Publications by authors named "Mayumi Takano-Kasuya"

7 Publications

  • Page 1 of 1

The anti-angiogenic agent lenvatinib induces tumor vessel normalization and enhances radiosensitivity in hepatocellular tumors.

Med Oncol 2021 Apr 21;38(6):60. Epub 2021 Apr 21.

Department of Medical Physics, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.

The evaluation of angiogenesis inhibitors requires the analysis of the precise structure and function of tumor vessels. The anti-angiogenic agents lenvatinib and sorafenib are multi-target tyrosine kinase inhibitors that have been approved for the treatment of hepatocellular carcinoma (HCC). However, the different effects on tumor vasculature between lenvatinib and sorafenib are not well understood. In this study, we analyzed the effects of both drugs on vascular structure and function, including vascular normalization, and investigated whether the normalization had a positive effect on a combination therapy with the drugs and radiation using micro X-ray computed tomography with gold nanoparticles as a contrast agent, as well as immunohistochemical analysis and interstitial fluid pressure (IFP) measurement. In mice subcutaneously transplanted with mouse HCC cells, treatment with lenvatinib or sorafenib for 14 days inhibited tumor growth and reduced the tumor vessel volume density. However, analysis of integrated data on vessel density, rates of pericyte-covering and perfused vessels, tumor hypoxia, and IFP measured 4 days after drug treatment showed that treatment with 3 mg/kg of lenvatinib significantly reduced the microvessel density and normalized tumor vessels compared to treatment with 50 mg/kg of sorafenib. These results showed that lenvatinib induced vascular normalization and improved the intratumoral microenvironment in HCC tumors earlier and more effectively than sorafenib. Moreover, such changes increased the radiosensitivity of tumors and enhanced the effect of lenvatinib and radiation combination therapy, suggesting that this combination therapy is a powerful potential application against HCC.
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http://dx.doi.org/10.1007/s12032-021-01503-zDOI Listing
April 2021

Development of X-ray contrast agents using single nanometer-sized gold nanoparticles and lactoferrin complex and their application in vascular imaging.

Colloids Surf B Biointerfaces 2021 Apr 1;203:111732. Epub 2021 Apr 1.

Department of Medical Physics, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan; International Center for Synchrotron Radiation InnovationSmart (SRIS), Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan. Electronic address:

The technology to accurately image the morphology of tumor vessels with X-ray contrast agents is important to clarify mechanisms underlying tumor progression and evaluate the efficacy of chemotherapy. However, in clinical practice, iodine-based contrast agents present problems such as short blood retention owing to a high clearance ability and insufficient X-ray absorption capacity when compared with other high atomic number elements. To resolve these issues, gold nanoparticles (AuNPs), with a high atomic number, have attracted a great deal of attention as contrast agents for angiography, and have been employed in small animal models. Herein, we developed novel contrast agents using AuNPs and captured changes in tumor vessel morphology with time using X-ray computed tomography (CT). First, glutathione-supported single nanometer-sized AuNPs (sAu/GSH) (diameter, 2.2 nm) were fabricated using tetrakis(hydroxymethyl)phosphonium chloride as a reducing agent. The sAu/GSH particles were intravenously injected into mice, remained in vessels for a few minutes, and were then excreted by the kidneys after 24 h, similar to the commercial contrast agent iopamidol. Next, the Au/GSH and lactoferrin (sAu/GSH-LF) (long axis size, 17.3 nm) complex was produced by adding lactoferrin to the sAu/GSH solution under the influence of a condensing agent. On intravenously administering sAu/GSH-LF to mice, the blood retention time was 1-3 h, which was considerably longer than that observed with iopamidol and sAu/GSH. Moreover, we succeeded in imaging morphological changes in identical tumor vessels for several days using X-ray CT with sAu/GSH-LF.
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http://dx.doi.org/10.1016/j.colsurfb.2021.111732DOI Listing
April 2021

[Supporting Technology for Development of Antibody Drug and Diagnostic Method to Predict Response to the Drug, by Using Fluorescence Imaging].

