BackgroundProstate-specific membrane antigen (PSMA) is a promising target for diagnostics and therapy of prostate carcinoma (PCa). Based on the hypothesis that PSMA expression can be modulated by variations in androgen deprivation therapy (ADT), we investigated the binding of a PSMA-directed radiopharmaceutical in vitro in order to get an insight of the interactions between altered premedication and PSMA expression before repetitive PSMA-directed PET/CT for therapy response and targeted therapy implementation.MethodsThe human castration-resistant PCa cell line VCaP (CRPC) was treated with either 1 nmol/L testosterone (T) over 20 passages yielding the androgen-sensitive cell line (revCRPC) or with 5 μmol/L abiraterone acetate (AA) generating the abiraterone-tolerant subtype CRPCAA. In these cell lines, T and AA were varied by either supply or withdrawal of T and AA. PSMA expression of the three cell culture models was detected by Western blot and immunohistochemical staining. For quantitative measurement of tracer uptake, 0.3 nmol/L 68Ga-labelled PSMA-HBED-CC peptide (100–300 kBq/ml) was added to different treated parallel cultures (n = 9 each). Time-dependent uptake per 106 cells of each culture was calculated and evaluated. PSMA mRNA expression was investigated by qPCR.ResultsPSMA expression increased dependently on intensified ADT in all three basic cell lines. 68Ga-PSMA-HBED-CC uptake almost doubled during 3 h in all cell lines (p < 0.01). Compared to the basic cells, pre-incubation with abiraterone for 48 h resulted in a significant increased uptake in CRPC (p < 0.001). In revCRPC, 48-h AA pre-incubation resulted in an eightfold higher uptake after 3 h (p < 0.001). Additional withdrawal of external testosterone increased the uptake up to tenfold (p < 0.01). The increase of PSMA expression upon ADT and AA treatments was confirmed by qPCR and Western blot data. Furthermore, in CRPCAA, 48-h AA withdrawal increased the uptake up to fivefold (p < 0.01).ConclusionsThe investigated three PCa cell culture subtypes represent a serial preclinical model of androgen deprivation therapy as a proxy for clinical situations with differing basal PSMA expression. The uptake of PSMA-binding tracers could be stimulated by therapeutic effective short-term variation in premedication in all stages of ADT response. These complex interactions have to be considered in the interpretation of diagnostic imaging using PSMA ligands as well as in the optimal timing of PSMA-based therapies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-015-0145-8) contains supplementary material, which is available to authorized users.

Urachal cancer (UrC) is a rare but aggressive malignancy often diagnosed in advanced stages requiring systemic treatment. Although cytotoxic chemotherapy is of limited effectiveness, prospective clinical studies can hardly be conducted. Targeted therapeutic treatment approaches and potentially immunotherapy based on a biological rationale may provide an alternative strategy. We therefore subjected 70 urachal adenocarcinomas to targeted next-generation sequencing, conducted in situ and immunohistochemical analyses (including PD-L1 and DNA mismatch repair proteins [MMR]) and evaluated the microsatellite instability (MSI) status. The analytical findings were correlated with clinicopathological and outcome data and Kaplan-Meier and univariable/multivariable Cox regression analyses were performed. The patients had a mean age of 50 years, 66% were male and a 5-year overall survival (OS) of 58% and recurrence-free survival (RFS) of 45% was detected. Sequence variations were observed in TP53 (66%), KRAS (21%), BRAF (4%), PIK3CA (4%), FGFR1 (1%), MET (1%), NRAS (1%), and PDGFRA (1%). Gene amplifications were found in EGFR (5%), ERBB2 (2%), and MET (2%). We detected no evidence of MMR-deficiency (MMR-d)/MSI-high (MSI-h), whereas 10 of 63 cases (16%) expressed PD-L1. Therefore, anti-PD-1/PD-L1 immunotherapy approaches might be tested in UrC. Importantly, we found aberrations in intracellular signal transduction pathways (RAS/RAF/PI3K) in 31% of UrCs with potential implications for anti-EGFR therapy. Less frequent potentially actionable genetic alterations were additionally detected in ERBB2 (HER2), MET, FGFR1, and PDGFRA. The molecular profile strengthens the notion that UrC is a distinct entity on the genomic level with closer resemblance to colorectal than to bladder cancer.

