Takashi Dejima

Notch-Hes1 pathway is required for the development of IL-17–producing γδ T cells

Unlike conventional T cells, which are exported from the thymus as naive cells and acquire effector functions upon antigen encounter in the periphery, a subset of γδ T cells differentiates into effectors that produce IL-17 within the fetal thymus. We demonstrate here that intrathymic development of the naturally occurring IL-17-producing γδ T cells is independent of STAT3 and partly dependent on RORγt. Comparative gene-expression analysis identified Hes1, one of the basic helix-loop-helix proteins involved in Notch signaling, as a factor specifically expressed in IL-17-producing γδ T cells. Hes1 is critically involved in the development of IL-17-producing γδ T cells, as evidenced by their severe decrease in the thymi of Hes1-deficient fetal mice. Delta-like 4 (Dll4)-expressing stromal cells support the development of IL-17-producing γδ T cells in vitro. In addition, conditional Hes1 ablation in peripheral γδ T cells decreases their IL-17 production but not their IFN-γ production. These results reveal a unique differentiation pathway of IL-17-producing γδ T cells.

IL-17 production by γδ T cells is important for the antitumor effect of Mycobacterium bovis bacillus Calmette-Guérin treatment against bladder cancer.

Intravesical inoculation of Mycobacterium bovis bacillus Calmette‐Guérin (BCG) has been used for the treatment of bladder cancer. Recent studies implied the requirement of neutrophil infiltration for the antitumor effect. In this study, we found that IL‐17 was produced in the bladder after BCG treatment, preceding the infiltration of neutrophils. Neutrophils in the bladder after BCG treatment were reduced in IL‐17‐deficient mice, in which BCG‐induced antitumor effect against intravesically inoculated bladder cancer was abolished. Notably, the level of IL‐17 production and the number of neutrophils in BCG‐treated bladder was reduced in γδ T‐cell‐deficient mice but not in CD4‐depleted mice. Survival of bladder cancer‐inoculated γδ T‐cell‐deficient mice was not improved by BCG treatment. These results suggest that IL‐17‐producing γδ T cells play a key role in the BCG‐induced recruitment of neutrophils to the bladder, which is essential for the antitumor activity against bladder cancer.

Protective Role of Naturally Occurring Interleukin-17A-Producing γδ T Cells in the Lung at the Early Stage of Systemic Candidiasis in Mice

ABSTRACT Interleukin-17A (IL-17A)-producing γδ T cells differentiate in the fetal thymus and reside in the peripheral tissues, such as the lungs of naïve adult mice. We show here that naturally occurring γδ T cells play a protective role in the lung at a very early stage after systemic infection with Candida albicans. Selective depletion of neutrophils by in vivo administration of anti-Ly6G monoclonal antibody (MAb) impaired fungal clearance more prominently in the lung than in the kidney 24 h after intravenous infection with C. albicans. Rapid and transient production of IL-23 was detected in the lung at 12 h, preceding IL-17A production and the influx of neutrophils, which reached a peak at 24 h after infection. IL-17A knockout (KO) mice showed reduced infiltration of neutrophils concurrently with impaired fungal clearance in the lung after infection. The major source of IL-17A was the γδ T cell population in the lung, and Cδ KO mice showed little IL-17A production and reduced neutrophil infiltration after infection. Early IL-23 production in a TLR2/MyD88-dependent manner and IL-23-triggered tyrosine kinase 2 (Tyk2) signaling were essential for IL-17A production by γδ T cells. Thus, our study demonstrated a novel role of naturally occurring IL-17A-producing γδ T cells in the first line of host defense against C. albicans infection.

Interaction between docetaxel resistance and castration resistance in prostate cancer: implications of Twist1, YB-1, and androgen receptor.

Taxanes, including docetaxel, are currently the only cytotoxic chemotherapeutic agents proven to confer survival benefit in patients with castration‐resistant prostate cancer (CRPC). However, the merits of taxanes remain modest, and efforts are needed to improve their therapeutic efficacy.

