Endothelial Cells Provide a Notch-Dependent Pro-Tumoral Niche for Enhancing Breast Cancer Survival,Stemness and Pro-Metastatic Properties

Treating metastasis has been challenging due to tumors complexity and heterogeneity. This complexity is partly related to the crosstalk between tumor and its microenvironment. Endothelial cells -the building blocks of tumor vasculature- have been shown to have additional roles in cancer progression than angiogenesis and supplying oxygen and nutrients. Here, we show an alternative role for endothelial cells in supporting breast cancer growth and spreading independent of their vascular functions. Using endothelial cells and breast cancer cell lines MDA-MB231 and MCF-7, we developed co-culture systems to study the influence of tumor endothelium on breast tumor development by both in vitro and in vivo approaches. Our results demonstrated that endothelial cells conferred survival advantage to tumor cells under complete starvation and enriched the CD44^HighCD24^Low/- stem cell population in tumor cells. Moreover, endothelial cells enhanced the pro-metastatic potential of breast cancer cells. The in vitro and in vivo results concordantly confirmed a role for endothelial Jagged1 to promote breast tumor through notch activation. Here, we propose a role for endothelial cells in enhancing breast cancer progression, stemness, and pro-metastatic traits through a perfusion-independent manner. Our findings may be beneficial in developing novel therapeutic approaches.     

Polyelectrolyte Effects on 9-Aminoacridine-DNA Binding

Abstract

The 9-aminoacridine-DNA binding curve is analyzed in two ways: with polyelectrolyte effects neglected and with polyelectrolyte effects included. It is found that the analysis which includes polyelectrolyte effects is consistent with the violation of neighbor exclusion displayed by diacridine complexes as observed by Atwell et al. and by Zimmerman and coworkers. However the analysis which neglects polyelectrolyte effects is inconsistent with the diacridine results. This comparison supports the necessity of including polyelectrolyte effects in the analysis of drug-DNA binding curves.     

Trichome micromorphology of Iranian Stachys (Lamiaceae) with emphasis on its systematic implication

Trichomes of 37 taxa of the genus Stachys and one species of Sideritis (S. montana) were examined using light and scanning electron microscopy. The indumentum shows considerable variability among different species, but is constant among different populations of one species, and therefore, affords valuable characters in delimitation of sections and species. The characters of taxonomic interest were presence of glandular and non-glandular trichomes, thickness of the cell walls, number of cells (unicellular or multi-cellular), presence of branched (dendroid) trichomes, presence of vermiform trichomes, orientation of trichomes in relation to the epidermal surface, curviness of trichomes, and presence of papillae on trichome surface. Two basic types of trichomes can be distinguished: glandular and non-glandular trichomes. The glandular trichomes can in turn be subdivided into subtypes: stalked, subsessile, or sessile. The stalks of the glandular trichomes can be uni- or multi-cellular. Simple unbranched and branched trichomes constitute two subtypes of non-glandular trichomes. Our data do not provide any support for separation of Sideritis from Stachys. The following evolutionary trends are suggested here for Stachys: vermiform trichomes with stellate base are primitive against vermiform trichomes with tuberculate base, long vermiform trichomes are primitive against the short simple trichomes, appressed trichomes are advanced against spreading ones, and loss of glandular trichomes is advanced against their presence. Overall, trichome micromorphology is more useful in separation of species within sections rather than characterizing large natural groups known as sections, except for few cases.     

