Spheroidal Population Research Articles

Analysis of Cancer Cell Invasion and Anti-metastatic Drug Screening Using Hydrogel Micro-chamber Array (HMCA)-based Plates.

Cancer metastasis is known to cause 90% of cancer lethality. Metastasis is a multistage process which initiates with the penetration/invasion of tumor cells into neighboring tissue. Thus, invasion is a crucial step in metastasis, making the invasion process research and development of anti-metastatic drugs, highly significant. To address this demand, there is a need to develop 3D in vitro models which imitate the architecture of solid tumors and their microenvironment most closely to in vivo state on one hand, but at the same time be reproducible, robust and suitable for high yield and high content measurements. Currently, most invasion assays lean on sophisticated microfluidic technologies which are adequate for research but not for high volume drug screening. Other assays using plate-based devices with isolated individual spheroids in each well are material consuming and have low sample size per condition. The goal of the current protocol is to provide a simple and reproducible biomimetic 3D cell-based system for the analysis of invasion capacity in large populations of tumor spheroids. We developed a 3D model for invasion assay based on HMCA imaging plate for the research of tumor invasion and anti-metastatic drug discovery. This device enables the production of numerous uniform spheroids per well (high sample size per condition) surrounded by ECM components, while continuously and simultaneously observing and measuring the spheroids at single-element resolution for medium throughput screening of anti-metastatic drugs. This platform is presented here by the production of HeLa and MCF7 spheroids for exemplifying single cell and collective invasion. We compare the influence of the ECM component hyaluronic acid (HA) on the invasive capacity of collagen surrounding HeLa spheroids. Finally, we introduce Fisetin (invasion inhibitor) to HeLa spheroids and nitric oxide (NO) (invasion activator) to MCF7 spheroids. The results are analyzed by in-house software which enables semi-automatic, simple and fast analysis which facilitates multi-parameter examination.

No evidence for small disk-like bulges in a sample of late-type spirals

About 20% of low-redshift galaxies are late-type spirals with a small or no bulge component. Although they are the simplest disk galaxies in terms of structure and dynamics, the role of the different physical processes driving their formation and evolution is not yet fully understood. We investigated whether small bulges of late-type spirals follow the same scaling relations traced by ellipticals and large bulges and if they are disk-like or classical bulges. We derived the photometric and kinematic properties of 9 nearby late-type spirals. To this aim, we analyzed the surface brightness distribution from the i-band images of the Sloan Digital Sky Survey and obtained the structural parameters of the galaxies from a two-dimensional photometric decomposition. We measured the line-of-sight stellar velocity distribution within the bulge effective radius from the long-slit spectra taken with high spectral resolution at the Telescopio Nazionale Galileo. We used the photometric and kinematic properties of the sample bulges to study their location in the Fundamental Plane, Kormendy, and Faber-Jackson relations defined for ellipticals and large bulges. We found that our sample bulges satisfy some of the photometric and kinematic prescriptions for being considered disk-like bulges such as small sizes and masses with nearly exponential light profiles, small bulge-to-total luminosity ratios, low stellar velocity dispersions, and ongoing star formation. However, each of them follows the same scaling relations of ellipticals, massive bulges, and compact early-type galaxies so they cannot be classified as disk-like systems. We find a single population of galaxy spheroids that follow the same scaling relations, where the mass seems to lead to a smooth transition in the photometric and kinematic properties from less massive bulges to more massive bulges and ellipticals.

Observations of Lyα and O vi: Signatures of Cooling and Star Formation in a Massive Central Cluster Galaxy

