The identification of fibroblasts and cancer-associated fibroblasts from human cancer tissue using surface markers is difficult, especially because the markers used currently are usually not expressed solely by fibroblasts, and the identification of fibroblast-specific surface molecules is still under investigation. It was aimed to compare three commercially available antibodies in the detection of different surface epitopes of fibroblasts (anti-fibroblast, fibroblast activation protein α, and fibroblast surface protein). The specificity of their expression, employing fibroblast cell lines and tumor-derived fibroblasts from breast and prostate tissues was investigated. Both the established fibroblast cell line HFF-1 and ex vivo primary fibroblasts isolated from breast and prostate cancer tissues expressed the tested surface markers to different degrees. Surprisingly, those markers were expressed also by permanent cell lines of epithelial origin, both benign and cancer-derived (breast-cell lines MCF 10A, HMLE and prostate-cell lines BPH-1, DU 145, and PC-3). The expression of fibroblast activation protein α increased on the surface of previously described models of epithelial cells undergoing epithelial-to-mesenchymal transition in response to treatment with TGF-β1. To prove the co-expression of the fibroblast markers on cells of epithelial origin, we used freshly dissociated human prostate and breast cancer tissues. The results confirmed the co-expression of anti-fibroblast and fibroblast surface protein on CD31/CD45-negative/EpCAM-positive epithelial cells. In summary, our data support the findings that the tested fibroblast markers are not fibroblast specific and may be expressed also by cells of epithelial origin (e.g., cells undergoing EMT). Therefore, the expression of these markers should be interpreted with caution, and the combination of several epitopes for both positive (anti-fibroblast or fibroblast activation protein α) and negative (EpCAM) identification of fibroblasts from breast and prostate tumor tissues is advised. © 2017 International Society for Advancement of Cytometry.

The DNA damage checkpoints provide an anti-cancer barrier in diverse tumour types, however this concept has remained unexplored in prostate cancer (CaP). Furthermore, targeting DNA repair defects by PARP1 inhibitors (PARPi) as a cancer treatment strategy is emerging yet requires suitable predictive biomarkers. To address these issues, we performed immunohistochemical analysis of multiple markers of DNA damage signalling, oxidative stress, DNA repair and cell cycle control pathways during progression of human prostate disease from benign hyperplasia, through intraepithelial neoplasia to CaP, complemented by genetic analyses of TMPRSS2-ERG rearrangement and NQO1, an anti-oxidant factor and p53 protector. The DNA damage checkpoint barrier (γH2AX, pATM, p53) mechanism was activated during CaP tumorigenesis, albeit less and with delayed culmination compared to other cancers, possibly reflecting lower replication stress (slow proliferation despite cases of Rb loss and cyclin D1 overexpression) and progressive loss of ATM activator NKX3.1. Oxidative stress (8-oxoguanine lesions) and NQO1 increased during disease progression. NQO1 genotypes of 390 men did not indicate predisposition to CaP, yet loss of NQO1 in CaP suggested potential progression-opposing tumour suppressor role. TMPRSS2-ERG rearrangement and PTEN loss, events sensitizing to PARPi, occurred frequently along with heterogeneous loss of DNA repair factors 53BP1, JMJD1C and Rev7 (all studied here for the first time in CaP) whose defects may cause resistance to PARPi. Overall, our results reveal an unorthodox DNA damage checkpoint barrier scenario in CaP tumorigenesis, and provide novel insights into oxidative stress and DNA repair, with implications for biomarker guidance of future targeted therapy of CaP.

