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Treatment of Pheochromocytoma Cells with Recurrent Cycles of Hypoxia: A New Pseudohypoxic In Vitro Model.

ABSTRACT: Continuous activation of hypoxia pathways in pheochromocytomas and paragangliomas (PPGLs) is associated with higher disease aggressiveness, for which effective treatment strategies are still missing. Most of the commonly used in vitro models lack characteristics of these pseudohypoxic tumors, including elevated expression of hypoxia-inducible factor (HIF) 2α. To address this shortcoming, we investigated whether recurrent hypoxia cycles lead to continuous activation of hypoxia pathways under normoxic conditions and whether this pseudohypoxia is associated with increased cellular aggressiveness. Rat pheochromocytoma cells (PC12) were incubated under hypoxia for 24 h every 3-4 days, up to 20 hypoxia-reoxygenation cycles, resulting in PC12 Z20 cells. PC12 Z20 control cells were obtained by synchronous cultivation under normoxia. RNA sequencing revealed upregulation of HIF2α in PC12 Z20 cells and a pseudohypoxic gene signature that overlapped with the gene signature of pseudohypoxic PPGLs. PC12 Z20 cells showed a higher growth rate, and the migration and adhesion capacity were significantly increased compared with control cells. Changes in global methylation, together with the pseudohypoxic conditions, may be responsible for the increased aggressiveness of this new model. The established sub-cell line with characteristics of pseudohypoxic PPGLs represent a complementary model for further investigations, for example, with regard to new therapeutic approaches.

SUBMITTER: Helm J

PROVIDER: S-EPMC8834104 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature

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Treatment of Pheochromocytoma Cells with Recurrent Cycles of Hypoxia: A New Pseudohypoxic In Vitro Model.

Helm Jana J Drukewitz Stephan S Poser Isabel I Richter Susan S Friedemann Markus M William Doreen D Mohr Hermine H Nölting Svenja S Robledo Mercedes M Bornstein Stefan R SR Eisenhofer Graeme G Bechmann Nicole N

Cells 20220205 3

Continuous activation of hypoxia pathways in pheochromocytomas and paragangliomas (PPGLs) is associated with higher disease aggressiveness, for which effective treatment strategies are still missing. Most of the commonly used in vitro models lack characteristics of these pseudohypoxic tumors, including elevated expression of hypoxia-inducible factor (HIF) 2α. To address this shortcoming, we investigated whether recurrent hypoxia cycles lead to continuous activation of hypoxia pathways under norm ...[more]

PMID: 35159368

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Project description:ImportanceThe likelihood of achieving a live birth with repeat in vitro fertilization (IVF) is unclear, yet treatment is commonly limited to 3 or 4 embryo transfers.ObjectiveTo determine the live-birth rate per initiated ovarian stimulation IVF cycle and with repeated cycles.Design, setting, and participantsProspective study of 156,947 UK women who received 257,398 IVF ovarian stimulation cycles between 2003 and 2010 and were followed up until June 2012.ExposuresIn vitro fertilization, with a cycle defined as an episode of ovarian stimulation and all subsequent separate fresh and frozen embryo transfers.Main outcomes and measuresLive-birth rate per IVF cycle and the cumulative live-birth rates across all cycles in all women and by age and treatment type. Optimal, prognosis-adjusted, and conservative cumulative live-birth rates were estimated, reflecting 0%, 30%, and 100%, respectively, of women who discontinued due to poor prognosis and having a live-birth rate of 0 had they continued.ResultsAmong the 156,947 women, the median age at start of treatment was 35 years (interquartile range, 32-38; range, 18-55), and the median duration of infertility for all 257,398 cycles was 4 years (interquartile range, 2-6; range, <1-29). In all women, the live-birth rate for the first cycle was 29.5% (95% CI, 29.3%-29.7%). This remained above 20% up to and including the fourth cycle. The cumulative prognosis-adjusted live-birth rate across all cycles continued to increase up to the ninth cycle, with 65.3% (95% CI, 64.8%-65.8%) of women achieving a live birth by the sixth cycle. In women younger than 40 years using their own oocytes, the live-birth rate for the first cycle was 32.3% (95% CI, 32.0%-32.5%) and remained above 20% up to and including the fourth cycle. Six cycles achieved a cumulative prognosis-adjusted live-birth rate of 68.4% (95% CI, 67.8%-68.9%). For women aged 40 to 42 years, the live-birth rate for the first cycle was 12.3% (95% CI, 11.8%-12.8%), with 6 cycles achieving a cumulative prognosis-adjusted live-birth rate of 31.5% (95% CI, 29.7%-33.3%). For women older than 42 years, all rates within each cycle were less than 4%. No age differential was observed among women using donor oocytes. Rates were lower for women with untreated male partner-related infertility compared with those with any other cause, but treatment with either intracytoplasmic sperm injection or sperm donation removed this difference.Conclusions and relevanceAmong women in the United Kingdom undergoing IVF, the cumulative prognosis-adjusted live-birth rate after 6 cycles was 65.3%, with variations by age and treatment type. These findings support the efficacy of extending the number of IVF cycles beyond 3 or 4.

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Dataset Information

Treatment of Pheochromocytoma Cells with Recurrent Cycles of Hypoxia: A New Pseudohypoxic In Vitro Model.

Publications

Treatment of Pheochromocytoma Cells with Recurrent Cycles of Hypoxia: A New Pseudohypoxic In Vitro Model.

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