Figure 1
(R,S′)-MNF inhibits proliferation of PDAC cell lines. (A) (R,S′)-MNF (structure depicted) treatment reduces PANC-1 cell proliferation. [3H]-Thymidine incorporation into PANC-1 cells was assessed after incubation with increasing concentrations of (R,S′)-MNF for 24 h. Data are expressed as mean ± SD from 3 independent experiments. The calculated IC50 value was 0.11 ± 0.08 µM. (B) PDAC cell lines were exposed to (R,S′)-MNF for 72 h. Next, the viability of the cells was assessed using the Sulforhodamine B (SRB) assay. (R,S′)-MNF inhibited the survival of the MIA PaCa-2, PSN-1, PANC-1, HPAC, and Capan-1 cells with the IC50 of 5.2, 8.3, 9.6, 5.0, and 6.8 µM, respectively. (C) Upper panel, Immunoblot showing levels of phosphoactive and total forms of ERK after a 20-min pretreatment of serum-depleted PANC-1 cells with or without 1 µM (R,S′)-MNF followed by short term incubation with the GPR55 agonist O-1602 (10 µM, 20 min). Lower panel, Protein bands were quantified by densitometry, and the ratio of phosphorylated/total forms of ERK1/2 was calculated and plotted relative to O-1602-treated cells. Values are represented as boxplots with n = 6. Data analysis: one-way ANOVA followed by Tukey’s post-hoc test; **, ***P < 0.01, 0.001 vs. control or vs. marked treatments. All graphs were generated with GraphPad Prism v.8.4.3 (GraphPad Software, Inc., La Jolla, CA).
