Browsing by Author "Okui, Tatsuo"

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    Acidic microenvironment and bone pain in cancer-colonized bone
    (SpringerNature, 2015-05-06) Yoneda, Toshiyuki; Hiasa, Masahiro; Nagata, Yuki; Okui, Tatsuo; White, Fletcher A.; Department of Medicine, IU School of Medicine
    Solid cancers and hematologic cancers frequently colonize bone and induce skeletal-related complications. Bone pain is one of the most common complications associated with cancer colonization in bone and a major cause of increased morbidity and diminished quality of life, leading to poor survival in cancer patients. Although the mechanisms responsible for cancer-associated bone pain (CABP) are poorly understood, it is likely that complex interactions among cancer cells, bone cells and peripheral nerve cells contribute to the pathophysiology of CABP. Clinical observations that specific inhibitors of osteoclasts reduce CABP indicate a critical role of osteoclasts. Osteoclasts are proton-secreting cells and acidify extracellular bone microenvironment. Cancer cell-colonized bone also releases proton/lactate to avoid intracellular acidification resulting from increased aerobic glycolysis known as the Warburg effect. Thus, extracellular microenvironment of cancer-colonized bone is acidic. Acidosis is algogenic for nociceptive sensory neurons. The bone is densely innervated by the sensory neurons that express acid-sensing nociceptors. Collectively, CABP is evoked by the activation of these nociceptors on the sensory neurons innervating bone by the acidic extracellular microenvironment created by bone-resorbing osteoclasts and bone-colonizing cancer cells. As current treatments do not satisfactorily control CABP and can elicit serious side effects, new therapeutic interventions are needed to manage CABP. Understanding of the cellular and molecular mechanism by which the acidic extracellular microenvironment is created in cancer-colonized bone and by which the expression and function of the acid-sensing nociceptors on the sensory neurons are regulated would facilitate to develop novel therapeutic approaches for the management of CABP.
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    Bone pain induced by multiple myeloma is reduced by targeting V-ATPase and ASIC3
    (AACR Publications, 2017-03-15) Hiasa, Masahiro; Okui, Tatsuo; Allette, Yohance M; Ripsch, Matthew S; Sun-Wada, Ge-Hong; Wakabayashi, Hiroki; Roodman, G David; White, Fletcher A.; Yoneda, Toshiyuki; Medicine, School of Medicine
    Multiple myeloma (MM) patients experience severe bone pain (MMBP) that is undertreated and poorly understood. In this study, we studied MMBP in an intratibial mouse xenograft model which employs JJN3 human MM cells. In this model, mice develop MMBP associated in bone with increased sprouting of calcitonin gene-related peptide-positive (CGRP+) sensory nerves and in dorsal root ganglia (DRG) with upregulation of phosphorylated ERK1/2 (pERK1/2) and pCREB, two molecular indicators of neuron excitation. We found that JJN3 cells expressed a vacuolar proton pump (V-ATPase) that induced an acidic bone microenvironment. Inhibition of JJN3-colonized bone acidification by a single injection of the selective V-ATPase inhibitor, bafilomycin A1, decreased MMBP, CGRP+ SN sprouting, and pERK1/2 and pCREB expression in DRG. CGRP+ sensory nerves also expressed increased levels of the acid-sensing nociceptor ASIC3. Notably, a single injection of the selective ASIC3 antagonist APETx2 dramatically reduced MMBP in the model. Mechanistic investigations in primary DRG neurons co-cultured with JJN3 cells showed increased neurite outgrowth and excitation inhibited by bafilomycin A1 or APETx2. Further, combining APETx2 with bafilomycin A1 reduced MMBP to a greater extent than either agent alone. Lastly, combining bafilomycin A1 with the osteoclast inhibitor zoledronic acid was sufficient to ameliorate MMBP which was refractory to zoledronic acid. Overall, our results show that osteoclasts and MM cooperate to induce an acidic bone microenvironment that evokes MMBP as a result of the excitation of ASIC3-activated sensory neurons. Further, they present a mechanistic rationale for targeting ASIC3 on neurons along with the MM-induced acidic bone microenvironment as a strategy to relieve MMBP in patients.
