GANT 58

GANT 58 is an antagonist of GLI that inhibits GLI1-induced transcription with an IC50 value of 5 μM [1].

GLI1 is a human glioblastoma isolated protein which belongs to GLI protein family. GLI proteins act as effectors in Hedgehog signaling pathway and get involved in cell proliferation, determination and patterning during embryo development.

GANT 58 is considered to inhibit GLI1-mediated gene trans-activation with a high selectivity for Hedgehog signaling pathway. When TNF signaling/NFkB activation, glucocorticoid, receptor gene transactivation, and the Ras-Raf-Mek-Mapk cascade were treated with GANT 58, no inhibition was observed. When SAG-treated shh-L2 cells were treated with 10 μM GANT 58 for 48 hr, the reduction of Hedgehog pathway signaling was observed, whereas Gli1 mRNA level reduction was induced by the treatment of 10 μM GANT 58 for 2-3 days. Indeed, GANT 58 was confirmed as inhibitor of Hedgehog signaling pathway downstream Sufu and Smo [1]. Furthermore, GANT 58 treatments for 48 hr resulted in the significant reduction of cell viability in a dose-dependent manner for CCRFeCEM, CEM7e14, CEM1e15 and Jurkat cells. When CCRFeCEM cells were treated with 10 μM GANT 58 for 48 hr, the percentage of cells in G1/S phase increased whereas the percentage in G2/M phase decreased [2].

In mouse model with xenograft, daily s.c. injection of GANT 58 resulted in significant suppression of tumor cell growth. 50 mg/kg/d GANT 58 injections for 18 days induced the suppression of additional xenograft growth and restrict the increase of tumor size. No side effects were observed during the treatment [1].

References:
[1] Lauth M, Bergstr?m ?sa, Shimokawa T, Toftg?rd R.  Inhibition of GLI-mediated transcription and tumor cell growth by small-molecule antagonists.?Proceedings of the National Academy of Sciences of the United States of America. 2007,104(20):8455-8460.
[2] Hou X, Chen X, Zhang P, et al.  Inhibition of hedgehog signaling by GANT58 induces apoptosis and shows synergistic antitumor activity with AKT inhibitor in acute T cell leukemia cells. Biochimie. 2014, 101:50-9

Regulation of angiogenic behaviors by oxytocin receptor through Gli1-indcued transcription of HIF-1alpha in human umbilical vein endothelial cells.[Pubmed:28445928]

Biomed Pharmacother. 2017 Jun;90:928-934.

Angiogenesis is a dynamic hypoxia-stimulated process playing a key role in tissue growth and repair under various pathophysiological circumstances. Abnormal angiogenesis contributes to the pathogenesis of many human diseases. Oxytocin receptor is a classical G-protein-coupled receptor expressed on endothelial cells. The present study was aimed to investigate how oxytocin receptor regulated the angiogenic behaviors of human umbilical vein endothelial cells (HUVECs). We found that oxytocin at 0.1muM significantly increased cell proliferation, upregulated the mRNA and protein expression of CD31 and vWF (two important endothelial markers), and enhanced the tuber formation capacity in HUVECs. However, oxytocin receptor inhibitor atosiban at 10muM significantly suppressed these angiogenic properties of HUVECs. Additionally, hypoxia-inducible factor-1alpha (HIF-1alpha) inhibitor PX-478 at 20muM also remarkably inhibited the angiogenic properties of HUVECs. We further found that atosiban at 10muM significantly repressed the promoter activity of HIF-1alpha and reduced the mRNA and protein expression of HIF-1alpha in HUVECs. Moreover, pharmacological inhibition of HIF-1alpha by PX-478 at 20muM abolished oxytocin-enhanced angiogenic properties of HUVECs. Finally, transcription factor Gli1 inhibitor GANT-58 at 5muM significantly abolished oxytocin-induced mRNA and protein expression of HIF-1alpha, while the nuclear abundance of Gli1 was significantly reduced by atosiban at 10muM, but was increased by oxytocin at 0.1muM in HUVECs. GANT-58 at 5muM also significantly abolished oxytocin-enhanced angiogenic properties of HUVECs. Altogether, these discoveries suggested that oxytocin receptor signaling promoted the angiogenic behaviors of HUVECs via Gli1-indcued transcription of HIF-1alpha. We provided novel molecular insights into endothelial cell-mediated angiogenesis.

