Pyrrole Imidazole Research Articles

Structural Studies of a Complex of a CAG/CTG Repeat Sequence-Specific Binding Molecule and A-A-Mismatch-Containing DNA.

Triplet repeat diseases are caused by the abnormal elongation of repeated sequences comprising three bases. In particular, the elongation of CAG/CTG repeat sequences is thought to result in conditions such as Huntington's disease and myotonic dystrophy type 1. Although the causes of these diseases are known, fundamental treatments have not been established, and specific drugs are expected to be developed. Pyrrole imidazole polyamide (PIP) is a class of molecules that binds to the minor groove of the DNA duplex in a sequence-specific manner; because of this property, it shows promise in drug discovery applications. Earlier, it was reported that PIP designed to bind CAG/CTG repeat sequences suppresses the genes that cause triplet repeat diseases. In this study, we performed an X-ray crystal structure analysis of a complex of double-stranded DNA containing A-A mismatched base pairs and a cyclic-PIP that binds specifically to CAG/CTG sequences. Furthermore, the validity and characteristics of this structure were analyzed using in silico molecular modeling, ab initio energy calculations, gel electrophoresis, and surface plasmon resonance. With our direct observation using atomic force microscopy and DNA origami, we revealed that the PIP caused structural changes in the DNA strands carrying the expanded CAG/CTG repeat. Overall, our study provides new insight into PIP from a structural perspective.

Development of multifunctional pyrrole-imidazole polyamides that increase hepatocyte growth factor and suppress transforming growth factor-β1

PurposeThe DNA recognition peptide compounds pyrrole-imidazole (PI) polyamides bind to the minor groove and can block the binding of transcription factors to target sequences. To develop more PI polyamides as potential treatments for fibrotic diseases, including chronic renal failure, we developed multifunctional PI polyamides that increase hepatocyte growth factor (HGF) and decrease transforming growth factor (TGF)-β1. MethodsWe designed seven PI polyamides (HGF-1 to HGF-7) that bind to the chicken ovalbumin upstream promoter transcription factor-1 (COUP-TF1) binding site of the HGF promoter sequence. We selected PI polyamides that increase HGF and suppress TGF-β1 in human dermal fibroblasts (HDFs). FindingsGel shift assays showed that HGF-2 and HGF-4 bound the appropriate dsDNAs. HGF-2 and HGF-4 significantly inhibited the TGF-β1 mRNA expression in HDFs stimulated by phorbol 12-myristate 13-acetate. HGF-2 and HGF-4 significantly inhibited the TGF-β1 protein expression in HDFs with siRNA targeting HGF, indicating that HGF-2 and HGF-4 directly inhibited the expression of TGF-β1. ConclusionThe designed and synthetic HGF PI polyamides targeting the HGF promoter, which increased the expression of HGF and suppressed the expression of TGF-β, will be a potential practical medicine for fibrotic diseases, including progressive renal diseases.

Novel Auger-Electron-Emitting 191Pt-Labeled Pyrrole-Imidazole Polyamide Targeting MYCN Increases Cytotoxicity and Cytosolic dsDNA Granules in MYCN-Amplified Neuroblastoma.

Auger electrons can cause nanoscale physiochemical damage to specific DNA sites that play a key role in cancer cell survival. Radio-Pt is a promising Auger-electron source for damaging DNA efficiently because of its ability to bind to DNA. Considering that the cancer genome is maintained under abnormal gene amplification and expression, here, we developed a novel 191Pt-labeled agent based on pyrrole-imidazole polyamide (PIP), targeting the oncogene MYCN amplified in human neuroblastoma, and investigated its targeting ability and damaging effects. A conjugate of MYCN-targeting PIP and Cys-(Arg)3-coumarin was labeled with 191Pt via Cys (191Pt-MYCN-PIP) with a radiochemical purity of >99%. The binding potential of 191Pt-MYCN-PIP was evaluated via the gel electrophoretic mobility shift assay, suggesting that the radioagent bound to the DNA including the target sequence of the MYCN gene. In vitro assays using human neuroblastoma cells showed that 191Pt-MYCN-PIP bound to DNA efficiently and caused DNA damage, decreasing MYCN gene expression and MYCN signals in in situ hybridization analysis, as well as cell viability, especially in MYCN-amplified Kelly cells. 191Pt-MYCN-PIP also induced a substantial increase in cytosolic dsDNA granules and generated proinflammatory cytokines, IFN-α/β, in Kelly cells. Tumor uptake of intravenously injected 191Pt-MYCN-PIP was low and its delivery to tumors should be improved for therapeutic application. The present results provided a potential strategy, targeting the key oncogenes for cancer survival for Auger electron therapy.