Abstract We report new Hubble Space Telescope COS and Space Telescope Imaging Spectrograph spectroscopy of a star-forming region ( yr−1) in the center of the X-ray cluster RX J1532.9+3021 (z = 0.362), to follow-up the CLASH team discovery of luminous UV filaments and knots in the central massive galaxy. We detect broad (∼500 km s−1) Lyα emission lines with extraordinarily high equivalent widths (EQW ∼ 200 Å) and somewhat less broadened Hα (∼220 km s−1). Ultraviolet emission lines of N v and O vi are not detected, which constrains the rate at which gas cools through temperatures of 106 K to be ≲10 M ⊙ yr−1. The COS spectra also show a flat rest-frame UV continuum with weak stellar photospheric features, consistent with the presence of recently formed hot stars forming at a rate of ∼10 M ⊙ yr−1, uncorrected for dust extinction. The slope and absorption lines in these UV spectra are similar to those of Lyman Break Galaxies at , albeit those with the highest Lyα equivalent widths and star formation rates. This high-EQW Lyα source is a high-metallicity galaxy rapidly forming stars in structures that look nothing like disks. This mode of star formation could significantly contribute to the spheroidal population of galaxies. The constraint on the luminosity of any O vi line emission is stringent enough to rule out steady and simultaneous gas cooling and star formation, unlike similar systems in the Phoenix Cluster and Abell 1795. The fact that the current star formation rate differs from the local mass cooling rate is consistent with recent simulations of episodic active galactic nucleus feedback and star formation in a cluster atmosphere.

A process engineering approach to increase organoid yield.

Temporal manipulation of the in vitro environment and growth factors can direct differentiation of human pluripotent stem cells into organoids - aggregates with multiple tissue-specific cell types and three-dimensional structure mimicking native organs. A mechanistic understanding of early organoid formation is essential for improving the robustness of these methods, which is necessary prior to use in drug development and regenerative medicine. We investigated intestinal organoid emergence, focusing on measurable parameters of hindgut spheroids, the intermediate step between definitive endoderm and mature organoids. We found that 13% of spheroids were pre-organoids that matured into intestinal organoids. Spheroids varied by several structural parameters: cell number, diameter and morphology. Hypothesizing that diameter and the morphological feature of an inner mass were key parameters for spheroid maturation, we sorted spheroids using an automated micropipette aspiration and release system and monitored the cultures for organoid formation. We discovered that populations of spheroids with a diameter greater than 75 μm and an inner mass are enriched 1.5- and 3.8-fold for pre-organoids, respectively, thus providing rational guidelines towards establishing a robust protocol for high quality intestinal organoids.

Abstract C40: Pancreatic cancer and stroma cell cross-talk affects cell proliferation in a 3D spheroid co-culture model

Abstract Aim of the study: The aim of this study was to validate a novel 3D spheroid co-culture model of pancreatic ductal adenocarcinoma (PDAC) cells and pancreatic stellate cells (PSCs), and to use said model as to investigate the effects of PDAC cell and PSC cross-talk on cell proliferation, cell death, migration and chemo-resistance. Methods: An eGFP-positive PSC line and PDAC cell lines were cultured in 3D spheroid mono- and co-cultures. Activation of the PSCs within the co-culture model was investigated by real time PCR for whole spheroids and spheroid populations sorted by fluorescence activated cell sorting (FACS). To investigate cell proliferation the cell numbers within the cultures were followed over time and the proportions of the different cell types within the co-cultures were monitored by FACS. Results: The mRNA expression of the PSC activation marker ASMA as well as the ECM proteins collagen I, laminin and lumican, the PDGFbeta receptor (PDGFRb) and the transforming growth factor beta1 (TGFb-1) downstream effector connective tissue growth factor (CTGF), were increased in PSCs within co-cultures compared to mono-cultures. PSCs were initially expanding but then diminished within 3D spheroid co-cultures together with two separate PDAC cell lines (Panc-1 and HPAF-II). Panc-1 cell numbers were seemingly unaffected by the presence of PSCs, but with higher proportions of PSCs the Panc1 cell numbers within the co-cultures initially were lagging behind but then caught up to the numbers within the mono-cultures. This growth switch was correlated with the opposite switch seen for the PSCs. The proliferation of HPAF-II cells, was on the other hand induced within the co-cultures compared to mono-cultures. Conclusions: PSCs are activated within the 3D spheroid co-cultures. Both tumor cell and PSC proliferation is influenced by co-culturing the cells in the 3D spheroid model. Different PDAC cell – PSC combinations are affected differently. We currently are investigating the effects on cell death and apoptosis, migration and chemo-resistance. Citation Format: Jessica K. Norberg, Salvatore Nania, Rainer L. Heuchel, Matthias J. Löhr. Pancreatic cancer and stroma cell cross-talk affects cell proliferation in a 3D spheroid co-culture model. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C40.

