Due to the absence of molecular markers for TNBC his treatment options remains limited, without proven targeted therapies, which emphasize the need for discovering molecular markers that could be targeted for patient treatment, An important number of TNBC cases harbor aberrations in the phosphoinositide 3-kinase (PI3K) pathway, leading to constitutive activation of the downstream signaling pathway.
AKT3 is an oncogene of known relevance in breast cancer, and as a proof of principle we show that inhibition of phosphoinositide 3-kinase (PI3K) activity, a protein upstream of AKT3, suppressed proliferation in TNBC preneoplastic cells.
Integrin β1, myosin light chain kinase and myosin IIA are required for activation of PI3K-AKT signaling following MEK inhibition in metastatic triple negative breast cancer.
TET1 expression correlated with sensitivity to drugs targeting the PI3K-mTOR pathway, and CRISPR-mediated deletion of TET1 in two independent TNBC cell lines resulted in reduced expression of PI3K pathway genes, upregulation of immune response genes, and substantially reduced cellular proliferation, suggesting dependence of oncogenic pathways on TET1 overexpression.
The addition of PI3K-mTOR inhibitors to cisplatin or paclitaxel increased the activity of chemotherapy in the TNBC and LGSOC models; whereas no added activity was observed in the LADC model.
Expression analysis of the panel of TNBC cell lines indicates that the expression levels of IGF2BP3 can be used as a potential predictor for sensitivity to the PI3K/IGF1R inhibitor combination.
The AKT inhibitor capivasertib has shown preclinical activity in TNBC models, and drug sensitivity has been associated with activation of PI3K or AKT and/or deletions of PTEN.
Using three-dimensional stromal-TNBC cells cultures, we demonstrate that CXCL12 - CXCR4 signaling significantly increases growth of TNBC cells and drug resistance through activation of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways.
Knockdown of WBP2 inhibited YAP transcription and the EGFR/PI3K/Akt signaling pathway in TNBC cells, and these effects were reversed by inhibition of miR-613.
Phosphatidylinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathways are frequently activated in TNBC patient tumors at the genome, gene expression and protein levels, and mTOR inhibitors have been shown to inhibit growth in TNBC cell lines.