Intrinsically disordered proteins and conformational noise: Implications in cancer

Intrinsically disordered proteins, IDPs, are proteins that lack a rigid 3D structure under physiological conditions, at least in vitro. Despite the lack of structure, IDPs play important roles in biological processes and transition from disorder to order upon binding to their targets. With multiple conformational states and rapid conformational dynamics, they engage in myriad and often “promiscuous” interactions. These stochastic interactions between IDPs and their partners, defined here as conformational noise, is an inherent characteristic of IDP interactions. The collective effect of conformational noise is an ensemble of protein network configurations, from which the most suitable can be explored in response to perturbations, conferring protein networks with remarkable flexibility and resilience. Moreover, the ubiquitous presence of IDPs as transcriptional factors and, more generally, as hubs in protein networks, is indicative of their role in propagation of transcriptional (genetic) noise. As effectors of transcriptional and conformational noise, IDPs rewire protein networks and unmask latent interactions in response to perturbations. Thus, noise-driven activation of latent pathways could underlie state-switching events such as cellular transformation in cancer. To test this hypothesis, we created a model of a protein network with the topological characteristics of a cancer protein network and tested its response to a perturbation in presence of IDP hubs and conformational noise. Because numerous IDPs are found to be epigenetic modifiers and chromatin remodelers, we hypothesize that they could further channel noise into stable, heritable genotypic changes

Cancer/Testis antigens as potential predictors of biochemical recurrence of prostate cancer following radical prostatectomy

<p>Abstract</p> <p>Background</p> <p>The Cancer/Testis Antigens (CTAs) are an important group of proteins that are typically restricted to the testis in the normal adult but are aberrantly expressed in several types of cancers. As a result of their restricted expression patterns, the CTAs could serve as unique biomarkers for cancer diagnosis/prognosis. The aim of this study was to identify promising CTAs that are associated with prostate cancer (PCa) recurrence following radical prostatectomy (RP).</p> <p>Methods</p> <p>The expression of 5 CTAs was measured by quantitative multiplex real-time PCR using prostate tissue samples obtained from 72 patients with apparently clinically localized PCa with a median of two years follow-up (range, 1 to 14 years).</p> <p>Results</p> <p>The expression of CTAs namely, CEP55, NUF2, PBK and TTK were significantly higher while PAGE4 was significantly lower in patients with recurrent disease. All CTAs with the exception of TTK were significantly correlated with the prostatectomy Gleason score, but none were correlated with age, stage, or preoperative PSA levels. In univariate proportional hazards models, CEP55 (HR = 3.59, 95% CI: 1.50-8.60), p = 0.004; NUF2 (HR = 2.28, 95% CI: 1.11-4.67), p = 0.024; and PAGE4 (HR = 0.44, 95% CI: 0.21-0.93), p = 0.031 were significantly associated with the risk of PCa recurrence. However, the results were no longer significant after adjustment for prostatectomy Gleason score.</p> <p>Conclusions</p> <p>To our knowledge, this is the first study to identify CTAs as biomarkers that can differentiate patients with recurrent and non-recurrent disease following RP and underscores its potential impact on PCa prognosis and treatment.</p

Orally Bioavailable Androgen Receptor Degrader, Potential Next-Generation Therapeutic for Enzalutamide-Resistant Prostate Cancer

Acknowledgement. BGS acknowledges work performed at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility. VB acknowledges Laboratory Directed Research and Development program of Oak Ridge National Laboratory, managed by UTBattelle, LLC, for the U.S. Department of Energy.Peer reviewedPostprin

The Cancer/Testis Antigen Prostate-associated Gene 4 (PAGE4) Is a Highly Intrinsically Disordered Protein

