HK-2: An immortalized proximal tubule epithelial cell line from normal adult human kidney

Abstract

Studies assessing mechanisms of proximal tubular cell (PTC) physiology and pathophysiology increasingly utilize cell culture systems to avoid the complexity of whole organ/whole animal experiments. However, no well-differentiated PTC line derived from adult human kidney currently exists. Therefore, the goal of this research was to establish such a line by transduction with human papilloma virus (HPV 16) E6/E7 genes. A primary PTC culture from normal adult human renal cortex was exposed to a recombinant retrovirus containing the HPV 16 E6/E7 genes, resulting in a cell line designated HK-2 (human kidney-2) which has grown continuously in serum free media for more than one year. HK-2 cell growth is epidermal growth factor dependent and the cells retain a phenotype indicative of well-differentiated PTCs (positive for alkaline phosphatase, gamma glutamyltranspeptidase, leucine aminopeptidase, acid phosphatase, cytokeratin, alpha 3 beta 1 integrin, fibronectin; negative for factor VIII-related antigen, 6.19 antigen and CALLA endopeptidase). Furthermore, HK-2 cells retain functional characteristics of proximal tubular epithelium (Na+ dependent/phlorizin sensitive sugar transport; adenylate cyclase responsiveness to parathyroid, but not to antidiuretic, hormone). The E6/E7 genes are present in the HK-2 genome, as determined by PCR. To assess its potential usefulness as a tool for studying injury and repair, HK-2 cells were exposed to a toxic concentration of H2O2 +/- iron chelation (deferoxamine) or hydroxyl radical scavenger (Na benzoate) therapy. Only the former blocked H2O2 cytotoxicity, reproducing results previously obtained with freshly isolated rat proximal tubular segments. In conclusion, an immortalized adult human PTC line has been established by transduction with HPV 16 E6/E7 genes. It appears to be well-differentiated on the basis of its histochemical, immune cytochemical, and functional characteristics, and it can reproduce experimental results obtained with freshly isolated PTCs. Thus, this new PTC line could have substantial research application.

Rosiglitazone enhances glucose uptake in glomerular podocytes using the glucose transporter GLUT1

“…They were differentiated to adipocytes as previously described [23]. Finally, an immortalised human proximal tubular epithelial cell line (HK2) was used [24].…”

JunB and JunD Regulate Human Heme Oxygenase-1 Gene Expression in Renal Epithelial Cells

“…Cell Culture, Plasmids, and Transfection-HK-2 cells (ATCC, Manassas, VA), an immortalized human proximal tubular epithelial cell line from normal adult kidney (42), were grown on collagen-coated dishes in keratinocyte serum-free media supplemented with 5 ng/ml recombinant epidermal growth factor and 40 g/ml bovine pituitary extract. HEK293 cells (ATCC) were grown in minimum essential medium supplemented with 0.1 mM nonessential amino acids, 10% fetal bovine serum (FBS), 1 mM sodium pyruvate, and 1.5 mg/ml sodium bicarbonate.…”

Oxidative Stress Mediates a Reduced Expression of the Activating Receptor NKG2D in NK Cells from End-Stage Renal Disease Patients

“…HK-2 cells are anchorage-dependent, and cell growth is dependent on epidermal growth factor. HK-2 cells can reproduce experimental results obtained with freshly isolated proximal tubule cells (26). The cells were subcultured at 80% confluence in 75-cm 2 flasks using keratinocyte serum-free medium (Invitrogen) supplemented with 5 ng/ml recombinant epidermal growth factor and 0.04 mg/ml bovine pituitary extract.…”

“…Appropriate isotype controls were conducted on each sample. A PE-conjugated monoclonal anti-MICA Ab (BD Biosciences) was used to analyze MICA expression on monocytes and on a HK-2 cell line (26). The expression was defined by the relative mean fluorescence intensity (rMFI), where MICA rMFI ϭ MFI MICA/MFI isotype control.…”