Expression of Epstein-Barr virus latent membrane proteins leads to changes in keratinocyte cell adhesion

Epstein-Barr virus (EBV) has 3 latent membrane proteins (LMPs) - LMP1, LMP2a, and LMP2b - which are expressed in nasopharyngeal carcinoma. Using keratinocyte cell lines expressing LMP2a and LMP2b and coexpressing LMP1/LMP2a, we grew organotypic raft cultures to analyze changes in morphology and expression of the cell adhesion molecule ICAM-1; α2, α3, α5, β1, and α6β4 integrins; laminin 5; E-cadherin; and desmoplakin. Cells expressing LMP2a or LMP2b were defective in their ability to mature and progress through normal squamous stratification when compared to the parental cell lines. Cells coexpressing LMP1/LMP2a additionally demonstrated 'pseudoinvasion' into the raft dermal equivalent. There was a consistent and dramatic up-regulation in the suprabasal expression of laminin 5 and α6β4 and β1 integrins in the LMP-expressing cell lines. ICAM-1, not expressed in the control cell lines, was up-regulated in the LMP-expressing cell lines. Expression of α3 and α5 integrins was also up-regulated in the LMP- expressing cell lines, while α2 demonstrated a loss of the normal basal layer expression. E-cadherin and desmoplakin expression patterns were essentially unchanged. We conclude that LMP2a and LMP2b singly, and LMP1/LMP2a coexpressed, are capable of altering keratinocyte cell adhesion molecule expression consistent with nasopharyngeal carcinoma.