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Introduction: Targeted liposomes using ligand peptides have been applied to deliver therapeutic agents to the target sites. The postinsertion method is commonly used because targeted liposomes can be prepared by simple mixing of ligand peptide-lipid and liposomes. A large-scale preparation method is required for the clinical application of ligand-peptide-modified liposomes. Largescale preparation involves an increase in volume and a change in the preparation conditions. Therefore, the physicochemical properties of liposomes may change owing to large alterations in the preparation conditions. To address this issue, we focused on a microfluidic device and developed a novel ligand peptide modification method, the microfluidic post-insertion method. Methods: We used integrin αvβ3-targeted GRGDS (RGD) and cyclic RGDfK (cRGD)-modified high functionality and quality (HFQ) lipids, which we had previously developed. First, the preparation conditions of the total flow rate in the microfluidic device for modifying HFQ lipids to polyethylene glycol (PEG)-modified (PEGylated) liposomes were optimized by evaluating the physicochemical properties of the liposomes. The targeting ability of integrin αvβ3-expressing colon 26 murine colorectal carcinoma cells was evaluated by comparing the cellular association properties of the liposomes prepared by the conventional post-insertion method. Results: When the RGD-HFQ lipid was modified into PEGylated liposomes by varying the total flow rate (1, 6, and 12 mL/min) of the microfluidic device, as the total flow rate increased, the polydispersity index also increased, whereas the particle size did not change. Furthermore, the RGD- and cRGD-modified PEGylated liposomes prepared at a total flow rate of 1 mL/min showed high cellular association properties equivalent to those prepared by the conventional post-insertion method. Conclusion: Microfluidic post-insertion method of HFQ lipids might be useful for clinical application and large-scale preparation of targeted liposomes., International journal of nanomedicine, 17, pp. 6675-6686; 2022

Several psoralen-conjugated oligonucleotides (Ps-Oligos) have been developed as photo-crosslinkable oligonucleotides targeting DNA or RNA. To avoid potential off-target effects, it is important to investigate the selective photo-crosslinking reactivity of Ps-Oligos to DNA or RNA. However, the selectivity of these Ps-Oligos has not been reported in detail thus far. In this study, we evaluated the photo-crosslinking properties of two Ps-Oligos, 5′-Ps-Oligo and a novel Ps-Oligo containing 2′-O-{[(4,5′,8-trimethylpsoralen)-4′-ylmethoxy]ethylaminocarbonyl}adenosine (APs2-Oligo). Notably, 5′-Ps-Oligo preferentially crosslinked with DNA, whereas APs2-Oligo preferentially crosslinked with RNA. These results demonstrate the interesting crosslinking properties of Ps-Oligos, which will provide useful information for the molecular design of novel Ps-Oligos in future studies., Chemical & pharmaceutical bulletin, 70(10), pp. 726-730

In the process of cell development and differentiation, C-5-methylation of cytosine (5-methylcytosine: 5-mC) in genome DNA is an important transcriptional regulator that switches between differentiated and undifferentiated states. Further, abnormal DNA methylations are often present in tumor suppressor genes and are associated with many diseases. Therefore, 5-mC detection technology is an important tool in the most exciting fields of molecular biology and diagnosing diseases such as cancers. In this study, we found a novel photo-crosslinking property of psoralen-conjugated oligonucleotide (Ps-Oligo) to the double-stranded DNA (ds-DNA) containing 5-mC in the presence of a cationic comb-type copolymer, poly(allylamine)

Off-target interactions between antisense oligonucleotides (ASOs) with state-of-the-art modifications and biological components still pose clinical safety liabilities. To prevent both hybridization-dependent and -independent off-target interactions, a novel nanoarchitecture called BRace On a THERapeutic aSo (BROTHERS or BRO) consisting of typical gapmer ASO and partially complementary peptide nucleic acid (PNA) strand was devised. This non-canonical ASO/PNA hybrids have been shown to have non-specific protein-binding repellent characteristics. Feasible optimization of the structural and thermodynamic characteristics of this duplex system was also demonstrated to elicit in vivo operative toehold-mediated strand displacement (TMSD) reaction, which can reduce hybridization to RNA off-targets. The optimized BROs dramatically mitigated hepatotoxicity while maintaining the on-target knockdown activity of their parent ASOs in vivo. This new technique will not only bring a novel BRO class of drugs that would have a transformative impact on the extrahepatic delivery of ASOs, but also help uncover the toxicity mechanism of ASOs.