The pathomechanisms underlying the development of thrombofibrotic pulmonary artery occlusions in Chronic Thromboembolic Pulmonary Hypertension (CTEPH) are largely unknown. The aim of this study was to allocate distinct cellular processes playing a role in thrombus resolution, such as inflammation, hypoxia, proliferation, apoptosis and angiogenesis, to different stages of thrombofibrotic remodelling. A total of 182 pulmonary endarterectomy (PEA) specimens were collected from 31 CTEPH patients. To facilitate co-localisation, Tissue MicroArrays were prepared and processed for (immuno)-histochemistry and confocal fluorescence microscopy. Murine venous thrombus formation and resolution was examined after inferior vena cava ligation. PEA tissues exhibited five morphologically distinct regions predominantly consisting of either fibrin-, erythrocyte- or extracellular matrix-rich thrombus, myofibroblasts, vessels or fibrotic tissue, and were found to resemble chronological stages of thrombus resolution in mice. Cellularity was highest in vessel-rich regions, and numerous cells were strongly positive for HIF1α or HIF2α as well as markers of activated VEGF signalling, including endothelial nitric oxide synthase. On the other hand, negative regulators of angiogenic growth factor signalling and reactive oxygen species were also highly expressed. Immune cells, primarily macrophages of the M2 subtype and CD117 haematopoietic progenitors were detected and highest in vascularised regions. Our findings demonstrate the simultaneous presence of different stages of thrombus organisation and suggest that hypoxia-induced endothelial, mesenchymal and immune cell activation may contribute to thrombofibrosis in CTEPH. This systematic histological characterisation of the material obstructing pulmonary vessels in CTEPH may provide a valuable basis for further studies aimed at determining causal factors underlying this disease.

demonstrate that CD24 can be transactivated by the pluripotency factor SOX2, which binds in proximity to the CD24 promoter. In GCTs, CD24 expression is controlled by epigenetic mechanisms, i.e. histone acetylation, since CD24 can be induced by the application histone deacetylase inhibitors. Vice versa, CD24 expression is downregulated upon inhibition of histone methyltransferases, E3-ubiquitin ligases or bromodomain (BRD) proteins. Additionally, three-dimensional (3D) co-cultivation of EC cells with microenvironmental cells, such as fibroblasts, endothelial or immune cells, reduced CD24 expression, suggesting that crosstalk with the somatic microenvironment influences CD24 expression. In a CRISPR/Cas9-deficiency model, we demonstrate that CD24 fulfils a bivalent role in differentiation via regulation of homeobox, phospho-and glycoproteins, i.e. it is involved in suppressing the germ cell/spermatogenesis program and mesodermal/endodermal differentiation, while poising the cells for ectodermal differentiation. Finally, blocking CD24 by a monoclonal antibody enhanced sensitivity towards cisplatin in EC cells, including cisplatin-resistant subclones, highlighting CD24 as a putative target in combination with cisplatin.

Patients with head‐and‐neck cancer can develop both lung metastasis and primary lung cancer during the course of their disease. Despite the clinical importance of discrimination, reliable diagnostic biomarkers are still lacking. Here, we have characterised a cohort of squamous cell lung (SQCLC) and head‐and‐neck (HNSCC) carcinomas by quantitative proteomics. In a training cohort, we quantified 4,957 proteins in 44 SQCLC and 30 HNSCC tumours. A total of 518 proteins were found to be differentially expressed between SQCLC and HNSCC, and some of these were identified as genetic dependencies in either of the two tumour types. Using supervised machine learning, we inferred a proteomic signature for the classification of squamous cell carcinomas as either SQCLC or HNSCC, with diagnostic accuracies of 90.5% and 86.8% in cross‐ and independent validations, respectively. Furthermore, application of this signature to a cohort of pulmonary squamous cell carcinomas of unknown origin leads to a significant prognostic separation. This study not only provides a diagnostic proteomic signature for classification of secondary lung tumours in HNSCC patients, but also represents a proteomic resource for HNSCC and SQCLC.