A strategy to improve selectivity and targeting to epithelial-derived cancer cells.

Examination of genomic and proteomic changes associated with ras-driven epithelial to mesenchymal transformation (EMT) of polarized epithelial cells has led to an improved understanding of surface-expressed structures and alterations in components involved in intracellular trafficking events that are altered as normal cells become cancerous. We have previously identified a mechanism involved in the establishment of tight junction (TJ) cell-cell contacts orchestrated by the protein occludin (Ocln) and its ability to reverse EMT events. Previous studies have suggested an increased functional expression of a cell-surface import system for small peptides, hPepT1, in several types of cancer cells.

Transferrin receptor (CD71) is a marker of poor prognosis in breast cancer and can predict response to tamoxifen.

Transferrin receptor (CD71) is involved in the cellular uptake of iron and is expressed on cells with high proliferation. It may be implicated in promoting the growth of endocrine resistant phenotypes within ER+/luminal-like breast cancer. We used a panel of in vitro cell models of acquired resistance to tamoxifen (TAMR), Faslodex (FASR) or severe oestrogen deprivation (MCF-7X) and the ER+ luminal MCF-7 parental line to determine CD71 mRNA expression and to study transferrin (Tf) effects on in vitro tumour growth and its inhibition.

Acquired resistance to oestrogen deprivation: role for growth factor signalling kinases/oestrogen receptor cross-talk revealed in new MCF-7X model.

In vitro models of long-term oestrogen deprivation utilise increased oestrogen receptor (ER) and are oestrogen hypersensitive, with emerging evidence that growth factor signalling contributes and interacts with ER. However, such models are commonly derived in the presence of serum growth factors that may force the resistance mechanism. Our new in vitro model, MCF-7X, has thus been developed under conditions of both oestrogen and growth factor depletion.

Growth factor-driven mechanisms associated with resistance to estrogen deprivation in breast cancer: new opportunities for therapy.

There is an increasing body of evidence demonstrating that elevated growth signaling in breast cancer cells can promote forms of endocrine resistance in either an estrogen receptor-dependent or -independent manner. The current article reviews what is known about such growth factor signaling networks and resistance to estrogen withdrawal and considers the many novel therapeutic opportunities that stem from this knowledge.