Although the global incidence of cutaneous melanoma is increasing, survival rates for patients with metastatic disease remain <10%. Novel treatment strategies are therefore urgently required, particularly for patients bearing BRAF/NRAS wild-type tumors. Targeting autophagy is a means to promote cancer cell death in chemotherapy-resistant tumors, and the aim of this study was to test the hypothesis that cannabinoids promote autophagy-dependent apoptosis in melanoma. Treatment with Δ(9)-Tetrahydrocannabinol (THC) resulted in the activation of autophagy, loss of cell viability, and activation of apoptosis, whereas cotreatment with chloroquine or knockdown of Atg7, but not Beclin-1 or Ambra1, prevented THC-induced autophagy and cell death in vitro. Administration of Sativex-like (a laboratory preparation comprising equal amounts of THC and cannabidiol (CBD)) to mice bearing BRAF wild-type melanoma xenografts substantially inhibited melanoma viability, proliferation, and tumor growth paralleled by an increase in autophagy and apoptosis compared with standard single-agent temozolomide. Collectively, our findings suggest that THC activates noncanonical autophagy-mediated apoptosis of melanoma cells, suggesting that cytotoxic autophagy induction with Sativex warrants clinical evaluation for metastatic disease.

We performed a systematic review of the clinical, molecular, and biochemical features of polymerase gamma (POLG)-related epilepsy and current evidence on seizure management. Patients were identified from a combined electronic search of articles using Ovid Medline and Scopus databases, published from January 2000 to January 2015. Only patients with a confirmed genetic diagnosis of POLG mutations were considered. Seventy-two articles were included for analysis. We identified 128 pathogenic variants in 372 patients who had POLG-related epilepsy. Among these, 84% of the cases harbored at least one of these pathogenic variants: p.Ala467Thr, p.Trp748Ser, and p.Gly848Ser. A bimodal distribution of disease onset was present in early childhood (<5 years) and adolescence; female patients had a later presentation than male patients (median age 4.00 vs. 1.83 years, p-value = 0.041). Focal-onset seizure including convulsive, myoclonus, and occipital seizures was common at the outset and was refractory to pharmacotherapy. We confirmed that homozygous pathogenic variants located in the linker region of POLG were associated with later age of onset and longer survival compared to compound heterozygous variants. In addition, biochemical and molecular heterogeneities in different tissues were frequently observed. POLG-related epilepsy is clinically heterogeneous, and the prognosis is, in part, influenced by the location of the variants in the gene and the presence of hepatic involvement. Normal muscle and fibroblast studies do no exclude the diagnosis of POLG-related mitochondrial disease and direct sequencing of the POLG gene should be the gold standard when investigating suspected cases.

Introduction Mitochondrial dysfunction is frequently posited as a cause of aging muscle atrophy. One of the proposed mechanisms involves an age‐related accumulation of mitochondrial DNA (mtDNA) mutations and subsequent mitochondrial dysfunction. Consistent with this notion, previous studies have reported co‐localization of fiber segments with high mtDNA mutation load, severe oxidative impairment, up‐regulation of necrotic and apoptotic pathways, fiber atrophy and breakage in aged muscle. However, the significance of this mechanism is dubious as the majority of fibers harbouring high mtDNA mutation loads and oxidative damage do not exhibit atrophy. In contrast, we have reported previously that persistent denervation of muscle fibers correlates with fiber atrophy in advanced age, where over 90% of severely atrophied fibers show evidence of persistent denervation. These latter findings raise the question of what causes denervation in aging muscle. As virtually nothing is known about the potential for accumulation of mtDNA mutations to cause denervation in aging muscle, we studied neuromuscular junction (NMJ) morphology in a mouse model, exhibiting a rapid accumulation of mtDNA mutations and markedly accelerated muscle atrophy, the polymerase gamma mutator (PolGmut). Findings Our analysis revealed significantly lower (p<0.05) muscle mass in 16‐mo old PolGmut (n=4) versus 5‐mo old PolGmut mice (n=8) in tibialis anterior (TA; mean ±SD: 25.5±7.4 mg versus 44.3 ±4.7 mg), soleus (Sol: 4.5 ±0.6 mg versus 6.5 mg ±1.1 mg) and gastrocnemius (90.9 ±8.5 mg versus 122.9 ±19.7 mg). In contrast, there was not a significant reduction in muscle weight in 15 to 17‐mo old (n=11) versus 5‐mo old (n=8) WT mice in the TA (42.5 ±7.9 mg versus 43.3 ±9.1 mg), soleus (7.3 ±1.8 mg versus 5.9 ±1.9 mg) and gastrocnemius (mean weight=123.1 ±29.6 mg versus 136.4 ±26.5 mg). Furthermore, we tested the impact of aging on NMJ morphology by immunofluorescent labelling and quantitative assessment of NMJ morphology from the TA of these mice. Significant alterations (p<0.05) were found in WT mice between 5‐mo and 16‐mo including reductions in pre‐synaptic variables: nerve terminal area, nerve terminal perimeter; and in post‐synaptic variables: AChR area, AChR perimeter, AChR compactness and nerve terminal area outside the endplate. Increased nerve terminal area outside AChRs and axonal area within the endplate were also detected. Some of these changes were potentiated in 16‐mo old PolGmut, characterized by increased pre‐synaptic axon diameter and post‐synaptic fragmentation, and reductions in post‐synaptic: unoccupied AChR area, endplate area and endplate perimeter. Most of the NMJ morphology changes were associated with post‐synaptic variables in both WT and PolGmut. Conclusion Our findings show that PolGmut mice exhibit an accelerated appearance of NMJ degeneration, consistent with the possibility that mtDNA mutations may be a cause of denervation in aging muscle. Further work is underway to determine whether NMJ degeneration is related to mtDNA altera...

