Said Rahim

Small molecule inhibitors of ezrin inhibit the invasive phenotype of osteosarcoma cells.

Ezrin is a multifunctional protein that connects the actin cytoskeleton to the extracellular matrix through transmembrane proteins. High ezrin expression is associated with lung metastasis and poor survival in cancer. We screened small molecule libraries for compounds that directly interact with ezrin protein using surface plasmon resonance to identify lead compounds. The secondary functional assays used for lead compound selection included ezrin phosphorylation as measured by immunoprecipitation and in vitro kinase assays, actin binding, chemotaxis, invasion into an endothelial cell monolayer, zebrafish and Xenopus embryonic development, mouse lung organ culture and an in vivo lung metastasis model. Two molecules, NSC305787 and NSC668394, that directly bind to ezrin with low micromolar affinity were selected based on inhibition of ezrin function in multiple assays. They inhibited ezrin phosphorylation, ezrin–actin interaction and ezrin-mediated motility of osteosarcoma (OS) cells in culture. NSC305787 mimicked the ezrin morpholino phenotype, and NSC668394 caused a unique developmental defect consistent with reduced cell motility in zebrafish. Following tail vein injection of OS cells into mice, both molecules inhibited lung metastasis of ezrin-sensitive cells, but not ezrin-resistant cells. The small molecule inhibitors NSC305787 and NSC668394 demonstrate a novel targeted therapy that directly inhibits ezrin protein as an approach to prevent tumor metastasis.

A real-time electrical impedance based technique to measure invasion of endothelial cell monolayer by cancer cells.

Metastatic dissemination of malignant cells requires degradation of basement membrane, attachment of tumor cells to vascular endothelium, retraction of endothelial junctions and finally invasion and migration of tumor cells through the endothelial layer to enter the bloodstream as a means of transport to distant sites in the host(1-3). Once in the circulatory system, cancer cells adhere to capillary walls and extravasate to the surrounding tissue to form metastatic tumors(4,5). The various components of tumor cell-endothelial cell interaction can be replicated in vitro by challenging a monolayer of human umbilical vein endothelial cells (HUVEC) with cancer cells. Studies performed with electron and phase-contrast microscopy suggest that the in vitro sequence of events fairly represent the in vivo metastatic process(6). Here, we describe an electrical-impedance based technique that monitors and quantifies in real-time the invasion of endothelial cells by malignant tumor cells. Giaever and Keese first described a technique for measuring fluctuations in impedance when a population of cells grow on the surface of electrodes(7,8). The xCELLigence instrument, manufactured by Roche, utilizes a similar technique to measure changes in electrical impedance as cells attach and spread in a culture dish covered with a gold microelectrode array that covers approximately 80% of the area on the bottom of a well. As cells attach and spread on the electrode surface, it leads to an increase in electrical impedance(9-12). The impedance is displayed as a dimensionless parameter termed cell-index, which is directly proportional to the total area of tissue-culture well that is covered by cells. Hence, the cell-index can be used to monitor cell adhesion, spreading, morphology and cell density. The invasion assay described in this article is based on changes in electrical impedance at the electrode/cell interphase, as a population of malignant cells invade through a HUVEC monolayer (Figure 1). The disruption of endothelial junctions, retraction of endothelial monolayer and replacement by tumor cells lead to large changes in impedance. These changes directly correlate with the invasive capacity of tumor cells, i.e., invasion by highly aggressive cells lead to large changes in cell impedance and vice versa. This technique provides a two-fold advantage over existing methods of measuring invasion, such as boyden chamber and matrigel assays: 1) the endothelial cell-tumor cell interaction more closely mimics the in vivo process, and 2) the data is obtained in real-time and is more easily quantifiable, as opposed to end-point analysis for other methods.

A small molecule inhibitor of ETV1, YK-4-279, prevents prostate cancer growth and metastasis in a mouse xenograft model.