Suppression of Tumor Angiogenesis by G��13 Haploinsufficiency

Heterotrimeric G proteins are critical transducers of cellular signaling. Of the four families of G proteins, the physiological function of Gα₁₃ is less well understood. Gα₁₃ gene-deleted mice die at embryonic day ∼9.5. Here, we show that heterozygous Gα₁₃^+/− mice display defects in adult angiogenesis. Female Gα₁₃^+/− mice showed a higher number of immature follicles and a lower density of blood vessels in the mature corpus luteum compared with Gα₁₃^+/+ mice. Furthermore, implanted tumors grew slower in Gα₁₃^+/− host mice. These tumor tissues had many fewer blood vessels compared with those from Gα₁₃^+/+ host mice. Moreover, bone marrow-derived progenitor cells from Gα₁₃^+/+ mice rescued the failed growth of allografted tumors when reconstituted into irradiated Gα₁₃^+/− mice. Hence, Gα₁₃ is haploinsufficient for adult angiogenesis in both the female reproductive system and tumor angiogenesis.A structurally diverse repertoire of ligands, from photons to large peptides, activates G protein-coupled receptors to elicit their physiological functions (1). In turn, ligand-bound G protein-coupled receptors function as guanine nucleotide exchange factors, catalyzing the exchange of GDP bound on the Gα subunit with GTP in the presence of Gβγ and causing the dissociation of the Gα subunit from the Gβγ dimer to form two functional units (Gα and Gβγ) (2). Both Gα and Gβγ subunits signal to various cellular pathways. Based on sequence and functional homologies, G proteins are grouped into four families: G_s, G_i, G_q, and G₁₂ (3). Of these four subfamilies of G proteins, the physiological function of the G₁₂ subfamily is less well understood. In this family, there are two members, G₁₂ and G₁₃. Gα₁₂ knock-out mice appear normal (4). Gα₁₃ knock-out mice display embryonic lethality (embryonic day ∼9.5) (5). Gα₁₃^−/− mouse embryos have defective vascular systems (5). Endothelial cell-specific deletion of Gα₁₃ also results in vascular defect and embryonic lethality (6). The molecular basis that underlies the vascular defect observed in Gα₁₃^−/− mouse embryos has not been defined.Angiogenesis (formation of endothelium-lined blood vessels) is essential for organ growth in the embryo and for repair of wounded tissues in the adult (7, 8). An imbalance in angiogenesis contributes to the pathogenesis of numerous malignant, inflammatory, ischemic, infectious, and immune disorders and cancers (7, 8). Most angiogenesis events take place during embryonic development. In adult tissues, the majority of endothelial cells are quiescent, and angiogenesis occurs only rarely except in a few adult tissues (including ovary) that exhibit periodic and dynamic growth and regression (9–11). Under pathological conditions such as tumor growth, adult angiogenesis is induced. Tumor angiogenesis is the proliferation of a network of blood vessels that penetrates into cancerous growths (including implanted tumor tissues), supplying nutrients and oxygen and removing waste products. Solid tumors depend on angiogenesis for growth and metastasis in a hostile environment (12). Bone marrow is the origin of endothelial progenitor cells in the adult. Bone marrow-derived endothelial progenitor cells are mobilized into peripheral blood and recruited to the foci of pathophysiological neovascularization and re-endothelialization, thereby contributing to vascular regeneration (13). Vascular endothelial growth factor (VEGF),² the most critical factor for angiogenesis, is an important factor for the mobilization of endothelial progenitor cells from bone marrow (7, 8). Bone marrow transplantation experiments have demonstrated the incorporation of bone marrow-derived endothelial progenitor cells into foci of pathological neovascularization such as growing tumors, healing wounds, ischemic skeletal and cardiac muscles, and cornea receiving micropocket surgery (14–21).Here, we show that heterozygous Gα₁₃^+/− mice display defects in adult angiogenesis. We found that female Gα₁₃^+/− mice show a higher number of immature follicles and a lower density of blood vessels in the mature corpus luteum compared with Gα₁₃^+/+ mice. Furthermore, implanted tumors grew slower in Gα₁₃^+/− host mice. These tumor tissues had many fewer blood vessels compared with those from Gα₁₃^+/+ host mice. We also down-regulated Gα₁₃ in endothelial cells by RNA interference and show that defective migration and tube formation in response to VEGF likely contribute to the impaired angiogenesis. Moreover, bone marrow-derived cells from Gα₁₃^+/+ mice rescued the failed growth of allografted tumors when reconstituted into irradiated Gα₁₃^+/− mice. Our results demonstrate that Gα₁₃ is haploinsufficient for adult angiogenesis in both the female reproductive system and tumor angiogenesis. This role in adult angiogenesis provides a suitable system to further investigate the biochemical and physiological functions of Gα₁₃. Moreover, Gα₁₃ inhibition could be explored for anticancer drug development.     

突尼斯非洲跳鼠（Jaculus jaculus）和埃及跳鼠J.orientalis）群体的等位酶多态及遗传分化

运用16种酶蛋白编码的23个遗传座位对突尼斯非洲跳鼠(Jaculus jaculus)和埃及跳鼠(J.orientalis)自然群体的遗传变异和分化进行了电泳分析.结果表明,与其他啮齿动物等哺乳动物的相关数据比较,发现这两个种群体的遗传变异水平较低.非洲跳鼠群体的观测杂合度(Hobs)为0.08-0.19,多态座位百分比(P)为26.2%-45.2%,每个座何的平均等位基因数(A)为1.1-1.4;埃及跳鼠的Hobs为0.10-0.15,P为29.3%-44.1%,A为1.1-1.7.两个种群体各自的遗传分化程度较低(非洲跳鼠和埃及跳鼠的Fst分别为0.0017和0.0019).而两个种群体间的Fst为0.607(P＜0.05),表明两个种之间高度的遗传分化.本研究支持这两个种分类地位的合法性,并强调了地理因素(环境类犁和生物气候阶段)对两个种遗传结构的影响.     

