Association between recovery from desaturation after stair climbing and postoperative complications in lung resection.

OBJECTIVE: The stair-climbing test (SCT) is used as a surrogate for cardiopulmonary exercise testing, which measures maximal oxygen uptake, and considered a useful method for assessing exercise capacity in thoracic surgery. This study aims to investigate whether the recovery time of percutaneous oxygen saturation (SpO2) after stair climbing is a predictor of postoperative complications after lobectomy. METHODS: We retrospectively identified 54 patients who performed SCT and underwent lobectomy between January 2015 and February 2023 at Shizuoka Cancer Center. The SpO2 recovery time was defined as the time required to recover from the minimum to resting value after stair climbing. The association between SpO2 recovery time and early postoperative pulmonary complications within 30 days after surgery was analyzed. RESULTS: Eleven patients (20.4%) had postoperative pulmonary complications (≥ Clavien-Dindo Classification Grade 2). The cutoff value of SpO2 recovery time obtained from the receiver operating characteristic curve analysis was 90 s [sensitivity, 81.8%; specificity, 72.1%; AUC, 0.77 (95% confidence interval, 0.64-0.90)]. The occurrence of postoperative pulmonary complications was 42.9% in the delayed recovery time (DRT; SpO2 recovery time ≥ 90 s) group and 6.1% in the non-DRT (SpO2 recovery time < 90 s) group (p = 0.002). DRT was a predictor of postoperative pulmonary complications (odds ratio, 11.60; 95% CI 2.19-61.80). CONCLUSIONS: DRT of SpO2 after stair climbing is a predictor of postoperative pulmonary complications following lobectomy in borderline patients who require exercise capacity assessment. SpO2 monitoring after stair climbing may be useful as one of the preoperative assessments in patients undergoing lobectomy.

Hepatopancreatoduodenectomy with delayed division of the pancreatic parenchyma when utilizing a right lateral approach to the superior mesenteric artery.

BACKGROUND: Hepatopancreatoduodenectomy (HPD) is a high-risk surgical procedure. Delayed division of the pancreatic parenchyma (DDPP) was reported as a novel technique in HPD for reducing postoperative pancreatic fistula. However, it is often difficult to dissect the pancreatic head nerve plexus while leaving the pancreatic parenchyma intact, particularly in patients with a bulky tumor with vascular invasion. Of the various reported approaches to the superior mesenteric artery, the right lateral approach can provide a useful surgical field to conduct DDPP in HPD. CASE PRESENTATION: A 78-year-old man visited a local clinic with itching and jaundice. Laboratory tests revealed elevated hepatobiliary enzyme, total bilirubin, and tumor markers. Enhanced computed tomography, endoscopic retrograde cholangiopancreatography, and intraductal ultrasonography of the bile duct were performed, and he was diagnosed with perihilar cholangiocarcinoma with invasion to the right hepatic artery (40 × 15 mm, Bismuth IIIa, cT3N0M0 cStage III). After neoadjuvant chemotherapy, he underwent left hepatectomy with caudate lobectomy, pancreatoduodenectomy, and combined resection of right hepatic artery using DDPP with a right lateral approach to the superior mesenteric artery. The pathological diagnosis was perihilar cholangiocarcinoma ypT3N1M0 ypStage IIIC, R0 resection. He was discharged on postoperative day 57 in good health and has been doing well for 6 months since the surgery. CONCLUSIONS: We present an effective application of the right lateral approach to the superior mesenteric artery in DDPP during HPD. This procedure can provide a clear surgical field to easily divide the pancreatic head nerve plexus before transection of the pancreatic parenchyma.

SF6 is a useful expander for post-pneumonectomy syndrome in the long-term course: a case report.

BACKGROUND: Post-pneumonectomy syndrome (PPS) is a rare but serious condition that can occur after pneumonectomy. It is characterized by a mediastinal shift towards the vacated hemithorax, which can potentially lead to respiratory failure. The management of PPS poses a clinical challenge, especially in the context of the limited availability of certain therapeutic devices due to regulatory restrictions in Japan. CASE PRESENTATION: A 36-year-old female with stage IB non-small cell lung cancer underwent left pneumonectomy. Approximately 2 years later, she developed dyspnea. After consulting with our hospital, subsequent imaging revealed an extreme mediastinal shift causing bronchial obstruction. Emergency thoracotomy and subsequent sulfur hexafluoride (SF6) injections were successfully used to manage her condition. Over the course of follow-up, the interval between SF6 injections was extended from 3 to 11 months, indicating an improvement in the intrathoracic condition. CONCLUSIONS: This case illustrates the efficacy of SF6 gas in treating PPS and in reducing the frequency of medical interventions. SF6 gas administration is safe and effective for the treatment of patients with PPS.

