scholarly journals Integrin Beta-3

2020 ◽  
Author(s):  
Keyword(s):  
Integrin Beta 3

scholarly journals In Vivo RNA Interference Screening Identifies a Leukemia-Specific Dependence on Integrin Beta 3 Signaling

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 758-758
Author(s):  
◽  
Fatima Al-Shahrour ◽  
Kimberly A. Hartwell ◽  
Lisa P Chu ◽  
Jaras Marcus ◽  
...  
Keyword(s):  
Rna Interference ◽  
Cell Growth ◽  
Leukemia Cell ◽  
Leukemia Cells ◽  
Growth And Survival ◽  
Integrin Beta 3 ◽  
Shrna Screen ◽  
Primary Leukemia

Abstract Abstract 758 Primary leukemia stem cells (LSCs) reside in an in vivo microenvironment that supports the growth and survival of malignant cells. Despite the increasing understanding of the importance of niche interactions and primary cell biology in leukemia, many studies continue to focus on cell autonomous processes in artificial model systems. The majority of strategies to-date that attempt to define therapeutic targets in leukemia have relied on screening cell lines in culture; new strategies should incorporate the use of primary disease within a physiologic niche. Using a primary murine MLL-AF9 acute myeloid leukemia (AML) model highly enriched for LSCs, we performed an in vivo short hairpin RNA (shRNA) screen to identify novel genes that are essential for leukemia growth and survival. LSCs infected with pools of shRNA lentivirus were transplanted and grown in recipient mice for 2 weeks, after which bone marrow and spleen cells were isolated. Massively parallel sequencing of infected LSCs isolated before and after transplant was used to quantify the changes in shRNA representation over time. Our in vivo screens were highly sensitive, robust, and reproducible and identified a number of positive controls including genes required for MLL-AF9 transformation (Ctnnb1, Mef2c, Ccna1), genes universally required for cell survival (Ube2j2, Utp18), and genes required in other AML models (Myb, Pbx1, Hmgb3). In our primary and validation screens, multiple shRNAs targeting Integrin Beta 3 (Itgb3) were consistently depleted by more than 20-fold over two weeks in vivo. Follow up studies using RNA interference (RNAi) and Itgb3−/− mice identified Itgb3 as essential for murine leukemia cells growth and transformation in vivo, and loss of Itgb3 conferred a statistically significant survival advantage to recipient mice. Importantly, neither Itgb3 knockdown or genetic loss impaired normal hematopoietic stem and progenitor cell (HSPC) function in 16 week multilineage reconstitution assays. We further identified Itgav as the heterodimeric partner of Itgb3 in our model, and found that knockdown of Itgav inhibited leukemia cell growth in vivo. Consistent the therapeutic aims or our study, flow cytometry on primary human AML samples revealed ITGAV/ITGB3 heterodimer expression. To functionally assess the importance of gene expression in a human system, we performed another RNAi screen on M9 leukemia cells, primary human cord blood CD34+ cells transduced with MLL-ENL that are capable of growing in vitro or in a xenotransplant model in vivo. We found that ITGB3 loss inhibited M9 cell growth in vivo, but not in vitro, consistent with the importance of ITGB3 in a physiologic microenvironment. We explored the signaling pathways downstream of Itgb3 using an additional in vivo, unbiased shRNA screen and identified Syk as a critical mediator of Itgb3 activity in leukemia. Syk knockdown by RNAi inhibited leukemia cell growth in vivo; downregulation of Itgb3 expression resulted in decreased levels of Syk phosphorylation; and expression of an activated form of Syk, TEL-SYK, rescued the effects of Itgb3 knockdown on leukemia cell growth in vivo. To understand cellular processes controlled by Itgb3, we performed gene expression studies and found that, in leukemia cells, Itgb3 knockdown induced differentiation and inhibited multiple previously published LSC transcriptional programs. We confirmed these results using primary leukemia cell histology and a model system of leukemia differentiation. Finally, addition of a small molecule Syk inhibitor, R406, to primary cells co-cultured with bone marrow stroma caused a dose-dependent decrease in leukemia cell growth. Our results establish the significance of the Itgb3 signaling pathway, including Syk, as a potential therapeutic target in AML, and demonstrate the utility of in vivo RNA interference screens. Disclosures: Armstrong: Epizyme: Consultancy.

scholarly journals Integrin Beta-3 Genetic Variants Predict the Risk of Thrombo-Embolic Events in Patients with Colorectal Cancer

2014 ◽  
Vol 25 ◽  
pp. iv191
Author(s):  
G. Prager ◽  
A. Schuler ◽  
C. Pausz ◽  
D. Bianconi ◽  
H. Lenz ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Genetic Variants ◽  
Integrin Beta 3

scholarly journals Osteopontin Promotes Trophoblast Invasion in the Smooth Muscle Cell-Endothelial Co-Culture At Least Via Targeting Integrin αvβ3

