title: Antisense suppression of the chloride intracellular channel family induces apoptosis, enhances tumor necrosis factor {alpha}-induced apoptosis, and inhibits tumor growth.
abstract: mtCLIC/CLIC4 is a p53 and tumor necrosis factor alpha (TNFalpha) regulated intracellular chloride channel protein that localizes to cytoplasm and organelles and induces apoptosis when overexpressed in several cell types of mouse and human origin. CLIC4 is elevated during TNFalpha-induced apoptosis in human osteosarcoma cell lines. In contrast, inhibition of NFkappaB results in an increase in TNFalpha-mediated apoptosis with a decrease in CLIC4 protein levels. Cell lines expressing an inducible CLIC4-antisense construct that also reduces the expression of several other chloride intracellular channel (CLIC) family proteins were established in the human osteosarcoma lines SaOS and U2OS cells and a malignant derivative of the mouse squamous papilloma line SP1. Reduction of CLIC family proteins by antisense expression caused apoptosis in these cells. Moreover, CLIC4-antisense induction increased TNFalpha-mediated apoptosis in both the SaOS and U2OS derivative cell lines without altering TNFalpha-induced NFkappaB activity. Reducing CLIC proteins in tumor grafts of SP1 cells expressing a tetracycline-regulated CLIC4-antisense substantially inhibited tumor growth and induced tumor apoptosis. Administration of TNFalpha i.p. modestly enhanced the antitumor effect of CLIC reduction in vivo. These results suggest that CLIC proteins could serve as drug targets for cancer therapy, and reduction of CLIC proteins could enhance the activity of other anticancer drugs.
authors.affiliation: Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Suh
authors.forename: Michihiro
authors.initials: M
authors.lastname: Mutoh
authors.forename: Michael
authors.initials: M
authors.lastname: Gerdes
authors.forename: John M
authors.initials: JM
authors.lastname: Crutchley
authors.forename: Tomoko
authors.initials: T
authors.lastname: Mutoh
authors.forename: Lindsay E
authors.initials: LE
authors.lastname: Edwards
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Dumont
authors.forename: Pooja
authors.initials: P
authors.lastname: Sodha
authors.forename: Christina
authors.initials: C
authors.lastname: Cheng
authors.forename: Adam
authors.initials: A
authors.lastname: Glick
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Yuspa
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D001859:Bone Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D002417:Cattle; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D018118:Chloride Channels / Q000037:antagonists & inhibitors* / Q000235:genetics; D016373:DNA, Antisense / Q000235:genetics*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012516:Osteosarcoma / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: C464459:CLIC4 protein, human; D018118:Chloride Channels; D016373:DNA, Antisense; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha