Worldwide prevalence of esophageal
adenocarcinomas with high rates of mortality coupled with increased mutations in esophageal cells warrants investigation to understand deregulation of cell signaling pathways leading to
cancer. To this end, the current study was undertaken to unravel the cell death signatures using the model human esophageal
adenocarcinoma cell line-OE33. The strategy involved targeting the key epigenetic modulator
SIRT1, a
histone deacetylase by a small molecule inhibitor -
sirtinol.
Sirtinol induced a dose-dependent inhibition of cell viability under both normoxic and hypoxic conditions with long term impact on proliferation as shown by clonogenic assays. Signature apoptotic signaling pathways including
caspase activation and decreased Bcl-2 were observed. Proteomic analysis highlighted an array of entities affected including molecules involved in replication, transcription,
protein synthesis, cell division control, stress-related
proteins, spliceosome components,
protein processing and cell detoxification/degradation systems. Importantly, the stoichiometry of the fold changes of the affected
proteins per se could govern the cell death phenotype by
sirtinol.
Sirtinol could also potentially curb resistant and recurrent
tumors that reside in hypoxic environments. Overall, in addition to unraveling the cellular, molecular and proteomics basis of
SIRT1 inhibition, the findings open up avenues for designing novel strategies against esophageal
adenocarcinoma.