AMPK Activation of Apoptotic Markers in Human Breast Cancer Cell Lines with Different p53 Backgrounds: MCF-7, MDA-MB-231 and T47D Cells.

Background: Downregulation of AMPK has been established as a major contributor to carcinogenesis in many types of human cancer. We sought to investigate the influence of activated AMPK on apoptotic markers in human breast cancer cells differing in their p53 status, as well as estrogen receptor status (MCF-7 (p53+ and ER+), MDA-MB-231 (p53 mutant and ER-) and T47D (p53 mutant and ER+)).

Methods: We examined the effect of AICAR-activated AMPK on PARP cleavage, Bax redistribution, the involvement of intrinsic and extrinsic pathways of apoptosis using selective caspase inhibitors and cell cycle progression and p21 levels.

Differential crosstalk between the AMPK and PI3K/Akt pathways in breast cancer cells of differing genotypes: Leptin inhibits the effectiveness of AMPK activation.

AMP-activated protein kinase (AMPK), a sensor of cellular energy, is widely reported as a potential therapeutic target in treatment of breast and other cancers. The activated enzyme has been shown to be a promising anti-proliferative agent in breast cancer cell lines. However, little data exist on crosstalk between AMPK and the cellular survival axis of PI3K/Akt/mTOR pathway and the impact of microenvironment on cellular responses to AMPK activation.

Effects of activation of AMPK on human breast cancer cell lines with different genetic backgrounds.

Breast cancer remains a therapeutic challenge, and this has intensified the search for new drug targets. The AMP-activated protein kinase (AMPK) signalling pathway is emerging as having potential for intervention. We assessed the possible different effects of AMPK action on breast cancer cells by studying their impact on proliferation, apoptosis and the mitochondrial membrane potential in three breast cancer cell lines (MCF-7, MDA-MB-231 and T47D) differing in their p53 and estrogen receptor (ER) status.

Differential enhancement of the anti-cancer effect of doxorubicin by Akt inhibitors on human breast cancer cells with differing genetic backgrounds.

The phosphatidylinositol 3 OH-kinase (PI3K) pathway is a key intracellular signalling cascade in cellular survival. Our previous studies indicated that specific blockade of this enzyme led to sensitisation of human breast carcinoma cells to killing by doxorubicin through induction of both G2 arrest and apoptosis in some, but not all, breast cancer cells. In the present study, we report that inhibition of a down-stream component of this pathway, Akt, is an effective means of enhancing doxorubicin killing in some breast cell types.

Prognostic significance of Akt, phospho-Akt and BAD expression in primary breast cancer.

Apoptotic markers in breast cancer are reported to have prognostic significance. The aim of this study was to assess the prognostic value of Akt, phospho-Akt and BAD expression in primary tumours from breast cancer patients. Expression of phospho-Akt did not correlate with menopausal status, nodal involvement or tumour size, although there was a significant correlation between phospho-Akt and oestrogen receptor status and tumour grade.

Enhanced anti-cancer effect of a phosphatidylinositol-3 kinase inhibitor and doxorubicin on human breast epithelial cell lines with different p53 and oestrogen receptor status.

New efforts are being focused on signalling pathways as targets for cancer therapy. This particular study was designed to investigate whether blockade of the phosphatidylinositol 3OH-kinase (PI3K) pathway (a survival/anti-apoptosis pathway, overexpressed in various tumours) could sensitise human breast cancer cells to the effect of chemotherapeutics. Doxorubicin (Dox) and LY294002 (LY, a PI3K inhibitor) were used individually or in combination on MDA-MB-231 (p53 mutant, ER-), T47D (p53 mutant, ER+), and MCF-7 (p53 wildtype, ER+) human breast cancer cell lines, and on 184A1, a nonmalignant human breast epithelial cell line (p53 wildtype, ER-).

Protein kinase C-eta (PKC-eta) is required for the development of inducible nitric oxide synthase (iNOS) positive phenotype in human monocytic cells.

Several murine and human monocytic cell lines and monocyte-derived macrophages (MDM) from healthy volunteers were studied to compare their production of nitric oxide (NO) and induction of iNOS following endotoxin treatment. Although the human cells were sensitive to endotoxin and responded well by producing TNF-alpha and matrix metalloproteases (MMP), there was no induction of iNOS expression or NO production by any of these cells. Murine cells, however, produced large amounts of NO and expressed iNOS following similar endotoxin stimulation.

The survival effect of prolactin on PC3 prostate cancer cells.

Objectives: Recent studies suggest a paracrine/autocrine loop involving prolactin (PRL) within the human prostate. The aims of this study were to determine the effects of PRL on the growth and survival of prostate cancer cells and the intracellular signalling mechanisms underlying such effects.

Methods: The effect of PRL on proliferation of LNCaP, PC3 and DU145 was assessed by Coulter counting.