Background Castration‐resistant prostate cancer (PCa) represents a serious health challenge. Based on mechanistically‐supported rationale we explored new therapeutic options based on clinically available drugs with anticancer effects, including inhibitors of PARP1 enzyme (PARPi), and histone deacetylases (vorinostat), respectively, and disulfiram (DSF, known as alcohol‐abuse drug Antabuse) and its copper‐chelating metabolite CuET that inhibit protein turnover. Methods Drugs and their combination with ionizing radiation (IR) were tested in various cytotoxicity assays in three human PCa cell lines including radio‐resistant stem‐cell like derived cells. Mechanistically, DNA damage repair, heat shock and unfolded protein response (UPR) pathways were assessed by immunofluorescence and immunoblotting. Results We observed enhanced sensitivity to PARPi/IR in PC3 cells consistent with lower homologous recombination (HR) repair. Vorinostat sensitized DU145 cells to PARPi/IR and decreased mutant p53. Vorinostat also impaired HR‐mediated DNA repair, as determined by Rad51 foci formation and downregulation of TOPBP1 protein, and overcame radio‐resistance of stem‐cell like DU145‐derived cells. All PCa models responded well to CuET or DSF combined with copper. We demonstrated that DSF interacts with copper in the culture media and forms adequate levels of CuET indicating that DSF/copper and CuET may be considered as comparable treatments. Both DSF/copper and CuET evoked hallmarks of UPR in PCa cells, documented by upregulation of ATF4, CHOP and phospho‐eIF2α, with ensuing heat shock response encompassing activation of HSF1 and HSP70. Further enhancing the cytotoxicity of CuET, combination with an inhibitor of the anti‐apoptotic protein survivin (YM155, currently undergoing clinical trials) promoted the UPR‐induced toxicity, yielding synergistic effects of CuET and YM155. Conclusions We propose that targeting genotoxic and proteotoxic stress responses by combinations of available drugs could inspire innovative strategies to treat castration‐resistant PCa.

To the best of our knowledge, this is the first documentation of cytokine GDF-15 presence in follicular fluid. Its concentration was not associated with donor/patient fertility status. Our data also show that GDF-15 is expressed and inducible in both normal healthy and cancerous granulosa cells, as well as in oocytes.

No abstract

Prostate cancer (PCa) is the second leading cause of cancer-related deaths in men in Western countries, and there is still an urgent need for a better understanding of PCa progression to inspire new treatment strategies. Skp2 is a substrate-recruiting component of the E3 ubiquitin ligase complex, whose activity is regulated through neddylation. Slug is a transcriptional repressor involved in the epithelial-to-mesenchymal transition, which may contribute to therapy resistance. Although Skp2 has previously been associated with a mesenchymal phenotype and prostate cancer progression, the relationship with Slug deserves further elucidation. We have previously shown that a high Gleason score (≥8) is associated with higher Skp2 and lower E-cadherin expression. In this study, significantly increased expression of Skp2, AR, and Slug, along with E-cadherin downregulation, was observed in primary prostate cancer in patients who already had lymph node metastases. Skp2 was slightly correlated with Slug and AR in the whole cohort (Rs 0.32 and 0.37, respectively), which was enhanced for both proteins in patients with high Gleason scores (Rs 0.56 and 0.53, respectively) and, in the case of Slug, also in patients with metastasis to lymph nodes (Rs 0.56). Coexpression of Skp2 and Slug was confirmed in prostate cancer tissues by multiplex immunohistochemistry and confocal microscopy. The same relationship between these two proteins was observed in three sets of prostate epithelial cell lines (PC3, DU145, and E2) and their mesenchymal counterparts. Chemical inhibition of Skp2, but not RNA interference, modestly decreased Slug protein in PC3 and its docetaxel-resistant subline PC3 DR12. Importantly, chemical inhibition of Skp2 by MLN4924 upregulated p27 and decreased Slug expression in PC3, PC3 DR12, and LAPC4 cells. Novel treatment strategies targeting Skp2 and Slug by the neddylation blockade may be promising in advanced prostate cancer, as recently documented for other aggressive solid tumors.

