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

Hyperbaric Oxygen Therapy as an Alternative Therapeutic Option for Radiation-Induced Necrosis Following Radiotherapy for Intracranial Pathologies

BACKGROUND

Radiotherapy (RT) is a feasible adjuvant therapeutic option for managing intracranial pathologies. One of the late complications of RT that frequently develops within months following RT is radiation necrosis (RN). Corticosteroids are the first-line therapeutic option for RNs; however, in case of unfavorable outcomes or intolerability, several other options, including bevacizumab, laser interstitial thermal therapy, surgery, and hyperbaric oxygen therapy (HBOT). Our goal was to investigate the feasibility and efficacy of the application of HBOT in RNs following RT and help physicians make decisions based on the latest data in the literature.

METHODS

We provide a comprehensive review of the literature on the current issues of utilization of HBOT in RNs.

RESULTS

We included 11 studies with a total of 46 patients who underwent HBOT. Most of the cases were diagnosed with brain tumors or arteriovenous malformations. Improvement was achieved in most of the cases.

DISCUSSION

HBOT is a noninvasive therapeutic intervention that can play a role in adjuvant therapy concurrent with RT and chemotherapy and treating RNs. HBOT resolves the RN through 3 mechanisms, including angiogenesis, anti-inflammatory modulation, and cellular repair. Previous studies demonstrated that HBOT is a feasible and well-tolerated therapeutic option that has shown promising results in improving clinical and radiological outcomes in intracranial RNs. Complications of HBOT are usually mild and reversible.

CONCLUSIONS

HBOT is a feasible and effective therapeutic option in steroid-refractory RNs and is associated with favorable outcomes and a low rate of side effects.

Radioiodine-131-Labeled Theranostic Nanoparticles for Transarterial Radioembolization and Chemoembolization Combination Therapy of VX2 Liver Tumor

In interventional treatment, materials are administered into the blood supply artery and directly delivered to tumors, offering proper scenarios for nanomedicine potential clinical applications. Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are effective treatment methods for hepatocellular carcinoma (HCC), but postoperative residual tumor may result in intrahepatic recurrence and distant metastasis. The combination therapy of TACE and TARE based on multifunctional nanoparticles (NPs) is expected to overcome the drug resistance in hypoxic tumors and improve the therapeutic effect. Herein, BaGdF5 NPs are synthesized and then coated with polydopamine (PDA), conjugated with the chemotherapeutic drug cis-diamminedichloride platinum (CDDP), radio-labeled with therapeutic radionuclide 131 I, yielding 131 I-BaGdF5 @PDA-CDDP NPs. The in vitro anti-cancer effects of 131 I-BaGdF5 @PDA-CDDP NPs are confirmed using CCK-8 and γ-H2AX assays in Huh7 cells. Mixed with Lipiodol, 131 I-BaGdF5 @PDA-CDDP NPs are injected into the hepatic artery via a microcatheter to realize the TACE and TARE combination therapy in a rabbit VX2 liver tumor model. The results indicate that glucose metabolism is clearly decreased based on 18 F-FDG PET imaging and the apoptosis of tumor cells is increased. Furthermore, 131 I and BaGdF5 NPs can be used for SPECT imaging and CT/MR imaging respectively, facilitating real-time monitoring of the in vivo biodistribution of 131 I-BaGdF5 @PDA-CDDP NPs.

Reduced HIF-1α Stability Induced by 6-Gingerol Inhibits Lung Cancer Growth through the Induction of Cell Death