Ligand-targeted drug delivery (LTDD) has gained more attention in the field of nucleic acid therapeutics. To further elicit the potential of therapeutic oligonucleotides by means of LTDD, we newly developed (R)- and (S)-3-amino-1,2-propanediol (APD) manifold for ligand conjugation. N-acetylgalactosamine (GalNAc)/asialoglycoprotein receptor (ASGPr) system has been shown to be a powerful and robust paradigm of LTDD. Our novel APD-based GalNAc (GalNAcAPD) was shown to have intrinsic chemical instability that could play a role in better manipulation of active drug release. The APD manifold also enables facile production of conjugates through an on-support ligand cluster synthesis. We showed in a series of in vivo studies that while the knockdown activity of antisense oligonucleotides (ASOs) bearing 5'-GalNAcAPD was comparable to the conventional hydroxy-L-prolinol-linked GalNAc (GalNAcHP), 3'-GalNAcAPD elicited ASO activity by more than twice as much as the conventional 3'-GalNAcHP. This was ascribed partly to the GalNAcAPD's ideal susceptibility to nucleolytic digestion, which is expected to facilitate cytosolic internalization of ASO drugs. Moreover, an in vivo/ex vivo imaging study visualized the enhancement effect of monoantennary GalNAcAPD on liver localization of ASOs. This versatile manifold with chemical and biological instability would benefit therapeutic oligonucleotides that target both the liver and extrahepatic tissues.

Antisense oligonucleotides (ASOs) containing bridged nucleic acids (BNAs) have been proven to be very powerful. However, ensuring a reliable discovery and translational development scheme for this class of ASOs with wider therapeutic windows remains a fundamental challenge. We here demonstrate the robustness of our scheme in the context of the selection of ASOs having two different BNA chemistries (2,′4′-BNA/locked nucleic acid [LNA] and amido-bridged nucleic acid [AmNA]) targeting human proprotein convertase subtilisin/kexin type 9 (PCSK9). The scheme features a two-step process, including (1) a unique and sensitive in vitro screening approach, called Ca2+ enrichment of medium (CEM) transfection, and (2) a ligand-targeted drug delivery approach to better reach target tissues, averting unintended accumulation of ASOs. Using CEM screening, we identified a candidate ASO that shows >70% cholesterol-lowering action in monkeys. An N-acetylgalactosamine (GalNAc) ligand then was appended to the candidate ASO to further broaden the therapeutic margin by altering the molecule’s pharmacokinetics. The GalNAc conjugate, HsPCSK9-1811-LNA, was found to be at least ten times more potent in non-human primates (compared with the unconjugated counterpart), with reduced nephrotoxicity in rats. Overall, we successfully showed that our drug development scheme is better suited for selecting clinically relevant BNA-based ASOs, especially for the treatment of liver-associated diseases., Graphical abstract, A robust discovery and translational development scheme for selection of clinically relevant BNA-based gapmer ASOs was developed. The scheme features a two-step process, including (1) a unique and sensitive in vitro screening approach called CEM and (2) a ligand-targeted drug delivery approach to better reach target tissues, averting unintended side effects.

A facile and reliable fluorescence method for the quantification of urinary uracil concentration is pro-posed herein. The assay utilizes a specific fluorescence (FL) derivatization reaction for uracil using 3-methyl-benzamidoxime as a fluorogenic reagent. Although the presence of urine inhibited the FL reaction, 10 μL of urine was sufficient for the detection of urinary uracil. The uracil derivative was successfully separated from other fluorescent impurities using simple reversed-phase LC with FL detection. Urinary uracil concentra-tions from 16 people were compared with the concentrations obtained by the traditional column-switching liquid chromatographic analysis with UV detection. The FL derivative of uracil appeared as a single peak in the chromatograms of all samples. However, several samples showed an additional peak overlapping the ura-cil peak when using the column-switching method because of UV-active impurities. These results indicated that that the present method is not affected by interfering substances in urine and affords a precise determi-nation of urinary uracil. We expect the proposed method to be applicable for diagnosing dihydropyrimidine dehydrogenase deficiency in 5-fluorouracil chemotherapy., Chemical and Pharmaceutical Bulletin, 69(8), pp. 768-772; 2021

