Qki5 safeguards spinal motor neuron function by defining the motor neuron-specific transcriptome via pre-mRNA processing.

Many RNA-binding proteins (RBPs) are linked to the dysregulation of RNA metabolism in motor neuron diseases (MNDs). However, the molecular mechanisms underlying MN vulnerability have yet to be elucidated. Here, we found that such an RBP, Quaking5 (Qki5), contributes to formation of the MN-specific transcriptome profile, termed "MN-ness," through the posttranscriptional network and maintenance of the mature MNs.

Sbp2l contributes to oligodendrocyte maturation through translational control in Tcf7l2 signaling.

Oligodendrocytes (OLs) are the myelin-forming cells in the CNS that support neurons through the insulating sheath of axons. This unique feature and developmental processes are achieved by extrinsic and intrinsic gene expression programs, where RNA-binding proteins can contribute to dynamic and fine-tuned post-transcriptional regulation. Here, we identified SECIS-binding protein 2-like (Sbp2l), which is specifically expressed in OLs by integrated transcriptomics.

DNA damage stress-induced translocation of mutant FUS proteins into cytosolic granules and screening for translocation inhibitors.

Fused in sarcoma/translated in liposarcoma (FUS) is an RNA-binding protein, and its mutations are associated with neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), through the DNA damage stress response, aberrant stress granule (SG) formation, etc. We previously reported that translocation of endogenous FUS into SGs was achieved by cotreatment with a DNA double-strand break inducer and an inhibitor of DNA-PK activity. In the present study, we investigated cytoplasmic SG formation using various fluorescent protein-tagged mutant FUS proteins in a human astrocytoma cell (U251) model.

Potential benefit of the cathepsin S inhibitor, ASP1617, as a treatment for systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the dysregulation of various cell types and immunological pathways. Autoantibodies play an important role in its pathogenesis. The presence of autoantibodies suggests that self-antigen presentation through major histocompatibility complex (MHC) class II on antigen presenting cells is involved in the pathogenesis of autoimmune diseases, including SLE.

Copper-64-Labeled Antibody Fragments for Immuno-PET/Radioimmunotherapy with Low Renal Radioactivity Levels and Amplified Tumor-Kidney Ratios.

Copper-64 (Cu)-labeled antibody fragments such as Fab are useful for molecular imaging (immuno-PET) and radioimmunotherapy. However, these fragments cause high and persistent localization of radioactivity in the kidneys after injection. To solve this problem, this study assessed the applicability of a molecular design to Cu, which reduces renal radioactivity levels by liberating a urinary excretory radiometabolite from antibody fragments at the renal brush border membrane (BBM).

Combined treatment of pancreatic cancer xenograft with Y-ITGA6B4-mediated radioimmunotherapy and PI3K/mTOR inhibitor.

Aim: To investigate the therapeutic effect of combined integrin αβ-targeted radioimmunotherapy (RIT) and PI3K/mTOR inhibitor BEZ235 in a pancreatic cancer model.

Methods: Phosphorylation of Akt, mTOR, the downstream effectors eukaryotic initiation factor 4E binding protein 1 (4EBP1) and S6 ribosomal protein (S6) were evaluated in BxPC-3 human pancreatic cancer cells treated with Yttrium-90 (Y) labeled anti-integrin αβ antibody (ITGA6B4) and BEZ235 by western blotting. The cytotoxic effect of BEZ235 was investigated using a colony formation assay.

Cu-ATSM internal radiotherapy to treat tumors with bevacizumab-induced vascular decrease and hypoxia in human colon carcinoma xenografts.

Bevacizumab, an anti-vascular endothelial growth factor (VEGF) antibody, is an antiangiogenic agent clinically used for various cancers. However, repeated use of this agent leads to tumor-decreased vascularity and hypoxia with activation of an HIF-1 signaling pathway, which results in drug delivery deficiency and induction of malignant behaviors in tumors. Here, we developed a novel strategy to treat tumors with bevacizumab-induced vascular decrease and hypoxia using Cu-diacetyl-bis (-methylthiosemicarbazone) (Cu-ATSM), a potential theranostic agent, which possesses high tissue permeability and can target over-reduced conditions under hypoxia in tumors, with a human colon carcinoma HT-29 tumor-bearing mouse model.

An RNA-binding protein, Qki5, regulates embryonic neural stem cells through pre-mRNA processing in cell adhesion signaling.

Cell type-specific transcriptomes are enabled by the action of multiple regulators, which are frequently expressed within restricted tissue regions. In the present study, we identify one such regulator, Quaking 5 (Qki5), as an RNA-binding protein (RNABP) that is expressed in early embryonic neural stem cells and subsequently down-regulated during neurogenesis. mRNA sequencing analysis in neural stem cell culture indicates that Qki proteins play supporting roles in the neural stem cell transcriptome and various forms of mRNA processing that may result from regionally restricted expression and subcellular localization.

