Activation of Epidermal Growth Factor Receptor/p38/Hypoxia-inducible Factor-1α Is Pivotal for Angiogenesis and Tumorigenesis of Malignantly Transformed Cells Induced by Hexavalent Chromium

STUDY OF THE INFLUENCE OF LINDANE AND SODIUM BICHROMATE ON THE MYOCARDIUM

OBJECTIVE

Aim: The aim of the research is to study the immunohistochemical markers of the endothelium of blood vessels and myocardial ventricles under chronic exposure to sodium bichromate and lindane, as well as in conjunction with damaging biochemical agents contained in the blood.

PATIENTS AND METHODS

Materials and Methods: The object of the experiment was outbred white mice (males). The study was carried out in 3 groups: 1st group - control, 2nd group - exposure to sodium bichromate 5 mg/kg, 3rd group - exposure to organochlorine pesticide lindane 100 mg/kg. In this experiment authors used the next methods: immunohistochemical method., biochemical research, statistical analysis.

RESULTS

Results: The data obtained from an experimental study show that the level of cardiomarkers in blood plasma is characterized by different changes when exposed to these two compounds. Basically, the predominance of the effect of sodium bichromate on the LDH level is noted as compared to the effect of lindane; on the CK-MB level, their effects were the same, i.e., there is an increase in their level in blood plasma.

CONCLUSION

Conclusions: Thus, long-term exposure to sodium bichromate leads to the activation of angiogenesis, destruction of the integrity of the endothelium, and this, in turn, leads to reparative changes located around in the myocardial cells.

Process enhancing strategies for the reduction of Cr(VI) to Cr(III) via photocatalytic pathway

This discourse aimed at providing insight into the strategies that can be adopted to boost the process of photoreduction of Cr(VI) to Cr(III). Cr(VI) is amongst the highly detestable pollutants; thus, its removal or reduction to an innocuous and more tolerable Cr(III) has been the focus. The high promise of photocatalysis hinged on the sustainability, low cost, simplicity, and zero sludge generation. Consequently, the present dissertation provided a comprehensive review of the process enhancement procedures that have been reported for the photoreduction of Cr(VI) to Cr(III). Premised on the findings from experimental studies on Cr(VI) reductions, the factors that enhanced the process were identified, dilated, and interrogated. While the salient reaction conditions for the process optimization include the degree of ionization of reacting medium, available photogenerated electrons, reactor ambience, type of semiconductors, surface area of semiconductor, hole scavengers, quantum efficiency, and competing reactions, the relevant process variables are photocatalyst dosage, initial Cr(VI) concentration, interfering ion, and organic load. In addition, the practicability of photoreduction of Cr(VI) to Cr(III) was explored according to the potential for photocatalyst recovery, reactivation, and reuse reaction conditions and the process variables.

A comprehensive analysis on source-distribution-bioaccumulation-exposure risk of metal(loid)s in various vegetables in peri-urban areas of Shenzhen, China

The health risk induced by metal(loid)s in crops are becoming increasingly serious. In this study, eight major vegetables and rhizosphere soils were collected in a peri-urban area with intense electronic information manufacturing activities. The source, distribution and bioaccumulation of six typical metal(loid)s in different vegetable species were analyzed, and exposure risk through vegetable ingestion was estimated. Results showed that vegetables and agricultural soils in the study area suffered from serious metal(loid)s pollution, especially for Cd and Pb. The bioaccumulation capacity differed greatly among individual metal(loid)s and vegetable categories. In general, the highest transfer factors (TF) for Cd, Pb, and As were found in leafy vegetables, while leguminous vegetables had the highest TF of Cu and Zn and root vegetables had the highest TF for Cr. Significant correlations were found between concentrations in vegetables and rhizosphere soils for most metal(loid)s, the exceptions being Pb and Zn. The enrichment of Pb, Cd, Cr and As was mainly attributed to electronic information manufacturing activities, while the enrichment of Zn, Cu and Cd was associated with the application of commercial fertilizers and pesticides. The health risk associated with vegetable intake decreased in the order of leafy > fruit > leguminous > root vegetables. Leafy vegetables were identified as the category with the highest risk, with the mean risk value of 1.26. Cd was the major risk element for leafy vegetables. The non-carcinogenic risks estimated for leguminous and root vegetables were under the acceptable level. In conclusion, special attention should be paid to the health risks of toxic metal(loid)s in leafy vegetables in peri-urban areas with intense electronic information manufacturing activities. In order to minimize health risk, it is necessary to identify low-risk crops based on a comprehensive consideration of the metal(loid)s' pollution characteristics, transfer factors and local people's consumption behaviors.

