Areas specifically addressed include hormonal pathways, tumor protein p53 (TP53) and AT rich interactive domain 1A (SWI-like; ARID1A) mutation, and the breast cancer 1/2, early onset (BRCA1/2) mutation/poly (ADP-ribose) polymerase 1 (PARP1), phosphatidylinositol-4,5-bisphosphate 3- kinase, catalytic subunit alpha (PI3KCA)/v-akt murine thymoma viral oncogene homolog 1 (AKT1)/mechanistic target of rapamycin (MTOR), and mitogen-activated protein kinase kinase 1 and 2 (MAP2K1/2) pathways.
Expression levels of P38 MAPK and p-P38 MAPK as well as p-AKT, p-GSK3β, p-S6 kinase, p-MEK1 and p-ERK1/2 were quantitatively assessed using multiplex bead immunoassay in frozen specimens from 45 invasive ductal breast cancers.
These results indicate that Pin1 amplifies EGF signaling in breast cancer cells through its interaction with MEK1 and then enhances HER-2 expression, suggesting that Pin1 plays an important role in the overexpression of HER-2 through Pin1-MEK1-activator protein-2alpha signaling in breast cancer.
Pharmacological inhibitors of the GTP-binding proteins G(i)/G(o), phospholipase C, Src, and mitogenic-extracellular signal-regulated kinase 1/2 (MEK 1/2) decreased oleate-induced [3H]thymidine incorporation in the breast cancer cell line MDA-MB-231.
Using PD98059, an inhibitor of the ERK-kinase MEK1, we have here assessed the effects of ERK inhibition on the pattern of protein expression in the metastatic human breast cancer cell line MDA-MB-231.