An Antibody of the Secreted Isoform of Disintegrin and Metalloprotease 9 (sADAM9) Inhibits Epithelial-Mesenchymal Transition and Migration of Prostate Cancer Cell Lines.

Prostate cancer (PC) is the most common cancer diagnosed in men worldwide. Currently, castration-resistant prostate cancer (CRPC), which is resistant to androgen deprivation therapy, has a poor prognosis and is a therapeutic problem. We investigated the antitumor effects on PC of an antibody neutralizing secreted disintegrin and metalloproteinase domain-containing protein 9 (sADAM9), which is a blood-soluble form. We performed proliferation assays, wound healing assays, invasion assays, Western blot (WB), and an in vivo study in which a sADAM9 neutralizing antibody was administered intratumorally to PC-bearing mice. In invasion assays, the sADAM9 neutralizing antibody significantly inhibited invasion in all cell lines (TRAMP-C2: p = 0.00776, LNCaP: p = 0.000914, PC-3: p = 0.0327, and DU145: p = 0.0254). We examined epithelial-mesenchymal transition (EMT) markers, one of the metastatic mechanisms, in WB and showed downregulation of Slug in TRAMP-C2, LNCaP, and DU145 and upregulation of E-cadherin in TRAMP-C2 and PC-3 by sADAM9 neutralization. In mouse experiments, the sADAM9 neutralizing antibody significantly suppressed tumor growth compared to controls (1.68-fold in TRAMP-C2, 1.89-fold in LNCaP, and 2.67-fold in PC-3). These results suggested that the sADAM9 neutralizing antibody inhibits invasion, migration, and tumor growth in PC. Previous studies examined the anti-tumor effect of knockdown of total ADAM9 or sADAM9, but this study used the new technology of neutralizing antibodies for sADAM9. This may be novel because there was no animal study using a neutralizing antibody for sADAM9 to see the relationship between ADAM9 expression and prostate cancer.

Establishment of an artificial urine model in vitro and rat or pig model in vivo to evaluate urinary crystal adherence.

The current study aimed to establish an experimental model in vitro and in vivo of urinary crystal deposition on the surface of ureteral stents, to evaluate the ability to prevent crystal adhesion. Non-treated ureteral stents were placed in artificial urine under various conditions in vitro. In vivo, ethylene glycol and hydroxyproline were administered orally to rats and pigs, and urinary crystals and urinary Ca were investigated by Inductively Coupled Plasma-Optical Emission Spectrometer. in vitro, during the 3- and 4-week immersion periods, more crystals adhered to the ureteral stent in artificial urine model 1 than the other artificial urine models (p < 0.01). Comparing the presence or absence of urea in the composition of the artificial urine, the artificial urine without urea showed less variability in pH change and more crystal adhesion (p < 0.05). Starting the experiment at pH 6.3 resulted in the highest amount of crystal adhesion to the ureteral stent (p < 0.05). In vivo, urinary crystals and urinary Ca increased in rat and pig experimental models. This experimental model in vitro and in vivo can be used to evaluate the ability to prevent crystal adhesion and deposition in the development of new ureteral stents to reduce ureteral stent-related side effects in patients.

Xa inhibitor edoxaban ameliorates hepatic ischemia-reperfusion injury via PAR-2-ERK 1/2 pathway.

