Intermittent hypoxia alleviates increased VEGF and pro-angiogenic potential in liver cancer cells

A colorimetric immunoassay for the detection of human vascular endothelial growth factor 165 (VEGF165) based on anti-VEGF-iron oxide nanoparticle conjugation

Vascular endothelial growth factor (VEGF) is an indispensable element in many physiological processes, while alterations in its level in the circulating system are signs of pathology-associated diseases. Therefore, its precise and selective detection is critical for clinical applications to monitor the progression of the pathology. In this study, an optical immunoassay biosensor was developed as a model study for detecting recombinant VEGF165. The VEGF165 sample was purified from recombinant Kluyveromyces lactis GG799 yeast cells. Indirect ELISA was used during the detection, wherein iron oxide nanoparticles (FeNPs) were utilized to obtain optical signals. The FeNPs were synthesized in the presence of lactose p-amino benzoic acid (LpAB). VEGF165 antibody was conjugated to the LpAB-FeNPs through EDC/NHS chemistry to convert the iron oxide nanoparticles into VEGF165 specific probes. The specificity of the prepared system was tested in the presence of potential serum-based interferents (i.e., glucose, urea, insulin, C-reactive protein, and serum amyloid A), and validation studies were performed in a simulated serum sample. The proposed immunoassay showed a wide detection range (0.5 to 100 ng/mL) with a detection limit of 0.29 ng/mL. These results show that the developed assay could offer a sensitive, simple, specific, reliable, and high-throughput detection platform that can be used in the clinical diagnostics of VEGF.

Engineering Platelet Membrane Imitating Nanoparticles for Targeted Therapeutic Delivery

Platelet Membrane Imitating Nanoparticles (PMINs) is a novel drug delivery system that imitates the structure and functionality of platelet membranes. PMINs imitate surface markers of platelets to target specific cells and transport therapeutic cargo. PMINs are engineered by incorporating the drug into the platelet membrane and encapsulating it in a nanoparticle scaffold. This allows PMINs to circulate in the bloodstream and bind to target cells with high specificity, reducing off-target effects and improving therapeutic efficacy. The engineering of PMINs entails several stages, including the separation and purification of platelet membranes, the integration of therapeutic cargo into the membrane, and the encapsulation of the membrane in a nanoparticle scaffold. In addition to being involved in a few pathological conditions including cancer, atherosclerosis, and rheumatoid arthritis, platelets are crucial to the body's physiological processes. This study includes the preparation and characterization of platelet membrane-like nanoparticles and focuses on their most recent advancements in targeted therapy for conditions, including cancer, immunological disorders, atherosclerosis, phototherapy, etc. PMINs are a potential drug delivery system that combines the advantages of platelet membranes with nanoparticles. The capacity to create PMMNs with particular therapeutic cargo and surface markers provides new possibilities for targeted medication administration and might completely change the way that medicine is practiced. Despite the need for more studies to optimize the engineering process and evaluate the effectiveness and safety of PMINs in clinical trials, this technology has a lot of potential.

Short-term changes of angiogenesis factors after transarterial radioembolization in hepatocellular carcinoma patients

PURPOSE

To analyze changes in angiogenesis factors after transarterial radioembolization (TARE) with Yttrium- 90-loaded resin microspheres in hepatocellular carcinoma (HCC) patients.

METHODS

Interleukin-6, interleukin-8, hepatocyte growth factor, platelet-derived growth factor, fibroblast growth factor, vascular endothelial growth factor-A (VEGF-A), and angiopoietin-2 levels in 26 patients were measured before TARE and on day 1, 7, 14, and 30 after TARE and evaluated regarding radiological response.

RESULTS

In the sixth month of follow-up, 11 (42.30%) patients had a complete or partial response to treatment, while progressive disease was found in 15 (57.69%) patients. The percentage changes in VEGF-A in the non-responders on day 30 (P = 0.034) after TARE were significantly more obvious. Peak formation rates of VEGF-A were higher in non-responders (P = 0.036).

