Project description:Gpx1 plays a vital role in the metastasis of TNBC cells by regulating cell adhesion. Depletion of Gpx1 reduces the survival, migration, and invasion of TNBC cells in vitro. Transcriptomic and signaling pathway analyses demonstrate that depletion of Gpx1 essentially impairs cell adhesion/spreading by down-regulating FAK/c-Src activation.
Project description:Triple-Negative Breast Cancer (TNBC) has a poor prognosis and adverse clinical outcomes among all breast cancer subtypes as there is no available targeted therapy. Overexpression of Enhancer of zeste homolog 2 (EZH2) has been shown to correlate with TNBC's poor prognosis, but the contribution of EZH2 catalytic (H3K27me3) versus non-catalytic EZH2 (NC-EZH2) function in TNBC progression remains elusive. We reveal that selective hyper-activation of functional EZH2 (H3K27me3) over NC-EZH2 alters TNBC metastatic landscape and fosters its peritoneal metastasis, particularly splenic. Instead of H3K27me3-mediated repression of gene expression; here, it promotes KRT14 transcription by attenuating binding of repressor Sp1 to its promoter. Further, KRT14 loss significantly reduces TNBC migration, invasion, and peritoneal metastasis. Consistently, human TNBC metastasis displays positive correlation between H3K27me3 and KRT14 levels. Finally, EZH2 knockdown or H3K27me3 inhibition by EPZ6438 reduces TNBC peritoneal metastasis. Altogether, our preclinical findings suggest a rationale for targeting TNBC with EZH2 inhibitors.
Project description:CCL5/CCR5 axis is an immunotherapeutic target for triple-negative breast cancer (TNBC). However, the signaling mechanism is poorly understood and its antagonists have not been reported. Here, we developed a high-throughput screening (HTS) assay for discovering its antagonists. Verteporfin was identified as a specific and more potent inhibitor than maraviroc. It significantly reduced TNBC tumor growth in an immunologically dependent manner, and lung metastasis in a cell-intrinsic way. Mechanistically, CCR5 was co-expressed with Yes-associated protein 1 (YAP1) in TNBC patients. RNA-sequencing and expression silencing further revealed that CCR5 promoted the expression of YAP1 through HIF-1α in TNBC cells, and through YAP1 to regulate β-catenin, ZEB1/ZEB2 for metastasis, as well as CXCL16 and CXCL8 for immune cell migration and tumor growth. In essence, verteporfin may have potential immunotherapeutic applications for diseases co-expressing CCR5 and YAP1 such as TNBC. The HTS assay can be adapted for unveiling antagonists of broader signaling pathways.
Project description:We identified sphingosine kinase 1 (SPHK1) as a top candidate. SPHK1-overexpression in human TNBC cell-line promotes spontaneous metastasis to lungs in nude mice. Moreover, genetic knockdown of SPHK1 in TNBC patient-derived xenograft (PDX) cells and TNBC cell-line decreases spontaneous metastasis to lungs in nude mice. SPHK1 regulates the FSCN1 gene expression in order to drive metastasis. Mechanistically, SPHK1 transcriptionally upregulates metastasis-promoting FSCN1 gene expression via NFκB activation to promote metastasis. SPHK1/NFκB/FSCN1 signaling pathway activation is associated with distance metastasis and poor clinical outcome in TNBC patients.
Project description:Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that shows high infiltration of cancer stem cells (CSCs), which correlates with poor clinical outcome. Here, we have demonstrated that an aberrant activation of CDK5/pho-PPARg axis associated with TNBC progression closely. CDK5 blockade sufficiently abrogates stemness transformation of TNBC cells, resulting in a significant inhibition of tumor metastatic progression. Moreover, CDK5 inhibitor Rosc attenuates CD44v+ BCSCs, hereby reversing immunosuppressive microenvironment and enhancing anti-PD-1 effects on TNBC. Mechanistically, CDK5/pho-PPARgaxis modulates the ESRP1 degradation via E3 ligase-like activity, leading to CD44 variant (CD44v) expression. Our finding indicates that CDK5 blockade could be a potent strategy to target CSCs in TNBC, and to increase the response to PD-1 blockade in TNBC therapy.