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    Contribution of acidic extracellular microenvironment of cancer-colonized bone to bone pain
    (Elsevier, 2015-10) Yoneda, Toshiyuki; Hiasa, Masahiro; Nagata, Yuki; Okui, Tatsuo; White, Fletcher; Department of Medicine, IU School of Medicine
    Solid and hematologic cancer colonized bone produces a number of pathologies. One of the most common complications is bone pain. Cancer-associated bone pain (CABP) is a major cause of increased morbidity and diminishes the quality of life and affects survival. Current treatments do not satisfactorily control CABP and can elicit adverse effects. Thus, new therapeutic interventions are needed to manage CABP. However, the mechanisms responsible for CABP are poorly understood. The observation that specific osteoclast inhibitors can reduce CABP in patients indicates a critical role of osteoclasts in the pathophysiology of CABP. Osteoclasts create an acidic extracellular microenvironment by secretion of protons via vacuolar proton pumps during bone resorption. In addition, bone-colonized cancer cells also release protons and lactate via plasma membrane pH regulators to avoid intracellular acidification resulting from increased aerobic glycolysis known as the Warburg effect. Since acidosis is algogenic for sensory neurons and bone is densely innervated by sensory neurons that express acid-sensing nociceptors, the acidic bone microenvironments can evoke CABP. Understanding of the mechanism by which the acidic extracellular microenvironment is created in cancer-colonized bone and the expression and function of the acid-sensing nociceptors are regulated should facilitate the development of novel approaches for management of CABP. Here, the contribution of the acidic microenvironment created in cancer-colonized bone to elicitation of CABP and potential therapeutic implications of blocking the development and recognition of acidic microenvironment will be described. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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    The HMGB1/RAGE axis induces bone pain associated with colonization of 4T1 mouse breast cancer in bone
    (Elsevier, 2021-02) Okui, Tatsuo; Hiasa, Masahiro; Ryumon, Shoji; Ono, Kisho; Kunisada, Yuki; Ibaragi, Soichiro; Sasaki, Akira; Roodman, G. David; White, Fletcher A.; Yoneda, Toshiyuki; Medicine, School of Medicine
    Bone pain is a common complication of breast cancer (BC) bone metastasis and is a major cause of increased morbidity and mortality. Although the mechanism of BC-associated bone pain (BCABP) remains poorly understood, involvement of BC products in the pathophysiology of BCABP has been proposed. Aggressive cancers secrete damage-associated molecular patterns (DAMPs) that bind to specific DAMP receptors and modulate cancer microenvironment. A prototypic DAMP, high mobility group box 1 (HMGB1), which acts as a ligand for the receptor for advanced glycation end products (RAGE) and toll-like receptors (TLRs), is increased in its expression in BC patients with poor outcomes. Here we show that 4T1 mouse BC cells colonizing bone up-regulate the expression of molecular pain markers, phosphorylated ERK1/2 (pERK) and pCREB, in the dorsal root ganglia (DRGs) innervating bone and induced BCABP as evaluated by hind-paw mechanical hypersensitivity. Importantly, silencing HMGB1 in 4T1 BC cells by shRNA reduced pERK and pCREB and BCABP with decreased HMGB1 levels in bone. Further, administration of a neutralizing antibody to HMGB1 or an antagonist for RAGE, FPS-ZM1, ameliorated pERK, pCREB and BCABP, while a TLR4 antagonist, TAK242, showed no effects. Consistent with these in vivo results, co-cultures of F11 sensory neuron-like cells with 4T1 BC cells in microfluidic culture platforms increased neurite outgrowth of F11 cells, which was blocked by HMGB1 antibody. Our results show that HMGB1 secreted by BC cells induces BCABP via binding to RAGE of sensory neurons and suggest that the HMGB1/RAGE axis may be a potential novel therapeutic target for BCABP.
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    Lactate secreted via MCT4 from bone‑colonizing breast cancer excites sensory neurons via GPR81
    (Spandidos Publications, 2023) Okui, Tatsuo; Hiasa, Masahiro; Hasegawa, Kazuaki; Nakamura, Tomoya; Ono, Kisho; Ibaragi, Soichiro; Kanno, Takahiro; Sasaki, Akira; Yoneda, Toshiyuki; Medicine, School of Medicine
    Breast cancer (BC) bone metastasis causes bone pain (BP), which detrimentally damages the quality of life and outcome of patients with BC. However, the mechanism of BC-BP is poorly understood, and effective treatments are limited. The present study demonstrated a novel mechanism of BC-BP using a mouse model of bone pain, in which mouse (EO771) and human (MDA-MB-231) BC cells were injected in the bone marrow cavity of tibiae. Western blot analysis using sensory nerves, in vivo assessment of cancer pain and in vitro calcium flux analysis were performed. These mice developed progressive BC-BP in tibiae in conjunction with an upregulation of phosphorylated pERK1/2 and cAMP-response element-binding protein (pCREB), which are molecular indicators of neuron excitation, in the dorsal root ganglia (DRG) of sensory nerves. Importantly, mice injected with BC cells, in which the expression of the lactic acid transporter monocarboxylate transporter 4 (MCT4) was silenced, exhibited decreased BC-BP with downregulated expression of pERK1/2 and pCREB in the DRG and reduced circulating levels of lactate compared with mice injected with parental BC cells. Further, silencing of the cell-surface orphan receptor for lactate, G protein-coupled receptor 81 (GPR81), in the F11 sensory neuron cells decreased lactate-promoted upregulation of pERK1/2 and Ca2+ influx, suggesting that the sensory neuron excitation was inhibited. These results suggested that lactate released from BC cells via MCT4 induced BC-BP through the activation of GPR81 of sensory neurons. In conclusion, the activation of GPR81 of sensory neurons by lactate released via MCT4 from BC was demonstrated to contribute to the induction of BC-BP, and disruption of the interactions among lactate, MCT4 and GPR81 may be a novel approach to control BC-BP.
