phorbol ester/breast neoplasms

Epithelial-mesenchymal transition (EMT) plays a pivotal role in the progression of cancer, and some transcription factors including Slug and Snail are known to be involved in EMT processes. It has been well established that the excess production of reactive oxygen species (ROS) and epigenetics such

The effects of the protein kinase C (PKC) activators, phorbol ester 12-O-tetradecanoyl-13-phorbol acetate (TPA) and the marine natural product, bryostatin 1, on the growth and morphology of human breast cancer cell lines were examined. TPA (1 to 100 nM) inhibited growth of four of six cell lines by

A previous study from this laboratory (Koga et al., Cancer Res., 48: 2734-2739, 1988) demonstrated that the growth inhibitory effect of 1,25-dihydroxyvitamin D3 in human breast cancer cells in vitro was associated with a decline in the concentration of epidermal growth factor receptor (EGF-R). In

In human breast cancer cell lines, an inverse relationship exists between the basal levels of oestrogen receptor (ER) and epidermal growth factor receptor (EGF-R) gene expression. In addition, the tumour-promoting phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) inhibits ER and stimulates

PMA and active phorbol esters stimulate the proliferation of various tumor cells, including ER-positive human breast tumor cell lines. However, the specific signaling pathways involved in the PMA-induced mitogenic effect on breast tumor cells have not been fully elucidated. In the present study, we

Increased protein kinase C (PKC) activity in malignant breast tissue and in most aggressive breast cancer cell lines has suggested a possible role of PKC in breast carcinogenesis and tumor progression. We have investigated here the involvement of PKC in the in vitro invasiveness and motility of

Protein kinase C (PKC) modulates growth, differentiation and apoptosis in a cell-specific fashion. Overexpression of PKC-alpha in MCF-7 breast cancer cells (MCF-7-PKC-alpha cell) leads to expression of a more transformed phenotype. The response of MCF-7 and MCF-7-PKC-alpha cells to phorbol esters

We have shown that in an estrogen receptor-negative multidrug-resistant subline of MCF-7 human breast carcinoma cells longer-term (24 h), but not shorter-term (30 min), treatments with clinically relevant (2-5 microM) concentrations of tamoxifen (TAM) inhibited phorbol ester-stimulated phospholipase

In both the normal and malignant human breast, cellular sensitivity to the proliferative and differentiative activities of the lactogenic hormones is conferred by expression of the prolactin receptor (PRLR). The PRLR is regulated by steroid hormones; however, recent findings have suggested that PRLR

Prostaglandin E2 (PGE2) levels are elevated in malignant human breast tissue. However, the cellular mechanisms regulating this arachidonate metabolism and the autocrine influence PGE2 production may have on breast cancer cell growth and function are unclear. In the present study, we have

Exposure of MCF-7 human breast cancer cells to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) leads to the inhibition of cell proliferation. We investigate here the short-term effects of TPA on subcellular distribution of protein kinase C, and on protein phosphorylation in cultured

Overexpression of protein kinase C-alpha in MCF-7 breast cancer cells (MCF-7-PKC-alpha cells) results in anchorage-independent growth and increased tumorigenicity of these cells in nude mice. MCF-7-PKC-alpha cells, unlike their parental MCF-7 cells, are sensitized to apoptosis by phorbol esters.

MCF-7 breast cancer cells grow as adherent cells, but following overexpression of protein kinase C-alpha these cells (MCF-7-PKC-alpha cells) become anchorage-independent and exhibit increased tumorigenicity in nude mice. MCF-7-PKC-alpha cells are also sensitized to apoptosis in response to phorbol

Previous studies have demonstrated an inverse relationship between estrogen receptor (ER) and epidermal growth factor receptor (EGF-R) gene expression in human breast cancer cells. This relationship was further investigated in MCF 7 cells treated with 12-O-tetradecanoylphorbol-13-acetate (TPA).

Basal-like breast cancers are commonly negative for expression of estrogen and progesterone receptors and HER-2 (triple-negative breast cancer), which makes this subtype of breast cancers more aggressive and less responsive to standard treatment. We have applied a small-scale chemical proteomics