Changes of PI3K/AKT/BCL2 signaling proteins in congenital Giant Nevi: melanocytes contribute to their increased survival and integrity

Abstract

Congenital Giant Nevi (CGN) are rare melanocytic lesions with the potential to regress into malignant melanoma. Simultaneous up-regulation and cooperative interactions of signaling pathways are crucial events in the pathogenesis of melanocytes. Our study aimed to identify changes in the expression and activation of proteins controlling survival and/or apoptosis of the key signaling pathways PI3K/AKT/BCL2 and Wnt/β-catenin of CGN melanocytes. We applied a model of cultured melanocytes from paired CGN and normal appearing skin, and Western blot (WB) analyzed the expression and activation profile of survival and anti-apoptotic proteins of these signaling pathways, growth pattern, cell cycle and apoptosis. WB analysis demonstrated a significant higher expression level of activated AKT and of BCL2 proteins in the CGN melanocytes compared with paired melanocytes from normal appearing skin. A relative increase in the level of GSK3 and FOXO1 proteins, down stream targets of AKT, as well as of pβ-catenin was also detected in the CGN melanocytes compared with the controls. These changes were not affected by growth of the CGN melanocytes in reduced serum (starvation). Both cell populations shared a similar growth pattern, with no significant differences in the proportion of apoptotic cells and in cell cycle fractions. These data demonstrate for the first time, changes in signaling proteins of cultured CGN melanocytes. Further, suggesting that the changes in AKT/BCL2 signaling molecules might mediate growth and anti-apoptosis processes at least in part, thus increasing the survival potential of CGN melanocytes and maintaining their integrity.     

Role of miR-107 and its signaling pathways in diseases

Abstract

MicroRNAs exert their biologic effects by targeting specific mRNAs for degradation or translational inhibition. MicroRNA-mediated regulation is complex, potentially affecting expression of the host gene, related enzymes within the same pathway or apparently distinct targets. miR-107 is found to be implicated in the pathogenesis of some diseases. This review was performed to sum up the role of miR-107 and its signaling pathways in renal diseases.     

Gap Junction Assembly: Multiple Connexin Fluorophores Identify Complex Trafficking Pathways

The assembly of gap junction channels was studied using mammalian cells expressing connexin (Cx) 26, 32 and 43 in which the carboxyl terminus was fused to green, yellow or cyan fluorescent proteins (GFP, YFP, CFP). Intracellular targeting of Cx32-CFP and 43-GFP to gap junctions was disrupted by brefeldin A treatment and resulted in a severe loss of gap junctional intercellular communication reflected by low intercellular dye transfer. Cells expressing Cx43-GFP exposed to nocodazole showed normal targeting to gap junctions and dye transfer. Cx32 and 43 thus appear to be transported and assembled into gap junctions via the classical secretory pathway. In contrast, we found that assembly of Cx26-GFP into functional gap junctions was relatively unaffected by treatment of cells with brefeldin A, but was extremely sensitive to nocodazole treatment. Coexpression of Cx26-YFP and Cx32-CFP indicated a different intracellular distribution that was accentuated in the presence of brefeldin A, with the gap junctions in these cells constructed predominantly of Cx26-YFP. A site specific mutation in the first transmembrane domain that distinguished Cx32 from Cx26 (Cx32128L) resulted in the adoption of the trafficking properties of Cx26 as well as its unusual post-translational membrane integration characteristics. The results indicate that multiple intracellular connexin trafficking routes exist and provide a further mechanism for regulating the connexin composition of gap junctions and thus specificity in intercellular signalling.     

The primary cilium

The primary cilium is an antenna-like organelle that plays a vital role in organ generation and maintenance. It protrudes from the cell surface where it receives signals from the surrounding environment and relays them into the cell. These signals are then integrated to give the required outputs in terms of proliferation, differentiation, migration and polarization that ultimately lead to organ development and homeostasis. Defects in cilia function underlie a wide range of diverse but related human developmental or degenerative diseases. Collectively known as ciliopathies, these disorders present with varying severity and multiple organ involvement. The appreciation of the medical importance of the primary cilium has stimulated a huge effort into studies of the underlying cellular mechanisms. These in turn have revealed that ciliopathies result not only from defective assembly or organization of the primary cilium, but also from impaired ciliary signaling. This special edition of Organogenesis contains a set of review articles that highlight the role of the primary cilium in organ development and homeostasis, much of which has been learnt from studies of the associated human diseases. Here, we provide an introductory overview of our current understanding of the structure and function of the cilium, with a focus on the signaling pathways that are coordinated by primary cilia to ensure proper organ generation and maintenance.     

