Prabhu, V. V. | bioRxiv Science

bioRxiv2024

Imipridones inhibit tumor growth and improve survival in an orthotopic liver metastasis mouse model of human uveal melanoma

PurposeUveal melanoma (UM) is a highly aggressive disease with very few treatment options. We previously demonstrated that mUM is characterized by high oxidative phosphorylation (OXPHOS). Here we tested the anti-tumor, signaling and metabolic effects of imipridones, CLPP activators which reduce OXPHOS indirectly and have demonstrated safety in patients. Experimental DesignWe assessed CLPP expression in UM patient samples. We tested the effects of imipridones (ONC201, ONC212) on the growth, survival, signaling and metabolism of UM cell lines in vitro, and for therapeutic effects in vivo in UM liver metastasis models. ResultsCLPP expression was confirmed in primary and mUM patient samples. ONC201/212 treatment of UM cell lines in vitro decreased OXPHOS effectors, inhibited cell growth and migration, and induced apoptosis. ONC212 increased metabolic stress and apoptotic pathways, inhibited amino acid metabolism, and induced cell death-related lipids. ONC212 also decreased tumor burden and increased survival in vivo in two UM liver metastasis models. ConclusionImipridones are a promising strategy for further testing and development in mUM.

cancer biology↗

bioRxiv2019

CofActor: A light and redox-gated optogenetic clustering tool to study abnormal cytoskeletal dynamics in stressed cells

The biochemical hallmarks of neurodegenerative diseases (neural fibrils, clumps, and tangles; heightened reactive oxygen species (ROS); cofilin-actin rods) have presented numerous challenges for development of in vivo diagnostic tools (1-7). Biomarkers such as amyloid beta (A{beta}) fibrils and Tau tangles in Alzheimers Disease (AD) are only accessible via invasive cerebrospinal fluid assay for peptide mass fingerprinting or post-mortem diagnosis (8-11), while ROS can be fleeting and thus challenging to monitor in vivo (12-15). While remaining a challenge for in vivo detection, the unique protein-protein interactions underlying these disease-specific biomarkers also present rich opportunities for the engineering of in vitro pathology-sensitive biosensors and bioactuators. These tools can be useful for the investigation of critical, early stage events in neurodegenerative diseases in both cellular and animal models (16, 17), while potentially leading to advanced detection reagents with clinical applications. In this report, we describe a light and redox-gated protein switch inspired by the phenomenon of cofilin-actin rod formation, which occurs in stressed neurons in the AD brain and following brain ischemia (18). By coupling the redox-sensitive interaction of cofilin and actin with the light responsive Cry2-CIB blue light switch, we accomplish both light- and ROS-gated control of this interaction. The resulting switch is referred to as the "CofActor" system. Site-directed mutagenesis of both cofilin and actin partners demonstrate which residues are critical for sustaining or abrogating the light and redox gated response. Furthermore, switch response varies depending on whether oxidative stress is generated via glycolytic inhibition or a combination of glycolytic inhibition and azide-induced oxidative stress. Finally, light and redox gated switch function was demonstrated in cultured hippocampal neurons. As a dual input biosensor, CofActor holds promise for the tracking of early stage events in neurodegeneration and the investigation of actin-binding protein interactions under oxidative stress.

neuroscience↗