scholarly journals Functional Characteristics and Regulated Expression of Alternatively Spliced Tissue Factor: An Update

Cancers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 4652
Author(s):  
Kateryna Matiash ◽  
Clayton S. Lewis ◽  
Vladimir Y. Bogdanov

In human and mouse, alternative splicing of tissue factor’s primary transcript yields two mRNA species: one features all six TF exons and encodes full-length tissue factor (flTF), and the other lacks exon 5 and encodes alternatively spliced tissue factor (asTF). flTF, which is oftentimes referred to as “TF”, is an integral membrane glycoprotein due to the presence of an alpha-helical domain in its C-terminus, while asTF is soluble due to the frameshift resulting from the joining of exon 4 directly to exon 6. In this review, we focus on asTF—the more recently discovered isoform of TF that appears to significantly contribute to the pathobiology of several solid malignancies. There is currently a consensus in the field that asTF, while dispensable to normal hemostasis, can activate a subset of integrins on benign and malignant cells and promote outside-in signaling eliciting angiogenesis; cancer cell proliferation, migration, and invasion; and monocyte recruitment. We provide a general overview of the pioneering, as well as more recent, asTF research; discuss the current concepts of how asTF contributes to cancer progression; and open a conversation about the emerging utility of asTF as a biomarker and a therapeutic target.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1135-1135
Author(s):  
Richard Godby ◽  
Yascha van den Berg ◽  
Ramprasad Srinivasan ◽  
Evgeny Ozhegov ◽  
Henri H Versteeg ◽  
...  

Abstract Abstract 1135 Background. Aside from hemostatic maintenance, Tissue Factor (TF) also plays a major role in such pathophysiological processes as thrombogenesis and cancer progression. TF protein occurs naturally in two forms: full length TF (flTF), a well–studied integral membrane glycoprotein that serves as an obligatory enzymatic co-factor of the serine protease FVIIa, and alternatively spliced TF (asTF), which lacks a transmembrane domain and can be secreted. asTF has a unique 40 amino acid C-terminus and can be detected, alongside flTF, in organized arterial thrombi (Bogdanov et al, Nat Med 2003 Apr; 9(4):458-62). Following the discovery of human asTF, the murine form of asTF (masTF) was identified and characterized (Bogdanov et al, J Thromb Haemost. 2006 Jan;4(1):158-67). Like human asTF, masTF lacks a transmembrane domain due to the exclusion of exon 5 from the primary transcript during its splicing, possesses a unique 93 amino acid C-terminus, and exhibits minimal coagulant potential. Most recently, hasTF was discovered to induce cell adhesion and angiogenesis via integrin ligation, independent of FVIIa, PAR-2 cleavage and/or any other proteolytic events (van den Berg et al, Proc Natl Acad Sci U.S.A. 2009 Nov 17;106(46):19497-502). It has yet to be investigated whether masTF exhibits non-proteolytic biologic activity analogous to that of hasTF. As murine models comprise the preferred in vivo platform in preclinical cardiovascular and cancer research, it is highly warranted to ascertain these possible functional properties of masTF. In this study, we performed an initial set of experiments to address this issue. Results. N-terminally His-tagged recombinant masTF mature protein was generated in E. Coli, purified, and assessed by Coomassie staining; masTF's identity was successfully verified by western blotting. Analogously to hasTF, masTF induced adhesion of murine endothelial cells (bEnd.3) in a time-dependent fashion. A 15-fold increase over BSA (n = 3; p < 0.0001) was observed as early as 1 hour after the experiment's onset; at 4 hours, bEnd.3 cells exposed to masTF displayed a 37-fold increase over BSA (p < 0.0005). We noted that masTF also induced bEnd.3 cells to display characteristic endothelial morphology, whereas BSA did not. We subsequently used a wound healing assay to ascertain whether masTF promotes directional migration of bEnd.3 cells, and used VEGF (100 ng/mL) as a positive control to assess the degree of potency. Per wound, the area of complete closure generated by masTF (50 nM) was ∼4.9-fold greater than that of the vehicle (n = 3; p < 0.0001), an effect similar to that elicited by VEGF (area of closure ∼7-fold greater than that of the vehicle; p < 0.0001). Microarray analysis of masTF-treated bEnd.3 cells (Affymetrix Gene 1.0 ST platform) revealed upregulation of the genes encoding multiple CXC chemokines, with CXCL2, CXCL10, and CXCL1 topping the list (R = 1.42, 1.37, and 1.32, respectively). Notably, expression of the major adhesion molecule VCAM-1 was also upregulated (R = 1.3), suggesting that masTF may promote interactions between murine endothelial cells and leukocytes. Indeed, we found that stimulating bEnd.3 cells with 50 nM masTF caused J774A.1 cells (murine monocytes/macrophages) to adhere with a 75% increased affinity (n = 3; p = 0.0001 vs. vehicle) when exposed to orbital shear conditions. Depletion of masTF from the medium by Ni-charged beads and denaturation by heat eliminated increased monocyte adhesion, while addition of polymyxin B and non-charged beads had no effect, confirming that the observed biologic phenomena were elicited by the masTF protein. Conclusions. We report, for the first time, that murine asTF appears to possess non-proteolytic biologic properties analogous to those of human asTF, which indicates that the alternatively spliced TF may be a general cell agonist eliciting changes in gene expression via integrin ligation. We are currently investigating whether the endothelial surface molecules interacting with masTF, as well as the intracellular signaling pathways activated by masTF in endothelial cells, are analogous to those engaged by hasTF. Disclosures: No relevant conflicts of interest to declare.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shao-An Wang ◽  
Ming-Jer Young ◽  
Wen-Yih Jeng ◽  
Chia-Yu Liu ◽  
Jan-Jong Hung

