Ras modulates Myc activity to repress thrombospondin-1 expression and increase tumor angiogenesis

Tumor angiogenesis is postulated to be regulated by the balance between pro- and anti-angiogenic factors. We demonstrate that the critical step in establishing the angiogenic capability of human cells is the repression of the critical anti-angiogenic factor, thrombospondin-1 (Tsp-1). This repression is essential for tumor formation by mammary epithelial cells and kidney cells engineered to express SV40 early region proteins, hTERT, and H-RasV12. We have uncovered the signaling pathway leading from Ras to Tsp-1 repression. Ras induces the sequential activation of PI3 kinase, Rho, and ROCK, leading to activation of Myc through phosphorylation; phosphorylation of Myc via this mechanism enables it to repress Tsp-1 expression. We thus describe a novel mechanism by which the cooperative activity of the oncogenes, ras and myc, leads directly to angiogenesis and tumor formation.     

Naringenin Decreases α-Synuclein Expression and Neuroinflammation in MPTP-Induced Parkinson’s Disease Model in Mice

The present study was designed to ascertain the role of naringenin (NGN), a citrus fruit flavanone, against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced α-synuclein (SYN) pathology and neuroinflammation in a mouse model. NGN was administered to C57BL/6J mice once a day for 5 consecutive days prior to the MPTP intoxication. On day 5, 40–50 min after the NGN or vehicle administration, MPTP was injected in two divided doses (2× 40 mg/kg, i.p. at 16 h apart). The animals were observed for motor functions 48 h after the first MPTP injection. The animals were then euthanized, the brains collected to analyze SYN pathology, cytokines, and oxidative stress levels in the substantia nigra region. The NGN significantly downregulated SYN and upregulated dopamine transporter (DAT) and tyrosine hydroxylase (TH) protein expressions. It also downregulated tumor necrosis factor-α (TNFα) and interleukin 1β (IL1β) mRNA expressions and improved superoxide dismutase levels. It also reduced glutathione levels when compared to vehicle-treated PD animals. The upregulation of TH corroborates to an increase in dopamine, DOPAC, and homovanillic acid turnover and motor functions with NGN treatment. To summarize, NGN, a dietary flavone, has the potential to counteract MPTP-induced dopaminergic degeneration by regulating SYN pathology, neuroinflammation, and oxidative stress. This warrants the investigation of NGN’s potential effects in a genetic model of PD.     

Gradient biomaterials for soft-to-hard interface tissue engineering

Interface tissue engineering (ITE) is a rapidly developing field that aims to fabricate biological tissue alternates with the goal of repairing or regenerating the functions of diseased or damaged zones at the interface of different tissue types (also called "interface tissues"). Notable examples of the interface tissues in the human body include ligament-to-bone, tendon-to-bone and cartilage-to-bone. Engineering interface tissues is a complex process, which requires a combination of specialized biomaterials with spatially organized material composition, cell types and signaling molecules. Therefore, the use of conventional biomaterials (monophasic or composites) for ITE has certain limitations to help stimulate the tissue integration or recreating the structural organization at the junction of different tissue types. The advancement of micro- and nanotechnologies enable us to develop systems with gradients in biomaterials properties that encourage the differentiation of multiple cell phenotypes and subsequent tissue development. In this review we discuss recent developments in the fabrication of gradient biomaterials for controlling cellular behavior such as migration, differentiation and heterotypic interactions. Moreover, we give an overview of potential uses of gradient biomaterials in engineering interface tissues such as soft tissues (e.g. cartilage) to hard tissues (e.g. bone), with illustrated experimental examples. We also address fundamentals of interface tissue organization, various gradient biomaterials used in ITE, micro- and nanotechnologies employed for the fabrication of those gradients, and certain challenges that must be met in order for ITE to reach its full potential.     