Total Synthesis of Nagelamide W.

Herein, we report the total synthesis of nagelamide W (1), a pyrrole imidazole alkaloid of the nagelamide family isolated in 2013. The key approach in this work involves the construction of the 2-aminoimidazoline core of nagelamide W from alkene 6 through a cyanamide bromide intermediate. The synthesis of nagelamide W was accomplished with an overall yield of 6.0%.

Pyrrole–Imidazole Polyamides – A Frontrunner in Nucleic Acid‐Based Small Molecule Drugs

AbstractThe remarkable success of messenger RNA vaccines against the ongoing coronavirus‐2019 (COVID‐19) pandemic renews attention toward nucleic acid therapeutics. While nucleic acid therapy using unmodified DNA or RNA is the primary focus in disease treatment, there is growing need to develop nucleic acid‐based small molecules owing to their potential clinical benefits as drugs in terms of cost and scalability. While small molecules targeting protein–protein interactions are known to alter the transcriptional status of a cell, they can result in a transient effect and variation of bio‐efficacy among patients. Small molecules targeting DNA and/or RNA are in demand in the precision medicine approach as they have consistent bioactivity among patients. This review details the progress of sequence‐specific DNA‐binding pyrrole–imidazole polyamides (PIPs) in modulating the transcriptional status of target gene(s) without altering the underlying DNA sequence. Here, the different versions of PIPs are listed, and also, how conjugating them with DNA alkylating agents, epigenetic modulators, and other drugs can improve their clinical utility as targeted transcription therapeutics. Owing to their specificity, functional diversity, and limited toxicity, PIP technology holds enormous promise as frontrunner in small‐molecule‐based nucleic acid drugs to precisely regulate therapeutically important genes on demand and treat intractable diseases.

Development of gene silencer pyrrole-imidazole polyamides targeting GSK3β for treatment of polycystic kidney diseases

The cyclic adenosine monophosphate (cAMP)–response element binding protein (CREB)–glycogen synthase kinase 3β (GSK3β) signaling pathway was reported to be involved in the progression of autosomal dominant polycystic kidney diseases (ADPKD). We designed and synthesized pyrrole-imidazole (PI) polyamides as novel gene-silencers to prevent binding of CREB on the GSK3β gene promoter and examined the effects of the PI polyamides on proliferation and cyst formation of mouse collecting duct M1 cells. The GSK3β PI polyamides significantly inhibited expression of GSK3β mRNA in M1 cells with forskolin. To obtain cells as collecting ducts from ADPKD, the PKD1 gene was knocked down by shRNA. Lower concentrations of forskolin significantly stimulated proliferation of PKD1 knock-down M1 cells, whereas GSK3β PI polyamide significantly inhibited proliferation of PKD1 knock-down M1 cells with forskolin. Stimulation with forskolin for 5 days induced enlargement of cysts from PKD1 knock-down M1 cells. GSK3β PI polyamides significantly suppressed the enlargement of cysts with forskolin stimulation in PKD1 knock-down M1 cells. Thus, the present study showed that transcriptional suppression of the GSK3β gene by PI polyamides targeting the binding of CREB inhibited the proliferation and cyst formation of PKD1 knock-down M1 cells. The GSK3β PI polyamides may potentially be novel medicines for ADPKD.

Twist-related protein 1 induces epithelial-mesenchymal transition and renal fibrosis through the upregulation of complement 3.