Nephronectin promotes cardiac repair post myocardial infarction via activating EGFR/JAK2/STAT3 pathway

Background: ECM proteins are instrumental for angiogenesis, which plays momentous roles during development and repair in various organs, including post cardiac insult. After a screening based on an open access RNA-seq database, we identified Nephronectin (NPNT), an extracellular protein, might be involved in cardiac repair post myocardial infarction (MI). However, the specific impact of nephronectin during cardiac repair in MI remains elusive. Methods and Results: In the present study, we established a system overexpressing NPNT locally in mouse heart by utilizing a recombinant adeno-associated virus. One-to-four weeks post MI induction, we observed improved cardiac function, limited infarct size, alleviated cardiac fibrosis, with promoted angiogenesis in infarct border zone in NPNT overexpressed mice. And NPNT treatment enhanced human umbilical vascular endothelial cell (HUVEC) migration and tube formation, putatively through advocating phosphorylation of EGFR/JAK2/STAT3. The migration and capillary-like tube formation events could be readily revoked by EGFR or STAT3 inhibition. Notably, phosphorylation of EGFR, JAK2 and STAT3 were markedly upregulated in AAV2/9-cTnT-NPNT-treated mice with MI. Conclusions: Our study thus identifies the beneficial effects of NPNT on angiogenesis and cardiac repair post MI by enhancing the EGFR/JAK2/STAT3 signaling pathway, implying the potential therapeutic application of NPNT on myocardial dysfunction post MI.

Issues of origin, morphology and clinical significance of tumor microvessels in gastric cancer

Gastric cancer (GC) remains a serious oncological problem, ranking third in the structure of mortality from malignant neoplasms. Improving treatment outcomes for this pathology largely depends on understanding the pathogenesis and biological characteristics of GC, including the identification and characterization of diagnostic, prognostic, predictive, and therapeutic biomarkers. It is known that the main cause of death from malignant neoplasms and GC, in particular, is tumor metastasis. Given that angiogenesis is a critical process for tumor growth and metastasis, it is now considered an important marker of disease prognosis and sensitivity to anticancer therapy. In the presented review, modern concepts of the mechanisms of tumor vessel formation and the peculiarities of their morphology are considered; data on numerous factors influencing the formation of tumor microvessels and their role in GC progression are summarized; and various approaches to the classification of tumor vessels, as well as the methods for assessing angiogenesis activity in a tumor, are highlighted. Here, results from studies on the prognostic and predictive significance of tumor microvessels in GC are also discussed, and a new classification of tumor microvessels in GC, based on their morphology and clinical significance, is proposed for consideration.

Constitutive Activation of NAD-Dependent Sirtuin 3 Plays an Important Role in Tumorigenesis of Chromium(VI)-Transformed Cells

Chronic exposure of human bronchial epithelial BEAS-2B cells to hexavalent chromium [Cr(VI)] causes malignant cell transformation. Sirtuin-3 (SIRT3) regulates mitochondrial adaptive response to stress, such as metabolic reprogramming and antioxidant defense mechanisms. In Cr(VI)-transformed cells, SIRT3 was upregulated and mitochondrial adenosine triphosphate (ATP) production and proton leak were reduced. Knockdown of SIRT3 by its shRNA further decreased mitochondrial ATP production, proton leak, mitochondrial mass, and mitochondrial membrane potential, indicating that SIRT3 positively regulates mitochondrial oxidative phosphorylation and maintenance of mitochondrial integrity. Mitophagy is critical to maintain proper cellular functions. In Cr(VI)-transformed cells expressions of Pink 1 and Parkin, two mitophagy proteins, were elevated, and mitophagy remained similar as that in passage-matched normal BEAS-2B cells, indicating that in -Cr(VI)-transformed cells mitophagy is suppressed. Knockdown of SIRT3 induced mitophagy, suggesting that SIRT3 plays an important role in mitophagy suppression of Cr(VI)-transformed cells. In Cr(VI)-transformed cells, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was constitutively activated, and protein levels of p62 and p-p62Ser349 were elevated. Knockdown of SIRT3 or treatment with carbonyl cyanide m-chlorophenyl hydrazone (CCCP) decreased the binding of p-p62Ser349 to Keap1, resulting in increased binding of Keap1 to Nrf2 and consequently reduced Nrf2 activation. The results from CHIP assay showed that in Cr(VI)-transformed cells binding of Nrf2 to antioxidant response element (ARE) of SIRT3 gene promoter was dramatically increased. Knockdown of SIRT3 suppressed cell proliferation and tumorigenesis of Cr(VI)-transformed cells. Overexpression of SIRT3 in normal BEAS-2B cells exhibited mitophagy suppression phenotype and increased cell proliferation and tumorigenesis. The present study demonstrated that upregulation of SIRT3 causes mitophagy suppression and plays an important role in cell survival and tumorigenesis of Cr(VI)-transformed cells.

Human CCR6+ Th17 Lymphocytes Are Highly Sensitive to Radiation-Induced Senescence and Are a Potential Target for Prevention of Radiation-Induced Toxicity

PURPOSE

This study addresses the sensitivity of different peripheral CD4⁺ T-lymphocyte subsets to irradiation (IR) and identifies potential targets for the prevention or treatment of radiation-induced toxicity.

METHODS

This study was performed on peripheral blood mononuclear cells or sorted peripheral memory lymphocytes of CCR6⁺ mucosa-homing Th17/CCR6^negTh and regulatory T subtypes of healthy volunteers. Cells were irradiated with a 2 Gy with or without pharmacologic inhibitors of different signaling pathways. Senescence of irradiated cells was assessed by resistance to apoptosis and determination of various senescence-associated biomarkers (senescence associated b-galactosidase activity, p16Ink4a-, p21Cdkn1a-, gH2A.X-, H2A.J expression). Cytokine production was measured in supernatants of irradiated cells by Luminex technology.

