Expression of Nectin-4 in Variant Histologies of Bladder Cancer and Its Prognostic Value-Need for Biomarker Testing in High-Risk Patients?

Simple Summary Variant histologies of bladder cancer present at advanced stage and are often treated with radical cystectomy. As Nectin-4 appears to be a promising target for novel therapies in conventional bladder cancer, we aimed to analyze the expression of Nectin-4 and its prognostic value in variant histologies of bladder cancer. We found a high expression of Nectin-4 in squamous cell carcinoma and adenocarcinoma and a low expression in sarcomatoid urothelial carcinoma. No impact of Nectin-4 expression on survival has been detected in our study. Our study reveals the need to perform further biomarker testing for Nectin-4 in prospective trials including patients with variant histologies. Variant histologies of bladder cancer (BC) often present with advanced tumor stage and the status of perioperative therapy is unclear. Thereby, squamous cell carcinoma (SCC), adenocarcinoma (ADENO), and sarcomatoid urothelial carcinoma (SARCO) are the most frequent variants. Nectin-4 has emerged as a highly interesting target in BC and might guide therapeutic application of antibody-drug conjugates (ADC). We therefore aimed to investigate expression patterns and prognostic value of Nectin-4 in variant histologies of BC. A single-center retrospective analysis was conducted of patients who underwent radical cystectomy (RC) for BC and revealed variant histologies of BC in the final specimens. Immunohistochemical staining for Nectin-4 was performed on tissue microarrays with 59 SCC, 22 ADENO, and 24 SARCO, and Nectin-4 expression was scored using the histochemical scoring system (H-score). Overall survival (OS) and progression-free survival (PFS) was calculated by Kaplan-Meier method. Median expression of Nectin-4 was 150 (range 0-250) in SCC, 140.5 (range 30-275) in ADENO, and 10 (0-185) in SARCO, with significantly lower levels for SARCO compared to SCC or ADENO (p 0.05). Multivariate analysis revealed nodal stage as an independent prognostic factor for OS and PFS and metastases for PFS but not Nectin-4 expression. In conclusion, Nectin-4 was not prognostic in histological subtypes of BC in our study cohort. However, the high expression of Nectin-4 in SCC and ADENO might guide future treatment with novel Nectin-4-directed ADCs and provide this high-risk patient collective with a new promising therapeutic option. Testing Nectin-4 expression as a biomarker should be considered in trials with SARCO, where low Nectin-4 expression has been observed

Single-cell transcriptomic atlas-guided development of CAR-T cells for the treatment of acute myeloid leukemia

A single-cell screening approach identifies targets for CAR-T cells in acute myeloid leukemia. Chimeric antigen receptor T cells (CAR-T cells) have emerged as a powerful treatment option for individuals with B cell malignancies but have yet to achieve success in treating acute myeloid leukemia (AML) due to a lack of safe targets. Here we leveraged an atlas of publicly available RNA-sequencing data of over 500,000 single cells from 15 individuals with AML and tissue from 9 healthy individuals for prediction of target antigens that are expressed on malignant cells but lacking on healthy cells, including T cells. Aided by this high-resolution, single-cell expression approach, we computationally identify colony-stimulating factor 1 receptor and cluster of differentiation 86 as targets for CAR-T cell therapy in AML. Functional validation of these established CAR-T cells shows robust in vitro and in vivo efficacy in cell line- and human-derived AML models with minimal off-target toxicity toward relevant healthy human tissues. This provides a strong rationale for further clinical development

Targeting c-MYC through interference with NAMPT and SIRT1 and their association to oncogenic drivers in murine serrated intestinal tumorigenesis1

We recently described a positive feedback loop connecting c-MYC, NAMPT, DBC1 and SIRT1 that contributes to unrestricted cancer cell proliferation. Here we determine the relevance of the loop for serrated route intestinal tumorigenesis using genetically well-defined BrafV600E and K-rasG12D mouse models. In both models we show that c-MYC and SIRT1 protein expression increased through progression from hyperplasia to invasive carcinomas and metastases. It correlated with high NAMPT expression and was directly associated to activation of the oncogenic drivers. Assessing functional and molecular consequences of pharmacological interference with factors of the loop, we found that inhibition of NAMPT resulted in apoptosis and reduced clonogenic growth in human BRAF-mutant colorectal cancer cell lines and patient-derived tumoroids. Blocking SIRT1 activity was only effective when combined with a PI3K inhibitor, whereas the latter antagonized the effects of NAMPT inhibition. Interfering with the positive feedback loop was associated with down-regulation of c-MYC and temporary de-repression of TP53, explaining the anti-proliferative and pro-apoptotic effects. In conclusion we show that the c-MYC-NAMPT-DBC1-SIRT1 positive feedback loop contributes to murine serrated tumor progression. Targeting the feedback loop exerted a unique, dual therapeutic effect of oncoprotein inhibition and tumor suppressor activation. It may therefore represent a promissing target for serrated colorectal cancer, and presumably for other cancer types with deregulated c-MYC