L-type amino acid transporter 1 (LAT1) is specifically expressed in many malignancies, contributes to the transport of essential amino acids, such as leucine, and regulates the mammalian target of rapamycin (mTOR) signaling pathway. We investigated the expression profile and functional role of LAT1 in prostate cancer using JPH203, a specific inhibitor of LAT1. LAT1 was highly expressed in castration-resistant prostate cancer (CRPC) cells, including C4-2 and PC-3 cells, but its expression level was low in castration-sensitive LNCaP cells. JPH203 significantly inhibited [14C] leucine uptake in CRPC cells but had no effect in LNCaP cells. JPH203 inhibited the proliferation, migration, and invasion of CRPC cells but not of LNCaP cells. In C4-2 cells, Cluster of differentiation (CD) 24 was identified by RNA sequencing as a novel downstream target of JPH203. CD24 was downregulated in a JPH203 concentration-dependent manner and suppressed activation of the Wnt/β-catenin signaling pathway. Furthermore, an in vivo study showed that JPH203 inhibited the proliferation of C4-2 cells in a castration environment. The results of this study indicate that JPH203 may exert its antitumor effect in CRPC cells via mTOR and CD24.

Background/Aim: The prognostic significance of androgen receptor amplification (AR amp) in cell-free DNA (cfDNA) was studied in Japanese patients with castration-resistant prostate cancer (CRPC). Patients and Methods: A total of 120 serum samples were obtained from 38 patients with CRPC. Serum cfDNA was purified and the AR copy number was determined. Factors associated with progressionfree survival (PFS) and overall survival (OS) were statistically investigated. Results: The number of patients administered enzalutamide (Enza)/abiraterone (Abi)/docetaxel (DTX) was 33/25/11, respectively. The median PSA was 16.5 ng/ml. Thirty patients (79%) had bone metastases and three patients (7.9%) had lung metastases. The median follow-up was 655 days. The median initial AR copy number was 1.27 (1.10-11.50); an AR copy number of 1.27 or higher was defined as an AR-amp. Regarding PFS, the presence of AR-amp, Gleason score (GS), and ALP were significant factors in univariate analysis. In multivariate analysis, AR amplification was an independent prognostic factor (hazard ratio=7.7, p=0.0035). For OS, PSA and AR-amp were significant factors. In multivariate analysis, AR-amp (hazard ratio=4.65, p=0.0188) was the only independent prognostic factor. Conclusion: AR-amp was associated with high nadir PSA and low iPSA/PSA ratio. ARamp was significantly associated with poor prognosis in Japanese patients with CRPC.

Non-muscle-invasive bladder carcinoma often occurs in older adults, who often also have urinary dysfunction. The residual urine volume is an important indicator of urinary dysfunction. However, the impact of the residual urine volume on intravesical recurrence remains unclear. In the present study, we analyzed the data of 372 patients at high or very high risk of cancer progression according to the Japanese Urological Association classification who had undergone transurethral resection of a bladder tumor. In univariate analysis, postoperative absence of intravesical Bacillus Calmette-Guérin (BCG) induction was an independent risk factor for intravesical recurrence (hazard ratio 1.94, absence versus presence, p = 0.0019). The incidence of intravesical recurrence did not significantly differ between the mild, intermediate, and severe residual urine groups in the total cohort. Among the BCG-treated cohort, the three groups showed similar trends. Among the non-BCG-treated cohort, although the patients with more than 100 ml of residual urine tended to have more intravesical recurrence than patients with a smaller residual urine volume, this difference did not reach statistical significance. BCG treatment is recommended for patients at high risk of bladder carcinoma. Patients with a large residual urine volume without BCG treatment may be at high risk of intravesical recurrence.