RESULTS

Not all CD4⁺ memory T lymphocyte subsets were equally radiosensitive. High sensitivity of CCR6⁺Th17 lymphocytes to IR-induced senescence was shown by expression of the histone variant H2A.J, higher SA-b-Gal activity, and upregulation of p16^Ink4a and p21^Cdkn1a expression. Lower Annexin V staining and cleaved caspase-3, and higher expression of antiapoptotic genes Bcl-2 and Bcl-xL LF, showed that CCR6⁺Th17 lymphocytes were more resistant to IR-induced apoptosis than CCR6^neg memory Th and regulatory T lymphocytes. After a 2 Gy IR, both CCR6⁺Th17 and CCR6^neg cells acquired a moderate senescence-associated secretory phenotype, but only CCR6⁺Th17 cells secreted interleukin 8 (IL-8) and vascular endothelial growth factor-A (VEGF-A). Pharmacologic targeting of reactive oxygen species (ROS), mitogen-activated protein kinases (MAPKs), and mammalian target of rapamycin (mTOR) signaling pathways prevented the expression of senescent markers and IL-8 and VEGF-A expression by CCR6⁺Th17 cells after IR.

CONCLUSIONS

This study suggests that IR induces senescence of CCR6+Th17 lymphocytes associated with secretion of IL-8 and VEGF-A that may be detrimental to the irradiated tissue. ROS-MAPKs signaling pathways are candidate targets to prevent this CCR6⁺Th17-dependent radiation-induced potential toxicity. Finally, the ratio of circulating H2A.J⁺ senescent CCR6⁺ Th17/CD4⁺ T lymphocytes may be a candidate marker of individual intrinsic radiosensitivity.

ALDH2 (Aldehyde Dehydrogenase 2) Protects Against Hypoxia-Induced Pulmonary Hypertension

OBJECTIVE

Hypoxia-induced pulmonary hypertension (HPH) increases lipid peroxidation with generation of toxic aldehydes that are metabolized by detoxifying enzymes, including ALDH2 (aldehyde dehydrogenase 2). However, the role of lipid peroxidation and ALDH2 in HPH pathogenesis remain undefined. Approach and Results: To determine the role of lipid peroxidation and ALDH2 in HPH, C57BL/6 mice, ALDH2 transgenic mice, and ALDH2 knockout (ALDH2^-/-) mice were exposed to chronic hypoxia, and recombinant tissue-specific ALDH2 overexpression adeno-associated viruses were introduced into pulmonary arteries via tail vein injection for ALDH2 overexpression. Human pulmonary artery smooth muscle cells were used to elucidate underlying mechanisms in vitro. Chronic hypoxia promoted lipid peroxidation due to the excessive production of reactive oxygen species and increased expression of lipoxygenases in lung tissues. 4-hydroxynonenal but not malondialdehyde level was increased in hypoxic lung tissues which might reflect differences in detoxifying enzymes. ALDH2 overexpression attenuated the development of HPH, whereas ALDH2 knockout aggravated it. Specific overexpression of ALDH2 using AAV1 (adeno-associated virus)-ICAM (intercellular adhesion molecule) 2p-ALDH2 and AAV2-SM22αp (smooth muscle 22 alpha)-ALDH2 viral vectors in pulmonary artery smooth muscle cells, but not endothelial cells, prevented the development of HPH. Hypoxia or 4-hydroxynonenal increased stabilization of HIF (hypoxia-inducible factor)-1α, phosphorylation of Drp1 (dynamin-related protein 1) at serine 616, mitochondrial fission, and pulmonary artery smooth muscle cells proliferation, whereas ALDH2 activation suppressed the latter 3.

CONCLUSIONS

Increased 4-hydroxynonenal level plays a critical role in the development of HPH. ALDH2 attenuates the development of HPH by regulating mitochondrial fission and smooth muscle cell proliferation suggesting ALDH2 as a potential new therapeutic target for pulmonary hypertension.

Mitochondrial Toxicity of Azithromycin Results in Aerobic Glycolysis and DNA Damage of Human Mammary Epithelia and Fibroblasts

