Role of EIF5A2, a downstream target of Akt, in promoting melanoma cell invasion

Background: Cutaneous melanoma is a life-threatening skin cancer because of its poorly understood invasive nature and high metastatic potential. This study examines the importance of eukaryotic translation initiation factor 5A2 (EIF5A2) in melanoma pathogenesis. Methods: We examined EIF5A2 expression in 459 melanocytic lesions using tissue microarray. In addition, melanoma cell lines were subjected to invasion and cell proliferation assays, zymography, FACS and real-time PCR to investigate the role of EIF5A2 in cancer progression. Results: Positive EIF5A2 staining increased from dysplastic naevi to primary melanomas (PMs; P=0.001), and further increased in metastatic melanomas (P =0.044). Eukaryotic translation initiation factor 5A2 expression was correlated with melanoma thickness (P<0.001) and was inversely correlated with the 5-year survival of PM patients especially those with tumour <= 2mm thick. Strikingly, none of the latter died within 5 years in EIF5A2-negative staining group. Cox regression analysis revealed that EIF5A2 is an independent prognostic marker. Further, we found that EIF5A2 is a novel downstream target of phosphorylated Akt. Both melanoma cell invasion and MMP-2 activity increased and decreased with EIF5A2 overexpression and knockdown, respectively. Conclusion: We for the first time showed that EIF5A2, as a target of PI3K/Akt, promotes melanoma cell invasion and may serve as a promising prognostic marker and a potential therapeutic target for melanoma.