海藻酸转化生物乙醇研究进展

作为第三代生物燃料,大型褐藻类生物质转化燃料乙醇的研究受到广泛的关注。但是,现有的乙醇工业菌株并不能利用褐藻中的主要成分海藻酸,这个问题是海藻生物乙醇实现工业化生产的主要技术难关。近几年随着对海藻酸裂解酶和海藻酸降解菌代谢途径的深入研究,科研人员构建了不同的海藻酸发酵菌株,为高效转化大型海藻生产生物乙醇提供了可行的技术基础。这篇文章对海藻酸资源概况和海藻酸转化生物乙醇存在的科学问题及其研究进展进行了综述。     

Colon cancer therapy by focusing on colon cancer stem cells and their tumor microenvironment

Despite many advances and optimization in colon cancer treatment, tumor recurrence and metastases make the development of new therapies necessary. Colon cancer stem cells (CCSCs) are considered as the main triggering factor of cancer progression, recurrence, and metastasis. CCSCs as a result of accumulated genetic and epigenetic alterations and also complex interconnection with the tumor microenvironment (TME) can evolve and convert to full malignant cells. Mounting evidence suggests that in cancer therapy both CCSCs and non-CCSCs in TME have to be regarded to break through the limitation of current therapies. In this regard, stem cell capabilities of some non-CCSCs may arise inside the TME condition. Therefore, a deep knowledge of regulatory mechanisms, heterogeneity, specific markers, and signaling pathways of CCSCs and their interconnection with TME components is needed to improve the treatment of colorectal cancer and the patient's life quality. In this review, we address current different targeted therapeutic options that target cell surface markers and signaling pathways of CCSCs and other components of TME. Current challenges and future perspectives of colon cancer personalized therapy are also provided here. Taken together, based on the deep understanding of biology of CCSCs and using three-dimensional culture technologies, it can be possible to reach successful colon cancer eradication and improvise combination targeted therapies against CCSCs and TME.     

Comparative analysis of activities of vital defence enzymes during induction of resistance in pearl millet against downy mildew

Pearl millet [Pennisetum glaucum (L.) R. Br.] has the seventh largest annual production in the world giving it significant economic importance. Although generally well adapted to the growing conditions in arid and semi-arid regions, major constraints to yields are susceptibility to downy mildew disease caused by the oomycete Sclerospora graminicola (Sacc.) Schroet. Induction of resistance against downy mildew disease of pearl millet has been well established using various biotic and abiotic inducers. The present study demonstrated the comparative analysis of the involvement of the important defence enzymes like β-1,3-Glucanase, chitinase, phenylalanine ammonia-lyase (PAL), peroxidase (POX), polyphenol oxidase (PPO) and lipoxygenase (LOX) during induced systemic resistance (ISR) mediated by inducers like Benzo(1,2,3)-thiadiazole-7-carbothionic acid-S-methyl ester (BTH), Beta amino butyric acid (BABA), Chitosan and Cerebroside against pearl millet downy mildew disease. Native-PAGE showed six POX isozymes in all categories of uninoculated pearl millet seedlings and maximum intensity of bands was noticed in resistant seedlings. After inoculation in Cerebroside-treated seedlings, there were seven isoforms, POX-4 was not present in any other seedlings. Native-PAGE analysis showed the presence of five PPO isozymes in all categories of uninoculated pearl millet seedlings and after inoculation seven isoforms of PPO-7 were noticed, and the intensity of banding was more in resistant and Cerebroside-treated seedlings. The isoforms PPO-3 were present as an extra band after inoculation in all seedlings. Isoform PPO-7, though found in all seedlings, was very prominent in Chitosan- and Cerebroside-treated seedlings. β-1,3-Glucanase Native-PAGE analysis showed the presence of only one isozyme in all categories of uninoculated/inoculated pearl millet seedlings. Glu-1 isozyme was very prominent in all seedlings including resistant and susceptible seedlings. Among the induced resistant seedlings, highest intensity was observed in Cerebroside-treated seedlings. Native-PAGE analysis showed the presence of three LOX isozymes in all categories of uninoculated pearl millet seedlings, and the intensity of banding pattern was very low in BTH-treated seedlings. LOX-1 and LOX-2 were very prominent in resistant, Chitosan- and Cerebroside-treated seedlings. Upon inoculation, one extra band, LOX-3, was exclusively noticed in Cerebroside-treated seedlings. In inoculated seedlings, LOX-1, LOX-2 and LOX-4 were very prominent in Chitosan Cerebroside-treated seedlings compared to other seedlings.