The Three Receptor Tyrosine Kinases c-KIT, VEGFR2 and PDGFRα, Closely Spaced at 4q12, Show Increased Protein Expression in Triple-Negative Breast Cancer

Receptor degradation terminates signaling by activated receptor tyrosine kinases. Degradation of EGFR occurs in lysosomes and requires the switching of RAB5 for RAB7 on late endosomes to enable their fusion with the lysosome, but what controls this critical switching is poorly understood. We show that the tyrosine kinase FER alters PKCδ function by phosphorylating it on Y374, and that phospho-Y374-PKCδ prevents RAB5 release from nascent late endosomes, thereby inhibiting EGFR degradation and promoting the recycling of endosomal EGFR to the cell surface. The rapid association of phospho-Y374-PKCδ with EGFR-containing endosomes is diminished by PTPN14, which dephosphorylates phospho-Y374-PKCδ. In triple-negative breast cancer cells, the FER-dependent phosphorylation of PKCδ enhances EGFR signaling and promotes anchorage-independent cell growth. Importantly, increased Y374-PKCδ phosphorylation correlating with arrested late endosome maturation was identified in ∼25% of triple-negative breast cancer patients, suggesting that dysregulation of this pathway may contribute to their pathology.

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SHP2 acts both upstream and downstream of multiple receptor tyrosine kinases to promote basal-like and triple-negative breast cancer

Breast Cancer Research ◽

10.1186/s13058-015-0659-z ◽

2016 ◽

Vol 18 (1) ◽

Cited By ~ 17

Author(s):

Fatimah Matalkah ◽

Elisha Martin ◽

Hua Zhao ◽

Yehenew M. Agazie

Keyword(s):

Breast Cancer ◽

Triple Negative Breast Cancer ◽

Tyrosine Kinases ◽

Triple Negative ◽

Receptor Tyrosine Kinases ◽

Multiple Receptor

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Metabotropic glutamate receptor 1 is associated with unfavorable prognosis in ER-negative and triple-negative breast cancer

Scientific Reports ◽

10.1038/s41598-020-79248-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Anna E. M. Bastiaansen ◽

A. Mieke Timmermans ◽

Marcel Smid ◽

Carolien H. M. van Deurzen ◽

Esther S. P. Hulsenboom ◽

...

Keyword(s):

Breast Cancer ◽

Protein Expression ◽

Glutamate Receptor ◽

Triple Negative Breast Cancer ◽

Triple Negative ◽

Metabotropic Glutamate Receptor ◽

Metabotropic Glutamate ◽

Metabotropic Glutamate Receptor 1 ◽

Novel Target ◽

Cancer Tissues

AbstractNew therapies are an urgent medical need in all breast cancer subgroups. Metabotropic glutamate receptor 1 (mGluR1) is suggested as a potential new molecular target. We examined the prevalence mGluR1 expression in different clinically relevant breast cancer subgroups and determined its association with prognosis. In this retrospective cohort, 394 consecutive primary breast cancer tissues were incorporated into a tissue microarray and immunohistochemically stained for mGluR1. The prevalence of mGluR1 protein expression in different breast cancer subgroups was evaluated and correlated with metastasis-free survival (MFS) and overall survival (OS). In total, 56% (n = 219) breast cancer tissues had mGluR1 expression. In estrogen receptor (ER)-negative tumors, 31% (n = 18/58) had mGluR1 expression that was significantly associated with MFS (HR 5.00, 95% CI 1.03–24.35, p = 0.046) in multivariate analysis, independently from other prognostic factors. Of the 44 triple-negative breast cancer (TNBC), 25% (n = 11) expressed mGluR1. mGluR1 expression in TNBC was significantly associated with shorter MFS (HR 8.60, 95% CI 1.06–20.39, p = 0.044) and with poor OS (HR 16.07, 95% CI 1.16–223.10, p = 0.039). In conclusion, mGluR1 is frequently expressed in breast cancer. In ER-negative breast cancer and in TNBC mGluR1 protein expression is an unfavorable prognostic marker. This study provides rationale to explore mGluR1 as a novel target for breast cancer treatment, especially for the more aggressive TNBC.

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Enhanced Anticancer Activity of Nanoformulation of Dasatinib against Triple-Negative Breast Cancer by Reduced Metabolic Degradation

10.20944/preprints202104.0724.v1 ◽

2021 ◽

Author(s):

Fatemah Bahman ◽

Valeria Pittalà ◽

Mohamed Haider ◽

Khaled Greish

Keyword(s):

Breast Cancer ◽

Anticancer Activity ◽

Triple Negative Breast Cancer ◽

Tyrosine Kinases ◽

Triple Negative ◽

Growth Factor Receptor ◽

Initial Response ◽

Response To Chemotherapy

Triple negative breast cancer (TNBC) is the most aggressive breast cancer accounting for around 15% of identified breast cancer cases. TNBC, by lacking estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), is unresponsive to current targeted therapies. Existing treatment relies on chemotherapeutic treatment but, despite an initial response to chemotherapy, the inception of resistance and relapse is unfortunately common. Dasatinib is an approved second-generation inhibitor of multiple tyrosine kinases and literature data strongly support its use in the management of TNBC. However, dasatinib binds to plasma proteins and undergoes extensive metabolism through oxidation and conjugation. To protect dasatinib from fast pharmacokinetic degradation and to prolong its activity, it was encapsulated on poly(styrene-co-maleic acid) (SMA) micelles. The obtained SMA-dasatinib nanoparticles (NPs) were evaluated for their physicochemical properties, in vitro antiproliferative activity in different TNBC cell lines, and in vivo anticancer activity in a syngeneic model of breast cancer. Obtained results showed that SMA-dasatinib is more potent against 4T1 TNBC tumor growth in vivo compared to free drug. This enhanced effect was ascribed to the encapsulation of the drug protecting it from a rapid metabolism. Our finding highlights the often-overlooked value of nanoformulations in protecting its cargo from degradation. Overall, results may provide an alternative therapeutic strategy for TNBC management.

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