TY - JOUR
T1 - Soluble human MDA-7/IL-24
T2 - Characterization of the molecular form(s) inhibiting tumor growth and stimulating monocytes
AU - Mumm, John B.
AU - Ekmekcioglu, Suhendan
AU - Poindexter, Nancy J.
AU - Chada, Sunil
AU - Grimm, Elizabeth A.
PY - 2006/12/1
Y1 - 2006/12/1
N2 - Interleukin-24 (IL-24), also known as melanoma differentiation-associated gene-7 (mda-7), is a member of the IL-10 family that exhibits both tumor suppressor and proinflammatory properties. We describe the purification of this novel dual-function tumor suppressor/cytokine from the supernatant of IL-24 gene-transfected HEK 293 cells and define the biochemical and functional properties of the soluble human IL-24 protein. Size exclusion chromatography demonstrates that an IL-24 macromolecular complex fractionates in a broad peak with a median of 110 kDa and comprises several IL-24 isoforms, identified by immunoblotting with anti-IL-24 polyclonal antibody after reducing SDS-PAGE analysis. IL-24 was found to associate with two serum components, albumin and C1q. Cation exchange purification results in the isolation of at least two N-linked glycosylated IL-24 dimers covalently associated via intermolecular disulfide bonds. These molecularly defined N-glycosylated IL-24 dimers elicited dose-dependent secretion of tumor necrosis factor-α (TNF-α) and IL-6 from human monocytes, as well as cytotoxicity to human melanoma cell lines. Thus, we demonstrated that the secreted, glycosylated, dimeric, human IL-24 is immunomodulatory to monocytes and exhibits tumor cell growth inhibition.
AB - Interleukin-24 (IL-24), also known as melanoma differentiation-associated gene-7 (mda-7), is a member of the IL-10 family that exhibits both tumor suppressor and proinflammatory properties. We describe the purification of this novel dual-function tumor suppressor/cytokine from the supernatant of IL-24 gene-transfected HEK 293 cells and define the biochemical and functional properties of the soluble human IL-24 protein. Size exclusion chromatography demonstrates that an IL-24 macromolecular complex fractionates in a broad peak with a median of 110 kDa and comprises several IL-24 isoforms, identified by immunoblotting with anti-IL-24 polyclonal antibody after reducing SDS-PAGE analysis. IL-24 was found to associate with two serum components, albumin and C1q. Cation exchange purification results in the isolation of at least two N-linked glycosylated IL-24 dimers covalently associated via intermolecular disulfide bonds. These molecularly defined N-glycosylated IL-24 dimers elicited dose-dependent secretion of tumor necrosis factor-α (TNF-α) and IL-6 from human monocytes, as well as cytotoxicity to human melanoma cell lines. Thus, we demonstrated that the secreted, glycosylated, dimeric, human IL-24 is immunomodulatory to monocytes and exhibits tumor cell growth inhibition.
UR - http://www.scopus.com/inward/record.url?scp=33845911722&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33845911722&partnerID=8YFLogxK
U2 - 10.1089/jir.2006.26.877
DO - 10.1089/jir.2006.26.877
M3 - Article
C2 - 17238830
AN - SCOPUS:33845911722
SN - 1079-9907
VL - 26
SP - 877
EP - 886
JO - Journal of Interferon and Cytokine Research
JF - Journal of Interferon and Cytokine Research
IS - 12
ER -