Tet Transgene Activation is Disrupted in Lipogenic Triple Negative Breast Cancer Cells

Area of Science:

• Cell biology
• Molecular biology
• Metabolic engineering

Background:

• Mammalian cell engineering faces challenges with transgene expression variability due to native regulatory pathways.
• Factors like genomic integration site, cell type, and growth conditions affect transgene behavior.
• Transgene silencing is linked to transcription-replication collisions, heterochromatin, and viral defense mechanisms.

Purpose of the Study:

• To investigate the role of fatty acid metabolism in mediating transgene behavior.
• To understand how lipogenesis impacts reporter gene expression in epithelial breast cancer cells.

Main Methods:

• Utilized a Tet-TA regulated pCMV-AmCyan reporter transgene in epithelial breast cancer cells.
• Induced lipogenesis using adipocyte secretome.
• Performed transcription profiling to analyze gene expression changes.

Main Results:

• Lipogenesis induced by adipocyte secretome led to the loss of expression from the pCMV-AmCyan reporter transgene.
• Transcription profiling revealed activation of lipid droplet biosynthesis and repression of genomic loci.
• Preinduction of the pCMV promoter partially prevented transgene silencing during lipogenesis.

Conclusions:

• Fatty acid metabolism, specifically lipogenesis, acts as a mediator of transgene behavior.
• Shifting metabolic states, like increased lipogenesis, can affect the availability of substrates and cofactors for global chromatin remodeling, leading to transgene silencing.
• Preinducing the reporter transgene promoter can mitigate metabolic-induced silencing, offering a potential strategy for stable transgene expression.