Comparative aspects of the pineal/melatonin system of poikilothermic vertebrates

Abstract: The pineal gland of poikilothermic vertebrates originates as an evagination from the diencephalic roof between the habenular and the posterior commissures, and associates with a parapineal organ to form the so-called pineal complex. The pinealocytes may be photosensitive, secretory or intermediate cells between both. Melatonin, the indoleamine secreted by the pineal, exhibits a circadian secretory rhythm that conveys environmental information to the organism. The peak melatonin secretion occurs during the night, although there are a few examples of an increase in indoleamine secretion during the day. Melatonin is also synthesized in other sites such as the retina, and it has been found in many invertebrates and unicellular organisms. The rhythmic secretory pattern of melatonin is responsible for many biological rhythms exhibited by lower vertebrates. These rhythms are abolished by pinealectomy in some species, but not in others, suggesting the existence of an extra-pineal pacemaker. The photoperiod and the temperature (especially in reptiles) are the main environmental factors affecting the secretory rhythm of melatonin. Poikilothermic vertebrates exhibit a circadian rhythmic color change, with nocturnal blanching, usually related to melatonin secretion. In amphibians, melatonin exhibits a potent skin lightening activity. However, in fishes and reptiles the melatonin effects vary with the species, the developmental stage, and the pigment cell location. Melatonin also exerts inhibitory or excitatory activity on the amphibian reproductive system, regulation of circadian locomotory activity in reptiles, and modulation of the amphibian metamorphosis. Melatonin has also a modulatory effect on the response of target cells to different hormones and high concentrations or prolonged exposure to the indoleamine may cause autodesensitization in various tissues. Binding sites of melatonin have been detected in the central nervous system and peripheral tissues of various vertebrates. The relative potencies of melatonin analogues demonstrated two subtypes of melatonin receptors (ML-1 and ML-2). A transmembrane melatonin receptor has been cloned from Xenopus laevis melanophores; it belongs to the family of the G protein-coupled receptors and exhibits 85% homology with the mammalian nervous system receptor. Melatonin binding sites in the nucleus of many cell types and its potent intracellular anti-oxidant action suggest mechanisms of action other than through the G-protein coupled receptor.     

ZIP4 Promotes Muscle Wasting and Cachexia in Mice With Orthotopic Pancreatic Tumors by Stimulating RAB27B-Regulated Release of Extracellular Vesicles From Cancer Cells

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Tumor imaging by means of proteolytic activation of cell-penetrating peptides

We have devised and tested a new strategy for selectively delivering molecules to tumor cells. Cellular association of polyarginine-based, cell-penetrating peptides (CPPs) is effectively blocked when they are fused to an inhibitory domain made up of negatively charged residues. We call these fusions activatable CPPs (ACPPs) because cleavage of the linker between the polycationic and polyanionic domains, typically by a protease, releases the CPP portion and its attached cargo to bind to and enter cells. Association with cultured cells typically increases 10-fold or more upon linker cleavage. In mice xenografted with human tumor cells secreting matrix metalloproteinases 2 and 9, ACPPs bearing a far-red-fluorescent cargo show in vivo contrast ratios of 2-3 and a 3.1-fold increase in standard uptake value for tumors relative to contralateral normal tissue or control peptides with scrambled linkers. Ex vivo slices of freshly resected human squamous cell carcinomas give similar or better contrast ratios. Because CPPs are known to import a wide variety of nonoptical contrast and therapeutic agents, ACPPs offer a general strategy toward imaging and treating disease processes associated with linker-cleaving activities such as extracellular proteases.     

Increased expression of mitogen-activated protein kinase and its upstream regulating signal in human gastric cancer