Abstract 278: No cell left behind: Residual ovarian spheroids drive recurrence and are sensitive to the pro-oxidant elesclomol

Abstract Sphere forming cells persist in the ascitic fluid of patients with high-grade serous ovarian cancer after first-line therapy and likely contribute to relapse and metastasis. These residual tumor spheres, which are enriched for cancer cells by up to 95% based on detectable TP53 mutations, are slow growing, resistant to platinum-based chemotherapy, and remain a large obstacle towards durable remission. Screening established, rapidly dividing monolayer cell lines in proliferation assays has failed to produce chemotherapeutics capable of eradicating this slow growing population. To identify a consolidation therapy that targets these residual tumor cells we screened nearly 2000 mechanistically annotated, approved and investigational drugs in three cell lines (PEO1, PANC1, A375M) cultured in spheroid and conventional monolayer. To elucidate targetable genes and pathways responsible for spheroid maintenance we performed a whole-genome RNAi screen against PEO1 in both culture conditions. Our pharmacological and genetic profiling provided mechanistic insight into the baseline changes that occur when cells are grown in three dimensional, anchorage independent conditions and identified susceptibilities specific to spheroid populations. Consistent with residual disease, cultured spheres were resistant to many common chemotherapeutics, most notably proteasome inhibitors, but were highly sensitive to the pro-oxidant elesclomol. We verified elesclomol's activity in ex vivo cancer spheroids extracted from the ascitic fluid of patients with advanced high-grade serous ovarian cancer using a simple, culture-free technique. Expression profiling of cultured and ex vivo spheres revealed broad downregulation of genes involved in cell cycle signaling (AURKA, AURKB, PLK1, CDK1, CCNA2, CCNB1, CCNB2, GMNN, CHEK1). Treatment with elesclomol induced expression of chaperone proteins (HSP6, HSP7, HSPA1A, HSPA1B, DNAJA4, DNAJB1), metallothionein proteins (MT1F, MT1M, MT1P2, MT1X, MT2A), and genes involved with the oxidative stress response (HMOX1, ABCB1, SLC7A11) consistent with increased reactive oxygen species caused by high intracellular Cu2+. To pursue this drug as a consolidation therapy in vivo, we evaluated elesclomol's toxicity, pharmacokinetic properties, and efficacy in a murine model for recurrent high-grade serous ovarian cancer. By targeting residual tumor cells with elesclomol after successful treatment with platinum-based therapeutics we hope to prevent recurrence. Citation Format: Ian S. Goldlust, Kelli Wilson, Ludmila Szabova, Xiaohu Zhang, Lesley Mathews-Griner, Maria Vias, Anna Piskorz, Rory Stark, Lee Mendil, Monica Kasbekar, John Braisted, Rajarshi Guha, Crystal McKnight, Paul Shinn, Donna Michelle-Smith, Zoe Weaver Ohler, Mindy Davis, Udo Rudloff, Sam Michael, Madhu Lal-Nag, Scott Martin, Christina Annunziata, Marc Ferrer, James D. Brenton, Craig Thomas. No cell left behind: Residual ovarian spheroids drive recurrence and are sensitive to the pro-oxidant elesclomol. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 278.

Abstract A15: Different stem-like characteristics of diffuse and intestinal type gastric cancer spheroids

Abstract Cancer Stem Cells (CSCs) have been hypothesized to drive the tumor initiation, metastasis and chemo-resistance. Identification of this subpopulation is important to understand the CSCs characteristics and the development of treatment strategy. Spheroid forming ability is the character of CSCs. Thus, sphere culture can be utilized for isolation of CSCs in cancer cell lines. Here, we applied Spheroid Film as a limiting dilution assay platform to isolate gastric CSCs from single cell sphere culture. Gastric cancer cell lines MKN28, MKN74, SNU484 and SNU638 was seeded as single cell in non-attached 361 micro-wells culture dish with serum free condition. After 2 weeks, each well was evaluated whether single cell formed spheroid or not. The population of spheroids was increased in sub-spheroid culture. The spheroids showed higher expression levels of stemness marker, such as OCT4, SOX2 and NANOG than parent cells. Moreover, they exhibited up-regulation of CSC related gene ALDH1A1 and CD44v8-10 compared with parent cells. Spheroids cell were more resistant to drug inducing apoptosis (5FU, Cisplatin and Paclitaxel) than parent cells. When spheroids injected in to skin of nude mice, it showed larger size of tumor than parent cells. Especially, the expression of stemness gene was higher in diffuse type (SNU484 and SNU638) than intestinal type (MKN28 and MKN74). Besides, diffuse type has lower IC50 value of anti-cancer drugs than intestinal type. In conclusion, cancer stem-like cells were isolated efficiently by single cell spheroid culture methods from gastric cancer cell lines. We have shown that different stem-like characteristics in spheroids cell, and it may be related with their histological type. Further investigation of difference between diffuse and intestinal type gastric cancer sphroids may provide novel insights to understand gastric cancer stem cells. Citation Format: Jong Won Lee, Jae Sook Sung, Seok Chung, Yeul Hong Kim. Different stem-like characteristics of diffuse and intestinal type gastric cancer spheroids. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr A15.

