The biobank.Materials and Methods Ethics statementThis study was approved by the scientific committee of our institutional Biobank, Tumorotheque du CRRC de Lille (approval ` nuCSTMT100). For this non-interventional study, devoid ofCell isolationThe isolation of proximal tubular cells (PT cells) was performed as described by Helbert et al. (1997) [8] and Van der Biest et al. (1994) [13] with some modifications. Renal cortical tissue wasFigure 2. Representative morphology of primary CD10/CD13 Title Loaded From File double-negative cells, CD10/CD13 cells double-positive, CD13+ and CD10+cells. (A) Primary cultures at passage 2 in serum-free medium. (B) Primary cultures at passage 2 in medium with 10 FBS. Magnification: 6100. doi:10.1371/journal.pone.0066750.gPrimary Human Proximal Renal Culture ModelFlow cytometryCD10 and CD13 labeling of PT cells was performed on 0.56106 cells using the same conditions as for the FACS protocol, with a Cyan ADP analyzer (Beckman Coulter).Western blottingCells were lysed using a 25 mM Tris-HCl pH 7.5, 150 mM NaCl, 1 Sodium deoxycholate, 0.1 Sodium Dodecyl Sulfate buffer containing protease inhibitors (Roche, Meylan, France) and were sonicated for 20 seconds. Total proteins were separated by electrophoresis on a 4?2 BisTris NuPAGE gel (Invitrogen) and were transferred onto nitrocellulose membrane using the iBlot 16985061 system (Invitrogen). Western blotting was performed by incubating nitrocellulose membranes with specific primary antibodies overnight at 4uC. The following antibodies were used against: aquaporin-1 (clone B11; Santa Cruz, Heidelberg, Germany; 1:100), N-cadherin (clone 3B9; Invitrogen; 1:500), MUC1 (clone CT2; LabVison Corporation, Francheville, France; 1:500), a-SMA (clone 4A8-2H3; Abnova, Le Perray en Yvelines, France; 1:200) and b-actin (clone 13E5; Cell Signaling Technology, Saint Quentin Yvelines, France; 1:1000). Membranes were incubated with secondary anti-rabbit, anti-Armenian hamster or anti-mouse antibodies coupled with horseradish peroxidase (Sigma Aldrich) for 45 minutes at room temperature. Immunoreactive bands were visualized by chemiluminescence using the Amersham ECL Plus Western Blotting Detection Reagent (GE Healthcare, Saclay, 23148522 France) on a Molecular Imager ChemiDoc XRS System (Bio-Rad, Marnes-laCoquette, France).Figure 3. Expression of differentiation markers in different cell populations. Representative western blots for (1) unsorted cells, (2) CD10/CD13 double-positive cells, (3) CD10+ cells, (4) CD13+ cells and (5) CD10/CD13 double-negative cells. Blots were incubated with antibodies against aquaporin-1, N-cadherin, MUC1. The b-actin protein was used as an internal control. Proteins were extracted from cells at passage 2. doi:10.1371/journal.pone.0066750.gcollected from fresh nephrectomy specimens for renal or urinary tract IF formamidase from Helicobacter pylori (PDB accession code 2E2L), and cancer (n = 16). Mirror image samples of cortical tissue collected were analyzed by a pathologist to ensure the absence of cancer and significant parenchymal lesions. Cortical samples were decapsulated and dissected in order to obtain 1 mm3 fragments. The fragments were then digested in 6 mL of complete DMEM (Dulbecco’s Modified Eagle’s Medium)/F12 1:1 medium (Invitrogen, Cergy Pontoise, France) containing 10 ng/mL Epidermal Growth Factor (EGF, Invitrogen), 1 penicillin/streptomycin (Invitrogen), 1 L-glutamine (Invitrogen), 15 mM HEPES (Sigma Aldrich, Saint Quentin Fallavier, France), 50 mM hydrocortisone (Sigma Aldrich), 5 mg/mL