Maiocchi, S. | bioRxiv Science

bioRxiv2024

Drug-repurposing screen identifies thiostrepton as a novel regulator of the tumor suppressor DAB2IP

The tumor suppressor DAB2IP, a RasGAP and cytoplasmic adaptor protein, modulates signal transduction in response to several extracellular stimuli, negatively regulating multiple oncogenic pathways. Accordingly, the loss of DAB2IP in tumor cells fosters metastasis and enhances chemo- and radio-resistance. DAB2IP is rarely mutated in cancer but is frequently downregulated or inactivated by multiple mechanisms. Solid experimental evidence show that DAB2IP reactivation can reduce cancer aggressiveness in tumors driven by multiple different oncogenic mutations, making this protein an interesting target for anti-cancer therapy. Based on these premises, we screened a library of FDA-approved drugs to search for molecules that can increase DAB2IP protein levels. We exploited CRISPR/Cas9 gene editing to generate two prostate cancer cell models in which endogenous DAB2IP is fused to HiBiT, a peptide tag that enables luminescence-based detection of protein levels in a sensitive and quantitative manner. Using this approach, we identified drugs able to increase DAB2IP levels. We focus our attention on thiostrepton, a natural cyclic oligopeptide antibiotic that has been reported to inhibit survival of various cancer cell lines. Functional experiments revealed that the cancer inhibitory effect of thiostrepton is reduced in the absence of DAB2IP, suggesting that the observed upregulation contributes to its action. These findings encourage the further development of thiostrepton for the treatment of solid cancers, and unveil a novel molecular mechanism underlying its anti-tumoral action.

cancer biology↗

bioRxiv2020

Light Sheet Fluorescence Microscopy as a New Method for Unbiased Three-Dimensional Analysis of Vascular Injury

AimsAssessment of preclinical models of vascular disease are paramount in the successful translation of novel treatments. The results of these models have traditionally relied on 2-D histological methodologies. Light sheet fluorescence microscopy (LSFM) is an imaging platform that allows for 3-D visualization of whole organs and tissues. In this study, we describe an improved methodological approach utilizing LSFM for imaging of preclinical vascular injury models while minimizing analysis bias. Methods and ResultsThe rat carotid artery segmental pressure-controlled balloon injury and mouse carotid artery ligation injury were performed. Arteries were harvested and processed for LSFM imaging and 3-D analysis, as well as for 2-D area histological analysis. Artery processing for LSFM imaging did not induce vessel shrinkage or expansion, and was reversible by rehydrating the artery, allowing for subsequent sectioning and histological staining a posteriori. By generating a volumetric visualization along the length of the arteries, LSFM imaging provided different analysis modalities including volumetric, area, and radial parameters. Thus, LSFM-imaged arteries provided more precise measurements compared to classic histological analysis. Furthermore, LSFM provided additional information as compared to 2-D analysis in demonstrating remodeling of the arterial media in regions of hyperplasia and periadventitial neovascularization around the ligated mouse artery. ConclusionsLSFM provides a novel and robust 3-D imaging platform for visualizing and quantifying arterial injury in preclinical models. When compared with classic histology, LSFM outperformed traditional methods in precision and quantitative capabilities. LSFM allows for more comprehensive quantitation as compared to traditional histological methodologies, while minimizing user bias associated with area analysis of alternating, 2-D histological artery cross-sections. Translational PerspectiveA more reproducible and robust quantitation of vascular pathology in preclinical models is necessary to accelerate translational discovery. Current methodology to assess vascular disease has significant limitations. The methodology described herein employs a modern imaging modality, light sheet fluorescence microscopy (LSFM), to improve assessment of established preclinical vascular injury models. LSFM provides more comprehensive and precise analysis capabilities than classical histological approaches. Hence, LSFM applied to vascular research has the potential to drive new basic discoveries, and ultimately translation of novel therapies.

pathology↗