Hedgehog pathway plays a vital role in HIV-induced epithelial-mesenchymal transition of podocyte.[Pubmed:28159470]

Exp Cell Res. 2017 Mar 15;352(2):193-201.

HIV-associated nephropathy (HIVAN) is characterized by heavy proteinuria, rapidly progressive renal failure, and distinct morphological features in the kidney. HIV-induced epithelial-mesenchymal transition (EMT) is critically important for the progression of kidney injury. In this study, we tested the role of hedgehog pathway in the HIV-induced EMT and fibrosis of kidney. We used the Tg26 mice, the abundantly used HIVAN mouse model, to investigate the activation of hedgehog pathway by HIV. Western blotting and real time PCR results showed that renal tissue expression of hedgehog pathway related molecules, including hedgehog homologous (Shh, Ihh, Dhh), PTCH, and Gli1, were increased in HIVAN (Tg26) mice; while immunofluorescent staining displayed localization PTCH expression in podocytes. For in vitro studies, we used recombinant sonic hedgehog (Shh) and HIV for their expression by podocytes. Both the methods activated the hedgehog pathway, enhanced the expression of EMT markers, and decreased impermeability. Overexpression of Gli1 by human podocytes also augmented their expression of EMT markers. On the other hand, the blockade of hedgehog pathway with GANT 58, a specific blocker for Gli1-induced transcription, dramatically decreased HIV-induced podocyte EMT and permeability. These results indicate that hedgehog pathway plays an important role in HIV-induced podocyte injury. The present study provides mechanistical insight into a new target for therapeutic strategy.

Integrated Assessment of Pharmacological and Nutritional Cardiovascular Risk Management: Blood Pressure Control in the DIAbetes and LifEstyle Cohort Twente (DIALECT).[Pubmed:28684676]

Nutrients. 2017 Jul 6;9(7). pii: nu9070709.

Cardiovascular risk management is an integral part of treatment in Type 2 Diabetes Mellitus (T2DM), and requires pharmacological as well as nutritional management. We hypothesize that a systematic assessment of both pharmacological and nutritional management can identify targets for the improvement of treatment quality. Therefore, we analysed blood pressure (BP) management in the DIAbetes and LifEstyle Cohort Twente (DIALECT). DIALECT is an observational cohort from routine diabetes care, performed at the ZGT Hospital (Almelo and Hengelo, The Netherlands). BP was measured for 15 minutes with one minute intervals. Sodium and potassium intake was derived from 24-hour urinary excretion. We determined the adherence to pharmacological and non-pharmacological guidelines in patients with BP on target (BP-OT) and BP not on target (BP-NOT). In total, 450 patients were included from August 2009 until January 2016. The mean age was 63 +/- 9 years, and the majority was male (58%). In total, 53% had BP-OT. In those with BP-NOT, pharmacological management was suboptimal (zero to two antihypertensive drugs) in 62% of patients, and nutritional guideline adherence was suboptimal in 100% of patients (only 8% had a sodium intake on target, 66% had a potassium intake on target, 3% had a sodium-to-potassium ratio on target, and body mass index was <30 kg/m(2) in 35%). These data show pharmacological undertreatment and a low adherence to nutritional guidelines. Uncontrolled BP is common in T2DM, and our data show a window of opportunity for improving BP control, especially in nutritional management. To improve treatment quality, we advocate to incorporate the integrated monitoring of nutritional management in quality improvement cycles in routine care.

Canonical hedgehog signalling regulates hepatic stellate cell-mediated angiogenesis in liver fibrosis.[Pubmed:28052321]

Br J Pharmacol. 2017 Mar;174(5):409-423.

