Figure 1.

(A) MTT analysis of Calu6, Calu6cisR1-3, H23, and H23cisR1-3 following 48-hour treatments with cisplatin, carboplatin, and doxorubicin. Cisplatin and carboplatin treatments showed reduced cytotoxicity in the Calu6cisR1-3 and H23cisR1 compared to their parental cell lines. With the exception of Calu6cisR3, response to doxorubicin treatment was similar in the parental and cisR1 sublines. *Significant difference in the viability curves of the cisR sublines compared to their parental counterparts (P< .05). (B) No significant morphological differences were observed between the parental and resistant sublines (phase microscopy); however, proliferation rates as determined by cell doubling times were reduced in the Calu6cisR sublines, and this was most pronounced in the Calu6cisR3 cell line.