CONCLUSION

Short-term changes in angiogenesis factors in HCC patients after TARE with Yttrium-90-loaded resin microspheres fluctuate with different amplitudes at different times. The upregulation of growth factors has a prognostic capacity. Changes in VEGF-A after TARE may be helpful for the early recognition of non-responders.

Incidence disparities of obstructive sleep apnea-associated lung cancer by gender; Korean National Health Insurance data analysis

Introduction

Obstructive sleep apnea (OSA) is known to increase the risk of various cancers. By analyzing the Korea National Health Insurance Service (KNHIS) registry, the impact of OSA on the lung cancer incidence was analyzed in a retrospective cohort group.

Methods

A retrospective cohort of adult patients newly registered with OSA in the KNHIS data from 2007 to 2017 was included and observed until December 2019 (12 years). The main outcome measure was newly diagnosed lung cancer. The control group was set with age and sex that matched those in the OSA group.

Results

The hazard ratio (HR) of OSA for lung cancer incidence showed a significantly reduced HR of 0.87 (95% CI, 0.82-0.93). The observed significance of this finding was limited to male OSA patients [HR, 0.84 (95% CI, 0.78-0.90)], while no significant association was found in female OSA patients [HR, 1.05 (95% CI, 0.91-1.21)], irrespective of their age.

Discussion

OSA patients have a lower risk of developing lung cancer, but this risk reduction is gender-specific, as female OSA patients do not show a reduction in hazard ratio.

Is acriflavine an efficient co-drug in chemotherapy?

Cancer is a global health problem being the second worldwide cause of deaths right after cardiovascular diseases. The main methods of cancer treatment involve surgery, radiation and chemotherapy with an emphasis on the latter. Thus development of nanochemistry and nanomedicine in a search for more effective and safer cancer treatment is an important area of current research. Below, we present interaction of doxorubicin and acriflavine and the cytotoxicity of these drug nano-complexes towards cervical cancer (HeLa) cells. Experimental results obtained from NMR measurements and fluorescence spectroscopy show that the drugs' interaction was due to van der Waals forces, formation of hydrogen bonds and π-π stacking. Quantum molecular simulations confirmed the experimental results with regard to existing π-π stacking. Additionally it was shown that, at the level of theory applied (DFT, triple zeta basis set), the stacking interactions comprise the most preferable interactions (the lowest ΔG ca. -12 kcal mol^-1) both between the molecules forming the acriflavine system and between the other component - another drug (doxorubicin) dimer. Biological tests performed on HeLa cells showed high cytotoxicity of the complexes, comparable to free drugs (ACF and DOX), both after 24 and 48 hours of incubation. For non-cancerous cells, a statistically significant difference in the cytotoxicity of drugs and complexes was observed in the case of a short incubation period. The results of the uptake study showed significantly more efficient cellular uptake of acriflavine than doxorubicin, whether administered alone or in combination with an anthracycline. The mechanism determining the selective uptake of acriflavine and ACF : DOX complexes towards non-cancer and cancer cells should be better understood in the future, as it may be of key importance in the design of complexes with toxic anti-cancer drugs.

Triptolide Inhibits the Biological Processes of HUVECs and HepG2 Cells via the Serine Palmitoyltransferase Long Chain Base Subunit 2/Sphingosine-1-Phosphate Signaling Pathway

