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 (TPA) was examined. TPA-treated MCF-7 cells demonstrated a modest cytostatic response associated wi...

Eukaryotic translation initiation factor 2 alpha (eIF2α), which is a component of the eukaryotic translation initiation complex, functions in cell death and survival under various stress conditions. In this study, we investigated the roles of eIF2α phosphorylation in cell death using the breast cancer cell lines MCF-7 and MCF-7/ADR. MCF-7/ADR cells are MCF-7-driven cells that have acquired resi...

This study was designed to investigate the role of protein kinase C (PKC) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling in tamoxifen (TAM)-induced apoptosis and drug resistance in human breast cancer cells. Drug-sensitive, or estrogen receptor (ER)-positive human breast carcinoma cells (MCF-7) and the multi-drug-resistant variant (ER-negative) MCF-7/ADR cells were treated wit...

Previous studies have demonstrated elevated levels of protein kinase C (PKC) activity in multidrug-resistant human breast carcinoma MCF-7/ADR cells compared to control drug-sensitive MCF-7/WT cells (R.L. Fine, J. Patel, and B.A. Chabner, Proc. Natl. Acad. Sci. USA, 85:582-586, 1988). In our present studies, immunohistochemical localization analysis using a polyclonal PKC antibody recognizing th...

The aim of the present study was to establish a tamoxifen-resistant cell line (MCF-7/TAM-R) and to investigate the therapeutic effect of G47Δ on this cell line both in vitro and in vivo. In the present study, the MCF-7/TAM-R monoclonal subline was established after exposing MCF-7 cells to tamoxifen for 21 days. Then, it was compared with a wild-type MCF-7 subline (MCF-7W), which was not treated...

It is known that the ovarian extract of Singkarak Lake Pufferfish (Tetraodon leiurus) has potential for chemoprevention in MCF-7 cells. However, expression Bcl-2 and Bax genes was associated with cancer. Therefore, this study aimed to analyze gene induced by MCF-7. The method an vitro experiment using control cells leiurus), Real-time PCR used examine genes. result showed had insignificant decr...

Breast cancer resistance protein (BCRP)/ABCG2 mediates concurrent resistance to chemotherapeutic agents, such as 7-ethyl-10-hydroxycamptothecin (SN-38), mitoxantrone, and topotecan, by pumping them out of cells. We previously reported that BCRP transports sulfated estrogens. In the present study, we show that at physiologic levels, estrogens markedly decrease endogenous BCRP expression in the e...

We have reported that nordihydroguaiaretic acid (NDGA) inhibits the tyrosine kinase activities of the IGF-1 receptor (IGF-1R) and the HER2 receptor in breast cancer cells. Herein, we studied the effects of NDGA on the growth of estrogen receptor (ER) positive MCF-7 cells engineered to overexpress HER2 (MCF-7/HER2-18). These cells are an in vitro model of HER2-driven, ER positive, tamoxifen resi...

sulfonamides are the first effective chemotherapeutic agents used for several years to cure or prevent systemic bacterial infections. in addition, this agents showed anti-carbonic anhydrase and cause cell cycle perturbation in the g1 phase, disruption of microtubule assembly, suppression of the transcription activator nf-y, angiogenesis and matrix metalloproteinase (mmp). in recent years, novel...

Abstract: Coxsackievirus B3 (CVB3) is the most common agent known to cause viral myocarditis. The viral genome encodes a single polyprotein that is cleaved to produce several proteins by virally encoded proteases. Most of this proteolytic processing is catalyzed by a cysteine protease called 3C. The 3C protease plays major role in viral replication and cellular damage. To understand the mecha...