Phorbol ester stimulation of fibronectin-mediated cell adhesion

Area of Science:

• Cell biology
• Biochemistry

Background:

• Cell adhesion is crucial for biological processes.
• Fibronectin is a key extracellular matrix protein mediating cell adhesion.
• Protein kinase C (PKC) activation influences cellular responses.

Purpose of the Study:

• To investigate the effect of phorbol ester stimulation on Chinese hamster ovary (CHO) cell adhesion to fibronectin.
• To elucidate the role of protein kinase C (PKC) in modulating cell-fibronectin interactions.

Main Methods:

• Stimulation of CHO cells with 12-O-tetradecanoyl 13-acetate (TPA), a phorbol ester.
• Measurement of cell adhesion rates to fibronectin-coated substrata.
• Determination of EC50 values for phorbol ester-induced adhesion changes.
• Assessment of adhesion inhibition using the monoclonal antibody PB1.

Main Results:

• TPA stimulation significantly increased the rate of CHO cell adhesion to fibronectin.
• The EC50 for TPA-induced adhesion changes was approximately 8 nM, specific to PKC-activating phorbol esters.
• Stimulated cells required less fibronectin for adhesion and showed reduced sensitivity to PB1 antibody inhibition.
• PB1 antibody, which blocks fibronectin-mediated adhesion, showed 50% inhibition at a log-fold higher concentration in stimulated cells.

Conclusions:

• Phorbol ester stimulation, via PKC activation, enhances CHO cell adhesion to fibronectin.
• This enhancement is attributed to a modification of the fibronectin receptor.
• The modified receptor exhibits an apparent increase in its interaction with fibronectin.