Background The erythroblastosis virus E26 transforming sequences (ETS) family of transcription factors consists of a highly conserved group of genes that play important roles in cellular proliferation, differentiation, migration and invasion. Chromosomal translocations fusing ETS factors to promoters of androgen responsive genes have been found in prostate cancers, including the most clinically aggressive forms. ERG and ETV1 are the most commonly translocated ETS proteins. Over-expression of these proteins in prostate cancer cells results in a more invasive phenotype. Inhibition of ETS activity by small molecule inhibitors may provide a novel method for the treatment of prostate cancer. Methods and Findings We recently demonstrated that the small molecule YK-4-279 inhibits biological activity of ETV1 in fusion-positive prostate cancer cells leading to decreased motility and invasion in-vitro. Here, we present data from an in-vivo mouse xenograft model. SCID-beige mice were subcutaneously implanted with fusion-positive LNCaP-luc-M6 and fusion-negative PC-3M-luc-C6 tumors. Animals were treated with YK-4-279, and its effects on primary tumor growth and lung metastasis were evaluated. YK-4-279 treatment resulted in decreased growth of the primary tumor only in LNCaP-luc-M6 cohort. When primary tumors were grown to comparable sizes, YK-4-279 inhibited tumor metastasis to the lungs. Expression of ETV1 target genes MMP7, FKBP10 and GLYATL2 were reduced in YK-4-279 treated animals. ETS fusion-negative PC-3M-luc-C6 xenografts were unresponsive to the compound. Furthermore, YK-4-279 is a chiral molecule that exists as a racemic mixture of R and S enantiomers. We established that (S)-YK-4-279 is the active enantiomer in prostate cancer cells. Conclusion Our results demonstrate that YK-4-279 is a potent inhibitor of ETV1 and inhibits both the primary tumor growth and metastasis of fusion positive prostate cancer xenografts. Therefore, YK-4-279 or similar compounds may be evaluated as a potential therapeutic tool for treatment of human prostate cancer at different stages.

Synthesis and Structure−Activity Relationship Studies of Small Molecule Disruptors of EWS-FLI1 Interactions in Ewing's Sarcoma

EWS-FLI1 is an oncogenic fusion protein implicated in the development of Ewing’s sarcoma family tumors (ESFT). Using our previously reported lead compound 2 (YK-4-279), we designed and synthesized a focused library of analogues. The functional inhibition of the analogues was measured by an EWS-FLI1/NR0B1 reporter luciferase assay and a paired cell screening approach measuring effects on growth inhibition for human cells containing EWS-FLI1 (TC32 and TC71) and control PANC1 cell lines devoid of the oncoprotein. Our data revealed that substitution of electron donating groups at the para-position on the phenyl ring was the most favorable for inhibition of EWS-FLI1 by analogs of 2. Compound 9u (with a dimethylamino substitution) was the most active inhibitor with GI50 = 0.26 ± 0.1 μM. Further, a correlation of growth inhibition (EWS-FLI1 expressing TC32 cells) and the luciferase reporter activity was established (R2 = 0.84). Finally, we designed and synthesized a biotinylated analogue and determined the binding affinity for recombinant EWS-FLI1 (Kd = 4.8 ± 2.6 μM).

Inorganic polyphosphates are important for cell survival and motility of human skin keratinocytes

CCL22 in keratinocytes may be an effective target for the treatment of inflammatory skin diseases (7, S2). These preclinical and clinical studies also suggest that TARC/CCL17 and MDC/CCL22 are important molecules involved in the pathogenesis of AD. In this study, crocin exerted an inhibitory effect on PI3K/Akt, ERK1/ 2 and NF-jB activation (8, S3). Pretreatment with crocin clearly suppressed mRNA expression and release of TARC/CCL17 and MDC/CCL22 in TNF-a/IFN-c-stimulated HaCaT cells. NF-jB and JAK/STAT signalling pathways are involved in the regulation of TARC/CCL17 and MDC/CCL22 release in HaCaT cells. In addition, the promoters of TARC/CCL17 and MDC/CCL22 contain NF-jBand STAT1-binding sites, indicating that these transcription factors may be involved in the modulation of TARC/ CCL17 and MDC/CCL22. TNF-a/IFN-c stimulation in HaCaT cells activates several intracellular MAPK signalling pathways (3). TNF-a activates the phosphatidylinositol (PI) 3-kinase/Akt pathway, and activation of the PI3K/Akt pathway induces NF-jB activation in HaCaT cells (9). In agreement with these reports, our results showed that ERK-MAPK/PI3K/Akt mediates the activation of NF-jB and STAT1 as well as expressions of TARC/CCL17 and MDC/CCL22 in TNF-a/IFN-c-stimulated HaCaT cells. We observed that crocin blocked TNF-a/IFN-c-induced TARC/CCL17 and MDC/CCL22 release by inhibiting ERK/PI3K/Akt signalling pathways that lead to the activation of NF-jB and JAK/STAT signalling pathways. In conclusion, this study provides evidence that crocin inhibits TNF-a/IFN-c-induced expression of TARC/CCL17 and MDC/CCL22 gene via suppression of ERK/MAPK/NF-jB/STAT signalling pathways in HaCaT cells. A better understanding of the mechanism by which crocin modulates expression of Th2 chemokines would provide a molecular basis for developing its clinical application against inflammatory skin diseases such as AD. Acknowledgements This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2013R1A1A106 2064). Author contribution Ji-Hyun Park designed the study, performed the research and wrote the paper; Ki Yong Lee contributed essential reagents; Byoungduck Park and Jaewoo Yoon supervised the study. Conflict of interests The authors have declared no conflicting interests. Supporting Information

