Novel Insights into Autophagy and Prostate Cancer: A Comprehensive Review

Autophagy is a complex process involved in several cell activities, including tissue growth, differentiation, metabolic modulation, and cancer development. In prostate cancer, autophagy has a pivotal role in the regulation of apoptosis and disease progression. Several molecular pathways are involved, including PI3K/AKT/mTOR. However, depending on the cellular context, autophagy may play either a detrimental or a protective role in prostate cancer. For this purpose, current evidence has investigated how autophagy interacts within these complex interactions. In this article, we discuss novel findings about autophagic machinery in order to better understand the therapeutic response and the chemotherapy resistance of prostate cancer. Autophagic-modulation drugs have been employed in clinical trials to regulate autophagy, aiming to improve the response to chemotherapy or to anti-cancer treatments. Furthermore, the genetic signature of autophagy has been found to have a potential means to stratify prostate cancer aggressiveness. Unfortunately, stronger evidence is needed to better understand this field, and the application of these findings in clinical practice still remains poorly feasible.     

The Role of Cytoskeleton Revealed by Quartz Crystal Microbalance and Digital Holographic Microscopy

The connection between cytoskeleton alterations and diseases is well known and has stimulated research on cell mechanics, aiming to develop reliable biomarkers. In this study, we present results on rheological, adhesion, and morphological properties of primary rat cardiac fibroblasts, the cytoskeleton of which was altered by treatment with cytochalasin D (Cyt-D) and nocodazole (Noc), respectively. We used two complementary techniques: quartz crystal microbalance (QCM) and digital holographic microscopy (DHM). Qualitative data on cell viscoelasticity and adhesion changes at the cell–substrate near-interface layer were obtained with QCM, while DHM allowed the measurement of morphological changes due to the cytoskeletal alterations. A rapid effect of Cyt-D was observed, leading to a reduction in cell viscosity, loss of adhesion, and cell rounding, often followed by detachment from the surface. Noc treatment, instead, induced slower but continuous variations in the rheological behavior for four hours of treatment. The higher vibrational energy dissipation reflected the cell’s ability to maintain a stable attachment to the substrate, while a cytoskeletal rearrangement occurs. In fact, along with the complete disaggregation of microtubules at prolonged drug exposure, a compensatory effect of actin polymerization emerged, with increased stress fiber formation.     

Biological Effects of Cyclin-Dependent Kinase Inhibitors Ribociclib,Palbociclib and Abemaciclib on Breast Cancer Bone Microenvironment

The CDK4/6 inhibitors (CDKi) palbociclib, ribociclib, and abemaciclib are currently approved in combination with anti-estrogen therapy for the treatment of advanced and/or metastatic hormone receptor-positive/HER2-neu-negative breast cancer patients. Given the high incidence of bone metastases in this population, we investigated and compared the potential effects of palbociclib, ribociclib, and abemaciclib on the breast cancer bone microenvironment. Primary osteoclasts (OCs) and osteoblasts (OBs) were obtained from human monocyte and mesenchymal stem cells, respectively. OC function was evaluated by tartrate-resistant acid phosphatase assay and real-time PCR; OB activity was assessed by an alizarin red assay. OB/breast cancer co-culture models were generated via the seeding of MCF-7 cells on a layer of OBs, and tumor cell proliferation was analyzed using flow cytometry. Here, we showed that ribociclib, palbociclib, and abemaciclib exerted similar inhibitory effects on the OC differentiation and expression of bone resorption markers without affecting OC viability. On the other hand, the three CDKi did not affect the ability of OB to produce bone matrix, even if the higher doses of palbociclib and abemaciclib reduced the OB viability. In OB/MCF-7 co-culture models, palbociclib demonstrated a lower anti-tumor effect than ribociclib and abemaciclib. Overall, our results revealed the direct effects of CDKi on the tumor bone microenvironment, highlighting differences potentially relevant for clinical practice.     

