Features and Mechanisms

Early studies revealed that differentiated Caco-2 cells expressed several morphological and functional properties characteristic of small bowel enterocytes. Towards confluence they start to polarize acquiring a characteristic apical brush border with microvilli. Tight junctions form between adjacent cells, and they express enzyme activities typical of enterocytes, i.e. lactase, aminopeptidase N, sucrase-isomaltase and dipeptidylpeptidase IV. However, markers of colonocytes are also present in Caco-2 cells (Engle et al. 1998) (Table 10.1).

Table 10.1 Properties of Caco-2 cells


Grows in culture as an adherent monolayer of epithelial cells


Takes 14–21 days after confluence under standard culture conditions

Cell morphology

Polarized cells with tight junctions and brush border at the apical side

Electrical parameters

High electrical resistance

Digestive enzymes

Expresses typical digestive enzymes, membrane peptidases and disaccharidases of the small intestine (lactase, aminopeptidase N, sucrase-isomaltase and dipeptidylpeptidase IV)

Active transport

Amino acids, sugars, vitamins, hormones

Membrane ionic transport

Na+/K+ ATPase, H+/K+ ATPase, Na+/H+ exchange, Na+/K+/Cl− cotransport, apical Cl− channels

Membrane non-ionic transporters

Permeability glycoprotein (P-gp, multidrug resistance protein), multidrug resistance-associated protein, lung cancer-associated resistance protein


Vitamin B12, vitamin D3, EGFR (epidermal growth factor receptor), sugar transporters (GLUT1, GLUT2, GLUT3, GLUT5, SGLT1)

Cytokine production

IL-6, IL-8, TNFα, TGF-β1, thymic stromal lymphopoietin (TSLP), IL-15

Stability, Consistency and Reproducibility

During the 35 years that have passed since its establishment, Caco-2 cells have been propagated in a number of laboratories worldwide. Due to different culture conditions and different numbers of passages, Caco-2 cells have often acquired different properties. Thus, the expression of differentiation markers typical of enterocytes, change with increasing numbers of passages (Artursson et al. 2001). Also, parameters like transepithelial electric resistance (TEER) and proliferation rate have been reported to increase with passage number (Briske Andersson et al. 1997). It has also been documented that late passage cells may start growing in multilayers, a phenomenon that will affect TEER measurements, and make comparisons with results based on early passage cells difficult.

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