We have demonstrated that complement 3 (C3) is upregulated and induces epithelial-mesenchymal transition (EMT) phenomenon and renal fibrosis in unilateral ureteral obstruction (UUO) kidney. We investigated roles of twist-related protein 1 (TWIST1) in EMT phenomenon and renal fibrosis through C3 upregulation in a mouse UUO model with gene silencer pyrrole-imidazole (PI) polyamides targeting TWIST1. We designed and synthesized PI polyamides targeting TWIST1 binding site on mouse pre-pro C3 promoter. Increased expression C3 mRNA with interferon-γ was significantly inhibited with PI polyamide in nephrotubular epithelial cells. Immunofluorescence showed suppression of E-cadherin and enhancement of α-smooth muscle actin (α-SMA) stainings as EMT phenomena in UUO kidney. TWIST1 and C3 expression was significantly increased in UUO kidney versus contralateral unobstructed kidney (CUK). Expression of transforming growth factor-β1 (TGF-β1), α-SMA and renin mRNAs was increased in UUO kidney versus CUK. Systemic administration of TWIST1 PI polyamide significantly suppressed increased C3 expression in UUO kidney versus CUK. PI polyamide administration also suppressed the increased expression of TGF-β1, α-SMA and renin mRNAs and histologically improved renal fibrosis in UUO kidney. These findings indicate that TWIST1 induces EMT phenomenon and renal fibrosis by TGF-β1 upregulation of C3 in mouse UUO model and that TWIST1 PI polyamide may be a novel medicine for renal fibrosis.

Antitumor effects of pyrrole-imidazole polyamide modified with alkylating agent on prostate cancer cells

Androgens and androgen receptor (AR) have a central role in prostate cancer progression by regulating its downstream signaling. Although androgen depletion therapy (ADT) is the primary treatment for most prostate cancers, they acquires resistance to ADT and become castration resistant prostate cancers (CRPC). AR complex formation with multiple transcription factors is important for enhancer activity and transcriptional regulation, which can contribute to cancer progression and resistance to ADT. We previously demonstrated that OCT1 collaborates with AR in prostate cancer, and that a pyrrole-imidazole (PI) polyamide (PIP) targeting OCT1 inhibits cell and castration-resistant tumor growth (Obinata D et al. Oncogene 2016). PIP can bind to DNA non-covalently without a drug delivery system unlike most DNA targeted therapeutics. In the present study, we developed a PIP modified with a DNA alkylating agent, chlorambucil (ChB) (OCT1-PIP-ChB). Then its effect on the growth of prostate cancer LNCaP, 22Rv1, and PC3 cells, pancreatic cancer BxPC3 cells, and colon cancer HCT116 cells, as well as non-cancerous MCF-10A epithelial cells, were analyzed. It was shown that the IC50s of OCT1-PIP-ChB for 22Rv1 and LNCaP were markedly lower compared to other cells, including non-cancerous MCF-10A cells. Comprehensive gene expression analysis of CRPC model 22Rv1 cells treated with IC50 concentrations of OCT1-PIP-ChB revealed that the gene group involved in DNA double-strand break repair was the most enriched among gene sets repressed by OCT1-PIP-ChB treatment. Importantly, in vivo study using 22Rv1 xenografts, we showed that OCT1-PIP-ChB significantly reduced tumor growth compared to the control group without showing obvious adverse effects. Thus, the PIP combined with ChB can exert a significant inhibitory effect on prostate cancer cell proliferation and castration-resistant tumor growth, suggesting a potential role as a therapeutic agent.

A Series of New Pyrrole Alkaloids with ALR2 Inhibitory Activities from the Sponge Stylissa massa.

Twelve new and four known alkaloids including five different structural scaffolds were isolated from the sponge Stylissa massa collected in the South China Sea. Compound 1 is the first identified precursor metabolite of the classic 5/7/5 tricyclic skeleton with unesterified guanidine and carboxyl groups, compounds 2–5 and 13–15 belong to the spongiacidin-type pyrrole imidazole alkaloids (PIAs). Z- and E-configurations of the spongiacidin-type PIAs often appeared concomitantly and were distinguished by the chemical shift analysis of 13C NMR spectra. The structures of all twelve new compounds were determined by NMR, MS, and ECD analysis combined with single-crystal data of compounds 1, 5, and 10. In the aldose reductase (ALR2) inhibitory assay, six 5/7/5 tricyclic compounds (2–5, 13–15) displayed significant activities. Compounds 13 and 14, as the representative members of spongiacidin-PIAs, demonstrated their ALR2-targeted activities in SPR experiments with KD values of 12.5 and 6.9 µM, respectively.