Hydrogel microstructure live-cell array for multiplexed analyses of cancer stem cells, tumor heterogeneity and differential drug response at single-element resolution.

Specific phenotypic subpopulations of cancer stem cells (CSCs) are responsible for tumor development, production of heterogeneous differentiated tumor mass, metastasis, and resistance to therapies. The development of therapeutic approaches based on targeting rare CSCs has been limited partially due to the lack of appropriate experimental models and measurement approaches. The current study presents new tools and methodologies based on a hydrogel microstructure array (HMA) for identification and multiplex analyses of CSCs. Low-melt agarose integrated with type I collagen, a major component of the extracellular matrix (ECM), was used to form a solid hydrogel array with natural non-adhesive characteristics and high optical quality. The array contained thousands of individual pyramidal shaped, nanoliter-volume micro-chambers (MCs), allowing concomitant generation and measurement of large populations of free-floating CSC spheroids from single cells, each in an individual micro-chamber (MC). The optical live cell platform, based on an imaging plate patterned with HMA, was validated using CSC-enriched prostate and colon cancer cell lines. The HMA methodology and quantitative image analysis at single-element resolution clearly demonstrates several levels of tumor cell heterogeneity, including morphological and phenotypic variability, differences in proliferation capacity and in drug response. Moreover, the system facilitates real-time examination of single stem cell (SC) fate, as well as drug-induced alteration in expression of stemness markers. The technology may be applicable in personalized cancer treatment, including multiplex ex vivo analysis of heterogeneous patient-derived tumor specimens, precise detection and characterization of potentially dangerous cell phenotypes, and for representative evaluation of drug sensitivity of CSCs and other types of tumor cells.

CANDELS VISUAL CLASSIFICATIONS: SCHEME, DATA RELEASE, AND FIRST RESULTS

We have undertaken an ambitious program to visually classify all galaxies in the five CANDELS fields down to H<24.5 involving the dedicated efforts of 65 individual classifiers. Once completed, we expect to have detailed morphological classifications for over 50,000 galaxies up to z<4 over all the fields. Here, we present our detailed visual classification scheme, which was designed to cover a wide range of CANDELS science goals. This scheme includes the basic Hubble sequence types, but also includes a detailed look at mergers and interactions, the clumpiness of galaxies, $k$-corrections, and a variety of other structural properties. In this paper, we focus on the first field to be completed -- GOODS-S. The wide area coverage spanning the full field includes 7634 galaxies that have been classified by at least three different people. In the deep area of the field, 2534 galaxies have been classified by at least five different people at three different depths. With this paper, we release to the public all of the visual classifications in GOODS-S along with the GUI that we developed to classify galaxies. We find that the level of agreement among classifiers is good and depends on both the galaxy magnitude and the galaxy type, with disks showing the highest level of agreement and irregulars the lowest. A comparison of our classifications with the Sersic index and rest-frame colors shows a clear separation between disk and spheroid populations. Finally, we explore morphological k-corrections between the V-band and H-band observations and find that a small fraction (84 galaxies in total) are classified as being very different between these two bands. These galaxies typically have very clumpy and extended morphology or are very faint in the V-band.

Hypoxia-mediated cancer stem cells in pseudopalisades with activation of hypoxia-inducible factor-1α/Akt axis in glioblastoma.

