The phosphatidylinositol 3-kinase (PI3K) pathway is one of the critical signaling cascades playing important roles in the chemoresistance of human cancer cells, including ovarian cancer.
Dysregulation of the phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) and RAS/extracellular signal-regulated kinase (ERK) pathways is common in ovarian cancer, providing potential new targets for 2nd line therapy.
Activation of the phosphatidylinositol 3' kinase (PI3K) pathway occurs in a significant fraction of both types of ovarian cancer, driven predominantly by mutations in type I and amplification in type II.
Here, we show that dual inhibition of PI3K/mTOR in ovarian cancer-spheroids leads to death of inner matrix-deprived cells, whereas matrix-attached cells are resistant.
Taken together, these data suggest that PTEN over-expression may represent a novel therapeutic approach for chemoresistant human ovarian cancer and that this may involve a p53-mediated apoptotic cascade independent of the PI3K/Akt pathway.
These data demonstrate that different repertoires of downstream signaling proteins, particularly those of the MEK6-p38 MAPK-CK2 pathway and the PI3K pathway, are correlated with phenotypic manifestations of a cell culture model of OSE at progressive stages in the development of ovarian cancer.