insulin (Invitrogen), 5 mg/mL transferrin (Sigm.The biobank.Materials and Methods Ethics statementThis study was approved by the scientific committee of our institutional Biobank, Tumorotheque du CRRC de Lille (approval ` nuCSTMT100). For this non-interventional study, devoid ofCell isolationThe isolation of proximal tubular cells (PT cells) was performed as described by Helbert et al. (1997) [8] and Van der Biest et al. (1994) [13] with some modifications. Renal cortical tissue wasFigure 2. Representative morphology of primary CD10/CD13 double-negative cells, CD10/CD13 cells double-positive, CD13+ and CD10+cells. (A) Primary cultures at passage 2 in serum-free medium. (B) Primary cultures at passage 2 in medium with 10 FBS. Magnification: 6100. doi:10.1371/journal.pone.0066750.gPrimary Human Proximal Renal Culture ModelFlow cytometryCD10 and CD13 labeling of PT cells was performed on 0.56106 cells using the same conditions as for the FACS protocol, with a Cyan ADP analyzer (Beckman Coulter).Western blottingCells were lysed using a 25 mM Tris-HCl pH 7.5, 150 mM NaCl, 1 Sodium deoxycholate, 0.1 Sodium Dodecyl Sulfate buffer containing protease inhibitors (Roche, Meylan, France) and were sonicated for 20 seconds. Total proteins were separated by electrophoresis on a 4?2 BisTris NuPAGE gel (Invitrogen) and were transferred onto nitrocellulose membrane using the iBlot 16985061 system (Invitrogen). Western blotting was performed by incubating nitrocellulose membranes with specific primary antibodies overnight at 4uC. The following antibodies were used against: aquaporin-1 (clone B11; Santa Cruz, Heidelberg, Germany; 1:100), N-cadherin (clone 3B9; Invitrogen; 1:500), MUC1 (clone CT2; LabVison Corporation, Francheville, France; 1:500), a-SMA (clone 4A8-2H3; Abnova, Le Perray en Yvelines, France; 1:200) and b-actin (clone 13E5; Cell Signaling Technology, Saint Quentin Yvelines, France; 1:1000). Membranes were incubated with secondary anti-rabbit, anti-Armenian hamster or anti-mouse antibodies coupled with horseradish peroxidase (Sigma Aldrich) for 45 minutes at room temperature. Immunoreactive bands were visualized by chemiluminescence using the Amersham ECL Plus Western Blotting Detection Reagent (GE Healthcare, Saclay, 23148522 France) on a Molecular Imager ChemiDoc XRS System (Bio-Rad, Marnes-laCoquette, France).Figure 3. Expression of differentiation markers in different cell populations. Representative western blots for (1) unsorted cells, (2) CD10/CD13 double-positive cells, (3) CD10+ cells, (4) CD13+ cells and (5) CD10/CD13 double-negative cells. Blots were incubated with antibodies against aquaporin-1, N-cadherin, MUC1. The b-actin protein was used as an internal control. Proteins were extracted from cells at passage 2. doi:10.1371/journal.pone.0066750.gcollected from fresh nephrectomy specimens for renal or urinary tract cancer (n = 16). Mirror image samples of cortical tissue collected were analyzed by a pathologist to ensure the absence of cancer and significant parenchymal lesions. Cortical samples were decapsulated and dissected in order to obtain 1 mm3 fragments. The fragments were then digested in 6 mL of complete DMEM (Dulbecco’s Modified Eagle’s Medium)/F12 1:1 medium (Invitrogen, Cergy Pontoise, France) containing 10 ng/mL Epidermal Growth Factor (EGF, Invitrogen), 1 penicillin/streptomycin (Invitrogen), 1 L-glutamine (Invitrogen), 15 mM HEPES (Sigma Aldrich, Saint Quentin Fallavier, France), 50 mM hydrocortisone (Sigma Aldrich), 5 mg/mL insulin (Invitrogen), 5 mg/mL transferrin (Sigm.