Pseudopalisades (Ps) around necrotic foci are severely hypoxic and overexpress hypoxia-inducible factor (HIF) in glioblastoma (GBM). Hypoxic regions have been proposed as one of several distinct niches for cancer stem cells (CSCs) in GBM, but little is known about the association between Ps features and CSC properties. Herein, we focused on the biological role of Ps lesions. In clinical cases of GBM, expression of hypoxia-related molecules including HIF-1α, Glut-1, p27(Kip1), and pAkt was significantly increased in perinecrotic Ps lesions compared with nonnecrotic areas and perinecrotic lesions lacking Ps features. Significantly higher expression levels of several CSC-related markers, including CD133, Sox2, CD44s, and aldehyde dehydrogenase (ALDH) 1, were also observed in Ps lesions, which were positively correlated with expression of hypoxia-related molecules and pAkt. Ps lesions also showed increased number of apoptotic cells and decreased bcl-2 and survivin expression compared with the surrounding tissue. Short-term exposure of astrocytoma cell lines to cobalt chloride, which is known to mimic the effect of hypoxia, caused an increase in expression of both hypoxia- and CSC-related markers, in line with increases in the ALDH(high) cell population and number of spheroids. Inhibition of endogenous Akt by LY294002 resulted in decreased expression of Sox2, ALDH1, and CD133, leading to enhancement of cobalt chloride-mediated apoptotic events due to altered ratio of bcl-2 to bax expression. These findings suggest that Ps lesions within GBM may serve as a specialized hypoxic niche, in which the HIF-1α/pAkt axis is activated, in response to severe hypoxia.

Isolation and characterization of cancer stem cells in head and neck squamous cell carcinoma

The hypothesis that a small subset of cells with characteristics of staminality is essential for the cancer onset has been widely studied in many tumors, included head-neck cancer, the seventh most common cancer in humans (1). These cells represent a small oncogenic subpopulation, with a characteristic phenotype that confers them a greater resistance to chemotherapy and radiotherapy (2). In this study the expression profile of some genes that differentiates cancer stem cells (CSC) from tumor cell of origin (TC) has been evaluated using Real Time PCR. Three cell lines, PE46, PE15 and HEP2, obtained from head and neck squamous cell carcinoma, where placed in culture, in absence of serum and in the presence of specific growth factors, giving rise to a spheroid cell subpopulation, with characteristics belonging to CSC. CSC were isolated using a selective filtration procedure based on beads labeled with the anti-CD44, that recognize a specific antigen of CSC in head and neck cancer (1). Few genes potentially involved in the onset and progression of oral cancer, were eval- uated in Real Time PCR, in order to compare their expression in CSC respect TC. All the three cell lines showed a common expression profile among the stem cell markers, resulting in an overexpression of the CD44 and ALDH1A in the spheroid population. Many of the investigated tumor markers were highly over-expressed in CSC, like TNFα, a pro-inflammatory factor that inhibits precancerous cell death, TP63, which is associated with an increase in the malignant transformation and a poor prognosis, and S100A4, a pro-inflammatory mediator involved in epithelial-mesenchymal transition of cancer cells. These results suggest the potential role of CSC in the tumor invasiveness. The characterization of CSC may lead to an improvement in the diagnosis and cancer therapy, allowing implementing treatments able to destroy cells which are probably involved in the process of metastasis.

Towards metamaterials with giant dielectric anisotropy via homogenization: An analytical study

A random mixture of two isotropic dielectric materials, one composed of oriented spheroidal particles of relative permittivity ϵa and the other composed of oriented spheroidal particles of relative permittivity ϵb, was considered in the long wavelength regime. The permittivity dyadic of the resulting homogenized composite material (HCM) was estimated using the Bruggeman homogenization formalism. The HCM was an orthorhombic biaxial material if the symmetry axes of the two populations of spheroids were mutually perpendicular and a uniaxial material if these two axes were mutually aligned. The degree of anisotropy of the HCM, as gauged by the ratio of the eigenvalues of the HCM's permittivity dyadic, increased as the shape of the constituent particles became more eccentric. The greatest degrees of HCM anisotropy were achieved for the limiting cases wherein the constituent particles were shaped as needles or discs. In these instances explicit formulas for the HCM anisotropy were derived from the dyadic Bruggeman equation. Using these formulas it was found that the degrees of HCM anisotropy are proportional to ϵb or ϵb, at fixed values of volume fraction and ϵa, for ϵb>ϵa. Thus, in principle, metamaterials can be conceptualized via homogenization with extremely large degrees of anisotropy, by controlling the geometries and orientations of remarkably simple constituent particles. In practice, the degree of anisotropy would be limited by the available value of ϵb (and/or ϵa).