Hepatic ischemia-reperfusion injury causes liver damage during surgery. In hepatic ischemia-reperfusion injury, the blood coagulation cascade is activated, causing microcirculatory incompetence and cellular injury. Coagulation factor Xa (FXa)- protease-activated receptor (PAR)-2 signaling activates inflammatory reactions and the cytoprotective effect of FXa inhibitor in several organs. However, no studies have elucidated the significance of FXa inhibition on hepatic ischemia-reperfusion injury. The present study elucidated the treatment effect of an FXa inhibitor, edoxaban, on hepatic ischemia-reperfusion injury, focusing on FXa-PAR-2 signaling. A 60 min hepatic partial-warm ischemia-reperfusion injury mouse model and a hypoxia-reoxygenation model of hepatic sinusoidal endothelial cells were used. Ischemia-reperfusion injury mice and hepatic sinusoidal endothelial cells were treated and pretreated, respectively with or without edoxaban. They were incubated during hypoxia/reoxygenation in vitro. Cell signaling was evaluated using the PAR-2 knockdown model. In ischemia-reperfusion injury mice, edoxaban treatment significantly attenuated fibrin deposition in the sinusoids and liver histological damage and resulted in both anti-inflammatory and antiapoptotic effects. Hepatic ischemia-reperfusion injury upregulated PAR-2 generation and enhanced extracellular signal-regulated kinase 1/2 (ERK 1/2) activation; however, edoxaban treatment reduced PAR-2 generation and suppressed ERK 1/2 activation in vivo. In the hypoxia/reoxygenation model of sinusoidal endothelial cells, hypoxia/reoxygenation stress increased FXa generation and induced cytotoxic effects. Edoxaban protected sinusoidal endothelial cells from hypoxia/reoxygenation stress and reduced ERK 1/2 activation. PAR-2 knockdown in the sinusoidal endothelial cells ameliorated hypoxia/reoxygenation stress-induced cytotoxicity and suppressed ERK 1/2 phosphorylation. Thus, edoxaban ameliorated hepatic ischemia-reperfusion injury in mice by protecting against micro-thrombosis in sinusoids and suppressing FXa-PAR-2-induced inflammation in the sinusoidal endothelial cells.

Tubulointerstitial nephritis with IgG4-positive plasma cell infiltration and tertiary lymphoid tissue in a patient with cryoglobulinemic vasculitis: a case report.

Tertiary lymphoid tissue (TLT) develops at sites of chronic immune stimulation, including infection, autoimmune disease, transplant rejection, and cancer. Recently, TLT has been focused on an indicator for poor renal prognosis in various kidney diseases. In cryoglobulinemic vasculitis (CV), specific glomerular and vascular lesions are seen; however, tubulointerstitial lesions are usually nonspecific. We herein report the case of a 74-year-old man with idiopathic CV with rare tubulointerstitial lesions, such as tubulointerstitial nephritis (TIN) with IgG4-positive plasma cell infiltration and TLT. To our knowledge, this is the first report identifying TLT in the kidney biopsy in a patient with CV. Glucocorticoid improved the renal outcome. The association between CV and TIN with TLT remains unknown.

Prognostic significance of preoperative to postoperative serum carcinoembryonic antigen ratio after lobectomy for lung adenocarcinoma.

INTRODUCTION: Lung adenocarcinoma with a preoperatively elevated serum carcinoembryonic antigen (CEA) value has a relatively poor postoperative prognosis. Although surgical resection generally results in a reduction in the CEA value, the significance of the change in the CEA value on the prognostic outcome remains unclear. METHODS: Our study included 133 patients who underwent lobectomy with curative intent for lung adenocarcinoma representing a preoperative CEA value > 5.0. Statistical analysis was performed using a receiver operating characteristic analysis and a stepwise Cox proportional hazards analysis. RESULTS: Both the postoperative CEA value and postoperative-to-preoperative CEA ratio (CEA ratio) significantly affected the survival. Although the CEA ratio was not predictive of the survival in patients with postoperative CEA ≤ 6.2 ng/ml (n = 105), it was predictive in the remaining patients with postoperative CEA > 6.2 ng/ml (n = 28). Patients with postoperative CEA > 6.2 ng/ml and a CEA ratio ≥ 0.39 (n = 7) showed the worst survival outcome. According to the multivariate analysis, the CEA ratio and postoperative nodal status were significant predictors of the survival in overall patients. CONCLUSION: The CEA ratio may be a useful prognostic marker in patients who undergo lobectomy for lung adenocarcinoma and show postoperative CEA > 6.2 ng/ml. A high CEA ratio may indicate the presence of a subclinical residual tumor, which may lead to the development of subsequent recurrence.

The harmful effects of overlooking acute bacterial prostatitis.

Prostatitis is a major urological disease affecting 25%-50% of men over their lifetime. However, prostatitis is often overlooked in nonurologic departments due to its sometimes indeterminate symptoms. In this review, we describe how to recognize and treat acute bacterial prostatitis, which manifests as a clinical problem in other departments as well as urology, to help prevent this disease from being overlooked. There are several possible negative effects of not recognizing acute bacterial prostatitis (ABP). First, initial treatment can fail. In the hyperacute phase, common antibiotics are often effective, but in rare cases, such antibiotics may not be effective. In addition, once ABP progresses to form a prostate abscess, potentially avoidable surgical interventions are often needed. A second issue is the transition to chronic prostatitis. If chronic bacterial prostatitis progresses, treatment requires long-term antibiotic administration and the response rate is not high. Some patients may have to deal with urinary tract infections for the rest of their lives. Finally, there is the problem of overlooking the underlying disease. ABP is rare in healthy adult men without underlying disease, including sexually transmitted diseases as well as benign prostatic hyperplasia, urinary stones, and malignant tumors, and may not be obvious. When examining patients with fever of unknown origin, it is necessary to exclude not only infectious diseases but also collagen diseases and malignant tumors. If there are any doubts, we recommend a rectal exam and consultation with a urologist.

