Differential effect of growth factors on invasion and proliferation of endocrine resistant breast cancer cells

• Published in: PloS one 2012-07, Vol.7 (7), p.e41847-e41847
• Main Authors: Khajah, Maitham A, Al Saleh, Sanaa, Mathew, Princy M, Luqmani, Yunus A
• Format: Article
• Language: English
• Subjects: AKT protein; Amino acids; Analysis; Benzamides - pharmacology; Biology; Biotechnology; Breast cancer; Breast Neoplasms; Cancer; Cell adhesion & migration; Cell Movement; Cell Proliferation; Chemokine CCL5 - physiology; Chemokines; Chromones - pharmacology; Collagenases - metabolism; Collagenases - secretion; Computer simulation; Diphenylamine - analogs & derivatives; Diphenylamine - pharmacology; Down-regulation; Epidermal growth factor; Epidermal Growth Factor - physiology; Erlotinib Hydrochloride; Experiments; Extracellular matrix; Extracellular signal-regulated kinase; Extracellular Signal-Regulated MAP Kinases - metabolism; Female; Gene expression; Gene Knockdown Techniques; Growth factors; Humans; Insulin-like growth factor I; Insulin-Like Growth Factor I - physiology; Invasiveness; Laboratories; Ligands; Lymphokines - physiology; Matrix metalloproteinase; MCF-7 Cells; Medical prognosis; Medicine; Metalloproteinase; Morpholines - pharmacology; Parenting; Penicillin; Pharmacy; Phosphorylation; Platelet-Derived Growth Factor - physiology; Protein Processing, Post-Translational; Protein-tyrosine kinase receptors; Proto-Oncogene Proteins c-akt - metabolism; Quinazolines - pharmacology; RANTES; Receptor, Epidermal Growth Factor - antagonists & inhibitors; Receptors, Estrogen - genetics; Receptors, Estrogen - metabolism; RNA, Small Interfering - genetics; Transfection; Transforming Growth Factor beta - physiology; Tumor cell lines; Tyrosine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0041847

We have established several breast cancer cell lines that exhibit a permanent ER-depleted phenotype, induced by shRNA transfection of MCF-7 cells, which afford a useful model for studying acquired endocrine resistance. Previously we showed that MDA-231 as well as ER-silenced cells could invade through simulated extracellular matrix components. However, the contribution of individual serum components responsible for cell invasion was not determined. In the present study, an under-agarose gel assay was used to quantitatively assess the invasive movement of two ER-silenced cell lines (pII and YS2.5) in comparison to the parental MCF-7, the ER negative MDA-231, and normal HBL100 cells, as well as a line that was ER-shRNA transfected but failed to exhibit ER down-regulation (YS1.2). We also examined the effect of the growth factors EGF, IGF-1, TGFβ, PDGFC and RANTES on pII cell invasion and proliferation. All breast cancer cell lines which had reduced ER expression exhibited a serum-dependent invasive ability related to the degree of induced ER loss. TGFβ treatment inhibited pII cell proliferation and enhanced their invasive ability but at a relatively high dose. IGF-1 and EGF enhanced pII cell proliferation, with the latter playing the major role in promoting cell invasion. PDGFC did not affect either process although it is highly expressed in pII cells. Differential effects were observed on activation of Akt and ERK1/2 suggesting their involvement as intracellular mediators of EGF induced invasion, in part through the regulation of matrix metalloproteinase activity. Targeting EGF receptor tyrosine kinase activity by erlotinib resulted in significant inhibition of both pII cell proliferation and directional invasion towards EGF suggesting that this drug has potential therapeutic usefulness for preventing spread of particularly endocrine resistant breast cancer.