Objective: To determine the apoptotic effects of different chemotherapeutic agents on the retinoblastoma(RB) cell line HXO-RB44 and to establish a drug-induced apoptosis model of RB in vitro as the basis for further research on the mechanism of drug-induced apoptosis and spontaneous regression of RB.
Methods: Twelve chemotherapeutic agents, including vincristine, cytarabin, methotrexate, cyclophosphamide, thiotepa, mitoxantrone, aclanomycin, pirarubicin, cisplatin, carboplatin, mitomycin, etoposide, of different concentration (10(-9), 10(-8), 10(-7), 10(-6), 10(-5), 10(-4) mol.L-1) were employed into HXO-RB44 cell line respectively for 24 hours, then apoptotic effects on it were decided by observing the DNA ladders on agarose gel electrophoresis. After that, one chemotherapeutic agent with the most evident DNA ladders was applied into HXO-RB44 cell line for 4, 8, 16, 24, 48 and 72 hours respectively, and the DNA ladders on agarose gel were also surveyed. Apoptotic cells were identified with transmission electron microscopy.
Results: Typical DNA ladders were shown on agarose gel after HXO-RB44 cell line were exposed to 10(-6)-10(-5) mol.L-1 vincristine and 10(-5) mol.L-1 aclanomycin for 24 hours and the former were much clearer. No DNA ladders did emerge when the RB cells were treated by the rest ten chemotherapeutic agents. The DNA ladders began to appear when dealt with 10(-5) mol.L-1 vincristine for 8 hours, to be most obvious for 24 hours, and abated for 48 hours then disappeared for 72 hours. Amount of apoptotic RB cells were observed by transmission electron microscopy.
Conclusion: Both vincristine and aclanomycin have the effect of inducing apoptosis on HXO-RB44 cell line, but that of vincristine is more forceful, which is time and concentration dependent. So vincritine is an ideal agent for establishing an apoptosis model of HXO-RB44 cell line.