Lifestyle and Environment · Environmental Exposures
RRM Academy Synopsis
Sodium metavanadate gave lab-grown lung cells cancer-related traits
Sodium metavanadate gave cultured human lung cells cancer-related traits after four weeks of exposure. This lab study exposed a human lung airway cell line at a non-toxic level. Exposed cells formed more soft agar colonies. All but one of those clones closed a scratch wound faster than control cells. Gene activity changes in the clones lasted 11 weeks in culture.
Key Findings
- After four weeks of exposure, the number of colonies in soft agar rose with the dose, a test of anchorage-independent growth. Untreated cells formed significantly fewer colonies.
- All of the transformed clones except one closed a scratch wound within 30 hours. Parental cells and control clones did not.
- Gene expression analysis found 2010 differentially expressed genes in the transformed clones compared with the control clones.
- A total of 469 genes changed in the same direction in cells treated for five weeks, cells that recovered for one week, and the transformed clones.
- DSC3 showed the largest drop, a 20.8-fold decrease in all of the transformed clones. BRCA1 and DSC3 proteins were also lower in transformed clones than in control clones.
Interpretation
The experiment ran entirely in cultured cells from a human lung airway cell line called Beas-2B. These cells can divide indefinitely. The authors compared treated and untreated cells for colony growth, wound closure, and gene activity. The authors state that no clear evidence shows vanadium compounds cause cancer in humans. They note that long-term inhalation of vanadium pentoxide causes lung cancer in rodents. They conclude that chronic exposure produced changes consistent with cellular transformation, and they suggest an epigenetic mechanism of inheritance behind the persistent gene changes.
RRM Context
Restorative reproductive medicine takes a root-cause view of the whole person and the surrounding environment. The authors describe how people meet vanadium through food, burning fuel, some workplaces, and some dietary supplements. The study adds cell-level background on one vanadium compound to the research on metals in the environment.
Abstract
Pentavalent vanadium compounds induce intracellular changes in vitro that are consistent with those of other carcinogenic substances. While there is no clear evidence that vanadium compounds cause cancer in humans, vanadium pentoxide causes lung cancer in rodents after long-term inhalation exposures and in turn IARC has categorized it as a group 2B possible human carcinogen. The goal of this study was to investigate the carcinogenicity of NaVO3 in the human immortalized bronchial epithelial cell line, Beas-2B. Cells were treated with 10 μM NaVO3 for 5 weeks, with or without recovery time, followed by gene expression microarray analysis. In a separate experiment, cells were exposed to 1-10 μM NaVO3 for 4 weeks and then grown in soft agar to test for anchorage-independent growth. A dose-dependent increase in the number of colonies was observed. In scratch tests, NaVO3-transformed clones could repair a wound faster than controls. In a gene expression microarray analysis of soft agar clones there were 2010 differentially expressed genes (DEG) (adjusted p-value ≤ 0.05) in NaVO3-transformed clones relative to control clones. DEG from this experiment were compared with the DEG of 5 week NaVO3 exposure with or without recovery, all with adjusted p-values < 0.05, and 469 genes were altered in the same direction for transformed clones, 5 week NaVO3-treated cells, and the recovered cells. The data from this study imply that chronic exposure to NaVO3 causes changes that are consistent with cellular transformation including anchorage-independent growth, enhanced migration ability, and gene expression changes that were likely epigenetically inherited.