AbstractBromodomain (BRD)-containing proteins are important for chromatin remodeling to regulate gene expression. In this study, we found that the deubiquitinase USP24 interacted with BRD through its C-terminus increased the levels of most BRD-containing proteins through increasing their protein stability by the removal of ubiquitin from Lys391/Lys400 of the BRD. In addition, we found that USP24 and BRG1 could regulate each other through regulating the protein stability and the transcriptional activity, respectively, of the other, suggesting that the levels of USP24 and BRG1 are regulated to form a positive feedback loop in cancer progression. Loss of the interaction motif of USP24 eliminated the ability of USP24 to stabilize BRD-containing proteins and abolished the effect of USP24 on cancer progression, including its inhibition of cancer cell proliferation and promotion of cancer cell migration, suggesting that the interaction between USP24 and the BRD is important for USP24-mediated effects on cancer progression. The targeting of BRD-containing proteins has been developed as a strategy for cancer therapy. Based on our study, targeting USP24 to inhibit the levels of BRD-containing proteins may inhibit cancer progression.


Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 5032
Author(s):  
Sophie Mouillet-Richard ◽  
Alexandre Ghazi ◽  
Pierre Laurent-Puig

Beyond its causal involvement in a group of neurodegenerative diseases known as Transmissible Spongiform Encephalopathies, the cellular prion protein PrPC is now taking centre stage as an important contributor to cancer progression in various types of solid tumours. The prion cancer research field has progressively expanded in the last few years and has yielded consistent evidence for an involvement of PrPC in cancer cell proliferation, migration and invasion, therapeutic resistance and cancer stem cell properties. Most recent data have uncovered new facets of the biology of PrPC in cancer, ranging from its control on enzymes involved in immune tolerance to its radio-protective activity, by way of promoting angiogenesis. In the present review, we aim to summarise the body of literature dedicated to the study of PrPC in relation to cancer from the perspective of the hallmarks of cancer, the reference framework defined by Hanahan and Weinberg.


2021 ◽  
Vol 11 ◽  
Author(s):  
Lili Zhang ◽  
Huixiao Chen ◽  
Fengxi He ◽  
Shiqian Zhang ◽  
Aihua Li ◽  
...  

MicroRNAs (miRNAs) play important roles in tumorigenesis by controlling target gene expression. With opposing roles as a tumor suppressor or oncogene, microRNA-320a (miR-320a) was found to participate in tumor genesis and progression and also identified as a potentially useful marker in cancer diagnosis, treatment, and prognosis. To better understand the role of miR-320a in ovarian cancer, we investigated miR-320a expression in epithelial ovarian cancer (EOC) specimens as well as EOC cell lines and analyzed correlations between miR-320a expression and processes associated with EOC progression. The miR-320a level in EOC specimens was found to be associated with ovarian cancer progression and infiltration. Through in vitro and in vivo studies, we found that miR-320a significantly promoted the proliferation, migration, and invasion of EOC cells, and we identified RASSF8 as a target gene of miR-320a that was downregulated in EOC tissues and cell lines. In vitro downregulation of RASSF8 promoted the growth, migration, and invasion of EOC cells. Together these findings indicate that RASSF8 is a direct target of miR-320a, through which miR-320a promotes the progression of EOC.