Triptolide (TP) has demonstrated innumerous biological effects and pharmacological potential against different cancer types. Hepatocellular carcinoma has a high incidence in men, and its incidence is increasing year by year. Studies have shown that angiogenesis plays an important role in the formation of tumors and that angiogenesis is closely related to tumor growth and metastasis. Deregulation of sphingolipids signaling has been associated with several pathological conditions, including cancer. In the present study, we aimed at exploring the potential molecular mechanism of TP’s antivascular and antitumor effects in vitro from the perspective of sphinolipids. Human umbilical vein endothelial cells (HUVECs) and HepG2 cells were, respectively, treated with different concentrations of TP and transfected. Then, the effect of HUVECs on HepG2 cells was investigated using a three-dimensional coculture model system. CCK-8 assay was performed for cell proliferation. Cell migration and invasion abilities were assessed using the transwell assay. Cell adhesion and tube formation were detected by Matrigel. RT-PCR and western blotting were used to detect the mRNA and protein expression. The S1P production was measured via ELISA assay. Our results showed that TP inhibited HUVECs and HepG2 cells proliferation, migration, invasion, adhesion, angiogenesis, and serine palmitoyltransferase long chain base subunit 2 (SPTLC2) expression; upregulating SPTLC2 facilitated the proliferation, migration, invasion, adhesion, angiogenesis, and sphingosine-1-phosphate (S1P) production of HUVECs and HepG2 cells, while interfering with SPTLC2 expression inhibited them; HUVECs facilitated the proliferation, migration, invasion, S1P production, S1PR1, and S1PR2 expression of HepG2 cells, while S1PR3 expression was decreased. In conclusion, SPTLC2 may be associated with the antivascular and antitumor effects of TP, and SPTLC2 is expected to become a new marker for tumor therapy. HUVECs can promote the proliferation, migration, and invasion of HepG2 cells, which may be related to the S1P/sphingosine-1-phosphate receptor (S1PR) signaling pathway.

A Comparative Study of Serum Angiogenic Biomarkers in Cirrhosis and Hepatocellular Carcinoma

Simple Summary

The progression of liver disease is accompanied by pathological angiogenesis, a prerequisite for the development of HCC. In this paper, we analyzed the clinical significance of serum angiogenic markers VEGF, Ang-1, Ang-2, angiopoietin receptor Tie1/2, HGF, and PECAM-1 in 62 patients with liver disease, out of which 33 were diagnosed with HCC and 29 with liver cirrhosis without signs of neoplasia. Biomarkers levels were investigated as a function of “Model for End-Stage Liver Disease” (MELD) score and Fibrosis Index (FI). HCC patients showed higher HGF levels than ones with cirrhosis, while high Ang-1 levels appeared to have a protective role in HCC as well as prognostic significance; we also found a strong correlation between HGF levels, Ang-2, and VEGF levels, further supporting their role in tumor angiogenesis. Due to the complexity of angiogenesis and the small size of the study group, further investigations are widely desired especially in the era of immunotherapy and HCC-targeted anti-angiogenic drugs.

Abstract

Background: Hepatocellular carcinoma (HCC) is a global health problem associated with chronic liver disease. Its pathogenesis varies according to the underlying etiological factors, although in most cases it develops from liver cirrhosis. The disease progression is accompanied by pathological angiogenesis, which is a prerequisite that favors the development of HCC. Aims: This study aims at contributing to our understanding of the role of angiogenic factors in the progression of liver disease. For this purpose, we evaluate the clinical significance of serum angiogenic markers (VEGF, Ang-1, Ang-2, the angiopoietin receptor Tie1/2, HGF, and PECAM-1) first in cirrhotic and HCC patients separately, and then comparing cirrhotic patients with and without HCC. Materials and Methods: We enrolled 62 patients, out of whom 33 were diagnosed with HCC and 29 with liver cirrhosis without signs of neoplasia. Patients underwent venous blood sampling before and after receiving treatments for the diagnosed disease. Serum markers were evaluated using ELISA assays for Tie1 and the Bio-Plex Multiplex system for the remaining ones. Biomarker levels were investigated as a function of clinical scores for disease staging (MELD and Fibrosis Index, FI). Results: In cirrhotic patients, Ang-1 and Ang-2 correlate with MELD (ρ_Ang-1 = −0.73, p = 2E−5) and FI (ρ_Ang-1 = −0.52, p = 7E−3, ρ_Ang-2 = 0.53, p = 3E−3). A reduction of Ang-2 levels (p = 0.047) and of the Ang-2/Ang-1 ratio (p = 0.031) is observed in cirrhotic patients diagnosed with viral hepatitis after antiviral treatments. In HCC patients, Ang-1 negatively correlates with FI (ρ = −0.63, p = 1E−4), and PECAM-1 positively correlates with MELD (ρ = 0.44, p = 0.01). A significant Ang-1 reduction was observed in deceased patients during the study compared to ones who survived (p = 0.01). In HCC patients, VEGF levels were increased after tumor treatment (p = 0.037). Notably, HGF levels in cirrhotic patients with HCC are significantly raised (p = 0.017) compared to that in those without HCC. Conclusions: Our results suggest that serum angiogenic markers, with emphasis on Ang-1/2, can contribute to the development of quantitative tools for liver disease staging and therapy monitoring. The comparison between cirrhotic patients with and without HCC suggests that HGF levels are potentially useful for monitoring the insurgence of HCC after a cirrhosis diagnosis. High Ang-1 levels in HCC patients appear to have a protective role as well as prognostic significance.