The incorporation of extracellular vesicle markers varies among vesicles with distinct surface charges.

Extracellular vesicles (EVs) are important mediators of intercellular communication. However, the methods available for distinguishing the heterogeneity of secreted EVs and isolating and purifying them are limited. This study introduced a HiBiT-tag to detect various EV markers, including CD63, CD9, Epidermal Growth Factor Receptor (EGFR), Flotilin1, and Syndecan-1, and investigated whether these marker-containing vesicles were capable of binding to differently charged column carriers. Four column carriers, Diethylaminoethyl (DEAE), Capto Adhere, Blue and Heparin, showed affinity for CD63 containing EVs, but their elution patterns varied. Furthermore, we observed that the elution patterns of the EV markers differed among vesicles with distinct surface charges when a DEAE column was used. This suggests that the incorporation of EV markers varied between these vesicles. The markers showed different subcellular localizations, indicating that the site of vesicle formation may contribute to the production of vesicles with varying charges and marker incorporation. These findings may have implications for the development of methods to purify homogeneous EVs, which could be useful in EV-mediated drug delivery systems.

Entrectinib Response to ROS1-Fusion-Positive Non-Small-Cell Lung Cancer That Progressed on Crizotinib with Leptomeningeal Metastasis: A Case Report.

Introduction: C-ros oncogene 1 (ROS1) translocation is an oncogenic driver-mutation identified in 1-2% of non-small-cell lung cancer (NSCLC) cases. Although crizotinib, a tyrosine kinase inhibitor (TKI) against ALK/ROS1, is known to be effective against ROS1-fusion-positive NSCLC, such cases sometimes progress with brain metastases. The most frequently reported crizotinib-resistance mutation is ROS1 G2032R, and some studies have found that even newly developed ROS1 TKIs, such as entrectinib and lorlatinib, show a decreased efficacy against it. The optimal therapies for ROS1-fusion-positive NSCLC and how such cases can be sequenced have not yet been established. Case Presentation: We herein report a patient with ROS1-fusion-positive NSCLC diagnosed at 34 years old. Crizotinib was started at the diagnosis and switched after 25 months to cisplatin/pemetrexed/bevacizumab once the disease progressed with multiple brain metastases that were resistant to stereotactic radiation therapy. The cytotoxic chemotherapy stabilized the patient's condition for 17 months until he developed leptomeningeal metastasis (LM). He underwent lumboperitoneal shunting and whole-brain radiotherapy, followed by crizotinib re-administration. Despite crizotinib treatment, his neurological symptoms, such as double vision, headache, weakness in the legs, and walking difficulties, progressed. Eventually, subsequent entrectinib treatment was initiated, which resolved all of the symptoms mentioned above. Regrettably, liquid next-generation sequencing had failed to detect the resistance mechanism due to minimal ctDNA in this case. Conclusion: These findings imply that sequential entrectinib administration may be effective in patients with disease progression limited to central nervous system metastases during crizotinib administration.

Distinct motifs in the E protein are required for SARS-CoV-2 virus particle formation and lysosomal deacidification in host cells.

IMPORTANCE: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19), has caused a global public health crisis. The E protein, a structural protein found in this virus particle, is also known to be a viroporin. As such, it forms oligomeric ion channels or pores in the host cell membrane. However, the relationship between these two functions is poorly understood. In this study, we showed that the roles of E protein in virus particle and viroporin formation are distinct. This study contributes to the development of drugs that inhibit SARS-CoV-2 virus particle formation. Additionally, we designed a highly sensitive and high-throughput virus-like particle detection system using the HiBiT tag, which is a useful tool for studying the release of SARS-CoV-2.

Spleen volume is a predictor of posthepatectomy liver failure and short-term mortality for hepatocellular carcinoma.

