Akiko Ishida

Selective enhancement of bleomycin cytotoxicity by local anesthetics.

Abstract The cytotoxic effect of the antitumor antibiotic bleomycin toward cultured mouse FM3A cells was greatly enhanced by exposure of the cells to local anesthetics either before or together with treatment with bleomycin. Such local anesthetics include dibucaine, tetracaine, butacaine, lidocaine and procaine. Dibucaine-induced cell sensitization to bleomycin cytotoxicity produced a decrease in cell survival that became dependent on dose and time of bleomycin treatment. This effect of local anesthetics seems to be selective to bleomycin, since dibucaine and lidocaine do not enhance the cytotoxic effect of other antitumor agents including adriamycin, mitomycin C and cis -diamminedichloroplatinum(II).

Potentiation of bleomycin cytotoxicity by membrane-interacting drugs and increased calcium ions.

Abstract The cytotoxic effect of the antitumor antibiotic peplomycin (PEP), a new member of bleomycin group antibiotics, toward HeLa cells and mouse FM3A cells is enhanced by some membrane-interacting drugs such as verapamil, persantin, prenylamine, chlorpromazine and anafranil. The enhancing action of verapamil is selective to this group antibiotics, since it does not potentiate the cytotoxic effects of vincristine, adriamycin, mitomycin C, cis -diamminedichloroplatinum(II) and macromomycin. An enhanced PEP cytotoxicity has been also demonstrated by the treatment of cells in the presence of increased CaCl 2 . This enhancing effect of increased CaCl 2 is prevented by the Ca 2+ transport inhibitor ruthenium red. Since these membrane-directed drugs have been shown to affect Ca 2+ metabolism, we conclude that potentiation of PEP cytotoxicity by these drugs is mediated by an increase in intracellular Ca 2+ .

Polymorphic structures and molecular vibrations of linear oligomers of polyoxymethylene studied by polarized infrared and Raman spectra measured on single crystals

Abstract Molecular vibrations of linear oligomers of polyoxymethylene (POM) having acetoxyl groups at the chain ends, CH 3 CO 2 (CH 2 ,O) m COCH 3 (POMA cm ) with m = 10 and 11, were investigated by means of polarized infrared and Raman spectra taken on single-crystal specimens. From the spectral data obtained for solution-grown crystals of POMAc10 consisting of the orthorhombic POM (o-POM) sublattice, the dispersion curves for the ν 6 through ν 9 branches of the (2/1) helix of the POM molecule were obtained. POMAc10 crystals grown from the melt gave rise to spectra characteristic of the (9/5) helices adapted to the trigonal POM (t-POM) sublattice, indicating that the trigonal packing of the (9/5) helices is more stable than the orthorhombic arrangement of the (2/1) helices at a high-temperature range. Using the spectral data of a POMAc11 crystal consisting of the t-POM sublattice, combined with those of melt-grown POMAc10, the ν 6 through ν 9 dispersion curves of t-POM were obtained. For these oligomers it was found that the frequencies of the infrared-active zone-center modes having the transition dipoles parallel to the chain axis exhibited remarkable shifts depending on the inclination of the molecules to the lamella face of molecular layers, as predicted from the transition dipolar coupling theory.

2-aminoethoxydiphenyl borate provides an anti-oxidative effect and mediates cardioprotection during ischemia reperfusion in mice

Excessive levels of reactive oxygen species (ROS) and impaired Ca2+ homeostasis play central roles in the development of multiple cardiac pathologies, including cell death during ischemia-reperfusion (I/R) injury. In several organs, treatment with 2-aminoethoxydiphenyl borate (2-APB) was shown to have protective effects, generally believed to be due to Ca2+ channel inhibition. However, the mechanism of 2-APB-induced cardioprotection has not been fully investigated. Herein we investigated the protective effects of 2-APB treatment against cardiac pathogenesis and deciphered the underlying mechanisms. In neonatal rat cardiomyocytes, treatment with 2-APB was shown to prevent hydrogen peroxide (H2O2) -induced cell death by inhibiting the increase in intracellular Ca2+ levels. However, no 2-APB-sensitive channel blocker inhibited H2O2-induced cell death and a direct reaction between 2-APB and H2O2 was detected by 1H-NMR, suggesting that 2-APB chemically scavenges extracellular ROS and provides cytoprotection. In a mouse I/R model, treatment with 2-APB led to a considerable reduction in the infarct size after I/R, which was accompanied by the reduction in ROS levels and neutrophil infiltration, indicating that the anti-oxidative properties of 2-APB plays an important role in the prevention of I/R injury in vivo as well. Taken together, present results indicate that 2-APB treatment induces cardioprotection and prevents ROS-induced cardiomyocyte death, at least partially, by the direct scavenging of extracellular ROS. Therefore, administration of 2-APB may represent a promising therapeutic strategy for the treatment of ROS-related cardiac pathology including I/R injury.

