Characterization of necroptosis activators in colorectal cancer.

Abstract

3522 Background: Necroptosis is a pro-inflammatory form of programmed cell death triggered by cellular stresses and extrinsic cytokines. It is a potential therapeutic target for immunotherapy (IO) in colorectal cancer (CRC). Here, we present comprehensive clinical and molecular characterization of key necroptosis regulators in CRC. Methods: 24,257 samples of CRC tested at Caris Life Sciences (Phoenix, AZ) with WTS (Illumina NovaSeq), NextGen DNA sequencing (NextSeq, 592 Genes and NovaSEQ, WES), and PD-L1 expression (22C3 clone; TPS ≥1%) were analyzed. Expression of activators in the necroptosis pathway ( RIPK3, MLKL, CYLD, and ZBP1) was categorized as either high (H) or low (L) using median expression as the cutoff. CRCs with high expression of all four activators were considered to have high propensity for necroptosis activity (NA-H, N=4595) compared to tumors with low expression in all activators (NA-L, N = 4946). RNA deconvolution analysis with QuantiSEQ estimated immune cell infiltration in the tumor microenvironment (TME). Differences in overall survival (OS) were analyzed from insurance claims data and calculated from treatment initiation using Kaplan-Meier estimates. Statistical significance was set as a P-value adjusted for multiple comparisons ( q<0.05). Results: NA-H was associated with increased PD-L1 positivity (4.0% vs 2.3%), immune cell infiltration, and T-cell inflamed score (all q<0.001). TP53 mutations were more frequent in NA-H, while SMAD2, SMAD4, KRAS, and NRAS mutations were associated with NA-L (all q<0.01). NA-H was associated with activation of KRAS signaling, allograft rejection, inflammatory/interferon gamma response, and pancreatic beta cell function pathways (all q<0.05). NA-H showed significantly improved OS in FOLFOX/FOLFIRI (F/F) (NA-L: 34.3 vs NA-H: 39.6 months [mo], P < 0.001; HR = 0.83, 95% CI 0.77 – 0.90) and those treated with IO (15.3 vs 22.4 mo, P = 0.018; HR = 0.77, 95% CI 0.62– 0.96) treated CRC patients. The benefit remained in TP53-mutated CRC treated with F/F (34.6 vs 41.0 mo, P < 0.001; HR = 0.82, 95% CI 0.74-0.90) and IO (10.0 vs 21.8 mo, P = 0.027; HR = 0.68, 95% CI 0.48-0.96) but not in the TP53-wild-type subgroup. Improved OS was observed with increased expression of CYLD and ZBP1(Table). The benefit remained in TP53-mutated CRC but not in the TP53 wildtype subgroup. Conclusions: This is the largest molecular and clinical characterization of necroptotic genes in CRC. Our data shows that activation of the necroptosis pathway is associated with immune cell infiltration/pathway activation, PD-L1 expression, and improved OS on F/F and IO. This benefit is more pronounced in TP53-mutated CRC, suggesting possible novel therapeutic targets.[Table: see text]