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// Markus Eckstein 1, * , Ralph M. Wirtz 2, 3, * , Carolin Pfannstil 1, * , Sven Wach 4, * , Robert Stoehr 1, * , Johannes Breyer 6, * , Franziska Erlmeier 7, * , Cagatay Gunes 8, * , Katja Nitschke 5, * , Wilko Weichert 7, * , Wolfgang Otto 6, * , Bastian Keck 4, * , Sebastian Eidt 3, * , Maximilian Burger 6, * , Helge Taubert 4, * , Bernd Wullich 4, * , Christian Bolenz 8, * , Arndt Hartmann 1, * and Philipp Erben 5, * 1 Institute of Pathology, University of Erlangen-Nuremberg, Erlangen, Germany 2 STRATIFYER Molecular Pathology GmbH, Cologne, Germany 3 Institute of Pathology at The St. Elisabeth Hospital Koln-Hohenlind, Cologne, Germany 4 Department of Urology, University of Erlangen-Nuremberg, Erlangen, Germany 5 Department of Urology Mannheim, University of Heidelberg, Mannheim, Germany 6 Department of Urology, University of Regensburg, Regensburg, Germany 7 Institute of Pathology, Technical University Munich, Munich, Germany 8 Department of Urology, University of Ulm, Ulm, Germany * On behalf of the BRIDGE-Consortium Germany Correspondence to: Markus Eckstein, email: markus.eckstein@uk-erlangen.de Keywords: bladder cancer; PD-L1; checkpoint inhibitors; molecular therapy stratification; immunohistochemistry Received: October 26, 2017 Accepted: February 10, 2018 Epub: February 19, 2018 Published: March 13, 2018 ABSTRACT Background: Immunohistochemical PD-L1 assessment is currently used to identify responders towards checkpoint inhibitors although it is limited by inter-observer effects. Here, we conducted a multi-center round robin test to prove the possibility of assessing the PD-L1 status by gene expression to avoid inter-observer effects. Patients and methods: Gene expression of PD-L1 was analyzed in a total of 294 samples (14 cases non-muscle invasive and muscle-invasive bladder cancer; MIBC) in seven centers by a RT-qPCR kit and compared with immunohistochemical scoring of three pathologists (DAKO, 22c3). Both assays were compared towards prognosis prediction in a cohort of 88 patients with MIBC. Results: PD-L1 gene expression revealed very high inter center correlation (centrally extracted RNA: r = 0.68–0.98, p ≤ 0.0076; locally extracted RNA: r = 0.81–0.98, p ≤ 0.0014). IHC Inter-observer concordance was moderate to substantial for immune cells (IC), fair for combined IC/ tumor cell (TC) (IC: κ = 0.50–0.61; IC + TC: κ = 0.50), and fair for TC scoring (κ = 0.26–0.35). Gene expression assessment resulted in more positive cases (9/14 cases positive vs. 6/14 cases [IHC]) which could be validated in the independent cohort. Positive mRNA status was associated with significantly better overall and disease-specific survival (5-year OS: 50% vs. 26%, p = 0.0042, HR = 0.48; 5 year DSS: 65% vs. 40%, p = 0.012, HR = 0.49). The 1% IHC IC cut-off also revealed significant better OS (5 year OS: 58% vs. 31%, p = 0.036, HR = 0.62). Conclusion: Gene expression showed very high inter-center agreement. Gene expression assessment also resulted in more positive cases and revealed better prognosis prediction. PD-L1 mRNA expression seems to be a reproducible and robust tool for PD-L1 assessment.

