Fig 5.

(A) A collection of different human multiple myeloma cell lines are Activin A-resistant. Ten different cell lines were incubated with or without 125 nM Activin A. After 72 h, cell proliferation was assessed by WST-1 measurements. (B) Expression profile of Activin A receptors in MM cell lines. RNA was isolated from the indicated MM cell lines, and the expression levels of the indicated receptors were determined by qRT-PCR. Expression levels were normalized to the housekeeping gene HPRT (= 100%). (C) Activin A sensitivity of primary CD138+ cells isolated from different MM patients. CD138+ cells were isolated from 8 different donors and stimulated with 125 nM Activin A for 72 h. The control cells were untreated. Cell numbers were assessed by WST-1 assay and related to the untreated cells (control). Assays were performed in duplicate (except for the values marked with a #). The figures show the mean values and standard deviation of duplicates.