Role of hyperoxic treatment in cancer

Spatiotemporal oxygen dynamics in young leaves reveal cyclic hypoxia in plants

Oxygen is essential for plant growth and development. Hypoxia occurs in plants due to limited oxygen availability following adverse environmental conditions as well in hypoxic niches in otherwise normoxic environments. However, the existence and functional integration of spatiotemporal oxygen dynamics with plant development remains unknown. In animal systems dynamic fluctuations in oxygen availability are known as cyclic hypoxia. In this study, we demonstrate that cyclic fluctuations in internal oxygen levels occur in young emerging leaves of Arabidopsis plants. Cyclic hypoxia in plants is based on a mechanism requiring the ETHYLENE RESPONSE FACTORS type VII (ERFVII) that are central components of the oxygen-sensing machinery in plants. The ERFVII-dependent mechanism allows precise adjustment of leaf growth in response to carbon status and oxygen availability within plant cells. This study thus establishes a functional connection between internal spatiotemporal oxygen dynamics and developmental processes of plants.

Protective effect of intermittent hypobaric hypoxia against radiation-induced liver damage in Sprague-Dawley rats

BACKGROUND

Without timely and effective interventions or treatments, radiation-induced liver damage (RILD) can lead to serious consequences for the patients and their families.

OBJECTIVE

To investigate the protective effect of intermittent hypobaric hypoxia preconditioning (IHHP) in RILD.

METHODS

Male adult SD rats were randomly divided into 8 groups including one control group, one only irradiation group and other experimental groups. Blood routine tests and liver function tests were all assessed with abdominal venous blood. Moreover, hematoxylin eosin (HE) staining and immunohistochemistry assay were used to detect the histopathological changes and expressions of transforming growth factor-β1 (TGF-β1), tumor necrosis factor α (TNF-α) and hypoxia-inducible factor 1α (HIF-1α) in radiated liver sections.

RESULTS

Blood routing tests showed that RBC, WBC and Hb were all significantly increased while the differences of these results between different groups with same simulated altitude were approximate. However, liver function in the IHHP plus irradiation at 4000 m group was significantly decreased (P< 0.05) compared to only irradiation groups, and the manifestation of HE and lower positive expression of TNF-α showed improved histopathological changes in the liver section. Furthermore, no significant difference of HIF-1α expression between any two groups treated with IHHP was observed.

CONCLUSION

IHHP at the altitude of 4000 m group could alleviate the radioactive liver damage by downregulating TNF-α and less strong positive expression of TGF-β1. Furthermore, patients exposed to radiation might benefit from this treatment to prevent or reduce the RILD.

Comparison effects of Ferula gummosa essential oil and Beta-pinene Alginate nanoparticles on human melanoma and breast cancer cells proliferation and apoptotic index in short term normobaric hyperoxic model

BACKGROUND

Breast cancer is the most common cancer among women, and melanoma is the most dreadful type of skin cancer. Due to the side effects of chemotherapy drugs, the development of new herbal nano-medicines has been considered.

METHODS

This study first investigated the chemical composition of Ferula gummosa essential oil using GC-MS analysis; β-pinene, with 61.57%, was the major compound. Next, alginate nanoparticles containing β-pinene and the essential oil with particle sizes of 174 ± 7 and 137 ± 6 nm were prepared. Meanwhile, their zeta potentials were 12.4 ± 0.7 and 28.1 ± 1 mV. Besides, the successful loading of β-pinene and the essential oil in nanoparticles was confirmed using ATR-FTIR analysis. After that, their effects on viability and apoptotic index of human melanoma and breast cancer cells were investigated in normoxia and normobaric hyperoxia (NBO) conditions.

RESULTS

The best efficacy on A-375 and MDA-MB-231 cells was achieved by alginate nanoparticles containing the EO at hyperoxic and normoxia conditions; IC50 76 and 104 µg/mL. Besides, it affected apoptosis-involved genes; as Bax/Bcl-2 ratio was higher than 1, conditions for induction of apoptosis were obtained. Higher sensitivity was observed in the A-375 cell line treated with Alg-EO in the NBO model.

CONCLUSIONS

Alginate nanoparticles containing F. gummosa EO could be considered for further investigation in anticancer studies. Also, it may be expected that NBO can be a new strategy for delaying cancer progression and improving nanotherapy efficacy.

Hypoxia signaling in cancer: Implications for therapeutic interventions

Hypoxia is a persistent physiological feature of many different solid tumors and a key driver of malignancy, and in recent years, it has been recognized as an important target for cancer therapy. Hypoxia occurs in the majority of solid tumors due to a poor vascular oxygen supply that is not sufficient to meet the needs of rapidly proliferating cancer cells. A hypoxic tumor microenvironment (TME) can reduce the effectiveness of other tumor therapies, such as radiotherapy, chemotherapy, and immunotherapy. In this review, we discuss the critical role of hypoxia in tumor development, including tumor metabolism, tumor immunity, and tumor angiogenesis. The treatment methods for hypoxic TME are summarized, including hypoxia-targeted therapy and improving oxygenation by alleviating tumor hypoxia itself. Hyperoxia therapy can be used to improve tissue oxygen partial pressure and relieve tumor hypoxia. We focus on the underlying mechanisms of hyperoxia and their impact on current cancer therapies and discuss the prospects of hyperoxia therapy in cancer treatment.

