Project description:The environment inside even a small tumor is characterized by total (anoxia) or partial oxygen deprivation, hypoxia. It has been shown that radiotherapy and some conventional chemotherapies may be less effective in hypoxia, and therefore it is important to investigate how different drugs act in different microenvironments. In the associated study we performed a large screening of the effects of 19 clinically used or experimental chemotherapeutic drugs on four different cell lines in conditions of normoxia, hypoxia and anoxia. A panel of 19 commercially available drugs: 5-fluorouracil, acriflavine, bortezomib, cisplatin, digitoxin, digoxin, docetaxel, doxorubicin, etoposide, gemcitabine, irinotecan, melphalan, mitomycin c, rapamycin, sorafenib, thalidomide, tirapazamine, topotecan and vincristine were tested for cytotoxic activity on the cancer cell lines A2780 (ovarian), ACHN (renal), MCF-7 (breast), H69 (SCLC) and U-937 (lymphoma). Parallel aliquots of the cells were grown at different oxygen pressures and after 72 hours of drug exposure viability was measured with the fluorometric microculture cytotoxicity assay (FMCA). Sorafenib, irinotecan and docetaxel were in general more effective in an oxygenated environment, while cisplatin, mitomycin c and tirapazamine were more effective in a low oxygen environment. Surprisingly, hypoxia in H69 and MCF-7 cells mostly rendered higher drug sensitivity. In contrast ACHN appeared more sensitive to hypoxia, giving slower proliferating cells, and consequently, was more resistant to most drugs. Gene expression analysis was performed on MCF-7 cells after 90 hours in either anoxic or hypoxic conditions, and compared to cells grown in a regular cell incubator. The gene expression analysis was performed to validate that the cells were hypoxic/anoxic and showed the characteristic hypoxia response. Microarray based mRNA profiling was used to charactarize cells grown in hypoxia and anoxia. In the associated study we performed a large screening of the effects of 19 clinically used or experimental chemotherapeutic drugs on four different cell lines in conditions of normoxia, hypoxia and anoxia. We fin that hypoxia/anoxia render cancer cells both more resistant and more sensistive, depending of the type of drug used. The gene expression analysis was performed to validate that the cells really were hypoxic/anoxic and showed the characteristic hypoxia response. The cell line used for the gene expression analysis was MCF-7.

Project description:BackgroundAnesthetic postconditioning is a cellular protective approach whereby exposure to a volatile anesthetic renders a tissue more resistant to subsequent ischemic/reperfusion event. Sevoflurane postconditioning (SPostC) has been shown to exert cardioprotection against ischemia/reperfusion injury, but the underlying mechanism is unclear. We hypothesized that SPostC protects cardiomyocytes against hypoxia/reoxygenation (H/R) injury by maintaining/restoring mitochondrial morphological integrity, a critical determinant of cell fate.MethodsPrimary cultures of neonatal rat cardiomyocytes (NCMs) were subjected to H/R injury (3 h of hypoxia followed by 3 h reoxygenation). Intervention with SPostC (2.4% sevoflurane) was administered for 15 min upon the onset of reoxygenation. Cell viability, Lactate dehydrogenase (LDH) level, cell death, mitochondrial morphology, mitochondrial membrane potential and mitochondrial permeability transition pore (mPTP) opening were assessed after intervention. Mitochondrial fusion and fission regulating proteins (Drp1, Fis1, Mfn1, Mfn2 and Opa1) were assessed by immunofluorescence staining and western blotting was performed to determine the level of protein expression.ResultsCardiomyocyte H/R injury resulted in significant increases in LDH release and cell death that were concomitant with reduced cell viability and reduced mitochondrial interconnectivity (mean area/perimeter ratio) and mitochondrial elongation, and with reduced mitochondrial membrane potential and increased mPTP opening. All the above changes were significantly attenuated by SPostC. Furthermore, H/R resulted in significant reductions in mitochondrial fusion proteins Mfn1, Mfn2 and Opa1 and significant enhancement of fission proteins Drp1 and Fis1. SPostC significantly enhanced Mfn2 and Opa1 and reduced Drp1, without significant impact on Mfn1 and Fis1.ConclusionsSevoflurane postconditioning attenuates cardiomyocytes hypoxia/reoxygenation injury (HRI) by restoring mitochondrial fusion/fission balance and morphology.