RUNX inhibitor suppresses graft-versus-host disease through targeting RUNX-NFATC2 axis.

Patients with refractory graft‐versus‐host disease (GVHD) have a dismal prognosis. Therefore, novel therapeutic targets are still needed to be identified. Runt‐related transcriptional factor (RUNX) family transcription factors are essential transcription factors that mediate the essential roles in effector T cells. However, whether RUNX targeting can suppress, and GVHD is yet unknown. Here, we showed that RUNX family members have a redundant role in directly transactivating NFATC2 expression in T cells. We also found that our novel RUNX inhibitor, Chb‐M’, which is the inhibitor that switches off the entire RUNX family by alkylating agent–conjugated pyrrole‐imidazole (PI) polyamides, inhibited T‐cell receptor mediated T cell proliferation and allogenic T cell response. These were designed to specifically bind to consensus RUNX‐binding sequences (TGTGGT). Chb‐M’ also suppressed the expression of NFATC2 and pro‐inflammatory cytokine genes in vitro. Using xenogeneic GVHD model, mice injected by Chb‐M’ showed almost no sign of GVHD. Especially, the CD4 T cell was decreased and GVHD‐associated cytokines including tissue necrosis factor‐α and granulocyte‐macrophage colony‐stimulating factor were reduced in the peripheral blood of Chb‐M’ injected mice. Taken together, our data demonstrates that RUNX family transcriptionally upregulates NFATC2 in T cells, and RUNX‐NFATC2 axis can be a novel therapeutic target against GVHD.

Transcriptional Suppression of Diabetic Nephropathy with Novel Gene Silencer Pyrrole-Imidazole Polyamides Preventing USF1 Binding to the TGF-β1 Promoter.

Upstream stimulatory factor 1 (USF1) is a transcription factor that is increased in high-glucose conditions and activates the transforming growth factor (TGF)-β1 promoter. We examined the effects of synthetic pyrrole-imidazole (PI) polyamides in preventing USF1 binding on the TGF-β1 promoter in Wistar rats in which diabetic nephropathy was established by intravenous administration of streptozotocin (STZ). High glucose induced nuclear localization of USF1 in cultured mesangial cells (MCs). In MCs with high glucose, USF1 PI polyamide significantly inhibited increases in promoter activity of TGF-β1 and expression of TGF-β1 mRNA and protein, whereas it significantly decreased the expression of osteopontin and increased that of h-caldesmon mRNA. We also examined the effects of USF1 PI polyamide on diabetic nephropathy. Intraperitoneal injection of USF1 PI polyamide significantly suppressed urinary albumin excretion and decreased serum urea nitrogen in the STZ-diabetic rats. USF1 PI polyamide significantly decreased the glomerular injury score and tubular injury score in the STZ-diabetic rats. It also suppressed the immunostaining of TGF-β1 in the glomerulus and proximal tubules and significantly decreased the expression of TGF-β1 protein from kidney in these rats. These findings indicate that synthetic USF1 PI polyamide could potentially be a practical medicine for diabetic nephropathy.

Application of DNA-Alkylating Pyrrole-Imidazole Polyamides for Cancer Treatment.

Pyrrole-imidazole (PI) polyamides, which target specific DNA sequences, have been studied as a class of DNA minor-groove-binding molecules. To investigate the potential of compounds for cancer treatment, PI polyamides were conjugated with DNA-alkylating agents, such as seco-CBI and chlorambucil. DNA-alkylating PI polyamides have attracted attention because of their sequence-specific alkylating activities, which contribute to reducing the severe side effects of current DNA-damaging drugs. Many of these types of conjugates have been developed as new candidates for anticancer drugs. Herein, we review recent progress into research on DNA-alkylating PI polyamides and their sequence-specific action on targets associated with cancer development.

