Activation of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathway overcomes cisplatin resistance in ovarian carcinoma cells.

Objective: This study was aimed to elucidate the roles of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3'-kinase (PI3K)/Akt pathways in regulating cytotoxicity induced by cisplatin (CDDP) in ovarian carcinoma cells.

Methods: We treated 7 ovarian cancer cell lines with CDDP alone or with CDDP and either a PI3K inhibitor (LY294002), a MEK inhibitor (PD98059), or a MEK/ERK activator (phorbol 12-myristate 13-acetate [PMA]) and assessed cell viability, expression of MEK/ERK and PI3K/Akt, cell cycle distribution, and apoptosis. We also investigated the effect of combination treatment on survival in a xenograft model.

Chemotherapy consisting of paclitaxel and carboplatin benefits a patient with malignant mixed müllerian tumor of the fallopian tube.

Malignant mixed müllerian tumors (MMMT) of the fallopian tube are extremely rare, and optimal therapy for them is unknown. A 71-year-old woman presented to us with symptoms of abdominal distension and nausea. A right salpingo-oophorectomy was performed.

Simultaneous inhibition of the mitogen-activated protein kinase kinase and phosphatidylinositol 3'-kinase pathways enhances sensitivity to paclitaxel in ovarian carcinoma.

Paclitaxel (PTX), one of the key drugs used to treat ovarian cancer, activates the Raf-mitogen-activated protein kinase kinase (MEK) and phosphatidylinositol 3'-kinase (PI3K) pathways, both considered to be proliferation and cell-survival pathways. The present study aimed to clarify whether and how MEK and PI3K inhibitors affect sensitivity to PTX in ovarian cancer cells. We treated five ovarian cancer cell lines using PTX combined with MEK inhibitor (PD98059 [PD]) and PI3K inhibitor (LY294002 [LY]), then assessed cell viability, apoptosis, and expression of phosphorylated (p) MEK and pAkt.

PTEN is involved in the signal transduction pathway of contact inhibition in endometrial cells.

PTEN is involved in the regulation of normal cellular functions in addition to its well-known role as a tumor suppressor. In the present study, we have shown that stable transfection of the PTEN gene into PTEN-mutated endometrial carcinoma cells leads to contact inhibition accompanied by a decreased level of phosphorylated-Akt (p-Akt) expression, an increase in p27(Kip1), and a decrease in beta-catenin. PTEN-induced cells with contact inhibition exhibit G0-G1 cell-cycle arrest, and the Ki-67 labeling index is reduced.

PTEN-positive and phosphorylated-Akt-negative expression is a predictor of survival for patients with advanced endometrial carcinoma.

PTEN and the PI3K/Akt pathway are involved in the development and/or progression of endometrial carcinoma. To clarify the impact of the pathway-related molecules on prognosis, we analyzed PTEN, phosphorylated-Akt (p-Akt), and Ki-67 expression by immunohistochemistry in 99 patients with advanced endometrial carcinoma. PTEN-negative or PTEN-mixed staining was found in 66% of tumors.