Abstract Objectives Renal cell carcinoma (RCC) is shown to have a tendency for late recurrence, occurring 5 or more years after curative surgery. Imaging diagnosis is required for follow‐up, and there is no definitive answer as to how long this should continue. Some patients discontinue follow‐up visits at their own discretion. How best to predict late recurrence and loss to follow‐up (LF) remains unclear. Patients and methods This study targeted patients diagnosed with non‐metastatic RCC who underwent either radical or partial nephrectomy at Chiba University Hospital between 1988 and 2021. Follow‐up for patients with RCC is typically lifelong. We used random survival forests (RSFs), a machine learning‐based survival analysis method, to predict late recurrence and LF. For verification of prediction accuracy, we applied the time‐dependent area under the receiver operating characteristic curve (t‐AUC). To analyse the risks of late recurrence and LF, SurvSHAP(t) and partial dependence plots were used. Results We analysed 1051 cases in this study. Median follow‐up was 58.5 (range: 0–376) months. The predictive accuracy of recurrence using RSF was t‐AUC 0.806, 0.761, 0.674 and 0.566 at 60, 120, 180 and 240 months postoperatively, respectively. The recurrence risk impact showed a time‐dependent increase up to approximately 50 months postoperatively. Beyond 50 months, there were no distinct risk factors characteristic of late recurrence. The predictive accuracy of LF using RSF was t‐AUC 0.542, 0.699, 0.685, 0.628 and 0.674 at 60, 120, 180, 240 and 300 months postoperatively, respectively. The risk of LF increased with advancing age beyond 70 years. Conclusion It is difficult to identify factors that predict late recurrence. For long‐term follow‐up observation, it is essential to pay particular attention to patients with RCC aged 70 years and above. Establishing frameworks to facilitate collaboration with local hospitals near patients' residences and providing care within the community is necessary.

The 4F2 cell-surface antigen heavy chain (4F2hc) forms a heterodimeric complex with L-type amino acid transporter 1 (LAT1) and transports large neutral essential amino acids. However, in contrast to the traditional role of LAT1 in various cancers, the role of 4F2hc has largely remained unknown. The role of 4F2hc in prostate cancer was studied. Treatment of C4-2 cells with si4F2hc was found to suppress cellular growth, migratory and invasive abilities, with this effect occurring through the cell cycle, with a significant decrease in S phase and a significant increase in G0/G1 phase, suggesting cell cycle arrest. In addition, it was proven by RNA seq that the key to 4F2hc’s impact on cancer is SKP2. si4F2hc upregulates the protein expression of cyclin-dependent kinase inhibitors (P21cip1, P27kip1) through the downstream target SKP2. Furthermore, the expression of 4F2hc and LAT1 in prostate cancer cells suggests the importance of 4F2hc. Multivariate analysis showed that high 4F2hc expression was an independent prognostic factor for progression-free survival (HR 11.54, p = 0.0357). High 4F2hc was related to the clinical tumour stage (p = 0.0255) and Gleason score (p = 0.0035). Collectively, 4F2hc contributed significantly to prostate cancer (PC) progression. 4F2hc may be a novel marker and therapeutic target in PC.

L‐type amino acid transporter 3 (LAT3, SLC43A1 ) is abundantly expressed in prostate cancer (PC) and is thought to play an essential role in PC progression through the cellular uptake of essential amino acids. Here, we analyzed the expression, function, and downstream target of LAT3 in PC. LAT3 was highly expressed in PC cells expressing androgen receptor (AR), and its expression was increased by dihydrotestosterone treatment and decreased by bicalutamide treatment. In chromatin immunoprecipitation sequencing of AR, binding of AR to the SLC43A1 region was increased by dihydrotestosterone stimulation. Knockdown of LAT3 inhibited cell proliferation, migration, and invasion, and the phosphorylation of p70S6K and 4EBP‐1. Separase ( ESPL1 ) was identified as a downstream target of LAT3 by RNA sequencing analysis. In addition, immunostaining of prostatectomy specimens was performed. In the multivariate analysis, high expression of LAT3 was an independent prognostic factor for recurrence‐free survival (hazard ratio: 3.24; P = .0018). High LAT3 expression was correlated with the pathological T stage and a high International Society of Urological Pathology grade. In summary, our results suggest that LAT3 plays an important role in the progression of PC.

The 4F2 cell-surface antigen heavy chain (4F2hc) forms a heterodimeric complex with L-type amino acid transporter 1 (LAT1) and transports large neutral essential amino acids. However, in contrast to the traditional role of LAT1 in various cancers, the role of 4F2hc has largely remained unknown. The role of 4F2hc in prostate cancer was studied. Treatment of C4-2 cells with si4F2hc was found suppress cellular growth and migratory and invasive abilities, with this effect occurring through the cell cycle, with a significant decrease in S phase and a significant increase in G0/G1 phase, suggesting cell cycle arrest. In addition, it was proven by RNA seq that the key to 4F2hc’s impact on cancer is SKP2. The expression of 4F2hc and LAT1 in prostate cancer cells suggests the importance of 4F2hc. Furthermore, si4F2hc, through the downstream target SKP2, upregulates the protein expression of cyclin-dependent kinase inhibitors (P21cip1, P27kip1). Multivariate analysis showed that high 4F2hc expression was an independent prognostic factor for progression-free survival (HR 11.54, p=0.0357). High 4F2hc was related to the clinical tumour stage (p=0.0255) and Gleason score (p=0.0035). Collectively, 4F2hc contributed significantly to prostate cancer (PC) progression. 4F2hc may be a novel marker and therapeutic target in PC.

