Effects of hyperbaric oxygen treatment on gastric cancer cell line SGC7901

Hyperbaric oxygen enhances X-ray induced ferroptosis in oral squamous cell carcinoma cells

OBJECTIVE

The objective of this study was to investigate the combined effect of X-ray radiation (IR) and hyperbaric oxygen (HBO) on oral squamous cell carcinoma (OSCC) cells and to explore the possible molecular mechanism.

METHODS

The OSCC cells were treated with or without IR, together with or without HBO co-exposure. Cells were transfected with specific plasmids using Lipofectamine 2000. The cell varieties, apoptosis markers, and ferroptosis markers were determined by using appropriate method. OSCC xenograft mice model was categorized into several subgroups according to the specific treatement. GPX4 expressions were determined by immunohistochemistry (IHC) in OSCC tissues and were tested by ELISA in serums from OSCC patients.

RESULTS

The co-exposure of IR and HBO significantly strengthened the cytotoxicity of IR on SCC15-S cells in ferroptosis-dependent manner. The regulated GPX4/ferroptosis mediated the HBO function on re-sensitizing the radio-resistant OSCC cells to IR. In xenograft mice, co-exposure of IR and HBO can significantly reduce the tumor under IR activation compared with IR alone. Clinical data indicated that high GPX4 levels were associated with poor chemo-radiotherapy outcome.

CONCLUSIONS

HBO could re-sensitize radio-resistant OSCC cells through GPX4/ferroptosis regulation. These results provide a potential therapeutic strategy for clinical radio-resistance.

Effects of hyperbaric oxygen therapy on the morphological characteristics and survival of MCF-7 breast cancer cells

Aim: This study aims to determine the effects of hyperbaric oxygen therapy at different pressure values on cell morphology and cell survival in the MCF-7 breast cancer cell line. Materials and Methods: The experimental groups were formed by applying 100% oxygen to MCF-7 breast cancer cells at 1.5, 2, and 2.5 atmospheres for 2 hours. The control group did not receive treatment. At the end of the experiment, cell survival was investigated by CCK-8 analysis, cell shapes were determined by cresyl violet staining, and cell surface morphologies were determined by scanning electron microscope. Results: Cell viability was significantly reduced at atmospheric pressure of 1.5, 2, and 2.5 compared to the control group (p < 0.005). As pressure increased, the surface area of the cell decreased, nuclear condensation increased, and the cell borders became irregular. Cell membrane bleb and cell membrane porosity increased at 2 and 2.5 atmospheres. Conclusion: Hyperbaric oxygen therapy severely reduces the viability of MCF-7 breast cancer cells under increased pressure. It can induce apoptosis and change the shape and surface morphology of MCF-7 breast cancer cells. Although further studies are needed, our study supports the potential use of hyperbaric oxygen therapy in the treatment of breast cancer.

Effects of Hyperbaric Oxygen Therapy on the Morphological Characteristics and Survival of MCF-7 Breast Cancer Cells

Aim: This study aims to determine the effects of hyperbaric oxygen therapy at different pressure values on cell morphology and cell survival in the MCF-7 breast cancer cell line. Materials and Methods: The experimental groups were formed by applying 100% oxygen to MCF-7 breast cancer cells at 1.5, 2, and 2.5 atmospheres for 2 hours. The control group did not receive treatment. At the end of the experiment, cell survival was investigated by CCK-8 analysis, cell shapes were determined by crystal violet staining, and cell surface morphologies were determined by scanning electron microscope. Results: Cell viability was significantly reduced at atmospheric pressure of 1.5, 2, and 2.5 compared to the control group (p < 0.005). As pressure increased, the surface area of the cell decreased, nuclear condensation increased, and the cell borders became irregular. Cell membrane bleb and cell membrane porosity increased at 2 and 2.5 atmospheres. Conclusion: Hyperbaric oxygen therapy severely reduces the viability of MCF-7 breast cancer cells under increased pressure. It can induce apoptosis and change the shape and surface morphology of MCF-7 breast cancer cells. Although further studies are needed, our study supports the potential use of hyperbaric oxygen therapy in the treatment of breast cancer.

Mir-573 regulates cell proliferation and apoptosis by targeting Bax in human degenerative disc cells following hyperbaric oxygen treatment

Background

MicroRNA (miRNA) plays a vital role in the intervertebral disc (IVD) degeneration. The expression level of miR-573 was downregulated whereas Bax was upregulated notably in human degenerative nucleus pulposus cells. In this study, we aimed to investigate the role of miR-573 in human degenerative nucleus pulposus (NP) cells following hyperbaric oxygen (HBO) treatment.