Mitochondria evolved from free-living bacteria via endocytosis within eukaryotic host cells millions of year ago. We hypothesized that antibiotics cause mammalian mitochondrial damage while causing bacterial lethality. Mitochondrial toxicity of azithromycin in human mammary epithelia MCF-12A and fibroblasts were tested by fluorescent and transmission electron microscopy. Gene expression and DNA damage were tested by real-time polymerase chain reaction (qPCR) and ELISA. We found azithromycin suppressed the mitochondrial membrane potential gradient of MCF-12A cells and fibroblasts. Ultrastructure exams showed that the antibiotic caused vacuolated and swollen mitochondria with disrupted cristae in MCF-12A cells and fibroblasts compared to the morphology of mitochondria in the cells without antibiotic treatment. Fluorescent microscopy also showed azithromycin-induced mitochondrial reactive oxygen species (ROS), superoxide, after 3 h of culture. The DNA oxidative damage product, 8-hydroxy-2’-deoxyguanosine (8-OHdG, significantly increased in the media after MCF-12A cells and fibroblasts were cultured in the media containing azithromycin for 24 h. Azithromycin upregulated gene expression of hypoxia inducible factor 1 alpha (HIF1a), glycolytic enzymes including hexokinase 2 (HK2), phosphofructokinase 1 (PFKM), pyruvate kinase muscle isozyme M2 (PKM2), and glucose transporters in MCF-12A cells and fibroblasts. Lactate production also increased in the culture media. After treatment with azithromycin, healthy MCF-12A and fibroblast cells increased aerobic glycolysis—the “Warburg Effect”—to generate energy. In summary, azithromycin caused mitochondrial toxicity, ROS overproduction, DNA oxidative damage, upregulation of the HIF1a gene, and aerobic glycolysis in healthy mammalian cells. Over-usage of antibiotics could contribute to tumorigenesis and neurodegeneration and aggravate existing mitochondria-associated diseases.

Molecular and epigenetic mechanisms of Cr(VI)-induced carcinogenesis

Chromium (Cr) is a naturally occurring metallic element found in the Earth's crust. While trivalent chromium ([Cr(III)] is considered non-carcinogenic, hexavalent chromium [Cr(VI)] has long been established as an IARC class I human carcinogen, known to induce cancers of the lung. Current literature suggests that Cr(VI) is capable of inducing carcinogenesis through both genetic and epigenetic mechanisms. Although much has been learned about the molecular etiology of Cr(VI)-induced lung carcinogenesis, more remains to be explored. In particular, the explicit epigenetic alterations induced by Cr(VI) in lung cancer including histone modifications and miRNAs, remain understudied. Through comprehensive review of available literature found between 1973 and 2019, this article provides a summary of updated understanding of the molecular mechanisms of Cr(VI)-carcinogenesis. In addition, this review identifies potential research gaps in the areas of histone modifications and miRNAs, which may prompt new niches for future research.

Suppression of miR-143 contributes to overexpression of IL-6, HIF-1α and NF-κB p65 in Cr(VI)-induced human exposure and tumor growth

Hexavalent chromium [Cr(VI)] is a known occupational and environmental contaminant and carcinogen, but new mechanisms of Cr(VI)-induced carcinogenesis remain to be elucidated. In this study, we found that expression of miR-143 is decreased, whereas that of Interleukin 6 (IL-6) is increased in blood samples of Cr(VI)-exposing workers compared with corresponding unexposed workers. In addition, IL-6 was increased in human bronchial epithelial cells (BEAS-Cr) exposed to Cr(VI) compared with unexposed BEAS-2B cells. To further investigate the mechanisms by which Cr(VI) promotes these changes, we assessed the effects of miR-143 on gene expression and found that miR-143 suppressed expression of IL-6, HIF-1α and NF-κB p65, and that inhibiting miR-143 promoted expression of IL-6, HIF-1α and NF-κB p65. Interestingly, IL-6 regulated expression of HIF-1α, and HIF-1α transcriptionally regulated expression of IL-6. Experiments in animals showed that miR-143 inhibited tumor growth and angiogenesis by regulating IL-6/HIF-1α and downstream signaling pathways in vivo. These outcomes support the hypothesis that the miR-143/IL-6/HIF-1α pathway functions to regulate Cr(VI)-induced carcinogenesis.

Selective activation of tumor-suppressive MAPKP signaling pathway by triptonide effectively inhibits pancreatic cancer cell tumorigenicity and tumor growth

The mitogen-activated protein kinase (MAPK, 1K) family members ERK, JNK, and p38 play a divergent role in either promoting tumorigenesis or tumor-suppression. Activation of ERK and JNK promotes tumorigenesis; whereas, escalation of p38 inhibits carcinogenesis. As these three MAPK members are controlled by the common up-stream MAPK signaling proteins which consist of MAPK kinases (2K) and MAPK kinase kinases (3K), how to selectively actuate tumor-suppressive p38, not concurrently stimulate tumorigenic ERK and JNK, in cancer cells is a challenge for cancer researchers, and a new opportunity for novel anti-cancer drug discovery. Using human pancreatic cancer cells and xenograft mice as models, we found that a small molecule triptonide first discerningly activated the up-stream MAPK kinase kinase MEKK4, not the other two 3K members ASK1 and GADD45; and then selectively actuated the middle stream MAPK kinase MKK4, not the other two 2K members MKK3 and MKK6; and followed by activation of the MAPK member p38, not the other two members ERK and JNK. These data suggest that triptonide is a selective MEKK4-MKK4-p38 axis agonist. Consequently, selective activation of the MEKK4-MKK4-p38 signaling axis by triptonide activated tumor suppressor p21 and inhibited CDK3 expression, resulting in cancer cell cycle arrest at G2/M phase and marked inhibition of pancreatic cancer cell tumorigenic capability in vitro and tumor growth in xenograft mice. Our findings support the notion that selective activation of tumor-suppressive MEKK4-MKK4-p38-p21signaling pathway by triptonide is a new approach for pancreatic cancer therapy, providing a new drug candidate for development of novel anti-cancer therapeutics.