Project description:Primary tumor growth and metastasis in triple-negative breast cancer (TNBC) require supporting vasculature, which develop through a combination of endothelial angiogenesis and vasculogenic mimicry (VM), a process associated with aggressive metastatic behavior in which vascular-like structures are lined by tumor cells. We developed αEGFR-E-P125A, an antibody-endostatin fusion protein that delivers a dimeric, mutant endostatin (E-P125A) payload that inhibits TNBC angiogenesis and VM in vitro and in vivo. To characterize the mechanisms associated with induction and inhibition of VM, RNA-seq of MDA-MB-231-4175 TNBC cells grown in a monolayer (2D) was compared to cells plated on Matrigel undergoing VM (3D). We then compared RNA-seq between TNBC cells in 3D and cells in 3D with VM inhibited by αEGFR-E-P125A (αEGFR-E-P125A). Gene set enrichment analysis (GSEA) demonstrated that VM induction activated the IL6-JAK-STAT3 and angiogenesis pathways, which were downregulated by αEGFR-E-P125A treatment. Correlative analysis of the phospho-proteome demonstrated decreased EGFR phosphorylation at Y1069, along with decreased phosphorylation of focal adhesion kinase (FAK) Y397 and STAT3 Y705 sites downstream of α5β1 integrin. Suppression of phosphorylation events downstream of EGFR and α5β1 integrin demonstrated that αEGFR-E-P125A interferes with ligand-receptor activation, inhibits VM, and overcomes oncogenic signaling associated with EGFR and α5β1 integrin crosstalk. In vivo, αEGFR-E-P125A treatment decreased primary tumor growth and VM, reduced lung metastasis, and confirmed the inhibition of signaling events observed in vitro. Simultaneous inhibition of EGFR and α5β1 integrin signaling by αEGFR-E-P125A is a promising strategy for the inhibition of VM, tumor growth, motility, and metastasis in TNBC and other EGFR-overexpressing tumors.
Project description:Lacking effective targeted therapies, triple-negative breast cancer (TNBCs) is highly aggressive, metastatic, and clinically challenging breast cancer subtype with worst prognosis. Despite survival dependency on the proteasome pathway genes, the FDA-approved proteasome inhibitors induced minimal clinical response in TNBC patients due to weaker proteasome inhibition. Here, we show that a novel proteasome inhibitor Marizomib (Mzb), inhibited multiple proteasome catalytic activities and induced better anti-tumor response in TNBC cell line and patient-derived xenografts alone and in combination with a standard-of-care chemotherapy, doxorubicin. Mechanistically, Mzb inhibits oxidative phosphorylation (OXPHOS) via PGC-1α suppression in conjunction with proteasome inhibition in TNBC cells. Development of metastatic disease, especially brain metastasis, remains a reason for a greater mortality rate amongst TNBC patients. Mzb reduces lung and brain metastasis in vivo by reducing circulating tumor cells and the expression of multiple epithelial-to-mesenchymal genes. We also demonstrate that Mzb-induced OXPHOS inhibition upregulates glycolysis to fulfill the metabolic demand of TNBC cells and hence, combined inhibition of glycolysis with Mzb leads to a synergistic anti-cancer activity in vivo. Collectively, our data provide a strong rationale for the clinical evaluation of Mzb in primary and metastatic TNBC patients.
Project description:The expression levels of JMJD6 and its correlation with H2A.XY39ph differed in TNBC and non-TNBC cells. In addition, we have previously shown that H2A.XY39ph levels are positively correlated with tumor size, histological grade and advanced TNM stage in breast cancer. To analyze the role of JMJD6 in regulating the characteristics of different subtypes of breast cancer, the transcriptomes of TNBC cells (SUM159) and non-TNBC cells (HCC1569) that overexpressed JMJD6 were compared. We speculate that JMJD6 overexpression cause autophagy pathway activation in TNBC via enhancing ATG genes expression.