Sensitization and apoptosis augmentation of K562/ADM cells by anti-multidrug resistance gene peptide nucleic acid and antisense oligodeoxyribonucleotide.

Aim: To investigate the reversal effect and apoptosis enhancement of peptide nucleic acid (PNA) and antisense oligodeoxyribonucleotide (ASODN) targeted to multidrug resistance gene (mdr1) on human multidrug resistant leukemia K562/ADM cells.

Methods: A 15-mer PNA and the same sequence of ASODN, complementary to the 5' end of the AUG initiator codon-containing region of mdr1 messenger RNA (MDR1-PNA, MDR1-ASODN), were designed and synthesized. Proliferation and sensitivity to adriamycin of K562/ADM cells treated with MDR1-PNA- and MDR1-ASODN were analyzed with a MTT colorimetric assay.

[Arsenic trioxide inhibits P-glycoprotein expression in multidrug-resistant human leukemia K562/ADM cell line that overexpresses mdr-1 gene and enhances their chemotherapeutic sensitivity].

Objective: To investigate the effects of arsenic trioxide (As(2)O(3)) on the apoptosis and P-glyco-protein (P-gp) expression of multidrug-resistant human leukemia K562/ADM cells, and the combined effects of As(2)O(3) with conventional chemotherapeutic agents.

Methods: Multidrug-resistant human leukemia cell line K562/ADM that overexpresses mdr-1 gene was used as the target cells. The cell proliferating activity was assessed with a MTT assay.