RT Journal Article
SR Electronic
T1 2022-RA-1499-ESGO Differential response of in-vitro mismatch repair-deficient hypermethylated endometrioid endometrial cancer models to DNA-hypomethylating agents
JF International Journal of Gynecologic Cancer
JO Int J Gynecol Cancer
FD BMJ Publishing Group Ltd
SP A154
OP A154
DO 10.1136/ijgc-2022-ESGO.329
VO 32
IS Suppl 2
A1 Louis El Khoury
A1 Wan Hsin Lin
A1 James Smadbeck
A1 Dorsay Sadeghian
A1 John Cheville
A1 Faye Harris
A1 Lindsey Kinsella
A1 Marina Walther Antonio
A1 Giuseppe Cucinella
A1 Gabriella Schivardi
A1 Alexa McCune
A1 Giannoula Karagouga
A1 Aaron Mansfield
A1 Andrea Mariani
A1 George Vasmatzis
A1 Panos Anastasiadis
A1 John Weroha
A1 Alyssa Larish
YR 2022
UL http://ijgc.bmj.com/content/32/Suppl_2/A154.1.abstract
AB Introduction/Background We sought to compare in-vitro mismatch-repair deficient endometrial cancer (EC) methylation and responses to DNA-hypomethylating agents using spheroid-based microcancer 3D tumor cell viability assay.Methodology Study tumor was prospectively collected from a patient with stage 1B, grade 2 endometrioid EC. Characterization entailed whole exome, RNA, and MatePair analysis. Somatic mutations, structural variants and transcriptomic profiling were used to identify potential driver pathways for inhibition. Epigenomic profiling was completed with Assay for Transposase-Accessible Chromatin and DNA-methylation with Reduced Representation Bisulfate Sequencing. A comparative hyper-duplicated, p53-mutated EC underwent identical testing. 3D microcancers of these tumors were subjected to DNA-methyltransferase (DNMT) inhibition. Cell viability was determined by CellTiter-Glow Luminescent Assay. Data transformation and dose-response curves were generated by GraphPad Prism using four-parameter logistic regression. Inhibitory effect (IE) was defined as percent reduction ATP from baseline at maximum plasma concentration (Cmax).Results Genomic sequencing revealed evidence of microsatellite instability with POLE variant of unknown significance. Global and promoter hypermethylation was observed in sample with fewer copy number variation. When contrasted with comparison tumor, we observed significant (p < 0.01), albeit modest, global (Δβ = 0.51) and promoter (Δβ = 0.52) hypermethylation. Methylation of both MLH1 and PMS2 was observed. While both gene bodies were hypermethylated (Δβ = 0.50 and Δβ = 0.15 respectively), only MLH1 was statistically different. Despite the lack of methylation of promoters for both genes, we noticed a gene expression fold reduction of 2.58 (MLH1) and 1.81 (PMS2). Inhibition of viability in both study and comparison was minimal by decitabine, shown by IE of 0 and 17.939, respectively. Conversely, IE of study tumor by azacitidine was more pronounced at 72.662, compared with 40.951 (figure 1).Abstract 2022-RA-1499-ESGO Figure 1 Normalized drug responses of study tumor (pink) and comparison tumor (blue) to azacitidine and decitabine. Dose-response curves of treatment were titrated for each agent across maximum inhibitory plasma concentration (black dotted line). Pink and blue dotted lines represent results of previous testingConclusion In MMR-D EC with MLH-1 hypermethylation, in-vitro tumor response to DNMT inhibition is superior for DNA/RNA incorporating azacitidine when compared to DNA-only incorporating decitabine.