Vacuolar protein sorting 4B, an ATPase protein positively regulates the progression of NSCLC via promoting cell division

Vacuolar protein sorting 4B (VPS4B), a member of ATPase family proteins, plays a crucial role in lysosomedependent degradation. Recently, it was found that VPS4B could negatively regulate breast cancer progression through promoting lysosomal-dependent degradation for EGFR. Nevertheless, other studies found that VPS4B was also essential for cell division and mitosis through insuring the maintenance of centrosome and spindle assembly. Thus, the role of VPS4B in cancer biology remains under debate. In this study, we analyzed the clinical significance of VPS4B in NSCLC. The expression of VPS4B was evaluated by Western blot in 8 paired fresh NSCLC tissues and immunohistochemistry on 105 paraffin-embedded slices. VPS4B was highly expressed in NSCLC and significantly associated with NSCLCs tumor size, histological differentiation, clinical stage and Ki-67. Besides, high VPS4B expression was an independent prognostic factor for NSCLC patients' poor survival. To determine whether VPS4B could regulate the proliferation of NSCLC cells, we knocked down the expression of VPS4B and analyzed the proliferation of A549 NSCLC cells using Western blot, CCK8 and flow cytometry assays, which together indicated that loss of VPS4B could inhibit cell cycle progress. These data suggest that VPS4B may promote the progression of NSCLC and be a biotarget for NSCLCs therapy. © 2013 Springer Science+Business Media New York.