title: Radiosensitization of human melanoma cells by ribozyme-mediated inhibition of survivin expression.
abstract: Survivin is a structurally unique member of the inhibitors of apoptosis protein family and is involved in the control of cell division and inhibition of apoptosis. The notion that survivin is overexpressed in most human tumors but absent in normal adult tissues with only a few exceptions has led to the proposal of survivin as a promising therapeutic target for novel anticancer therapies. In this context, we generated a hammerhead ribozyme targeting the 3' end of the CUA110 triplet in the survivin mRNA. Two human melanoma cell lines (JR8 and M14) overexpressing survivin were stably transfected with the pRc/CMV vector carrying the ribozyme sequence. Two polyclonal cell populations proven to endogenously express ribozyme and characterized by a markedly lower survivin protein level (-60% and -50%, respectively) than JR8 and M14 parental cells were selected for the study. Ribozyme-expressing cells showed a significantly (p<0.01) increased sensitivity to gamma-irradiation (as detected by clonogenic cell survival) compared to JR8 and M14 cells. Moreover, in the JR8 cell line, the extent of radiation-induced apoptosis (in terms of percentage of apoptotic nuclei in cells stained with propidium iodide and level of caspase-3 catalytic activity) was markedly greater in ribozyme-expressing cells than in parental cells. These results demonstrate for the first time that attenuation of survivin expression renders human melanoma cells more susceptible to gamma-irradiation.
authors.affiliation: Department of Experimental Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan, Italy.
authors.forename: Marzia
authors.initials: M
authors.lastname: Pennati
authors.forename: Mara
authors.initials: M
authors.lastname: Binda
authors.forename: Gennaro
authors.initials: G
authors.lastname: Colella
authors.forename: Marco
authors.initials: M
authors.lastname: Folini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Citti
authors.forename: Raffaella
authors.initials: R
authors.lastname: Villa
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Daidone
authors.forename: Nadia
authors.initials: N
authors.lastname: Zaffaroni
mesh_terms: D017209:Apoptosis / Q000502:physiology / Q000528:radiation effects; D005720:Gamma Rays; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects*; D006801:Humans; D066298:In Vitro Techniques; D051034:Inhibitor of Apoptosis Proteins; D008545:Melanoma; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism; D009363:Neoplasm Proteins; D016337:RNA, Catalytic / Q000378:metabolism*; D012878:Skin Neoplasms; D000077022:Survivin; D014407:Tumor Cells, Cultured / Q000502:physiology / Q000528:radiation effects
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D016337:RNA, Catalytic; D000077022:Survivin