Fig. 1

Monoamine oxidase-A expression increases at the transcript and protein level in human breast tumor cells propagated as tumorspheres. a Log2 normalized MAO-A transcript counts from Nanostring nCounter analysis of total RNA isolated from human breast tumor cell lines grown adherently (A) or as tumorspheres (S). Human brain RNA was included as a positive control. b Log2 normalized MAO-A expression from microarray analysis of primary patient tumor cells propagated as tumorspheres [FC = 4.80; p = 5.30E-05]. c Western blot analysis of 6 human breast tumor cell lines grown adherently (A) or as tumorspheres (S) with a primary antibody that binds to MAO-A at its approximated molecular weight of 61 kDa. An α-tubulin loading control was included. Lanes were cropped from 3 separate blots as described in Additional file 5. d RNA sequencing data from 60 breast tumor cell lines was downloaded from Array Express [E-MTAB-2706]. Transcript abundance (transcripts per million; TPM) was plotted for each cell line. The green bars indicate cell lines that expressed MAO-A at a 50-fold higher level than the median TPM of all samples (black dotted line)