L-type amino acid transporter 1 (LAT1) plays a role in transporting essential amino acids including leucine, which regulates the mTOR signaling pathway. Here, we studied the expression profile and functional role of LAT1 in bladder cancer. Furthermore, the pharmacological activity of JPH203, a specific inhibitor of LAT1, was studied in bladder cancer. LAT1 expression in bladder cancer cells was higher than that in normal cells. SiLAT1 and JPH203 suppressed cell proliferative and migratory and invasive abilities in bladder cancer cells. JPH203 inhibited leucine uptake by > 90%. RNA-seq analysis identified insulin-like growth factor-binding protein-5 (IGFBP-5) as a downstream target of JPH203. JPH203 inhibited phosphorylation of MAPK / Erk, AKT, p70S6K and 4EBP-1. Multivariate analysis revealed that high LAT1 expression was found as an independent prognostic factor for overall survival (HR3.46 P = 0.0204). Patients with high LAT1 and IGFBP-5 expression had significantly shorter overall survival periods than those with low expression (P = 0.0005). High LAT1 was related to the high Grade, pathological T stage, LDH, and NLR. Collectively, LAT1 significantly contributed to bladder cancer progression. Targeting LAT1 by JPH203 may represent a novel therapeutic option in bladder cancer treatment.

You have accessJournal of UrologyBladder Cancer: Basic Research & Pathophysiology I (MP51)1 Apr 2019MP51-04 AN L-TYPE AMINO ACID TRANSPORTER 1 INHIBITOR: JPH203 SUPPRESSES BLADDER CANCER GROWTH AND INVASION VIA IGFBP-5 Maihulan Maimaiti*, Shinichi Sakamoto, Masahiro Sugiura, Minhui Xu, Yasutaka Yamada, Kosuke Higuchi, Keisuke Ando, Nobushige Takeshita, Akira Komiya, Yuzuru Ikehara, Yosikatsu Kanai, Naohiko Anzai, and Tomohiko Ichikawa Maihulan Maimaiti*Maihulan Maimaiti* More articles by this author , Shinichi SakamotoShinichi Sakamoto More articles by this author , Masahiro SugiuraMasahiro Sugiura More articles by this author , Minhui XuMinhui Xu More articles by this author , Yasutaka YamadaYasutaka Yamada More articles by this author , Kosuke HiguchiKosuke Higuchi More articles by this author , Keisuke AndoKeisuke Ando More articles by this author , Nobushige TakeshitaNobushige Takeshita More articles by this author , Akira KomiyaAkira Komiya More articles by this author , Yuzuru IkeharaYuzuru Ikehara More articles by this author , Yosikatsu KanaiYosikatsu Kanai More articles by this author , Naohiko AnzaiNaohiko Anzai More articles by this author , and Tomohiko IchikawaTomohiko Ichikawa More articles by this author View All Author Informationhttps://doi.org/10.1097/01.JU.0000556455.14355.d4AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVES: Cancer cells take up massive amounts of amino acids for survival. L-type amino acid transporter 1(LAT1) transports essential amino acids, including leucine, which triggers the downstream m-TOR pathway. In collaboration, we have created JPH203, a novel tyrosine analog, inhibits LAT1 selectively without affecting other types of the transporter, which went through Phase I clinical trial in Japan. Here we study examined 1) the association between bladder cancer and LAT1 expression, and 2) study the role of JPH203 in METHODS: Gene expression was compared by Real-Time PCR and expression of related proteins was examined by Western blotting. SiRNA was used for knocking down the target gene. triggers experiment of bladder cancer cell line was performed using LAT1 inhibitor JPH203. Genes related to LAT1 were analyzed using RNA-Seq. 68 total cystectomy patient's data was used to study the clinical relevance. Univariate and multivariate Cox hazard proportional models and the Kaplan-Meier method were used for the statistical analysis. RESULTS: LAT1 was highly expressed in 5637 cells and T24 cells. LAT1 knockdown and JPH203 (10µM and 20µM) suppressed cell proliferative, invasive and migratory ability. JPH203 inhibited phosphorylation of MAPK / Erk, AKT, p70S6K and 4EBP-1. JPH 203 inhibits C14 leucine uptake while increasing apoptosis. IGFBP-5 was identified as a gene that significantly changed (0.35 times) by SiLAT1 by RNA-Seq analysis. SiIGFBP-5 suppressed the cell proliferation in two bladder cancer cell lines (p<0.05). In proportional hazard analysis, the LAT1 expression (HR5.60 p=0.0142), grade (HR4.78 p=0.0194) and smoke (HR6.04 p=0.0036) are the independent predictors of overall survival in bladder cancer patients who received total cystectomy. On Kaplan-Meier analysis, patients with high expression of LAT1+IGBP-5 showed significantly poor survival compared to the low expression of LAT1+IGFBP-5 (p=0.0013). CONCLUSIONS: LAT1 potentially contributed to the progression of bladder cancer cells through IGFBP-5 related pathway. Since JPH 203 underwent the phase I clinical trial in solid cancer patients, the clinical benefit of JPH203 in bladder cancer patient is awaited to be investigated. Source of Funding: None Chiba, Japan; Osaka, Japan; Chiba, Japan© 2019 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 201Issue Supplement 4April 2019Page: e724-e725 Advertisement Copyright & Permissions© 2019 by American Urological Association Education and Research, Inc.MetricsAuthor Information Maihulan Maimaiti* More articles by this author Shinichi Sakamoto More articles by this author Masahiro Sugiura More articles by this author Minhui Xu More articles by this author Yasutaka Yamada More articles by this author Kosuke Higuchi More articles by this author Keisuke Ando More articles by this author Nobushige Takeshita More articles by this author Akira Komiya More articles by this author Yuzuru Ikehara More articles by this author Yosikatsu Kanai More articles by this author Naohiko Anzai More articles by this author Tomohiko Ichikawa More articles by this author Expand All Advertisement PDF downloadLoading ...

