MO-OH-Nap and SAHA induce distinct patterns of gene expression in the multiple myeloma cell line U266.
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ABSTRACT: Tropolones are small organic compounds with metal-directing moieties. Functionally, tropolones inhibit the proliferation of cancer cell lines, possibly through the inhibition of metalloenzymes such as select histone deacetylases (HDACS). Pan-HDAC inhibitors are therapeutically beneficial in the treatment of multiple myeloma albeit with significant side-effects likely owning to their lack of specificity. It was therefore hypothesized that tropolones might have anti-myeloma activities. To this end, a series of novel a-substituted tropolones were evaluated for cytotoxic effects in multiple myeloma cells. While all tested tropolones showed some level of toxicity, MO-OH-Nap had consistently low EC50 values between 1-11 mM in all three cell lines tested and was used for subsequent experiments. MO-OH-Nap was found to induce apoptosis in a concentration-dependent manner. Time course experiments demonstrated that MO-OH-Nap promotes caspase cleavage in a time-frame that was distinct from the pan-HDAC inhibitor SAHA. Furthermore, MO-OH-Nap- and SAHA-treated cells possess unique gene expression patterns, suggesting they promote apoptosis via different mechanisms. In particular, MO-OH-Nap increases the expression of markers associated with endoplasmic reticulum stress and the unfolded protein response. Synergistic cytotoxic effects were observed when cells were treated with the combination of MO-OH-Nap and the proteasome inhibitor bortezomib. However, treatment with MO-OH-Nap did not abrogate the bortezomib-induced increase in aggresomes, consistent with an HDAC6-independent mechanism for the observed synergy. Collectively, these finding support further investigation into the usefulness of a-substituted tropolones as anti-myeloma agents.
ORGANISM(S): Homo sapiens
PROVIDER: GSE93099 | GEO | 2018/01/01
SECONDARY ACCESSION(S): PRJNA360002
REPOSITORIES: GEO
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