dorsomorphin and versipelostatin

Inhibiting the unfolded protein response (UPR) can be a therapeutic approach, especially for targeting the tumor microenvironment. Here, we show that compound C (also known as dorsomorphin), a small-molecule inhibitor of AMP-activated protein kinase (AMPK) and bone morphogenetic protein (BMP) signaling, inhibit the UPR-induced transcription program depending on the glucose deprivation conditions. We found that compound C prevented UPR marker glucose-regulated protein 78 (GRP78) accumulation and exerted enhanced cytotoxicity during glucose deprivation. Gene expression profiling, together with biochemical analysis, revealed that compound C had a unique mode of action to suppress the transcriptional activation of UPR-targeted genes, as compared with the classic UPR inhibitors versipelostatin and biguanides. Surprisingly, the UPR-inhibiting activity of compound C was not associated with either AMPK or BMP signaling inhibition. We further found that combination treatments of compound C and the classic UPR inhibitors resulted in synergistic cell death with UPR suppression during glucose deprivation. Our findings demonstrate that compound C could be a unique tool for developing a UPR-targeted antitumor therapy.

Topics: Adenylate Kinase; Biguanides; Bone Morphogenetic Proteins; Cell Line; Drug Synergism; Endoplasmic Reticulum Chaperone BiP; Glucose; Heat-Shock Proteins; Humans; Macrolides; Membrane Glycoproteins; Oligonucleotide Array Sequence Analysis; Oligosaccharides; Phosphorylation; Protein Processing, Post-Translational; Pyrazoles; Pyrimidines; Signal Transduction; Smad Proteins; Transcriptome; Unfolded Protein Response