Abstract 3056: Human ovarian cancer stem cells: In vitro cultivation and characterization

Abstract Cancer stem cells (CSC) constitute a miniscule population within the heterogeneous cells of cancer tissues, but they can self-renew, differentiate and recapitulate the tumors. In the absence of serum, CSC from some solid tumors are capable of proliferation in vitro under sphere-forming conditions. We have now established spheroid culture conditions for cultivating ovarian cancer cells derived from surgical specimen. These spheroid cells are tumorigenic when explanted into NOD/Shi-scid, IL-2Rγnull mice, and immuno-histological analysis indicates that the resulting tumors are indistinguishable from the originals. When serum is added to the in vitro culture media, the spheroid cells differentiate, which is associated with the down-regulation of the stem cell-specific regulators Nanog, Sox2, and ALDH1A1 and the up-regulation of cytokeratin. Expression of two of the regulators was essential for the sphere cell maintenance because shRNA-mediated knockdown of either Sox2 or ALDH1A1 inhibited cell proliferation. The differentiated cells, when returned to the sphere-forming serum-free conditions, were capable of reforming spheroids and re-expression of the stem cell markers. Single cell gene expression analysis of spheroid cells and the differentiated cells revealed that these two cell populations were clearly different, and that the reverting spheroid cells were similar to the original spheroid population. These findings indicated that the differentiation of the spheroid stem cells was highly reversible. Unexpectedly, the serum-induced differentiation caused the cell population to become more resistant to paclitaxel, one of the key ovarian cancer chemotherapy drugs, whereas de-differentiation/reversion back to spheroids rendered the cells paclitaxel-sensitive again. The intriguing clinical implications of these findings will be discussed. Citation Format: Tatsuya Ishiguro, Hirokazu Ohata, Hitoshi Nakagama, Koji Okamoto, Kenichi Tanaka, Takayuki Enomoto. Human ovarian cancer stem cells: In vitro cultivation and characterization. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3056. doi:10.1158/1538-7445.AM2014-3056

Galaxy And Mass Assembly (GAMA): stellar mass functions by Hubble type

We present an estimate of the galaxy stellar mass function and its division by morphological type in the local (0.025 < z < 0.06) Universe. Adopting robust morphological classifications as previously presented (Kelvin et al.) for a sample of 3,727 galaxies taken from the Galaxy And Mass Assembly survey, we define a local volume and stellar mass limited sub-sample of 2,711 galaxies to a lower stellar mass limit of M = 10^9.0 M_sun. We confirm that the galaxy stellar mass function is well described by a double Schechter function given by M* = 10^10.64 M_sun, {\alpha}1 = -0.43, {\phi}*1 = 4.18 dex^-1 Mpc^-3, {\alpha}2 = -1.50 and {\phi}*2 = 0.74 dex^-1 Mpc^-3. The constituent morphological-type stellar mass functions are well sampled above our lower stellar mass limit, excepting the faint little blue spheroid population of galaxies. We find approximately 71+3-4% of the stellar mass in the local Universe is found within spheroid dominated galaxies; ellipticals and S0-Sas. The remaining 29+4-3% falls predominantly within late type disk dominated systems, Sab-Scds and Sd-Irrs. Adopting reasonable bulge-to-total ratios implies that approximately half the stellar mass today resides in spheroidal structures, and half in disk structures. Within this local sample, we find approximate stellar mass proportions for E : S0-Sa : Sab-Scd : Sd-Irr of 34 : 37 : 24 : 5.

An inverse approach to constraining strain and vorticity using rigid clast shape preferred orientation data

We describe a three-part approach for modeling shape preferred orientation (SPO) data of spheroidal clasts. The first part consists of criteria to determine whether a given SPO and clast shape are compatible. The second part is an algorithm for randomly generating spheroid populations that match a prescribed SPO and clast shape. In the third part, numerical optimization software is used to infer deformation from spheroid populations, by finding the deformation that returns a set of post-deformation spheroids to a minimally anisotropic initial configuration. Two numerical experiments explore the strengths and weaknesses of this approach, while giving information about the sensitivity of the model to noise in data. In monoclinic transpression of oblate rigid spheroids, the model is found to constrain the shortening component but not the simple shear component. This modeling approach is applied to previously published SPO data from the western Idaho shear zone, a monoclinic transpressional zone that deformed a feldspar megacrystic gneiss. Results suggest at most 5 km of shortening, as well as pre-deformation SPO fabric. The shortening estimate is corroborated by a second model that assumes no pre-deformation fabric.