Recently, mRNAs and microRNAs (miRNAs) have been identified in exosomes, which can be taken up by neighboring or distant cells. These exosomal-miRNAs may regulate gene expression in recipient cells. miRNAs are a type of non-coding RNA that induce post-transcriptional gene silencing of their target genes and regulate a wide range of biological processes, including apoptosis, differentiation, metabolism, and cell proliferation. According to recent reports, aberrant expression of miRNAs is associated with most pathological disease processes, including carcinogenesis. Therefore circulating onco-miRs are considered as significant therapeutic targets for cancer therapy. However, there is no report to regulate the function of miRNAs in exosomes. In this study, we developed novel drug delivery system using anti-exosome antibody-oligonucleotide conjugates (ExomiR-Tracker) for functional inhibition of circulating miRNAs. The "ExomiR-Tracker" is the world's first innovative molecule that has targeting property for exosome-recipient cells and specifically delivers nucleic acid medicines to the target cells. We found that ExomiR-Tracker can bind to the surface of exosomes and that the complexes are introduced into exosome-recipient cells then inhibit the activity of miRNA. We showed that ExomiR-Tracker can accumulate in cancerous tumors after intravenous administration. Existing technologies have difficulties for introducing anti-miR into exosomes and extremely low possibility to deliver anti-miR to exosome-recipient cells after intravenous administration. However, we successfully developed useful inhibition technology against exosomal-miRNA.

Point mutations are well characterized activators of oncogenes but are often indistinguishable using common gene technologies. In general, the precise sites of point-mutated oncogenes are difficult...

The asialoglycoprotein receptor (ASGPr) and N-acetylgalactosamine (GalNAc) is one of the most reliable receptor-ligand combinations for delivering antisense oligonucleotides (ASOs) to the liver. Here, we show that a modular GalNAc conjugation strategy allows us to reinforce the activity of the parent, naked 2',4'-BNA/LNA gapmer targeting apolipoprotein B. The conjugation partly reduced a possible hepatotoxicity of the parent ASO. The structure-activity study revealed the significance of the metabolic susceptibility of the GalNAc moiety to nucleolytic cleavage that results in exposure of the parent gapmer. The broad usefulness of our delivery strategy of ASOs to the liver has been demonstrated.

Simple Summary In recent years, nucleic acid drugs, such as antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs), have attracted attention as a new modality for cancer treatment. In this review, we introduce and discuss an overview of various drug delivery systems (DDSs) and ligand modification technologies that are being employed to improve the success and development of these drugs. It is our belief this review will increase the awareness of nucleic acid drugs worldwide and build momentum for the future development of new cancer-targeted versions of these drugs. Abstract With the development of new anticancer medicines, novel modalities are being explored for cancer treatment. For many years, conventional modalities, such as small chemical drugs and antibody drugs, have worked by “inhibiting the function” of target proteins. In recent years, however, nucleic acid drugs, such as ASOs and siRNAs, have attracted attention as a new modality for cancer treatment because nucleic acid drugs can directly promote the “loss of function” of target genes. Recently, nucleic acid drugs for use in cancer therapy have been extensively developed and some of them have currently been under investigation in clinical trials. To develop novel nucleic acid drugs for cancer treatment, it is imperative that cancer researchers, including ourselves, cover and understand those latest findings. In this review, we introduce and provide an overview of various DDSs and ligand modification technologies that are being employed to improve the success and development of nucleic acid drugs, then we also discuss the future of nucleic acid drug developments for cancer therapy. It is our belief this review will increase the awareness of nucleic acid drugs worldwide and build momentum for the future development of new cancer-targeted versions of these drugs.

The 332-nucleotide small nuclear RNA (snRNA) 7SK is a highly conserved non-coding RNA that regulates transcriptional elongation. By binding with positive transcriptional elongation factor b (P-TEFb) via HEXIM1, 7SK snRNA decreases the kinase activity of P-TEFb and inhibits transcriptional elongation. Additionally, it is reported that 7SK inhibition results in the stimulation of human immunodeficiency virus (HIV)-specific transcription. These reports suggest that 7SK is a naturally occurring functional molecule as negative regulator of P-TEFb and HIV transcription. In this study, we developed functional oligonucleotides that mimic the function of 7SK (7SK mimics) as novel inhibitors of HIV replication. We defined the essential region of 7SK regarding its suppressive effects on transcriptional downregulation using an antisense strategy. Based on the results, we designed 7SK mimics containing the defined region. The inhibitory effects of 7SK mimics on HIV-1 long terminal repeat promoter specific transcription was drastic compared with those of the control mimic molecule. Notably, these effects were found to be more enhanced by co-transfection with Tat-expressing plasmids. From these results, it is indicated that 7SK mimics may have great therapeutic potential for HIV/AIDS treatment.

