Biomarkers to predict response to sunitinib therapy and prognosis in metastatic renal cell cancer

Sunitinib is an orally-administered, multitargeted tyrosine kinase inhibitor. The main targets are vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, VEGFR-3, platelet-derived growth factor receptor (PDGFR)-α, and PDGFR-β. Among therapeutic targeting agents, it is the best available in the USA for patients with metastatic renal cell cancer (RCC). Well-constructed clinical trials have led to the worldwide approval of various agents for RCC. However, in clinical practice, it remains difficult to determine the best treatment strategy with these agents. Therefore, the identification of biomarkers to predict response and side-effects and to select optimal dosages is urgently needed. Potential mechanisms of action and resistance need to be understood in order to make accurate predictions. This article briefly reviews candidate biomarkers of sunitinib therapy in terms of clinical variables, genetic factors, and circulating proteins and endothelial cells. Although further validation and implementation is necessary, if validated, biomarkers will help measure the therapeutic response in individual patients and establish treatment strategies for metastatic RCC.     

Use of synchrotron-based diffraction-enhanced imaging for visualization of soft tissues in invertebrates

Images of terrestrial and marine invertebrates (snails and bivalves) have been obtained by using an X-ray phase-contrast imaging technique, namely, synchrotron-based diffraction-enhanced imaging. Synchrotron X-rays of 20, 30 and 40 keV were used, which penetrate deep enough into animal soft tissues. The phase of X-ray photons shifts slightly as they traverse an object, such as animal soft tissue, and interact with its atoms. Biological features, such as shell morphology and animal physiology, have been visualized. The contrast of the images obtained at 40 keV is the best. This optimum energy provided a clear view of the internal structural organization of the soft tissue with better contrast. The contrast is higher at edges of internal soft-tissue structures. The image improvements achieved with the diffraction-enhanced imaging technique are due to extinction, i.e., elimination of ultra-small-angle scattering. They enabled us to identify a few embedded internal shell features, such as the origin of the apex, which is the firmly attached region of the soft tissue connecting the umbilicus to the external morphology. Diffraction-enhanced imaging can provide high-quality images of soft tissues valuable for biology.     

Histotopographical study of human periocular elastic fibers using aldehyde-fuchsin staining with special reference to the sleeve and pulley system for extraocular rectus muscles

The aim of this study was to investigate the detailed configuration of periocular elastic fibers. Semiserial paraffin sections were made using 40 whole orbital contents from 27 elderly cadavers and stained by the aldehyde-fuchsin method. Periocular tissues were classified into three types according to directions of the elastic fibers, i.e., tissues containing anteroposteriorly running elastic fibers, those with mediolateral fibers, and those with meshwork of fibers. Anteroposterior elastic fiber-dominant tissue was seen in the upper eyelid and newly defined pulley plate for the medial and lateral recti (MR, LR). Mediolateral fibers were predominant in the central part of the inferior rectus pulley. In the pulley plates for the MR and LR, anteroposteriorly running fibers encased the striated muscle. Tenon’s capsule and the epimysium of the recti were mediolateral fiber-dominant. However, at the entrance of the muscle terminal where Tenon’s capsule reflects and continues to the epimysium, composite elastic fibers provided a meshwork-like skeleton. The elastic mesh was also seen around the lacrimal canaliculi. The pulley for the recti seemed to be composed of two parts—a connective tissue plate encasing the recti and specialized Tenon’s capsule at an entrance or porta of the muscle. For both parts, elastic fibers were major functional components. The anteroposterior elastic fibers in the MR and LR pulley plates, especially, seemed to receive anteroposteriorly directed stress and tension from these striated muscles. The elastic interfaces seemed to prevent any concentration of stress that would interfere with periocular striated muscle functions, including hypothetical active pulleys.     

Development of the mouse amygdala as revealed by enhanced green fluorescent protein gene transfer by means of in utero electroporation