Chronic and Cycling Hypoxia: Drivers of Cancer Chronic Inflammation through HIF-1 and NF-κB Activation: A Review of the Molecular Mechanisms

Chronic (continuous, non-interrupted) hypoxia and cycling (intermittent, transient) hypoxia are two types of hypoxia occurring in malignant tumors. They are both associated with the activation of hypoxia-inducible factor-1 (HIF-1) and nuclear factor κB (NF-κB), which induce changes in gene expression. This paper discusses in detail the mechanisms of activation of these two transcription factors in chronic and cycling hypoxia and the crosstalk between both signaling pathways. In particular, it focuses on the importance of reactive oxygen species (ROS), reactive nitrogen species (RNS) together with nitric oxide synthase, acetylation of HIF-1, and the action of MAPK cascades. The paper also discusses the importance of hypoxia in the formation of chronic low-grade inflammation in cancerous tumors. Finally, we discuss the effects of cycling hypoxia on the tumor microenvironment, in particular on the expression of VEGF-A, CCL2/MCP-1, CXCL1/GRO-α, CXCL8/IL-8, and COX-2 together with PGE₂. These factors induce angiogenesis and recruit various cells into the tumor niche, including neutrophils and monocytes which, in the tumor, are transformed into tumor-associated neutrophils (TAN) and tumor-associated macrophages (TAM) that participate in tumorigenesis.

Role of hypoxia in inhibiting dendritic cells by VEGF signaling in tumor microenvironments: mechanism and application

The tumor microenvironment (TME) plays a central role in tumor initiation, development, immune escape, and clinical treatment. Hypoxia, an important characteristic of the TME, mediates vascular endothelial factor (VEGF) signaling through direct or indirect mechanisms. Directly, hypoxia promotes the expression of VEGF through hypoxia-inducible factor (HIF) induction. Indirectly, VEGF inhibits dendritic cell (DC) maturation and function by binding to VEGF receptors (VEGFRs) and co-receptors expressed on cell membranes. Additionally, HIF can bypass VEGF/VEGFR and activate downstream signaling factors to promote tumor development. Currently, DC vaccine, anti-HIF and anti-VEGF therapies are widely used in clinical treatment, but their long-term effects remain limited. Therefore, a further understanding of the effects of hypoxia and VEGF signaling on DCs will help in the development of innovative combination therapies and the identification of new targets.

Analysis of the Internal Hypoxic Environment in Solid Tumor Tissue Using a Folding Paper System

Hypoxia is a nonphysiological oxygen tension which is common in most malignant tumors. Hypoxia stimulates complicated cell signaling networks in cancer cells, e.g., the HIF, PI3K, MAPK, and NFκB pathways. Then, cells release a number of cytokines such as VEGFA to promote the growth of peripheral blood vessels and lead to metastasis. In the current work, understanding of the internal hypoxic environment in solid tumor tissue was attempted by developing a folding paper system. A paper-based solid tumor was constructed by folding a filter paper cultured with cancer cells. The cellular response in each layer could be analyzed by disassembling the folded paper after the culture course. The result showed that an internal hypoxic environment was successfully reproduced in the paper-based solid tumor. The cells in the inner layer expressed high levels of HIF1-α and VEGFA. Hence, proliferation and migration of endothelial cells were shown to be induced by the cells located in the internal hypoxic environment. Moreover, the paper-based solid tumor was transplanted into nude mice for the study of hypoxic response and angiogenesis. The crosstalk between internal and external parts of solid tumor tissue could be analyzed by sectioning each layer of the paper-based solid tumor. This approach provides a favorable analytical method for the discovery of the interaction between cancer cells, hypoxia, and peripheral angiogenesis.