Nucleic acid and genetic medicines are increasingly being developed, owing to their potential to treat a variety of intractable diseases. A comprehensive understanding of the in vivo fate of these agents is vital for the rational design, discovery, and fast and straightforward development of the drugs. In case of intravascular administration of nucleic acids and genetic medicines, interaction with blood components, especially plasma proteins, is unavoidable. However, on the flip side, such interaction can be utilized wisely to manipulate the pharmacokinetics of the agents. In other words, plasma protein binding can help in suppressing the elimination of nucleic acids from the blood stream and deliver naked oligonucleotides and gene carriers into target cells. To control the distribution of these agents in the body, the ligand conjugation method is widely applied. It is also important to understand intracellular localization. In this context, endocytosis pathway, endosomal escape, and nuclear transport should be considered and discussed. Encapsulated nucleic acids and genes must be dissociated from the carriers to exert their activity. In this review, we summarize the in vivo fate of nucleic acid and gene medicines and provide guidelines for the rational design of drugs., Pharmaceutics, 13(2), art. no. 159; 2021

Intracellular delivery is crucial not only in achieving effective oligonucleotide therapeutics but also for a wide variety of therapeutic strategies. In this study to elucidate the effects of the number of incorporated arginine residues on cell membrane permeability, we designed a series of peptide ribonucleic acids (PRNAs) that alternatingly incorporated 4, 8, or 12 arginine residues (PRR1-3) in the PRNA backbone for experimental verifications. Indeed, the cellular uptake efficiency and the aggregation properties turned out to be critical functions of the number of incorporated arginine residues. Thus, the optimized PRR2 that incorporates 8 arginines showed the most efficient cellular uptake ability, much higher than that of octaarginine, without accompanying cytotoxicity or aggregation.

Genome editing has been expected to widely increase the available treatment options for various diseases and permit pharmaceutical interventions in previously untreatable conditions. The availability of genome-editing tools was dramatically increased by the development of the CRISPR-Cas9 system. However, a number of issues limit the use of the CRISPR-Cas9 system and other gene-editing tools in the clinical treatment of diseases. This review summarized the history and types of gene-editing tools and limitations of their use. In addition, the study addressed several next-generation technologies aiming to overcome the limitations of current gene therapy protocols in an effort to accelerate the clinical development of potential treatment options. This review has provided an extensive foundation of the current state of gene-editing technology and its clinical development. This review also indicate that the study additionally highlighted the need for multidisciplinary approaches to overcome current bottlenecks in the development of genome editing.

Nucleic acid medicines have been developed as new therapeutic agents against various diseases; however, targeted delivery of these reagents into cancer cells, particularly hematologic cancer cells, via systemic administration is limited by the lack of efficient and cell-specific delivery systems. We previously demonstrated that monoclonal antibody (mAb)-oligonucleotide complexes targeting exosomal microRNAs with linear oligo-D-arginine (Arg) linkers were transferred into solid cancer cells and inhibited exosomal miRNA functions. In this study, we developed exosome-capturing anti-CD63 mAb-conjugated small interfering RNAs (siRNAs) with branched Arg linkers and investigated their effects on multiple myeloma (MM) cells. Anti-CD63 mAb-conjugated siRNAs were successfully incorporated into MM cells. The incorporation of exosomes was inhibited by endocytosis inhibitors. We also conducted a functional analysis of anti-CD63 mAb-conjugated siRNAs. Ab-conjugated luciferase+ (luc+) siRNAs significantly decreased the luminescence intensity in OPM-2-luc+ cells. Moreover, treatment with anti-CD63 mAb-conjugated with MYC and CTNNB1 siRNAs decreased the mRNA transcript levels of MYC and CTNNB1 to 52.5% and 55.3%, respectively, in OPM-2 cells. In conclusion, exosome-capturing Ab-conjugated siRNAs with branched Arg linkers can be effectively delivered into MM cells via uptake of exosomes by parental cells. This technology has the potential to lead to a breakthrough in drug delivery systems for hematologic cancers.