The amygdala is located in the caudal part of the ventral telencephalon. It is composed of many subdivisions and is involved in the control of emotion. It is important to know the mechanisms of amygdalar development in order to analyze the pathogenesis of emotional disorders, but they are still not adequately understood. In the present study the migration, differentiation, and distribution of amygdalar neurons in the mouse embryo were investigated by means of in utero electroporation. Ventricular zone cells in restricted regions, that is, the caudal ganglionic eminence (CGE), the ventral pallium, the lateral pallium, and the diencephalon, were labeled with an expression vector of the enhanced green fluorescent protein (EGFP) gene. Labeling at embryonic day (E)10 revealed that the central nucleus originates from the neuroepithelium in the ganglionic eminence and the labeling at E11 and E12 revealed that the basolateral complex originates from the neuroepithelium of the ventral and lateral pallia. The introduction of the EGFP gene into the neuroepithelium of the third ventricle at E11 showed that the medial nucleus originates, at least in part, from the neuroepithelium of the diencephalon and migrates over the diencephalo–telencephalic boundary. The radial glial arrangement corresponded well with the initial migration of amygdalar neurons, and the radial processes later formed the boundary demarcating the basolateral complex. These findings indicate that the neurons originating from the temporally and spatially restricted neuroepithelium in both the telencephalon and diencephalon migrate and differentiate to form the mosaic of amygdalar subdivisions. J. Comp. Neurol. 513:113–128, 2009. © 2008 Wiley‐Liss, Inc.     

Age at onset influences on wide-ranged clinical features of sporadic amyotrophic lateral sclerosis

PurposeTo profile the detailed clinical features of sporadic amyotrophic lateral sclerosis (ALS) on large-scale samples in Japan.MethodsWe assessed the clinical features of sporadic ALS patients in Japan, based on the nationwide registration system of the Ministry of Health, Labor and Welfare of Japan. We described 3428 new cases registered cases between 2003 and 2006 to analyze initial symptoms and related clinical features, 4202 cases registered in the single year of 2005 to describe the cross-sectional overview of the ALS patients, and a total of 2128 cases with tracheostomy positive pressure ventilation (TPPV) from all of the registration data from 2003 to 2006 to describe the features of ALS patients with TPPV.ResultsThe patients with an older age at onset progressed more rapidly to the TPPV stage than those with a younger age at onset. The subpopulation of patients with long-standing TPPV showed ophthalmoplegia, while its appearance rate was less in the patients with an older age at onset than in those with a younger age at onset. Furthermore, age at onset strongly influenced the frequency of initial symptoms: dysarthria, dysphagia, neck weakness and respiratory disturbance were more frequent in patients with an older age at onset, while upper or lower limb weakness was observed more frequently in patients with a younger age at onset. In addition, those initial symptoms were still the most prominent at the follow-up stage, suggesting that the initial symptoms determine the major clinical features even in advanced illness.ConclusionsOur present study demonstrated that symptomatic features of ALS are strongly influenced by the age at onset by the large scale of samples.     

The Alzheimer's disease drug memantine increases the number of radial glia‐like progenitor cells in adult hippocampus

New neurons are continuously generated in the hippocampus of the adult mammalian brain, and N‐methyl‐D ‐aspartate receptor (NMDA‐R) antagonists have been found to increase the number of newly generated neurons in the dentate gyrus (DG) of the adult hippocampus. In this study, we examined the effect of memantine, an NMDA‐R antagonist that is clinically used for the treatment of Alzheimer's disease, on primary progenitor cells exhibiting a radial glia‐like (RGL) morphology in the DG. We injected 3‐month‐old mice with memantine (50 mg/kg body weight, intraperitoneally [i.p.]); 3 days later, we injected the mice with 5‐bromo‐2‐deoxyuridine (BrdU; 75 mg/kg body weight, i.p.). We then counted the number of BrdU‐labeled RGL progenitor cells in the DG 1 or 7 days after the BrdU‐injection. The number of BrdU‐labeled RGL progenitor cells had increased significantly by 5.1‐fold on day 1 and by 13.7‐fold on day 7 after BrdU‐injection. Immunohistochemical staining revealed that the BrdU‐labeled RGL progenitor cells expressed two primary progenitor cell marker proteins, nestin and Sox2. These results clearly demonstrated that memantine promotes the proliferation of RGL progenitor cells. We also found that memantine increased the ratio of horizontally aligned RGL progenitor cells, which are probably produced by symmetric division. These findings suggest that memantine increases the proliferation of primary progenitor cells and expands the primary progenitor cell pool in the adult hippocampus by stimulating symmetric division. © 2008 Wiley‐Liss, Inc.     