1993 ◽  
Vol 70 (03) ◽  
pp. 454-457 ◽  
Author(s):  
Claus Bregengaard ◽  
Ole Nordfang ◽  
Per Østergaard ◽  
Jens G L Petersen ◽  
Giorgio Meyn ◽  
...  

SummaryTissue factor pathway inhibitor (TFPI) is a feed back inhibitor of the initial activation of the extrinsic pathway of coagulation. In humans, injection of heparin results in a 2-6 fold increase in plasma TFPI and recent studies suggest that TFPI may be important for the anticoagulant activity of heparin. Full length (FL) TFPI, but not recombinant two-domain (2D) TFPI, has a poly cationic C-terminus showing very strong heparin binding. Therefore, we have investigated if heparin affects the pharmacokinetics of TFPI with and without this C-terminus.FL-TFPI (608 U/kg) and 2D-TFPI (337 U/kg) were injected intravenously in rabbits with and without simultaneous intravenous injections of low molecular weight heparin (450 anti-XaU/kg).Heparin decreased the volume of distribution and the clearance of FL-TFPI by a factor 10-15, whereas the pharmacokinetics of 2D-TFPI were unaffected by heparin. When heparin was administered 2 h following TFPI the recovery of FL-TFPI was similar to that found in the group receiving the two compounds simultaneously, suggesting that the releasable pool of FL-TFPI is removed very slowly in the absence of circulating heparin.


1996 ◽  
Vol 76 (03) ◽  
pp. 361-368 ◽  
Author(s):  
Carrie H Fang ◽  
T-C Lin ◽  
Arabinda Guha ◽  
Yale Nemerson ◽  
William H Konigsberg

SummaryIn an attempt to define sequence elements in human and mouse tissue factor (TF) that are responsible for the species specificity observed in their interaction with human factor VIIa (HVIIa), we constructed human-mouse chimeric TF cDNAs, inserted them into plasmid vectors, and induced their expression in E.coli. Assays for procoagulant activity were carried out with the resulting E. coli lysates using (HVIIa) human and mouse (MVIIa). The ratio of the procoagulant activities, HVIIa/MVIIa, revealed that human TF exon 3 was essential for activity when the TF:VIIa complex was formed with HVIIa. By ligating the maltose binding protein (MBP) gene to TF cDNAs it was possible to construct, express and purify MBP-TF chimeras as well as to estimate their specific activities. With selected MBP-TF chimeras and HVIIa we determined kinetic parameters for the activation of human factor X. Replacement of exon 3 in human TF cDNA with the corresponding exon from mouse TF cDNA resulted in both lower affinity for HVIIa and failure to convert bound HVIIa into a potent protease


1996 ◽  
Vol 75 (05) ◽  
pp. 796-800 ◽  
Author(s):  
Sanne Valentin ◽  
Inger Schousboe

SummaryIn the present study, the interaction between tissue factor pathway inhibitor (TFPI) and phospholipids has been characterized using a microtitre plate assay. TFPI was shown to bind calcium-independently to an acidic phospholipid surface composed of phosphatidylserine, but not a surface composed of the neutral phosphatidylcholine. The interaction was demonstrated to be dependent on the presence of the TFPI C-terminus. The presence of heparin (1 U/ml, unfractionated) was able to significantly reduce the binding of TFPI to phospholipid. The interaction of TFPI with phosphatidylserine was significantly decreased in the presence of calcium, but this was counteracted, and even enhanced, following complex formation of TFPI with factor Xa prior to incubation with the phospholipid surface. Moreover, a TFPI variant, not containing the third Kunitz domain and the C-terminus, was unable to bind to phospholipid. However, following the formation of a TFPI/factor Xa-complex this TFPI variant was capable of interacting with the phospholipid surface. This indicates that the role of factor Xa as a TFPI cofactor, at least in part, is to mediate the binding of TFPI to the phospholipid surface.


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