Abstract 5453: YK-4-279 inhibits ETS-positive prostate cancer cell metastasis in a mouse xenograft model.

Chromosomal translocations involving the ETS family of transcription factors are found in a majority of prostate cancers, including the most clinically aggressive forms. These translocations produce a chimeric gene, which fuses the promoter region of an androgen responsive gene to the coding region of ETS factors, most frequently ETV1 or ERG. Over-expression of ETS factors in prostate cancer cells results in a more invasive phenotype. The high prevalence of these rearrangements, and their biological significance represents a novel therapeutic target for the treatment of prostate cancer. We recently demonstrated that the small molecule YK-4-279 inhibits ERG and ETV1 biological activity in fusion-positive prostate cancer cells leading to decreased motility and invasion in-vitro. Here we present our findings in an in-vivo mouse xenograft model. SCID-beige mice were subcutaneously injected with LNCaP and PC-3 xenografts. Mice were treated with YK-4-279 and its effect on primary tumor size and lung metastasis was observed. YK-4-279 treatment resulted in reduced metastasis of the tumor from primary site to lungs. YK-4-279 also affected expression of ETV1 target genes such as MMP7 and MMP13. ETS fusion-negative PC-3 xenografts were unresponsive to YK-4-279. Our results demonstrate that YK-4-279 decreases tumor growth and inhibits metastasis in fusion-positive prostate cancer cell xenografts. Therefore, YK-4-279 may have an impact on preventing metastasis in prostate cancer patients, which is a leading cause of death. Citation Format: Said Rahim, Sarah Justvig, Sung-Hyeok Hong, Yali Kong, Milton L. Brown, Colm Morrissey, Jeffrey A. Toretsky, Aykut Uren. YK-4-279 inhibits ETS-positive prostate cancer cell metastasis in a mouse xenograft model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5453. doi:10.1158/1538-7445.AM2013-5453

Abstract 2949: YK-4-279 is a small molecule inhibitor of ETV1 and inhibits metastasis in a mouse model

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA The erythroblastosis virus E26 transforming sequences (ETS) family of transcription factors consists of a highly conserved group of genes that play important roles in cellular proliferation, differentiation, migration and invasion. Chromosomal translocations fusing ETS factors to promoters of androgen responsive genes have been found in a majority of prostate cancers, including the most clinically aggressive forms. ERG and ETV1 are the most commonly translocated ETS proteins. Over-expression of these proteins in prostate cancer cells results in a more invasive phenotype. The high prevalence of these rearrangements, and their biological significance represents a novel therapeutic target for the treatment of prostate cancer. We recently demonstrated that the small molecule YK-4-279 inhibits ERG and ETV1 biological activity in fusion-positive prostate cancer cells leading to decreased motility and invasion in-vitro. Here, we present our findings in an in-vivo mouse xenograft model. SCID-beige mice were subcutaneously implanted with fusion-positive LNCaP and fusion-negative PC-3 tumors. Animals were treated with YK-4-279 and its effect on tumor size, lung metastasis and survival were observed. YK-4-279 treatment resulted in decreased tumor size in the LNCaP cohort only. A reduction in tumor metastasis to the lungs was observed in compound treated LNCaP animals with comparable tumor sizes. YK-4-279 also increased survival in LNCaP mice. Expression of ETV1 target genes MMP7, FKBP10 and GLYATL2 was reduced as well. ETS fusion-negative PC-3 xenografts were unresponsive to the compound. YK-4-279 is a chiral molecule that exists as a racemic mixture of R and S enantiomers. As part of this study, we also established that (S) -YK-4-279 is the active enantiomer in prostate cancer cells. (S) -YK-4-279 binds to ETV1 with comparable kinetics as the racemic mixture and inhibits ETV1 activity. (R) -YK-4-279 does not demonstrate ETV1 binding or inhibition. Our results demonstrate that YK-4-279 is a potent inhibitor of ETV1 and should be further evaluated for its clinical applications in prostate cancer. Citation Format: Said Rahim, Sarah Justvig, Sung-Hyeok Hong, Perrer Tosso, Haydar Celik, Yasemin Sayedigar-Kont, Milton Brown, Colm Morrissey, Jeffrey Toretsky, Aykut Uren. YK-4-279 is a small molecule inhibitor of ETV1 and inhibits metastasis in a mouse model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2949. doi:10.1158/1538-7445.AM2014-2949