Pyrrole carboxamide introduction in the total synthesis of pyrrole–imidazole alkaloids

In this review various strategies for the incorporation of the signature pyrrole carboxamide moiety in the total syntheses of pyrrole-imidazole alkaloids (PIA) are discussed. These so-called oroidin alkaloids have a broad range of biological activities and display interesting skeletal diversity and complexity. These alkaloids are sponge-derived secondary metabolites and thus far more than 200 members of the PIA family have been isolated over the past few decades. Methods range from classical amide bond forming processes to non-traditional bond formation including the de novo synthesis of the pyrrole itself.

Sequence-Specific Control of Mitochondrial Gene Transcription Using Programmable Synthetic Gene Switches Called MITO-PIPs.

Mitochondria possess multiple copies of mitochondrial DNA (mtDNA) that encode 37 genes and their transcription and replication get controlled by unique molecular codes different from that in the nuclear DNA. The mtDNA has been gaining increased attention as one of the critical therapeutic targets as mutations in them impair the function of mitochondria and cause mitochondrial diseases like MELAS. In this chapter, we describe artificial control of mitochondrial transcription based on mtDNA sequence information with a new type of compounds termed MITO-PIPs, which encompasses two domains: pyrrole-imidazole polyamide as DNA recognition domain and mitochondrial penetrating peptide as the mitochondria-targeting domain. Because MITO-PIPs are amenable to tunability, they can be expanded as a synthetic strategy to modulate mitochondrial gene(s) on demand.

Single position substitution of hairpin pyrrole-imidazole polyamides imparts distinct DNA-binding profiles across the human genome.

Pyrrole–imidazole (Py–Im) polyamides are synthetic molecules that can be rationally designed to target specific DNA sequences to both disrupt and recruit transcriptional machinery. While in vitro binding has been extensively studied, in vivo effects are often difficult to predict using current models of DNA binding. Determining the impact of genomic architecture and the local chromatin landscape on polyamide-DNA sequence specificity remains an unresolved question that impedes their effective deployment in vivo. In this report we identified polyamide–DNA interaction sites across the entire genome, by covalently crosslinking and capturing these events in the nuclei of human LNCaP cells. This technique confirms the ability of two eight ring hairpin-polyamides, with similar architectures but differing at a single ring position (Py to Im), to retain in vitro specificities and display distinct genome-wide binding profiles.

Suppression of malignant rhabdoid tumors through Chb-M'-mediated RUNX1 inhibition.

Malignant rhabdoid tumor (MRT) is a rare and highly aggressive pediatric malignancy primarily affecting infants and young children. Intensive multimodal therapies currently given to MRT patients are not sufficiently potent to control this highly malignant tumor. Therefore, additive or alternative therapy for these patients with a poor prognosis is necessary. We herein demonstrated that the inhibition of runt-related transcription factor 1 (RUNX1) by novel alkylating conjugated pyrrole-imidazole (PI) polyamides, which specifically recognize and bind to RUNX-binding DNA sequences, was highly effective in the treatment of rhabdoid tumor cell lines in vitro as well as in an in vivo mouse model. Therefore, suppression of RUNX1 activity may be a novel strategy for MRT therapy.