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    A novel PI3K inhibitor iMDK suppresses non-small cell lung Cancer cooperatively with A MEK inhibitor
    (Elsevier, 2015-07-15) Ishida, Naomasa; Fukazawa, Takuya; Maeda, Yutaka; Yamatsuji, Tomoki; Takaoka, Munenori; Haisa, Minoru; Yokota, Etsuko; Shigemitsu, Kaori; Morita, Ichiro; Kato, Katsuya; Matsumoto, Kenichi; Shimo, Tsuyoshi; Okui, Tatsuo; Bao, Xiao-Hong; Hao, Huifang; Grant, Shawn N.; Takigawa, Nagio; Whitsett, Jeffrey A.; Naomoto, Yoshio; Department of Medicine, Division of Hematology and Oncology, IU School of Medicine
    The PI3K–AKT pathway is expected to be a therapeutic target for non-small cell lung cancer (NSCLC) treatment. We previously reported that a novel PI3K inhibitor iMDK suppressed NSCLC cells in vitro and in vivo without harming normal cells and mice. Unexpectedly, iMDK activated the MAPK pathway, including ERK, in the NSCLC cells. Since iMDK did not eradicate such NSCLC cells completely, it is possible that the activated MAPK pathway confers resistance to the NSCLC cells against cell death induced by iMDK. In the present study, we assessed whether suppressing of iMDK-mediated activation of the MAPK pathway would enhance anti-tumorigenic activity of iMDK. PD0325901, a MAPK inhibitor, suppressed the MAPK pathway induced by iMDK and cooperatively inhibited cell viability and colony formation of NSCLC cells by inducing apoptosis in vitro. HUVEC tube formation, representing angiogenic processes in vitro, was also cooperatively inhibited by the combinatorial treatment of iMDK and PD0325901. The combinatorial treatment of iMDK with PD0325901 cooperatively suppressed tumor growth and tumor-associated angiogenesis in a lung cancer xenograft model in vivo. Here, we demonstrate a novel treatment strategy using iMDK and PD0325901 to eradicate NSCLC.
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    SOX2 suppresses CDKN1A to sustain growth of lung squamous cell carcinoma.
    (NPG, 2016) Fukazawa, Takuya; Guo, Minzhe; Ishida, Naomasa; Yamatsuji, Tomoki; Takaoka, Munenori; Yokota, Etsuko; Haisa, Minoru; Miyake, Noriko; Ikeda, Tomoko; Okui, Tatsuo; Takigawa, Nagio; Maeda, Yutaka; Naomoto, Yoshio; Department of Medicine, IU School of Medicine
    Since the SOX2 amplification was identified in lung squamous cell carcinoma (lung SCC), SOX2 transcriptional downstream targets have been actively investigated; however, such targets are often cell line specific. Here, in order to identify highly consensus SOX2 downstream genes in lung SCC cells, we used RNA-seq data from 178 lung SCC specimens (containing tumor and tumor-associated cells) and analyzed the correlation between SOX2 and previously-reported SOX2-controlled genes in lung SCC. In addition, we used another RNA-seq dataset from 105 non-small cell lung cancer cell lines (NSCLC; including 4 lung SCC cell lines) and again analyzed the correlation between SOX2 and the reported SOX2-controlled genes in the NSCLC cell lines (no tumor-associated cells). We combined the two analyses and identified genes commonly correlated with SOX2 in both datasets. Among the 99 genes reported as SOX2 downstream and/or correlated genes, we found 4 negatively-correlated (e.g., CDKN1A) and 11 positively-correlated genes with SOX2. We used biological studies to demonstrate that CDKN1A was suppressed by SOX2 in lung SCC cells. G1 cell cycle arrest induced by SOX2 siRNA was rescued by CDKN1A siRNA. These results indicate that the tumorigenic effect of SOX2 in lung SCC cells is mediated in part by suppression of CDKN1A.