Yasuyuki Ikezawa

Endobronchial Ultrasonography with a Guide Sheath for Pure or Mixed Ground-Glass Opacity Lesions

Background: Ground-glass opacity (GGO) lesions are difficult to diagnose by transbronchial biopsy (TBB). Objectives: We attempted to diagnose solitary peripheral GGO predominant-type lesions by TBB using endobronchial ultrasonography with a guide sheath (EBUS-GS) under X-ray fluoroscopic guidance, and to evaluate several factors associated with diagnostic yield. Methods: The medical records of 67 patients with GGO predominant-type lesions who underwent TBB using EBUS-GS under X-ray fluoroscopic guidance were retrospectively reviewed. Results: Of the 67 lesions, 38 (57%) were successfully diagnosed by EBUS-GS (5/11 pure GGO lesions and 33/56 mixed GGO lesions). The diagnosable lesions were significantly larger than the nondiagnosable lesions (24 vs. 17 mm, respectively; p < 0.01). Regarding the diagnostic yield by signs on computed tomography, the lesions with a bronchus leading directly to a lesion had a significantly higher diagnostic yield than the others (p < 0.05). When GGO lesions were confirmed under X-ray fluoroscopic guidance, the diagnostic yield was 79% (vs. 40% in lesions not visible on X-ray fluoroscopy; p < 0.05). Conclusions: EBUS-GS is a useful and valuable diagnostic modality, even for GGO predominant-type lesions located at the lung periphery.

Combined antitumor effect of γ-secretase inhibitor and ABT-737 in Notch-expressing non-small cell lung cancer

BackgroundInhibition of Notch by γ-secretase inhibitor (GSI) has been shown to have an antitumor effect in Notch-expressing non-small cell lung cancer (NSCLC) and to induce apoptosis through modulation of Bcl-2 family proteins. In particular, Bim, a BH3-only member of the Bcl-2 family of proteins, has an important role in the induction of apoptosis in NSCLC when cells are treated with GSI. ABT-737, a BH3-only mimetic, targets the pro-survival Bcl-2 family and also induces apoptosis.MethodsThe Notch-expressing NSCLC cell lines H460, A549, H1793, and HCC2429 were used. The combined antitumor effect of GSI and ABT-737 was evaluated using the MTT proliferation assay in vitro and in xenograft mouse models. The expression of the Notch pathway and Bcl-2 family was analyzed using Western blotting analysis when cells were treated with a single drug treatment or a combination treatment.ResultsGSI XX or ABT-737 alone inhibited cell proliferation in a dose-dependent manner, and combination drug treatment showed a synergistic antitumor effect in vitro. In vivo, this drug combination significantly suppressed tumor proliferation compared to the single drug treatment. Phospho-Bcl-2 was downregulated and Bax was upregulated by both the single and combination drug treatments. Bim was induced by a single drug treatment and was enhanced by combination treatment. Combination treatment-induced apoptosis was decreased by Bim inhibition, suggesting that the antitumor effect of the drug combination was dependent on Bim.ConclusionBased on our data, we propose that the combination treatment is a promising strategy for NSCLC therapy.

Successful Application of Edoxaban in the Treatment of Venous Thromboembolism Recurrence in a Patient with Non-small Cell Lung Cancer after Tumor Shrinkage

This report describes the case of a 66-year-old man with non-small cell lung cancer and venous thromboembolism (VTE). Unfractionated heparin (UFH) was initially used to control VTE before chemotherapy. However, switching UFH to warfarin or edoxaban, a novel oral anticoagulant (NOAC), failed. Chemotherapy was then administered to control the tumor which was thought to have been the main cause of VTE, which had been treated by UFH. After tumor shrinkage was achieved by chemotherapy, we were able to successfully switch from UFH to edoxaban. Controlling the tumor size and activity enabled the use of edoxaban as maintenance therapy for VTE.

Abstract 1172: Expression of notch1, numb, and musashi1 in non-small cell lung cancer

Background: Deregulation of Notch pathway is associated with carcinogenesis, and Notch signaling is identified as tumor activator in non-small cell lung cancer(NSCLC). The function of Musashi1 has been found to activate Notch signaling through the translational repression of Numb, which represses an intracellular Notch signaling. In NSCLC, the association between Numb or Musashi1 expression and clinicopathological factors or prognosis has remained unclear. In this study, we evaluated the expression of Notch1, Numb, and Musashi1 in NSCLC. Methods: A total of 135 surgically resected NSCLCs were immunohistochemically assessed for Notch1, Numb, and Musashi1 expression. Only cytoplasm and nuclear staining was considered in the evaluation of activated Notch1 expression. The immunoscores were determined, and then its correlation with either the clinicopathological variables or the survival outcomes was analyzed. Results: Immunohistochemical reactivity for Numb, and Musashi1 was detected in the cytoplasm and nuclear of the tumor cells. Notch1 expression was associated with several clinicopathological factors, including pathological histology (p = 0.002), and differentiation of tumor (p = 0.024). Numb expression was also associated with several clinicopathological factors, including sex (p = 0.037), smoking habit (p = 0.033), pathological histology (p = 0.002), and differentiation of tumor (p = 0.015). No correlations were noted between Musashi1 expression and any of the variables. Analysis of cellular biological expression demonstrated a link between low Numb expression and high Notch expression. Multivariate Cox regression analysis showed that positive Numb expression was an independent favorable prognostic factor. Conclusions: We demonstrate that Numb expression was associated with better prognosis in NSCLC. Numb might have the function as tumor suppressor in NSCLC. Citation Format: Hajime Kikuchi, Jun Sakakibara-Konishi, Yasuyuki Ikezawa, Taichi Takashina, Hidenori Mizugaki, Eiki Kikuchi, Junko Kikuchi, Naofumi Shinagawa, Satoshi Oizumi, Yasuhiro Hida, Kichizo Kaga, Ichiro Kinoshita, Hirotoshi Dosaka-Akita, Masaharu Nishimura. Expression of notch1, numb, and musashi1 in non-small cell lung cancer. [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 1172.

