Chemosensitivity and multidrug resistance to antineoplastic drugs in retinoblastoma cell lines

Abstract

Chemosensivity testing in 11 retinoblastoma (RB) cell lines identified five tumors showing cross-resistance to plant alkaloids, alkylating agents, anthracycline antibiotics, and antimetabolites, suggestive of the multidrug-resistant (MDR) phenotype described in other tumors. Only two tumors had been clinically exposed to chemotherapy, and both showed MDR. All RB tumors were resistant to clinically achievable concentrations of methotrexate and hydrocortisone, and only sensitive to cytosine arabinoside. These results provide a rational basis on which to develop new chemotherapeutic strategies for the treatment of RB.