Immortalized Epithelial Cells Derived From Human Colon Biopsies Express Stem Cell Markers and Differentiate In Vitro

Background & Aims

Long-term propagation of human colonic epithelial cells (HCEC) of adult origin has been a challenge; currently used HCEC lines are of malignant origin and/or contain multiple cytogenetic changes. We sought to immortalize human colon biopsy-derived cells expressing stem cell markers and retaining multilineage epithelial differentiation capability.

Methods

We isolated and cultured cells from biopsy samples of 2 patients undergoing routine screening colonoscopy. Cells were immortalized by expression of the nononcogenic proteins cyclin-dependent kinase 4 (Cdk4) and the catalytic component of human telomerase (hTERT) and maintained for more than 1 year in culture.

Results

The actively proliferating HCECs expressed the mesenchymal markers vimentin and α-smooth muscle actin. Upon growth arrest, cells assumed a cuboidal shape, decreased their mesenchymal features, and expressed markers of colonic epithelial cells such as cytokeratin 18, zonula occludens-1, mucins-1 and -2, antigen A33, and dipeptidyl peptidase 4. Immortalized cells expressed stem cell markers that included LGR5, BMI1, CD29, and CD44. When placed in Matrigel in the absence of a mesenchymal feeder layer, individual cells divided and formed self-organizing, cyst-like structures; a subset of cells exhibited mucin-2 or polarized villin staining.

Conclusions

We established immortalized HCECs that are capable of self-renewal and multilineage differentiation. These cells should serve as valuable reagents for studying colon stem cell biology, differentiation, and pathogenesis.

Keywords: Stem/Progenitor Cells, Epithelial Mesenchymal Transition, Self-Renewal, Multilineage Differentiation

Abbreviations used in this paper: BIO, bromoindirubin-3-oxime, 2D, two-dimensional, 3D, three-dimensional, Cdk4, cyclin-dependent kinase-4, EGF, epithelial growth factor, GSK-3β, glycogen synthase kinase-3β, HCEC CT, human colonic epithelial cell immortalized with Cdk4 and hTERT, hTERT, catalytic component of human telomerase, MUC, mucin, PD, population doublings, ZO-1, zonula occludens-1