Toxic effects of Cr(VI) on the bovine hemoglobin and human vascular endothelial cells: Molecular interaction and cell damage

Hexavalent chromium [Cr(VI)] is the main harmful component in the atmosphere released by chemical industry. The study was conducted to assess Cr(VI) inducing cardiovascular diseases (CVDs) in vitro by investigating the effects of Cr(VI) on bovine hemoglobin (BHb) and human umbilical vein endothelial cells (HUVECs). Multi-spectroscopic techniques and molecular docking method were used to determine the interaction of Cr(VI) and BHb. Fluorescence spectra results showed that the quenching constant (K_sv) decreased with temperature raise, indicating that Cr(VI) quenches BHb fluorescence through static quenching mechanism. The number of binding sites was 1.14 (310 K), enthalpy and entropy changes revealed the interaction of Cr(VI) and BHb was driven by hydrogen bonds. The results of synchronous fluorescence and circular dichroism (CD) spectra suggested that Cr(VI) could change BHb conformation and influence the microenvironment of Trp and Tyr residues. Moreover, in order to study Cr(VI) induced HUVECs damage, inflammatory factors were detected at the mRNA level, JNK and p38 MAPK pathways were analyzed. The results shown that Cr(VI) could induce mRNA expression of NLRP3, ICAM-1, VCAM-1, TNF-α and IL-1β, and increased intracellular ROS. Furthermore, Cr(VI) could induce oxidative stress in HUVECs, and then activate JNK and p38 MAPK pathways, ultimately lead to apoptosis of HUVECs by activating mitochondrial apoptosis pathways. These results suggested that Cr(VI) might bring about CVDs by both changing the BHb conformation and inducing HUVECs damage.

Investigating the Role of Mitochondrial Respiratory Dysfunction during Hexavalent Chromium-Induced Lung Carcinogenesis

Hexavalent chromium [Cr(VI)] is a lung carcinogen and its complete mechanism of action remains to be investigated. Metabolic reprogramming of key energy metabolism pathways (e.g., increased anaerobic glycolysis in the presence of oxygen or "Warburg effect", dysregulated mitochondrial function, and lipogenesis) are important to cancer cell and tumor survival and growth. In our current understanding of Cr(VI)-induced carcinogenesis, the role for metabolic reprogramming remains unclear. In this study, we treated human lung epithelial cells (BEAS-2B) with Cr(VI) for 6 months and obtained malignantly transformed cells from an isolated colony grown in soft agar. We also used Cr(VI)-transformed cells from two other human lung cell lines (BEP2D and WTHBF-6 cells). Overall, we found that all the Cr(VI)-transformed cells had no changes in their mitochondrial respiratory functions (measured by the Seahorse Analyzer) compared with passaged-matched control cells. Using a xenograft tumor growth model, we generated tumors from these transformed cells in Nude mice. Using cells obtained from the xenograft tumor tissues, we observed that these cells had decreased maximal mitochondrial respiration, spare respiratory capacity, and coupling efficiency. These results provide evidence that, although mitochondrial dysfunction does not occur during Cr(VI)-induced transformation of lung cells, it does occur during tumor development.

Agonist-Biased Signaling via Matrix Metalloproteinase-9 Promotes Extracellular Matrix Remodeling

The extracellular matrix (ECM) is a highly dynamic noncellular structure that is crucial for maintaining tissue architecture and homeostasis. The dynamic nature of the ECM undergoes constant remodeling in response to stressors, tissue needs, and biochemical signals that are mediated primarily by matrix metalloproteinases (MMPs), which work to degrade and build up the ECM. Research on MMP-9 has demonstrated that this proteinase exists on the cell surface of many cell types in complex with G protein-coupled receptors (GPCRs), and receptor tyrosine kinases (RTKs) or Toll-like receptors (TLRs). Through a novel yet ubiquitous signaling platform, MMP-9 is found to play a crucial role not only in the direct remodeling of the ECM but also in the transactivation of associated receptors to mediate and recruit additional remodeling proteins. Here, we summarize the role of MMP-9 as it exists in a tripartite complex on the cell surface and discuss how its association with each of the TrkA receptor, Toll-like receptors, epidermal growth factor receptor, and the insulin receptor contributes to various aspects of ECM remodeling.

