Increased adenoviral transduction efficacy in human laryngeal carcinoma cells resistant to cisplatin is associated with increased expression of integrin αvβ3 and coxsackie adenovirus receptor

In our study, we investigated molecular mechanisms of increased adenoviral transduction efficacy in cisplatin-resistant human laryngeal carcinoma cells CA3(ST) as compared to parental cells HEp2. Using reverse transcription-PCR, the genes potentially implicated in adenoviral entry were screened. In cisplatin-resistant cells, only upregulation of alpha(v)beta(3) integrin was detected, which was additionally confirmed by flow cytometry. Moderately increased expression of CAR was determined in cisplatin-resistant CA3ST cells using flow cytometry and measurement of wild-type adenovirus Ad5CMVbetagal attachment. In order to test the implication of alpha(v)beta(3) integrin in transduction efficacy, 6 HEp2-derived alpha(v)beta(3)- expressing clones with graded expression of alpha(v)beta(3) were isolated. To a certain degree of density, expression of alpha(v)beta(3) positively correlated with AdSCMVbetagal transduction efficacy (i.e., increased viral transduction), suggesting a role of alpha(v)beta(3) in transduction efficacy. However, HEp2 clones with the highest 003 expression were negatively correlated with transduction efficacy (i.e., decreased viral transduction). This was shown to be associated with downregulation of alpha(v)beta(5) integrin, also involved in viral transduction, in clones with the highest alpha(v)beta(3) expression. The implication of CAR in increased adenoviral transduction efficacy in cisplatin resistant CA3(ST) Cells was further assessed by transduction experiments using adenoviral mutant AdSFbDelta639 whose entry is only to a very small extent dependent on the presence of CAR. Indeed, AdSFbDelta639 infected 2.5-fold more, in comparison to wildtype adenovirus, which infected 5-fold more efficiently resistant CA3(ST) cells than parental HEp2 cells, indicating that increased expression of CAR contributes to increased efficacy of adenoviral transduction. Thus, the data presented provide evidence that both alpha(v)beta(3) integrin and CAR are involved in increased adenoviral transduction efficacy in cisplatin resistant CA3(ST) cells. These findings may have significant implications in human gene therapy using adenoviruses, especially in patients after unsuccessful cisplatin treatment. (C) 2004 Wiley-Liss, Inc.