We have previously utilized the myeloma cell line RPMI 8226 and its multidrug resistant 8226/Dox40 selleckchem Cisplatin subline for phenotype selective activity in response to an annotated compound library. The 8226/Dox40 subline over expresses P glycoprotein, but also other mechanisms are likely contributing to the multidrug resistant phenotype. We have also previously demon strated that over expression of STAT1 regulated genes con tribute to doxorubicin resistance observed in 8226/Dox40 cells. In the present study the same myeloma cell lines were tested in response to 3,000 chemically diverse compounds to explore the possibility of finding compounds selectively active against the MDR phenotype. After hit validation and counter screening one hit compound, VLX40, was selected for mechanistic investigation and further preclinical evaluation.

Methods Cell culture For primary screening RPMI 8226 and its multidrug resistant cell line 8226/Dox40 were used. In a secondary screen, a cell line panel representing different drug resist ance phenotypes was used. The cell lines of this panel were cultured and harvested Inhibitors,Modulators,Libraries as previously described. An additional 98 primary Inhibitors,Modulators,Libraries cultures of primary human tumor cells from different tumor types, and four preparations of normal peripheral blood mononuclear cells, detailed in Table 2, were used to determine the activity spectrum of VLX40 and, for comparison, six standard cytotoxic drugs chosen to represent different Inhibitors,Modulators,Libraries mechanistic classes. The tumor samples were obtained by bone marrow/peripheral blood sampling, routine surgery or diagnostic biopsy.

Leukemic cells and PBMCs were isolated by 1. 077 g/ml Ficoll Paque centrifugation. Tumor tissue from solid tumor samples was minced into Inhibitors,Modulators,Libraries small pieces and tumor cells were isolated by collagenase dispersion followed by Percoll density gradient centrifuga tion. The patient sampling was approved by the Regional Ethics Board, Uppsala, Sweden. Cell viability was determined by trypan blue exclusion test and the proportion of tumor cells in the preparation was judged by inspection of May Grunwald Giemsa stained cytospin slides. All samples used in this study contained more than 70% tumor cells. The human cell lines used for mechanistic studies were MCF7, HCT 116 and hTERT RPE 1. MCF7, HCT 116 and HL 60 were obtained Inhibitors,Modulators,Libraries from American Type Culture Collection whereas hTERT RPE 1 was from Clontech.

sellekchem In the in vivo hollow fiber studies the myelocytic cell line U 937 was used. The normal epithelial hTERT RPE 1 cells were cultured in Dulbeccos Modified Eagles Medium nutrient mixture F 12 Ham, supplemented with 10% heat inactivated fetal calf serum, 2 mM glutamine, 100 ug/ml streptomycin and 100 U/ml penicillin at 37 C in humidified air containing 5% CO2. MCF 7 was grown in in Eagles Minimal Essential Medium, supplemented as above. HCT116 were grown in complete McCoys medium.