IFNγ-Induced IFIT5 Promotes Epithelial-to-Mesenchymal Transition in Prostate Cancer via miRNA Processing.

IFNγ, a potent cytokine known to modulate tumor immunity and tumoricidal effects, is highly elevated in patients with prostate cancer after radiation. In this study, we demonstrate that IFNγ can induce epithelial-to-mesenchymal transition (EMT) in prostate cancer cells via the JAK-STAT signaling pathway, leading to the transcription of IFN-stimulated genes (ISG) such as IFN-induced tetratricopeptide repeat 5 (IFIT5). We unveil a new function of IFIT5 complex in degrading precursor miRNAs (pre-miRNA) that includes pre-miR-363 from the miR-106a-363 cluster as well as pre-miR-101 and pre-miR-128, who share a similar 5'-end structure with pre-miR-363. These suppressive miRNAs exerted a similar function by targeting EMT transcription factors in prostate cancer cells. Depletion of IFIT5 decreased IFNγ-induced cell invasiveness in vitro and lung metastasis in vivo. IFIT5 was highly elevated in high-grade prostate cancer and its expression inversely correlated with these suppressive miRNAs. Altogether, this study unveils a prometastatic role of the IFNγ pathway via a new mechanism of action, which raises concerns about its clinical application.Significance: A unique IFIT5-XRN1 complex involved in the turnover of specific tumor suppressive microRNAs is the underlying mechanism of IFNγ-induced epithelial-to-mesenchymal transition in prostate cancer.See related commentary by Liu and Gao, p. 1032.

Who will pass? Analyzing learner behaviors in MOOCs.

Massive open online courses (MOOCs) have recently gained worldwide attention from educational institutes. MOOCs provide a new option for learning, yet measurable learning benefits of MOOCs still need to be investigated. Collecting data of three MOOCs at Yuan Ze University (YZU), this paper intended to classify learning behaviors among 1489 students on the MOOC platform at YZU. This study further examined learning outcomes in MOOCs by different types of learners. The Ward's hierarchical and k-means non-hierarchical clustering methods were employed to classify types of learners' behavior while they engaged in learning activities on the MOOC platform. Three types of MOOC learners were classified-active learner, passive learner, and bystander. Active learners who submitted assignments on time and frequently watched lecture videos showed a higher completion rate and a better grade in the course. MOOC learners who participated in online discussion forum reported a higher rate of passing the course and a better score than those inactive classmates. The finding of this study suggested that the first 2 weeks was a critical point of time to retain students in MOOCs. MOOC instructors need to carefully design course and detect risk behaviors of students in early of the classes to prevent students from dropping out of the course. The feature design of discussion forum is to provide peer interaction and facilitate online learning. Our results suggested that timely feedback by instructors or facilitators on discussion forum could enhance students' engagement in MOOCs.

Dependence of Two-Photon eGFP Bleaching on Femtosecond Pulse Spectral Amplitude and Phase.

Photobleaching is a key limitation in two-photon imaging of fluorescent proteins with femtosecond pulsed excitation. We present measurements of the dependence of eGFP photobleaching on the spectral amplitude and phase of the pulses used. A strong dependence on the excitation wavelength was confirmed and measured over a 800-950 nm range. A fiber continuum light source and pulse shaping techniques were used to investigate photobleaching with broadband, 15 fs transform limited, pulses with differing spectral amplitude and phase. Narrow band pulses, >150 fs transform limited, typical of femtosecond laser sources used in two-photon imaging applications, were also investigated for their photobleaching dependence on pulse dispersion and bandwidth. The bleach rate for broadband pulses was found to be primarily determined by the second harmonic spectrum of the excitation light. On the other hand, for narrow band excitation pulses with similar center wavelengths improvement in bleach rate was found to be mostly dependent on reducing the pulse length. A simple model to predict the relative bleach rates for broadband pulses is presented and compared to the experimental data.

The role of homeostatic regulation between tumor suppressor DAB2IP and oncogenic Skp2 in prostate cancer growth.