Toll-like Receptor 4-Induced Glycolytic Burst in Human Monocyte-Derived Dendritic Cells Results from p38-Dependent Stabilization of HIF-1α and Increased Hexokinase II Expression

Cell metabolism now appears as an essential regulator of immune cells activation. In particular, TLR stimulation triggers metabolic reprogramming of dendritic cells (DCs) with an increased glycolytic flux, whereas inhibition of glycolysis alters their functional activation. The molecular mechanisms involved in the control of glycolysis upon TLR stimulation are poorly understood for human DCs. TLR4 activation of human monocyte-derived DCs (MoDCs) stimulated glycolysis with an increased glucose consumption and lactate production. Global hexokinase (HK) activity, controlling the initial rate-limiting step of glycolysis, was also increased. TLR4-induced glycolytic burst correlated with a differential modulation of HK isoenzymes. LPS strongly enhanced the expression of HK2, whereas HK3 was reduced, HK1 remained unchanged, and HK4 was not expressed. Expression of the other rate-limiting glycolytic enzymes was not significantly increased. Exploring the signaling pathways involved in LPS-induced glycolysis with various specific inhibitors, we observed that only the inhibitors of p38-MAPK (SB203580) and of HIF-1α DNA binding (echinomycin) reduced both the glycolytic activity and production of cytokines triggered by TLR4 stimulation. In addition, LPS-induced HK2 expression required p38-MAPK-dependent HIF-1α accumulation and transcriptional activity. TLR1/2 and TLR2/6 stimulation increased glucose consumption by MoDCs through alternate mechanisms that are independent of p38-MAPK activation. TBK1 contributed to glycolysis regulation when DCs were stimulated via TLR2/6. Therefore, our results indicate that TLR4-dependent upregulation of glycolysis in human MoDCs involves a p38-MAPK-dependent HIF-1α accumulation, leading to an increased HK activity supported by enhanced HK2 expression.

New roles for nuclear EGFR in regulating the stability and translation of mRNAs associated with VEGF signaling

Cell membrane-associated epidermal growth factor receptor (EGFR) translocates into a perinuclear/nuclear location upon stimulation, where it complexes with mRNAs. Treatment with radiation and cisplatin decreases the amounts of mRNAs present within this complex. Gene array analyses of mRNAs in complex with immunoprecipitated nEGFR revealed significant enrichment of different mRNA species compared to the control immunoprecipitation. Functional annotation with help of DAVID Gene Ontology Analysis identified under other terms the HIF-1A/VEGF signaling pathway as one of the top scoring KEGG pathways. RT-PCR and western blots revealed the radiation-induced expression of mRNAs and proteins involved in HIF-1A/VEGF signaling. Simultaneously, the levels of the corresponding validated miRNAs within the complex containing nEGFR and mRNAs were decreased. This finding argues that an mRNA/miRNA/nEGFR complex regulates protein expression. Indeed, we detected the GW182, AGO2, PABPC1 and cNOT1 proteins, which belong to the deadenylase complex, in a complex with nuclear EGFR. Erlotinib-mediated inhibition of EGFR kinase reduced the radiation-induced increase in mRNA expression. In this context, erlotinib reduced AGO2 phosphorylation by the EGFR kinase at residue Y393, which was associated with increased cNOT1 deadenylase activity and reduced mRNA stability. To prove the roles of miRNAs in this context, we transfected cells with an inhibitor of Hsa-mir-1180p5, which targets the NFATC4 mRNA, an mRNA associated with VEGF signaling, or pretreated cells with erlotinib. Indeed, Hsa-mir-1180p5 knockdown increased and the erlotinib treatment decreased the expression of the NFATC4 protein. The expression of the NFATC4 protein controlled the cloning efficiency and radiosensitivity of A549 and FaDu tumor cells. Thus, this study is the first to show that a membrane-located tyrosine kinase receptor, such as EGFR, is internalized to a nuclear/perinuclear location upon exposure to stress and modulates the stability and translation of miRNA-selected mRNAs. This mechanism enables cells to directly express proteins in response to EGFR activation and may contribute to treatment resistance in EGFR-overexpressing tumors.

FAM198B Is Associated with Prolonged Survival and Inhibits Metastasis in Lung Adenocarcinoma via Blockage of ERK-Mediated MMP-1 Expression

Purpose: The comprehensive understanding of mechanisms involved in the tumor metastasis is urgently needed for discovering novel metastasis-related genes for developing effective diagnoses and treatments for lung cancer.Experimental Design: FAM198B was identified from an isogenic lung cancer metastasis cell model by microarray analysis. To investigate the clinical relevance of FAM198B, the FAM198B expression of 95 Taiwan lung adenocarcinoma patients was analyzed by quantitative real-time PCR and correlated to patients' survivals. The impact of FAM198B on cell invasion, metastasis, and tumor growth was examined by in vitro cellular assays and in vivo mouse models. In addition, the N-glycosylation-defective FAM198B mutants generated by site-directed mutagenesis were used to study protein stability and subcellular localization of FAM198B. Finally, the microarray and pathway analyses were used to elucidate the underlying mechanisms of FAM198B-mediated tumor suppression.Results: We found that the high expression of FAM198B was associated with favorable survival in Taiwan lung adenocarcinoma patients and in a lung cancer public database. Enforced expression of FAM198B inhibited cell invasion, migration, mobility, proliferation, and anchorage-independent growth, and FAM198B silencing exhibited opposite activities in vitro FAM198B also attenuated tumor growth and metastasis in vivo We further identified MMP-1 as a critical downstream target of FAM198B. The FAM198B-mediated MMP-1 downregulation was via inhibition of the phosphorylation of ERK. Interestingly deglycosylation nearly eliminated the metastasis suppression activity of FAM198B due to a decrease of protein stability.Conclusions: Our results implicate FAM198B as a potential tumor suppressor and to be a prognostic marker in lung adenocarcinoma. Clin Cancer Res; 24(4); 916-26. ©2017 AACR.

