Influence of regular aspirin intake on PSA values, prostate cancer incidence and overall survival in a prospective screening trial (ERSPC Aarau).

OBJECTIVES: To analyze the influence of aspirin (ASA) intake on PSA values and prostate cancer (PCa) development in a prospective screening study cohort. METHODS: 4314 men from the Swiss section of the European Randomized Study of Screening for Prostate Cancer (ERSPC) were included. A transrectal prostate biopsy was performed in men with a PSA level ≥ 3 ng/ml. Mortality data were obtained through registry linkages. PCa incidence and grade, total PSA, free-to-total PSA and overall survival were compared between ASA users and non-users. RESULTS: Median follow-up time was 9.6 years. In 789 men (18.3%) using aspirin [ASA +], the overall PCa incidence was significantly lower (6.8% vs. 9.6%, p = 0.015), but the multivariate Cox regression analysis showed no significant decrease in risk of PCa diagnosis (HR 0.84, p = 0.297). Total PSA values were significantly lower in ASA users for both baseline (1.6 vs. 1.8 ng/ml, p = 0.007) and follow-up visits (1.75 vs. 2.1 ng/ml, p < 0.001). Multivariate Cox regression analysis predicted significantly higher overall mortality risk among ASA users (HR 1.46, p = 0.009). CONCLUSIONS: In our study population, PCa incidence was significantly reduced among patients on aspirin. While we did not observe a statistically significant PCa risk reduction during the follow-up period, we found lower PSA values among ASA users compared to non-users, with a more distinct difference after 4 years of ASA intake, suggesting a cumulative effect and a potential protective association between regular ASA intake and PCa development. As for clinical practice, lowering PSA cutoff values by 0.4 ng/ml could be considered in long-term ASA users to avoid a potential bias towards delayed PCa detection.

Enhanced bone regeneration in rat calvarial defects through BMP2 release from engineered poly(ethylene glycol) hydrogels.

The clinical standard therapy for large bone defects, typically addressed through autograft or allograft donor tissue, faces significant limitations. Tissue engineering offers a promising alternative strategy for the regeneration of substantial bone lesions. In this study, we harnessed poly(ethylene glycol) (PEG)-based hydrogels, optimizing critical parameters including stiffness, incorporation of arginine-glycine-aspartic acid (RGD) cell adhesion motifs, degradability, and the release of BMP2 to promote bone formation. In vitro we demonstrated that human bone marrow derived stromal cell (hBMSC) proliferation and spreading strongly correlates with hydrogel stiffness and adhesion to RGD peptide motifs. Moreover, the incorporation of the osteogenic growth factor BMP2 into the hydrogels enabled sustained release, effectively inducing bone regeneration in encapsulated progenitor cells. When used in vivo to treat calvarial defects in rats, we showed that hydrogels of low and intermediate stiffness optimally facilitated cell migration, proliferation, and differentiation promoting the efficient repair of bone defects. Our comprehensive in vitro and in vivo findings collectively suggest that the developed hydrogels hold significant promise for clinical translation for bone repair and regeneration by delivering sustained and controlled stimuli from active signaling molecules.

Molecular and biophysical mechanisms regulating hypertrophic differentiation in chondrocytes and mesenchymal stem cells.

Chondrocyte hypertrophy is one of the key physiological processes involved in the longitudinal growth of long bones, yet the regulation of hypertrophy is also becoming increasingly relevant for clinical application of mesenchymal stem cells (MSCs) and screening for drugs to treat hypertrophic osteoarthritis. The extraordinary cell volume increase during hypertrophy is accompanied by an up-regulation of collagen X, matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF), all which are targets of the runt-related transcription factor 2 (Runx2). Many pathways, including parathyroid hormone-related protein (PTHrP)/Indian Hedgehog, Wingless/Int (Wnt)/ß-catenin, and transforming growth factor beta (TGF-ß)/Sma and Mad Related Family (Smad) pathways, can regulate hypertrophy, but factors as diverse as hypoxia, co-culture, epigenetics and biomaterial composition can also potently affect Runx2 expression. Control of hypertrophic differentiation can be exploited both for cartilage repair, where a stable phenotype is desired, but also in bone regeneration, where hypertrophic cartilage could act as a template for endochondral bone formation. We hope this review will motivate the design of novel engineered microenvironments for skeletal regeneration applications.

Extracellular Vesicles from 3D Engineered Microtissues Harbor Disease-Related Cargo Absent in EVs from 2D Cultures.