We synthesized phosphorothioated 2′-OMe RNAs containing PXA residues at the 5′-end of the strands (PXA-ORNs) for sequence-selective inhibition of gene expression of GFP in HeLa cells stably expressing GFP. The inhibitory efficiency is evaluated by measuring the fluorescent intensity of the expressed GFP. Cell-based assay revealed that under UV irradiation, PXA-ORNs greatly inhibit the gene expression of GFP (by as much as 60%).

DNA sequences capable of forming triplexes induce DNA double-strand breaks that have attracted attention in genome editing technologies (e.g., CRISPR/Cas9 system, TALEN, and ZFN). Therefore, novel functional tools that stabilize triplex DNA structures must be further investigated to spark renewed interest. In this study, we investigated the unique character of cationic comb-type copolymers for the selective stabilization of triplex DNA. The melting temperature (Tm) of triplex DNA increased from 24.5 to 73.0 °C (ΔTm = 48.5 °C) by the addition of poly(allylamine)-graft-dextran (PAA-g-Dex) under physiological conditions (at pH 7.0), while PAA-g-Dex did not stabilize but rather destabilized the DNA duplex. On the other hand, poly(l-lysine)-graft-dextran (PLL-g-Dex) stabilized both the duplex and triplex structures at pH 7.0. Thermodynamic parameters evaluated by isothermal titration calorimetry (ITC) revealed that the binding constant (Ka) for the intermolecular triplex formation in the presence of PAA-g-Dex ...

Point mutations are well characterized activators of oncogenes but are often indistinguishable using common gene technologies. In general, the precise sites of point-mutated oncogenes are difficult to distinguish under physiological conditions primarily because single nucleotide mismatch do not affect the annealing temperatures of DNA probes sufficiently. To address this limitation, we developed photo-responsive oligodeoxyribonucleotides containing 2'

The asialoglycoprotein receptor (ASGPr) and

Ligand-targeted drug delivery (LTDD) has emerged as an attractive option in the field of oligonucleotide drugs following the great success of N-acetylgalactosamine (GalNAc)-conjugated siRNA and antisense oligonucleotides. GalNAc is a well-known ligand of the asialoglycoprotein receptor (ASGPR), and is classified as a C-type lectin associated with the metabolism of desialylated glycoproteins. This article describes the synthesis of a non-nucleosidic monovalent GalNAc phosphoramidite-a useful reagent for facilitating the conjugation of GalNAc epitopes into oligonucleotides using DNA synthesizers-together with some important caveats. The monomeric GalNAc consists of three parts: (1) a GalNAc moiety, (2) a linker moiety, and (3) a trans-4-hydroxyprolinol (tHP) branch point. The GalNAc moiety and the tHP moiety are coupled via a condensation reaction to prepare the monovalent GalNAc phosphoramidite. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1: Synthesis of N-acetylgalactosamine ligand Basic Protocol 2: Preparation of trans-4-hydroxyprolinol building block Basic Protocol 3: Preparation of GalNAc phosphoramidite.

A series of chemiluminescent compounds containing a hydrazide group as a nucleophilic functional group has been synthesized. The syntheses were started from chemiluminescent luminol and isoluminol. The linker moiety was easily introduced onto non-nucleophilic exocyclic amino groups of luminol and isoluminol by gentle heating with cyclic acid anhydrides such as glutaric anhydride. The resulting carboxy group was converted to hydrazide by a simple condensation reaction using carbodiimide. Although majority of the synthesized compounds did not emit strong light, a sufficient chemiluminescence intensity was obtained from luminolamido- C2-hydrazide (L2H) comprising of luminol scaffold with a dimethylene linker. The ability of L2H to form a covalent bond with a macromolecule was further investigated by incubation with oxidized horseradish peroxidase. The analysis on matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) MS revealed that the coupling efficiency of L2H was similar to that of commercially available labelling reagent having a hydrazide group. These results suggested that L2H, the luminol hydrazide containing a dimethylene linker, could be useful for the labelling of macromolecules in the sensitive bioassay such as chemiluminescence immunoassay., Chemical and Pharmaceutical Bulletin, 67(8), pp.772-774; 2019

MicroRNAs in exosomes (exosomal miRNAs) are considered as significant targets for cancer therapy. Anti-miR oligonucleotides are often used for the functional inhibition of miRNAs, however, there are no studies regarding the regulation of exosomal miRNA functions. In this study, we attempted to develop a novel drug delivery system using anti-exosome antibody&ndash, anti-miR oligonucleotide complexes (ExomiR-Tracker) to hijack exosomes to carry anti-miR oligonucleotides inside exosome-recipient cells. We found that ExomiR-Tracker bound to the exosomes, and then the complexes were introduced into the recipient cells. We also found that anti-miR oligonucleotides introduced into the recipient cells can exhibit inhibitory effects on exosomal miRNA functions in vitro and in vivo. We believe that our strategy would be a promising one for targeting exosomal miRNAs.