Altered DAB2IP gene expression often detected in prostate cancer (PCa) is due to epigenetic silencing. In this study, we unveil a new mechanism leading to the loss of DAB2IP protein; an oncogenic S-phase kinase-associated protein-2 (Skp2) as E3 ubiquitin ligase plays a key regulator in DAB2IP degradation. In order to unveil the role of Skp2 in the turnover of DAB2IP protein, both prostate cell lines and prostate cancer specimens with a variety of molecular and cell biologic techniques were employed. We demonstrated that DAB2IP is regulated by Skp2-mediated proteasome degradation in the prostate cell lines. Further analyses identified the N-terminal DAB2IP containing the ubiquitination site. Immunohistochemical study exhibited an inverse correlation between DAB2IP and Skp2 protein expression in the prostate cancer tissue microarray. In contrast, DAB2IP can suppressSkp2 protein expression is mediated through Akt signaling. The reciprocal regulation between DAB2IP and Skp2 can impact on the growth of PCa cells. This reciprocal regulation between DAB2IP and Skp2 protein represents a unique homeostatic balance between tumor suppressor and oncoprotein in normal prostate epithelia, which is apparently altered in cancer cells. The outcome of this study has identified new potential targets for developing new therapeutic strategy for PCa.

Slug, a unique androgen-regulated transcription factor, coordinates androgen receptor to facilitate castration resistance in prostate cancer.

Prostate cancer (PCa) becomes lethal when cancer cells develop into castration-resistant PCa (CRPC). Androgen receptor (AR) gene mutation, altered AR regulation, or overexpression of AR often found in CRPC is believed to become one of the key factors to the lethal phenotype. Here we identify Slug, a member of the Snail family of zinc-finger transcription factors associated with cancer metastasis, as a unique androgen-responsive gene in PCa cells. In addition, the presence of constitutively active AR can induce Slug expression in a ligand-independent manner. Slug overexpression will increase AR protein expression and form a complex with AR. In addition, Slug appears to be a novel coactivator to enhance AR transcriptional activities and AR-mediated cell growth with or without androgen. In vivo, elevated Slug expression provides a growth advantage for PCa cells in androgen-deprived conditions. Most importantly, these observations were validated by several data sets from tissue microarrays. Overall, there is a reciprocal regulation between Slug and AR not only in transcriptional regulation but also in protein bioactivity, and Slug-AR complex plays an important role in accelerating the androgen-independent outgrowth of CRPC.

DAB2IP regulates autophagy in prostate cancer in response to combined treatment of radiation and a DNA-PKcs inhibitor.

Radiation therapy (RT) is an effective strategy for the treatment of localized prostate cancer (PCa) as well as local invasion. However, some locally advanced cancers develop radiation resistance and recur after therapy; therefore, the development of radiation-sensitizing compounds is essential for treatment of these tumors. DOC-2/DAB2 interactive protein (DAB2IP), which is a novel member of the Ras-GTPase activating protein family and a regulator of phosphatidylinositol 3-kinase-Akt activity, is often downregulated in aggressive PCa. Our previous studies have shown that loss of DAB2IP results in radioresistance in PCa cells primarily because of accelerated DNA double-strand break (DSB) repair kinetics, robust G(2)/M checkpoint control, and evasion of apoptosis. A novel DNA-PKcs inhibitor NU7441 can significantly enhance the effect of radiation in DAB2IP-deficient PCa cells. This enhanced radiation sensitivity after NU7441 treatment is primarily due to delayed DNA DSB repair. More significantly, we found that DAB2IP-deficient PCa cells show dramatic induction of autophagy after treatment with radiation and NU7441. However, restoring DAB2IP expression in PCa cells resulted in decreased autophagy-associated proteins, such as LC3B and Beclin 1, as well as decreased phosphorylation of S6K and mammalian target of rapamycin (mTOR). Furthermore, the presence of DAB2IP in PCa cells can lead to more apoptosis in response to combined treatment of NU7441 and ionizing radiation. Taken together, NU7441 is a potent radiosensitizer in aggressive PCa cells and DAB2IP plays a critical role in enhancing PCa cell death after combined treatment with NU7441 and radiation.

Helicobacter pylori CagA-mediated IL-8 induction in gastric epithelial cells is cholesterol-dependent and requires the C-terminal tyrosine phosphorylation-containing domain.