Peroxide mediated oxygen delivery in cancer therapy

Hypoxia is a serious obstacle in cancer treatment. The aberrant vascular network as well as the abnormal extracellular matrix arrangement results in formation of a hypoxic regions in tumors which show high resistance to the curing. Hypoxia makes the cancer treatment challengeable via two mechanisms; first and foremost, hypoxia changes the cell metabolism and leads the cells towards an aggressive and metastatic phenotype and second, hypoxia decreases the efficiency of the various cancer treatment modalities. Most of the cancer treatment methods including chemotherapy, radiotherapy, photodynamic therapy, sonodynamic therapy and immunotherapy are negatively affected by the oxygen deprivation. Therefore, the regional oxygenation is requisite to alleviate the negative impacts of the hypoxia on tumor cells and tumor therapy modalities. A great deal of effort has been put forth to resolve the problem of hypoxia in tumors. Peroxides have gained tremendous attention as oxygen generating components in cancer therapy. The concurrent loading of the peroxides and cancer treatment components into a single delivery system can bring about a multipurpose delivery system and substantially encourage the success of the cancer amelioration. In this review, we have tried to after the description of a relation between hypoxia and cancer treatment modalities, discuss the role of peroxides in tumor hyperoxygenation and cancer therapy success. Thereafter, we have summarized a number of vehicles for the delivery of the peroxide alone or in combination with other therapeutic components for cancer treatment.

Implications of Hyperoxia over the Tumor Microenvironment: An Overview Highlighting the Importance of the Immune System

Hyperoxia is used in order to counteract hypoxia effects in the TME (tumor microenvironment), which are described to boost the malignant tumor phenotype and poor prognosis. The reduction of tumor hypoxic state through the formation of a non-aberrant vasculature or an increase in the toxicity of the therapeutic agent improves the efficacy of therapies such as chemotherapy. Radiotherapy efficacy has also improved, where apoptotic mechanisms seem to be implicated. Moreover, hyperoxia increases the antitumor immunity through diverse pathways, leading to an immunopermissive TME. Although hyperoxia is an approved treatment for preventing and treating hypoxemia, it has harmful side-effects. Prolonged exposure to high oxygen levels may cause acute lung injury, characterized by an exacerbated immune response, and the destruction of the alveolar-capillary barrier. Furthermore, under this situation, the high concentration of ROS may cause toxicity that will lead not only to cell death but also to an increase in chemoattractant and proinflammatory cytokine secretion. This would end in a lung leukocyte recruitment and, therefore, lung damage. Moreover, unregulated inflammation causes different consequences promoting tumor development and metastasis. This process is known as protumor inflammation, where different cell types and molecules are implicated; for instance, IL-1β has been described as a key cytokine. Although current results show benefits over cancer therapies using hyperoxia, further studies need to be conducted, not only to improve tumor regression, but also to prevent its collateral damage.

Survival benefit of thermal ablation combined with chemotherapy for the treatment of stage IV nonsmall cell lung cancer: a propensity-matched analysis

OBJECTIVE

To investigate the survival benefit of thermal ablation (TA) plus chemotherapy for Stage-IV nonsmall cell lung cancer (NSCLC).

METHODS

From the Surveillance, Epidemiology and End Results (SEER) database, data of Stage-IV NSCLC patients receiving different treatment modalities (TA plus chemotherapy vs. chemotherapy) from 2004 to 2016 were retrospectively analyzed using propensity-score matching (PSM) for covariates. Kaplan-Meier curves and the log-rank test for intergroup comparison of overall survival (OS) and lung cancer-specific survival (LCSS) and subgroup analyses in the PSM cohort evaluated possible survival benefits. Cox proportional risk models evaluated independent prognostic factors.

RESULTS

Among 52,574 patients, 152 received TA plus chemotherapy. After PSM, the TA plus chemotherapy and chemotherapy groups included 150 and 445 patients, respectively. Compared to the chemotherapy group, the TA plus chemotherapy group had better OS (p = 0.042) and LCSS (p = 0.031), especially in patients aged 70 and older in age-stratified subgroup analysis; no statistically significant beneficial trend was noted for patients younger than 70 years. Subgroup analysis by tumor size showed superior OS and LCSS with TA plus chemotherapy than chemotherapy for tumors ≤3.0 cm; however, no significant difference was found in subgroups with larger tumors. Multivariate analysis showed that TA plus chemotherapy was an independent prognostic factor for OS and LCSS (hazard ratio 0.70 [95% confidence interval 0.59-0.84] and 0.70 [0.58-0.84], respectively; p < 0.001).

CONCLUSION

TA plus chemotherapy is a potential treatment option for Stage-IV NSCLC, especially for patients aged 70 or older with tumor size ≤3 cm.