MicroRNAs (miRNAs) regulate gene expression by forming RNA-induced silencing complexes (RISCs) and have been considered as promising therapeutic targets. MiRNA is an essential component of RISC for the modulation of gene expression. Therefore, the release of miRNA from RISC is considered as an effective method for the inhibition of miRNA functions. In our previous study, we reported that anti-miRNA oligonucleotides (AMOs), which are composed of the 2'-O-methyl (2'-OMe) RNA, could induce the release of miRNA from RISC. However, the mechanisms underlying the miRNA-releasing effects of chemically modified AMOs, which are conventionally used as anti-cancer drugs, are still unclear. In this study, we investigated the relationship between the miRNA releasing rate from RISC and the inhibitory effect on RISC activity (IC50) using conventional chemically modified AMOs. We demonstrated that the miRNA-releasing effects of AMOs are directly proportional to the IC50 values, and AMOs, which have an ability to promote the release of miRNA from RISC, can effectively inhibit RISC activity in living cells.

Nucleic acid medicines including small interfering RNAs (siRNAs) are expected to be next-generation therapies. However, targeted delivery of siRNAs into cancer cells, especially hematological cancer cells, via systemic administration is limited by the lack of efficient and cell-specific delivery systems. We previously demonstrated that cancer cell-derived exosomes are preferentially transfer into their parental cancer cells. Based on this observation, we hypothesized that monoclonal antibody (mAb)-conjugated siRNAs that capture exosomes can efficiently deliver siRNAs into hematological cancer cells (Figure 1). To test this hypothesis, we developed a noncovalent Ab-conjugated siRNA system and confirmed the efficient delivery into multiple myeloma (MM) cells. We selected the surface antigen CD63 to capture MM cell-derived exosomes. An anti-CD63 mAb was thiolated using Traut's reagent and then modified with a linear (D-arginine (Arg))9 (9r) or branched (Arg)18 (9+9r) peptide (vehicle). The anti-CD63 mAb-Arg:siRNA complex was obtained by mixing anti-CD63 mAb-Arg and siRNA in phosphate-buffered saline and incubating the mixture. A gel shift assay showed that the anti-CD63 mAb-linear Arg construct bound to siRNAs in a construct concentration-dependent manner and the optimal vehicle-to-siRNA ratio was 5:1. By contrast, the anti-CD63 mAb-branched Arg construct bound to siRNAs at lower concentrations, and the optimal vehicle-to-siRNA ratio was 1:1-2.5:1. We next examined uptake of fluorescence-labeled siRNAs by OPM-2 MM cells using a confocal microscope. A higher level of siRNAs was delivered using the anti-CD63 mAb-branched Arg construct than using the anti-CD63 mAb-linear Arg construct; therefore, we used the former construct for further experiments. We investigated the knockdown effects of the CD63 mAb-branched Arg construct conjugated with luc siRNA in luciferase-expressing OPM-2 cells (OPM-2-luc cells). Luciferase activity decreased to 55.9% in OPM-2-luc cells following uptake of this construct. We next examined the mRNA transcript levels of MYC and CTNNB1 (β-catenin) mRNA transcript levels by RT-PCR in OPM-2 cells treated with the anti-CD63 mAb-branched Arg construct conjugated with MYC and CTNNB1 siRNAs. Treatment with mAb-conjugated siRNAs at a vehicle-to-siRNA ratio of 1:1 decreased the mRNA transcript levels of MYC and CTNNB1 to 52.5% and 55.3%, respectively (Figure 2). In conclusion, exosome-capturing antibody-conjugated siRNAs are effectively delivered into MM cells via uptake of exosomes by parental cells. We are currently investigating their delivery into other hematological cancer cells. This technology might lead to a breakthrough in drug delivery systems for hematological cancers. Disclosures No relevant conflicts of interest to declare.

We developed a novel method for regulation of RISC function by photoreactive oligonucleotides (Ps-Oligo) containing 2′-O-psoralenylmethoxyethyl adenosine (Aps). We observed that inhibitory effects of Ps-Oligos on RISC function were enhanced by UV-irradiation compared with 2′-O-methyl-oligonucleotide without Aps. These results suggest Ps-Oligo inhibited RISC function by cross-linking effect, and we propose that the concept described in this report may be promising and applicable one to regulate the small RNA-mediated post-transcriptional regulation.

