Overexpression of bHLH domain of HIF-1 failed to inhibit the HIF-1 transcriptional activity in hypoxia

Non-destructive and efficient method for obtaining miRNA information in cells by artificial extracellular vesicles

In recent years, research has explored the use of microRNA (miRNA) analysis in extracellular vesicles (EVs) as a minimally invasive strategy for the diagnosis and prediction of diseases. This is because miRNAs in EVs partly reflect the miRNA information and cellular status of the origin cells. However, not all intracellular miRNAs are internalized into EVs. Therefore, the miRNA information obtained from EVs is limited. To get more miRNA information, we aimed to produce artificial EVs (aEVs) encapsulating Argonaute 2 (Ago2) miRNA-binding protein, which actively incorporate miRNAs within themselves. In this study, we utilized the protein EPN-01, which is capable of releasing aEVs encapsulating it and associated proteins. This system enables us to obtain more miRNA species and increase each miRNA's yield in the EV fraction. Furthermore, we examined whether miRNAs in the EV fraction using our system reflect the cellular condition. In cells treated with CoCl2, a reagent for inducing a hypoxia-mimic state, we detected a change in the level of hypoxia marker miR-210 with aEVs. To the best of our knowledge, this is the first report on a method to increase the yield and variety of endogenous miRNAs in the EV fraction. This approach leads to improved accuracy of cell status assessment using miRNAs in EVs.

3, 3'-diindolylmethane, a natural aryl hydrocarbon receptor agonist, alleviates ulcerative colitis by enhancing "glycolysis-lactate-STAT3″ and TIP60 signals-mediated Treg differentiation

BACKGROUND

Aryl hydrocarbon receptor (AhR) plays an important role in the occurrence and development of ulcerative colitis (UC). In this study, the effect and mechanism of 3, 3'-diindolylmethane (DIM), the classical AhR agonist, on UC was investigated from the angle of recovering the balance of Th17/Treg.

METHODS

The in vivo colitis model was established in mice by using dextran sulfate sodium, and CD4+ T cells were used to simulate the in vitro differentiation of Treg and Th17 cells. The proportions and related factors of Th17 and Treg cells were measured using flow cytometry, Q-PCR and western blotting. The glycolysis was evaluated by examining the glucose uptake, glucose consumption and lactate production using kits or immunofluorescence. The activation of AhR was detected by western blotting and the XRE-luciferase reporter gene. The co-immunoprecipitation, transfection or other methods were selected to investigate and identify the signaling molecular pathway.

RESULTS

DIM significantly attenuated symptoms of colitis mice by rebuilding the balance of Th17/Treg in anoxic colons. In hypoxia, a more potent promotion of Treg differentiation was showed by DIM relative to normoxia, and siFoxp3 prevented DIM-suppressed Th17 differentiation. DIM repressed the excessive glycolysis in hypoxia evidenced by down-regulated glucose uptake, lactate production, Glut1 and HK2 levels. Interestingly, IL-10, the function-related factor of Treg cells, showed the feedback effect of DIM-suppressed glycolysis. Besides, 2-deoxy-D-glucose, HK2 plasmid and IL-10 antibody prevented increase of DIM on the expression of Foxp3 at the transcriptional level and subsequent Treg differentiation through the lactate-STAT3 pathway, and reasons for the direct improvement of DIM on Foxp3 protein was attributed to promoting the formation of HIF-1α/TIP60 complexes as well as subsequent acetylation and protein stability. Finally, AhR dependence and mechanisms for DIM-improved Treg differentiation in vitro and in vivo were well confirmed by using plasmids or inhibitors.

CONCLUSIONS

DIM enhances activation of AhR and subsequent "glycolysis-lactate-STAT3″ and TIP60 signals-mediated Treg differentiation.

Hypoxia effects on oncolytic virotherapy in Cancer: Friend or Foe?