BACKGROUND AND PURPOSE: Hepatic stellate cells (HSCs) are liver-specific pericytes regulating angiogenesis during liver fibrosis. We aimed to elucidate the mechanisms by which hedgehog signalling regulated HSC angiogenic properties and to validate the therapeutic implications. EXPERIMENTAL APPROACH: Rats and mice were treated with carbon tetrachloride for in vivo evaluation of hepatic angiogenesis and fibrotic injury. Diversified molecular approaches including real-time PCR, Western blot, luciferase reporter assay, chromatin immunoprecipitation, electrophoretic mobility shift assay and co-immunoprecipitation were used to investigate the underlying mechanisms in vitro. KEY RESULTS: Angiogenesis was concomitant with up-regulation of Smoothened (SMO) and hypoxia inducible factor-1alpha (HIF-1alpha) in rat fibrotic liver. The SMO inhibitor cyclopamine and Gli1 inhibitor GANT-58 reduced expression of VEGF and angiopoietin 1 in HSCs and suppressed HSC tubulogenesis capacity. HIF-1alpha inhibitor PX-478 suppressed HSC angiogenic behaviour, and inhibition of hedgehog decreased HIF-1alpha expression. Furthermore, heat shock protein 90 (HSP90) was characterized as a direct target gene of canonical hedgehog signalling in HSCs. HSP90 inhibitor 17-AAG reduced HSP90 binding to HIF-1alpha, down-regulated HIF-1alpha protein abundance and decreased HIF-1alpha binding to DNA. 17-AAG also abolished 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) (a SMO agonist)-enhanced HSC angiogenic properties. Finally, the natural compound ligustrazine was found to inhibit canonical hedgehog signalling leading to suppressed angiogenic properties of HSCs in vitro and ameliorated liver fibrosis and sinusoidal angiogenesis in mice. CONCLUSION AND IMPLICATIONS: We have provided evidence that the canonical hedgehog pathway controlled HSC-mediated liver angiogenesis. Selective inhibition of HSC hedgehog signalling could be a promising therapeutic approach for hepatic fibrosis.

The Unyvero P55 'sample-in, answer-out' pneumonia assay: A performance evaluation.[Pubmed:29021968]

Biomol Detect Quantif. 2017 Jun 28;13:1-6.

BACKGROUND: O'Neill's recent Review on Antimicrobial Resistance expressed the view that by 2020 high-income countries should make it mandatory to support antimicrobial prescribing with rapid diagnostic evidence whenever possible. METHODS: Routine microbiology diagnosis of 95 respiratory specimens from patients with severe infection were compared with those generated by the Unyvero P55 test, which detects 20 pathogens and 19 antimicrobial resistance markers. Supplementary molecular testing for antimicrobial resistance genes, comprehensive culture methodology and 16S rRNA sequencing were performed. RESULTS: Unyvero P55 produced 85 valid results, 67% of which were concordant with those from the routine laboratory. Unyvero P55 identified more potential pathogens per specimen than routine culture (1.34 vs. 0.47 per specimen). Independent verification using 16S rRNA sequencing and culture (n = 10) corroborated 58% of additional detections compared to routine microbiology. Overall the average sensitivity for organism detection by Unyvero P55 was 88.8% and specificity was 94.9%. While Unyvero P55 detected more antimicrobial resistance markers than routine culture, some instances of phenotypic resistance were missed. CONCLUSIONS: The Unyvero P55 is a rapid pathogen detection test for lower respiratory specimens, which identifies a larger number of pathogens than routine microbiology. The clinical significance of these additional organisms is yet to be determined. Further studies are required to determine the effect of the test in practise on antimicrobial prescribing and patient outcomes.

GLI1 is a direct transcriptional target of EWS-FLI1 oncoprotein.[Pubmed:19189974]

J Biol Chem. 2009 Apr 3;284(14):9074-82.