"Triple-negative" (TN) breast cancers, which are characterized by estrogen receptor (-), progesterone receptor (-), and human epidermal growth factor receptor 2 (-), are typically associated with poor prognosis because of their aggressive tumor phenotypes. In recent years, the number of patients with breast cancers has remarkably increased, but there are only few available drugs for treatment of TN breast cancers. The development of novel drugs targeting TN breast cancer is urgently required. In the present study, we focused on the function of special AT-rich sequence binding protein 1 (SATB1) as a target molecule for the treatment of TN breast cancers. By recruiting chromatin remodeling enzymes and transcriptional factors, SATB1 regulates the expression of >1,000 genes related to cell growth and translocation. We synthesized a decoy DNA against SATB1, including the recognition sequence of SATB1. We examined the inhibitory effects of the decoy DNAs on cellular proliferation of a TN metastatic breast cancer cell line (MDA-MB-231). SATB1-decoy DNA inhibited the proliferation of MDA-MB-231 cells. Especially, it was significant that SATB1-decoy DNA drastically reduced the invasive and metastatic capacity of MBA-MB-231 cells. Further, in the case of MCF7 cells (SATB1-negative breast cancer cell line), SATB1-decoy DNA did not exhibit any inhibitory effect. These data suggest that SATB1-decoy DNA may be an effective candidate for use as a molecular-targeting drug for treatment of TN breast cancer.

It has been reported that point mutations in genes are responsible for various cancers, and the selective regulation of gene expression is an important factor in developing new types of anticancer drugs. To develop effective drugs for the regulation of point-mutated genes, we focused on photoreactive antisense oligonucleotides. Previously, we reported that photoreactive oligonucleotides containing 2'-O-psoralenylmethoxyethyl adenosine (2'-Ps-eom) showed drastic photoreactivity in a strictly sequence-specific manner. Here, we demonstrated the specific gene regulatory effects of 2'-Ps-eom on [(12)Val]K-ras mutant (GGT --GTT). Photo-cross-linking between target mRNAs and 2'-Ps-eom was sequence-specific, and the effect was UVA irradiation-dependent. Furthermore, 2'-Ps-eom was able to inhibit K-ras-immortalized cell proliferation (K12V) but not Vco cells that have the wild-type K-ras gene. These results suggest that the 2'-Ps-eom will be a powerful nucleic acid drug to inhibit the expression of disease-causing point mutation genes, and has great therapeutic potential in the treatment of cancer.

2'-O-psoralen-conjugated antisense oligonucleotide was able to recognize a point mutation of mRNA. It had outstanding ability to photo-cross-link only to oligoribonucleotides (ORN) having a point mutation. This type of antisense molecule is the only one of its kind so far. To give high photo-cross-linking efficiency and sequence selectivity to antisense molecules, we synthesized novel photo-reactive oligonucleotides (2'-Ps-xom) containing psoralen at the 2'-O-position adenosine via an ethoxymethylene (2'-Ps-eom), propoxymethylene (2'-Ps-pom) and butoxymethylene (2'-Ps-bom) linker, respectively. We evaluated the photo-cross-linking efficiency and sequence selectivity in photo-cross-linking of 2'-Ps-xom to the complementary ORN and to an ORN having a mismatch base. Among them, 2'-Ps-eom exhibited superior photo-cross-linking efficiency with high sequence selectivity.

Because point mutations in GTPase-coding genes have been reported to be responsible for the transformation of cells, anticancer reagents that react effectively and sequence selectively with target RNAs having a point mutation are highly desired. In this study, we developed novel photo-cross-linking oligodeoxyribonucleotides ((pro)PCA-ODNs) that had a caged α-chloroaldehyde group conjugated to a 2-methylpropanediyl backbone ((pro)PCA) in the middle of the strand. A kinetic study of the deprotection reaction of (pro)PCA-ODN revealed that the bis(2-nitrobenzyl)acetal group was completely deprotected within 1 min. Photo-cross-linking studies of (pro)PCA-ODNs with complementary oligoribonucleotides (ORNs) revealed that (pro)PCA-ODNs reacts efficiently and selectively with the target ORNs that have an adenosine or cytidine residue at a frontal position of the (pro)PCA residue without adverse effects of bases adjacent to the mutation site.