A General Overview on the Hyperbaric Oxygen Therapy: Applications, Mechanisms and Translational Opportunities

Hyperbaric oxygen therapy (HBOT) consists of using of pure oxygen at increased pressure (in general, 2-3 atmospheres) leading to augmented oxygen levels in the blood (Hyperoxemia) and tissue (Hyperoxia). The increased pressure and oxygen bioavailability might be related to a plethora of applications, particularly in hypoxic regions, also exerting antimicrobial, immunomodulatory and angiogenic properties, among others. In this review, we will discuss in detail the physiological relevance of oxygen and the therapeutical basis of HBOT, collecting current indications and underlying mechanisms. Furthermore, potential areas of research will also be examined, including inflammatory and systemic maladies, COVID-19 and cancer. Finally, the adverse effects and contraindications associated with this therapy and future directions of research will be considered. Overall, we encourage further research in this field to extend the possible uses of this procedure. The inclusion of HBOT in future clinical research could be an additional support in the clinical management of multiple pathologies.

Hyperbaric Oxygen Therapy Represses the Warburg Effect and Epithelial-Mesenchymal Transition in Hypoxic NSCLC Cells via the HIF-1α/PFKP Axis

BACKGROUND

Tumor cells initiate hypoxia-induced mechanisms to fuel cell proliferation, invasion, and metastasis, largely mediated by low O2-responsive Hypoxia-Inducible Factor 1 Alpha (HIF-1α). Therefore, hyperbaric oxygen therapy (HBO) is now being studied in cancer patients, but its impact upon non-small-cell lung cancer (NSCLC) cell metabolism remains uncharacterized.

METHODS

We employed the NSCLC cell lines A549 and H1299 for in vitro studies. Glucose uptake, pyruvate, lactate, and adenosine triphosphate (ATP) assays were used to assess aerobic glycolysis (Warburg effect). A quantitative glycolytic flux model was used to analyze the flux contributions of HIF-1α-induced glucose metabolism genes. We used a Lewis lung carcinoma (LLC) murine model to measure lung tumorigenesis in C57BL/6J mice.

RESULTS

HBO suppressed hypoxia-induced HIF-1α expression and downstream HIF-1α signaling in NSCLC cells. One HIF-1α-induced glucose metabolism gene-Phosphofructokinase, Platelet (PFKP)-most profoundly enhanced glycolytic flux under both low- and high-glucose conditions. HBO suppressed hypoxia-induced PFKP transactivation and gene expression via HIF-1α downregulation. HBO's suppression of the Warburg effect, suppression of hyperproliferation, and suppression of epithelial-to-mesenchymal transition (EMT) in hypoxic NSCLC cell lines is mediated by the HIF-1α/PFKP axis. In vivo, HBO therapy inhibited murine LLC lung tumor growth in a Pfkp-dependent manner.

CONCLUSIONS

HBO's repression of the Warburg effect, repression of hyperproliferation, and repression of EMT in hypoxic NSCLC cells is dependent upon HIF-1α downregulation. HIF-1α's target gene PFKP functions as a central mediator of HBO's effects in hypoxic NSCLC cells and may represent a metabolic vulnerability in NSCLC tumors.

Immunotherapy Using Oxygenated Water and Tumor-Derived Exosomes Potentiates Antitumor Immune Response and Attenuates Malignancy Tendency in Mice Model of Breast Cancer

Breast cancer is one of the most common type of tumor and the leading cause of death in the world's female population. Various therapeutic approaches have been used to treat tumors but have not led to complete recovery and have even damaged normal cells in the body. Moreover, metastatic tumors such as breast cancer are much more resistant to treatment, and current treatments have not been very successful in treating them and remain a challenge. Therefore, new approaches should be applied to overcome this problem. Given the importance of hypoxia in tumor survival, we aimed to test the antitumor effects of oxygenated water to decrease hypoxia along with tumor-derived exosomes to target tumor. The purpose of administering oxygenated water and tumor exosomes was to reduce hypoxia and establish an effective immune response against tumor antigens, respectively. For this purpose, the breast cancer mice model was induced using the 4T1 cell line in Balb/c mice and treated with oxygenated water via an intratumoral (IT) and/or intraperitoneal (IP) route and/or exosome (TEX). Oxygenation via the IT+IP route was more efficient than oxygenation via the IT or IP route. The efficiency of oxygenation via the two routes along with TEX led to the best therapeutic outcome. Antitumor immune responses directed by TEX became optimized when systemic (IP) and local (IT) oxygenation was applied compared to administration of TEX alone. Results demonstrated a significant reduction in tumor size and the highest levels of IFN-γ and IL-17 and the lowest levels of IL-4 FoxP3, HIF-1α, VEGF, MMP-2, and MMP-9 in the IT+IP+TEX-treated group. Oxygenated water on the one hand could reduce tumor size, hypoxia, angiogenesis, and metastasis in the tumor microenvironment and on the other hand increases the effective immune response against the tumor systemically. This therapeutic approach is proposed as a new strategy for devising vaccines in a personalized approach.