Pluto Bioinformatics

GSE140192: Comparative profiling of metastatic 4T1- versus non-metastatic Py230-based mammary tumors in an intraductal model for triple-negative breast cancer.

Bulk RNA sequencing

Purpose: Compare the tumor outgrowth and immunology of an immunocompetent 4T1- and Py230-based intraductal model for triple-negative breast cancer (TNBC).; ; Methods: BALB/c-derived 4T1 and C57BL/6-derived Py230 mammary tumor cells were side-by-side intraductally inoculated in lactating and syngeneic mice, 4T1 and Py230 primary tumors were subsequently resected at 1, 3 and 6 weeks (w) post-inoculation (p.i.), and RNA was isolated from the 4T1 and Py230 primary tumors using in house developed protocols.; ; Results: The differentially expressed genes in the 4T1 versus Py230 primary tumor datasets at the 3 different time points were categorized into 28 hallmark gene sets using GSEA. Nine hallmarks could be related to tumor immunology and collectively showed a decreased difference in expression over time, although every immunology-related gene set remained most expressed in 4T1 primary tumors across all time points. Seven hallmarks could be related to cellular mitosis and tumor progression and were significantly upregulated at 1 w p.i. in 4T1 primary tumors, whereas at 3 w p.i. they became significantly upregulated in Py230 primary tumors, indicative for enhanced Py230 tumor proliferation. The hallmark epithelial-mesenchymal transition was significantly upregulated at 3 w p.i. in 4T1 compared to Py230 primary tumors, indicative for metastatic progression. Gene sets involved in adipose/stromal processes within the mammary gland were downregulated or weakly expressed at 1 w p.i., but became upregulated at 3 w p.i. in 4T1 compared to Py230 primary tumors, indicating that at the time 4T1 tumor cells were less proliferative compared to Py230 tumor cells, the surrounding stroma and fat tissue were more active in the 4T1- compared to the Py230-based intraductal model. The hallmark androgen response also showed a significantly upregulated expression in Py230 tumors at 3 and 6 w p.i., indicating that androgen signaling is important in invasive Py230 tumors.; ; Conclusion: Our findings highlight an innovative 4T1- and Py230-based intraductal mouse model for TNBC with a different tumor outgrowth and associated tumor microenvironment. These differential models may broadly represent the clinically observed TNBC diversity and together provide a powerful tool to evaluate therapeutics. SOURCE: Jonas Steenbrugge (jonas.steenbrugge@ugent.be) - Laboratory of Biochemistry Ghent University