AIM: To investigate the expression of mitogen-activated protein kinases (MAPKs) and its upstream protein kinase in human gastric cancer and to evaluate the relationship between protein levels and clinicopathological parameters.METHODS: Western blot was used to measure the expression of extracellular signal-regulated kinase (ERK)-1, ERK-2, ERK-3, p38 and mitogen or ERK activated protein kinaseMEK-1 proteins in surgically resected gastric carcinoma, adjacent normal mucosa and metastatic lymph nodes from 42 patients. Immunohistochemistry was employed for their localization.RESULTS: Compared with normal tissues, the protein levels of ERK-1 (integral optical density value 159526±65760 vs 122807±65515, P=0.001), ERK-2 (168471±95051 vs 120469±72874, P<0.001), ERK-3 (118651±71513 vs 70934±68058, P<0.001), P38 (104776±51650 vs 82930±40392, P=0.048) and MEK-1 (116486±45725 vs 101434±49387, P=0.027) were increased in gastric cancer tissues. Overexpression of ERK-3 was correlated to TNM staging [average ratio of integral optic density (IOD)tumor:IODnormal in TNM Ⅰ, Ⅱ, Ⅲ, Ⅳ tumors was 1.43±0.34, 5.08±3.74, 4.99±1.08, 1.44±1.02, n=42, P=0.023] and serosa invasion (4.31±4.34 vs 2.00±2.03, P=0.037). In poorly differentiated cancers (n=33), the protein levels of ERK-1 and ERK-2 in stage Ⅲ and Ⅳ tumors were higher than those in stage Ⅰ and Ⅱ tumors (2.64±3.01 vs 1.01±0.33, P=0.022; 2.05±1.54 vs 1.24±0.40, P=0.030). Gastric cancer tissues with either lymph node involvement (2.49±2.91 vs 1.03±0.36, P=0.023; 1.98±1.49 vs 1.24±0.44, P=0.036) or serosa invasion (2.39±2.82 vs 1.01±0.35, P=0.022; 1.95±1.44 vs 1.14±0.36, P=0.015) expressed higher protein levels of ERK-1 and ERK-2. In Borrmann Ⅱ tumors, expression of ERK-2 and ERK-3 was increased comparedwith Borrmann Ⅲ tumors (2.57±1.86 vs 1.23±0.60, P=0.022; 5.50±5.05 vs 1.83±1.21, P=0.014). Borrmann Ⅳ tumors expressed higher p38 protein levels. No statistically significant difference in expression of MAPKs was found when stratified to tumor size or histological grade (P>0.05). Protein levels of ERK-2, ERK-3 and MEK-1 in metastatic lymph nodes were 2-7 folds higher than those in adjacent normal mucosa. The immunohistochemistry demonstrated that ERK-1, ERK-2, ERK-3, p38 and MEK-1 proteins were mainly localized in cytoplasm. The expression of MEK-1 in gastric cancer cells metastasized to lymph nodes was higher than that of the primary site. CONCLUSION: MAPKs, particularly ERK subclass are overexpressed in the majority of gastric cancers. Overexpression of ERKs is correlated to TNM staging, serosa invasion, and lymph node involvement. The overexpression of p38 most likely plays a prominent role in certain morphological subtypes of gastric cancers. MEK-1 is also overexpressed in gastric cancer, particularly in metastatic lymph nodes. Upregulation of MAPK signal transduction pathways may play an important role in tumorigenesis and metastatic potential of gastric cancer.     

Pixantrone plus rituximab versus gemcitabine plus rituximab in patients with relapsed aggressive B-cell non-Hodgkin lymphoma not eligible for stem cell transplantation: a phase 3, randomized,multicentre trial (PIX306)

PIX306 was a phase 3, randomised, single-blind, multicentre trial conducted in adult patients with diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL) grade 3 who relapsed after ≥1 rituximab-containing regimen and were not eligible for a stem cell transplant. Patients were randomised 1:1 to pixantrone 50 mg/m² or gemcitabine 1000 mg/m² on days 1, 8 and 15 of a 28-day cycle, combined with rituximab 375 mg/m² on day 1, for up to six cycles. Patients were followed for up to 96 weeks. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), complete response (CR) rate, overall response rate (ORR) and safety. Overall, 312 patients were randomised (median age 73·0 years). The study did not meet its primary endpoint. Median PFS [95% confidence interval (CI)] was 7·3 months (5·2–8·4) with pixantrone + rituximab (PIX + R) and 6·3 months (4·4–8·1) with gemcitabine + rituximab [GEM + R; hazard ratio (HR): 0·85; 95% CI 0·64–1·14; P = 0·28]. Median OS was 13·3 (10·1–19·8) months with PIX + R and 19·6 (12·4–31·9) months with GEM + R (HR: 1·13; 95% CI 0·83–1·53). ORR was 61·9% and 43·9% respectively and CR rate 35·5% and 21·7%. The incidence of adverse events, including cardiac events, was not statistically significant different between PIX + R and GEM + R.     

Mechanisms of Transformation by the BCR/ABL Oncogene

The Philadelphia chromosome generates a chimeric oncogene in which the BCR and c-ABL genes are fused. The product of this oncogene, BCR/ABL, has elevated ABL tyrosine kinase activity, relocates to the cytoskeleton, and phosphorylates multiple cellular substrates. BCR/ABL transforms hematopoietic cells and exerts a wide variety of biological effects, including reduction in growth factor dependence, enhanced viability, and altered adhesion of chronic myelocytic leukemia (CML) cells. Elevated tyrosine kinase activity of BCR/ABL is critical for activating downstream signal transduction and for all aspects of transformation. This review will describe mechanisms of transformation by the BCR/ABL oncogene and opportunities for clinical intervention with specific signal transduction inhibitors such as STI-571 in CML.     

