Metastatic renal cell carcinoma (mRCC) is a tumor entity with poor prognosis due to limited therapy options. Tyrosine kinase inhibitors (TKIs), the novel targeted agents have been used for the treatment of mRCC and have shown efficacy. Interferon (IFN)-α is also one of the most frequently used agents in immunotherapy. However, drug resistance needs to be overcome to achieve a sufficiently positive effect. Interleukin-6 (IL-6), which induce suppressor of cytokine signaling-3 (SOCS3) expression, is one of the factors associated with poor prognosis of patients with renal cell carcinoma (RCC). To analyze the influence of IL-6 in drug resistance of RCC, anti-IL-6 receptor antibody was used in combination with IFN or TKIs. The SOCS3 mRNA expression level was significantly increased by IFNα stimulation in 786-O RCC cells which were resistant to IFN, but not in ACHN cells that were sensitive to IFN. The overexpression of SOCS3 by gene transfection in ACHN significantly inhibited the growthinhibitory effect of IFNα. An in vivo study demonstrated that coadministration of SOCS3-targeted siRNA promoted INFαinduced cell death and growth suppression in 786-O cell xenograft. SOCS3 could be a key component in the resistance to interferon treatment of renal cell carcinoma. Because SOCS3 is rapidly upregulated by IL-6 and a negative regulator of cytokine signaling, IL-6 expression on RCC cells was also analyzed and the 786-O cells showed the high level of IL-6 mRNA expression under the condition of interferon stimulation. IL-6R antibody, tocilizumab, significantly suppressed cell proliferation in 786-O cells by interferon stimulation accompanied with phosphorylation of STAT1 and inhibited SOCS3 expression. The in vivo effects of combination therapy with tocilizumab and interferon showed significant suppression of 786-O tumor growth in a xenograft model. We also hypothesized that TKI resistance and IL-6 secretion are causally connected. And we found that 786-O RCC cells secrete high IL-6 levels after low dose stimulation with the TKIs sorafenib, sunitinib and pazopanib, inducing activation of AKT-mTOR pathway, NFκB, HIF-2α and VEGF expression. Tocilizumab neutralizes the AKT-mTOR pathway activation and results in reduced proliferation. A combination therapy with tocilizumab and TKI suppresses 786-O tumor growth and inhibits angiogenesis in vivo more efficient than TKI alone. Our findings suggest that IL-6 could induce drug resistance on RCC, and combination therapy of IL-6R inhibitors and IFN/TKIs may represent a novel therapeutic approach for RCC treatment.

To identify the prevalence and predictors of postoperative detrusor underactivity during the early postoperative period after robot-assisted radical prostatectomy. Methods: We carried out a prospective observational study of 64 patients scheduled for robot-assisted radical prostatectomy using urodynamic study before and 1 month after robot-assisted radical prostatectomy. Detrusor underactivity was defined as maximum flow rate ≤15 mL/s and detrusor pressure at maximum flow rate ≤25 cmH 2 O during voiding. Incidences of pre-and postoperative detrusor underactivity were assessed, and predictors of postoperative detrusor underactivity were determined using uni-and multivariate logistic regression analyses. Factors comprised patient characteristics (age, prostate weight etc.), operative factors (surgical duration, nerve sparing etc.) and preoperative urodynamic study parameters (maximum flow rate, bladder contractile index etc.). Results: Pre-and postoperative detrusor underactivity at 1 month after robot-assisted radical prostatectomy were detected in one patient (1.6%) and 24 patients (37.5%), respectively. Univariate analysis selected preoperative maximum flow rate (P = 0.02), detrusor pressure at maximum flow rate (P = 0.04) and bladder contractile index (P < 0.01) as predictors of postoperative detrusor underactivity (odds ratio 0.83, 0.97 and 0.94, respectively). On multivariate analyses, only preoperative bladder contractile index was associated with postoperative detrusor underactivity (P < 0.01; odds ratio 0.94). A cut-off of 102.8 offered optimal accuracy in receiver operating characteristic analysis. Patient characteristics and operative factors were not significantly associated with postoperative detrusor underactivity. Conclusions: A comparatively high prevalence of postoperative detrusor underactivity is observed in patients at 1 month after robot-assisted radical prostatectomy. Patients with preoperative low bladder contractile index have a higher probability of developing early postoperative detrusor underactivity after robot-assisted radical prostatectomy.

No abstract

Enzalutamide (Enz) is a second‐generation androgen receptor (AR) antagonist for castration‐resistant prostate cancer (CRPC) therapy, and it prolongs survival time in these patients. However, during Enz treatment, CRPC patients usually acquire resistance to Enz and often show cross‐resistance to other AR signaling inhibitors. Although glucocorticoid receptor (GR) is involved in this resistance, the role of GR has not yet been clarified. Here, we report that chronic Enz treatment induced GR‐mediated glucose transporter 4 (GLUT4) upregulation, and that upregulation was associated with resistance to Enz and other AR signaling inhibitors. Additionally, inhibition of GLUT4 suppressed cell proliferation in Enz‐resistant prostate cancer cells, which recovered from Enz resistance and cross‐resistance without changes in GR expression. Thus, a combination of Enz and a GLUT4 inhibitor could be useful in Enz‐resistant CRPC patients.

No abstract