Sublethal hyperthermia enhances anticancer activity of doxorubicin in chronically hypoxic HepG2 cells through ROS-dependent mechanism

Thermal ablation in combination with transarterial chemoembolization (TACE) has been reported to exert a more powerful antitumor effect than thermal ablation alone in hepatocellular carcinoma patients. However, the underlying mechanisms remain unclear. The purpose of the present study was to evaluate whether sublethal hyperthermia encountered in the periablation zone during thermal ablation enhances the anticancer activity of doxorubicin in chronically hypoxic (encountered in the tumor area after TACE) liver cancer cells and to explore the underlying mechanisms. In the present study, HepG2 cells precultured under chronic hypoxic conditions (1% oxygen) were treated in a 42°C water bath for 15 or 30 min, followed by incubation with doxorubicin. Assays were then performed to determine intracellular uptake of doxorubicin, cell viability, apoptosis, cell cycle, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and total antioxidant capacity. The results confirmed that sublethal hyperthermia enhanced the intracellular uptake of doxorubicin into hypoxic HepG2 cells. Hyperthermia combined with doxorubicin led to a greater inhibition of cell viability and increased apoptosis in hypoxic HepG2 cells as compared with hyperthermia or doxorubicin alone. In addition, the combination induced apoptosis by increasing ROS and causing disruption of MMP. Pretreatment with the ROS scavenger N-acetyl cysteine significantly inhibited the apoptotic response, suggesting that cell death is ROS-dependent. These findings suggested that sublethal hyperthermia enhances the anticancer activity of doxorubicin in hypoxic HepG2 cells via a ROS-dependent mechanism.

Andrographolide Against Lung Cancer-New Pharmacological Insights Based on High-Throughput Metabolomics Analysis Combined with Network Pharmacology

Andrographolide (Andro) has known to treat various illnesses such as colds, diarrhea, fever and infectious diseases. However, the effect mechanism of Andro is still unclear. Therefore, we used high-throughput metabolomics analysis to discover biomarkers, metabolic profiles and pathways to reveal the pharmacological action and effective mechanism of Andro against lung cancer. The metabolic effects of Andro on lung cancer animal was explored by ultra-performance liquid chromatography-triple-time of flight/mass spectrometry (UPLC-TOF/MS) analysis. Our results showed that Andro exhibited significant protective effects against lung cancer. Compared with control group, a total of 25 metabolites biomarkers was identified in urine of model animals, which 18 of them were regulated toward the normal direction after Andro treatment, and network pharmacology analysis showed that they were related with 570 proteins. Biological pathways analysis showed that the 11 metabolism pathways were regulated by Andro treatment in lung cancer mouse, and amino acid metabolism and arachidonic acid metabolism have great potential as target pathways for Andro against lung cancer. It revealed that high-throughput metabolomics combined with network pharmacology analysis provides deeply insight into the therapeutic mechanisms of natural product for promoting medicine development and disease treatment.

Antiangiogenic and Proapoptotic Activities of Atorvastatin and Ganoderma lucidum in Tumor Mouse Model via VEGF and Caspase-3 Pathways

BACKGROUND

The statin drug Atorvastatin (AT) used for cholesterol reduction and Ganoderma lucidum (Gl) mushroom extract exhibited satisfactory antitumor activities towards various types of cancer.

OBJECTIVE

The present study was designed to evaluate the apoptotic and antiangiogenic effects of Atorvastatin and/or Ganoderma lucidum against Ehrlich solid tumor inoculated in female mice.

