Multiple myeloma is a clonal plasma cell malignancy that accounts for 10% of all haematological cancers. Complex interactions of the cancer cells with the bone marrow microenvironment, including activation of osteoclasts and suppression of osteoblasts, lead to lytic bone disease. Heterogeneity of the myeloma contributes to the rapid emergence of drug resistance in high-risk disease. Despite of recent therapeutic advances, myeloma is widely considered as an incurable disease. The responses to treatments depend on the patient and the type of myeloma, and it is therefore of importance to know the direct response to treatment of cancer cells. We have optimised in vitro cell viability and apoptosis assays for identifying compounds that affect human multiple myeloma and plasma cell leukemia. LP-1, MOLP-8, RPMI-8226 and OPM-2 human multiple myeloma cells and JJN-3 and L-363 human plasma cell leukemia cells were used in the study. The anthracycline antibiotic doxorubicin was tested as a reference compound with the range of 1 nM to 1 μM concentrations. The cells were cultured for 5 days and the effects of doxorubicin were identified by measuring proliferation of the cells at days 1, 3 and 5 using CellTiter-Glo viability assay. Effects on apoptosis were assessed at day 1 by measuring caspase 3/7 activity using Caspase-Glo 3/7 assay. Doxorubicin showed potent inhibition of cell proliferation at 10 nM concentration in RPMI-8226 and MOLP-8 cells and at 100 nM concentration in all other cell lines tested. There were no major differences of treatment responses to apoptosis induction between the cell lines, with the exception that doxorubicin was more potent to MOLP-8 cells than to the other cells. We conclude that this culture system can be used as a screening tool for finding new chemotherapy agents on multiple myeloma and plasma cell leukaemia.
Disclosure: Katja Fagerlund, Jani Seppänen, Mari Suominen, Jukka Rissanen, Jenni Bernoulli, and Jussi Halleen are employees of Pharmatest Services Ltd. Ningshu Liu and Arne Scholz are employees of Bayer Pharma AG.