Suppressed Recurrent Bladder Cancer after Androgen Suppression with Androgen Deprivation Therapy or 5α-Reductase Inhibitor

Purpose: We determined whether intravesical recurrence is affected by inhibition of androgen signaling among men with nonmuscle invasive bladder cancer. Materials and Methods: We examined the intravesical recurrence rate among men treated with or without androgen suppression therapy by androgen deprivation therapy for prostate cancer or 5&agr;‐reductase inhibitor dutasteride for benign prostatic hyperplasia. Results: We studied 228 men, including 32 with and 196 without androgen suppression therapy. During a median followup of 3.6 and 3.0 years intravesical recurrence developed in 4 (12.5%) and 59 men (30.1%) with and without androgen suppression therapy, respectively. On multivariate analysis multiple tumors (HR 1.82, p = 0.027), a large tumor (HR 2.13, p = 0.043) and ever smoking (HR 2.45, p = 0.020) as well as the presence of androgen suppression therapy (HR 0.36, p = 0.024) were independent risk factors for intravesical recurrence. Notably, tumor progressed to muscle invasive bladder cancer in 6 men (3.1%) without androgen suppression therapy. No man with androgen suppression therapy progressed to muscle invasive bladder cancer. Conclusions: Our study suggests the possibility of androgen suppression therapy as prophylaxis for intravesical recurrence of bladder cancer. Further explorations are warranted of the prophylactic effect of androgen suppression therapy on bladder cancer pathogenesis.

The prognostic impact of serum testosterone during androgen-deprivation therapy in patients with metastatic prostate cancer and the SRD5A2 polymorphism

Background:Although testosterone suppression during androgen-deprivation therapy (ADT) and obesity have been reported to affect ADT efficacy, there are few comprehensive analyses on the impact on ADT outcome. Recently, we demonstrated that the SRD5A2 polymorphism was associated with metastatic prostate cancer prognosis. Therefore, in this study, we investigated the relationship between ADT serum testosterone levels or body mass index (BMI) and the prognosis among men treated with primary ADT for metastatic prostate cancer. In addition, we examined the association of serum testosterone levels during ADT with the SRD5A2 polymorphism.Methods:This study included 96 Japanese patients with metastatic prostate cancer. The relationship between clinicopathological parameters, including serum testosterone levels during ADT and BMI, and progression-free survival, overall survival and survival from progression following primary ADT treatment for metastatic prostate cancer was examined. Additionally, the association between the SRD5A2 gene polymorphism (rs523349) and serum testosterone levels during ADT was examined in 86 cases.Results:Among clinicopathological parameters, the lowest quartile of serum testosterone levels during ADT was a significant predictor of better overall survival as well as survival from castration resistance. However, BMI was not associated with prognosis. The CC allele in the SRD5A2 gene (rs523349), encoding the less active 5α-reductase, was associated with lower serum testosterone levels during ADT.Conclusions:Taken together, these findings revealed a dramatic suppression of serum testosterone by ADT was associated with better survival among men with metastatic prostate cancer that have undergone primary ADT, which may be affected by the SRD5A2 gene polymorphism.

PMA induces androgen receptor downregulation and cellular apoptosis in prostate cancer cells.

Phorbol 12-myristate 13-acetate (PMA) induces cellular apoptosis in prostate cancer cells, the growth of which is governed by androgen/androgen receptor (AR) signaling, but the mechanism by which PMA exerts this effect remains unknown. Therefore, in this study, we investigated the mechanistic action of PMA in prostate cancer cells with regard to AR. We showed that PMA decreased E2F1 as well as AR expression in androgen-dependent prostate cancer LNCaP cells. Furthermore, PMA activated JNK and p53 signaling, resulting in the induction of cellular apoptosis. In LNCaP cells, androgen deprivation and a novel anti-androgen enzalutamide (MDV3100) augmented cellular apoptosis induced by PMA. Moreover, castration-resistant prostate cancer (CRPC) C4-2 cells were more sensitive to PMA compared with LNCaP cells and were sensitized to PMA by enzalutamide. Finally, the expression of PKC, E2F1, and AR was diminished in PMA-resistant cells, indicating that the gain of independence from PKC, E2F1, and AR functions leads to PMA resistance. In conclusion, PMA exerted its anti-cancer effects via the activation of pro-apoptotic JNK/p53 and inhibition of pro-proliferative E2F1/AR in prostate cancer cells including CRPC cells. The therapeutic effects of PMA were augmented by androgen deletion and enzalutamide in androgen-dependent prostate cancer cells, as well as by enzalutamide in castration-resistant cells. Taken together, PMA derivatives may be promising therapeutic agents for treating prostate cancer patients including CRPC patients.

