Combined chemotherapy and ALA-based photodynamic therapy in leukemic murine cells.

The effects of combined administration of doxorubicin (DOX) and vincristine (VCR), with 5-aminolevulinic acid photodynamic treatment (ALA-PDT), were analyzed in sensitive murine leukemic cell lines (LBR-) and DOX and VCR chemoresistant LBR-D160 and LBR-V160 cell lines. Low doses of DOX and VCR increased anti-cancer effect of ALA-PDT in LBR-cells. Decrease in cell survival was higher when the combination VCR+ALA-PDT was used compared to DOX+ALA-PDT. Resistant cell lines LBR-D160 and LBR-V160 were sensitive to ALA-PDT; however, no changes occured when combining therapies. Thus, ALA-PDT can overcome drug resistance and is a good candidate for using treating multidrug resistant (MDR) cells.