Publications by authors named "Takeshi Namekawa"

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.

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Lineage plasticity is a form of therapy-induced drug resistance. In prostate cancer, androgen receptor (AR) pathway inhibitors potentially lead to the accretion of tumor relapse with loss of AR signaling and a shift from a luminal state to an alternate program. However, the molecular and signaling mechanisms orchestrating the development of lineage plasticity under the pressure of AR-targeted therapies are not fully understood.

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Treatment with androgen receptor pathway inhibitors (ARPIs) in prostate cancer leads to the emergence of resistant tumors characterized by lineage plasticity and differentiation toward neuroendocrine lineage. Here, we find that ARPIs induce a rapid epigenetic alteration mediated by large-scale chromatin remodeling to support activation of stem/neuronal transcriptional programs. We identify the proneuronal transcription factor ASCL1 motif to be enriched in hyper-accessible regions.

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Cancers adapt to increasingly potent targeted therapies by reprogramming their phenotype. Here we investigated such a phenomenon in prostate cancer, in which tumours can escape epithelial lineage confinement and transition to a high-plasticity state as an adaptive response to potent androgen receptor (AR) antagonism. We found that AR activity can be maintained as tumours adopt alternative lineage identities, with changes in chromatin architecture guiding AR transcriptional rerouting.

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Tyrosine kinase inhibitors (TKIs) are used as targeted drugs for advanced renal cell carcinoma (RCC), although most cases eventually progress by acquiring resistance. Cancer stemness plays critical roles in tumor aggressiveness and therapeutic resistance, and dipeptidyl peptidase IV (DPP4) has been recently identified as a cancer stemness-related protein. A question arises whether DPP4 contributes to TKI efficacy in RCC.

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Testicular germ cell tumor (GCT) is the most common type of malignancy in young males. Patients with nonseminomatous GCT still have poor prognosis. To identify new therapeutic targets, we generated patient-derived cells (PDCs) and their xenograft (PDCX) models from 3 distinct GCT patients' specimens.

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Acquired chemoresistance is a critical issue for advanced bladder cancer patients during long-term treatment. Recent studies reveal that a fraction of tumor cells with enhanced tumor-initiating potential, or cancer stem-like cells (CSCs), may particularly contribute to acquired chemoresistance and recurrence. Thus, CSC characterization will be the first step towards understanding the mechanisms underlying advanced disease.

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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.

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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.

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Background: Laparoscopic adrenalectomy has been established as a standard surgical method for unilateral primary aldosteronism. Meanwhile, the background characteristics of the patients undergoing adrenalectomy have changed over the last 20 years. The aim of this study was to investigate the changes in hypertension cure rates after laparoscopic adrenalectomy during the last two decades.

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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.

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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.

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Background: Although the perioperative management of patients with pheochromocytoma has been improving recently, severe hypotensive episodes can occur that require postoperative catecholamine support and are challenging to manage. Our aim was to identify the clinical factors that predict prolonged postresection hypotension in patients after laparoscopic adrenalectomy for pheochromocytoma.

Methods: The records of 73 Japanese patients who underwent unilateral laparoscopic adrenalectomy for pheochromocytoma were surveyed retrospectively.

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Background: Although transperineal (TP) prostate biopsy is growing in popularity, its safety has not been evaluated based on extensive studies. We prospectively assessed the adverse events associated with transrectal ultrasound (TRUS)-guided TP 16-core prostate biopsy at a single institution.

Patients And Methods: We enrolled 2,086 males who underwent first-time TRUS-guided TP prostate biopsy under lumbar spinal anesthesia at Chiba Cancer Center between 2009 and 2013.

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Objectives: To investigate the therapeutic outcomes of neoadjuvant and concurrent androgen-deprivation therapy and intensity-modulated radiation therapy with gold marker implantation for intermediate- and high-risk prostate cancer.

Methods: This was a retrospective study of 325 patients with intermediate- or high-risk prostate cancer according to the National Comprehensive Cancer Network guidelines who underwent androgen-deprivation therapy and intensity-modulated radiation therapy (76 Gy) after gold marker implantation between 2001 and 2010.

Results: The 5-year distant metastasis-free survival rate was significantly lower for very high-risk patients than for intermediate- and high-risk patients (82.

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We report the adverse events and efficacy of traditional (4 weeks on 2 weeks off) and alternative sunitinib treatment schedules for Japanese patients with metastatic renal cell carcinoma. We retrospectively investigated 54 patients who received sunitinib for metastatic renal cell carcinoma between May 2006 and June 2012: 32 received a traditional treatment schedule and 22 received an alternative schedule. According to the Memorial Sloan-Kettering Cancer Center risk classification, five patients had favorable prognoses, 42 had intermediate prognoses and seven had poor prognoses.

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Background. The aim of this study was to determine concordance rates for prostatectomy specimens and transrectal needle biopsy samples in various areas of the prostate in order to assess diagnostic accuracy of the transrectal biopsy approach, especially for presurgical detection of cancer in the prostatic apex. Materials and Methods.

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