Development of Na+-dependent hexose transport in a cultured line of porcine kidney cells

Abstract

LLC-PK1 cells in culture do not concentrate alpha-methylglucoside (alpha-meG) during their early growth phase but develop the capacity to concentrate this hexose as the growth rate decreases in confluent cultures. The concentrating ability is dependent on the Na+ electrochemical gradient and is inhibited by phlorizin with KI,0.5 approximately 0.2 microM. The development of the concentrative capacity can be accelerated by the Friend cell inducer hexamethylene bisacetamide (HMBA) and by the phosphodiesterase inhibitors dibutyryl cAMP, theophylline, and 1-methyl-3-isobutylxanthine (MIX). In cultures treated with any of these differentiation-accelerating chemicals, the development of alpha-meG concentrating capacity is severely inhibited by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) but not by inactive (in tumor promotion) analogs of TPA. In all cases, an early event in the development of alpha-meG accumulating capacity is an elevated intracellular cAMP concentration; however the results suggest that this increase in cAMP may be necessary but not sufficient to induce the differentiated hexose-accumulating capacity.

Overexpression of C-terminal Src Kinase Blocks 14,15-Epoxyeicosatrienoic Acid-induced Tyrosine Phosphorylation and Mitogenesis

“…Cell Culture-LLCPKcl4, an established renal proximal tubule epithelial cell line derived from pig kidney (29), was routinely cultured as described previously (4,30 cDNA Manipulation and Stable Transfection-In order to stably transfect CSK cDNA into LLCPKcl4 cells, the cDNAs containing the entire coding region of CSK were cut out from pcDNA-I vector (Invitrogen, San Diego, CA) by EcoRI digestion and then ligated into the EcoRI site of the neomycin resistant gene-containing vector pIRES1neo (CLONTECH Laboratories Inc., Palo Alto, CA). The sense orientation to the human cytomegalovirus (CMV) promoter was identified by restriction enzyme digestion analysis and further confirmed by sequencing analysis.…”

Role of EGF Receptor Activation in Angiotensin II–Induced Renal Epithelial Cell Hypertrophy

“…LLCPKcl4 was subcloned from the parental LLC-PK1 cells that were derived from pig kidney (15). This subclone retains many characteristics of renal proximal tubule epithelial cells but does not express Ang II receptors, unlike the parental LLC-PK1 cells (16).…”

The Plasma Membrane-associated Protein RS1 Decreases Transcription of the Transporter SGLT1 in Confluent LLC-PK1 Cells

“…Another factor observed in cell culture is cell confluence. During confluence of LLC-PK 1 cells, up-regulation of SGLT1 was observed, together with other differentiation-specific gene products of kidney proximal tubules such as tight junctions and brush-border enzymes (16,19,(22)(23)(24). The confluence-dependent regulation of SGLT1 in LLC-PK 1 cells appears to be mediated by protein kinases.…”

“…Regulation of SGLT1 has been studied in small intestine (7,(11)(12)(13), in Xenopus oocytes (14), and in the renal epithelial cell line LLC-PK 1 which is derived from porcine kidney proximal tubule cells (15)(16)(17)(18)(19)(20)(21)(22). One of the factors that affect the expression of SGLT1 in small intestine and LLC-PK 1 cells is extracellular D-glucose concentration (7,17,18).…”