A Model of the Development of Cisplatin Resistance in Human Small Cell Lung Cancer Xenografts

Background/Aim: To study the prevention of chemotherapy resistance, we have previously designed models of drug-resistant ovarian cancer. We here report an in vivo model of cisplatin-resistant small cell lung cancer (SCLC). Materials and Methods: Mice bearing H526 SCLC xenografts received intraperitoneal pretreatment with a sub-effective cisplatin dose (0.75-1.5 mg/kg) or no pretreatment (controls). Seven days later, all mice received a higher cisplatin dose (3.0 mg/kg), and tumor response was recorded. Cell cultures initiated from pretreated and control xenografts were tested for cisplatin resistance and for glutathione-S-transferase (GST) activity. Results: Pretreatment with 1.5 mg/kg cisplatin induced resistance to 3.0 mg/kg cisplatin. Cells from a pretreated tumor were cisplatin resistant and had nearly twice the GST activity as cells from a control tumor. Conclusion: Such cells may prove useful for identifying other resistance mechanisms and thus guide the selection of potential preventative agents to be tested in the in vivo model.