Researchers have tried to find novel strategies for cancer treatment in the past decades. Among the utilized methods, administering oncolytic viruses (OVs) alone or combined with other anticancer therapeutic approaches has had promising outcomes, especially in solid tumors. Infecting the tumor cells by these viruses can lead to direct lysis or induction of immune responses. However, the immunosuppressive tumor microenvironment (TME) is considered a significant challenge for oncolytic virotherapy in treating cancer. Based on OV type, hypoxic conditions in the TME can accelerate or repress virus replication. Therefore, genetic manipulation of OVs or other molecular modifications to reduce hypoxia can induce antitumor responses. Moreover, using OVs with tumor lysis capability in the hypoxic TME may be an attractive strategy to overcome the limitations of the therapy. This review summarizes the latest information available in the field of cancer virotherapy and discusses the dual effect of hypoxia on different types of OVs to optimize available related therapeutic methods.

Hyaluronic acid coated nano-particles for H2O2-elevation augmented photo-/chemodynamic therapy

In recent years, the association of chemodynamic therapy (CDT) with photodynamic therapy (PDT) has attracted much attention due to their mutually reinforced property. Nevertheless, how to further strengthen their performance is still a big challenge. Given the PDT/CDT therapeutic mechanism, the H2O2 amount might affect their final performance. Thus, in this paper, our synthesized pH-responsive Fenton agents (ferrocene-cinnamaldehyde conjugates, Fc-CA) were encapsulated in hyaluronic acid (HA) coated porphyrin-based MOF to obtain supramolecular nano-particles (Fc-CA-PCN-HA). After the CD44-receptor mediated internalization, the released Fc-CA could further dissociate in the acidic pH micro-environment. The released CA can activate the NADPH oxidase to elevate the H2O2 amount which could be preferable to produce more ·OH through Fenton reaction for cancer cells apoptosis. Additionally, O2 was also generated in the CDT which could alleviate tumor hypoxia condition and be provided as the reactant for PDT to produce more 1O2. Thus, given the excellent cascade reactions induced therapeutic performance of Fc-CA-PCN-HA in vitro and in vivo, the H2O2-elevation strategy might further enhance the PDT/CDT outcomes.

Bioinformatics Identification of Regulatory Genes and Mechanism Related to Hypoxia-Induced PD-L1 Inhibitor Resistance in Hepatocellular Carcinoma

The combination of a PD-L1 inhibitor and an anti-angiogenic agent has become the new reference standard in the first-line treatment of non-excisable hepatocellular carcinoma (HCC) due to the survival advantage, but its objective response rate remains low at 36%. Evidence shows that PD-L1 inhibitor resistance is attributed to hypoxic tumor microenvironment. In this study, we performed bioinformatics analysis to identify genes and the underlying mechanisms that improve the efficacy of PD-L1 inhibition. Two public datasets of gene expression profiles, (1) HCC tumor versus adjacent normal tissue (N = 214) and (2) normoxia versus anoxia of HepG2 cells (N = 6), were collected from Gene Expression Omnibus (GEO) database. We identified HCC-signature and hypoxia-related genes, using differential expression analysis, and their 52 overlapping genes. Of these 52 genes, 14 PD-L1 regulator genes were further identified through the multiple regression analysis of TCGA-LIHC dataset (N = 371), and 10 hub genes were indicated in the protein-protein interaction (PPI) network. It was found that POLE2, GABARAPL1, PIK3R1, NDC80, and TPX2 play critical roles in the response and overall survival in cancer patients under PD-L1 inhibitor treatment. Our study provides new insights and potential biomarkers to enhance the immunotherapeutic role of PD-L1 inhibitors in HCC, which can help in exploring new therapeutic strategies.

Hypoxia disrupt tight junctions and promote metastasis of oral squamous cell carcinoma via loss of par3

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a highly malignant tumor that is frequently associated with lymph node metastasis, resulting in poor prognosis and survival in patients. In the tumor microenvironment, hypoxia plays an important role in regulating cellular responses such as progressive and rapid growth and metastasis. In these processes, tumor cells autonomously undergo diverse transitions and acquire functions. However, hypoxia-induced transition of OSCC and the involvement of hypoxia in OSCC metastasis remain unclear. Therefore, in this study, we aimed to elucidate the mechanism of hypoxia-induced OSCC metastasis and particularly, its impact on tight junctions (TJs).