Ewing sarcoma family of tumors (ESFT) is an undifferentiated neoplasm of the bone and soft tissue. ESFT is characterized by a specific chromosomal translocation occurring between chromosome 22 and (in most cases) chromosome 11, which generates an aberrant transcription factor, EWS-FLI1. The function of EWS-FLI1 is essential for the maintenance of ESFT cell survival and tumorigenesis. The Hedgehog pathway is activated in several cancers. Oncogenic potential of the Hedgehog pathway is mediated by increasing the activity of the GLI family of transcription factors. Recent evidence suggests that EWS-FLI1 increases expression of GLI1 by an unknown mechanism. Our data from chromatin immunoprecipitation and promoter reporter studies indicated GLI1 as a direct transcriptional target of EWS-FLI1. Expression of EWS-FLI1 in non-ESFT cells increased GLI1 expression and GLI-dependent transcription. We also detected high levels of GLI1 protein in ESFT cell lines. Pharmacological inhibition of GLI1 protein function decreased proliferation and soft agar colony formation of ESFT cells. Our results establish GLI1 as a direct transcriptional target of EWS-FLI1 and suggest a potential role for GLI1 in ESFT tumorigenesis.

GLI1 is a central mediator of EWS/FLI1 signaling in Ewing tumors.[Pubmed:19859563]

PLoS One. 2009 Oct 27;4(10):e7608.

The Ewing Sarcoma Family Tumors (ESFT) consist of the classical pathologic entities of Ewing Sarcoma and peripheral Primitive Neuroectodermal Tumor. Occurring largely in the childhood through young adult years, these tumors have an unsurpassed propensity for metastasis and have no defined cell of origin. The biology of these aggressive malignancies centers around EWS/FLI1 and related EWS/ETS chimeric transcription factors, which are largely limited to this tumor class. Much progress has been made in the identification of a network of loci whose expression is modulated by EWS/FLI1 and its congeners. To date, little progress has been made in reconstructing the sequence of direct and indirect events that produce this network of modulated loci. The recent identification of GLI1 as an upregulated target of EWS/ETS transcription factors suggests a target which may be a more central mediator in the ESFT signaling network. In this paper, we further define the relationship of EWS/FLI1 expression and GLI1 upregulation in ESFT. This relationship is supported with data from primary tumor specimens. It is consistently observed across multiple ESFT cell lines and with multiple means of EWS/FLI1 inhibition. GLI1 inhibition affects tumor cell line phenotype whether shRNA or endogenous or pharmacologic inhibitors are employed. As is seen in model transformation systems, GLI1 upregulation by EWS/FLI1 appears to be independent of Hedgehog stimulation. Consistent with a more central role in ESFT pathogenesis, several known EWS/FLI1 targets appear to be targeted through GLI1. These findings further establish a central role for GLI1 in the pathogenesis of Ewing Tumors.

Inhibition of GLI-mediated transcription and tumor cell growth by small-molecule antagonists.[Pubmed:17494766]

Proc Natl Acad Sci U S A. 2007 May 15;104(20):8455-60.

The developmentally important Hedgehog (Hh) signaling pathway has recently been implicated in several forms of solid cancer. Current drug development programs focus on targeting the protooncogene Smoothened, a key transmembrane pathway member. These drug candidates, albeit promising, do not address the scenario in which pathway activation occurs downstream of Smoothened, as observed in cases of medulloblastoma, glioma, pericytoma, breast cancer, and prostate cancer. A cellular screen for small-molecule antagonists of GLI-mediated transcription, which constitutes the final step in the Hh pathway, revealed two molecules that are able to selectively inhibit GLI-mediated gene transactivation. We provide genetic evidence of downstream pathway blockade by these compounds and demonstrate the ineffectiveness of upstream antagonists such as cyclopamine in such situations. Mechanistically, both inhibitors act in the nucleus to block GLI function, and one of them interferes with GLI1 DNA binding in living cells. Importantly, the discovered compounds efficiently inhibited in vitro tumor cell proliferation in a GLI-dependent manner and successfully blocked cell growth in an in vivo xenograft model using human prostate cancer cells harboring downstream activation of the Hh pathway.