Comparing surface residue transfer efficiencies to hands using polar and nonpolar fluorescent tracers

Transfer of chemicals from contaminated surfaces such as foliage, floors, and furniture is a potentially significant source of both occupational exposure and children's residential exposure. Increased understanding of relevant factors influencing transfers from contaminated surfaces to skin and resulting dermal-loading will reduce uncertainty in exposure assessment. In a previously reported study, a fluorescence imaging system was developed, tested, and used to measure transfer of riboflavin residues from surfaces to hands. Parameters evaluated included surface type, surface loading, contact motion, pressure, duration, and skin condition. Results of the initial study indicated that contact duration and pressure were not significant for the range of values tested, but that there are potentially significant differences in transfer efficiencies of different compounds. In the study reported here, experimental methods were refined and additional transfer data were collected. A second fluorescent tracer, Uvitex OB, with very different physicochemical properties than riboflavin, was also evaluated to better characterize the range of transfers that may be expected for a variety of compounds. Fluorescent tracers were applied individually to surfaces and transfers to skin were measured after repeated hand contacts with the surface. Additional trials were conducted to compare transfer of tracers and co-applied pesticide residues. Results of this study indicate that dermal loadings of both tracers increase through the seventh brief contact. Dermal loading of Uvitex tends to increase at a higher rate than dermal loadings of riboflavin. Measurement of co-applied tracer and pesticide suggest results for these two tracers may provide reasonable bounding estimates of pesticide transfer.     

Metabolic Syndrome and Male Fertility: Beyond Heart Consequences of a Complex Cardiometabolic Endocrinopathy

Metabolic syndrome (MetS) is a highly prevalent condition among adult males, affecting up to 41% of men in Europe. It is characterized by the association of obesity, hypertension, and atherogenic dyslipidemia, which lead to premature morbidity and mortality due to cardiovascular disease (CVD). Male infertility is another common condition which accounts for about 50% of cases of couple infertility worldwide. Interestingly, male infertility and MetS shares several risk factors (e.g., smoking, ageing, physical inactivity, and excessive alcohol consumption), leading to reactive oxygen species (ROS) production and increased oxidative stress (OS), and resulting in endothelial dysfunction and altered semen quality. Thus, the present narrative review aims to discuss the pathophysiological mechanisms which link male infertility and MetS and to investigate the latest available evidence on the reproductive consequences of MetS.     

Lipidomic Approaches to Study HDL Metabolism in Patients with Central Obesity Diagnosed with Metabolic Syndrome

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors characterised by central obesity, atherogenic dyslipidaemia, and changes in the circulating lipidome; the underlying mechanisms that lead to this lipid remodelling have only been partially elucidated. This study used an integrated “omics” approach (untargeted whole serum lipidomics, targeted proteomics, and lipoprotein lipidomics) to study lipoprotein remodelling and HDL composition in subjects with central obesity diagnosed with MetS (vs. controls). Compared with healthy subjects, MetS patients showed higher free fatty acids, diglycerides, phosphatidylcholines, and triglycerides, particularly those enriched in products of de novo lipogenesis. On the other hand, the “lysophosphatidylcholines to phosphatidylcholines” and “cholesteryl ester to free cholesterol” ratios were reduced, pointing to a lower activity of lecithin cholesterol acyltransferase (LCAT) in MetS; LCAT activity (directly measured and predicted by lipidomic ratios) was positively correlated with high-density lipoprotein cholesterol (HDL-C) and negatively correlated with body mass index (BMI) and insulin resistance. Moreover, many phosphatidylcholines and sphingomyelins were significantly lower in the HDL of MetS patients and strongly correlated with BMI and clinical metabolic parameters. These results suggest that MetS is associated with an impairment of phospholipid metabolism in HDL, partially led by LCAT, and associated with obesity and underlying insulin resistance. This study proposes a candidate strategy to use integrated “omics” approaches to gain mechanistic insights into lipoprotein remodelling, thus deepening the knowledge regarding the molecular basis of the association between MetS and atherosclerosis.     

Oxidation resistant ceramic foam from a silicone preceramic polymer/polyurethane blend

Silicon oxycarbide (SiOC) ceramic foams, produced by the pyrolysis of a foamed blend of a methylsilicone preceramic polymer and polyurethane (PU) in a 1/1 wt.% ratio, exhibit excellent physical and mechanical properties. The proposed process allows to easily modify the density and morphology of the foams, making them suitable for several engineering applications. However, it has been shown that, due to residual carbon present in the oxycarbide phase after pyrolysis, the foams are subjected to an oxidation process that reduces their strength after high temperature exposure to air (12 h 1200°C). A modified process, employing the same silicone resin preceramic polymer but a much lower PU content (silicone resin/PU=5.25/1 wt.% ratio), has been developed and is reported in this paper. Microstructural investigations showed that carbon rich regions deriving from the decomposition of the polyurethane template are still present in the SiOC foam, but have a much smaller dimension than those found in foams with a higher PU content. Thermal gravimetric studies performed in air or oxygen showed that the low-PU containing ceramic foams display an excellent oxidation resistance, because the carbon-rich areas are embedded inside the struts or cell walls and are thus protected by the dense silicon oxycarbide matrix surrounding them. SiOC foams obtained with the novel process are capable to maintain their mechanical strength after oxidation treatments at 800 and 1200°C (12 h), while SiOC foams obtained with a higher amount of PU show about a 30% strength decrease after oxidation at 1200°C (12 h).     