314 Background: We study the prognostic ability of androgen receptor amplification (AR amp) from cf DNA in Japanese castration-resistant prostate cancer (CRPC) patients. Methods: Multiple sets of serums were obtained from 38 castration-resistant prostate cancer patient at Chiba University hospital. Serum cfDNA was purified using a cobas cfDNA Sample Preparation Kit. AR copy number was measured using the QX100 Droplet Digital PCR System. Factors associated with progression-free survival (PFS) and Overall Survival (OS) were statistically studied. Results: The number of patients received Enzalutamide (Enza)/Abiraterone (Abi)/Docetaxel (Doc) were 33/25/11. Regarding PFS, the presence of AR amplification, Bone Scan Index (BSI), PSA was significant factors on univariate analysis. On multivariate analysis, AR amplification was an independent prognostic factor (HR. 8.9, p=0.003). Regarding OS, PSA and AR amp was significant factors. On multivariate analysis, AR amp (HR 4.2, p=0.028) was an independent prognostic factor. AR amp was related to the young age, high bone metastasis, high PSA, while no association was identified related the visceral metastasis. Overall, the presence of AR amp was negatively related to the initial ADT periods (r=-0.28). In contrary, among primary resistance cases (initial treatment periods <1 year), AR amp positively related to the treatment periods (r=0.31). Higher nadir testosterone (>15 ng/dL) was related to the higher AR amp (p=0.0169). AR amp was related to the treatment resistance in Enza (p=0.0216), while no relation was observed in Abi or Doc. Conclusions: AR amp significantly correlated with the poor prognosis. Higher serum testosterone level may predict the presence of AR amp in cf DNA. [Table: see text]

