FOXC1 in ER- Tumors

FOXC1 IN ER- TUMORS

FOXC1 is significantly overexpressed in triple-negative breast cancer (TNBC) and acts as a key regulator of its aggressive behavior. High levels of FOXC1 are associated with poor prognosis, resistance to chemotherapy, and increased metastasis in TNBC patients.

Super Enhancer Driven FOXC1 Activation, Auto-Regulation and Core Regulatory Circuit (CRC)

In TNBC, FOXC1 may bind to Super Enhancers in its own regulatory region, thus providing a positive feedback loop where FOXC1 reinforces its own expression and interacts with other transcription factors to form a core regulatory circuit sustaining high expression levels required to maintain an aggressive, invasive, metastatic phenotype.

FOXC1 non-canonically activates genes (i.e., Wnt, Notch, Hedgehog) which further activates EMT core transcription factors.
EMT core factors (i.e., Snail, Slug, Zeb1) suppress ER activation and ER signaling abrogating ER suppressive effects on EMT.
Competitive binding of FOXC1 at the ER promoter blocks GATA3 ER activation, silencing ER activation.

FOXC1 modulates Core Regulatory Circuits (CRC) driving proliferation, EMT, invasion, metastasis, and chemo-resistance

FOXC1 regulates cell fate driving major gene networks involved in invasion and metastasis.

FOXC1 and its downstream network require sustained activation to maintain cellular identity. A core regulatory circuit (CRC) in cancer is a network of transcription factors (TFs) and super-enhancers (SEs) that maintain a cancer cell's specific gene expression and identity. These TFs are self-regulating and cross-regulate each other through feed-forward loops, binding to SEs to control the expression of lineage-specific genes. FOXC1 drives invasion and metastasis in the FOXC1 CRC:

Sustained high level expression of FOXC1 is central to the oncogenic role driving aggressive features of growth, metastasis and chemoresistance.
Key cofactors and interacting partners (NR2F2, epigenetic regulators)
Major downstream signal pathways (Wnt, NF-κB, MMP, FGFR1)
Migration and metastasis (CXCR4)
Angiogenesis (VEGF)
Proliferation (cMYC, Cyclin D1)
Dormancy (Hair Follicle Stem Cell, Bone Marrow Stem Cells)

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