Upon infection of the gastric epithelial cells, the Helicobacter pylori cytotoxin-associated gene A (CagA) virulence protein is injected into the epithelial cells via the type IV secretion system (TFSS), which is dependent on cholesterol. Translocated CagA is targeted by the membrane-recruited c-Src family kinases in which a tyrosine residue in the Glu-Pro-Ile-Tyr-Ala (EPIYA)-repeat region, which can be phosphorylated, induces cellular responses, including interleukin-8 (IL-8) secretion and hummingbird phenotype formation. In this study, we explored the role of EPIYA-containing C-terminal domain (CTD) in CagA tethering to the membrane lipid rafts and in IL-8 activity. We found that disruption of the lipid rafts reduced the level of CagA translocation/phosphorylation as well as CagA-mediated IL-8 secretion. By CagA truncated mutagenesis, we identified that the CTD, rather than the N-terminal domain, was responsible for CagA tethering to the plasma membrane and association with detergent-resistant membranes, leading to CagA-induced IL-8 promoter activity. Our results suggest that CagA CTD-containing EPIYAs directly interact with cholesterol-rich microdomains that induce efficient IL-8 secretion in the epithelial cells.

Long-term outcome of radical cystectomy in ESDR patients with bladder urothelial carcinoma.

PURPOSE: The prevalence of urothelial carcinoma is high in dialysis patients. Radical cystectomy is an invasive procedure for patients with recurrent, multiple, or invasive bladder cancer. However, the prognosis of radical cystectomy in dialysis patients has rarely been reported. This study investigates the long-term outcome of radical cystectomy in dialysis patients with bladder urothelial carcinoma. MATERIALS AND METHODS: Clinical data of 193 dialysis patients with bladder urothelial carcinoma were reviewed. Among them, 45 patients received radical cystectomy. Thirty-two patients who received radical cystectomy with concurrent nephroureterectomy were in a stable chronic dialysis condition. In contrast, we performed radical cystectomy without concurrent nephroureterectomy for patients (N = 13) at high surgical risk, such as tumors combined with infection, or hemodynamically unstable. Survival was evaluated using the Kaplan-Meier method. RESULTS: The overall survival rates were 86.7, 80.0, 62.2, 44.4, and 35.6% at 3-months, 6-months, 1-year, 3-years, and 5-years, respectively. Patients who received concurrent nephroureterectomy had a higher mortality rate (13%) than radical cystectomy alone (0.0%) under operative 3 months. However, the patients who received concurrent nephroureterectomy had a higher 5-year survival rate than the group without concurrent nephroureterectomy (43.7 vs. 15.4%). The causes of death included dialysis complications (N = 19, 42.1%), infection (N = 7, 36.8%), and disease metastasis (N = 4, 21.1%). CONCLUSION: Dialysis patients in a stable chronic dialysis condition with recurrent or invasive bladder urothelial carcinoma could have survival benefits in receiving concurrent nephroureterectomy.

Method and outcome of transvesical ureterectomy of the distal ureter in nephroureterectomy of native kidney upper tract urothelial carcinoma ipsilateral to a transplanted kidney.

OBJECTIVES: To analyze outcomes of cases in which we adapted a transvesical ureterectomy technique to remove the distal ureter, including complete removal of the bladder cuff, upon retroperitoneal nephroureterectomy (performed when the diseased native kidney and ureter are ipsilateral to the transplant kidney). METHODS: Nineteen cases of upper urinary tract urothelial carcinoma of the native kidney were diagnosed among the 520 kidney transplant recipients at our kidney transplantation clinic over the last 19 years. Of these 19 patients, 11 had urothelial carcinoma of the native kidney ipsilateral to the transplant kidney. Excluding 2 patients in whom different surgical methods were used, we report 9 patients with nephrectomy and kidney removal through a flank incision retroperitoneally, followed by distal ureteral ureterectomy transvesically through a cystotomy incision. RESULTS: No postoperative surgical complications were encountered among these 9 immunosuppressed kidney transplant recipients. No perioperative deterioration of transplant kidney function was found. One patient with lower ureteral T2/Tis urothelial carcinoma had a minor ureteral wall tear upon pulling-through of the ureteral hiatus, which was clamped immediately. No retroperitoneum or wound metastasis was found during follow-up, which ranged from 3 months to 11 years and 8 months. CONCLUSIONS: This transvesical ureterectomy technique of the distal ureter upon retroperitoneal nephroureterectomy ipsilateral to the transplant kidney is an easy and expeditious approach if the urothelial carcinoma is located in the upper or midureter or renal pelvis.