Abstract 1993: Off-target effects of ultra-low dose dimethyl sulfoxide on targetable signaling events in lung cancer in vitro models

Abstract

Abstract Background: The identification of targetable alterations in cancer continues to offer novel opportunities to the drug discovery process. However, pre-clinical testing often requires solubilization of these drugs in cosolvents like dimethyl sulfoxide (DMSO). Using commercially available models commonly used for in vitro drug screening and pre-clinical testing, we explored the DMSO off-target effects on functional signaling networks, drug targets, and downstream substrates. Materials and Methods: Eight commercially available Non-Small Cell Lung Cancer (NSCLC) cell lines were incubated with three ultra-low concentrations of DMSO (0.0008%, 0.002%, and 0.004% v/v, respectively) for 5 min, as well as 1, 6 and 24 hours. Following incubation, expression and activation levels of 183 proteins were captured using Reverse Phase Protein Array (RPPA) technology, of which 134 were kinases and downstream substrates. Results: The DMSO effect was heterogenous across cell lines and varied based on multiple factors including: concentration, exposure time, and cell line. Of the 183 proteins measured, 88% were statistically significant at the highest DMSO concentration, followed by 81% and 67% at lower concentrations. Only 28 proteins were found statistically different in more than 5 cell lines indicating heterogenous response across models. pERK 1/2 T202/Y204 emerged as the most frequently affected node along with stress-induced response and mitogenic proteins. These cell line specific DMSO-induced alterations, may modulate response to targeted agents and chemotherapeutics. Conclusions: Ultra-low DMSO concentrations have broad and heterogenous effects on targetable signaling proteins which are model, time, and concentration dependent. As such, off-target effects need to be carefully evaluated in the design and implementation of pre-clinical drug screening and testing. Citation Format: Elisa Baldelli, Mahalakshmi Subramanian, Abduljalil M. Alsubaie, Sara Baglivo, K A. Hodge, Fortunato Bianconi, Vienna Ludovini, Lucio Crino', Emanuel F. Petricoin, Mariaelena Pierobon. Off-target effects of ultra-low dose dimethyl sulfoxide on targetable signaling events in lung cancer in vitro models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1993.