Pathways Involved in Interleukin-1β–Mediated Murine Cardiomyocyte Apoptosis

Accumulating evidence suggests that interleukin-1 (IL-1) signaling plays an essential role in the pathogenesis of heart failure by inducing cardiomyocyte apoptosis, but the mechanisms of this process are poorly defined. We further explored these molecular pathways.We isolated cardiomyocytes from neonatal mice and then cultured and stimulated them with murine IL-1β in vitro. Cell apoptotic ratios were measured by means of flow cytometry. Expression of effector molecules was analyzed by means of enzyme-linked immunosorbent assay, Western blotting, and real-time quantitative polymerase chain reaction. The results showed that IL-1β induced murine cardiomyocyte apoptosis through a release of cytochrome c into cytoplasm and through caspase 3 activation. Simultaneously, IL-1β signaling promoted expression of endonuclease G and high-temperature requirement protein A2 messenger RNA. Survivin and X-linked inhibitors of apoptosis protein (IAP), members of the IAP family, were inhibited on the messenger RNA level during IL-1β–mediated cardiomyocyte apoptosis.We found that IL-1β signaling during cardiomyocyte apoptosis in vitro induced the activation of caspase-dependent and caspase-independent pathways, and inhibited IAPs. Understanding the molecular mechanisms involved in IL-1β–mediated cardiomyocyte apoptosis might assist in the design of therapeutic approaches to protect cardiomyocyte function and prevent heart failure.     

Electroacupuncture delays articular cartilage degeneration in osteoarthritis via ras-raf-mek1/2-erk1/2 signaling pathway北大核心

BACKGROUND: Previous studies have found that electroacupuncture can delay articular cartilage degeneration mediated by JAK-STAT signaling pathway through upregulating the expression level of transforming growth factor β1 as well as mRNA expression levels of STAT3, Smad3 and LepR. In the meanwhile, electroacupuncture can inhibit the mRNA expression of p38 and Fas mRNA mediated by MAPK signaling pathways, further inhibiting the apoptosis of chondrocytes. OBJECTIVE: To explore the effect of electroacupuncture on the degeneration of articular cartilage in rats with knee osteoarthritis based on Ras-Raf-MEK1/2-ERK1/2 signaling pathway. METHODS: 120 male healthy Sprague-Dawley rats aged 2 months olds were selected and randomly divided into normal, model, 15-minite electroacupuncture and 30-minute electroacupuncture groups (n=30 per group). The rats in the latter three groups received the intra-articular injection of 4% papain bilaterally, and the remaining rats received no intervention. At 2 weeks after modeling, the latter two groups were respectively given 15-and 30-minute electroacupuncture, five times weekly for consecutive 12 weeks. The morphology of the cartilage was observed by hematoxylin-eosin staining, the expression level of interleukin-1β in the synovium was detected by ELISA assay, and the protein expression levels of Ras, Raf, MEK1/2, ERK1/2, C-MYC, C-FOS, and C-JUN were detected by western blot analysis. RESULTS AND CONCLUSION: Hematoxylin-eosin staining showed that: in the model group, the cartilage surface was rough, the cartilage layer became thinner, and the cartilage structure was damaged with incomplete tidal line; in the 15and 30-minute electroacupuncture groups, the cartilage structure was complete with clear layers and complete tidal line. ELISA showed that the expression level of interleukin-1β in the model group was significantly higher than that in the normal group (P < 0.01), and the level in the 15-and 30-minute electroacupuncture groups was significantly lower than that in the model group (P < 0.05). Western blot assay found that compared with the normal group, the protein expression levels of Ras, Raf, MEK1/2, ERK1/2, C-MYC, C-FOS, and C-JUN were increased in the model group. However, all above protein levels except ERK1/2 in the 15-and 30-minute electroacupuncture groups were significantly lower than those in the model group (P < 0.01, P < 0.05). To conclude, electroacupuncture inhibits the degeneration of articular cartilage in osteoarthritis via Ras-Raf-MEK1/2-ERK1/2 signaling pathway and downregulating the expression level of interleukin-1β. © 2017, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

微小RNA在骨分化过程中的作用机制

在口腔种植治疗过程中常常会遇到骨量不足的问题,植入骨替代材料是目前临床上最主要的重建骨缺损方法之一,因此骨替代材料的成骨性能及其分子机制成为了研究热点。微小RNA（miRNA）是一种短链非编码RNA,通过转录后调控细胞分化、增殖、程序性死亡等病理生理过程。miRNA可影响成骨相关因子的表达和激活成骨相关信号转导通路中的信号转导,从而对骨组织动态改建过程进行调控。本文就miRNA与成骨细胞特异性转录因子、核心结合因子-α1基因、Smad基因、转化生长因子-β诱导因子,与骨形态发生蛋白信号转导通路、无翅型小鼠乳房肿瘤病毒整合位点家族信号转导通路、促丝裂原激活蛋白激酶信号转导通路、成脂信号转导通路以及miRNA与口腔相关材料和miRNA在骨缺损修复中的应用研究进展作一综述。