Project description:BackgroundMitochondrial dysfunction would ultimately lead to myocardial cell apoptosis and death during ischemia-reperfusion injuries. Autophagy could ameliorate mitochondrial dysfunction by autophagosome forming, which is a catabolic process to preserve the mitochondrial's structural and functional integrity. HO-1 induction and expression are important protective mechanisms. This study in order to investigate the role of HO-1 during mitochondrial damage and its mechanism.Methods and resultsThe H9c2 cardiomyocyte cell line were incubated by hypoxic and then reoxygenated for the indicated time (2, 6, 12, 18, and 24 h). Cell viability was tested with CCK-8 kit. The expression of endogenous HO-1(RT-PCR and Western blot) increased with the duration of reoxygenation and reached maximum levels after 2 hours of H/R; thereafter, the expression gradually decreased to a stable level. Mitochondrial dysfunction (Flow cytometry quantified the ROS generation and JC-1 staining) and autophagy (The Confocal microscopy measured the autophagy. RFP-GFP-LC3 double-labeled adenovirus was used for testing.) were induced after 6 hours of H/R. Then, genetic engineering technology was employed to construct an Lv-HO1-H9c2 cell line. When HO-1 was overexpressed, the LC3II levels were significantly increased after reoxygenation, p62 protein expression was significantly decreased, the level of autophagy was unchanged, the mitochondrial membrane potential was significantly increased, and the mitochondrial ROS level was significantly decreased. Furthermore, when the HO-1 inhibitor ZnPP was applied the level of autophagy after reoxygenation was significantly inhibited, and no significant improvement in mitochondrial dysfunction was observed.ConclusionsDuring myocardial hypoxia-reoxygenation injury, HO-1 overexpression induces autophagy to protect the stability of the mitochondrial membrane and reduce the amount of mitochondrial oxidation products, thereby exerting a protective effect.

Project description:The environment inside even a small tumor is characterized by total (anoxia) or partial oxygen deprivation, hypoxia. It has been shown that radiotherapy and some conventional chemotherapies may be less effective in hypoxia, and therefore it is important to investigate how different drugs act in different microenvironments. In the associated study we performed a large screening of the effects of 19 clinically used or experimental chemotherapeutic drugs on four different cell lines in conditions of normoxia, hypoxia and anoxia. A panel of 19 commercially available drugs: 5-fluorouracil, acriflavine, bortezomib, cisplatin, digitoxin, digoxin, docetaxel, doxorubicin, etoposide, gemcitabine, irinotecan, melphalan, mitomycin c, rapamycin, sorafenib, thalidomide, tirapazamine, topotecan and vincristine were tested for cytotoxic activity on the cancer cell lines A2780 (ovarian), ACHN (renal), MCF-7 (breast), H69 (SCLC) and U-937 (lymphoma). Parallel aliquots of the cells were grown at different oxygen pressures and after 72 hours of drug exposure viability was measured with the fluorometric microculture cytotoxicity assay (FMCA). Sorafenib, irinotecan and docetaxel were in general more effective in an oxygenated environment, while cisplatin, mitomycin c and tirapazamine were more effective in a low oxygen environment. Surprisingly, hypoxia in H69 and MCF-7 cells mostly rendered higher drug sensitivity. In contrast ACHN appeared more sensitive to hypoxia, giving slower proliferating cells, and consequently, was more resistant to most drugs. Gene expression analysis was performed on MCF-7 cells after 90 hours in either anoxic or hypoxic conditions, and compared to cells grown in a regular cell incubator. The gene expression analysis was performed to validate that the cells were hypoxic/anoxic and showed the characteristic hypoxia response. Microarray based mRNA profiling was used to charactarize cells grown in hypoxia and anoxia. In the associated study we performed a large screening of the effects of 19 clinically used or experimental chemotherapeutic drugs on four different cell lines in conditions of normoxia, hypoxia and anoxia. We fin that hypoxia/anoxia render cancer cells both more resistant and more sensistive, depending of the type of drug used. The gene expression analysis was performed to validate that the cells really were hypoxic/anoxic and showed the characteristic hypoxia response. The cell line used for the gene expression analysis was MCF-7.

Dataset Information

Anoxia-reoxygenation regulates mitochondrial dynamics through the hypoxia response pathway, SKN-1/Nrf, and stomatin-like protein STL-1/SLP-2.

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Anoxia-reoxygenation regulates mitochondrial dynamics through the hypoxia response pathway, SKN-1/Nrf, and stomatin-like protein STL-1/SLP-2.

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