Nuclear receptors and pathogenesis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a median overall survival time of 5 mo and the five years survival less than 5%, a rate essentially unchanged over the course of the years. A well defined progression model of accumulation of genetic alterations ranging from single point mutations to gross chromosomal abnormalities has been introduced to describe the origin of this disease. However, due to the its subtle nature and concurring events PDAC cure remains elusive. Nuclear receptors (NR) are members of a large superfamily of evolutionarily conserved ligand-regulated DNA-binding transcription factors functionally involved in important cellular functions ranging from regulation of metabolism, to growth and development. Given the nature of their ligands, NR are very tempting drug targets and their pharmacological modulation has been widely exploited for the treatment of metabolic and inflammatory diseases. There are now clear evidences that both classical ligand-activated and orphan NR are involved in the pathogenesis of PDAC from its very early stages; nonetheless many aspects of their role are not fully understood. The purpose of this review is to highlight the striking connections that link peroxisome proliferator activated receptors, retinoic acid receptors, retinoid X receptor, androgen receptor, estrogen receptors and the orphan NR Nur, chicken ovalbumin upstream promoter transcription factor II and the liver receptor homologue-1 receptor to PDAC development, connections that could lead to the identification of novel therapies for this disease.

Emerging role of the orphan nuclear receptor estrogen-related receptor gamma in liver metabolic diseases

Estrogen-related receptor gamma(ERRg)is one of three members of the ERR family and remains an orphan,as there are no known natural ligands.ERRg is an inducible transcription factor,and its ligandindependent transcriptional activity is regulated by co-regulator interactions and post-transcriptional modifications.Recent findings from animal models show that ERRg,as a downstream mediator of multiple extracellular signals,plays a key role in coordinating endocrine and metabolic signals,resulting in changes in glucose,alcohol,lipid,and iron metabolism in the liver.Therefore,dysregulation of this receptor contributes to the pathogenesis of metabolic diseases such as hyperglycemia,insulin resistance,and alcoholic liver injury.Interestingly,ERRg is also involved in responses to bacterial infection.These findings establish the importance of ERRg in the endocrine and metabolic control of liver metabolism,and suggest that ERRg may be a promising therapeutic target for metabolic diseases of the liver.

Protective Effect of Norcantharidin on Collagen-Induced Arthritis Rats

Objective： To observe the effect of norcantharidin（NCTD） on collagen-induced arthritis（CIA） rats. Methods： Sixty Sprague-Dawley（SD） rats were randomly divided into 6 groups（n=10）： normal group, CIA model group（model group）, NCTD low-dose group [1.35 mg/（kg·d）], NCTD middle-dose group [2.7 mg/（kg·d）], NCTD high-dose group [5.4 mg/（kg·d）] and methotrexate（MTX） group [1.8 mg/（kg/w）]. Anesthetized rats were sacrificed by luxation of cervical vertebra after 4 weeks of administration. The arthritis scores were evaluated twice a week. The pathological changes in the ankle joints of rats were observed by hematoxylin-eosin（H＆E） staining. The serum levels of interleukin（IL） 1β, IL-6, tumor necrosis factor（TNF）-α, vascular endothelial growth factor（VEGF）, IL-17 and transform growth factor（TGF） β were detected by enzyme linked immunosorbent assay（ELISA）. The mRNA expression of retinoid-related orphan nuclear receptor γ t（ROR γ t） and forkhead box P3（Foxp3） in peripheral blood lymphocytes were confirmed by real-time polymerase chain reaction. Results： MTX and high-dose NCTD not only decreased the arthritis scores but also alleviated the pathological changes in CIA rats＇ ankle joints compared with the model group（P〈0.05 or P〈0.01）. All doses of NCTD significantly inhibited the serum levels of IL-6, IL-17 and TNF-α in CIA rats（P〈0.05）. Only middle-and high-dose of NCTD prominently decreased serum IL-1β and TGF-β levels of CIA rats（P〈0.05）. However, NCTD has no effect on vascular endothelial growth factor（VEGF） level in CIA rats. The Foxp3 mRNA expression in all NCTD groups were increased significantly than in the model group（P〈0.05）. The mRNA expression of RORγt in NCTD high-dose group was decreased apparently in comparison with the model group（P〈0.05）. Conclusion： NCTD showed therapeutic effect on CIA rats by inhibition of cytokines and regulation of Th17/Treg cells.