Activation of c-Src/HER1/STAT5b and HER1/ERK1/2 signaling pathways and cell migration by hexachlorobenzene in MDA-MB-231 human breast cancer cell line.

Abstract

Hexachlorobenzene (HCB) is a widespread environmental pollutant. It is a dioxin-like compound and a weak ligand of the aryl hydrocarbon receptor (AhR) protein. HCB is a tumor cocarcinogen in rat mammary gland and an inducer of cell proliferation and c-Src kinase activity in MCF-7 breast cancer cells. This study was carried out to investigate HCB action on c-Src and the human epidermal growth factor receptor (HER1) activities and their downstream signaling pathways, Akt, extracellular-signal-regulated kinase (ERK1/2), and signal transducers and activators of transcription (STAT) 5b, as well as on cell migration in a human breast cancer cell line, MDA-MB-231. We also investigated whether the AhR is involved in HCB-induced effects. We have demonstrated that HCB (0.05μM) produces an early increase of Y416-c-Src, Y845-HER1, Y699-STAT5b, and ERK1/2 phosphorylation. Moreover, our results have shown that the pesticide (15 min) activates these pathways in a dose-dependent manner (0.005, 0.05, 0.5, and 5μM). In contrast, HCB does not alter T308-Akt activation. Pretreatment with a specific inhibitor for c-Src (4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d]pyrimidine [PP2]) prevents Y845-HER1 and Y699-STAT5b phosphorylation. AG1478, a specific HER1 inhibitor, abrogates HCB-induced STAT5b and ERK1/2 activation, whereas 4,7-orthophenanthroline and α-naphthoflavone, two AhR antagonists, prevent HCB-induced STAT5b and ERK1/2 phosphorylation. HCB enhances cell migration evaluated by scratch motility and transwell assays. Pretreatment with PP2, AG1478, and 4,7-orthophenanthroline suppresses HCB-induced cell migration. These results demonstrate that HCB stimulates c-Src/HER1/STAT5b and HER1/ERK1/2 signaling pathways in MDA-MB-231. c-Src, HER1, and AhR are involved in HCB-induced increase in cell migration. The present study makes a significant contribution to the molecular mechanism of action of HCB in mammary carcinogenesis.

• Authors: Carolina A Pontillo, María A García, Delfina Peña, Claudia Cocca, Florencia Chiappini, Laura Alvarez, Diana Kleiman de Pisarev, Andrea S Randi
• Journal: Toxicological sciences : an official journal of the Society of Toxicology (Toxicol Sci) Vol. 120 Issue 2 Pg. 284-96 (Apr 2011) ISSN: 1096-0929 [Electronic] United States
• PMID: 21205633 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Environmental Pollutants
• Receptors, Aryl Hydrocarbon
• STAT5 Transcription Factor
• STAT5B protein, human
• Hexachlorobenzene
• EGFR protein, human
• ErbB Receptors
• Protein-Tyrosine Kinases
• CSK Tyrosine-Protein Kinase
• src-Family Kinases
• CSK protein, human
• Extracellular Signal-Regulated MAP Kinases
• Mitogen-Activated Protein Kinase 1
• Mitogen-Activated Protein Kinase 3

Topics

• Breast Neoplasms (chemically induced, metabolism, pathology)
• CSK Tyrosine-Protein Kinase
• Cell Culture Techniques
• Cell Line, Tumor
• Cell Movement (drug effects)
• Dose-Response Relationship, Drug
• Environmental Pollutants (toxicity)
• ErbB Receptors (metabolism)
• Extracellular Signal-Regulated MAP Kinases (antagonists & inhibitors, metabolism)
• Female
• Hexachlorobenzene (toxicity)
• Humans
• Immunoprecipitation
• Mitogen-Activated Protein Kinase 1 (metabolism)
• Mitogen-Activated Protein Kinase 3 (metabolism)
• Protein-Tyrosine Kinases (antagonists & inhibitors, metabolism)
• Receptors, Aryl Hydrocarbon (metabolism)
• STAT5 Transcription Factor (metabolism)
• Signal Transduction
• src Homology Domains
• src-Family Kinases