Fig. 1: 27HC inhibits the growth of ER-negative breast cancer cells.

a ER-positive MCF7 cells were plated in charcoal stripped serum (CFS, left) and complete (FBS, right) media, followed by treatment with the indicated doses of 27HC. Cells were then harvested at different time points and cell growth was assessed by measuring DNA content using Hoechst 33258. b MCF7 cells were seeded in 6-well plates in soft agar mixed with media containing stripped (CFS, left) and complete serum (FBS, right), followed by the treatment with vehicle (0.1% DMSO) or 27HC (1 µM), and incubated for 3 weeks. Colonies were stained with crystal violet. The graph represents the number of colonies growing in soft agar per well. c Time-dependent cell growth curves of various ER-negative breast cancer cells (4T1, Met1, MDAMB436, MDAMB231, Py230, and HCC1954) treated with indicated concentrations of 27HC. d Soft agar assay showing that 27HC (1 µM) inhibits the colony formation of 4T1 and Met1. e qRT-PCR analysis of the mRNA expression levels of LXR, SREBP1c, and SREBP2 (genes involved in lipid metabolism) from 4T1, Met1, MDAMB436, HCC1954, and Py230 cells treated with 27HC (5 µM) for 24–72 h. f Supplementation with cholesterol (Chol, 10 µM) but not mevalonate (MVA, 500 µM) reversed the antiproliferative effects of 27HC (5 µM) in 4T1, MDAMB436, HCC1954, and Py230 cells. Data are plotted as mean ± SEM as representative results from two to four independent experiments (except Fig. 1b which was performed a single time); n = 5 wells of cells (a, c, and f); n = 3 wells of cells b and d; n = 4 wells of cells e. P values were calculated using two-sided unpaired Student’s t test b, d, and e. Numerical source data are reported in the Supplementary Data 1 and in the Source Data File.