Itraconazole as a Noncastrating Treatment for Biochemically Recurrent Prostate Cancer: A Phase 2 Study.

BACKGROUND: Patients with biochemically recurrent prostate cancer and short prostate-specific antigen doubling time (PSADT) are at risk for metastasis yet may wish to avoid androgen deprivation therapy. Itraconazole may have antitumor activity without affecting circulating androgen levels. We therefore evaluated itraconazole as a potentially noncastrating treatment approach in biochemically recurrent prostate cancer. PATIENTS AND METHODS: Patients with biochemically recurrent prostate cancer and PSADT ≤ 15 months, with serum testosterone > 150 ng/dL, were prospectively enrolled. The primary end point was the proportion of patients who experienced ≥ 50% decline from baseline in serum prostate-specific antigen (PSA) by week 12. RESULTS: Twenty-one patients were enrolled. The median (range) age, baseline PSA, and PSADT at study entry was 72 (49-76) years, 7.6 (1.5-45.5) ng/mL, and 5.7 (1.2-13.0) months, respectively. Among 19 patients with evaluable data, 1 patient (5%) had a > 50% PSA decline. Nine patients (47%) experienced any PSA decline (mean decline 25.0%, range 2%-60%) by week 12. Among 10 patients without a PSA decline, the on-treatment versus pretreatment PSADT was not significantly longer (median 6.8 vs. 4.3 months, P = .17). There was no significant change from baseline to week 12 in serum testosterone (median change = 32.4%, P = .21) or androstenedione (median change = -8.3%, P = .85). The most common adverse events were edema (52%), fatigue (38%), hypertension (24%), and hypokalemia (24%). CONCLUSION: Itraconazole modulates serum PSA levels without lowering serum testosterone. However, the magnitude of effect is modest, and treatment carries risk of toxicities associated with mineralocorticoid excess.

Beige Adipocyte Maintenance Is Regulated by Autophagy-Induced Mitochondrial Clearance.

Beige adipocytes gained much attention as an alternative cellular target in anti-obesity therapy. While recent studies have identified a number of regulatory circuits that promote beige adipocyte differentiation, the molecular basis of beige adipocyte maintenance remains unknown. Here, we demonstrate that beige adipocytes progressively lose their morphological and molecular characteristics after withdrawing external stimuli and directly acquire white-like characteristics bypassing an intermediate precursor stage. The beige-to-white adipocyte transition is tightly coupled to a decrease in mitochondria, increase in autophagy, and activation of MiT/TFE transcription factor-mediated lysosome biogenesis. The autophagy pathway is crucial for mitochondrial clearance during the transition; inhibiting autophagy by uncoupled protein 1 (UCP1(+))-adipocyte-specific deletion of Atg5 or Atg12 prevents beige adipocyte loss after withdrawing external stimuli, maintaining high thermogenic capacity and protecting against diet-induced obesity and insulin resistance. The present study uncovers a fundamental mechanism by which autophagy-mediated mitochondrial clearance controls beige adipocyte maintenance, thereby providing new opportunities to counteract obesity.

Phosphoproteomics Identifies CK2 as a Negative Regulator of Beige Adipocyte Thermogenesis and Energy Expenditure.

Catecholamines promote lipolysis both in brown and white adipocytes, whereas the same stimuli preferentially activate thermogenesis in brown adipocytes. Molecular mechanisms for the adipose-selective activation of thermogenesis remain poorly understood. Here, we employed quantitative phosphoproteomics to map global and temporal phosphorylation profiles in brown, beige, and white adipocytes under ß3-adrenenoceptor activation and identified kinases responsible for the adipose-selective phosphorylation profiles. We found that casein kinase2 (CK2) activity is preferentially higher in white adipocytes than brown/beige adipocytes. Genetic or pharmacological blockade of CK2 in white adipocytes activates the thermogenic program in response to cAMP stimuli. Such activation is largely through reduced CK2-mediated phosphorylation of class I HDACs. Notably, inhibition of CK2 promotes beige adipocyte biogenesis and leads to an increase in whole-body energy expenditure and ameliorates diet-induced obesity and insulin resistance. These results indicate that CK2 is a plausible target to rewire the ß3-adrenenoceptor signaling cascade that promotes thermogenesis in adipocytes.

Genetic and functional characterization of clonally derived adult human brown adipocytes.

Brown adipose tissue (BAT) acts in mammals as a natural defense system against hypothermia, and its activation to a state of increased energy expenditure is believed to protect against the development of obesity. Even though the existence of BAT in adult humans has been widely appreciated, its cellular origin and molecular identity remain elusive largely because of high cellular heterogeneity within various adipose tissue depots. To understand the nature of adult human brown adipocytes at single cell resolution, we isolated clonally derived adipocytes from stromal vascular fractions of adult human BAT from two individuals and globally analyzed their molecular signatures. We used RNA sequencing followed by unbiased genome-wide expression analyses and found that a population of uncoupling protein 1 (UCP1)-positive human adipocytes possessed molecular signatures resembling those of a recruitable form of thermogenic adipocytes (that is, beige adipocytes). In addition, we identified molecular markers that were highly enriched in UCP1-positive human adipocytes, a set that included potassium channel K3 (KCNK3) and mitochondrial tumor suppressor 1 (MTUS1). Further, we functionally characterized these two markers using a loss-of-function approach and found that KCNK3 and MTUS1 were required for beige adipocyte differentiation and thermogenic function. The results of this study present new opportunities for human BAT research, such as facilitating cell-based disease modeling and unbiased screens for thermogenic regulators.