Journal: Nature Communications

Article Title: BH3 mimetics targeting BCL-XL have efficacy in solid tumors with RB1 loss and replication stress

doi: 10.1038/s41467-025-60238-x

Figure Lengend Snippet: A Genomic characterization of PCa models based on PCa-commonly altered genes. B Validation of RB1-loss induced sensitivity to BCL-XL inhibitor using an independent PCa PDX-derived spheroid cohort. Upper panels: RB1 expression by IHC and H-scores. Lower panels: organoid cultures from each PDX were treated with navitoclax for 6 h and caspase activity was assessed (left), or treated for 4 days and cells viability was assessed (right). Mean and SEM for 5 biological replicates are shown. Data were analyzed by one-way ANOVA * p < 0.05 (left panel: p = 0.003 for model CP267C and p = 0.002 for model CP336C, right panel: p = 0.002 for model CP267C and p = 0.001 for model CP336C). Scale bar is 100 μM. C Comprehensive analysis of solid tumor cell lines sensitivity to BCL-XL inhibitors (Navitoclax, WEHI and ABT737) based on RB1 alteration (combined mutation or copy number loss). Data were analyzed by unpaired t -test. D Volcano plot with effect size ( x axis) and significance (y axis) of large-effect cancer-specific pharmacogenomic interactions based on RB1 alteration. Each circle represents an association between RB1 status and drug sensitivity analyzed using ANOVA (Genomics of Drug Sensitivity in Cancer- Sanger Institute/Mass General Cancer Center database). E Effect of short term RB1 silencing on BCL-XL sensitivity in LNCaP (RB1 proficient PCa cell line). Cells were treated with siRNA targeting RB1 (siRB1) or nontarget control (siNT) for 48 h. Navitoclax was then added to media for 6 h. Apoptotic effect was assessed by luminescence assay over a range of navitoclax concentrations (left panel) and apoptosis markers at 500 nM navitoclax by immunoblotting (right panel). Mean and SEM for 3 biological replicates are shown. Effects of RB1 siRNA at each navitoclax concentration were analyzed by unpaired t -test, * p < 0.05. Two-way ANOVA then showed that the effect of the shRNA on response to navitoclax was significant ( p = 0.002). F Effect of long-term RB1 silencing on BCL-XL sensitivity in LNCaP cells. Cells were infected with shRNA targeting RB1 (shRB1) or nontarget control (shNT) constructs and treated with increasing doses of enzalutamide until development of resistance to 5 μM. Left panel: RB1 expression in the enzalutamide adapted cells. Middle panel: apoptosis activity of cells treated with navitoclax for 6 h based on luminescence assay. Right panel: viability assay of cells treated with navitoclax for 4 days based on luminescence assay. Mean and SEM for 3 biological replicates are shown. Effects of RB1 shRNA at each Navitoclax concentration were analyzed by unpaired t -test, * p < 0.05. Two-way ANOVA then showed that the effect of the shRB1 on response to Navitoclax was significant ( p = 0.0001 for both apoptosis and viability analysis). Source data are provided as a Source Data file.

Article Snippet: Immunohistochemistry for RB1 was performed on various patient derived xenograft (PDX) passages [CP50C ( n = 3), CP253C ( n = 2), CP267C ( n = 1), CP336C ( n = 3)] using the mouse anti-RB1 monoclonal antibody (clone 4H1, Cell Signaling Technology, Massachusetts, USA).

Techniques: Biomarker Discovery, Derivative Assay, Expressing, Activity Assay, Mutagenesis, Control, Luminescence Assay, Western Blot, Concentration Assay, shRNA, Infection, Construct, Viability Assay

Journal: Nature Communications

Article Title: BH3 mimetics targeting BCL-XL have efficacy in solid tumors with RB1 loss and replication stress

doi: 10.1038/s41467-025-60238-x

Figure Lengend Snippet: A Mechanism of action drug screening to identify agents that synergize with navitoclax. LNCaP cells were cultured in navitoclax (500 nM) or DMSO containing media. Compounds from the ICCB-Longwood Mechanism of Action Library (ICCB-L MoA) were then added in duplicate at 4 concentrations were then added, and viability assay was performed after 48 h. This figure was created in Biorender. Yuan, X. (2025) https://BioRender.com/p38v199 B Left panel: average luminescence (viability) for cells cultured with library drug alone ( Y axis) versus with navitoclax (X-axis). Results for all 4 drug concentrations are plotted. Circles above blue lane represent potential positive hits. Right panel: drug class of positive hits. C Single sample gene set enrichment analysis of TCGA primary prostate cancer database was carried out. Activation of ATR Response to Replication Stress gene set was calculated for individual samples and plotted relative to RB1 copy number. Data were analyzed by one-way ANOVA * p < 0.05 ( p = 0.002). D LNCaP cells were treated with nolatrexed or vehicle for 48 h followed by navitoclax or vehicle for 4 days for cell recovery or 6 h for apoptosis. Left panel: cell cycle analysis of nolatrexed-treated LNCaP cells. Middle panel: cell recovery assessed by CTGlo assay. Right panel: caspase activation assessed by Caspase Glo 3/7 assay. Data are mean and SEM for biological replicates. Data at each nolatrexed concentration were analyzed by unpaired t -test, * p < 0.05. Two-way ANOVA then showed the effect of nolatrexed on response to navitoclax was significant ( p < 0.0001 for both apoptosis and viability analysis). Upper panel was created in Biorender. Yuan, X. (2025) https://BioRender.com/h91a470 E Analysis of apoptosis markers by immunoblotting of LNCaP cells treated with nolatrexed or vehicle for 2 days followed by navitoclax or vehicle for 6 h. F LNCaP cells were treated with nolatrexed alone or combined with thymidine for 2 days, followed by 6 h with navitoclax or vehicle, and apoptosis was assessed by CaspaseGlo 3/7 assay. Mean and SEM for 5 biological replicates are shown. Data at each nolatrexed concentration were analyzed by unpaired t -test, * p < 0.05. Two-way ANOVA then showed that the effect of adding thymidine was significant, p < 0.001. Source data are provided as a Source Data file.

Article Snippet: Immunohistochemistry for RB1 was performed on various patient derived xenograft (PDX) passages [CP50C ( n = 3), CP253C ( n = 2), CP267C ( n = 1), CP336C ( n = 3)] using the mouse anti-RB1 monoclonal antibody (clone 4H1, Cell Signaling Technology, Massachusetts, USA).

Techniques: Drug discovery, Cell Culture, Viability Assay, Activation Assay, Cell Recovery, Cell Cycle Assay, Caspase-Glo Assay, Concentration Assay, Western Blot