67Cu-Radiolabeling of a multimeric RGD peptide for αVβ3 integrin-targeted radionuclide therapy: stability, therapeutic efficacy, and safety studies in mice.

Objective: Copper-67 (Cu) is one of the most promising radionuclides for internal radiation therapy. Globally, several projects have recently been initiated for developing innovative approaches for the large-scale production of Cu. Encouraged by these, we performed Cu-radiolabeling of a tetrameric cyclic Arg-Gly-Asp (cRGD) peptide conjugate, cyclam-RAFT-c(-RGDfK-)4, which selectively targets αVβ3 integrin (αVβ3), the transmembrane receptor involved in tumor invasion, angiogenesis, and metastasis.

Positron emission tomography of cerebral angiogenesis and TSPO expression in a mouse model of chronic hypoxia.

The present study aimed to examine whether positron emission tomography (PET) could evaluate cerebral angiogenesis. Mice were housed in a hypoxic chamber with 8-9% oxygen for 4, 7, and 14 days, and the angiogenic responses were evaluated with a radiotracer, Cu-cyclam-RAFT-c(-RGDfK-), which targeted αβ integrin and was imaged with PET. The PET imaging results showed little uptake during all of the hypoxic periods.

Radioimmunotherapy of pancreatic cancer xenografts in nude mice using 90Y-labeled anti-α6β4 integrin antibody.

The contribution of integrin α6β4 (α6β4) overexpression to the pancreatic cancer invasion and metastasis has been previously shown. We have reported immunotargeting of α6β4 for radionuclide-based and near-infrared fluorescence imaging in a pancreatic cancer model. In this study, we prepared yttrium-90 labeled anti-α6β4 antibody (90Y-ITGA6B4) and evaluated its radioimmunotherapeutic efficacy against pancreatic cancer xenografts in nude mice.

αVβ3 Integrin-Targeted Radionuclide Therapy with 64Cu-cyclam-RAFT-c(-RGDfK-)4.

The transmembrane cell adhesion receptor αVβ3 integrin (αVβ3) has been identified as an important molecular target for cancer imaging and therapy. We have developed a tetrameric cyclic RGD (Arg-Gly-Asp) peptide-based radiotracer (64)Cu-cyclam-RAFT-c(-RGDfK-)4, which successfully captured αVβ3-positive tumors and angiogenesis by PET. Here, we subsequently evaluated its therapeutic potential and side effects using an established αVβ3-positive tumor mouse model.

Immunotargeting of Integrin α6β4 for Single-Photon Emission Computed Tomography and Near-Infrared Fluorescence Imaging in a Pancreatic Cancer Model.

To explore suitable imaging probes for early and specific detection of pancreatic cancer, we demonstrated that α6β4integrin is a good target and employed single-photon emission computed tomography (SPECT) or near-infrared (NIR) imaging for immunotargeting. Expression levels of α6β4were examined by Western blotting and flow cytometry in certain human pancreatic cancer cell lines. The human cell line BxPC-3 was used for α6β4-positive and a mouse cell line, A4, was used for negative counterpart.

(64)Cu-ATSM therapy targets regions with activated DNA repair and enrichment of CD133(+) cells in an HT-29 tumor model: Sensitization with a nucleic acid antimetabolite.

(64)Cu-diacetyl-bis (N(4)-methylthiosemicarbazone) ((64)Cu-ATSM) is a potential theranostic agent targeting the over-reduced state under hypoxia within tumors. Recent clinical Cu-ATSM positron emission tomography studies have revealed a correlation between uptake and poor prognosis; however, the reason is unclear. Here, using a human colon carcinoma HT-29 model, we demonstrated that the intratumoral (64)Cu-ATSM high-uptake regions exhibited malignant characteristics, such as upregulated DNA repair and elevated %CD133(+) cancer stem-like cells.

Regorafenib as a potential adjuvant chemotherapy agent in disseminated small colon cancer: Drug selection outcome of a novel screening system using nanoimprinting 3-dimensional culture with HCT116-RFP cells.

Colon cancer is one of the leading causes of cancer death worldwide. Adjuvant chemotherapy following primary surgical treatment is suggested to be beneficial in eradicating invisible disseminated small tumors in colon cancer; however, an effective drug remains to be developed. Recently, we reported a novel drug screening system using a nanoimprinting 3-dimensional (3D) culture that creates multicellular spheroids, which simulate in vivo conditions and, thereby, predict effective drugs in vivo.

Immuno-PET Imaging of HER3 in a Model in which HER3 Signaling Plays a Critical Role.

