Human colonic organoids for understanding early events of familial adenomatous polyposis pathogenesis.

Patients with familial adenomatous polyposis (FAP) harbor mutations in the APC gene and will develop adenoma and early colorectal cancer. There is no validated treatment, and animal models are not sufficient to study FAP. Our aim was to investigate the early events associated with FAP using the intestinal organoid model in a single-center study using biopsies from nonadenomatous and adenomatous colonic mucosa of FAP patients and from healthy controls (HCs).

Intestinal organoids to model Salmonella infection and its impact on progenitors.

In order to survive and replicate, Salmonella has evolved mechanisms to gain access to intestinal epithelial cells of the crypt. However, the impact of Salmonella Typhimurium on stem cells and progenitors, which are responsible for the ability of the intestinal epithelium to renew and protect itself, remains unclear. Given that intestinal organoids growth is sustained by stem cells and progenitors activity, we have used this model to document the effects of Salmonella Typhimurium infection on epithelial proliferation and differentiation, and compared it to an in vivo model of Salmonella infection in mice.

Daphnanes diterpenes from the latex of Hura crepitans L. and their PKCζ-dependent anti-proliferative activity on colorectal cancer cells.

Hura crepitans L. (Euphorbiaceae) is a thorn-covered tree widespread in South America, Africa and Asia which produces an irritating milky latex containing numerous secondary metabolites, notably daphnane-type diterpenes known as Protein Kinase C activators. Fractionation of a dichloromethane extract of the latex led to the isolation of five new daphnane diterpenes (1-5), along with two known analogs (6-7) including huratoxin.

Prenatal stress induces changes in PAR2- and M3-dependent regulation of colon primitive cells.

Prenatal stress is associated with a high risk of developing adult intestinal pathologies, such as irritable bowel syndrome, chronic inflammation, and cancer. Although epithelial stem cells and progenitors have been implicated in intestinal pathophysiology, how prenatal stress could impact their functions is still unknown. We have investigated the proliferative and differentiation capacities of primitive cells using epithelial crypts isolated from colons of adult male and female mice whose mothers have been stressed during late gestation.

GSK3β, a Master Kinase in the Regulation of Adult Stem Cell Behavior.

In adult stem cells, Glycogen Synthase Kinase 3β (GSK3β) is at the crossroad of signaling pathways controlling survival, proliferation, adhesion and differentiation. The microenvironment plays a key role in the regulation of these cell functions and we have demonstrated that the GSK3β activity is strongly dependent on the engagement of integrins and protease-activated receptors (PARs). Downstream of the integrin αβ or PAR activation, a molecular complex is organized around the scaffolding proteins RACK1 and β-arrestin-2 respectively, containing the phosphatase PP2A responsible for GSK3β activation.

Daphnanes diterpenes from the latex of Hura crepitans L. And activity against human colorectal cancer cells Caco-2.

Hura crepitans (Euphorbiaceae) is a tree from South America that produces an irritant latex used as a fish poison. A bio-guided fractionation of an ethanolic extract of the latex led to the isolation and structural identification of three known daphnane-type diterpenes (1-3) including huratoxin (1), together with two new analogs (4, 5). Compound 1 was found to exhibit significant and selective cell growth inhibition against the colorectal cancer cell line Caco-2, with morphological modifications suggesting formations mimicking the intestinal crypt architecture.

Characterization of Human Colon Organoids From Inflammatory Bowel Disease Patients.

Inflammatory Bowel Diseases (IBD) are chronic inflammatory disorders, where epithelial defects drive, at least in part, some of the pathology. We reconstituted human intestinal epithelial organ, by using three-dimension culture of human colon organoids. Our aim was to characterize morphological and functional phenotypes of control (non-IBD) organoids, compared to inflamed organoids from IBD patients.

Sexual dimorphism in PAR-dependent regulation of primitive colonic cells.

Background: Sexual dimorphism in biological responses is a critical knowledge for therapeutic proposals. However, gender differences in intestinal stem cell physiology have been poorly studied. Given the important role of the protease-activated receptor PAR in the control of colon epithelial primitive cells and cell cycle genes, we have performed a sex-based comparison of its expression and of the effects of PAR activation or knockout on cell proliferation and survival functions.

FAK alternative splice mRNA variants expression pattern in colorectal cancer.