Methods

NP cells were separated from human degenerated IVD tissues. The control cells were maintained in 5% CO₂/95% air and the hyperoxic cells were exposed to 100% O₂ at 2.5 atmospheres absolute. MiRNA expression profiling was performed via microarray and confirmed by real-time PCR, and miRNA target genes were identified using bioinformatics and luciferase reporter assays. The mRNA and protein levels of Bax were measured. The proliferation of NPCs was detected using MTT assay. The protein expression levels of Bax, cleaved caspase 9, cleaved caspase 3, pro-caspase 9, and pro-caspase 3 were examined.

Results

Bioinformatics analysis indicated that the 3′ untranslated region (UTR) of the Bax mRNA contained the “seed-matched-sequence” for hsa-miR-573, which was validated via reporter assays. MiR-573 was induced by HBO and simultaneous suppression of Bax was observed in NP cells. Knockdown of miR-573 resulted in upregulation of Bax expression in HBO-treated cells. In addition, overexpression of miR-573 by HBO increased cell proliferation and coupled with inhibition of cell apoptosis. The cleavage of pro-caspase 9 and pro-caspase 3 was suppressed while the levels of cleaved caspase 9 and caspase 3 were decreased in HBO-treated cells. Transfection with anti-miR-573 partly suppressed the effects of HBO.

Conclusion

Mir-573 regulates cell proliferation and apoptosis by targeting Bax in human degenerative NP cells following HBO treatment.

Hyperbaric oxygen rescues lung cancer cells from chemical hypoxia-induced low differentiation and apoptosis resistance

Hypoxia induces vigorous growth and a higher malignant phenotype in solid tumors. Hyperoxic treatment using hyperbaric oxygen (HBO) has previously been shown as a highly effective method to attenuate hypoxia. We aimed to investigate the effect of HBO on hypoxia-induced malignancy of lung cancer cells. Cobalt chloride (CoCl₂) was used to induce chemical hypoxia in lung cancer cell line A549. Hypoxic inducible factor-1α (HIF-1α) expression, lactate dehydrogenase (LDH) activity, migration and invasion capacity, expression profiles of epithelial-mesenchymal transition (EMT) markers and apoptotic markers were assessed in CoCl₂-treated A549 cells, with or without HBO treatment. Chemical hypoxia caused by CoCl₂ resulted in high LDH activity, increased migration and invasion, decreased E-cadherin/N-cadherin ratio, enhanced EMT phenotype, higher Bcl-2/Bax ratio and elevated GRP78 expression. HBO treatment could significantly attenuate hypoxia-induced LDH activity, migration and invasion, restore hypoxia-reduced E-cadherin/N-cadherin ratio and EMT phenotype, as well as hypoxia-induced Bcl-2/Bax ratio, and repress GRP78 expression. HBO could serve as a reliable adjuvant treatment targeting the hypoxia microenvironment in solid tumors.

Hyperbaric oxygen treatment sensitizes gastric cancer cells to melatonin-induced apoptosis through multiple pathways

Although extensive efforts have been made in recent decades to treat advanced gastric cancer with comprehensive therapy based on chemotherapy, effective anti-gastric cancer therapeutics are still lacking in the clinics. Therefore, potent novel anti-gastric cancer ways are greatly needed. Here, we explored hyperbaric oxygen treatment as a novel and effective adjuvant treatment method which has anti-gastric cancer effects when used together with melatonin. When performed together with MLT, HBO effectively inhibited tumorigenicity of gastric cancer through selectively inducing a robust tumor suppressive apoptosis response. Mechanistic studies revealed that the sensitizing effect of hyperbaric oxygen is due to decreased ratio of Bcl-2/Bax, increased level of p53, cleaved Caspase3, GRP78, CHOP, and LC3. These results give a vivid picture that classic apoptosis pathways including mitochondrial pathway, tumor suppressive endoplasmic reticulum stress (ERS), and autophagy are all involved in the process. From the preliminary results got from the current study, we identified that HBO sensitizes human gastric cancer cells to MLT-induced apoptosis through a variety of complicated molecular mechanisms. HBO may provide a novel candidate supplemental treatment method for further development of potential anti-gastric cancer therapeutics. The combination of HBO and MLT could be a promising treatment for advanced gastric cancer.