Delivery systems of small interfering RNA (siRNA) are the key to siRNA therapeutic application. In this study, we prepared and evaluated a series of cationic comb-type copolymers (CCCs) possessing a polycationic backbone (less than 30 weight (wt) %) and abundant water-soluble side chains (more than 70 wt.%) as a siRNA carrier with prolonged blood circulation time. Markedly, the CCC with the higher side chain content (10 wt.% PLL and 90 wt.% PEG) showed stronger interaction with siRNA than that with the lower content (30 wt.% PLL and 70 wt.% PEG), suggesting that highly dense PEG brush reinforces interpolyelectrolyte complex between the PLL backbone and siRNA. The siRNA complexed with the CCC was resistant to nucleases in 90% plasma for 24 h in vitro. The CCC having the higher side chain content increased circulation time of siRNA in mouse bloodstream by 100-fold. Surprisingly, even when the CCC and siRNA were separately injected into mouse at 20 min interval, blood circulation of post-injected siRNA was significantly increased. These results imply that the CCC has higher selectivity in its ionic interaction with siRNA than other anionic substances in blood stream. To our knowledge, this is the first example of a polyplex carrier that prolongs blood circulation time of unmodified siRNA without resource-consuming preparation process.

A series of poly(L-lysine)-graft-polyethylene glycol (PLL-g-PEG) was prepared by a reductive amination reaction of PLL with aldehyde modified PEG using NaBH3CN as a reductant. The high coupling efficacy observed in the 80% acetonitrile aqueous solution led to the grafting polymers with abundant PEG chains (more than 90 wt % and 30 mol %). By the method, we can retain high cationic charge density of the polymer backbone, because the resulting secondary amino groups are still protonated. By controlling the primary structure of the copolymer, we can also regulate the ionic interaction with nucleic acids and other biological components for gene delivery purpose.

The unique folding and assembling properties of DNA have been elaborated to construct various nanomachines that can be reversibly switched between two or more distinct conformations. For the better applications and developments of DNA nanomachines, their responding kinetics, outputs, and sequence-selectivity need to be improved. Furthermore, the DNA nanomachines currently have several limitations in the operation conditions such as temperature, salt condition, and DNA strand concentration. In this study, we evaluated the effect of a cationic copolymer on the responses of a DNA-fueled nanomachine. We found that the copolymer increases quickness of the nanomachine under moderate conditions including physiologically relevant conditions even at very low strand concentrations (nM range).

Background It has been proposed that the human endometrium may contain a population of adult stem cells that are responsible for its remarkable regenerative capability. Recently, a subset of stem cells or progenitor cells in adult tissue has been identified as side-population cells (SP cells) displaying low staining with Hoechst 33342 by fluorescence-activated cell sorter (FACS) analysis. In this study, we isolated SP cells from the human endometrium and analysed their properties. Method Endometrial cells were obtained using enzymatic digestion from uterine hysterectomy for the treatment of uterine myoma and stained with Hoechst 33342 dye either alone or in combination with verapamil. The cells were then analysed using FACS. Results SP cells were present among normal human endometrial cells. Most SP cells were enriched in the CD9(-)CD13(-) fraction. These SP cells showed long-term repopulating properties and produced gland (CD9(+))- and stroma (CD13(+))-like cells. CD9(-)CD13(-) cells isolated from the endometrium also generated gland- or stroma-like cells. Conclusions SP cells in the human endometrium can function as progenitor cells. This is the first report of the phenotype of SP cells from normal human endometrial cells.

MicroRNAs (miRNAs) are known to be important post-transcription regulators of gene expression. Aberrant miRNA expression is associated with pathological disease processes, including carcinogenesis. Therefore, miRNAs are considered significant therapeutic targets for cancer therapy. MiRNAs do not act alone, but exhibit their functions by forming RNA-induced silencing complex (RISC). Thus, the regulation of RISC activity is a promising approach for cancer therapy. MiRNA is a core component of RISC and is an essential to RISC for recognizing target mRNA. Thereby, it is expected that development of the method to promote the release of miRNA from RISC would be an effective approach for inhibition of RISC activity. In this study, we synthesized novel peptide-conjugated oligonucleotides (RINDA-as) to promote the release of miRNA from RISC. RINDA-as showed a high rate of miRNA release from RISC and high level of inhibitory effect on RISC activity.