and they were indeed cytotoxic to hRPTECs in our study with EC50 values at 11.2 and 39.6 microM. All other drugs are not cytotoxic in the concentrations tested. These drugs typically displayed separation of EC50s between potency (anti-proliferation) and cytotoxicity. The dose separation provides a concentration range for each drug to act on cell proliferation without induction of significant cytotoxicity. Our results suggest that hRPTEC system can serve as an in vitro model for assessing potential nephrotoxicity of chemo-therapeutic drugs.
