I am trying to establish a model of hypoxia-reoxygenation in HK-2 cells in order to determine their expression of kidney injury biomarkers (e.g. KIM-1, NGAL, etc.) via qPCR. However, I am finding that the expression of these biomarkers does not increase when I subject cells to hypoxia damage. My starting conditions have been hypoxia for 24/48 hours at 1% O2, and reoxygenation for 24/48h. My question is: are HK-2 cells reliable in their expression of kidney injury biomarkers? Do they resemble non-inmmortalized kidney cells?