Decreased proliferation of human melanoma cell lines caused by antisense RNA against translation factor elF-4AI

Control of translation initiation was recognised as a critical checkpoint for cell proliferation and tumor genesis. In human melanoma cells, we have previously reported consistent overexpression of translation initiation factor elF-4Al. Here, we investigated by transfection of antisense constructs its significance for the control of melanoma cell growth, The tetracycline-inducible expression system was established in melanoma cells, and three fragments of the 5'-, central-, and T-portion of the elF-4Al cDNA were subcloned in antisense and in sense orientation after a tetracycline inducible promoter. Significant proliferation decrease was obtained after transient transfection and induction of antisense RNA directed against the 5'- and the central portion (up to 10%), whereas, no effects were seen after induction of the T-fragment and the sense controls. Cell clones stably transfected with the central antisense fragment revealed after doxycycline induction reduced expression of endogeneous elF-4Al mRNA correlated with decreased proliferation rates (up to 6%). These data demonstrate the applicability of antisense strategies against translation factors in melanoma cells. Translation initiation factor elF-4Al contributes to the control of melanoma cell proliferation and may be taken into consideration when scheduling new therapeutic approaches targeting the translational control. (C) 2002 Cancer Research UK.