BACKGROUND: The study aimed at retrospectively assessing the impact of spleen volume (SpV) on the development of posthepatectomy liver failure (PHLF) in patients who underwent hepatectomy for hepatocellular carcinoma (HCC). METHODS: 152 patients with primary HCC who underwent hepatectomy (sectionectomy or more) were classified into PHLF and non-PHLF groups, and then the relationship between PHLF and SpV was assessed. SpV (cm3) was obtained from preoperative CT and standardized based on the patient's body surface area (BSA, m2). RESULTS: PHLF was observed in 39 (26%) of the 152 cases. SpV/BSA was significantly higher in the PHLF group, and the postoperative 1-year survival rate was significantly worse in the PHLF group than that in the non-PHLF group (p = 0.044). Multivariable analysis revealed SpV/BSA as a significant independent risk factor for PHLF. Using the cut-off value (160 cm3/m2), the 152 cases were divided into small SpV and large SpV groups. The incidence of PHLF was significantly higher in the large SpV group (p = 0.002), the liver failure-related mortality rate was also significantly higher in the large SpV group (p = 0.007), and the 1-year survival rate was significantly worse in the large SpV group (p = 0.035). CONCLUSION: These results suggest SpV as a predictor of PHLF and short-term mortality in patients who underwent hepatectomy for HCC. Moreover, SpV measurement is a simple and potentially useful method for predicting PHLF in patients with HCC.

Urinary tract infections after retrograde pyelography and prophylactic antibiotics.

INTRODUCTION: Retrograde pyelography (RP) is performed for examination of upper urinary tract cancers and hydronephrosis. Although urinary tract infections (UTI) are known to be complicated by the examination, there are few reports on the frequency of occurrence and prophylactic antibiotics. METHODS: The incidence of UTI and febrile UTI (f-UTI) and patient background information were compared in 388 patients who underwent RP at our hospital from January 2018 to December 2022. We also examined the administration of pre-RP antibiotics. RESULTS: Of the 388 patients who underwent RP, 27 (6.9%) had UTI and 17 (4.4%) had f-UTI. Of the 27 UTI cases, 25 (92.6%) were pyelonephritis; 20 (74.0%) were hospitalized and 2 (7.4%) presented with septic shock and were managed in the intensive care unit. When comparing the background of patients with UTI, no significant differences were found in the present study, but when limited to the 17 cases of f-UTI, the presence of hydronephrosis before RP and not prescribing antibiotics before RP were associated with significantly higher incidence of f-UTI (p = 0.019, p = 0.036, respectively). Especially for patients without pyuria and bacteriuria before RP, prescribing antibiotics before RP resulted in 0 cases of f-UTI (p = 0.020). CONCLUSION: This retrospective study showed that the presence of hydronephrosis before RP and not prescribing prophylactic antibiotics before RP are risk factors for f-UTI.

Formation of DNA nanotubes increases uptake into fibroblasts via enhanced affinity for collagen.

DNA nanostructures are promising delivery carriers because of their flexible structural design and high biocompatibility. Selectivity in cellular uptake is an important factor in the development of DNA-nanostructure-based delivery carriers. In this study, DNA nanotubes were selected as the DNA structures, and their selectivity for cellular uptake and the mechanisms involved were investigated. Unlike DNA nanostructures such as polypod-like nanostructured DNA or DNA tetrahedrons, which are easily taken up by macrophages, the formation of DNA nanotubes increases uptake by fibroblasts and fibroblast-like cells. We focused on the collagen expressed in cells as a factor in this process, and found DNA nanotube formation increased the affinity for type I collagen compared with that of single-stranded DNA. Collagenase treatment removes collagen from fibroblasts and reduces the uptake of DNA nanotubes by fibroblasts. We directly observed DNA nanotube uptake by fibroblasts using transmission electron microscopy, whereby the nanotubes were distributed on the cell surface, folded, fragmented, and taken up by phagocytosis. In conclusion, we demonstrated a novel finding that DNA nanotubes are readily taken up by fibroblasts and myoblasts.

Extrapancreatic extension is a better adverse prognostic factor than tumor size in patients with localized pancreatic ductal adenocarcinoma treated with chemoradiotherapy - comparison of T category between the American Joint Committee on Cancer and Japan Pancreas Society.

