Project description:Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer, associated with poor response to therapies and high mortality. We identify that phosphodiesterase 7A (PDE7A) is overexpressed in the majority of TNBC, and a higher level of PDE7A associates with poor prognosis. The PI3K/AKT pathway, via the transcription factor IRF1, stimulates the expression of PDE7A in TNBC cells. PDE7A inhibition attenuates TNBC growth in both cell culture and mouse models of TNBC. Inhibition of PDE7A suppresses de novo pyrimidine biosynthesis, in part through the downregulation of the enzyme dihydroorotate dehydrogenase (DHODH). DHODH suppression attenuates TNBC tumor growth, mirroring the effects of PDE7A inhibition, and ectopic DHODH expression rescues PDE7A-inhibition-induced tumor suppression. Pharmacological co-targeting of PDE7A and DHODH potently inhibits TNBC tumor growth and metastasis. These findings identify the PDE7A→ DHODH→ de novo pyrimidine biosynthesis pathway as a key driver of TNBC, offering additional therapeutic opportunities for TNBC patients.
Project description:Breast cancer is genetically and clinically heterogeneous. Triple negative cancer (TNBC) is a subtype of breast cancer usually associated with poor outcome and lack of benefit from target therapy. A pathway analysis in a microarray study was performed using TNBC compared with non-triple negative breast cancer (non-TNBC). Overexpression of several Wnt pathway genes, such as frizzled homolog 7 (FZD7), Low density lipoprotein receptor-related protein 6 (LRP6) and transcription factor 7 (TCF7) has been observed in TNBC. Focus was given to the Wnt pathway receptor, FZD7. To validate its function, inhibition of FZD7 using FZD7shRNA was carried out. Notably decreased cell proliferation, suppressed invasiveness and colony formation in triple negative MDA-MB-231 and BT-20 cells were observed. Mechanism study indicated that these effects occurred through silencing the canonical Wnt signaling pathway, as evidenced by loss of nuclear accumulation of ï?¢-catenin and decreased transcriptional activity of TCF7. In vivo study revealed that FZD7shRNA significantly suppressed the tumor formation in xenotransplation mice due to decrease cell proliferation. Our finding suggests that FZD7 involved canonical Wnt signaling pathway is essential for tumorigenesis of TNBC. Thus, FZD7 may be a biomarker and a potential therapeutic target for triple negative breast cancer. 14 pretreatment non-triple negative breast tumors compare with 5 triple negative breast tumor.
Project description:Triple negative breast cancer is an aggressive phenotypic breast cancer characterized by ER negative, PR negative and Her2 negative immunohistochemistry status. We embarked on a study to explore the transcriptome of Kenyan TNBC patients and identify potential biomarkers specific to Kenyan population. The transcriptome sequencing of tumors from Kenyan TNBC patients and comparisons with African American and Caucasian TNBC transcriptomes revealed several interesting targets and dysregulated pathways.
Project description:N-acylsphingosine amidohydrolase (ASAH1) expression is elevated in many cancer types including breast cancer. Therefore, we analyzed the role of ASAH1 in TNBC. Inhibition of ASAH1 expression in TNBC cell lines resulted in decreased tumor growth and metastasis
Project description:Triple-negative breast cancer (TNBC) is an aggressive and highly lethal disease with limited therapeutic options. While UFL1-mediated UFMylation has been implicated in various diseases, its role in TNBC remains unexplored. In this study, we demonstrate that AKT1 directly interacts with UFL1 and undergoes UFMylation at Lys189, Lys276, and Lys297. This modification enhances AKT phosphorylation and activation, promoting tumor growth and chemoresistance in TNBC. In turn, AKT phosphorylates UFL1 at Thr426, establishing a positive feedback loop that sustains high activity of both pro-oncogenic regulators in TNBC. Disrupting the UFL1-AKT interaction using the specific peptide PDAU-TAT significantly inhibits TNBC progression both in vitro and in vivo. Clinically, elevated pT426 UFL1 expression significantly correlates with increased pAKT levels in TNBC specimens. These findings uncover a crucial positive feedback loop between UFL1 and AKT that drives TNBC progression and suggest that targeting the UFL1-AKT axis could offer a promising therapeutic strategy for TNBC and potentially other aggressive cancers characterized by upregulated UFL1 and AKT activation.
Project description:Recent meta-analyses suggest triple-negative breast cancer (TNBC) is a heterogenous disease. In this study we sought to define these TNBC subtypes and identify subtype-specific markers and targets. We identified and confirmed four distinct, stable TNBC subtypes: (1) Luminal-AR (LAR); 2) Mesenchymal (MES); 3) Basal-Like Immune-Suppressed (BLIS), and 4) Basal-Like Immune-Activated (BLIA). RNA profiling analysis was conducted on 198 TNBC tumors (ER-negativity defined as Allred Scale value â¤2) with >50% cellularity (discovery set: n=84; validation set: n=114)
Project description:Development of targeted therapies will be a critical step towards reducing the mortality associated with triple-negative breast cancer (TNBC). To achieve this, we searched for targets that met three criteria: (1) pharmacologically targetable, (2) expressed in TNBC, and (3) expression is prognostic in TNBC patients. Since nuclear receptors have a well-defined ligand-binding domain and are thus highly amenable to small-molecule intervention, we focused on this class of protein. Our analysis identified TLX (NR2E1) as a candidate. RNA-Seq analysis revealed that TLX reduced the expression of genes implicated in the pro-proliferative KRAS signaling pathway as well as epithelial-mesenchymal transition (EMT), a cellular program known to drive metastatic progression. Indeed, TLX overexpression significantly decreased cell proliferation, migration and invasion, and robustly decreased the metastatic capacity of TNBC cells in murine models. Taken together, our work indicates that TLX retards the progression of TNBC. Several ligands have been shown to regulate the transcriptional activity of TLX, providing a framework for the future development of this receptor for therapeutic intervention.
Project description:Triple negative breast cancer is an aggressive phenotypic breast cancer characterized by ER negative, PR negative and Her2 negative immunohistochemistry status. We embarked on a study to explore the transcriptome of African American and Caucasian TNBC patients and identify race specific biomarkers.