BACKGROUND:The role of testosterone as a prognostic factor for castration-resistant prostate cancer treated with docetaxel in Japan was investigated. METHODS:A total of 164 patients with castration-resistant prostate cancer who received docetaxel treatment at Chiba University Hospital and an affiliated hospital were retrospectively analyzed. Testosterone and other clinical factors at the start of docetaxel treatment were evaluated with respect to overall survival and progression-free survival. RESULTS:Of the 164 patients, 69 had high-volume tumors. The median prostatic-specific antigen was 27.0 ng/mL. The median testosterone was 13.0 ng/dL. The rates of bone and visceral metastases were 80.1% and 8.8%, respectively. For progression-free survival, testosterone ≥13 ng/dL was an independent prognostic factor only on univariate analysis (hazard ratio, 1.81; P = .0108). For overall survival, testosterone ≥ 1.3 ng/dL (hazard ratio, 3.37; P < .0001), high volume (hazard ratio, 3.06; P = .0009), and prostate-specific antigen ≥ 27.0 ng/mL (hazard ratio, 2.75; P = .0013) were independent prognostic factors on multivariate analysis. When assessing related clinical factors, higher serum testosterone was associated with visceral metastasis, high volume, and prostate-specific antigen. Based on three prognostic factors (testosterone, high volume, prostate-specific antigen), a risk classification was developed. The high-risk group (3 risk factors) showed a significantly shorter overall survival compared to the moderate-risk (2 risk factors) and low-risk (0-1 risk factor) groups (P < .0001). CONCLUSIONS:The present study identified higher serum testosterone (≥13 ng/dL) as a significant prognostic factor in castration-resistant prostate cancer patients treated with docetaxel therapy.

Large neutral amino acid transporter 1 (LAT1, SLC7A5) is abundantly expressed in various types of cancer, and it has been thought to assist cancer progression through its activity for uptake of neutral amino acids. However, the roles of LAT1 in renal cell carcinoma (RCC) prognosis and treatment remain uncharacterized. Therefore, we first retrospectively examined the LAT1 expression profile and its associations with clinical factors in RCC tissues (n = 92). The results of immunohistochemistry showed that most of the tissues examined (92%) had cancer-associated LAT1 expression. Furthermore, the overall survival (OS) and progression-free survival (PFS) were shorter in patients with high LAT1 expression levels than in those with low LAT1 expression levels (P = 0.018 and 0.014, respectively), and these associations were further strengthened by the results of univariate and multivariate analyses. Next, we tested the effects of JPH203, which is a selective LAT1 inhibitor, on RCC-derived Caki-1 and ACHN cells. It was found that JPH203 inhibited the growth of these cell types in a dose-dependent manner. Moreover, JPH203 clearly suppressed their migration and invasion activities. Thus, our results show that LAT1 has a great potential to become not only a prognosis biomarker but also a therapeutic target in RCC clinical settings.

Prostate cancer is generally known as cancer with a good prognosis, and even in metastatic cases, the 10-year survival rate in Japan is around 38%. Since gene mutations constantly change over a relatively long course of treatment, the clinical utility of Liquid Biopsy, which can evaluate mutations from cancer cells in the blood, is attracting clinical attention. As a result of analysis using a next-generation sequencer, the most frequent mutation is androgen receptor amplification (AR Amp), followed by P53 mutation and PTEN mutation.

PURPOSE:We examined the clinical significance of long-term serum testosterone monitoring to predict the prognosis of patients with prostate cancer treated with combined androgen blockade. MATERIALS AND METHODS:We retrospectively analyzed the records of 225 patients who underwent combined androgen blockade as first line therapy for prostate cancer. The prognostic values of testosterone and other clinical factors were evaluated with respect to prostate specific antigen progression-free and overall survival. RESULTS:Median patient age was 73.0 years, median prostate specific antigen was 42.6 ng/ml and median followup was 45.8 months. No variable associated with testosterone was predictive of progression-free survival. With regard to overall survival on univariate analysis nadir testosterone less than 16 ng/dl (p = 0.0190), less than 20 ng/dl (p = 0.0020) and less than 32 ng/dl (p = 0.0146) were significant together with other clinical factors. In contrast, nadir testosterone less than 8 and less than 12 ng/dl were not significant. Multivariate analysis showed that nadir testosterone less than 20 ng/dl was the significant prognostic factor (p = 0.0048). In addition, time to nadir testosterone was about 1 year (11.3 months). Patients were divided into rapid and slow types based on time to testosterone less than 20 ng/dl before and after 6 months, respectively. No significant difference in overall survival was observed between the 2 types. The current results suggest that the critical factor for prognosis was not a rapid decrease but whether nadir testosterone achieved a level of less than 20 ng/dl. CONCLUSIONS:Nadir testosterone 20 ng/dl was the most significant cutoff level for overall survival in Japanese patients with prostate cancer treated with combined androgen blockade.