WHY BARYONS MATTER: THE KINEMATICS OF DWARF SPHEROIDAL SATELLITES

We use high resolution cosmological simulations of Milky Way-mass galaxies that include both baryons and dark matter to show that baryonic physics (energetic feedback from supernovae and subsequent tidal stripping) significantly reduces the dark matter mass in the central regions of luminous satellite galaxies. The reduced central masses of the simulated satellites reproduce the observed internal dynamics of Milky Way and M31 satellites as a function of luminosity. We use these realistic satellites to update predictions for the observed velocity and luminosity functions of satellites around Milky Way-mass galaxies when baryonic effects are accounted for. We also predict that field dwarf galaxies in the same luminosity range as the Milky Way classical satellites should not exhibit velocities as low as the satellites, since the field dwarfs do not experience tidal stripping. Additionally, the early formation times of the satellites compared to field galaxies at the same luminosity may be apparent in the star formation histories of the two populations. Including baryonic physics in Cold Dark Matter models naturally explains the observed low dark matter densities in the Milky Way's dwarf spheroidal population. Our simulations therefore resolve the tension between kinematics predicted in Cold Dark Matter theory and observations of satellites, without invoking alternative forms of dark matter.

The nature of faint fuzzies from the kinematics of NGC 1023

Faint fuzzies are metal-rich apparently-old star clusters with unusually large radii (7-15 pc), found mostly in S0 galaxies, whose source remain obscure. To identify their origins, we compare planetary nebulae and neutral hydrogen with faint fuzzy positions and line-of-sight velocities in NGC1023. In this way, we rule out scenarios in which these objects are associated with an on-going merger or with a spheroid population in NGC1023. Their kinematics are indistinguishable from the stellar disk population in this galaxy, and we conclude that faint fuzzies are most likely just remnant open clusters. Their observed association with S0s then simply reflects the difficulty of identifying such objects in later-type disk galaxies.

Abstract B65: The mitochondrial antioxidant Superoxide Dismutase 2 is necessary for ovarian cancer spheroid formation

Abstract The formation of cellular spheroid aggregates in the Intraperitoneal Cavity (IP) is considered to be an important step in the metastatic progression of ovarian cancer. Spheroids may represent a unique morphological adaptation that enhances long-term survival of tumor cells in the IP cavity, reminiscent of dormant cell populations. Like other dormant tumor cells, in vivo-isolated and in vitro-cultured spheroids exhibit enhanced chemoresistance and display markers of quiescence. We show that expression of mitochondrial superoxide dismutase (Sod2), which regulates mitochondrial redox balance, is significantly increased during formation of dense spheroids from a number of ovarian cancer cell lines. This is accompanied by increases in the quiescence marker p27(kip1). Importantly, siRNA and shRNA knock-down of Sod2 compromise spheroid formation and integrity, and abrogate increases in p27(kip1) expression in anchorage-independent 3D cultures. Mechanistically, it is likely that increases in Sod2 expression protect cells from build-up of mitochondrial and IP cavity-derived ROS, enhancing their survival as dormant spheroid populations. In addition, bioenergetic data suggest that Sod2 is directly involved in enhancing the mitochondrial integrity of tumor cells within spheroid aggregates. This leads to a metabolic profile that is associated with a slowing in ATP demand and an enhanced respiratory reserve capacity, with Sod2 being intricately involved in manipulating these changes. Enhanced Sod2 expression, a concomitant decrease in mitochondrial ROS and changes in mitochondrial function are likely indicators of a quiescence adaptation of tumor spheroids, necessary for survival in the IP cavity. Manipulating mitochondrial function and redox balance by effectively targeting mitochondrial antioxidant enzymes may provide novel therapeutic strategies to combat recurrence and metastatic spread of ovarian cancer. Citation Format: LP Madhubhani Hemachandra, Usawadee Dier, Larissa M. Uusitalo, Nadine Hempel. The mitochondrial antioxidant Superoxide Dismutase 2 is necessary for ovarian cancer spheroid formation. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B65.