Engineered microtissues that recapitulate key properties of the tumor microenvironment can induce clinically relevant cancer phenotypes in vitro. However, their effect on molecular cargo of secreted extracellular vesicles (EVs) has not yet been investigated. Here, the impact of hydrogel-based 3D engineered microtissues on EVs secreted by benign and malignant prostate cells is assessed. Compared to 2D cultures, yield of EVs per cell is significantly increased for cancer cells cultured in 3D. Whole transcriptome sequencing and proteomics of 2D-EV and 3D-EV samples reveal stark contrasts in molecular cargo. For one cell type in particular, LNCaP, enrichment is observed exclusively in 3D-EVs of GDF15, FASN, and TOP1, known drivers of prostate cancer progression. Using imaging flow cytometry in a novel approach to validate a putative EV biomarker, colocalization in single EVs of GDF15 with CD9, a universal EV marker, is demonstrated. Finally, in functional assays it is observed that only 3D-EVs, unlike 2D-EVs, confer increased invasiveness and chemoresistance to cells in 2D. Collectively, this study highlights the value of engineered 3D microtissue cultures for the study of bona fide EV cargoes and their potential to identify biomarkers that are not detectable in EVs secreted by cells cultured in standard 2D conditions.

An Automatable Hydrogel Culture Platform for Evaluating Efficacy of Antibody-Based Therapeutics in Overcoming Chemoresistance.

The microenvironment plays a major role in conferring chemoresistance to cancer cells. In order to better inform clinical response to chemoresistance, preclinical models that recapitulate its hallmark features are needed to enable screening for resistance-specific therapeutic targets. A novel platform for seeding cancer cells in 3D hydrogels is presented utilizing derivatives of chitosan and alginate that, critically, is amenable to high throughput screening: cell seeding in hydrogels, media changes, dosing of anticancer compounds, and cell viability assays are all automated using a standard and commercially available liquid handling robot. Culture in these hydrogels elicits resistance in ovarian, lung, and prostate cancer cells to treatment by doxorubicin and paclitaxel. In correlation, proteomics analysis of SKOV3 cells cultured in 3D reveals enrichment of proteins associated with extreme drug resistance including HMOX1 and ALDH2. Subsequently, therapeutic antibodies targeted to tumor-associated antigens upregulated in 3D cultures are shown to have higher efficacy compared to 2D cultures. Collectively, this automated 3D cell culture platform provides a powerful tool with utility in identification of drugs that may overcome chemoresistance.

Engineered Microtissues Formed by Schiff Base Crosslinking Restore the Chondrogenic Potential of Aged Mesenchymal Stem Cells.

A universal method for reproducibly directing stem cell differentiation remains a major challenge for clinical applications involving cell-based therapies. The standard approach for chondrogenic induction by micromass pellet culture is highly susceptible to interdonor variability. A novel method for the fabrication of condensation-like engineered microtissues (EMTs) that utilizes hydrophilic polysaccharides to induce cell aggregation is reported here. Chondrogenesis of mesenchymal stem cells (MSCs) in EMTs is significantly enhanced compared to micromass pellets made by centrifugation measured by type II collagen gene expression, dimethylmethylene blue assay, and histology. MSCs from aged donors that fail to differentiate in pellet culture are successfully induced to synthesize cartilage-specific matrix in EMTs under identical media conditions. Furthermore, the EMT polysaccharides support the loading and release of the chondroinduction factor transforming growth factor ß3 (TGF-ß3). TGF-ß-loaded EMTs (EMT(+TGF) ) facilitate cartilaginous tissue formation during culture in media not supplemented with the growth factor. The clinical potential of this approach is demonstrated in an explant defect model where EMT(+TGF) from aged MSCs synthesize de novo tissue containing sulfated glycosaminoglycans and type II collagen in situ.

GFOGER-modified MMP-sensitive polyethylene glycol hydrogels induce chondrogenic differentiation of human mesenchymal stem cells.

The cellular microenvironment plays a crucial role in directing proliferation and differentiation of stem cells. Cells interact with their microenvironment via integrins that recognize certain peptide sequences of extracellular matrix proteins. This receptor-ligand binding has profound impact on cell fate. Interactions of human bone marrow mesenchymal stem cells (hMSCs) with the triple helical collagen mimetic, GPC(GPP)5-GFOGER-(GPP)5GPC-NH2, and the fibronectin adhesion peptide, RGD, were studied in degradable or nondegradable polyethylene glycol (PEG) gels formed by Michael-type addition chemistry. Proliferation, cytoskeletal morphology, and chondrogenic differentiation of encapsulated hMSCs were evaluated. The hMSCs adopted a highly spread morphology within the GFOGER-modified gels, whereas RGD induced a star-like spreading of the cells. hMSCs within GFOGER-modified degradable gels had a high proliferation rate compared with cells in peptide-free gels (p=0.017). Gene expression of type II collagen was highest in GFOGER-modified degradable gels after 21 days. Peptide incorporation increased GAG production in degradable gels after 7 and 21 days and GFOGER-modified degradable hydrogels had on average the highest GAG content, a finding that was confirmed by Alcian blue staining. In conclusion, the GFOGER peptide enhances proliferation in degradable PEG gels and provides a better chondrogenic microenvironment compared with the RGD peptide.