Abstract 4505: Development of small molecules to target ezrin as anti-metastatic agents

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL The most common cause for mortality in osteosarcoma (OS) is respiratory failure due to metastasis to lungs. Thus targeting underlying molecular events that lead to metastasis can provide a significant benefit to patients with fatal metastatic disease. Accumulating evidence from experimental animal models and human cases suggests that ezrin is a key factor in the metastasis of OS cells. Ezrin is a multifunctional protein that connects the actin cytoskeleton to extracellular matrix through transmembrane proteins. We screened small molecule libraries for compounds that directly interact with ezrin protein. Two small molecules that directly bind to ezrin with low micromolar affinity were selected based on inhibiting ezrin function in multiple assays. They inhibited ezrin phosphorylation, ezrin-actin interaction, and ezrin mediated motility of OS cells in culture. These compounds were unique in their mechanism of action such that they inhibited in vitro phosphorylation of ezrin by protein kinase C (PKC) by binding to the substrate not by inhibiting the kinase activity of the enzyme. PKC was able to phosphorylate other substrates in the presence of these novel ezrin inhibitors. They also mimicked the ezrin morpholino phenotype and caused a unique developmental defect consistent with reduced cell motility in zebrafish. Following tail vein injection of osteosarcoma cells to mice, both molecules inhibited lung metastasis of ezrin-sensitive cells, but not ezrin-resistant cells. These two molecules demonstrate a novel targeted therapy that directly inhibits ezrin protein as an approach to prevent tumor metastasis in osteosarcoma and other tumors with elevated ezrin in their metastatic subclones. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4505. doi:10.1158/1538-7445.AM2011-4505

Abstract 663: YK-4-279 inhibits ERG and ETV1 mediated prostate cancer cell invasion

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Chromosomal translocations involving the ETS family of transcription factors are found in a majority of prostate cancers, including the most clinically aggressive forms. These translocations produce a chimeric gene, which fuses the promoter region of an androgen responsive gene, such as TMPRSS2, to the coding region of ETS factors, most frequently ETV1 or ERG. Over-expression of ETS factors in prostate cancer cells results in a more invasive phenotype. The high prevalence of these rearrangements, and their biological significance represents a novel therapeutic target for the treatment of prostate cancer. We recently reported the development of YK-4-279, a small molecule inhibitor of EWS-FLI1 oncoprotein in Ewings Sarcoma. ERG and ETV1 belong to the same class of ETS factors as FLI1. Due to the close homology of FLI1 with ERG and ETV1, we tested the ability of YK-4-279 to inhibit ETS biological activity in prostate cell-lines such as VCaP and LNCaP that demonstrate androgen dependent ERG and ETV1 expression, respectively. YK-4-279 inhibited ERG and ETV1 mediated transcription of target genes such as PLAU, PLAT, ADAM19 and MMP-13, which are involved in breakdown of the extracellular matrix and metastasis. YK-4-279 reduced the motility and invasive phenotype of ETV1-fusion positive LNCaP cells and ERG fusion-positive VCaP cells in in vitro invasion assays. However, ETS fusion-negative PC-3 cells were unresponsive to YK-4-279. ERG knockdown in VCaP cells resulted in a loss of drug responsiveness. Transient ERG expression in PC-3 cells resulted in an increased invasive phenotype, which was reduced by YK-4-279. Our results demonstrate that YK-4-279 inhibits ERG and ETV1 biological activity in fusion-positive prostate cancer cells leading to decreased motility and invasion. Therefore, YK-4-279 may have an impact on metastasis in prostate cancer, which is a leading cause of death, and it may be further evaluated for its clinical applications in prostate cancer, in addition to Ewings sarcoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 663. doi:10.1158/1538-7445.AM2011-663