Comparative molecular genomic analyses of a spontaneous rhesus macaque model of mismatch repair-deficient colorectal cancer.
Nejla Ozirmak LermiStanton B GrayCharles M BowenLaura Reyes-UribeBeth K DrayNan DengRonald Alan HarrisMuthuswamy RaveendranFernando BenavidesCarolyn L HodoMelissa W TaggartKaren Colbert MaressoKrishna M SinhaJeffrey RogersEduardo VilarPublished in: PLoS genetics (2022)
Colorectal cancer (CRC) remains the third most common cancer in the US with 15% of cases displaying Microsatellite Instability (MSI) secondary to Lynch Syndrome (LS) or somatic hypermethylation of the MLH1 promoter. A cohort of rhesus macaques from our institution developed spontaneous mismatch repair deficient (MMRd) CRC with a notable fraction harboring a pathogenic germline mutation in MLH1 (c.1029C<G, p.Tyr343Ter). Our study aimed to provide a detailed molecular characterization of rhesus CRC for cross-comparison with human MMRd CRC. We performed PCR-based MSI testing (n = 41), transcriptomics analysis (n = 35), reduced-representation bisulfite sequencing (RRBS) (n = 28), and MLH1 DNA methylation (n = 10) using next-generation sequencing (NGS) of rhesus CRC. Systems biology tools were used to perform gene set enrichment analysis (GSEA) for pathway discovery, consensus molecular subtyping (CMS), and somatic mutation profiling. Overall, the majority of rhesus tumors displayed high levels of MSI (MSI-H) and differential gene expression profiles that were consistent with known deregulated pathways in human CRC. DNA methylation analysis exposed differentially methylated patterns among MSI-H, MSI-L (MSI-low)/MSS (MS-stable) and LS tumors with MLH1 predominantly inactivated among sporadic MSI-H CRCs. The findings from this study support the use of rhesus macaques as an alternative animal model to mice to study carcinogenesis, develop immunotherapies and vaccines, and implement chemoprevention approaches relevant to sporadic MSI-H and LS CRC in humans.
Keyphrases
- dna methylation
- copy number
- genome wide
- endothelial cells
- gene expression
- single cell
- mass spectrometry
- multiple sclerosis
- high throughput
- type diabetes
- oxidative stress
- squamous cell carcinoma
- small molecule
- late onset
- metabolic syndrome
- induced pluripotent stem cells
- pluripotent stem cells
- african american
- squamous cell
- genetic diversity