Blocking the FSTL1-DIP2A Axis Improves Anti-tumor Immunity.

Immune dysfunction is a strong factor in the resistance of cancer to treatment. Blocking immune checkpoint pathways is a promising approach to improve anti-tumor immunity, but the clinical efficacies are still limited. We previously identified follistatin-like 1 (FSTL1) as a determinant of immune dysfunction mediated by mesenchymal stromal/stem cells (MSCs) and immunoregulatory cells. Here, we demonstrate that blocking FSTL1 but not immune checkpoint pathways significantly suppresses cancer progression and metastasis in several mouse tumor models with increased MSCs. Expression of DIP2A (the receptor of FSTL1) in tumor cells is critical for FSTL1-induced immunoresistance. FSTL1/DIP2A co-positivity in tumor tissues correlates with poor prognosis in NSCLC patients. Thus, breaking the FSTL1-DIP2A axis may be a useful strategy for successfully inducing anti-tumor immunity.

Abstract 3224: Blocking FSTL1 reprograms cancer-caused abnormal immunity

Purposes: The close connection between imbalanced immunity and tumor progression has been increasingly recognized, and a number of inhibitors for blocking immune inhibitory checkpoints have been established to improve the anti-tumor immunity in cancer patients. However, clinical responses are limited to a part of the treated patients. We previously identified FSTL1, which is significantly secreted from Snail+ metastatic tumor cells, as a key effector molecule in the cancer-caused immune suppression and dysfunction. FSTL1 generates and expands pluripotent mesenchymal stem cells (MSCs), which are able to generate various immunoregulatory cells and functionally impaired CD8-low T cells, and also to induce de novo tumor dissemination into bone marrow. FSTL1 also directly confers higher invasiveness on tumor cells (EMT induction). To prevent the FSTL1-caused vicious circulation for tumor progression, we attempted to establish anti-FSTL1 blocking mAbs. Results: We generated chicken/mouse chimeric anti-FSTL1 mAbs, which specifically recognized human and mouse FSTL1. The anti-FSTL1 mAb significantly suppressed tumor proliferation and invasion, MSC induction in mouse bone marrow cells, and Treg induction in human PBMCs in vitro as compared to the control group. When bone metastatic melanoma models (C57BL/6 mice implanted with snail-transduced B16-F10 melanoma cells both subcutaneously and intravenously) were intraperitoneally injected with the anti-FSTL1 mAb (10 mg/kg) on Day 5 (when tumor metastasis was already observed in bone marrow) and Day 10 after tumor implantation, the FSTL1-caused events were inhibited, and tumor-specific CD8+ T cells with higher CTL activities were generated, resulting in significant suppression of subcutaneous tumor growth and bone metastasis in the treated mice as compared to those of the control mice. At least in the same models, conventional immune checkpoint inhibitors including anti-CTLA4, anti-PD1, and anti-PDL1 mAbs failed to improve the anti-tumor immunity, and rather promoted bone metastasis because of no reduction of regulatory cells, particularly the MSCs in the treated mice. Conclusions: These results suggest that blocking FSTL1 reprograms and properly induces anti-tumor immunity by switching the tumor-supportive immune directivity to the active mode against cancer. Our anti-FSTL1 mAb having totally different molecular mechanisms from the conventional ones may be a promising therapeutics as a next generation of “immune checkpoint inhibitors” for radically correcting cancer-manipulated immunity in clinical settings. Citation Format: Chie Kudo-Saito, Masayoshi Toyoura, Yuji Shoya, Akiko Ishida, Ryoko Kon. Blocking FSTL1 reprograms cancer-caused abnormal immunity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3224.