September 13, 2012

Cells with LIP eat their neighbors

A transcription factor called LIP is capable of causing one cell to consume another.

(Wellcome Images)

Cell cannibalism – one cell “consuming” another cell – has been detected in highly malignant or metastatic tumors and correlates with poor prognosis. The processes that allow one cell to engulf another are poorly understood.

Maria Abreu, Ph.D., and Linda Sealy, Ph.D., associate professor of Cancer Biology, previously showed that expression of LIP (a truncated form of the transcription factor C/EBPbeta) in human breast cancer cell lines stimulates autophagy (degradation of the cell’s own components) and cell death. They now report that the autophagy appears to accompany, or possibly follow, the engulfment of neighboring cells by the LIP-expressing cells. They used DNA profiling, fluorescent imaging, cell sorting, and ultrastructural analysis to demonstrate that approximately 30 percent of the LIP-expressing cells engulf a neighboring cell.

The studies, reported July 31 in PLoS ONE, show that expression of LIP can mediate cell engulfment. Although the biological significance of cell cannibalism is unclear, it might promote tumor survival if LIP-expressing cancer cells engulf cells of the immune system to evade detection.

This research was supported by a National Institutes of Health Ruth L. Kirschstein National Research Service Award (GM089106).