MATERIALS AND METHODS

Atorvastatin (AT) or/and Ganoderma lucidum (Gl) extract were administered to mice bearing tumor alternatively for 28 days after 10 days of tumor cells inoculation. Mice were divided into 5 equal groups as follows: Control (C): Normal mice, Ehrlich (E): mice injected in thigh with EAC cells, (E+AT): mice bearing solid tumor that received an intraperitoneal dose of Atorvastatin (10 mg/kg). Group (4): (E+Gl): mice bearing solid tumor that received an oral dose of Ganoderma lucidum (28 mg/kg) Group (5):  (E+AT+Gl): mice bearing solid tumor that received intraperitoneal dose of Atorvastatin and oral dose of Ganoderma lucidum.

RESULTS

showed that administration of Atorvastatin and/or Ganoderma lucidum to mice bearing tumor, reduced tumor size, increased MDA level and decreased GSH, SOD and CAT levels in tumor tissues. Histopathological study showed high attenuation in tumor cells associated with antiangiogenesis illustrated by extravasation of blood vessels between tumor cells. Immunohistochemical study demonstrated high reduction of the angiogenic marker Vascular endothelial growth factor (VEGF) with remarkable increase of the apoptotic protein markers cytochrome-c and caspase-3.  Conclusion: Atorvastatin and Ganoderma lucidum may have anticancer, apoptotic and antiangiogenic activities by reducing tumor growth in Ehrlich solid tumor. Their antitumor effect is exerted through the antiangiogenesis effect in tumor cells which is confirmed by the decrease of the angiogenic marker (VEGF protein) as well as by inducing significant increase in the apoptotic protein markers cytochrome-c and caspase-3. It is noticeable that the antitumor activity is ameliorated by the combination of the two treatments.

Sulfasalazine synergistically enhances the inhibitory effects of imatinib against hepatocellular carcinoma (HCC) cells by targeting NFκB, BCR/ABL, and PI3K/AKT signaling pathway-related proteins

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related fatalities worldwide. Identification of second-line therapies for patients with progressive HCC is urgently required as the use of sorafenib and/or regorafenib remains unsatisfactory. Imatinib, a small-molecule kinase inhibitor, is used to treat certain types of cancer, and nuclear factor κB (NFκB) is a positive regulator of cancer cell expansion. The combined use of tyrosine kinase and NFκB inhibitors may have potential for treating HCC. The aim of this work was to assess the potential anticarcinogenic effects of imatinib and sulfasalazine alone or in combination on the human HCC cell lines HEPG2 and Huh-7. Both drugs were shown to affect the phosphoinositide 3-kinase/protein kinase B, phosphorylated signal transducer and activator of translation (p-STAT-3), breakpoint cluster region protein/Abelson proto-oncogene and NFκB pathways. At the transcriptional level, imatinib and sulfasalazine were found to synergistically down-regulate c-MET gene expression. When compared with the activities of either medication alone, combined use of imatinib and sulfasalazine enhanced inhibition of HCC cell proliferation and extended induction of apoptosis. In summary, the presented data suggest that sulfasalazine synergistically potentiates the antitumor effects of imatinib.

MicroRNA-126: A new and promising player in lung cancer

Lung cancer is one of the most common malignant tumors associated with cancer death; however, the mechanisms involved in lung tumor development have not been completely elucidated, which impedes the advancement of clinical diagnosis and therapy. MicroRNA-126 (miR-126) is an important member of the microRNA family and is encoded by intron 7 of epidermal growth factor-like domain-containing gene 7. Increasing evidence has demonstrated that miR-126, as a distinct endothelial-enriched miRNA and new tumor suppressor gene, serves a promising role in the occurrence, development and metastasis of various types of cancer, including liver cancer, colorectal cancer, melanoma and lung cancer. In the present review, the current knowledge of the role of miR-126 in lung cancer growth, metastasis, diagnosis and prognosis as well as therapy was summarized, which may provide new insights on the biological roles of miRNAsin lung cancer and facilitate the ultimate development of miRNA-based therapies in clinical patients with non-small cell lung cancer.