The Focal adhesion kinase (FAK) is a ubiquitous cytoplasmic tyrosine-kinase promoting tumor progression and metastasis processes by acting in cancer cells and their tumor microenvironment partners. FAK overexpression in primary colon tumors and their metastasis is associated to poor colorectal cancer (CRC) patients' outcome. Eight FAK mRNA alternative splice variants have been described and contribute to additional level of FAK activity regulation, some of them corresponding to overactivated FAK isoforms.

Thrombin modifies growth, proliferation and apoptosis of human colon organoids: a protease-activated receptor 1- and protease-activated receptor 4-dependent mechanism.

Background And Purpose: Thrombin is massively released upon tissue damage associated with bleeding or chronic inflammation. The effects of this thrombin on tissue regrowth and repair has been scarcely addressed and only in cancer cell lines. Hence, the purpose of the present study was to determine thrombin's pharmacological effects on human intestinal epithelium growth, proliferation and apoptosis, using three-dimensional cultures of human colon organoids.

[Progress in prostate cancer study: 3D cell culture enables the ex vivo reproduction of tumor characteristics].

Despite new therapeutics options, Prostate Cancer (PCa) remains a public health challenge because of its high incidence and mortality. Limits in PCa research come from the lack of in vitro and in vivo models that mimic the human disease. Currently, 2D in vitro tissue culture models of PCa are widely used but they present numerous limits.

Anti-inflammatory and anticancer effects of flavonol glycosides from Diplotaxis harra through GSK3β regulation in intestinal cells.

Context And Objective: Diplotaxis harra (Forssk.) Boiss. (Brassicaceae) is traditionally used as an antidiabetic, anti-inflammatory or anticancer agent.

PAR2-dependent activation of GSK3β regulates the survival of colon stem/progenitor cells.

Protease-activated receptors PAR1 and PAR2 play an important role in the control of epithelial cell proliferation and migration. However, the survival of normal and tumor intestinal stem/progenitor cells promoted by proinflammatory mediators may be critical in oncogenesis. The glycogen synthase kinase-3β (GSK3β) pathway is overactivated in colon cancer cells and promotes their survival and drug resistance.

Cucurbitacins from the Leaves of Citrullus colocynthis (L.) Schrad.

Two new tetracyclic cucurbitane-type triterpene glycosides were isolated from an ethyl acetate extract of Citrullus colocynthis leaves together with four known cucurbitacins. Their structures were established on the basis of their spectroscopic data (mainly NMR and mass spectrometry). Evaluation of the in vitro cytotoxic activity of the isolated compounds against two human colon cancer cell lines (HT29 and Caco-2) and one normal rat intestine epithelial cell line (IEC6), revealed that one of the isolated compounds presented interesting specific cytotoxic activity towards colorectal cell lines.

Antioxidant activity and hepatoprotective potential of Hammada scoparia against ethanol-induced liver injury in rats.

The present work was aimed at studying the antioxidative activity and hepatoprotective effects of methanolic extract (ME) of Hammada scoparia leaves against ethanol-induced liver injury in male rats. The animals were treated daily with 35 % ethanol solution (4 g kg(-1) day(-1)) during 4 weeks. This treatment led to an increase in the lipid peroxidation, a decrease in antioxidative enzymes (catalase, superoxide dismutase, and glutathione peroxidase) in liver, and a considerable increase in the serum levels of aspartate and alanine aminotransferase and alkaline phospahatase.

Focal adhesion kinase splice variants maintain primitive acute myeloid leukemia cells through altered Wnt signaling.

Focal adhesion kinase (FAK) activity contributes to many advanced cancer phenotypes, but little is known about its role in human acute myeloid leukemia (AML). Here, we show that FAK splice variants are abnormally expressed in the primitive leukemic cells of poor prognosis AML patients. In the CD34(+) 38(-) 123(+) long-term culture-initiating cell-enriched leukemic cells of these patients, FAK upregulates expression of Frizzled-4 and phosphorylates Pyk2 to enable the required association of Pyk2 with the Wnt5a/Frizzled-4/LRP5 endocytosis complex and downstream activation of β-catenin, thereby replacing the Wnt3a-controlled canonical pathway used by normal hematopoietic stem cells.

Hammada scoparia flavonoids and rutin kill adherent and chemoresistant leukemic cells.

