title: Human surfactant protein D alters oxidative stress and HMGA1 expression to induce p53 apoptotic pathway in eosinophil leukemic cell line.
abstract: Surfactant protein D (SP-D), an innate immune molecule, has an indispensable role in host defense and regulation of inflammation. Immune related functions regulated by SP-D include agglutination of pathogens, phagocytosis, oxidative burst, antigen presentation, T lymphocyte proliferation, cytokine secretion, induction of apoptosis and clearance of apoptotic cells. The present study unravels a novel ability of SP-D to reduce the viability of leukemic cells (eosinophilic leukemic cell line, AML14.3D10; acute myeloid leukemia cell line, THP-1; acute lymphoid leukemia cell lines, Jurkat, Raji; and human breast epithelial cell line, MCF-7), and explains the underlying mechanisms. SP-D and a recombinant fragment of human SP-D (rhSP-D) induced G2/M phase cell cycle arrest, and dose and time-dependent apoptosis in the AML14.3D10 eosinophilic leukemia cell line. Levels of various apoptotic markers viz. activated p53, cleaved caspase-9 and PARP, along with G2/M checkpoints (p21 and Tyr15 phosphorylation of cdc2) showed significant increase in these cells. We further attempted to elucidate the underlying mechanisms of rhSP-D induced apoptosis using proteomic analysis. This approach identified large scale molecular changes initiated by SP-D in a human cell for the first time. Among others, the proteomics analysis highlighted a decreased expression of survival related proteins such as HMGA1, overexpression of proteins to protect the cells from oxidative burst, while a drastic decrease in mitochondrial antioxidant defense system. rhSP-D mediated enhanced oxidative burst in AML14.3D10 cells was confirmed, while antioxidant, N-acetyl-L-cysteine, abrogated the rhSP-D induced apoptosis. The rhSP-D mediated reduced viability was specific to the cancer cell lines and viability of human PBMCs from healthy controls was not affected. The study suggests involvement of SP-D in host's immunosurveillance and therapeutic potential of rhSP-D in the eosinophilic leukemia and cancers of other origins.
authors.affiliation: Molecular Biochemistry and Diagnostics, Institute of Genomics and Integrative Biology (IGIB), New Delhi, Delhi, India ; Centre for Molecular Medicine, National Institute of Immunology (NII), New Delhi, India.
authors.forename: Lakshna
authors.initials: L
authors.lastname: Mahajan
authors.affiliation: Innate Immunity, National Institute for Research in Reproductive Health (NIRRH), Mumbai, Maharashtra, India.
authors.forename: Hrishikesh
authors.initials: H
authors.lastname: Pandit
authors.affiliation: Molecular Biochemistry and Diagnostics, Institute of Genomics and Integrative Biology (IGIB), New Delhi, Delhi, India ; Innate Immunity, National Institute for Research in Reproductive Health (NIRRH), Mumbai, Maharashtra, India.
authors.forename: Taruna
authors.initials: T
authors.lastname: Madan
authors.affiliation: Molecular Biochemistry and Diagnostics, Institute of Genomics and Integrative Biology (IGIB), New Delhi, Delhi, India ; Proteomics Research Facility, Centre for Cellular and Molecular Biology (CCMB), Hyderabad, Andhra Pradesh, India.
authors.forename: Poonam
authors.initials: P
authors.lastname: Gautam
authors.affiliation: Innate Immunity, National Institute for Research in Reproductive Health (NIRRH), Mumbai, Maharashtra, India.
authors.forename: Ajit K
authors.initials: AK
authors.lastname: Yadav
authors.affiliation: Department of Obstetrics and Gynecology, K E M Hospital and Seth G. S. Medical College, Mumbai, Maharashtra, India.
authors.forename: Himangi
authors.initials: H
authors.lastname: Warke
authors.affiliation: Proteomics Research Facility, Centre for Cellular and Molecular Biology (CCMB), Hyderabad, Andhra Pradesh, India.
authors.forename: Curam S
authors.initials: CS
authors.lastname: Sundaram
authors.affiliation: Proteomics Research Facility, Centre for Cellular and Molecular Biology (CCMB), Hyderabad, Andhra Pradesh, India.
authors.forename: Ravi
authors.initials: R
authors.lastname: Sirdeshmukh
authors.affiliation: Molecular Biochemistry and Diagnostics, Institute of Genomics and Integrative Biology (IGIB), New Delhi, Delhi, India.
authors.forename: P Usha
authors.initials: PU
authors.lastname: Sarma
authors.affiliation: Centre for Infection, Immunity and Disease Mechanisms (CIIDM), Brunel University, London, United Kingdom.
authors.forename: Uday
authors.initials: U
authors.lastname: Kishore
authors.affiliation: Centre for Molecular Medicine, National Institute of Immunology (NII), New Delhi, India.
authors.forename: Avadhesha
authors.initials: A
authors.lastname: Surolia
mesh_terms: D000704:Analysis of Variance; D017304:Annexin A5; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D004804:Eosinophils; D016650:Fluorescein-5-isothiocyanate; D005786:Gene Expression Regulation / Q000187:drug effects*; D025741:HMGA1a Protein / Q000378:metabolism*; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects*; D040901:Proteomics; D037663:Pulmonary Surfactant-Associated Protein D / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D017304:Annexin A5; D037663:Pulmonary Surfactant-Associated Protein D; D016159:Tumor Suppressor Protein p53; D025741:HMGA1a Protein; D016650:Fluorescein-5-isothiocyanate