In vitro growth inhibition of MM cells by NK4 protein. (A) MM cell lines (2 × 105 cells/mL) were cultured for 48 hours with the indicated concentrations of NK4 protein in RPMI containing 4% dialyzed FCS. Proliferation was evaluated by MTT assay. (B) Cells (2 × 105/mL) were cultured with the indicated concentrations of NK4 protein in RPMI containing 10% FCS. The number of cells was adjusted to 2 × 105/mL every passage. The number of live cells was counted every 5 days using the trypan blue exclusion test. (C) Antimyeloma effects of NK4 protein in combination with Dex treatment. NK4 protein was added to the culture medium in the presence of Dex. KMS11 is a Dex-sensitive MM line, and KMS34 is a Dex-resistant line. Proliferation was evaluated by MTT assay as described. (D) Primary MM cells obtained from the patients were cultured for 48 hours with various concentrations of NK4 or HGF (or both) in RPMI containing 4% dialyzed FCS, and an MTT assay was conducted. For all studies in panels A-D, the mean ± one SD, each in triplicate, is shown.