The Differential Impact of Body Mass Index and the Feature of Metabolic Syndrome on Oncological Outcomes Following Different Surgical Procedures in Japanese Men with Prostate Cancer

AbstractPurposeThis study aimed to examine the differential impact of body mass index and the feature of metabolic syndrome (MetS; obesity, hypertension, diabetes mellitus, and dyslipidemia) on biochemical recurrence (BCR) following radical prostatectomy (RP) treatment for prostate cancer using different surgical procedures.MethodsThis study included 283 Japanese patients with clinically localized prostate cancer who were treated with RP between 2008 and 2012. The prognostic significance of overweight and the feature of MetS were analyzed according to surgical procedures. ResultsBCR occurred in 68/283 (24.0%) men. Overweight and the feature of MetS were predictors of BCR in patients who had undergone open RP (ORP), but not in those treated with laparoscopic surgery. Multivariate analyses incorporating preoperative and postoperative risk factors revealed that overweight and the feature of MetS were independent BCR risk factors when treated with ORP.ConclusionsIn Japanese men, overweight and the feature of MetS were associated with worse outcomes following RP, particularly ORP, compared with those following laparoscopic surgery. These results suggest that laparoscopic surgery can overcome the surgical challenges associated with abdominal obesity.This study aimed to examine the differential impact of body mass index and the feature of metabolic syndrome (MetS; obesity, hypertension, diabetes mellitus, and dyslipidemia) on biochemical recurrence (BCR) following radical prostatectomy (RP) treatment for prostate cancer using different surgical procedures. This study included 283 Japanese patients with clinically localized prostate cancer who were treated with RP between 2008 and 2012. The prognostic significance of overweight and the feature of MetS were analyzed according to surgical procedures. BCR occurred in 68/283 (24.0%) men. Overweight and the feature of MetS were predictors of BCR in patients who had undergone open RP (ORP), but not in those treated with laparoscopic surgery. Multivariate analyses incorporating preoperative and postoperative risk factors revealed that overweight and the feature of MetS were independent BCR risk factors when treated with ORP. In Japanese men, overweight and the feature of MetS were associated with worse outcomes following RP, particularly ORP, compared with those following laparoscopic surgery. These results suggest that laparoscopic surgery can overcome the surgical challenges associated with abdominal obesity.

Protein kinase C regulates Twist1 expression via NF-κB in prostate cancer

The progression of prostate cancer to metastatic and castration-resistant disease represents a critical step. We previously showed that protein kinase C (PKC) activation followed by Twist1 and androgen receptor (AR) induction played a critical role in castration resistance, but the precise molecular mechanism remains unknown. This study aimed to elucidate the relevant molecular mechanism, focusing on NF-κB transcription factor. We examined the activity of NF-κB after PKC inhibition, and the expression of Twist1 and AR after inhibition of NF-κB in human prostate cancer cells. We also investigated the status of PKC/NF-κB after inhibition of AR signaling in cells resistant to hormonal therapy. As a result, inhibition of PKC signaling using knockdown and small-molecule inhibition of PKC suppressed RelA activity, while blocking NF-κB suppressed Twist1 and AR expression. Conversely, inhibition of AR signaling by androgen depletion and the novel antiandrogen enzalutamide induced PKC and RelA activation, resulting in Twist1/AR induction at the transcript level. Moreover, inhibition of NF-κB signaling prevented enzalutamide-induced Twist1 and AR induction. Finally, NF-κB was activated in both castration-resistant and enzalutamide-resistant cells. In conclusion, NF-κB signaling was responsible for Twist1 upregulation by PKC in response to AR inhibition, resulting in aberrant activation of AR. NF-κB signaling thus appears to play a critical role in promoting both castration resistance and enzalutamide resistance in PKC/Twist1 signaling in prostate cancer.

Antitumor activity of recombinant Bacille Calmette-Guérin secreting interleukin-15-Ag85B fusion protein against bladder cancer

Mycobacterium bovis Bacillus Calmette-Guérin (BCG) is used for the treatment of bladder cancer. The recruitment of neutrophlis to the bladder after BCG instillation exerts anti-tumor activity against bladder tumor. We have recently demonstrated that interleukin (IL)-17A produced by γδ T cells played a role in the recruitment of neutrophlis to the bladder after BCG instillation. IL-15 is known to play an important role in neutrophil migration during inflammation. We previously constructed a recombinant BCG strain expressing the fusion protein of IL-15 and Ag85B (BCG-IL-15) for prevention of Mycobacterium tuberculosis infection. Here we compared the efficacy of the BCG-IL-15 in protection against bladder cancer with that of rBCG-Ag85B (BCG). Six-week-old female C57BL/6 mice were inoculated with MB49 bladder tumor cells in the bladder and subsequently intravesically inoculated with BCG or BCG-IL-15. BCG-IL-15 treatment significantly prolonged survival of mice inoculated with bladder cancer cells compared with BCG treatment. Infiltration of neutrophils was significantly elevated in BCGB-IL-15 treated mice accompanied by increased chemokines (MIP-2 and MIP-1α) in the bladder. Thus, BCG-IL-15 exerted additive effect on Infiltration of neutrophils in the bladder. BCG-IL-15 may be a promising drug for non-muscle invasive bladder cancer.