Human respiratory cells from nasal polyps as a model for gene transfer by non-viral cationic vectors

The influence of cell differentiation and proliferation on cationic vector mediated gene transfer into the explant-outgrowth cell culture from nasal p olyps was investigated. Respiratory cells were categorized into two groups based on the expression of cytokeratin filaments (CKs), which were used as differentiation markers. Outgrowths grown for 2 weeks expressed similar lev els of CKs 14, 13 and 18 showing a de-differentiated phenotype, while outgr owths cultured for 4 weeks presented very high levels of CK 13, high CK 14 and low CK 18 expression and were squamous differentiated. De-differentiate d cells presented higher proliferation indexes than squamous cells. Gene tr ansfer levels, as evaluated using a quantitative reporter gene (firefly luc iferase), were significantly higher in the 2- than in the 4-week-old outgro wths. Cationic vector transfected respiratory cells were located both proxi mally and distally to the explant, as shown by enzymatic staining of beta - galactosidase-positive cells. Respiratory cell outgrowths from nasal polyps can be considered a suitable model to study gene transfer protocols in vit ro.