Abstract 3937: Inhibition of Notch and HIF enhances the antitumor effect of radiation in Notch expressing lung cancer

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Background: Notch pathway regulates cell-fate determination in multi-cellular organisms and aberrant activation of Notch pathway has been reported in tumorigenesis of many cancers. We previously reported that Notch3 and its downstream effector, HEY1, were up-regulated by radiation in non-small cell lung cancer (NSCLC) cell lines. Furthermore, we demonstrated that g secretase inhibitor (GSI), when combined with radiation therapy, significantly suppressed the growth of lung cancer cells compared with either GSI or radiation alone. The proposed mechanism involves GSI suppressing radiation-induced Notch activation and the resultant radioresistance. However, little is known about the mechanism of Notch up-regulation induced by radiation. Since the expression of Notch was reported to be activated via HIF under hypoxia, we, in this study, hypothesized that HIF would be involved in radiation-induced Notch activation in NSCLC and thus HIF inhibitor (YC-1) would have an anti-tumor effect when combined with radiation therapy as is the case with GSI. Materials and Methods: Two Notch-expressing lung cancer cell lines (H460 and HCC2429) were used. We first examined the changes in expressions of HIF pathway and Notch family after radiation under hypoxia using Western blotting (WB) and real time RT-PCR.Notch expression was evaluated after HIF-1α suppression by siRNA targeting HIF-1α. Next, in vitro we investigated an antitumor effect of YC-1, using a MTT proliferation assay and a clonogenic assay, when combined with radiation. And the combined antitumor effect of GSI and YC-1 with radiation was examined using the Fa-CI plot of isobologram analysis. Finally, we utilized a xenograft model and resected some tumors on day 15 for molecular analysis. Results: Under hypoxia, the expression of HIF-1α was up-regulated when the cells were incubated for 6 h without radiation. Radiation up-regulated the expression of Notch3 and VEGF at 24 h compared with control. Specific suppression of HIF-1α by siRNA down-regulated Notch3 and Hey1 activation associated with radiation. In vitro, IC50 of YC-1 and colony formation were decreased only when radiation treatment was concurrently applied under hypoxia compared with sequential treatment. Moreover, GSI and YC-1 had a synergistic antitumor effect under hypoxia without or with radiation. In vivo, combination of GSI and YC-1 showed the greatest radiosensitivity and reduced radiation-induced Notch activation in molecular analysis, compared with single treatment. Conclusions: Radiation-induced up-regulation of Notch pathway and HIF-1α might provide therapeutic targets for more effective radiation therapy in NSCLC. Citation Format: Yasuyuki Ikezawa, Jun Sakakibara-Konishi, Hidenori Mizugaki, Satoshi Oizumi, Masaharu Nishimura. Inhibition of Notch and HIF enhances the antitumor effect of radiation in Notch expressing lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3937. doi:10.1158/1538-7445.AM2014-3937

Abstract 435: The role of HIF-1 and Notch pathway in radio-resistance of non small lung cancer cell lines.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background: Notch pathway regulates cell-fate determination in multi-cellular organisms and aberrant activation of Notch pathway has been reported in tumorigenesis of many cancers. We previously reported that Notch3 and its downstream effector, HEY1, were upregulated by radiation in non-small cell lung cancer (NSCLC) cell lines. Furthermore, we demonstrated that g-secretase-inhibitor (GSI), when combined with radiation therapy significantly suppressed the growth of lung cancer cells compared to either GSI or radiation alone by a potential mechanism that GSI suppressed radiation-induced Notch activation and its resultant radio-resistance. Since the expression of Notch was reported to be activated via HIF under hypoxia, we, in this study, hypothesized that HIF would be involved in radiation-induced Notch activation in NSCLC and thus HIF inhibitor (YC-1) would have an anti-tumor effect when combined with radiation therapy as is the case with GSI. Materials and Methods: Two Notch-expressing lung cancer cell lines (H460 and H1793) were used. We first examined, by Western Blotting (WB) and real time RT-PCR, the changes in expressions of HIF-1 and Notch family after treatment by radiation under hypoxia. We then repeated the same experiment while using SiRNA targeting HIF-1, in an attempt to examine the role of HIF-1 on Notch pathway and its downstream proteins. Finally, we investigated an antitumor effect of YC-1, using a MTT proliferation assay and a clonogenic assay, when combined with radiation treatment. Results: Under hypoxia, treatment by radiation up-regulated protein expression of HIF-1 at 6 hours and that of Notch3 as well at 24 hours, but not of other Notch family. As expected, specific suppression of HIF-1 by siRNA down-regulated Notch3 activation associated with radiation; however, did not affect other Notch family and its downstream effectors, including HES1. An anti-tumor effect of YC-1 was evident only when radiation treatment was concurrently applied, but not when sequentially applied, in the growth of lung cancer cells and also colony formation. Conclusions: Radiation-induced up-regulations of HIF-1 and Notch pathway may be therapeutic targets for more effective radiation therapy in NSCLC. Citation Format: Yasuyuki Ikezawa, Jun Sakakibara-Konishi, Hidenori Mizugaki, Satoshi Ooizumi, Masaharu Nishimura. The role of HIF-1 and Notch pathway in radio-resistance of non small lung cancer cell lines. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 435. doi:10.1158/1538-7445.AM2013-435