RUNX-NFAT Axis As a Novel Therapeutic Target for AML and T Cell Immunity

Runt-related transcription factor (RUNX) transcription factors are essential regulators of diverse developmental processes. In mammals, there are three RUNX genes, RUNX1, RUNX2, and RUNX3. All RUNX proteins contain a highly conserved DNA-binding domain, called the runt-homology domain (RHD), which is responsible for DNA-binding and interaction with a partner, core binding factor subunit β (CBFβ). They regulate transcription of target genes, involving hematopoietic differentiation, cell cycle regulation, p53 pathways, and so on. From our previous studies, we assume that compensation mechanism is present among the RUNX family members. RUNX plays pivotal roles in leukemogenesis and inhibition of RUNX has now been widely recognized as a novel strategy in anti-leukemic therapies. However, common mechanism via RUNX in diverse acute myeloid leukemia (AML) remains elusive. Here, we demonstrate that targeting RUNX-nuclear factor of activated T cells 2 (NFATC2) axis is an effective strategy to suppress drug-resistant (DR)-acute promyelocytic leukemia (APL) cells. Silencing of RUNX and NFATC2 in DR-APL cells suppressed cell growth and induced apoptotic cell death. Next, by RNA-seq analysis of several AML patient cohorts, we confirmed that a strong positive correlation between RUNX family (RUNX1,2,3: Pan RUNX) and NFAT family (NFATC1,2,3,4, NFAT5: Pan NFAT) exists not only in APL but also in all hematopoietic malignancies and that AML forms the Pan RUNX high-Pan NFAT high expression cluster. Inspection of the NFATC1-3 promoter revealed the RUNX binding sequence, and direct transcriptionally regulation of NFATC1-3 by RUNX family was confirmed in both chromatin immunoprecipitation (ChIP)-seq analysis and dual luciferase reporter assay. We believe that RUNX-NFAT axis could be an important target in diverse AML. Next, considering the well-established role of RUNX and NFATC2 in T cell immunity, we also apply targeting RUNX-NFATC2 strategy to suppress T cell activation and xenogeneic graft-versus-host disease (GVHD).The expansion of donor T cells requires IL-2, and aGVHD has been defined as a Th1-mediated disease. It is now well known that RUNX, especially RUNX1 and RUNX3 , are highly expressed in T cells, and directly regulate Th1 cytokine genes. As immunosuppressive approach for the prevention or treatment of aGVHD, calcineurin inhibitors, cyclosporine A and tacrolimus, inhibit GVHD by preventing the activation of NFAT, and steroid inhibits transcription of proinflammatory genes. We suppose that targeting RUNX can downregulate NFAT and also cytokine genes in T cell. RUNX1 knockdown and PanRUNX knockdown led to deceased NFATC2 and cytokine gene expression in cytokine-producing Jurkat cell line. It was also confirmed that by inhibiting the RUNX family and suppressing the NFATC2 family at the transcriptional level, the amount of the total NFATC family was significantly reduced compared with the drug that suppresses the nuclear translocation of NFATc2.The importance of RUNX-NFATC2 axis in T cell immunity was also exactly confirmed by the rescue experiments. Finally, to achieve "cluster regulation of RUNX (CROX)" strategy, we have been developing a novel RUNX inhibitor: chlorambucil-conjugated pyrrole-imidazole (PI) polyamides (Chb-M') that targets consensus RUNX-binding sequences, and specifically inhibits binding of RUNX family members. So, Chb-M' can switch off the RUNX target genes efficiently. In diverse AML including APL, core binding factor (CBF)-AML, mixed lineage leukemia (MLL)-rearranged AML, and AML-M0 and so on, Chb-M' was remarkably effective, and suppressed the expression of NFAT family in the protein level and induced apoptotic cell death. ChbM' also had a prominent effect in the AMLPDX model.The importance of RUNX-NFAT axis in AML was confirmed by the pharmacological rescue experiments using phorbol 12-myristate 13-acetate (PMA) and Ionomycin stimulation. Chb-M' also suppressed NFATC2 and cytokine gene expression in peripheral blood mononuclear cells (PBMC) and ameliorated GVHD for xenogeneic GVHD mouse model by transplanting human PBMC into immunodeficient mice. Taken together, we show RUNX could be a novel therapeutic target against diverse AML and GVHD through targeting RUNX-NFAT axis. Disclosures No relevant conflicts of interest to declare.

DNA Alkylation of the RUNX-Binding Sequence by CBI-PI Polyamide Conjugates*.

Many types of molecular targeted drugs that inhibit cancer growth by acting on specific molecules have been developed. The runt-related transcription factor (RUNX) family, which induces cancer development by binding to a specific DNA sequence, has attracted attention as a new target for cancer treatment. We have developed Chb-M', which targets the RUNX-binding sequence. Chb-M' was developed by conjugating pyrrole-imidazole (PI) polyamides and chlorambucil as an anticancer agent. It was recently reported that Chb-M' had a remarkable anticancer effect in vivo. In this study, to explore the possibility of an alternative structure, we designed a new series of CBI-PI polyamides, in which seco-CBI was applied as a DNA-alkylating agent. We examined the characteristics of the CBI-PI polyamides targeting the RUNX-binding sequence and found that these conjugates have great potential for cancer treatment.