Low cytotoxicity effect of dendrosome as an efficient carrier for rotavirus <Emphasis Type="Italic">VP2</Emphasis> gene transferring into a human lung cell line

The efficiency of dendrosome (a gene porter) was assessed in transferring recombinant human rotavirus VP2 cDNA into A549, a human lung cell line. After gene transferring, transmission electron microscopy showed core-like particles (CLPs) formation in the transfected cells both with dendrosome and lipofectamine porters. In addition, western blotting analysis showed that the expression of VP2 gene was almost equal in the dendrosome and lipofectamine-transfected cells. Also, the cytotoxicity studies revealed that dendrosome had a lower cytotoxicity than lipofectamine. Therefore, our study may introduce dendrosome as a possible carrier for gene transferring into the human lung cell line, especially, for intranasally administration of DNA vaccines.     

Life history variation in a temperate plant invader, <Emphasis Type="Italic">Verbascum thapsus</Emphasis> along a tropical elevational gradient in Hawaii

Few studies have examined the life history of temperate plant invaders in the tropics. Temperate invaders that utilize seasonal cues to influence their life histories may be expected to behave differently in the tropics. This study examined variation in life history in an invading temperate weed, Verbascum thapsus, across an elevation gradient (1,690–2,720 m) along the montane and subalpine slopes of Mauna Kea, Hawaii. Over 7,000 seedlings were marked and monitored over a period of 3 years. Germination, survival, growth, and reproduction in V. thapsus varied among sites along the elevational gradient. Compared to plants at lower elevations, those at higher elevation sites (>2,000 m) had lower early seedling survival, higher established rosette survival, higher vegetative growth rates, higher threshold sizes for flowering, and commonly lived more than 3 years before flowering. The abundance of competing vegetation generally decreased with elevation, and this may drive variation in V. thapsus survival and growth. Size-dependent survival appears to play a major role in the selection for smaller size at first flowering and shorter generation time at lower elevations. This pattern is opposite to that reported in temperate mountains where high elevation plants flower sooner and at smaller size, but both patterns appear consistent with general life history theory for biennials. Due to novel biotic and climatic interactions in the tropics, predictions of growth patterns and invasion dynamics for temperate weeds in the tropics can be misleading when based on the plant’s behavior in temperate systems.     

Cytotoxic T cells expressing the co-stimulatory receptor NKG2 D are increased in cigarette smoking and COPD

Background

A suggested role for T cells in COPD pathogenesis is based on associations between increased lung cytotoxic T lymphocyte (CD8⁺) numbers and airflow limitation. CD69 is an early T cell activation marker. Natural Killer cell group 2 D (NKG2D) receptors are co-stimulatory molecules induced on CD8⁺ T cells upon activation. The activating function of NKG2 D is triggered by binding to MHC class 1 chain-related (MIC) molecules A and B, expressed on surface of stressed epithelial cells. The aim of this study was to evaluate the expression of MIC A and B in the bronchial epithelium and NKG2 D and CD69 on BAL lymphocytes in subjects with COPD, compared to smokers with normal lung function and healthy never-smokers.

Methods

Bronchoscopy with airway lavages and endobronchial mucosal biopsy sampling was performed in 35 patients with COPD, 21 healthy never-smokers and 16 smokers with normal lung function. Biopsies were immunohistochemically stained and BAL lymphocyte subsets were determined using flow cytometry.

Results

Epithelial CD3⁺ lymphocytes in bronchial biopsies were increased in both smokers with normal lung function and in COPD patients, compared to never-smokers. Epithelial CD8⁺ lymphocyte numbers were higher in the COPD group compared to never-smoking controls. Among gated CD3⁺cells in BAL, the percentage of CD8⁺ NKG2D⁺ cells was enhanced in patients with COPD and smokers with normal lung function, compared to never-smokers. The percentage of CD8⁺ CD69⁺ cells and cell surface expression of CD69 were enhanced in patients with COPD and smokers with normal lung function, compared to never-smokers. No changes in the expression of MIC A or MIC B in the airway epithelium could be detected between the groups, whereas significantly decreased soluble MICB was detected in bronchial wash from smokers with normal lung function, compared to never-smokers.

Conclusions

In COPD, we found increased numbers of cytotoxic T cells in both bronchial epithelium and airway lumen. Further, the proportions of CD69- and NKG2D-expressing cytotoxic T cells in BAL fluid were enhanced in both subjects with COPD and smokers with normal lung function and increased expression of CD69 was found on CD8⁺ cells, indicating the cigarette smoke exposure-induced expansion of activated cytotoxic T cells, which potentially can respond to stressed epithelial cells.