2020 ◽  
Vol 29 ◽  
pp. 096368972096597
Author(s):  
Ru Ke ◽  
Liting Zheng ◽  
Falan Zhao ◽  
Junxia Xia
Keyword(s):  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Culture Media ◽  
Integrin Αvβ3 ◽  
Trophoblast Invasion ◽  
Invasive Potential ◽  
Transwell Invasion Assay ◽  
Invasive Capacity ◽  
Underlying Mechanisms ◽  
Integrin Beta 3

Preeclampsia is a pregnancy disorder, whereas the underlying mechanisms and etiological factors of this complication remain elusive. Studies have reported that decreased invasiveness of trophoblast cells, immunity disorder in the maternal–fetal interface, and oxidative stress may contribute to the development of preeclampsia. In the present study, we firstly co-cultured the smooth muscle cells (SMCs) and endothelial cells (ECs) to mimic the decidua and myometrium interface and examined the effects of osteopontin (OPN) on the invasive potential of trophoblasts in the SMC-EC co-culturing system. Our results showed that HTR-8/SVneo cells after hypoxia treatment showed enhanced invasive potential in the SMC-EC co-culturing system. OPN levels in the culture media from hypoxia-treated HTR-8/SVneo cells were significantly increased. More importantly, OPN treatment upregulated integrin, beta 3 and integrin, beta 5 expression in HTR-8/SVneo cells, and promoted HTR-8/SVneo cell invasion in the transwell invasion assay and SMC-EC co-culturing system. Mechanistically, treatment with integrin αvβ3 inhibitor significantly attenuated the enhanced invasive potential of HTR-8/SVneo cells treated with OPN in the SMC-EC co-culturing system. In conclusion, our study for the first time established the SMC-EC co-culturing system to examine the invasive potential of trophoblasts. Our results indicated that OPN promoted the invasive capacity of trophoblasts via at least targeting αvβ3 in the EC-SMC co-culturing system. Future studies were required to further validate the EC-SMC co-culturing system and to determine the molecular mechanisms of OPN-mediated trophoblast invasion.

The effects of estrogen and progesterone on prostaglandins and integrin beta 3 (β3) subunit expression in primary cultures of bovine endometrial cells

2003 ◽  
Vol 25 (2) ◽  
pp. 141-154 ◽  
Author(s):  
Sarah Kimmins ◽  
Hai Choo Lim ◽  
Julie Parent ◽  
Michel A. Fortier ◽  
Leslie A. MacLaren
Keyword(s):  
Primary Cultures ◽  
Endometrial Cells ◽  
Subunit Expression ◽  
Integrin Beta 3

scholarly journals A new alternative transcript encodes a 60 kDa truncated form of integrin β3

1994 ◽  
Vol 300 (1) ◽  
pp. 69-74 ◽  
Author(s):  
I Djaffar ◽  
Y P Chen ◽  
C Creminon ◽  
J Maclouf ◽  
A M Cieutat ◽  
...  
Keyword(s):  
Stop Codon ◽  
Human Platelets ◽  
Alternative Transcript ◽  
Truncated Form ◽  
Reading Frame ◽  
Cell Library ◽  
Beta Integrin ◽  
Hel Cells ◽  
Integrin Beta 3 ◽  
Alternative Beta

A cDNA for integrin beta 3 isolated from a human erythroleukaemia (HEL) cell library contained a 340 bp insert at position 1281. This mRNA, termed beta 3c, results from the use of a cryptic AG donor splice site in intron 8 of the beta 3 gene, and is different from a previously described alternative beta 3 mRNA. The predicted open reading frame of beta 3C stops at a TAG stop codon 69 bp downstream from position 1281. It starts with the signal peptide and the 404 N-terminal extracellular residues of beta 3, encompassing the ligand binding sites, followed by 23 C-terminal intron-derived residues, corresponding to a truncated form of beta 3 lacking the cysteine-rich, transmembrane and cytoplasmic domains. Expression of beta 3C mRNA was demonstrated in human platelets, megakaryocytes, endothelial cells and HEL cells by reverse transcriptase/PCR. The beta 3C transcript was also demonstrated in the mouse, suggesting its conservation through evolution. Finally, a 60 kDa polypeptide corresponding to the beta 3C alternative transcript was demonstrated in platelets by Western blotting using a polyclonal antibody raised against a synthetic peptide designed from the beta 3C intronic sequence. Taken together, these results suggest a biological role for beta 3C, the first alternative transcript showing an altered extracellular domain of a beta integrin.

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