A Near-Infrared Fluorogenic Pyrrole-Imidazole Polyamide Probe for Live-Cell Imaging of Telomeres.

Telomeres are closely associated with cellular senescence and cancer. Although some techniques have been developed to label telomeres in living cells for study of telomere dynamics, few biocompatible near-infrared probes based on synthetic molecules have been reported. In this study, we developed a near-infrared fluorogenic pyrrole-imidazole polyamide probe (SiR-TTet59B) to visualize telomeres by conjugating a silicon-rhodamine (SiR) fluorophore with a tandem tetramer pyrrole-imidazole polyamide targeting 24 bp in the telomeric double-stranded (ds) DNA. SiR-TTet59B was almost nonfluorescent in water but increased its fluorescence dramatically on binding to telomeric dsDNA. Using a peptide-based delivery reagent, we demonstrated the specific and effective visualization of telomeres in living U2OS cells. Moreover, SiR-TTet59B could be used to observe the dynamic movements of telomeres during interphase and mitosis. This simple imaging method using a synthetic near-infrared probe could be a powerful tool for studies of telomeres and for diagnosis.

Abstract 2937: The regulation of FGFR signaling by RTK adaptor protein down-regulation through CROX (cluster regulation of RUNX) theory in DNPC

Abstract Up-regulation of the FGFR signaling is frequently-encountered in DNPC: AR-, NE- prostatic cancer and contributes to the maintenance of these cancer cells. Even though, the importance of active FGFR signaling was recognized as a biomarker in DNPC, still core oncogenic driver of DNPC remained unknown. We formerly reported the importance of Pan RUNX (RUNX1,2,3) as an oncogenic driver. Here, we added a new evaluation factors to the examination of CRPC patient cohort to categorize potentially existing DNPC clearly. Pan RUNX was up-regulated in DNPC patients. The inhibition of Pan RUNX reduced the proliferation of DNPC cells significantly, suggesting that Pan RUNX is functionally and critically involved in the cell proliferation mechanism of DNPC. The inhibition of Pan RUNX inhibited FGFR signaling dramatically. On the other hand, the inhibition of FGFR decreased the transactivation of Pan RUNX. To resolve this contradiction, we identified candidate genes which are mediating the crosstalk between FGFR signaling and Pan RUNX. In addition to our formerly reported S100A16, we isolated and examined the adaptor protein family responsible for RTK activation, which are transcriptionally regulated by the RUNX family. In addition, from the analysis by using the CRPC patient cohorts, Pan RUNX expression and SOS1 etc. genes levels were significantly higher in DNPC rather than those of the other subtypes. RUNX family regulates the FGFR signaling pathway in DNPC cells through transactivating expression, rendering itself an ideal target in anti-tumor strategy toward this cancer. Mechanistically, ChIP-qPCR assay and luciferase reporter experiments further validated RUNX family interacts with the RUNX binding DNA sequence located in the candidate genes promoter and positively regulates it. Knockdown of Pan RUNX led to the decreased expression of the adaptor genes as well as dephosphorylation of FGFR, subsequently suppressed the proliferation of DNPC cells. These data suggest that RUNX depletion-mediated growth inhibitory effect on DNPC cells depends on FGFR signal inactivation via transcriptional regulation of adaptor protein. To achieve cluster regulations of RUNX(CROX), We screened our library and isolated our original Pan RUNX inhibitor based on gene switch technology; Chlorambucil-conjugated Pyrrole Imidazole Polyamide (Chb-M'), which specifically binds to the common RUNX binding consensus sequence(TGTGGT) and inhibits RUNX target genes including the adaptor protein, consistently led to the deactivation of the FGFR signaling pathway and was effective against DNPC cell lines and was exceptionally well-tolerated in mice and exerted excellent efficacy against xenograft mice models of DNPC. Taken together, our work identified a novel interaction of RUNX family and the FGFR signaling pathway in DNPC, which can potentially be exploited in the management of this malignancy. Citation Format: Asami Sasaski, Youhei Yanagida, Hiroshi Sugiyama, Souichi Adachhi, Yasuhiko Kamikubo. The regulation of FGFR signaling by RTK adaptor protein down-regulation through CROX (cluster regulation of RUNX) theory in DNPC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2937.