β1-integrin via NF-κB signaling is essential for acquisition of invasiveness in a model of radiation treated in situ breast cancer

IntroductionDuctal carcinoma in situ (DCIS) is characterized by non-invasive cancerous cell growth within the breast ducts. Although radiotherapy is commonly used in the treatment of DCIS, the effect and molecular mechanism of ionizing radiation (IR) on DCIS are not well understood, and invasive recurrence following radiotherapy remains a significant clinical problem. This study investigated the effects of IR on a clinically relevant model of Akt-driven DCIS and identified possible molecular mechanisms underlying invasive progression in surviving cells.MethodsWe measured the level of phosphorylated-Akt (p-Akt) in a cohort of human DCIS specimens by immunohistochemistry (IHC) and correlated it with recurrence risk. To model human DCIS, we used Akt overexpressing human mammary epithelial cells (MCF10A-Akt) which, in three-dimensional laminin-rich extracellular matrix (lrECM) and in vivo, form organotypic DCIS-like lesions with lumina expanded by pleiomorphic cells contained within an intact basement membrane. In a population of cells that survived significant IR doses in three-dimensional lrECM, a malignant phenotype emerged creating a model for invasive recurrence.ResultsP-Akt was up-regulated in clinical DCIS specimens and was associated with recurrent disease. MCF10A-Akt cells that formed DCIS-like structures in three-dimensional lrECM showed significant apoptosis after IR, preferentially in the luminal compartment. Strikingly, when cells that survived IR were repropagated in three-dimensional lrECM, a malignant phenotype emerged, characterized by invasive activity, up-regulation of fibronectin, α5β1-integrin, matrix metalloproteinase-9 (MMP-9) and loss of E-cadherin. In addition, IR induced nuclear translocation and binding of nuclear factor-kappa B (NF-κB) to the β1-integrin promoter region, associated with up-regulation of α5β1-integrins. Inhibition of NF-κB or β1-integrin signaling abrogated emergence of the invasive activity.ConclusionsP-Akt is up-regulated in some human DCIS lesions and is possibly associated with recurrence. MCF10A-Akt cells form organotypic DCIS-like lesions in three-dimensional lrECM and in vivo, and are a plausible model for some forms of human DCIS. A population of Akt-driven DCIS-like spheroids that survive IR progresses to an invasive phenotype in three-dimensional lrECM mediated by β1-integrin and NF-κB signaling.

The redshift and mass dependence on the formation of the Hubble sequence at z &gt; 1 from CANDELS/UDS

In this paper we present a detailed study of the structures and morphologies of a sample of 1188 massive galaxies with M* ≥ 1010 M⊙ between redshifts z = 1 and 3 within the Ultra Deep Survey (UDS) region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) field. Using this sample we determine how galaxy structure and morphology evolve with time, and investigate the nature of galaxy structure at high redshift. We visually classify our sample into discs, ellipticals and peculiar systems and correct for redshift effects on these classifications through simulations. We find significant evolution in the fractions of galaxies at a given visual classification as a function of redshift. The peculiar population is dominant at z > 2 with a substantial spheroid population, and a negligible disc population. We compute the transition redshift, ztrans, where the combined fraction of spheroidal and disc galaxies is equal to that of the peculiar population, as ztrans = 1.86 ± 0.62 for galaxies in our stellar mass range. We find that this transition changes as a function of stellar mass, with Hubble-type galaxies becoming dominant at higher redshifts for higher mass galaxies (ztrans = 2.22 ± 0.82), than for the lower mass galaxies (ztrans = 1.73 ± 0.57). Higher mass galaxies become morphologically settled before their lower mass counterparts, a form of morphological downsizing. We furthermore compare our visual classifications with the Sérsic index, the concentration, asymmetry and clumpiness (CAS) parameters, star formation rate and rest-frame U − B colour. We find links between the colour of a galaxy, its star formation rate and how extended or peculiar it appears. Finally, we discuss the negligible z > 2 disc fraction based on visual morphologies and speculate that this is an effect of forming disc appearing peculiar through processes such as violent disc instabilities or mergers. We conclude that to properly define and measure high-redshift morphology and structure a new and more exact classification scheme is needed.