Project description:During the metastatic process, most of the disseminated tumor cells fail to adapt to new tissue conditions upon arrival and die, resulting in a selection of the fittest cells. Among these hurdles, the immune system’s anti-tumor activity is one of the main barriers of metastatic colonization. Among the different Metastasis-initiating cells (MICs) properties, immune evasion stands out as one of the most necessary traits leading metastasis. The immune landscape of distant organs impose immune pressure on tumor cells engaging a process of tumor-immune coevolution and selection of immune-evasive tumor cells, in a process called cancer immunoediting. In this study, we aimed to investigate the altered gene patterns of breast cancer cells induced by the interaction with the immune system. Specifically, we were looking for phenotypes and immune-evasive behaviour of immunoedited cells leading the metastatic colonization.
Project description:Cancers evade the immune system in order to grow or metastasise through the process of cancer immunoediting. While checkpoint inhibitor therapy has been effective for reactivating tumour immunity in some cancers, many solid cancers, including breast cancer, remain largely non-responsive. Understanding the way non-responsive cancers evolve to evade immunity, what resistance pathways are activated and whether this occurs at the clonal level will improve immunotherapeutic design. We tracked cancer cell clones during the immunoediting process and determined clonal transcriptional profiles that allow immune evasion in murine mammary tumour growth in response to immunotherapy with anti-PD1 and anti-CTLA4. Clonal diversity was significantly restricted by immunotherapy treatment at both the primary and metastatic sites. These findings demonstrate that immunoediting selects for pre-existing breast cancer cell populations, that immunoediting is not a static process and is ongoing during metastasis and immunotherapy treatment. Isolation of immunotherapy resistant clones revealed unique and overlapping transcriptional signatures. The overlapping gene signature was predictive of poor survival in basal-like breast cancer patient cohorts. Some of these overlapping genes have existing small molecules which can be used to potentially improve immunotherapy response.
Project description:Metastatic cancer cells, originating from cancer stem cells with metastatic capacity, utilize nutrient flexibility to overcome the hurdles of metastatic cascade. However, the nutrient supply for maintaining the stemness potentials of metastatic cancer cells remains unknown. Here, we revealed that metastatic breast cancer cells maintain stemness and initiate metastasis upon detachment via uptaking and oxidating lactate. In detached metastasizing breast cancer cells, lactate was incorporated into tricarboxylic acid cycle and boosted oxidative phosphorylation, and then promoted the stemness potentials via α-KG-DNMT3B-mediated SOX2 hypomethylation. Moreover, lactate was uptake and oxidated in mitochondria by CD147/MCT1/LDHB complex, whose existence correlates to the stemness potentials and tumor metastasis in breast cancer patients. An intracellularly expressed single chain variable fragment targeting mitochondrial CD147 (mito-CD147 scFv) effectively disrupted mitochondrial CD147/MCT1/LDHB complex, inhibited lactate-induced stemness potentials, depleted circulating breast cancer cells and reduced metastatic burden, suggesting a promising clinical application in reducing lactate-fueled metastasis.
Project description:N-linked glycosylation results in a large branched tree-like sugar structure composed of several types of individual carbohydrates being attached to a protein. Fucosylation is one specific type of glycosylation that is defined by the addition of α-L-fucose to a carrier protein. Although fucosylation has been relatively well defined as a biomarker for progression in some human cancers, for example, pancreatic and hepatocellular carcinoma, its role in breast cancer is much less well defined. A growing body of evidence indicates that levels of fucosylation correlate with breast cancer progression and contributes to metastatic disease. However, very little is known about the signaling and functional outcomes that are driven by fucosylation. We performed tandem- mass-tag (TMT) proteomics on 4T1 metastatic mammary tumor cells that were treated with a fucosylation inhibitor, 2-fluorofucose (2FF) or vehicle (DMSO) control. This analysis identified >400 proteins that were significantly increased or decreased in 2FF treated samples compared to the DMSO treated samples. We found that two proteins, Tollip and Bcl-10, were downregulated in 4T1 cells in response to 2FF treatment. Functionally, Tollip and Bcl10 signaling induce pro-inflammatory responses through activation of NF-κB, a transcription factor that is pro-tumorigenic and a prime target in human cancer. Our results show that treatment of 4T1 cells with 2FF leads to a reduction in NF-κB expression and activity through increased IκBα. This observation is consistent with a reduction in inflammatory response due to the loss of Tollip and Bcl-10 expression. Collectively, our results indicate that fucosylation is a key mediator of inflammatory signaling in metastatic breast cancer cells.