The macrophage odorant receptor Olfr78 mediates the lactate-induced M2 phenotype of tumor-associated macrophages

Expression and function of odorant receptors (ORs), which account for more than 50% of G protein–coupled receptors, are being increasingly reported in nonolfactory sites. However, ORs that can be targeted by drugs to treat diseases remain poorly identified. Tumor-derived lactate plays a crucial role in multiple signaling pathways leading to generation of tumor-associated macrophages (TAMs). In this study, we hypothesized that the macrophage OR Olfr78 functions as a lactate sensor and shapes the macrophage–tumor axis. Using Olfr78^+/+ and Olfr78^−/− bone marrow–derived macrophages with or without exogenous Olfr78 expression, we demonstrated that Olfr78 sensed tumor-derived lactate, which was the main factor in tumor-conditioned media responsible for generation of protumoral M2-TAMs. Olfr78 functioned together with Gpr132 to mediate lactate-induced generation of protumoral M2-TAMs. In addition, syngeneic Olfr78-deficient mice exhibited reduced tumor progression and metastasis together with an increased anti- versus protumoral immune cell population. We propose that the Olfr78–lactate interaction is a therapeutic target to reduce and prevent tumor progression and metastasis.

Odorant receptors (ORs) are the largest subfamily of G protein–coupled receptors (GPCRs), accounting for ∼400 of more than 800 human GPCRs and 1,000 of an estimated 1,700 mouse GPCRs (1, 2). GPCRs are a major type of drug target and have been extensively studied (3). However, studies have focused on the functions of ORs in the nose, and investigations of their ectopic expression and functions in nonolfactory tissues are lacking (4, 5). The development of next-generation sequencing techniques, such as bulk (6) and single-cell (7, 8) RNA sequencing, has made it possible to detect and analyze genes that are lowly expressed or expressed in certain cell types (4, 5). Consequently, research into the functions of ectopic ORs is growing rapidly, and such ORs have been suggested as potential drug targets (9–11). Nevertheless, studies of ectopic ORs as drug targets in tumors are limited due to the lack of identification and characterization of ORs in pathophysiological conditions in vivo, such as in the tumor microenvironment (TME).GPCRs are traditionally thought to be monomers, but recent evidence demonstrates they form dimers or oligomers for their normal trafficking and function (12). Few GPCRs strictly require heterodimerization for surface expression and functional activity. Therefore, a detailed study of GPCR heterodimerization as part of their functional activation is of tremendous clinical importance because GPCRs are the molecular targets of numerous therapeutic drugs (12). For instance, heteromerization of Gpr132 (also known as G2A) with other GPCRs enhances ligand sensitivity (13). Gpr132 differentially couples with multiple G proteins, including Gs, depending on which ligand binds, and this correlates with its ability to induce cyclic adenosine monophosphate elevation (14). An OR was also reported to increase its surface expression through heterodimerization with its partner GPCR (15). However, it is unknown whether an ectopic OR functions by heteromerizing with GPCRs in pathophysiological conditions.Tumor-associated macrophages (TAMs) are one of the main components of the TME and promote tumor progression, angiogenesis, invasion, metastasis, and immunosuppression (16–18). Macrophages differentiate into protumoral M2-TAMs in response to stimuli such as lactate (19), interleukin (IL)-4, IL-13, IL-10, macrophage colony-stimulating factor, and corticosteroids (20) in the TME. Lactate produced in the tumor landscape is transported by monocarboxylate transporters expressed in various cell types and used as a carbon source by lactate dehydrogenase (21). It also acts as a signaling molecule that binds to GPCRs (22). Lactate affects many cell types, including macrophages, effector T cells, and regulatory T cells (Tregs), in the TME (21). Among these, macrophage polarization to generate protumoral M2-TAMs plays a crucial role in immunomodulation in the TME, which in turn promotes tumor progression and metastasis (19). However, cross-talk between lactate and macrophages leading to generation of protumoral M2-TAMs that enhance tumor progression remains poorly defined.In this study, we hypothesized that the lactate-activated OR Olfr78 (OR51E2, a human analog) functions as a macrophage lactate sensor. We sought to determine whether Olfr78 on bone marrow–derived macrophages (BMDMs) senses tumor-derived lactate and mediates lactate-induced M2 polarization. To strengthen our study of the role of Olfr78 as a lactate sensor on macrophages, we used Olfr78^−/− mice. We also sought to identify factors in tumor-conditioned media (TCM) that are sensed by Olfr78 and found that lactate and, under some conditions, acetate in TCM were the main factors involved in Olfr78-mediated generation of protumoral M2-TAMs. Furthermore, we showed that Olfr78 formed a heterodimer with Gpr132 to enhance its surface expression and mediated the lactate-induced M2 phenotype of TAMs. Finally, we demonstrated that Olfr78 deficiency inhibited tumor progression and metastasis and favored antitumor immunity in vivo. Based on our results, we propose that the Olfr78–lactate interaction plays a key role in tumor progression and thus targeting the Olfr78–lactate axis is a promising approach for targeted cancer therapy.     

