TAKESHI NAMEKAWA

Dr. TAKESHI NAMEKAWA

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 January 2019 in Cells
Verified
Journal Article
Open access
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TNTAKESHI NAMEKAWA
TAKESHI NAMEKAWA
KIKazuhiro Ikeda
Kazuhiro Ikeda
KHKuniko Horie
Kuniko Horie
Satoshi InoueSatoshi Inoue
Satoshi Inoue
Various preclinical models have been developed to clarify the pathophysiology of prostate cancer (PCa). Traditional PCa cell lines from clinical metastatic lesions, as exemplified by DU-145, PC-3, and LNCaP cells, are useful tools to define mechanisms underlying tumorigenesis and drug resistance. Cell line-based experiments, however, have limitations for preclinical studies because those cells are basically adapted to 2-dimensional monolayer culture conditions, in which the majority of primary PCa cells cannot survive. Recent tissue engineering enables generation of PCa patient-derived xenografts (PDXs) from both primary and metastatic lesions. Compared with fresh PCa tissue transplantation in athymic mice, co-injection of PCa tissues with extracellular matrix in highly immunodeficient mice has remarkably improved the success rate of PDX generation. PDX models have advantages to appropriately recapitulate the molecular diversity, cellular heterogeneity, and histology of original patient tumors. In contrast to PDX models, patient-derived organoid and spheroid PCa models in 3-dimensional culture are more feasible tools for in vitro studies for retaining the characteristics of patient tumors. In this article, we review PCa preclinical model cell lines and their sublines, PDXs, and patient-derived organoid and spheroid models. These PCa models will be applied to the development of new strategies for cancer precision medicine.

22 May 2018 in Reproductive Medicine and Biology
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Journal Article
Open access
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TNTAKESHI NAMEKAWA
TAKESHI NAMEKAWA
TITakashi Imamoto
Takashi Imamoto
MKMayuko Kato
Mayuko Kato
AKAkira Komiya
Akira Komiya
TITomohiko Ichikawa
Tomohiko Ichikawa
Background: In the era of improving assisted reproductive technology (ART), patients with obstructive azoospermia (OA) have 2 options: vasal repair or testicular sperm extraction with intracytoplasmic sperm injection. Vasal repair, including vasovasostomy (VV) and vasoepididymostomy (VE), is the only option that leads to natural conception.Methods: This article reviews the surgical techniques, outcomes, and predictors of postoperative patency and pregnancy, with a focus on articles that have reported over the last 10 years, using PubMed database searches.Main findings: The reported mean patency rate was 87% and the mean pregnancy rate was 49% for a patient following microscopicVVand/orVEfor vasectomy reversal. Recently, robot‐assisted techniques were introduced and have achieved a high rate of success. The predictors and predictive models of postoperative patency and pregnancy also have been reported. The obstructive interval, presence of a granuloma, and intraoperative sperm findings predict postoperative patency. These factors also predict postoperative fertility. In addition, the female partner's age and the same female partner correlate with pregnancy after surgery.Conclusion: In the era ofART, the physician should present and discuss with both the patient withOAand his partner the most appropriate procedure to conceive by using these predictors.

29 October 2024 in JCI Insight
Verified
Journal Article
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SNShaghayegh Nouruzi
Shaghayegh Nouruzi
TNTAKESHI NAMEKAWA
TAKESHI NAMEKAWA
NTNakisa Tabrizian
Nakisa Tabrizian
MKMaxim Kobelev
Maxim Kobelev
OSOlena Sivak
Olena Sivak
AZAmina Zoubeidi
Amina Zoubeidi
Lineage plasticity mediates resistance to androgen receptor pathway inhibitors (ARPIs) and progression from adenocarcinoma to neuroendocrine prostate cancer (NEPC), a highly aggressive and poorly understood subtype. Neuronal transcription factor ASCL1 has emerged as a central regulator of the lineage plasticity driving neuroendocrine differentiation. Here, we showed that ASCL1 was reprogrammed in ARPI-induced transition to terminal NEPC and identified that the ASCL1 binding pattern tailored the expression of lineage-determinant transcription factor combinations that underlie discrete terminal NEPC identity. Notably, we identified FOXA2 as a major cofactor of ASCL1 in terminal NEPC, which is highly expressed in ASCL1-driven NEPC. Mechanistically, FOXA2 and ASCL1 interacted and worked in concert to orchestrate terminal neuronal differentiation. We identified that prospero homeobox 1 was a target of ASCL1 and FOXA2. Targeting prospero homeobox 1 abrogated neuroendocrine characteristics and led to a decrease in cell proliferation in vitro and tumor growth in vivo. Our findings provide insights into the molecular conduit underlying the interplay between different lineage-determinant transcription factors to support the neuroendocrine identity and nominate prospero homeobox 1 as a potential target in ASCL1-high NEPC.


