RCE1 corneal epithelial cell line: its variability on phenotype expression and differential response to growth factors.
BACKGROUND
By serial transfer of rabbit corneal epithelial cells, the spontaneous RCE1 cell line was previously established. These cells mimic the stage-dependent differentiation of the corresponding cell type.


METHODS
RCE1 cells were cultured either on plastic culture dishes or on collagen rafts to compare the epithelial ultrastructure after growth on these substrata. Phenotypic variability was studied after subcloning of cells. The differentiation ability of each subclone was determined by Western blot with antibodies against the differentiation-linked keratin pair K3/K12 and by measuring LDH activity and LDH isozymes in cytosolic extracts. The proliferative response of RCE1 cells to EGF, TGFalpha, amphiregulin, bFGF or IL-6 was determined under serum-free culture conditions.


RESULTS
Cells grown on collagen rafts formed 5- to 7-layered epithelia with characteristics closer to those found in normal corneal epithelium than cells cultivated on plastic substrata, which formed 3- to 5-layered epithelia. Subcloning experiments demonstrated that every proliferative cell is able to grow and constitute stratified epithelia expressing K3/K12 keratins. LDH levels in RCE1 epithelia were similar to those of cultured or freshly harvested corneal epithelia; however, they showed a slightly altered LDH isozyme set, with prevalence of LDH-3 isoform. Whereas EGF and TGF-alpha were equipotent, amphiregulin elicited a 4-fold lower proliferative response. Also, bFGF was 10-fold less mitogenic than EGF, and IL-6 had the lowest effect with an ED(50) 20-fold lower than EGF.


CONCLUSIONS
The results demonstrate that every RCE1 proliferative cell has the ability to generate epithelial sheets. We conclude that EGF and TGF-alpha are the major effectors of RCE1 cell proliferation.
Tamariz
Elisa
E
Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México, DF, México.
Hernandez-Quintero
Miriam
M
Sánchez-Guzman
Erika
E
Arguello
Carlos
C
Castro-Muñozledo
Federico
F
D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D003094:Collagen / Q000378:metabolism; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D004847:Epithelial Cells / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D005782:Gels / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000032:analysis; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D053551:Keratin-12 / Q000032:analysis; D053558:Keratin-3 / Q000032:analysis; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D051379:Mice; D010641:Phenotype; D011817:Rabbits; D016211:Transforming Growth Factor alpha / Q000494:pharmacology*
D005782:Gels; D036341:Intercellular Signaling Peptides and Proteins; D053551:Keratin-12; D053558:Keratin-3; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D003094:Collagen; D007770:L-Lactate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase