Metastasis is the leading cause of cancer-related deaths of breast cancer patients. Some cancer cells in a tumour go through successive steps, referred to as the metastatic cascade, and give rise to m Show more
Metastasis is the leading cause of cancer-related deaths of breast cancer patients. Some cancer cells in a tumour go through successive steps, referred to as the metastatic cascade, and give rise to metastases at a distant site. We know that the plasticity and heterogeneity of cancer cells play critical roles in metastasis but the precise underlying molecular mechanisms remain elusive. Here we aimed to identify molecular mechanisms of metastasis during colonization, one of the most important yet poorly understood steps of the cascade. We performed single-cell RNA-Seq (scRNA-Seq) on tumours and matched lung macrometastases of patient-derived xenografts of breast cancer. After correcting for confounding factors such as the cell cycle and the percentage of detected genes (PDG), we identified cells in three states in both tumours and metastases. Gene-set enrichment analysis revealed biological processes specific to proliferation and invasion in two states. Our findings suggest that these states are a balance between epithelial-to-mesenchymal (EMT) and mesenchymal-to-epithelial transitions (MET) traits that results in so-called partial EMT phenotypes. Analysis of the top differentially expressed genes (DEGs) between these cell states revealed a common set of partial EMT transcription factors (TFs) controlling gene expression, including ZNF750, OVOL2, TP63, TFAP2C and HEY2. Our data suggest that the TFs related to EMT delineate different cell states in tumours and metastases. The results highlight the marked interpatient heterogeneity of breast cancer but identify common features of single cells from five models of metastatic breast cancer. Show less
The allochimeric MHC class I molecule [alpha1h1/u]-RT1.Aa that contains donor-type (Wistar Furth, WF; RT1u) epitopes displayed on recipient-type (ACI, RT1a) administered in conjunction with sub-therap Show more
The allochimeric MHC class I molecule [alpha1h1/u]-RT1.Aa that contains donor-type (Wistar Furth, WF; RT1u) epitopes displayed on recipient-type (ACI, RT1a) administered in conjunction with sub-therapeutic dose of cyclosporine (CsA) induces indefinite survival of heterotopic cardiac allografts in rat model. In vascularized transplantation models, the spleen contributes to graft rejection by generating alloantigen reactive T cells. The immune response in allograft rejection involves a cascade of molecular events leading to the formation of immunological synapses between T cells and the antigen-presenting cells. To elucidate the molecular pathways involved in the immunosuppressive function of allochimeric molecule we performed microarray and quantitative RTPCR analyses of gene expression profile of splenic T cells from untreated, CsA treated, and allochimeric molecule + subtherapeutic dose of CsA treated animals at day 1, 3 and 7 of post transplantation. Allochimeric molecule treatment caused down regulation of genes involved in actin filament polymerization (RhoA and Rac1), cell adhesion (Catna1, Vcam and CD9), vacuolar transport (RhoB, Cln8 and ATP6v1b2), and MAPK pathway (Spred1 and Dusp6) involved in tubulin cytoskeleton reorganization and interaction between actin and microtubule cytoskeleton. All these genes are involved in T cell polarity and motility, i.e., their ability to move, scan and to form functional immunological synapse with antigen presenting cells (APCs). These results indicate that the immunosuppressive function of allochimeric molecule may depend on the impairment of T cells' movement and scanning ability, and possibly also the formation of immunological synapse. We believe that these novel findings may have important clinical implications for organ transplantation. Show less