Prediction of drug cytotoxicity in 9L rat brain tumor by using flow cytometry with a deoxyribonucleic acid-binding dye.
OBJECTIVE
Flow cytometry (FCM) with a deoxyribonucleic acid (DNA)-binding dye, propidium iodide, provides a rapid and quantitative method to detect apoptotic cell death. This technique was used to examine the sensitivity of tumor cells to anticancer agents, as a novel test of chemosensitivity in vitro.


METHODS
The in vitro chemosensitivity of 9L gliosarcoma cells to a panel of anticancer agents (cisplatin, nimustine, adriamycin, cyclophosphamide, vincristine, 5-fluorouracil, and methotrexate) was investigated by both FCM, yielding DNA histograms, and a microtiter tetrazolium test, measuring cellular metabolism. Clinically achievable concentrations of the agents were used for the analysis of DNA histograms and proliferation of 9L cells in vitro. Rats intracranially inoculated with 9L cells were treated with the agents, and tumor masses were visually monitored by using magnetic resonance imaging with gadolinium-diethylenetriaminepentaacetic acid enhancement.


RESULTS
The cytotoxic effect of anticancer agents examined by the microtiter tetrazolium test correlated with a decreased G0/G1 peak in the DNA histograms. Serial FCM analysis showed that the decrease in the G0/G1 peak was subsequently accompanied by increased hypodiploid areas, suggesting DNA fragmentation induced by the agents. The in vitro chemosensitivity test and cell proliferation examination showed that all agents except cisplatin were effective. Growth retardation of inoculated brain tumors and prolonged survival of inoculated rats were observed with treatment with the anticancer agents, except cisplatin.


CONCLUSIONS
The present study shows that FCM analysis with a DNA-binding dye can detect DNA damage induced by anticancer agents, and it suggests that this technique is a novel method to test chemosensitivity in vitro.
Iwadate
Y
Y
Department of Neurosurgery, Chiba University, Japan.
Fujimoto
S
S
Sueyoshi
K
K
Namba
H
H
Tagawa
M
M
Yamaura
A
A
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D001932:Brain Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis*; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D005434:Flow Cytometry / Q000379:methods*; D005456:Fluorescent Dyes; D018316:Gliosarcoma / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009368:Neoplasm Transplantation; D011419:Propidium; D051381:Rats; D011916:Rats, Inbred F344
D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D005456:Fluorescent Dyes; D011419:Propidium