Expression of histone deacetylase (HDAC) family members in bortezomib-refractory multiple myeloma and modulation by panobinostat.

AIM: Multiple myeloma (MM) is a hematological malignancy of antibody-producing mature B cells or plasma cells. The proteasome inhibitor, bortezomib, was the first-in-class compound to be FDA approved for MM and is frequently utilized in induction therapy. However, bortezomib refractory disease is a major clinical concern, and the efficacy of the pan-histone deacetylase inhibitor (HDACi), panobinostat, in bortezomib refractory disease indicates that HDAC targeting is a viable strategy. Here, we utilized isogenic bortezomib resistant models to profile HDAC expression and define baseline and HDACi-induced expression patterns of individual HDAC family members in sensitive vs. resistant cells to better understanding the potential for targeting these enzymes. METHODS: Gene expression of HDAC family members in two sets of isogenic bortezomib sensitive or resistant myeloma cell lines was examined. These cell lines were subsequently treated with HDAC inhibitors: panobinostat or vorinostat, and HDAC expression was evaluated. CRISPR/Cas9 knockdown and pharmacological inhibition of specific HDAC family members were conducted. RESULTS: Interestingly, HDAC6 and HDAC7 were significantly upregulated and downregulated, respectively, in bortezomib-resistant cells. Panobinostat was effective at inducing cell death in these lines and modulated HDAC expression in cell lines and patient samples. Knockdown of HDAC7 inhibited cell growth while pharmacologically inhibiting HDAC6 augmented cell death by panobinostat. CONCLUSION: Our data revealed heterogeneous expression of individual HDACs in bortezomib sensitive vs. resistant isogenic cell lines and patient samples treated with panobinostat. Cumulatively our findings highlight distinct roles for HDAC6 and HDAC7 in regulating cell death in the context of bortezomib resistance.

High Rates of Obesity at Presentation Persist into Survivorship across Childhood Cancer Types.

Background: Subtypes of pediatric oncology patients and childhood cancer survivors who are overweight or obese have worse prognosis than their healthy-weighted peers. Several studies have examined weight status in either pediatric patients or survivors with acute leukemia, but few have compared these data across various diagnoses. Objectives: We examined BMI from oncology diagnosis or presentation, through treatment, and into survivorship across the most common cancer types seen in pediatric oncology. Methods: Patients were categorized into three oncologic diagnoses: leukemia and lymphoma (n = 69), neural tumors (n = 80), and non-neural solid tumors (n = 80) at yearly intervals over the course of 11 years. To allow for comparisons across age groups, BMI percentiles were calculated with <5th percentile classified as underweight (n = 11), the 5th-84th percentile classified as a healthy weight (n = 129), and above the 85th percentile classified as overweight and obese (n = 87). Results: At presentation, 45.6% of leukemia and lymphoma patients were overweight or obese, and 44.3% of neural tumor patients were overweight or obese. These high obesity rates persisted into survivorship. Compared to the non-neural tumor group, the leukemia and lymphoma group had a significant increase in BMI percentile over time, while the neural tumor group did not. Conclusions: Pediatric patients with leukemia, lymphoma, and neural tumors and who are overweight or obese at presentation continue this trend into survivorship, indicating a need for management of overweight and obesity through lifestyle interventions concurrent with therapy.

Behavior modulates effective connectivity between cortex and striatum.

It has been notoriously difficult to understand interactions in the basal ganglia because of multiple recurrent loops. Another complication is that activity there is strongly dependent on behavior, suggesting that directional interactions, or effective connections, can dynamically change. A simplifying approach would be to examine just the direct, monosynaptic projections from cortex to striatum and contrast this with the polysynaptic feedback connections from striatum to cortex. Previous work by others on effective connectivity in this pathway indicated that activity in cortex could be used to predict activity in striatum, but that striatal activity could not predict cortical activity. However, this work was conducted in anesthetized or seizing animals, making it impossible to know how free behavior might influence effective connectivity. To address this issue, we applied Granger causality to local field potential signals from cortex and striatum in freely behaving rats. Consistent with previous results, we found that effective connectivity was largely unidirectional, from cortex to striatum, during anesthetized and resting states. Interestingly, we found that effective connectivity became bidirectional during free behaviors. These results are the first to our knowledge to show that striatal influence on cortex can be as strong as cortical influence on striatum. In addition, these findings highlight how behavioral states can affect basal ganglia interactions. Finally, we suggest that this approach may be useful for studies of Parkinson's or Huntington's diseases, in which effective connectivity may change during movement.