title: Proteomic analysis of mitochondria-to-nucleus retrograde response in human cancer.
abstract: All tumors examined to date contain mutations in mitochondrial DNA (mtDNA). In addition, depletion of mtDNA is reported in a variety of tumors. Mitochondrial dysfunction resulting from changes in mtDNA invokes mitochondria-to-nucleus retrograde response in human cells. To identify proteins involved in retrograde response and their potential role in tumorigenesis, we carried out a comparative proteomic analysis using a cell line in which the mitochondrial genome was completely depleted (rho(0) cells lacking all mtDNA-encoded protein subunits), a cybrid cell line in which mtDNA was restored, and the parental cell line. Our comparative proteomic approach revealed marked changes in the cellular proteome and led us to identify quantitative changes in expression of several proteins. We found that subunits of complex I and complex III, molecular chaperones, and a protein involved in cell cycle control were downregulated and Inosine 5'-monophosphate dehydrogenase type 2 (IMPDH2) involved in nucleotide biosynthesis was upregulated in rho(0) cells. Our findings demonstrate that the expression of proteins is restored to wild type level by transfer of wild type mitochondria to rho(0) cells, suggesting that these proteins play key roles in retrograde response. To determine a potential role for identified retrograde responsive proteins in tumorigenesis, we analyzed the expression of UQCRC1 gene (encoding ubiquinol cytochrome-c reductase core protein I) in breast and ovarian tumors. We found that (1) UQCRC1 was highly expressed in breast (74%) and ovarian tumors (34%) and (2) the expression positively correlated with cytochrome c-oxidase (COXII) encoded by mtDNA. Our study opens an avenue for identification of retrograde proteins as potential tumor suppressors or oncogenes involved in carcinogenesis.
authors.affiliation: Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, USA.
authors.forename: Mariola
authors.initials: M
authors.lastname: Kulawiec
authors.forename: Hilal
authors.initials: H
authors.lastname: Arnouk
authors.forename: Mohamed Mokhtar
authors.initials: MM
authors.lastname: Desouki
authors.forename: Latif
authors.initials: L
authors.lastname: Kazim
authors.forename: Ivan
authors.initials: I
authors.lastname: Still
authors.forename: Keshav K
authors.initials: KK
authors.lastname: Singh
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism; D004338:Drug Combinations; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D016889:Endometrial Neoplasms / Q000378:metabolism / Q000473:pathology; D004717:Endometrium / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D006822:Hybrid Cells; D007124:Immunoenzyme Techniques; D007797:Laminin / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009361:Neoplasm Invasiveness / Q000473:pathology; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology; D011509:Proteoglycans / Q000378:metabolism; D020543:Proteome / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D046888:Tissue Array Analysis; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004338:Drug Combinations; D007797:Laminin; D024101:Mitochondrial Proteins; D011509:Proteoglycans; D020543:Proteome; C059485:matrigel; D003094:Collagen; D003576:Electron Transport Complex IV; D020741:rho GTP-Binding Proteins; D014450:Electron Transport Complex III