Background Regulatory T cells (Tregs) play important roles in the suppression of immune responses, including antitumor immune responses. C‐C chemokine receptor 4 (CCR4) is highly expressed on effector Tregs, and anti‐CCR4 antibody is attracting attention as a novel immunotherapeutic agent for solid tumors. This study aimed to evaluate the expression of CCR4‐positive Tregs (CCR4+Tregs) in prostate cancer and estimate the clinical potential of CCR4‐targeting therapy for prostate cancer. Methods A total of 15 radical prostatectomy (RP) specimens and 60 biopsy specimens from individuals diagnosed with prostate cancer were analyzed to evaluate the infiltration of CCR4+Tregs in prostate cancer. The relationships between the number of CCR4+Tregs and clinical parameters were investigated in RP and biopsy specimens. Moreover, the total number of Tregs, CCR4+Tregs, and T cells and the ratio of CCR4+Tregs to Tregs and T cells in biopsy specimens were compared between patients with poor prognosis who progressed to castration‐resistant prostate cancer (CRPC) within 12 months (n = 13) and those with good prognosis who were stable with hormone‐sensitive prostate cancer over 12 months (n = 47). Furthermore, biopsy specimens were divided into two groups: low and high CCR4+Treg expression groups and the prognosis was compared between them. Results There was a higher expression of CCR4+Tregs in RP specimens with a higher (≥8) Gleason score than in those with a lower (<8) Gleason score (P = .041). In biopsy specimens, 65.9% Tregs were positive for CCR4. The number of CCR4+Tregs positively correlated with clinical stage (P < .001) and Gleason score (P = .006). The total number of Tregs and CCR4+Tregs significantly increased in the poor prognosis group compared with that in the good prognosis group (P = .024 and .01, respectively). Furthermore, patients with lower CCR4+Treg expression levels showed a significantly longer time to progression to CRPC (not reached vs 27.3 months; P < .001) and median survival time (not reached vs 69.0 months; P = .014) than those with higher expression levels. Conclusions CCR4+Tregs are highly infiltrated in the prostate tissue of patients with poor prognosis with potential to progress to CRPC. Furthermore, the degree of infiltration of CCR4+Tregs is related to the prognosis of prostate cancer.

We previously showed that the Mycoplasma hyorhinis-encoded protein p37 can promote invasion of cancer cells in a dose-dependent manner, an effect that was blocked by monoclonal antibodies specific for p37. In this study, we further elucidated changes in growth, morphology and gene expression in prostate cancer cell lines when treated with exogenous p37 protein. Incubation with recombinant p37 caused significant nuclear enlargement, denoting active, anaplastic cells and increased the migratory potential of both PC-3 and DU145 cells. Microarray analysis of p37-treated and untreated cells identified eight gene expression clusters that could be broadly classified into three basic patterns. These were an increase in both cell lines, a decrease in either cell line or a cell line-specific differential trend. The most represented functional gene categories included cell cycle, signal transduction and metabolic factors. Taken together, these observations suggest that p37 potentiates the aggressiveness of prostate cancer and thus molecular events triggered by p37 maybe target for therapy.

Background: We determine the utility of serial urinary cytologies in patients presenting with microscopic hematuria who were evaluated with upper and lower urinary tract studies to rule out a malignancy.

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RESULTSEleven patients (22%) were positive for CgA; there was a significant difference in the time to recurrence ( P = 0.025) but no significant differences in cause-specific survival rate or survival rate after recurrence. In all, 21 patients (42%) were positive for HER-2; the cause-specific survival rate, time to recurrence and survival rate after recurrence were all significantly more favourable in the HER-2-negative group ( P = 0.008, 0.049 and 0.025, respectively). In the 49 patients for whom both factors could be determined, there was no significant correlation between CgA and HER-2 positivity. CONCLUSIONSNE cell differentiation of the primary tumour in patients with bone metastatic prostate cancer does not reflect the prognosis, whereas HER-2 overexpression is a prognostic factor for an unfavourable outcome. These results suggest that NE cell differentiation is not induced by HER-2.

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Docetaxel (DOC) is one of the most effective chemotherapeutic agents against castration-resistant prostate cancer (CRPC). Despite an impressive initial clinical response, the majority of patients eventually develop resistance to DOC. In tumor metabolism, where tumors preferentially utilize anaerobic metabolism, lactate dehydrogenase (LDH) serves an important role. LDH controls the conversion of pyruvate to lactate, with LDH-A, one of the predominant isoforms of LDH, controlling this metabolic process. In the present study, the role of LDH-A in drug resistance of human prostate cancer (PC) was examined by analyzing 4 PC cell lines, including castration-providing strains PC3, DU145, LNCaP and LN-CSS (which is a hormone refractory cell line established from LNCaP). Sodium oxamate (SO) was used as a specific LDH-A inhibitor. Changes in the expression level of LDH-A were analyzed by western blotting. Cell growth and survival were evaluated with a WST-1 assay. Cell cycle progression and apoptotic inducibility were evaluated by flow cytometry using propidium iodide and Annexin V staining. LDH expression was strongly associated with DOC sensitivity in PC cells. SO inhibited growth of PC cells, which was considered to be caused by the inhibition of LDH-A expression. Synergistic cytotoxicity was observed by combining DOC and SO in LN-CSS cells, but not in LNCaP cells. This combination treatment induced additive cytotoxic effects in PC-3 and DU145 cells, caused cell cycle arrest in G2-M phase and increased the number of cells in the sub-G1 phase of cell cycle in LN-CSS cells. SO promoted DOC induced apoptosis in LN-CSS cells, which was partially caused by the inhibition of DOC-induced increase in LDH-A expression. The results strongly indicated that LDH-A serves an important role in DOC resistance in advanced PC cells and inhibition of LDH-A expression promotes susceptibility to DOC, particularly in CRPC cells. The present study may provide valuable information for developing targeted therapies for CRPC in the future.

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