Chlorpyrifos produces dissimilar effects on proliferation in breast cancer cells

CLARA VENTURA; MARIEL NÚÑEZ; VIRGINIA GAIDO; V UBERTONE CORRALES; D MARTINEL LAMAS; ANDREA RANDI; ANDRÉS VENTURINO; ELENA RIVERA; CLAUDIA COCCA

Puerto Madryn, Chubut

Congreso; 46th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2010

SAIB

A large body of literatura suggest that environmental chemicals are involved in breast carcinogenesis. It has been postulated the use of the organophosphorous chlorpyrifos for replacing the current pesticide for fruit-bearing trees treatment in Alto Valle of Río Negro and Neuquén. The aim of the present study was to evaluate the effect of chlorpyrifos on cell proliferation of human breast cancer cell line, MCF-7.  Proliferation was evaluated by clonogenic assay and Bromodeoxyuridine (BrdU) incorporation; cell viability by MTT assay. Reactive Oxygen Species (ROS) were determined using DCF fluorescent staining and flow citometry.  Protein expression was assessed by Western Blot. Our results indicate that high concentration of chlorpyrifos (50 µM) decrease 40% clonogenic proliferation and 18% cell viability. The inhibitory effect on proliferation was associated to an increase of 32% in the content of ROS and 47% p27 protein expression. On the other hand, exposure of cells to low concentrations of chlorpyrifos (50 nM) stimulated BrdU incorporation in 88%. This effect was related to an enhanced expression of proliferating cell nuclear antigen (PCNA) and cyclin E. We concluded that chlorpyrifos modulates proliferation in a dose dependent way, increasing proliferation at low doses while decreasing it at high concentrations.