Insights into the New Cancer Therapy through Redox Homeostasis and Metabolic Shifts

Modest levels of reactive oxygen species (ROS) are necessary for intracellular signaling, cell division, and enzyme activation. These ROS are later eliminated by the body’s antioxidant defense system. High amounts of ROS cause carcinogenesis by altering the signaling pathways associated with metabolism, proliferation, metastasis, and cell survival. Cancer cells exhibit enhanced ATP production and high ROS levels, which allow them to maintain elevated proliferation through metabolic reprograming. In order to prevent further ROS generation, cancer cells rely on more glycolysis to produce ATP and on the pentose phosphate pathway to provide NADPH. Pro-oxidant therapy can induce more ROS generation beyond the physiologic thresholds in cancer cells. Alternatively, antioxidant therapy can protect normal cells by activating cell survival signaling cascades, such as the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway, in response to radio- and chemotherapeutic drugs. Nrf2 is a key regulator that protects cells from oxidative stress. Under normal conditions, Nrf2 is tightly bound to Keap1 and is ubiquitinated and degraded by the proteasome. However, under oxidative stress, or when treated with Nrf2 activators, Nrf2 is liberated from the Nrf2-Keap1 complex, translocated into the nucleus, and bound to the antioxidant response element in association with other factors. This cascade results in the expression of detoxifying enzymes, including NADH-quinone oxidoreductase 1 (NQO1) and heme oxygenase 1. NQO1 and cytochrome b5 reductase can neutralize ROS in the plasma membrane and induce a high NAD⁺/NADH ratio, which then activates SIRT1 and mitochondrial bioenergetics. NQO1 can also stabilize the tumor suppressor p53. Given their roles in cancer pathogenesis, redox homeostasis and the metabolic shift from glycolysis to oxidative phosphorylation (through activation of Nrf2 and NQO1) seem to be good targets for cancer therapy. Therefore, Nrf2 modulation and NQO1 stimulation could be important therapeutic targets for cancer prevention and treatment.

Blood and Cancer: Cancer Stem Cells as Origin of Hematopoietic Cells in Solid Tumor Microenvironments

The concepts of hematopoiesis and the generation of blood and immune cells from hematopoietic stem cells are some steady concepts in the field of hematology. However, the knowledge of hematopoietic cells arising from solid tumor cancer stem cells is novel. In the solid tumor microenvironment, hematopoietic cells play pivotal roles in tumor growth and progression. Recent studies have reported that solid tumor cancer cells or cancer stem cells could differentiate into hematopoietic cells. Here, we discuss efforts and research that focused on the presence of hematopoietic cells in tumor microenvironments. We also discuss hematopoiesis from solid tumor cancer stem cells and clarify the notion of differentiation of solid tumor cancer stem cells into non-cancer hematopoietic stem cells.

Gastric Cancer Cell-Derived Exosomal microRNA-23a Promotes Angiogenesis by Targeting PTEN

Hypoxia-exposed lung cancer-released exosomal microRNA-23a (miR-23a) has been shown to enhance angiogenesis as well as vascular permeability, contributing to the close correlation between exosomal miR-23a and tumorigenesis. The current study aimed to investigate whether gastric cancer (GC) cell-derived exosomal miR-23a could induce angiogenesis and to elucidate the potential mechanisms associated with the process. Differentially expressed miRNAs in GC were initially screened from the Gene Expression Omnibus database. Target genes were selected following miRNA-mRNA prediction and subsequently verified by dual luciferase reporter assay. RT-qPCR was conducted to detect miR-23a and PTEN expression in GC tissues, cells and exosomes. Human umbilical venous endothelial cells (HUVECs) were co-cultured with GC cell-derived exosomes to assess the angiogenesis mediated by exosomes in vitro. Additionally, PTEN was overexpressed in HUVECs to analyze the mechanism by which miR-23a regulates angiogenesis. miR-23a was highly expressed in GC tissues and cells and GC cell-derived exosomes. Angiogenesis was promoted by the co-culture of HUVECs and GC cells-derived exosomes, as evidenced by the increased expression of VEGF but decreased expression of TSP-1. PTEN was targeted by miR-23a and was lowly expressed in GC tissues. In a co-culture system, miR-23a carried by GC cells-derived exosomes promoted angiogenesis via the repression of PTEN. Collectively, GC cell-derived exosomal miR-23a could promote angiogenesis and provide blood supply for growth of GC cells. This study contributes to advancement of miRNA-targeted therapeutics.