Gan To Kagaku Ryoho 2021 Feb;48(2):170-175

Dept. of Medical Physics, Graduate School of Medicine, Tohoku University.

Fluorescence imaging is a very useful method for visualizing molecules and cells, but when tissues are measured", decrease in resolution due to increased scattering and absorption of light in proportion to tissue thickness (problem 1)" and "decrease in signal to noise(S/N)ratio of positive signal due to tissue autofluorescence(problem 2)"are problems to be solved. In this paper, to develop a technology to improve the analysis accuracy of drug efficacy mechanisms in preclinical trial of drug discovery, we performed development of a supporting technology for drug discovery of antibody drug conjugates by imaging living tumor tissues, while solving problem 1. This technology is expected to lead to an improvement in the success rate of clinical trials. Next, to develop a diagnostic method to predict the response to neoadjuvant chemotherapy with antibody drugs for breast cancer, we performed development of fluorescence imaging of pathological tissues using fluorescent nanoparticles with ultra-high brightness, while solving problem 2. This diagnostic technology makes it possible to evaluate the expression level of the target protein of antibody drug with high quantitative and wide range sensitivity. This improved the accuracy of drug efficacy prediction. Therefore, patients who are expected to have a low drug efficacy will be able to select anticancer drugs with different mechanisms of action. These results of this study showed the reduction of drug discovery costs and improvement of individualized medicine. Thus, this study will greatly contribute to the development of precision medicine.
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February 2021

PEGylation of Co-Zn Ferrite Nanoparticles for Theranostics.

J Nanosci Nanotechnol 2020 Dec;20(12):7255-7262

Department of Physics, Graduate School of Science and Engineering, Yokohama National University, Yokohama, Kanagawa, 240-8501, Japan.

Multi-element ferrite nanoparticles (NPs) were synthesized as heat agents for use in magnetic hyperthermia treatments, specifically, CoZnFe₂O₄ NPs coating with polyethylene glycol. The crystal structures of these particles were examined by X-ray diffraction. Particle diameters were controlled to be approximately 10 nm by controlling the annealing temperature and time. The modification of polyethylene glycol (PEG) on the particles was confirmed by mass spectrometry and Fourier-transform infrared spectrometry. The heat dissipation characteristics of the particles were investigated by measuring AC magnetic susceptibility and temperature increase in AC magnetic fields. A peak in the imaginary part of AC magnetic susceptibility appeared, depending on the frequency. The value of was found to contribute to the effective heat dissipation according to the Neel relaxation system. The temperature increase of the particles was measured in AC magnetic fields of 64-146 Oe, with an observed temperature increase of ~10 K. Finally, to test the applications of these particles in theranostics, in vitro experiments using human breast cancer cells were conducted.
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http://dx.doi.org/10.1166/jnn.2020.18884DOI Listing
December 2020

Heterogeneous Drug Efficacy of an Antibody-Drug Conjugate Visualized Using Simultaneous Imaging of Its Delivery and Intracellular Damage in Living Tumor Tissues.

Transl Oncol 2020 Jun 11;13(6):100764. Epub 2020 May 11.

Department of Breast and Endocrine Surgical Oncology, Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8574, Japan.

Anticancer drug efficacy varies because the delivery of drugs within tumors and tumor responses are heterogeneous; however, these features are often more homogenous in vitro. This difference makes it difficult to accurately determine drug efficacy. Therefore, it is important to use living tumor tissues in preclinical trials to observe the heterogeneity in drug distribution and cell characteristics in tumors. In the present study, to accurately evaluate the efficacy of an antibody-drug conjugate (ADC) containing a microtubule inhibitor, we established a cell line that expresses a fusion of end-binding protein 1 and enhanced green fluorescent protein that serves as a microtubule plus-end-tracking protein allowing the visualization of microtubule dynamics. This cell line was xenografted into mice to create a model of living tumor tissue. The tumor cells possessed a greater number of microtubules with plus-ends, a greater number of meandering microtubules, and a slower rate of microtubule polymerization than the in vitro cells. In tumor tissues treated with fluorescent dye-labeled ADCs, heterogeneity was observed in the delivery of the drug to tumor cells, and microtubule dynamics were inhibited in a concentration-dependent manner. Moreover, a difference in drug sensitivity was observed between in vitro cells and tumor cells; compared with in vitro cells, tumor cells were more sensitive to changes in the concentration of the ADC. This study is the first to simultaneously evaluate the delivery and intracellular efficacy of ADCs in living tumor tissue. Accurate evaluation of the efficacy of ADCs is important for the development of effective anticancer drugs.
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http://dx.doi.org/10.1016/j.tranon.2020.100764DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218300PMC
June 2020

