title: Bioenergetic analysis of ovarian cancer cell lines: profiling of histological subtypes and identification of a mitochondria-defective cell line.
abstract: Epithelial ovarian cancer (EOC) is the most lethal of all gynecological cancers, and encompasses distinct histological subtypes that have specific genetic and tissues-of-origin differences. Ovarian clear cell carcinoma (OCCC) represents approximately 10% of cases and has been termed a stress responsive cancer. OCCC is characterized by increased expression of oxidative stress and glycolysis-related genes. In the present study, we hypothesized that bioenergetic profiling might uniquely distinguish OCCC from other EOC histological subtypes. Using an extracellular flux analyzer, OCCC lines (ES-2, TOV-21-G) were shown to be highly metabolically active, with high oxygen consumption rate (OCR) and high extracellular acidification rate (ECAR), indicative of enhanced mitochondrial oxidative phosphorylation and glycolytic rate, respectively. A high bioenergetics profile was associated with the cell lines' ability to form anchorage independent spheroids. Given their high glycolytic and mitochondrial activity, OCCC cells displayed strong sensitivity to 2-deoxy-D-glucose and Rotenone growth inhibition, although this chemosensitivity profile was not specific to only OCCC cells. Bioenergetic profiling also identified a non-OCCC cell line, OVCA420, to have severely compromised mitochondrial function, based on low OCR and a lack of stimulation of maximal respiration following application of the uncoupler FCCP. This was accompanied by mitochondrial morphology changes indicative of enhanced fission, increased expression of the mitochondrial fission protein Drp1, a loss of mitochondrial membrane potential and dependence on glycolysis. Importantly, this loss of mitochondrial function was accompanied by the inability of OVCA420 cells to cope with hypoxic stress, and a compromised ability to stabilize HIF-1α in response to 1% O2 hypoxia. This knowledge may be imperative for researchers planning to utilize this cell line for further studies of metabolism and hypoxia, and suggests that altered mitochondrial fission dynamics represents a phenotype of a subpopulation of EOCs.
authors.affiliation: Nanobioscience Constellation, College of Nanoscale Science and Engineering, State University of New York, Albany, New York, United States of America.
authors.forename: Usawadee
authors.initials: U
authors.lastname: Dier
authors.affiliation: Nanobioscience Constellation, College of Nanoscale Science and Engineering, State University of New York, Albany, New York, United States of America.
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Shin
authors.affiliation: Nanobioscience Constellation, College of Nanoscale Science and Engineering, State University of New York, Albany, New York, United States of America.
authors.forename: L P Madhubhani P
authors.initials: LP
authors.lastname: Hemachandra
authors.affiliation: Nanobioscience Constellation, College of Nanoscale Science and Engineering, State University of New York, Albany, New York, United States of America.
authors.forename: Larissa M
authors.initials: LM
authors.lastname: Uusitalo
authors.affiliation: Nanobioscience Constellation, College of Nanoscale Science and Engineering, State University of New York, Albany, New York, United States of America.
authors.forename: Nadine
authors.initials: N
authors.lastname: Hempel
mesh_terms: D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D015687:Cell Hypoxia / Q000187:drug effects; D045744:Cell Line, Tumor; D005260:Female; D006019:Glycolysis; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology; D063154:Mitochondrial Dynamics; D009363:Neoplasm Proteins / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology; D010101:Oxygen Consumption; D061209:Proton Ionophores / Q000494:pharmacology
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009363:Neoplasm Proteins; D061209:Proton Ionophores; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone