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Wood Smoke Stimulates Human Lung Cancer Cell Growth

PostPosted: Sun Jun 26, 2011 6:28 pm
by Wilberforce
Wood Smoke Stimulates Human Lung Cancer Cell Growth
Tafur et al ... acts.A3903


BACKGROUND: One – third of the world´s population burn organic material such as wood, dung or charcoal for cooking, heating and lightening. Chronic exposure to wood smoke has been implicated in the pathogenesis of pulmonary disorders including chronic obstructiv lung disease, interstitial lung disease, tuberculosis and lung cancer.

Thus, the accumulated clinical evidence suggests that exposure to wood smoke may be associated with an increased risk for lung cancer; there is still limited evidence in experimental studies about the carcinogenicity and/or progression of tumors from this exposure.

OBJECTIVE: To explore the effects of wood smoke on cell proliferation and cell apoptosis in human lung cancer cells.

METHODS: The human NSCLC cell line H460 and the carcinomic human alveolar basal epithelial cell line A549 were plated at a density of 4 x 103 cells per well in 12-well culture dishes. Cells were treated with different concentrations of wood smoke condensate [WSC] (0.01µg/mL, 0.1µg/mL and 1µg/mL).

To determine cell proliferation at indicated time points, cells were fixed with 100% iced-cold methanol and incubated with 0.2% crystal violet in 2.5% acetic acid. To extract the cell-bound dye, crystal violet stain was solubilized with 1% SDS.
The absorbance at 590 nm was determined on an AD 340C Beckman Coulter Absorbance Detector. To determine cell apoptosis, the Caspase-Glo 3/7 Assay, which measures caspase-3 and -7 activities, was used according to the manufacturer’s protocols.

All experiments were repeated a minimum of three times. All data collected from cell proliferation and caspase 3/7 activity assays were expressed as means ± SD. Statistical significance was determined with Student’s t test (p < 0.05).

RESULTS: A statistical significant increase in H460 cell and A549 cell numbers was observed after 24 hours of exposure to 0.01µg/mL of WSC comparing to controls (p = 0.014 and p = 0.0048). Higher concentrations and longer periods of WSC exposure decreased cell growth.

In order to examine if the effect of WSC is due to a reduction in cell apoptosis, the caspase 3/7 activity was performed. A statistical significant increase in H460 cell and A549 cell apoptosis was seen after 24 hours of exposure to to 0.01µg/mL of WSC comparing to controls (p = 0.038 and p = 0.0095).

CONCLUSION: Wood smoke condensate stimulates human lung cancer cell growth without reducing cell apoptosis. The mechanisms by which wood smoke condensate has an impact on cell proliferation need to be elucidated yet.

This abstract is funded by: None
Am J Respir Crit Care Med 183;2011:A3903
Internet address: Online Abstracts Issue