Oxidative Stress and Metabolic Reprogramming in Cr(VI) Carcinogenesis

Cr(VI)-containing compounds are well-established lung carcinogens. Chronic exposure of the normal human epithelial cells is able to induce malignant cell transformation, the first stage of metal carcinogenesis. These Cr(VI)-transformed cells exhibit increased level of antioxidants, reduced capacity of generating reactive oxygen species (ROS), and development of apoptosis resistance, promoting tumorigenesis of Cr(VI)-transformed cells, the second stage of metal carcinogenesis. The mechanism of Cr(VI) induced carcinogenesis is still under investigation. Recent studies indicate that ROS play a positive role in the first stage while a negative role in the second stage. Transformed cells adapt metabolism to support tumor initiation and progression. Altered metabolic activities directly participate in the process of cell transformation or support a large requirement for nucleotides, amino acids, and lipids for tumor growth. In malignantly Cr(VI)-transformed cells, mitochondrial oxidative phosphorylation is defective, and pentose phosphate pathway, glycolysis, and glutaminolysis are upregulated. These metabolic reprogramming supports rapid cell proliferation and contributes to tumorigenesis of Cr(VI)-transformed cells. This article summarizes the current progress in the studies of metabolic reprogramming and Cr(VI) carcinogenesis with emphasis on the metabolic enzymes and oxidative stress related major oncogenic pathways.

ADAM9 promotes lung cancer progression through vascular remodeling by VEGFA, ANGPT2, and PLAT

Lung cancer has a very high prevalence of brain metastasis, which results in a poor clinical outcome. Up-regulation of a disintegrin and metalloproteinase 9 (ADAM9) in lung cancer cells is correlated with metastasis to the brain. However, the molecular mechanism underlying this correlation remains to be elucidated. Since angiogenesis is an essential step for brain metastasis, microarray experiments were used to explore ADAM9-regulated genes that function in vascular remodeling. The results showed that the expression levels of vascular endothelial growth factor A (VEGFA), angiopoietin-2 (ANGPT2), and tissue plasminogen activator (PLAT) were suppressed in ADAM9-silenced cells, which in turn leads to decreases in angiogenesis, vascular remodeling, and tumor growth in vivo. Furthermore, simultaneous high expression of ADAM9 and VEGFA or of ADAM9 and ANGPT2 was correlated with poor prognosis in a clinical dataset. These findings suggest that ADAM9 promotes tumorigenesis through vascular remodeling, particularly by increasing the function of VEGFA, ANGPT2, and PLAT.

Tetrahydrocurcumin induces mesenchymal-epithelial transition and suppresses angiogenesis by targeting HIF-1α and autophagy in human osteosarcoma

Human osteosarcoma is considered a malignant tumor with poor prognosis that readily metastasizes. Tetrahydrocurcumin (THC) has been reported to have anti-tumor activity in numerous tumors. In addition, hypoxia-inducible factor-1α (HIF-1α) has been demonstrated to be associated with tumor metastasis by regulating epithelial-mesenchymal transition (EMT). However, the role of THC in osteosarcoma remains uncertain. Therefore, this study aimed to elucidate the potential mechanisms. We found that THC significantly reduced the growth of osteosarcoma cells and suppressed migration and invasion, as tested in a nude mouse lung metastasis model. Additionally, the mesenchymal-epithelial transition (MET) process was facilitated by THC. Mechanistically, our study showed that HIF-1α had a pivotal role in the anti-metastatic effect of THC. Importantly, HIF-1α expression was downregulated by THC by inhibiting Akt/mTOR and p38 MAPK pathways. Moreover, THC exhibited a remarkable inhibitory effect on HIF-1α expression and angiogenesis under hypoxic conditions. Furthermore, THC activated autophagy and induced MET and suppressed angiogenesis in a HIF-1α-related manner. Taken together, our findings suggest that THC suppresses metastasis and invasion and this may be associated with HIF-1α and autophagy, which would potentially provide therapeutic strategies for human osteosarcoma.

Long noncoding RNAs: emerging regulators of tumor angiogenesis

Long noncoding RNAs (lncRNAs) participate in multiple biological processes especially human diseases, of which, tumor seems to be one of the most significant. Angiogenesis has been deemed to have a pivotal role in a series of tumor biological behaviors in tumorigenesis, progression and prognosis. Emerging evidences suggested that lncRNAs are involved in tumor angiogenesis and lncRNAs have already been verified to be potential biomarkers and promising therapeutic targets. This review summarized emerging angiogenesis-related lncRNAs, discussed their mechanisms interacting with cytokines, cancer stem cells, miRNAs and tumor hypoxia microenvironment, and demonstrated if lncRNAs could be new candidate targets of antiangiogenesis therapy.

Venous component in scar penetrating neovascularisation

BACKGROUND

The impact of old scar tissue on the venous anatomy of a flap's pedicle is an important question in reconstructive surgery. This study tried to investigate the venous component in scar penetrating neovascularisation.