In search for compounds able to reduce cell adhesion-mediated drug resistance (CAM-DR), we studied effects of Hammada scoparia extracts on leukemic cells adherent or in suspension. We show that H. scoparia flavonoidic fraction and its compound rutin induce apoptosis specifically in adherent leukemic cells and abolish CAM-DR.

A New alpha5beta1 integrin-dependent survival pathway through GSK3beta activation in leukemic cells.

Background: Cell survival mediated by integrin engagement has been implicated in cell adhesion-mediated drug resistance. We have recently demonstrated that the activation of glycogen synthase kinase 3 beta (GSK3beta) is a new pathway supporting the chemoresistance of leukemic cells adhered to fibronectin.

Methodology And Principal Findings: We show here that in conditions of serum starvation, the fibronectin receptor alpha(5)beta(1) integrin, but not alpha(4)beta(1), induced activation of GSK3beta through Ser-9 dephosphorylation in adherent U937 cells.

Anaplastic lymphoma kinase is a dependence receptor whose proapoptotic functions are activated by caspase cleavage.

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase, initially discovered as part of the NPM-ALK fusion protein, resulting from the t(2;5) translocation that is frequently associated with anaplastic large-cell lymphomas. The native ALK protein is normally expressed in the developing and, at a weaker level, adult nervous system. We recently demonstrated that the oncogenic, constitutively kinase-activated NPM-ALK protein was antiapoptotic when expressed in Jurkat lymphoblastic cells treated with cytotoxic drugs.

Cell adhesion regulates CDC25A expression and proliferation in acute myeloid leukemia.

The effects of cell adhesion on leukemia cell proliferation remain poorly documented and somehow controversial. In this work, we investigated the effect of adhesion to fibronectin on the proliferation of acute myeloid leukemia (AML) cell lines (U937 and KG1a) and CD34+ normal or leukemic primary cells. We observed an increased rate of proliferation of AML cells when adhered to fibronectin, concomitant with accelerated S-phase entry and accumulation of CDC25A.

Emerging roles of phosphatidylinositol monophosphates in cellular signaling and trafficking.

The phosphoinositide metabolism that is highly controlled by a set of kinases, phosphatases and phospholipases leads to the production of several second messengers playing critical roles in intracellular signal transduction mechanisms. Recent discoveries have unraveled unexpected roles for the three phosphatidylinositol monophosphates, PtdIns(3)P, PtdIns(4)P and PtdIns(5)P, that appear now as important lipid messengers able to specifically interact with proteins. The formation of functionally distinct and independently regulated pools of phosphatidylinositol monophosphates probably contributes to the specificity of the interactions with their targets.

Differential effects of X-ALK fusion proteins on proliferation, transformation, and invasion properties of NIH3T3 cells.

Majority of anaplastic large-cell lymphomas (ALCLs) are associated with the t(2;5)(p23;q35) translocation, fusing the NPM (nucleophosmin) and ALK (anaplastic lymphoma kinase) genes (NPM-ALK). Recent studies demonstrated that ALK may also be involved in variant translocations, namely, t(1;2)(q25;p23), t(2;3)(p23;q21), t(2;17)(p23;q23) and inv(2)(p23q35), which create the TPM3-ALK, TFG-ALK5, CLTC-ALK, and ATIC-ALK fusion genes, respectively. Although overexpression of NPM-ALK has previously been shown to transform fibroblasts, the transforming potential of variant X-ALK proteins has not been precisely investigated.

Expression of focal adhesion kinase in acute myeloid leukemia is associated with enhanced blast migration, increased cellularity, and poor prognosis.

Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase playing an important role in cell motility and survival. However, very little is known about FAK in normal and leukemic myeloid cells. In this study, FAK protein expression and mRNA were detected in 25 of 60 cases (42%) of acute myeloid leukemia (AML).

Phosphoinositide 3-kinase C2alpha is activated upon smooth muscle cell migration and regulated by alpha(v)beta(3) integrin engagement.

The involvement of phosphoinositide 3-kinase C2alpha in vascular smooth muscle cell migration was investigated. Products of phosphoinositide 3-kinase, phosphatidylinositol-3-phosphate, and phosphatidylinositol-3,4-bis-phosphate were increased upon smooth muscle cell migration but their synthesis was affected only partially by phosphoinositide 3-kinase inhibitors, wortmannin and LY-294002. Using specific antibody, we showed that the wortmannin/LY-294002 poorly sensitive phosphoinositide 3-kinase C2alpha is expressed in smooth muscle cells.