1 July 2016 in Asian Journal of Surgery
Verified
Journal Article
Open access
TNTAKESHI NAMEKAWA
TAKESHI NAMEKAWA
TUTakanobu Utsumi
Takanobu Utsumi
TITakashi Imamoto
Takashi Imamoto
KKKoji Kawamura
Koji Kawamura
TOTakashi Oide
Takashi Oide
TITomohiko Ichikawa
Tomohiko Ichikawa
Adrenal tumors with more than one cellular component are uncommon. Furthermore, an adrenal tumor composed of a pheochromocytoma and a malignant peripheral nerve sheath tumor is extremely rare. A composite pheochromocytoma with malignant peripheral nerve sheath tumor in a 42-year-old man is reported here. After adequate preoperative control, left adrenalectomy was performed simultaneously with resection of the ipsilateral kidney for spontaneous rupture of the left adrenal tumor. Pathological findings demonstrated pheochromocytoma and malignant peripheral nerve sheath tumor in a ruptured adrenal tumor. To date, there have been only four reported cases of composite pheochromocytoma with malignant peripheral nerve sheath tumor, so the present case is only the fifth case in the world. Despite the very poor prognosis of patients with pheochromocytoma and malignant peripheral nerve sheath tumors reported in the literature, the patient remains well without evidence of recurrence or new metastatic lesions at 36 months postoperatively.

31 December 2015 in Reproductive Medicine and Biology
Verified
Journal Article
Open access
PDF file
TNTAKESHI NAMEKAWA
TAKESHI NAMEKAWA
TITakashi Imamoto
Takashi Imamoto
MKMayuko Kato
Mayuko Kato
TSTomokazu Sazuka
Tomokazu Sazuka
MFMiki Fuse
Miki Fuse
TITomohiko Ichikawa
Tomohiko Ichikawa
Purpose: The aim of our study was to identify the clinical predictors of spermatogenesis recovery in testicular cancer (TC) patients after chemotherapy and to determine the recuperation period for spermatogenesis.Methods: Patients treated for TC from January 1982 to November 2001 at Chiba University Hospital were retrospectively assessed. Thirty‐five patients who met the following criteria were examined—(i) underwent both high orchiectomy and cisplatin‐based chemotherapy; (ii) had semen analyses and hormonal measurements; and (iii) were alive with no evidence of disease. Clinical variables associated with normalization of spermatogenesis after chemotherapy were examined. Time to recover normospermia was also evaluated using Kaplan–Meier analysis.Results: The observation period was 13.3 ± 5.6 years. Reappearance of sperm was confirmed in 85.7 % of patients, and 54.3 % of patients recovered normospermia. Age at diagnosis <25 years (p = 0.0057), number of chemotherapy cycles <4 cycles (p = 0.0042), and follicle‐stimulating hormone at the end of chemotherapy <18 mIU/ml (p = 0.0220) were independent factors related to post‐chemotherapy normalization of semen findings. The median (95 % CI) time to recover normospermia was 40 (range 22–96) months.Conclusions: These findings help to predict whether spermatogenesis will recover and its timing. They may also help clinicians identify and manage TC patients at a higher risk of prolonged azoospermia after chemotherapy.