[Cytomegalovirus infection as a possible factor in the progression of neuroblastoma]

Abstract

Background: There is evidence that the infection with human cytomegalovirus is clinically associated with enhanced metastasis and progression of neuroblastoma disease. An in vitro model with HCMV-infected neuroblastoma cells (NB) was used to investigate whether HCMV modulates the metastatic potential of NB.

Methods: The neuroblastoma cell line UKF-NB-4 and its productively and persistently HCMV-infected variant UKF-NB-4AD169 were cocultured with human endothelial cells (EC). The rate of NB adherent to the endothelial monolayer and the rate of transmigrating NB was determined by means of combined reflexion interference contrast/phase contrast microscopy.

Results: UKF-NB-4AD169 adhered to and transmigrated through cocultured EC monolayer to a significantly higher extent compared with the non-infected cell line UKF-NB-4. At the cell-to-cell contact sites between UKF-NB-4AD169 and EC the intercellular endothelial contacts loosened resulting in the formation of reversible focal openings in the monolayer. This phenomenon was not observed with UKF-NB-4. The transendothelial migration rate of UKF-NB-4AD169 was therefore significantly higher than that of UKF-NB-4. The formation of focal openings in the endothelial monolayer and the enhanced transmigration rate of UKF-NB-4AD169 was suppressed in the presence of phenantroline, suggesting that HCMV-induced proteinases might be responsible for this phenomenon.

Conclusion: The results confirm our assumption that HCMV has the ability to modulate functional properties of NB which are essential for the interactions with endothelial cells and thus for metastasation. The clinical relevance of these findings has to be further defined yet by means of prospective studies with HCMV-infected neuroblastoma patients. Proteinase inhibitors could be valuable in the therapeutic treatment of these patients.