Lung cancer (LC) is the leading global cause of cancer-related death, and metastasis is a great challenge in LC therapy. Additionally, solid cancer, including lung, prostate, and colon cancer, are characterized by hypoxia. A low-oxygen state is facilitated by the oncogene pathway, which correlates with a poor cancer prognosis. Thus, we need to understand the related mechanisms in solid tumors to improve and develop new anticancer strategies. The experiments herein describe an anticancer mechanism in which heat shock protein 90 (HSP90) stabilizes HIF-1α, a master transcription factor of oxygen homeostasis that has been implicated in the survival, proliferation and malignant progression of cancers. We demonstrate the efficacy of 6-gingerol and the molecular mechanism by which 6-gingerol inhibits LC metastasis in different oxygen environments. Our results showed that cell proliferation was inhibited after 6-gingerol treatment. Additionally, HIF-1α, a transcriptional regulator, was found to be recruited to the hypoxia response element (HRE) of target genes to induce the transcription of a series of target genes, including MMP-9, vimentin and snail. Interestingly, we found that 6-gingerol treatment suppressed activation of the transcription factor HIF-1α by downregulating HSP90 under both normoxic and hypoxic conditions. Furthermore, an experiment in an in vivo xenograft model revealed decreased tumor growth after 6-gingerol treatment. Both in vitro and in vivo analyses showed the inhibition of metastasis through HIF-1α/HSP90 after 6-gingerol treatment. In summary, our study demonstrates that 6-gingerol suppresses proliferation and blocks the nuclear translocation of HIF-1α and activation of the EMT pathway. These data suggest that 6-gingerol is a candidate antimetastatic treatment for LC.

Turn-on silicon-based fluorescent probe for visualizing endogenous CO during hypoxia

A turn-on fluorescent probe for the fast imaging of endogenous CO has been developed and applied under different stimuli and hypoxia.

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.

Molecular Chaperones in Cancer Stem Cells: Determinants of Stemness and Potential Targets for Antitumor Therapy

Cancer stem cells (CSCs) are a great challenge in the fight against cancer because these self-renewing tumorigenic cell fractions are thought to be responsible for metastasis dissemination and cases of tumor recurrence. In comparison with non-stem cancer cells, CSCs are known to be more resistant to chemotherapy, radiotherapy, and immunotherapy. Elucidation of mechanisms and factors that promote the emergence and existence of CSCs and their high resistance to cytotoxic treatments would help to develop effective CSC-targeting therapeutics. The present review is dedicated to the implication of molecular chaperones (protein regulators of polypeptide chain folding) in both the formation/maintenance of the CSC phenotype and cytoprotective machinery allowing CSCs to survive after drug or radiation exposure and evade immune attack. The major cellular chaperones, namely heat shock proteins (HSP90, HSP70, HSP40, HSP27), glucose-regulated proteins (GRP94, GRP78, GRP75), tumor necrosis factor receptor-associated protein 1 (TRAP1), peptidyl-prolyl isomerases, protein disulfide isomerases, calreticulin, and also a transcription heat shock factor 1 (HSF1) initiating HSP gene expression are here considered as determinants of the cancer cell stemness and potential targets for a therapeutic attack on CSCs. Various approaches and agents are discussed that may be used for inhibiting the chaperone-dependent development/manifestations of cancer cell stemness.

Hydrogen sulfide modulates epithelial-mesenchymal transition and angiogenesis in non-small cell lung cancer via HIF-1α activation

Hydrogen sulfide (H₂S) has been frequently implicated in tumor progression. However, the exact regulation mechanism of H₂S in human non-small cell lung cancer (NSCLC) has not been fully elucidated. Here, analysis of NSCLC biopsies and adjacent non-tumor tissues revealed selectively high levels of endogenous H₂S-producing enzymes, cystathionine-beta-synthase (CBS), cystathionine-gamma-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (MPST). Similarly, quantitative real-time PCR (qRT-PCR) and western blot results showed that NSCLC cell lines (A549, 95D) expressed higher levels of CBS, CSE and MPST in mRNA and enzyme proteins, respectively. Moreover, NSCLC cell lines produced more H₂S than did the normal lung epithelial cell line BEAS-2B. H₂S was further detected to induce NSCLC migration and invasion, as well as the epithelial mesenchymal transition (EMT) process. Small interfering RNA (siRNA) silencing of CBS or CSE activity reduced proliferation and metastasis potential of tumor cells. In addition, H₂S modulated hypoxia-inducible factor-1α (HIF-1α) to stimulate vascular endothelial growth factor (VEGF) expression, which contributes to tumor angiogenesis. Treatment of nude mice with pharmacological inhibition of CBS or CSE activity decreased xenograft growth and suppressed angiogenesis. Collectively, these results indicate H₂S plays an important part in NSCLC growth and angiogenesis by HIF-1α activation, which potentially provide new insight in therapeutic strategies.