A novel and translational role for autophagy in antisense oligonucleotide trafficking and activity.

Endocytosis is a mechanism by which cells sense their environment and internalize various nutrients, growth factors and signaling molecules. This process initiates at the plasma membrane, converges with autophagy, and terminates at the lysosome. It is well-established that cellular uptake of antisense oligonucleotides (ASOs) proceeds through the endocytic pathway; however, only a small fraction escapes endosomal trafficking while the majority are rendered inactive in the lysosome. Since these pathways converge and share common molecular machinery, it is unclear if autophagy-related trafficking participates in ASO uptake or whether modulation of autophagy affects ASO activity and localization. To address these questions, we investigated the effects of autophagy modulation on ASO activity in cells and mice. We found that enhancing autophagy through small-molecule mTOR inhibition, serum-starvation/fasting, and ketogenic diet, increased ASO-mediated target reduction in vitro and in vivo. Additionally, autophagy activation enhanced the localization of ASOs into autophagosomes without altering intracellular concentrations or trafficking to other compartments. These results support a novel role for autophagy and the autophagosome as a previously unidentified compartment that participates in and contributes to enhanced ASO activity. Further, we demonstrate non-chemical methods to enhance autophagy and subsequent ASO activity using translatable approaches such as fasting or ketogenic diet.

CHD1 Promotes Sensitivity to Aurora Kinase Inhibitors by Suppressing Interaction of AURKA with Its Coactivator TPX2.

Clinical studies have shown that subsets of patients with cancer achieve a significant benefit from Aurora kinase inhibitors, suggesting an urgent need to identify biomarkers for predicting drug response. Chromodomain helicase DNA binding protein 1 (CHD1) is involved in chromatin remodeling, DNA repair, and transcriptional plasticity. Prior studies have demonstrated that CHD1 has distinct expression patterns in cancers with different molecular features, but its impact on drug responsiveness remains understudied. Here, we show that CHD1 promotes the susceptibility of prostate cancer cells to inhibitors targeting Aurora kinases, while depletion of CHD1 impairs their efficacy in vitro and in vivo. Pan-cancer drug sensitivity analyses revealed that high expression of CHD1 was associated with increased sensitivity to Aurora kinase A (AURKA) inhibitors. Mechanistically, KPNA2 served as a direct target of CHD1 and suppressed the interaction of AURKA with the coactivator TPX2, thereby rendering cancer cells more vulnerable to AURKA inhibitors. Consistent with previous research reporting that loss of PTEN elevates CHD1 levels, studies in a genetically engineered mouse model, patient-derived organoids, and patient samples showed that PTEN defects are associated with a better response to AURKA inhibition in advanced prostate cancer. These observations demonstrate that CHD1 plays an important role in modulating Aurora kinases and drug sensitivities, providing new insights into biomarker-driven therapies targeting Aurora kinases for future clinical studies. SIGNIFICANCE: CHD1 plays a critical role in controlling AURKA activation and promoting Aurora kinase inhibitor sensitivity, providing a potential clinical biomarker to guide cancer treatment.