The cancer/testis antigens (CTAs) are an important group of heterogeneous proteins that are predominantly expressed in the testis in the normal human adult but are aberrantly expressed in several types of cancers. Prostate-associated gene 4 (PAGE4) is a member of the CT-X family of CTAs that in addition to testis, is highly expressed in the fetal prostate, and may also play an important role both in benign and malignant prostate diseases. However, the function of this gene remains poorly understood. Here, we show that PAGE4 is a highly (100%) intrinsically disordered protein (IDP). The primary protein sequence conforms to the features of a typical IDP sequence and the secondary structure prediction algorithm metaPrDOS strongly supported this prediction. Furthermore, SDS-gel electrophoresis and analytical size exclusion chromatography of the recombinant protein revealed an anomalous behavior characteristic of IDPs. UV circular dichroism (CD) and NMR spectroscopy confirmed that PAGE4 is indeed a highly disordered protein. In further bioinformatic analysis, the PredictNLS algorithm uncovered a potential nuclear localization signal, whereas the algorithm DBS-Pred returned a 99.1% probability that PAGE4 is a DNA-binding protein. Consistent with this prediction, biochemical experiments showed that PAGE4 preferentially binds a GC-rich sequence. Silencing PAGE4 expression induced cell death via apoptosis and in mice carrying PCa xenografts, siRNA-mediated knockdown of the PAGE4 mRNA attenuated tumor growth in vivo. Furthermore, overexpressing PAGE4 protected cells from stress-induced death. To our knowledge, PAGE4 is the first example of a CTA that is an IDP with an anti-apoptotic function

Tools to identify the men with prostate cancer most appropriate for active surveillance?

A great deal of effort is underway in order to identify those men with prostate cancer felicitous for active surveillance with greater precision than that afforded to us today. In the manuscript by Irshad et al. the authors evaluate a novel set of genes associated with senescence and aging as tools that can provide guidance regarding the indolent nature of an individual's prostate cancer with validation using both mRNA and protein analyses. While additional studies are required to understand the full impact of these findings, the innovative approach taken enhances our understanding of distinct phenotypes of prostate cancer

RANDOMIZED, PLACEBO-CONTROLLED STUDY TO EVALUATE THE EFFICACY, SAFETY, AND TOLERABILITY OF BENZOCAINE WIPES IN SUBJECTS WITH PREMATURE EJACULATION

Aim This study investigated the efficacy and safety of benzocaine wipes (PREBOOST) applied to the penis prior to intercourse for the treatment of men with premature ejaculation. Materials and methods The study utilized the local anesthetic benzocaine, in the form of wipes, for topical application to the glans penis prior to sexual intercourse. The design included three phases: screening and baseline, blinded randomized controlled, and an open-label phase with crossover of the placebo group to open-label active treatment. The two co-primary efficacy measures were the intravaginal ejaculatory latency time (IELT) measured by stopwatch, and the patient-reported outcome measured by the Index of Premature Ejaculation (IPE). Additional efficacy evaluation included a responder analysis using a predetermined 120s improvement in IELT as a responder threshold. Safety evaluation included patient-reported events along with a physical examination. Results The treatment phase showed a statistically significant increase from the baseline, in the treatment group (mean 165s) compared with the placebo group (mean 110s), P<0.007. After the second month of use, the treatment group had a mean IELT of 329.70s (±21.37 SE) in comparison to the placebo group which had a mean IELT of 110.10s (±9.90 SE) (P=0.001). The open-label phase showed further increase in IELT in the treatment group and a statistically significant increase in IELT in the placebo/ crossover group. Using the IPE, the men in the treatment group reported significantly higher sexual satisfaction (P=0.047) and greater improvement in distress (P=0.020) with a trend toward improve-ment in the ejaculatory control domain scores (P=0.093). The responder analysis showed a statisti-cally significant response to the use of benzocaine versus placebo, attesting an IELT increase that was clinically meaningful. Benzocaine wipes were well tolerated by subjects and partners. Conclusion This randomized, placebo controlled clinical trial with crossover design showed that benzocaine wipes applied topically to the penis prior to sexual intercourse had a statistically significant prolongation of time to ejaculation, a clinically meaningful benefit, in the treatment of premature ejaculation. Furthermore, benzocaine wipes were well tolerated by the subjects and no evidence of transference to their female partners