CellSensor™ HSE-bla HeLa Cell Line

Activation of the heat shock response/unfolded protein response (HSR/UPR) occurs in response to a diversity of chemical, environmental, and physiological stress conditions. Transcriptional regulation of the human HSR is mediated by a family of three heat shock transcription factors (HSFs), HSF-1, -2, and -4. Stress-induced activation of quiescent HSF monomers results in their trimerization and accumulation in the nucleus, wherein they bind to and upregulate transcription of target genes (e.g. molecular chaperones, certain proteases, and other stress response genes) harboring a heat shock element (HSE). Downstream expression of heat shock protein family members (e.g. Hsp90 and Hsp70) that function as molecular chaperones to guide conformational states of client proteins is essential to maintaining the health of cells and protecting them from various acute and chronic stress conditions. As a result, HSR activation may provide therapeutic benefit to certain types of tissue trauma (e.g. brain and heart ischemia) and neurodegenerative disorders (e.g. Huntington disease, Alzheimer disease, and Parkinson disease). Conversely, since aberrant expression of chaperones has been associated with tumorigenesis, compounds that down-regulate the HSR and chaperone levels could provide useful tools for combating cancer.

To generate an effective readout for interrogating the HSR pathway, we engineered HeLa cervical cancer cells with an HSE driving beta-lactamase reporter gene expression (HSE-bla). A stably integrated pool of heat shock responsive cells was isolated by FACS and further evaluated using an inhibitor of Hsp90, 17-AAG. Hsp90 inhibition is known to upregulate HSF-1 activity leading to potent induction of the HSR, which can be readout using HSE-bla HeLa cells.