Summary Background The updated American Joint Committee on Cancer (AJCC) staging criteria for melanoma remain unable to identify high‐risk stage I tumour subsets. Objectives To determine the utility of epidermal autophagy and beclin 1 regulator 1 (AMBRA1)/loricrin (AMLo) expression as a prognostic biomarker for AJCC stage I cutaneous melanoma. Methods Peritumoral AMBRA1 expression was evaluated in a retrospective discovery cohort of 76 AJCC stage I melanomas. AMLo expression was correlated with clinical outcomes up to 12 years in two independent powered, retrospective validation and qualification cohorts comprising 379 AJCC stage I melanomas. Results Decreased AMBRA1 expression in the epidermis overlying primary melanomas in a discovery cohort of 76 AJCC stage I tumours was associated with a 7‐year disease‐free survival (DFS) rate of 81·5% vs. 100% survival with maintained AMBRA1 (P < 0·081). Following an immunohistochemistry protocol for semi‐quantitative analysis of AMLo, analysis was undertaken in validation (n = 218) and qualification cohorts (n = 161) of AJCC stage I melanomas. Combined cohort analysis revealed a DFS rate of 98·3% in the AMLo low‐risk group (n = 239) vs. 85·4% in the AMLo high‐risk cohort (n = 140; P < 0·001). Subcohort multivariate analysis revealed that an AMLo hazard ratio (HR) of 4·04 [95% confidence interval (CI) 1·69–9·66; P = 0·002] is a stronger predictor of DFS than Breslow depth (HR 2·97, 95% CI 0·93–9·56; P = 0·068) in stage IB patients. Conclusions Loss of AMLo expression in the epidermis overlying primary AJCC stage I melanomas identifies high‐risk tumour subsets independently of Breslow depth. What's already known about this topic? There is an unmet clinical need for biomarkers of early‐stage melanoma. Autophagy and beclin 1 regulator 1 (AMBRA1) is a proautophagy regulatory protein with known roles in cell proliferation and differentiation, and is a known tumour suppressor. Loricrin is a marker of epidermal terminal differentiation. What does this study add? AMBRA1 has a functional role in keratinocyte/epidermal proliferation and differentiation. The combined decrease/loss of peritumoral AMBRA1 and loricrin is associated with a significantly increased risk of metastatic spread in American Joint Committee on Cancer (AJCC) stage I tumours vs. melanomas, in which peritumoral AMBRA1 and loricrin are maintained, independently of Breslow depth. What is the translational message? The integration of peritumoral epidermal AMBRA1/loricrin biomarker expression into melanoma care guidelines will facilitate more accurate, personalized risk stratification for patients with AJCC stage I melanomas, thereby facilitating stratification for appropriate follow‐up and informing postdiagnostic investigations, including sentinel lymph node biopsy, ultimately resulting in improved disease outcomes and rationalization of healthcare costs.