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Although docetaxel (DTX) confers significant survival benefits in patients with castration-resistant prostate cancer (CRPC), resistance to DTX inevitably occurs. Therefore, clarifying the mechanisms of DTX resistance may improve survival in patients with CRPC. Claspin plays a pivotal role in DNA replication stress and damage responses and is an essential regulator for the S-phase checkpoint. CLSPN is an oncogenic gene that contributes to tumor proliferation in several human solid tumors. However, the clinical significance of claspin in prostate cancer (PCa) has not been examined. The present study aimed to elucidate the role of claspin and its relationship with DTX resistance in PCa. We immunohistochemically analyzed the expression of claspin in 89 PCa cases, of which 31 (35%) were positive for claspin. Claspin-positive cases were associated with higher Gleason score, venous invasion, and perineural invasion. Kaplan–Meier analysis showed that high claspin expression was related to poor prostate-specific antigen (PSA) relapse-free prognosis. In a public database, high CLSPN expression was associated with poor PSA relapse-free prognosis, Gleason score, T stage, lymph node metastasis, CRPC, and metastatic PCa. Claspin knockdown by siRNA decreased cell proliferation, upregulated DTX sensitivity, and suppressed the expression of Akt, Erk1/2, and CHK1 phosphorylation in DU145 and PC3 cell lines. Furthermore, claspin expression was much more upregulated in DTX-resistant DU145 (DU145-DR) than in parental DU145 cells. Claspin knockdown significantly upregulated the sensitivity to DTX in DU145-DR cells. These results suggest that claspin plays an important role in PCa tumor progression and DTX resistance. [ABSTRACT FROM AUTHOR]

Aims: Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Genes expressed only in cancer tissue may be useful biomarkers for cancer diagnosis and therapeutics. The aims of the present study were to analyse regulator of calcineurin 2 (RCAN2) in a large number of GCs, and to investigate how these expression patterns correlate with clinicopathological parameters and various markers. Methods and results: An immunohistochemical analysis of RCAN2 in 207 GC tissue samples showed that 110 (53%) GCs were positive for RCAN2. RCAN2-positive GCs were more advanced in terms of TNM classification and tumour stage than RCAN2-negative GCs. Furthermore, RCAN2 was an independent prognostic classifier for GC patients. The cell growth and invasiveness of RCAN2 small interfering RNA (siRNA)-transfected GC cell lines were less than those of the negative control siRNA-transfected cell lines, whereas those of RCAN2-transfected cells were significantly increased as compared with those of empty vector-transfected cells. RCAN2 siRNA inhibits the phosphorylation of AKT and p44/p42 (ERK1/2). RCAN2 was colocalised with EGFR, nuclear b-catenin, MMP7, laminin-c2, VEGF-A, and VEGF-C. Conclusion: These results suggest that RCAN2 is involved in tumour progression and is an independent prognostic classifier in patients with GC. [ABSTRACT FROM AUTHOR]

Objectives Although chemotherapy for castration-resistant prostate cancer (CRPC) has been applied clinically in recent years, the effects are not sufficient. It is urgently necessary to develop novel therapeutics for CRPC. We previously generated Escherichia coli ampicillin secretion trap libraries of 2 prostate cancer (PCa) cell lines and normal prostate. By comparing the E. coli ampicillin secretion trap libraries of CRPC cell lines with those of androgen-sensitive PCa cell lines and normal prostate, we focused on the protein-tyrosine-phosphatase of regenerating liver 1 (PRL1) gene and analyzed its expression and biological function. Materials and methods The expression of PRL1 was examined by quantitative reverse transcription polymerase chain reaction and immunohistochemistry in clinical PCa samples. The effects of PRL1 on PCa cells were evaluated by cell growth, migration, and invasion assays. To investigate the effect of PRL1 on epidermal growth factor receptor (EGFR) signaling, PRL1 knockdown PC3 cells were examined by Western blot and immunohistochemical analyses. Results Quantitative reverse transcription polymerase chain reaction revealed that PRL1 was expressed much more highly in PCa than in nonneoplastic prostate samples. High expression of PRL1 detected by immunohistochemistry correlated with poor prognosis after prostatectomy and combined androgen blockade therapy. Functional analysis indicated that PRL1 stimulated cell growth, migration, and invasion in PCa cell lines. Expression EGFR and matrix metalloproteinase 9 was reduced by knockdown of PRL1 in the PC3 cell line. Conclusions PRL1 regulates expression of EGFR and modulates downstream targets. PRL1 has potential as a therapeutic target in PCa including CRPC. [ABSTRACT FROM AUTHOR]