Automated Quantification of Extranuclear ERα using Phosphor-integrated Dots for Predicting Endocrine Therapy Resistance in HR/HER2 Breast Cancer.

Cancers (Basel) 2019 Apr 12;11(4). Epub 2019 Apr 12.

Department of Medical Physics, Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8574, Japan.

In addition to genomic signaling, Estrogen receptor alpha (ERα) is associated with cell proliferation and survival through extranuclear signaling contributing to endocrine therapy (ET) resistance. However, the relationship between extranuclear ERα and ET resistance has not been extensively studied. We sought to measure extranuclear ERα expression by immunohistochemistry using phosphor-integrated dots (IHC-PIDs) and to assess its predictive value for ET resistance. After quantitative detection of ERα by IHC-PIDs in vitro, we developed "the nearest-neighbor method" to calculate the extranuclear ERα. Furthermore, tissue sections from 65 patients with HR+/HER2- BC were examined by IHC-PIDs, and the total ERα, nuclear ERα, extranuclear ERα PIDs score, and ratio of extranuclear-to-nuclear ERα (ENR) were measured using the novel method. We demonstrate that quantification of ERα using IHC-PIDs exhibited strong correlations to real-time qRT-PCR ( = 0.94) and flow cytometry ( = 0.98). High ERα ENR was significantly associated with poor overall survival ( = 0.048) and disease-free survival (DFS) ( = 0.007). Multivariate analysis revealed that the ERα ENR was an independent prognostic factor for DFS [hazard ratio, 3.8; 95% CI, 1.4-11.8; = 0.006]. Our automated measurement has high accuracy to localize and assess extranuclear ERα. A high ERα ENR in HR/HER2 BC indicates decreased likelihood of benefiting from ET.
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http://dx.doi.org/10.3390/cancers11040526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520781PMC
April 2019

Quantitative analyses of amount and localization of radiosensitizer gold nanoparticles interacting with cancer cells to optimize radiation therapy.

Biochem Biophys Res Commun 2019 01 12;508(4):1093-1100. Epub 2018 Dec 12.

Department of Medical Physics, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan. Electronic address:

Previous studies showed that gold nanoparticles (AuNPs) are useful radiosensitizers which optimize radiation therapy under low-dose radiation. However, the mechanisms of AuNP radiosensitization, including the amount and localization of the AuNPs interacting with cancer cells, has not yet been quantified. To answer these questions, we prepared AuNPs conjugated with anti-human epidermal growth factor receptor type 2 (HER2) antibody via polyethylene glycol (PEG) chains (AuNP-PEG-HER2ab). AuNP-PEG-HER2ab specifically bound to the HER2-expressing cancer cells and entered the cells via endocytosis. Whether endocytosis of AuNP-PEG-HER2ab occurred had no effect on radiosensitization efficacy by AuNP-PEG-HER2ab in vitro. The radiosensitization efficacy in vitro depended on dose of AuNP-PEG-HER2ab or dose of X-ray. Moreover, AuNP-PEG-HER2ab administrated into tumor-bearing mice was localized to both the periphery of the tumor tissue and near the nuclei in cancer cells in tumor deep tissue. The localization of AuNP-PEG-HER2ab in tumor tissues was important factors for in vivo powerful radiosensitization efficacy.
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http://dx.doi.org/10.1016/j.bbrc.2018.12.016DOI Listing
January 2019