METHODS

The expression of hypoxia-inducible factor 1-alpha (HIF-1α) was detected in tumor tissues and adjacent normal tissues from 29 patients with OSCC using reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry (IHC). The migration and invasion abilities of OSCC cell lines treated with small interfering (si)RNA targeting HIF-1α or cultured in hypoxic conditions were analyzed using Transwell assays. The effect of HIF-1α expression on in vivo tumor metastasis of OSCC cells was evaluated using lung metastasis model.

RESULTS

HIF-1α was overexpressed in patients with OSCC. OSCC metastasis was correlated with HIF-1α expression in OSCC tissues. Hypoxia increased the migration and invasion abilities of OSCC cell lines by regulating the expression and localization of partitioning-defective protein 3 (Par3) and TJs. Furthermore, HIF-1α silencing effectively decreased the invasion and migration abilities of OSCC cell lines and restored TJ expression and localization via Par3. The expression of HIF-1α was positively regulated the OSCC metastasis in vivo.

CONCLUSIONS

Hypoxia promotes OSCC metastasis by regulating the expression and localization of Par3 and TJ proteins. HIF-1α positively correlates to OSCC metastasis. Lastly, HIF-1α expression could regulate the expression of Par3 and TJs in OSCC. This finding may aid in elucidating the molecular mechanisms of OSCC metastasis and progression and developing new diagnostic and therapeutic approaches for OSCC metastasis.

Qing Zao Fang (QZF) Alleviates the Inflammatory Microenvironment of the Submandibular Gland in Sjögren's Syndrome Based on the PI3K/Akt/HIF-1α/VEGF Signaling Pathway

Sjögren's syndrome (SS) which could lead to a disorder of our immune system is a chronic autoimmune disease characterized by invading exocrine glands such as salivary glands and lacrimal glands and other exocrine glands. Its common symptom is dry mouth and dry eyes, often accompanied by a large number of lymphocyte infiltrations and can involve other organs to cause complex clinical manifestations. In this study, we aimed at investigating the effect of QZF in SS, identifying the molecular mechanism in modulating autoimmune response, and determining the important roles of these factors' function as a modulator in the pathogenesis of SS. The NOD mice were utilized to establish the rats' model of Sjögren's syndrome. After 10 weeks' hydroxychloroquine and QZF in different dose interference, submandibular gland tissue was collected. The therapeutic effect of QZF on SS rats was identified, and the results suggest the comparable potential to hydroxychloroquine. In submandibular gland tissue, interleukin- (IL-) 17 was significantly lower in high-dose QZF than that in SS rats and the focal lymphocytes were highly attenuated. Moreover, we found that PI3K/Akt signals were activated and the downstream HIF-1α/VEGF signals were enhanced in SS rats whose protein expression could be inhibited by QZF treatment. In addition, QZF could modulate autophagy in submandibular gland tissue and then inhibit the inflammation response and therefore facilitate the tissue repair.

Immune and metabolic checkpoints blockade: Dual wielding against tumors

Recent advances in cancer immunotherapy have raised hopes for treating cancers that are resistant to conventional therapies. Among the various immunotherapy methods, the immune checkpoint (IC) blockers were more promising and have paved their way to the clinic. Tumor cells induce the expression of ICs on the immune cells and derive them to a hyporesponsive exhausted phenotype. IC blockers could hinder immune exhaustion in the tumor microenvironment and reinvigorate immune cells for an efficient antitumor response. Despite the primary success of IC blockers in the clinic, the growing numbers of refractory cases require an in-depth study of the cellular and molecular mechanisms underlying IC expression and function. Immunometabolism is recently found to be a key factor in the regulation of immune responses. Activated or exhausted immune cells exploit different metabolic pathways. Tumor cells can suppress antitumor responses via immunometabolism alteration. Therefore, it is expected that concurrent targeting of ICs and immunometabolism pathways can cause immune cells to restore their antitumor activity. In this review, we dissected the reciprocal interactions of immune cell metabolism with expression and signaling of ICs in the tumor microenvironment. Recent findings on dual targeting of ICs and metabolic checkpoints have also been discussed.