['To investigate the effect of overexpression of S3 ribosomal protein (S3rp) gene on the resistance of leukemia cell to antitumor drugs.', 'Both sense and antisense cDNA recombinants of S3rp gene were constructed with pcDNA3.1 expression vector. Subsequently, the sense S3rp cDNA recombinant was transfected into K562 cells while the antisense one into K562/DOX cells (a multidrug resistant cell line). In addition, empty pcDNA3.1 vector was transfected into the corresponding cells as negative controls. The chemosensitivity of cells was evaluated by MTT assay.', 'Sense S3rp cDNA transfected K562 cells were 5.8 times more resistant to doxorubicin than control cells did, whereas antisense S3rp cDNA transfected K562/DOX cells were 3.2 times less resistant to doxorubicin than control cells did.'] Is [ Overexpression of S3 ribosomal protein gene involved in drug resistance in K562/DOX cells ]?