Purpose: Upper tract urothelial carcinoma (UTUC) can be divided into renal pelvis tumor (RPT) and ureteral tumor (UT) based on the tumor origin. This study aimed to evaluate the efficacy of neoadjuvant chemotherapy with gemcitabine and cisplatin (NAC-GC) in terms of the pathological outcomes and oncological prognoses in patients with UTUC. We also compared its efficacy between RPT and UT. Materials and Methods: Patients who underwent radical nephroureterectomy for clinical T (cT)3N0M0 UTUC between 1999 and 2021 were included. Patients who underwent NAC-GC and those who did not were included in the NAC-GC and non-NAC-GC groups, respectively. Based on the tumor origin, we divided patients with UTUC into RPT and UT groups. Oncological prognosis was assessed using progression-free survival (PFS) and overall survival. Results: Of 44 patients, 20 (45.5%) and 24 (54.5%) patients were in the NAC-GC and non-NAC-GC groups, respectively. The NAC-GC group had significantly lower pathological T stage and negative lymphovascular invasion (LVI), and a better PFS (p < .05) compared to those in the non-NAC-GC group. Among patients with RPT, the NAC-GC group had significantly negative LVI and better PFS than the non-NAC-GC group (p < .05). In contrast, in patients with UT, the NAC-GC group had no significant difference in pathological outcomes, and no significant difference in oncological prognosis was observed between the NAC-GC and non-NAC-GC groups. Conclusion: NAC-GC improves both pathological outcomes and oncological prognosis in patients with cT3N0M0 UTUC. With regard to tumor location, RPT has better pathological outcomes and oncological prognoses than UT. [ABSTRACT FROM AUTHOR]

Bladder cancer, the majority of which is urothelial carcinoma (UC), is a common malignancy worldwide. Genes encoding transmembrane/secretory proteins expressed specifically in certain cancers may be ideal biomarkers for cancer diagnosis and may represent therapeutic targets. In the present study, the expression and function of the bone marrow stromal cell antigen 2 (BST2) gene was analyzed in UC. Reverse transcription‑quantitative polymerase chain reaction demonstrated that expression of BST2 in normal tissue samples was the highest in liver tissue. However, expression of BST2 in UC tissue samples was higher than in normal liver. Immunohistochemical analysis revealed weak or no staining of BST‑2 in non‑neoplastic mucosa, whereas UC tissue exhibited stronger and more extensive staining compared with non‑neoplastic mucosa. BST‑2 staining was observed mainly on UC cell membranes. In total, 28 (41%) of 69 UC cases were positive for BST‑2. UC cases positive for BST‑2 were more frequently T2/3/4 cases [so‑called muscle‑invasive bladder cancer (MIBC)] than Ta/is/1 cases (P=0.0001). However, Kaplan‑Meier analysis demonstrated no association between BST‑2 expression and survival. BST2 small interfering RNA (siRNA)‑transfected T24 cells exhibited significantly reduced cell growth relative to negative control siRNA‑transfected T24 cells. The levels of phosphorylated Akt and extracellular signal‑regulated kinase were lower in BST2 siRNA‑transfected T24 cells than in control cells. These results suggest the involvement of BST‑2 in the pathogenesis of UC. Since BST‑2 is expressed on the cell membrane, BST‑2 may be a good therapeutic target for MIBC. [ABSTRACT FROM AUTHOR]

