Figure 6 from NXP800 Activates the Unfolded Protein Response, Altering AR and E2F Function to Impact Castration-Resistant Prostate Cancer Growth
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posted on 2025-03-17, 07:22 authored by Jonathan Welti, Denisa Bogdan, Ines Figueiredo, Ilsa Coleman, Juan Jiménez Vacas, Kate Liodaki, Franziska Weigl, Lorenzo Buroni, Wanting Zeng, Ilona Bernett, Claudia Bertan, Theodoros I. Roumeliotis, Amandeep Bhamra, Jan Rekowski, Bora Gurel, Antje J. Neeb, Jian Ning, Dapei Li, Veronica S. Gil, Ruth Riisnaes, Susana Miranda, Mateus Crespo, Ana Ferreira, Nina Tunariu, Elisa Pasqua, Nicola Chessum, Matthew Cheeseman, Robert te Poele, Marissa Powers, Suzanne Carreira, Jyoti Choudhary, Paul Clarke, Udai Banerji, Amanda Swain, Keith Jones, Wei Yuan, Paul Workman, Peter S. Nelson, Johann S. de Bono, Adam Sharp<p>NXP800 activates the UPR and inhibits E2F-mediated transcription to drive antitumor activity against the castration-resistant VCaP prostate cancer cell line–derived mouse xenograft. <b>A</b> and <b>B,</b> Castration-resistant emergent VCaP prostate cancer cell line–derived mouse xenografts were treated with vehicle (<i>n</i> = 7, gray) or 35 mg/kg NXP800 (active, <i>n</i> = 8, red) after tumors had established castration-resistant growth with a defined dosing schedule for 38 days. Mean tumor volume (normalized to start; defined as 100%) with SEM is shown. <i>P</i> values were calculated for NXP800 compared with vehicle using the unpaired Student <i>t</i> test at 38 days. <i>P</i> values ≤ 0.05 are shown (*; <b>A</b>). Time to reach 200% starting tumor volume was used as a surrogate endpoint for survival. HR with 95% CI and <i>P</i> value for univariate Cox survival model are shown (<b>B</b>). <b>C–G,</b> Castration-resistant VCaP prostate cancer cell line–derived mouse xenografts were treated with vehicle (<i>n</i> = 4) or 35 mg/kg NXP800 (active, <i>n</i> = 4) daily after tumors had established castration-resistant growth for 5 days with tumor collection 6 hours after final dose for pharmacodynamic studies. RNA-seq was performed on tumor samples. Analysis of RNA-seq with gene set enrichment analysis shows the enrichment and de-enrichment of Hallmark pathways comparing NXP800 (active) and vehicle. NES and FDR are shown as volcano plots. Colored dots denote significantly (FDR 0.05) enriched (red dots) and de-enriched (blue dots) pathways (<b>C</b>). Log<sub>2</sub> fold expression level changes of “activating” <i>E2F</i> (<i>E2F1</i>–<i>3</i>) family members treated with NXP800 (active) were compared with vehicle. <i>P</i> values were calculated by DESeq2 using the Wald test. <i>P</i> values ≤ 0.05 are shown (*; <b>D</b>). PERK, phospho-eIF2α, total-eIF2α, and ATF4 (PERK arm); ATF6 (ATF6 arm); IRE1 (IRE1 arm); and GAPDH (housekeeping) protein expression was determined by Western blot (<b>E</b>). Cleaved caspase 3 (<b>F</b>) and Ki-67 (<b>G</b>) protein expression was determined by IHC on formalin-fixed, paraffin-embedded tumors. Representative micrographs are shown. Scale bar, 50 μm. Mean percentage positive cells with SD are shown. <i>P</i> values were calculated for NXP800 (red) compared with vehicle (white) using the unpaired Student <i>t</i> test. <i>P</i> values ≤ 0.05 are shown (*).</p>