Microglia–Neuron Communication in Epilepsy

Epilepsy has remained a significant social concern and financial burden globally. Current therapeutic strategies are based primarily on neurocentric mechanisms that have not proven successful in at least a third of patients, raising the need for novel alternative and complementary approaches. Recent evidence implicates glial cells and neuroinflammation in the pathogenesis of epilepsy with the promise of targeting these cells to complement existing strategies. Specifically, microglial involvement, as a major inflammatory cell in the epileptic brain, has been poorly studied. In this review, we highlight microglial reaction to experimental seizures, discuss microglial control of neuronal activities, and propose the functions of microglia during acute epileptic phenotypes, delayed neurodegeneration, and aberrant neurogenesis. Future research that would help fill in the current gaps in our knowledge includes epilepsy‐induced alterations in basic microglial functions, neuro–microglial interactions during chronic epilepsy, and microglial contribution to developmental seizures. Studying the role of microglia in epilepsy could inform therapies to better alleviate the disease. GLIA 2016;65:5–18     

The Flavonoid Quercetin Modulates the Hallmark Capabilities of Hamster Buccal Pouch Tumors

Epidemiological studies have consistently demonstrated the protective effects of dietary phytochemicals against cancer risk. Quercetin, a ubiquitous dietary flavonoid, has attracted considerable attention owing to its potent antioxidant and antiproliferative activities. The present study was designed to investigate the chemopreventive as well as the therapeutic ability of quercetin to modulate the key hallmark capabilities of 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinomas. We analyzed the expression of markers associated with cell proliferation and survival (PCNA, p21, p53, cyclin D1, GST-P), apoptosis (Fas, Fas-L, Bcl-2 family proteins, cytochrome-C, Apaf-1, caspases, PARP, survivin, cFLIP, API1), invasion (MMPs, TIMP-2, RECK), angiogenesis (PlGF, VEGF, VEGF receptors, HIF-1α), as well as the epigenetic markers (HDAC-1, DNMT1) by immunohistochemical, Western blot, and RT-PCR analyses. Simultaneous administration of quercetin to DMBA-painted hamsters reduced tumor incidence and tumor burden, while posttreatment of quercetin resulted in a significant tumor growth delay. In addition, quercetin administration induced cell cycle arrest and apoptosis and blocked invasion and angiogenesis. We found a positive correlation between the inhibition of HDAC-1 and DNMT1 by quercetin and its anticancer properties. A dietary phytochemical such as quercetin that modulates a plethora of molecules offers promise as an ideal candidate for multitargeted cancer prevention and therapy.     

Syphilitic juxta-articular nodes: case report.

Multiple juxta-articular nodes occurring in usual and unusual sites in a patient with late syphilis are described.     

Synthesis of silver nanoparticles using leaves of Catharanthus roseus Linn. G. Don and their antiplasmodial activities

Objective

To develop a novel approach for the green synthesis of silver nanoparticles using aqueous leaves extracts of Catharanthus roseus (C. roseus) Linn. G. Don which has been proven active against malaria parasite Plasmodium falciparum (P. falciparum).

Methods

Characterizations were determined by using ultraviolet-visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction.

Results

SEM showed the formation of silver nanoparticles with an average size of 35–55 nm. X-ray diffraction analysis showed that the particles were crystalline in nature with face centred cubic structure of the bulk silver with the broad peaks at 32.4, 46.4 and 28.0.

Conclusions

It can be concluded that the leaves of C. roseus can be good source for synthesis of silver nanoparticle which shows antiplasmodial activity against P. falciparum. The important outcome of the study will be the development of value added products from medicinal plants C. roseus for biomedical and nanotechnology based industries.