Journal: bioRxiv
Article Title: Non-Genetic Mechanisms of Fractional Resistance to Abemaciclib in Dedifferentiated Liposarcoma
doi: 10.64898/2026.05.22.727236
Figure Lengend Snippet: (A) Experimental workflow of the operating room-to-lab pipeline used for single-cell, multiplexed immunofluorescence profiling. Lipo246 cells were cultured and dedifferentiated primary tumor cells were resected and dissociated to be treated with increasing concentrations of abemaciclib for 24 h. Cells were fixed and subjected to iterative indirect immunofluorescence imaging (4i) consisting of iteration of antibody labeling (block → 1°/2° Ab → elution) and imaging. Images from all 4i rounds are processed through a computational pipeline to perform single-cell segmentation, signal quantification, and feature extraction. (B) Lipo246 and primary tumor cells were stained for 17 cell cycle regulators pRB, RB, Ki-67, CDK2, CDK4, cyclin D1 (cycD1), cyclin E1 (cycE1), Cdt1, E2F1, cyclin A2 (cycA2), cyclin B1 (cycB1), p21, Mdm2, pS6, S6, p53, p16, and integrated DNA. Representative immunofluorescence images from sequential rounds of 4i demonstrate a subset of these regulators for repeated labeling of distinct protein targets within the same cells. Nuclear DNA staining is used for segmentation, image registration, and integration across imaging rounds. (C) Single-cell matrix of 4i-measured cell cycle features. Heatmap of normalized protein expression across all quantified regulators, with individual cells ordered by increasing ratio of phosphorylated to total RB (pRB/RB), computed from 4i measurements. The corresponding single-cell pRB/RB distribution is shown at right and exhibits a bimodal structure used to define low pRB/RB (blue; nonproliferating) and high pRB/RB (pink; proliferating) cell populations. This organization reveals coordinated variation in cell cycle regulators across the pRB/RB-defined axis of cell cycle state.
Article Snippet: To evaluate sensitivity to combined CDK4/6 and CDK2 inhibition, Lipo246 cells were cotreated with abemaciclib (Selleckchem, catalog no. S5716) and the CDK2 inhibitor tagtociclib (MedChem Express, catalog no. HY-137894A).
Techniques: Single Cell, Immunofluorescence, Cell Culture, Imaging, Antibody Labeling, Blocking Assay, Extraction, Staining, Labeling, Expressing