HER3 is overexpressed in various carcinomas including colorectal cancer (CRC), which is associated with poor prognosis, and is involved in the development of therapy resistance. Thus, an in vivo imaging technique is needed to evaluate the expression of HER3, an important therapeutic and diagnostic target. Here, we report successful HER3 PET imaging using a newly generated anti-human HER3 monoclonal antibody, Mab#58, and a mouse model of a HER3-overexpressing xenograft tumor.

Transcriptomic Signatures of Auger Electron Radioimmunotherapy Using Nuclear Targeting (111)In-Trastuzumab for Potential Combination Therapies.

(111)In-labeled trastuzumab modified with nuclear localizing signal (NLS) peptides ((111)In-trastuzumab-NLS) efficiently delivers an Auger electron (AE) emitter (111)In into the cell nucleus and is thus a promising radiopharmaceutical in AE radioimmunotherapy (AE-RIT) for targeted killing of HER2-positive cancer. However, further improvement of its therapeutic efficacy is required. In this study, the authors show a transcriptomic approach to identify potential targets for enhancing the cytotoxic effects of (111)In-trastuzumab-NLS.

Development of the Fibronectin-Mimetic Peptide KSSPHSRN(SG)5RGDSP as a Novel Radioprobe for Molecular Imaging of the Cancer Biomarker α5β1 Integrin.

α5β1 Integrin, a fibronectin receptor, is becoming a pertinent therapeutic target and a promising prognostic biomarker for cancer patients. The aim of this study was to functionalize an α5β1-specific fibronectin-mimetic peptide sequence KSSPHSRN(SG)5RGDSP (called PR_b) as a positron emission tomography (PET) probe. PR_b was modified by addition of a β-alanine residue, conjugated with 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA), and radiolabeled with (18)F based on the chelation of (18)F-aluminum fluoride.

Validation of 64Cu-ATSM damaging DNA via high-LET Auger electron emission.

Radioactive copper (II) (diacetyl-bis N4-methylthiosemicarbazone) (Cu-ATSM) isotopes were originally developed for the imaging of hypoxia in tumors. Because the decay of a (64)Cu atom is emitting not only positrons but also Auger electrons, this radionuclide has great potential as a theranostic agent. However, the success of (64)Cu-ATSM internal radiation therapy would depend on the contribution of Auger electrons to tumor cell killing.

A limited overlap between intratumoral distribution of 1-(5-fluoro-5-deoxy-α-D-arabinofuranosyl)-2-nitroimidazole and copper-diacetyl-bis[N(4)-methylthiosemicarbazone].

Positron emission tomography (PET) imaging of tumor hypoxia provides valuable information for cancer treatment planning. Two types of PET tracers, nitroimidazole compounds and [62,64Cu] copper-diacetyl-bis[N(4)-methylthio- semicarbazone] (Cu-ATSM), have been used for imaging hypoxic tumors. High accumulation of these tracers in tumors was shown to predict poor prognosis.

High-throughput screening with nanoimprinting 3D culture for efficient drug development by mimicking the tumor environment.

Anti-cancer drug development typically utilizes high-throughput screening with two-dimensional (2D) cell culture. However, 2D culture induces cellular characteristics different from tumors in vivo, resulting in inefficient drug development. Here, we report an innovative high-throughput screening system using nanoimprinting 3D culture to simulate in vivo conditions, thereby facilitating efficient drug development.

Prediction of hepatic and intestinal glucuronidation using in vitro-in vivo extrapolation.

The accurate prediction of hepatic (Fh) and intestinal availability (Fg) is vital for determining human pharmacokinetics. To predict these PK parameters for cytochrome P450 (P450) metabolism, in vitro-in vivo extrapolation (IVIVE) using hepatic microsomes, hepatocytes, and intestinal microsomes has been actively investigated. However, IVIVE has not been sufficiently evaluated for non-P450 enzymes.

Quantifying initial cellular events of mouse radiation lymphomagenesis and its tumor prevention in vivo by positron emission tomography and magnetic resonance imaging.

Radiation-induced thymic lymphoma (RITL) in mice is induced by fractionated whole-body X-irradiation (FX) and has served as a useful model for studying radiation carcinogenesis. In this model, the initial postirradiation cellular events in the thymus and bone marrow (BM) are critically important for tumorigenesis, and BM transplantation (BMT) prevents RITL. However, direct assessment of these events is so far restricted by the lack of noninvasive monitoring techniques.

Mutant phenotype analysis suggests potential roles for C-type natriuretic peptide receptor (NPR-B) in male mouse fertility.

Background: C-type natriuretic peptide (CNP) signaling through its receptor natriuretic peptide receptor B (NPR-B) is a key molecule for mammalian reproduction, and known to play important roles in female fertility. However, the function of these peptides in mouse male reproduction remains largely unknown. To determine the role of CNP/NPR-B signaling in male reproduction we investigated phenotype of Npr2-deficient short-limbed-dwarfism (Npr2(slw/slw)) mice, which have been shown to have gastrointestinal (GI) abnormalities.