Aims/hypothesis Liraglutide is a glucagon-like peptide-1 (GLP-1) analogue that has been demonstrated to successfully treat diabetes and promote weight loss. The mechanisms by which liraglutide confers weight loss remain to be fully clarified. Thus, we investigated whether GLP-1 receptors are expressed in human brains and whether liraglutide administration affects neural responses to food cues in diabetic individuals (primary outcome). Methods In 22 consecutively studied human brains, expression of GLP-1 receptors in the hypothalamus, medulla oblongata and parietal cortex was examined using immunohistochemistry. In a randomised (assigned by the pharmacy using a randomisation enrolment table), placebo-controlled, double-blind, crossover trial, 21 individuals with type 2 diabetes (18 included in analysis due to lack or poor quality of data) were treated with placebo and liraglutide for a total of 17 days each (0.6 mg for 7 days, 1.2 mg for 7 days, and 1.8 mg for 3 days). Participants were eligible if they had type 2 diabetes and were currently being treated with lifestyle changes or metformin. Participants, caregivers, people doing measurements and/or examinations, and people assessing the outcomes were blinded to the medication assignment. We studied metabolic changes as well as neurocognitive and neuroimaging (functional MRI) of responses to food cues at the clinical research centre of Beth Israel Deaconess Medical Center. Results Immunohistochemical analysis revealed the presence of GLP-1 receptors on neurons in the human hypothalamus, medulla and parietal cortex. Liraglutide decreased activation of the parietal cortex in response to highly desirable (vs less desirable) food images (p < 0.001; effect size: placebo 0.53 ± 0.24, liraglutide −0.47 ± 0.18). No significant adverse effects were noted. In a secondary analysis, we observed decreased activation in the insula and putamen, areas involved in the reward system. Furthermore, we showed that increased ratings of hunger and appetite correlated with increased brain activation in response to highly desirable food cues while on liraglutide, while ratings of nausea correlated with decreased brain activation. Conclusions/interpretation For the first time, we demonstrate the presence of GLP-1 receptors in human brains. We also observe that liraglutide alters brain activity related to highly desirable food cues. Our data point to a central mechanism contributing to, or underlying, the effects of liraglutide on metabolism and weight loss. Future studies will be needed to confirm and extend these findings in larger samples of diabetic individuals and/or with the higher doses of liraglutide (3 mg) recently approved for obesity. Trial registration ClinicalTrials.gov NCT01562678 Funding The study was funded by Novo Nordisk, NIH UL1 RR025758 and 5T32HD052961.

Background Tumor immune cell infiltrates are essential in hindering cancer progression and may complement the TNM classification. CD8+ and CD163+ cells have prognostic impact in breast cancer but their spatial heterogeneity has not been extensively explored in this type of cancer. Here, their potential as prognostic biomarkers was evaluated, depending on their combined densities in the tumor center (TC) and the tumor invasive margin (IM). Methods CD8+ and CD163+ cells were quantified by immunohistochemistry of formalin-fixed, paraffin-embedded (FFPE) tumor tissue samples from a cohort totaling 162 patients with histologically-confirmed primary invasive non-metastatic ductal breast cancer diagnosed between 2000 and 2015. Clinical follow-up (median 6.9 years) was available for 97 of these patients. Results Differential densities of CD8+ and CD163+ cells in the combined TC and IM compartments (i.e., high(H)/low(L), respectively for CD8+ cells and the reverse L/H combination for CD163+ cells) were found to have significant prognostic value for survival, and allowed better patient stratification than TNM stage, tumor size, lymph node invasion and histological grade. The combined evaluation of CD8+ and CD163+ cell densities jointly in TC and IM further improves prediction of clinical outcomes based on disease-free and overall survival. Patients having the favorable immune signatures had favorable clinical outcomes despite poor clinicopathological parameters. Conclusions Given the important roles of CD8+ and CD163+ cells in regulating opposing immune circuits, adding an assessment of their differential densities to the prognostic biomarker armamentarium in breast cancer would be valuable. Larger validation studies are necessary to confirm these findings. Trial registrations Study code: IRB-ID 6079/448/10-6-13 Date of approval: 10/06/2013 Retrospective study (2000–2010) First patient prospectively enrolled 14/2/2014

Kallikrein-related peptidase 6 (KLK6) is a serine protease that is aberrantly altered in various types of cancer, but its role in non-melanoma skin cancer has not been investigated. KLK6 is active in epidermis and has been linked to normal skin differentiation. Thus, we investigated whether it could be implicated in skin tumorigenesis in vivo. Carcinogenesis was induced in Klk6-/- mice by epidermal application of 7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol 13-acetate (DMBA/TPA), and multistage skin tumor development and progression was monitored closely until squamous cell carcinomas (SCCs) and invasive tumors formed. Klk6-/- (but also Klk6+/-) mice were highly resistant to tumor growth/development manifested by their highly diminished numbers and delayed onset of tumors compared with wild-type (wt) mice. Histological analyses of the few tumors that developed in Klk6-/- after prolonged (>1 year) chemical challenge revealed that these were mainly benign papillomas, whereas in wt mice tumors progressed to SCCs. Inflammation was attenuated in Klk6-/- skin following chronic exposure to TPA, indicated by markedly low expression of proinflammatory cytokines, in direct contrast to wt. Further, in Klk6-/- mice, the ability of implanted nascent PDVC57 skin cancer cells to form tumors was highly diminished. Our study identified KLK6 as a new tumor-promoting factor of early skin cancer and suggested that KLK6 is an important molecular link in the development of skin inflammation and in tumor-promoting inflammatory processes.