Effects of ezrin silencing on pancreatic cancer cell line Panc-1 / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore the effects of ezrin silencing on pancreatic cancer cell line Panc-1.</p><p><b>METHODS</b>Pancreatic cancer cell line Panc-1 was transfected with ezrin silencing plasmid. The proliferation and the cell cycle status were determined by CCK-8 assay and flow cytometry analysis, respectively. Cellular membrane protrusions/microvilli formation were visualized by scanning election microscopy. Colony formation assay was used to determine the cell anchor-independent growth ability in vitro. Trans-filter migration and invasion assays were performed with 8 µm pore inserts in a 24-well BioCoat chamber with/without Matrigel.</p><p><b>RESULTS</b>Ezrin silencing decreased cellular protrusions/microvilli formation, anchorage-independent growth, cell migration and invasion, but had no effects on cell proliferation in vitro and cell cycle, in pancreatic cancer cell line Panc-1.</p><p><b>CONCLUSION</b>Ezrin expression affects the cellular protrusions/microvilli formation, anchorage-independent growth, cell migration and invasion in pancreatic cancer cell line Panc-1.</p>

A single E726Q mutation in the membrane proximal α-helix of integrin β3 subunit induces membrane blebbing by disrupting the membrane-actin cortex interaction / 中国实验血液学杂志

The membrane proximal α helix of integrin β subunit cytoplasmic tails plays an important functional role by interacting with various intracellular proteins, namely talin, α-actinin or skelemin. This study was designed to investigate the functional role of 5 highly conserved charged amino acids (R(724), K(725), E(726), E(731), E(733)) within this α helix by site-directed mutagenesis. The result showed that CHO cells expressing the αIIbβ3E726Q mutant had the most prominent phenotype and characterized by defective cell spreading on immobilized fibrinogen. In addition, this E726Q mutation induced membrane blebbing in cells adherent on fibrinogen, and this blebbing could be inhibited by the myosin light chain ATPase inhibitor blebbistatin. It is concluded that the membrane proximal α-helix of integrin β3 subunit is important in linking the phospholipid membrane to the submembraneous actin cortex.

Morphological signs of survival cultured adult rat cardiomyocytes / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To clarify the key morphological signs for the survival of adult rat cardiomyocytes in primary culture.</p><p><b>METHODS</b>The adult rat hearts were retrogradely superfused by Langendorff apparatus. Cardiomyocytes were digested by collagenase I and cultured in three groups: (1) Serum free medium + BA (Bongkrekic acid, apoptotic inhibitor), (2) 5% serum medium, and (3) 5% serum medium + BA. The morphological alterations were observed and the percentage of rod-shaped cardiomyocytes, the apoptotic rate of cells, the rate of pseudopodium formation and the nuclear distances of cardiomyocytes were detected during culture.</p><p><b>RESULTS</b>(1) The percentage of rod-shaped cardiomyocytes decreased gradually in the first 3 days of cell culture. The percentage of rod-shaped cardiomyocytes cultured without fetal bovine serum (FBS) decreased more rapidly than those cultured with FBS. No differences were noticed between with and without the addition of apoptotic inhibitor BA. The apoptotic rate of cardiomyocytes increased in the first 3 days of cell culture, and the apoptotic rate of cells cultured without FBS increased more than that cultured with FBS. Also BA had no effect on apoptotic rate. (2) Cardiomyocytes cultured with FBS spread from the intercalated disk and extended pseudopodium on the second or third day of cell culture. Cardiomyocytes with thin membranous pseudopodium developed would survive and spread laterally at the 6th day of culture. Cells with the elongated morphology gradually spread extensively and took on a spheroidal shape. Myofibrils gradually lost their parallel. Cells cultured without FBS had no pseudopodium formation. The intercalated disk of cells gradually changed blunt. There was no effect on the rate of pseudopodium formation when added with apoptotic inhibitor BA. (3) Cytoskeletal remodeling occurred in survived cardiomyocytes. After 6 days of culture, cardiomyocytes exhibited characteristic of redifferentiation. (4) The distance between nuclei decreased in a single cardiomyocyte cultured with FBS for the cytoskeletal reconstruction, whereas it remained unchanged in cardiomyocytes cultured without FBS.</p><p><b>CONCLUSION</b>We clarify the pseudopodium developed on the second or third day of cell culture will be the critical morphological signs of survival cultured adult rat cardiomyocytes. It is necessary to add FBS for the formation of pseudopodium.</p>

CD44 is involved in CXCL-12 induced acute myeloid leukemia HL-60 cell polarity

CXCL-12 and its receptor CXCR4 participate in breast cancer and melanoma cell metastasis to bone and lymphoid nodes. CD44, as a receptor for hyaluronic acid, is involved in lymphocyte recirculation, homing, adhesion and migration. But the role of CD44 in CXCL-12 induced leukemia cell migration still remains unclear. The present study showed that CXCL-12 stimulation induced the rapid internalization of CXCR4 and facilitated the formation of lamellipodia and uropod in acute leukemia cell line HL-60. CXCL-12 also induced CD44 translocation into the uropod, while CD44 remained evenly distributed on the untreated cell membranes. Results suggest that CD44 participates in CXCL-12 induced cell polarization and subsequent cell migration.

Apoptogenic effect of the lipophilic o-naphthoquinone CG 10-248 on rat hepatocytes: light and electron microscopy studies

CG 10-248 (3,4-dihydro-2,2-dimethyl-9-chloro-2H-naphtho[1,2b]pyran-5,6-dione; CG-NQ), a beta-lapachone analogue, modified the ultrastructure of rat hepatocytes, as demonstrated by light and electron microscopy. After 4 h incubation with 100 microM CG-NQ, the following effects were observed: (a) nuclear chromatin condensation; (b) chromatin fragmentation; (c) displacement of mitochondria, concentrated around the nucleus; (d) disruption or expansion of mitochondrial outer or inner membranes, respectively; (e) displacement and alteration of endoplasmic reticulum (rough and smooth); (f) decrease of microvilli; (g) blebbing of plasma membrane and production of apoptotic bodies formed by folding of plasma membrane fragments around mitochondria or peroxysomes; and (h) production of hydrogen peroxide. Expression of such effects varied according to hepatocyte samples and taken together strongly support an apoptotic action of CG-NQ dependent on reactive oxygen species.

Theiler virus-GDVII strain (TMEV-GDVII) infection of cultured astrocytes. An image analysis of its effects on cell activation

Our original aim was to determine whether dBcAMP-induced activation of cultured astrocytes affected the course of subsequent viral infection. After 2 h exposure of 2-day-old first subculture of mouse astrocytes to dBcAMP 1 mM, cell monolayers grown in glass coverslips of Leighton tubes were inoculated with 10(3) PFU of Theiler virus-GDVII strain (TMEV-GDVII). At 9 days post-infection (pi), viral infectivity persisted in supernatants from dBcAMP-treated cultures, but was no longer detectable in non-stimulated controls. The relatively spared astroglial monolayer at day 1 pi, hardly affected by progressive viral cytolytic effect, was chosen for immunolabeled cell count, whether by viral antigen or GFAP. To this end, 20 fields for each coverslip were digitalized at 250x final magnification. In dBcAMP treated cultures, viral antigen(+) cells were fewer and lower in percentage versus infected cultures lacking stimulation. As regards GFAP staining, stimulation or infection per se induced a greater number and percentage of labeled astrocytes. According to morphometric characterization, such increase was due to a greater number of process-bearing astrocytes. It may be concluded that, regardless of previous dBcAMP treatment, early TMEV-GDVII infection enhanced immunocytochemical and morphological differentiation in cultured astrocytes.