An atomic bomb (A‑bomb) was dropped on Hiroshima on 6th August 1945. Although numerous studies have investigated cancer incidence and mortality among A‑bomb survivors, only a small number have addressed urological cancer in these survivors. The aim of the present study was to investigate the clinicopathological features of prostate cancer (PCa) in A‑bomb survivors. The clinicopathological features and prognosis of PCa were retrospectively reviewed in 212 survivors and 595 control patients between November 1996 and December 2010. The histopathological and clinical outcomes of surgical treatment of PCa were also evaluated in 69 survivors and 162 control patients. Despite the higher age at diagnosis compared with the control group (P=0.0031), survivors were more likely to have been diagnosed with PCa from a health check compared with the control group (P<0.0001). As a consequence, the survivors were found to exhibit metastasis significantly less frequently (199/212, 93.9%) compared with the control patients (521/595, 87.6%; P=0.0076). Prognosis in the two groups was examined, subsequent to a mean length of follow‑up of 44 months. Overall survival (OS) and PCa‑specific survival (CS) were similar between the two groups (OS, P=0.2196; CS, P=0.1017). A‑bomb exposure was not found to be an independent predictor for prognosis by multivariate analysis (OS, P=0.7800; CS, P=0.8688). The clinicopathological features of patients who underwent a prostatectomy were similar except for the diagnosis opportunity between the two groups. Progression‑free survival rates were similar between the two groups (P=0.5630). A‑bomb exposure was not a significant and independent predictor for worsening of progression‑free prognosis by multivariate analysis (P=0.3763). A‑bomb exposure does not appear to exert deleterious effects on the biological aggressiveness of PCa and the prognosis of patients with PCa. [ABSTRACT FROM AUTHOR]

Approximately 70 years have passed since the atomic bombs were dropped on Nagasaki and Hiroshima. To elucidate potential biomarkers and possible mechanisms of radiation-induced cancer, the expression of FKTN, which encodes fukutin protein and causes Fukuyama-type congenital muscular dystrophy, was analyzed in gastric cancer (GC) tissue samples from atomic bomb survivors. Expression of cluster of differentiation (CD) 10 was also evaluated, as it has previously been observed that positive fukutin expression was frequently noted in CD10-positive GC cases. In the first cohort from Hiroshima Red Cross Hospital and Atomic-Bomb Survivors Hospital (Hiroshima, Japan; n=92), 102 (53%) of the GC cases were positive for fukutin. Expression of fukutin was not associated with exposure status, but was associated with CD10 expression (P=0.0001). The second cohort was from Hiroshima University Hospital (Hiroshima, Japan; n=86), and these patients were also in the Life Span Study cohort, in which atomic bomb radiation doses were precisely estimated using the DS02 system. Expression of fukutin was detected in 58 (67%) of GC cases. GC cases positive for fukutin were observed more frequently in the low dose-exposed group than in the high dose-exposed group (P=0.0001). Further studies with a larger cohort, including precise radiation dose estimation, may aid in clarifying whether fukutin could serve as a potential biomarker to define radiation-induced GC in atomic-bomb survivors. [ABSTRACT FROM AUTHOR]

REG4, which encodes Reg IV protein, is a member of the calcium-dependent lectin superfamily and potent activator of the epidermal growth factor receptor/Akt/activator protein-1 signaling pathway. Several human cancers overexpress Reg IV, and Reg IV expression is associated with intestinal phenotype differentiation. However, regulation of REG4 transcription remains unclear. In the present study, we investigated whether CDX2 regulates Reg IV expression in gastric cancer (GC) cells. Expression of Reg IV and CDX2 was analyzed by Western blot and quantitative reverse transcription--polymerase chain reaction in 9 GC cell lines and 2 colon cancer cell lines. The function of the 5'-flanking region of the REG4 gene was characterized by luciferase assay. In 9 GC cell lines, endogenous Reg IV and CDX2 expression were well correlated. Using an estrogen receptor-regulated form of CDX2, rapid induction of Reg IV expression was observed in HT-29 cells. Reporter gene assays revealed an important role in transcription for consensus CDX2 DNA binding elements in the 5'-flanking region of the REG4 gene. Chromatin immunoprecipitation assays showed that CDX2 binds directly to the 5'-flanking region of REG4. These results indicate that CDX2 protein directly regulates Reg IV expression. [ABSTRACT FROM AUTHOR]