Dispersing Behavior of Hydroxyapatite Powders Produced by Wet-Chemical Synthesis

Three hydroxyapatite powders with different surface properties were produced by wet-chemical synthesis and characterized. The electrokinetic properties of powders dispersed in water were investigated by electroacoustic spectroscopy measurements. The different surface reactivity (pH_iep and ζ potential versus pH curves) was related to the interplay of dissolution and adsorption of Ca²⁺ ions. With a view toward the preparation of porous bodies by sponge impregnation, the behavior of powder suspensions was studied. Four deflocculants were tested, and the optimum dispersing conditions for each powder were found. Anionic polyelectrolytes resulted in the best effective dispersing agent, with different optimum amounts added to the suspensions.     

A cyclic CCK8 analogue selective for the cholecystokinin type A receptor: design, synthesis, NMR structure and binding measurements

A cyclic CCK8 analogue, cyclo(29,34)[Dpr(29),Lys(34)]-CCK8 (Dpr=L-2,3-diaminopropionic acid), has been designed on the basis of the NMR structure of the bimolecular complex between the N-terminal fragment of the CCK(A) receptor and its natural ligand CCK8. The conformational features of cyclo(29,34)[Dpr(29),Lys(34)]-CCK8 have been determined by NMR spectroscopy in aqueous solution and in water containing DPC-d(38) micelles (DPC=dodecylphosphocholine). The structure of the cyclic peptide in aqueous solution is found to be in a relaxed conformation, with the backbone and Dpr29 side chain atoms making a planar ring and the N-terminal tripeptide extending approximately along the plane of this ring. In DPC/water, the cyclic peptide adopts a "boat-shaped" conformation, which is more compact than that found in aqueous solution. The cyclic constraint between the Dpr29 side chain and the CCK8 carboxyl terminus (Lys34) introduces a restriction in the backbone conformational freedom. However, the interaction of cyclo(29,34)[Dpr(29),Lys(34)]-CCK8 with the micelles still plays an important role in the stabilisation of the bioactive conformation. A careful comparison of the NMR structure of the cyclic peptide in a DPC micelle aqueous solution with the structure of the rationally designed model underlines that the turn-like conformation in the Trp30-Met31 region is preserved, such that the Trp30 and Met31 side chains can adopt the proper spatial orientation to interact with the CCK(A) receptor. The binding properties of cyclo(29,34)[Dpr(29),Lys(34)]-CCK8 to the N-terminal receptor fragment have been investigated by fluorescence spectroscopy in a micellar environment. Estimates of the apparent dissociation constant, K(d), were in the range of 70-150 nM, with a mean value of 120+/-27 nM. Preliminary nuclear medicine studies on cell lines transfected with the CCK(A) receptor indicate that the sulfated-Tyr derivative of cyclo(29,34)[Dpr(29),Lys(34)]-CCK8 displaces the natural ligand with an IC(50) value of 15 microM.     

Thermal and mechanical properties of PES/PTFE composites and nanocomposites

Polyethersulphone/polytetrafluoroethylene (PES/PTFE) nanocomposites and composites were prepared by precipitation of PES into a PTFE latex‐containing nanoparticles. Different samples were obtained by varying the relative ratio between PES and PTFE. The complex crystallization process, discussed within the fractionated crystallization frame, allowed to identify and quantify different dispersion degree of the PTFE nanoparticles within the PES matrix. The different samples were thus divided into nanocomposite and composites. The effect of crystalline PTFE domains on the mobility of PES was investigated and discussed. The dynamic‐mechanical behavior was explained in terms of the particle aggregation state. The mechanical properties of the PES/PTFE composites were found to depend on both the dispersion and the concentration of the PTFE nanoparticles. In the glassy state the stiffness of the materials was found to increase with the dispersion degree, resulting higher for the nanocomposite with respect to composites. On the contrary, in the rubbery state the modulus was found proportional to the PTFE nanoparticles concentration, resulting higher in the composites with respect to the nanocomposite. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3624–3633, 2013