BACKGROUND: T category classification for pancreatic ductal adenocarcinoma (PDAC) in the Classification of Pancreatic Cancer by the Japan Pancreas Society (JPS) is quite different from that of the American Joint Committee on Cancer (AJCC). The JPS classification focuses on extrapancreatic extension, while the AJCC focuses mainly on tumor size. This study aimed at identifying prognostic factors in PDAC patients undergoing chemoradiotherapy (CRT) by comparing the differences of T categories in these two classifications. METHODS: This retrospective study involved 344 PDAC patients who underwent CRT from 2005 to 2019 and their T-category variables were re-evaluated on computed tomography (CT) images. Disease-specific survival (DSS) was compared based on the JPS and AJCC T categories, while multivariate analysis was performed to identify prognostic factors. RESULTS: Based on the AJCC, 5-year DSS of T3 was better than those of T1 and T2 (57.1% vs. 47.7% and 37.4%). In multivariate analysis, performance status, CEA, the involvement of superior mesenteric vein and superior mesenteric artery, the JPS stage before CRT, and regimen of chemotherapy were identified as independent prognostic factors. CONCLUSIONS: In localized PDAC patients treated with chemoradiotherapy, extrapancreatic extension, as while as biological, conditional and therapeutic factors, is a better prognostic factor than tumor size.

Safety and efficacy of neoadjuvant chemotherapy based on our resectability criteria for locally advanced perihilar cholangiocarcinoma.

PURPOSE: Neoadjuvant chemotherapy (NAC) is not commonly used for perihilar cholangiocarcinoma (PHC). This study evaluated the safety and efficacy of NAC for PHC. METHODS: Ninety-one PHC patients without metastases were treated at our department. Patients were classified as resectable (R), borderline resectable (BR), or locally advanced unresectable (LA). Upfront surgery (US) was performed for R-PHC patients without regional lymph node metastases (LNM) or those unable to tolerate NAC. The NAC regimen comprised two courses of gemcitabine-based chemotherapy for advanced PHC: R-PHC with LNM, BR, and LA. RESULTS: US and NAC were performed on 32 and 59 patients, respectively. For US, 31 patients underwent curative intent surgery (upfront-CIS). NAC caused adverse effects in 10/59 (17%), allowed 36/59 (61%) to undergo curative intent surgery (NAC-CIS) without impairing liver function, and spared 23/59 (39%) from undergoing resection (NAC-UR). Overall survival was better in the upfront-CIS and NAC-CIS groups than in the NAC-UR group (MST: 74 vs 57 vs 17 months, p < 0.001). In 59 NAC patients, tumour size response occurred in 11/11 (100%) of R, 22/33 (66.7%) of BR, and 9/15 (60.0%) of LA patients. The un-resection rate was the highest in the LA group (27% [3/11] than in R, 30% [10/33] in BR, and 67% [10/15] in LA, p = 0.039). Multivariate analyses revealed that LA and age were independent risk factors for non-resection after NAC. CONCLUSION: was safe and contributed to improving survival in advanced PHC patients. R-PHC was responsive to NAC, but LA remains a risk factor for non-resection through NAC.

Growth and Migration Blocking Effect of Nanaomycin K, a Compound Produced by Streptomyces sp., on Prostate Cancer Cell Lines In Vitro and In Vivo.

Since castration-resistant prostate cancer (CRPC) acquires resistance to molecularly targeted drugs, discovering a class of drugs with different mechanisms of action is needed for more efficient treatment. In this study, we investigated the anti-tumor effects of nanaomycin K, derived from "Streptomyces rosa subsp. notoensis" OS-3966. The cell lines used were LNCaP (non-CRPC), PC-3 (CRPC), and TRAMP-C2 (CRPC). Experiments included cell proliferation analysis, wound healing analysis, and Western blotting. In addition, nanaomycin K was administered intratumorally to TRAMP-C2 carcinoma-bearing mice to assess effects on tumor growth. Furthermore, immuno-histochemistry staining was performed on excised tissues. Nanaomycin K suppressed cell proliferation in all cell lines (p < 0.001) and suppressed wound healing in TRAMP-C2 (p = 0.008). Nanaomycin K suppressed or showed a tendency to suppress the expression of N-cadherin, Vimentin, Slug, and Ras in all cell lines, and suppressed the phosphorylation of p38, SAPK/JNK, and Erk1/2 in LNCaP and TRAMP-C2. In vivo, nanaomycin K safely inhibited tumor growth (p = 0.001). In addition, suppression of phospho-Erk1/2 and increased expression of E-cadherin and cleaved-Caspase3 were observed in excised tumors. Nanaomycin K inhibits tumor growth and suppresses migration by inhibiting epithelial-mesenchymal transition in prostate cancer. Its mechanism of action is related to the inhibition of phosphorylation of the MAPK signaling pathway.