a , Ales Vidlar a , Vladimir Student aAims. With the introduction of magnetic resonance imaging in the diagnosis of prostate cancer and its use in targeted prostate biopsy, an increased incidence of anterior-predominant prostate cancer (APC) has been observed. Methods. We enrolled 200 patients who underwent radical prostatectomy at our department between 12/2017 and 04/2019. We evaluated tumour location in the individual segments of the prostate, index tumour location and volume, and compared the postoperative stage, Gleason score, grade group (GG), and the presence of extraprostatic extension (EPE) in APC and posterior prostate cancer (PPC). We assessed the rate of MRI scans prior to prostate surgery as well as the influence of family history and PSA on the presence of APC. Results. We found a significantly higher rate of anterior tumours than previously reported (37%) and confirmed that these tumours are diagnosed with a significantly larger index tumour volume (P=0.003). We also showed that a mere 6.76% of APCs were low-risk tumours not requiring radical treatment. Furthermore, anterior tumours were found significantly more often (P=0.001) in patients who underwent preoperative MRI. No differences were observed between PSA values, family history, presence of EPE, or locally advanced disease in APC vs. PPC. Conclusions. The frequency of anterior tumours is higher than previously thought, and they include tumours requiring radical treatment. When these tumours are neglected, it may lead to patient undertreatment with impact on their life prognosis. Thus, we consider the use of MRI-targeted prostate biopsy to be a necessity both for ruling out APC in the case of repeatedly negative prostate biopsies and, in particular, before patient inclusion in active surveillance.

Rationale: Small 225 Ac-labeled prostate-specific membrane antigen (PSMA)-targeted radioconjugates have been described for targeted alpha therapy of metastatic castration-resistant prostate cancer. Transient binding to serum albumin as a highly abundant, inherent transport protein represents a commonly applied strategy to modulate the tissue distribution profile of such low-molecular-weight radiotherapeutics and to enhance radioactivity uptake into tumor lesions with the ultimate objective of improved therapeutic outcome. Methods: Two ligands mcp-M-alb-PSMA and mcp-D-alb-PSMA were synthesized by combining a macropa-derived chelator with either one or two lysine-ureido-glutamate-based PSMA-and 4-(p-iodophenyl)butyrate albumin-binding entities using multistep peptide-coupling chemistry. Both compounds were labeled with [ 225 Ac]Ac 3+ under mild conditions and their reversible binding to serum albumin was analyzed by an ultrafiltration assay as well as microscale thermophoresis measurements. Saturation binding studies and clonogenic survival assays using PSMA-expressing LNCaP cells were performed to evaluate PSMA-mediated cell binding and to assess the cytotoxic potency of the novel radioconjugates [ 225 Ac]Ac-mcp-M-alb-PSMA and [ 225 Ac]Ac-mcp-D-alb-PSMA, respectively. Biodistributions of both 225 Ac-radioconjugates were investigated using LNCaP tumor-bearing SCID mice. Histological examinations of selected organs were performed to analyze the occurrence of necrosis using H&E staining, DNA damage via γH2AX staining and proliferation via Ki67 expression in the tissue samples. Results: Enhanced binding to serum components in general and to human serum albumin in particular was revealed for [ 225 Ac]Ac-mcp-M-alb-PSMA and [ 225 Ac]Ac-mcp-D-alb-PSMA, respectively. Moreover, the novel derivatives are highly potent PSMA ligands as their KD values in the nanomolar range (23.38 and 11.56 nM) are comparable to the reference radioconjugates [ 225 Ac]Ac-mcp-M-PSMA (30.83 nM) and [ 225 Ac]Ac-mcp-D-PSMA (10.20 nM) without albumin binders. The clonogenic activity of LNCaP cells after treatment with the 225 Ac-labeled ligands was affected in a dose-and time-dependent manner, whereas the bivalent radioconjugate [ 225 Ac]Ac-mcp-D-alb-PSMA has a stronger impact on the clonogenic cell survival than its monovalent counterpart [ 225 Ac]Ac-mcp-M-alb-PSMA. Biodistribution studies performed in LNCaP tumor xenografts showed prolonged blood circulation times for both albumin-binding radioconjugates and a substantially increased tumor uptake (46.04 ± 7.77 %ID/g for [ 225 Ac]Ac-mcp-M-alb-PSMA at 128 h p.i. and 153.48 ± 37.76 %ID/g at 168 h p.i. for [ 225 Ac]Ac-mcp-D-alb-PSMA) with favorable tumor-to-background ratios. Consequently, a clear histological indication of DNA damage was discovered in the tumor tissues, whereas DNA double-strand break formation in kidney and liver sections was less pronounced. Conclusion: The modification of the PSMA-based 225 Ac-radioconjugates with one or two albumin-binding entities resulted in an improved radioph...