Transient Activation of Wnt/β-Catenin Signaling Induces Abnormal Growth Plate Closure and Articular Cartilage Thickening in Postnatal Mice

Wnt/β-catenin signaling is required for skeletal development and organization and for function of the growth plate and articular cartilage. To further clarify these roles and their possible pathophysiological importance, we created a new transgenic mouse model in which Wnt/β-catenin signaling can be activated in cartilage for specific periods of time. These transgenic mice expressed a constitutive active form of β-catenin fused to a modified estrogen receptor ligand-binding domain under the control of cartilage-specific collagen 11α2 promoter/enhancer. Transient Wnt/β-catenin signaling activation in young adult mice by tamoxifen injections induced growth retardation and severe deformities in knee joints. Tibial and femoral growth plates displayed an excessive number of apoptotic cells and eventually underwent abnormal regression. Articular cartilage exhibited an initial acute loss of proteoglycan matrix that was followed by increases in thickness, cell density, and cell proliferation. In reciprocal studies, we found that conditional ablation of β-catenin in postnatal mice using a Col2-CreER strategy led to hypocellularity in articular cartilage, growth plate disorganization, and a severe reduction in bone volume. Together, these data provide evidence that Wnt/β-catenin signaling has important and distinct roles in growth plate and articular cartilage and that postnatal dysregulation of this signaling pathway causes diverse structural and functional changes in the two cartilaginous structures.The Wnt/β-catenin signaling pathway plays essential roles in animal development, determination of cell lineages, and progression of cell differentiation.^1,2,3 Previous studies from this and other groups established that this pathway regulates skeletal development and growth and influences skeletal cell behavior.^4,5,6,7,8,9 Conditional ablation of β-catenin in mouse embryo cartilage was found to cause alterations in growth plate chondrocyte function in developing skeletal elements; the cells exhibited a delay in hypertrophy and consequently both endochondral bone formation and skeletal growth were significantly disturbed.^4,5,6,7 Recent studies showed that reduction of Wnt/β-catenin signaling is deleterious for not only growth plate but also articular cartilage^10,11 and that constitutive activation of Wnt/β-catenin signaling in cartilage leads to skeletal deformities and disruption of joint structures.^4,8,12 These and other studies have provided strong support for the conclusion that Wnt/β-catenin signaling must be kept under strict control during skeletal development and growth and that inhibition or hyperactivity of this pathway is incompatible with normal skeletal function and homeostasis and could lead to pathological conditions.In vivo and in vitro studies have indicated that Wnt/β-catenin signaling affects multiple pathways and mechanisms in the chondrocytes. We found that acute experimental activation of Wnt/β-catenin signaling strongly stimulates matrix catabolism and protease activity^8,13 and promotes expression of phenotypic traits associated with chondrocyte hypertrophy and replacement with endochondral bone.⁹ Others showed that Wnt/β-catenin signaling affects chondrocyte survival^10,11 and stimulates proliferation.¹⁴ It has remained unclear, however, whether and how these and other cellular changes caused by overactivation or inhibition of Wnt/β-catenin signaling relate to and bring about malfunction and deformities in growth plate and articular cartilage, particularly those associated with aging or skeletal pathological changes. To approach these important issues and questions, we created a new transgenic mouse model in which Wnt/β-catenin signaling can be activated in cartilage at specific time points and specific lengths of time prenatally or postnatally. We used a construct encoding a constitutive-active form of β-catenin fused to a modified estrogen receptor ligand-binding domain (CA-β-catER) that was previously used to create transgenic mice in which Wnt/β-catenin signaling was activated in keratinocytes after tamoxifen injection.¹⁵ Our data indicate that transient activation of Wnt/β-catenin signaling in cartilage in postnatal mice induces rapid and excessive apoptosis in growth plate chondrocytes and irreversible regression of growth plates. The mice also displayed defects in articular cartilage that included rapid proteoglycan loss followed by increases in tissue thickness and cell density. These data suggest that both growth plate and articular cartilage are affected by acute overactivation of Wnt/β-catenin signaling, but their responses are distinct and may have distinct pathological implications.     

Molecular and functional characteristics of proton-coupled folate transporter

Proton-coupled folate transporter (PCFT) has recently been identified as the molecular entity of the carrier-mediated intestinal folate transport system. PCFT has been demonstrated to be most abundantly expressed in the upper small intestine, localizing at the brush border membrane of epithelial cells, transport folate and its analogs more efficiently at lower (acidic) pH by a H(+)-coupled cotransport mechanism, and have a high affinity for folate with a Michaelis constant (K(m)) of a few microM at pH 5.5 and somewhat lower affinities for reduced folates and methotrexate (MTX). A loss of PCFT function due to a homozygous mutation in its gene has been indicated to be responsible for hereditary folate malabsorption. Thus, PCFT has all the characteristics of the brush border H(+)-coupled cotransporter for folate and analogs, which has long been suggested to be present in the intestine. Furthermore, sulfasalazine was found to be a potent inhibitor of PCFT, suggesting that it is a risk factor that would cause malabsorption of folate and also MTX, when coadministered in the treatment of rheumatoid arthritis. Understanding the molecular and functional characteristics of PCFT should be important and helpful in exploring therapeutic strategies for folate malabsorption and in optimizing therapies using antifolate drugs.