// Elke Nolte 1 , Sven Wach 1 , Izabella Thais Silva 2, 6 , Sabine Lukat 1 , Arif B. Ekici 3 , Jennifer Munkert 4 , Frieder Muller-Uri 4 , Wolfgang Kreis 4 , Claudia Maria Oliveira Simoes 2 , Julio Vera 5 , Bernd Wullich 1 , Helge Taubert 1 , Xin Lai 5 1 Department of Urology, University Hospital Erlangen, Erlangen, Germany 2 Department of Pharmaceutical Sciences, Universidade Federal de Santa Catarina, Florianopolis, Brazil 3 Institute of Human Genetics, Friedrich-Alexander-Universitat Erlangen-Nurnberg, Erlangen, Germany 4 Department of Biology, Chair of Pharmaceutical Biology, Friedrich-Alexander-University Erlangen-Nurnberg, Erlangen, Germany 5 Laboratory of Systems Tumor Immunology, Department of Dermatology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nurnberg, Erlangen, Germany 6 Department of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, Brazil Correspondence to: Xin Lai, email: xin.lai@uk-erlangen.de Keywords: 3β-[2-(1-amantadine)-1-on-ethylamine]-digitoxigenin, cardiac glycoside analog, human renal cell carcinoma cells, miRNA, cell cycle Received: June 21, 2016 Accepted: December 24, 2016 Published: January 14, 2017 ABSTRACT Cardiac glycosides are well known in the treatment of cardiovascular diseases; however, their application as treatment option for cancer patients is under discussion. We showed that the cardiac glycoside digitoxin and its analog AMANTADIG can inhibit the growth of renal cell carcinoma (RCC) cell lines and increase G2/M cell cycle arrest. To identify the signaling pathways and molecular basis of this G2/M arrest, microRNAs were profiled using microRNA arrays. Cardiac glycoside treatment significantly deregulated two microRNAs, miR-2278 and miR-670-5p. Pathway enrichment analysis showed that all cardiac glycoside treatments affected the MAPK and the axon guidance pathway. Within these pathways, three genes, MAPK1, NRAS and RAC2, were identified as in silico targets of the deregulated miRNAs. MAPK1 and NRAS are known regulators of G2/M cell cycle arrest. AMANTADIG treatment enhanced the expression of phosphorylated MAPK1 in 786-O cells. Secondly, we studied the expression of survivin known to be affected by cardiac glycosides and to regulate the G2/M cell phase. AMANTADIG treatment upregulated the expression of the pro-apoptotic survivin-2B variant in Caki-1 and 786-O cells. Moreover, treatment with AMANTADIG resulted in significantly lower survivin protein expression compared to 786-O control cells. Summarizing, treatment with all cardiac glycosides induced G2/M cell cycle arrest and downregulated the miR-2278 and miR-670-5p in microarray analysis. All cardiac glycosides affected the MAPK-pathway and survivin expression, both associated with the G2/M phase. Because cells in the G2/M phase are radio- and chemotherapy sensitive, cardiac glycosides like AMANTADIG could potentially improve the efficacy of radio- and/or chemotherapy in RCCs.

The non-classical human leukocyte antigen E (HLA-E) expression is frequently overexpressed in tumor diseases, transplants and virus-infected cells and represents an immunomodulatory molecule by binding to the receptors CD94/NKG2A, -B and –C on NK and T cells. Due to its immune suppressive features HLA-E expression might represent an important mechanism of tumors to escape immune surveillance. While an aberrant expression of the non-classical HLA-G antigen in human renal cell carcinoma (RCC) has been demonstrated to be associated with a worse outcome of patients and reduced sensitivity to immune effector cell-mediated cytotoxicity, the expression and function of HLA-E has not yet been analyzed in this tumor entity. Higher levels of HLA-E transcripts were detected in all RCC cell lines and tumor lesions, which were tested in comparison to normal kidney epithelium. Immunohistochemical staining of a tissue microarray (TMA) using the HLA-E-specific monoclonal antibody TFL-033 recognizing the cytoplasmic HLA-E α-chain as monomer revealed a heterogeneous HLA-E expression in RCC lesions with the highest frequency in chromophobe RCC when compared to other RCC subtypes. HLA-E expression did not correlate with the frequency of CD3+, CD4+, CD8+ and FoxP3+ immune cell infiltrations, but showed an inverse correlation with infiltrating CD56+ cells. In contrast to HLA-G, HLA-E expression in RCCs was not statistically significant associated with a decreased disease specific survival. These data suggest that HLA-E overexpression frequently occurs in RCC and correlates with reduced immunogenicity.

The non-classical human leukocyte antigen G (HLA-G) is expressed at a high frequency in renal cell carcinoma (RCC) and is associated with a higher tumor grade and a poor clinical outcome. This might be caused by the HLA-G-mediated inhibition of the cytotoxicity of T and NK cells. Therefore a selective targeting of HLA-G might represent a powerful strategy to enhance the immunogenicity of RCC lesions. Recent studies identified a number of HLA-G-regulating microRNAs (miRs) and demonstrated an inverse expression of some of these miRs with HLA-G in RCC in vitro and in vivo. However, it was postulated that further miRs might exist contributing to the tightly controlled selective HLA-G expression. By application of a miR enrichment assay (miTRAP) in combination with in silico profiling two novel HLA-G-regulatory miRs, miR-548q and miR-628-5p, were identified. Direct interactions of both miRs with the 3′ untranslated region of HLA-G were confirmed with luciferase reporter gene assays. In addition, qPCR analyses and immunohistochemical staining revealed an inverse, expression of miR-628-5p, but not of miR-548q to the HLA-G protein in primary RCC lesions and cell lines. Stable overexpression of miR-548q and miR-628-5p caused a downregulation of HLA-G mRNA and protein. This leads in case of miR-548q to an enhanced NK cell-mediated HLA-G-dependent cytotoxicity, which could be reverted by ILT2 blockade suggesting a control of the immune effector cell activity at least by this miR. The identification of two novel HLA-G-regulatory miRs extends the number of HLA-G-relevant miRs tuning the HLA-G expression and might serve as future therapeutic targets.