Simvastatin Mitigates Apoptosis and Transforming Growth Factor-Beta Upregulation in Stretch-Induced Endothelial Cells

Portal hypertension is a common clinical symptom of digestive disorders. With an increase in portal pressure, the portal vein will continue to dilate. We aimed to determine whether continuous stretch induced by portal hypertension may impair the function of endothelial cells (ECs) in the portal vein and aggravate the progress of portal hypertension and explore its mechanism. ECs were cultured on an elastic silicone membrane and subjected to continuous uniaxial stretch. Apoptosis and expression of TGF-β in ECs under stretch were measured. We found that sustained stretch induced the apoptosis of ECs in a stretch length-dependent manner. Compared with the control, continuous stretch increased the nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) expression and damaged the mitochondria, resulting in an evident increase in reactive oxygen species (ROS) levels; pretreatment with gp91ds-tat or MitoTEMPO decreased the ROS level in the intracellular levels. N-acetyl-cysteine (NAC) treatment before stretch not only reduced ROS levels but also mitigated the apoptosis of ECs; simvastatin had similar effects through targeting NOX2 and mitochondria. During the stretch, the phosphorylation of p38 mitogen-activated protein kinase (P38MAPK), c-Jun N-terminal kinase (JNK), and nuclear factor-kappa B (NF-κB) was obviously increased; pretreatment with P38MAPK or JNK inhibitors decreased the phosphorylation of NF-κB and TGF-β expression. Pyrrolidine dithiocarbamate (PDTC) treatment before stretch also reduced TGF-β expression. After pretreatment with NAC, the phosphorylation of P38MAPK, JNK, and NF-κB and TGF-β expressions in ECs under stretch was suppressed; similar results were observed in simvastatin-treated ECs. This study demonstrated that simvastatin could mitigate EC apoptosis and TGF-β upregulation induced by continuous stretch by reducing the level of ROS.

Acute vs. Chronic vs. Cyclic Hypoxia: Their Differential Dynamics, Molecular Mechanisms, and Effects on Tumor Progression

Hypoxia has been shown to increase the aggressiveness and severity of tumor progression. Along with chronic and acute hypoxic regions, solid tumors contain regions of cycling hypoxia (also called intermittent hypoxia or IH). Cyclic hypoxia is mimicked in vitro and in vivo by periodic exposure to cycles of hypoxia and reoxygenation (H-R cycles). Compared to chronic hypoxia, cyclic hypoxia has been shown to augment various hallmarks of cancer to a greater extent: angiogenesis, immune evasion, metastasis, survival etc. Cycling hypoxia has also been shown to be the major contributing factor in increasing the risk of cancer in obstructive sleep apnea (OSA) patients. Here, we first compare and contrast the effects of acute, chronic and intermittent hypoxia in terms of molecular pathways activated and the cellular processes affected. We highlight the underlying complexity of these differential effects and emphasize the need to investigate various combinations of factors impacting cellular adaptation to hypoxia: total duration of hypoxia, concentration of oxygen (O2), and the presence of and frequency of H-R cycles. Finally, we summarize the effects of cycling hypoxia on various hallmarks of cancer highlighting their dependence on the abovementioned factors. We conclude with a call for an integrative and rigorous analysis of the effects of varying extents and durations of hypoxia on cells, including tools such as mechanism-based mathematical modelling and microfluidic setups.