RNA-sequencing of gastric cancer PDX mice model after treated with CUS

The interaction between cancer and depressive disorder remains unclear. In this study, we obtained patient data from TCGA and MDD-related (Major Depressive Disorder) genes from the GEO database and the sequencing data of the PDX model with chronic unpredictable stress (CUS). Molecular subtypes and a prognostic signature were generated based on the MDD-related genes obtained by differential expression analysis. According to our analysis, the gene signature was a promising biomarker in distinguishing the prognosis, the molecular or immune characteristics, and the depressive risk, as well as the therapy candidates for gastric adenocarcinoma patients. To investigate the impact of depression on the expression of gastric cancer, we implanted surgical tissue fragments (obtained from a 77-year-old female gastric adenocarcinoma patient at Zhongnan Hospital of Wuhan University) into female NOD-SCID mice to establish a patient-derived xenograft (PDX) model. After three successive transplantations, the xenografts were isolated and implanted into the right axilla of BALB-c/nu female mice. Chronic unpredictable stress (CUS) was then applied to the PDX model for three weeks. Subsequently, gene expression profiling analysis was performed using data obtained from RNA-seq of three tumor tissues from PDX exposed to CUS and three tumor tissues from PDX not exposed to CUS.