METHODS

Fifty Sprague-Dawley rats were used in this experimental study. Two experimental groups were designed. In the first group, incisions were performed over the epigastric flap pedicles. In the second group, 1 cm wide segments were excised over the pedicles. Ten weeks after the initial operations, angiographies and histological examinations were performed. A control group was used to demonstrate the normal arterial and venous anatomy of the pedicle.

RESULTS

Arterial angiographies revealed that axial pattern arteries were visible in the incision group as opposed to the excision group. Although venous angiographies showed that there were more venous capillary formations in the incision group, none of the experimental groups had regenerated a vein with an axial pattern. Histological examinations revealed that venous vessel formations were significantly less in the distal samples of the experimental groups when compared to the control group (p < 0.05).

CONCLUSIONS

In this study, it has been observed that arterial pedicles do regenerate over old incision scars as opposed to veins. In the excision scars neither arterial or venous restoration of the axial pedicle was possible. In these cases, only a random type of limited circulation was restored.

MicroRNAs: Impaired vasculogenesis in metal induced teratogenicity

Certain metals have been known for their toxic effects on embryos and fetal development. The vasculature in early pregnancy is extremely dynamic and plays an important role in organogenesis. Nascent blood vessels in early embryonic life are considered to be a primary and delicate target for many teratogens since the nascent blood islands follow a tightly controlled program to form vascular plexus around and inside the embryo for resourcing optimal ingredients for its development. The state of the distribution of toxic metals, their transport mechanisms and the molecular events by which they notch extra-embryonic and embryonic vasculatures are illustrated. In addition, pharmacological aspects of toxic metal induced teratogenicity have also been portrayed. The work reviewed state of the current knowledge of specific role of microRNAs (miRNAs) that are differentially expressed in response to toxic metals, and how they interfere with the vasculogenesis that manifests into embryonic anomalies.

Chromium contributes to human bronchial epithelial cell carcinogenesis by activating Gli2 and inhibiting autophagy

Occupational and environmental inhalation exposure to hexavalent chromium [Cr(vi)] compounds has been confirmed to cause respiratory system injury and cancer. The molecular mechanisms of chromium carcinogenesis still require further study. We established Cr(vi)-transformed cells (BEAS-2B-Cr) after chronic exposure of immortalized normal human bronchial epithelial BEAS-2B cells to low doses of Cr(vi), which obtained the ability of anchorage-independent growth. BEAS-2B-Cr cells not only exhibited stronger proliferation, migration, invasion and tumorigenesis capabilities but also acquired an altered and distinct Gli2 gene expression pattern compared with untreated parental BEAS-2B cells (P-NC) and the control BEAS-2B cells (NC). Interestingly, we found that activation of Gli2 by Cr(vi) treatment prevented the induction of autophagy. Using a gene silencing approach, we showed that Gli2 plays an important role in the malignant properties of BEAS-2B-Cr cells. Downregulation of Gli2 induced autophagy and inhibited cell proliferation and colony forming abilities, which are both upregulated in BEAS-2B-Cr cells compared to NC cells. In addition, inhibition of autophagy by 3-methyladenine (3-MA) partially suppressed the cytotoxicity induced by GANT61-induced inhibition of Gli2. These results demonstrate that hexavalent chromium Cr(vi) activates Gli2 to promote the proliferation of BEAS-2B-Cr cells by inhibition of autophagy, which contributes to human bronchial epithelial cell carcinogenesis. Gli2 may not only play an important role in lung cancer pathogenesis, but also be a promising early indicator in monitoring exposure to chromium.

Regulatory roles of epigenetic modulators, modifiers and mediators in lung cancer

Lung cancer as the leading cause of cancer-related deaths can be initiated and progressed by the interaction between dynamically genetic and epigenetic elements, although mechanisms mediating lung cancer development and progression remain unclear. Tumor progenitor genes may contribute to lung carcinogenesis and cancer progression, are epigenetically disrupted at the early stages of malignancies even before mutations, and alter cell differentiation throughout tumor evolution. The present review explores potential roles and mechanisms of epigenetic modulators, modifiers and mediators in the development of lung cancer. We also overviewed potential mechanisms by which epigenetic modulators, modifiers and mediators control and regulate 3D nuclear architectures, and discussed translational efforts to epigenetic modifications for treatment of lung cancer. Deep understanding of epigenetic modulators, modifiers and mediators will benefit the discovery and development of new diagnostics and therapies for lung cancer.

Tumor Necrosis Factor-Alpha and the ERK Pathway Drive Chemerin Expression in Response to Hypoxia in Cultured Human Coronary Artery Endothelial Cells

BACKGROUND

Chemerin, a novel adipokine, plays a role in the inflammation status of vascular endothelial cells. Hypoxia causes endothelial-cell proliferation, migration, and angiogenesis. This study was aimed at evaluating the protein and mRNA expression of chemerin after exposure of human coronary artery endothelial cells (HCAECs) to hypoxia.

METHODS AND RESULTS

Cultured HCAECs underwent hypoxia for different time points. Chemerin protein levels increased after 4 h of hypoxia at 2.5% O2, with a peak of expression of tumor necrosis factor-alpha (TNF-alpha) at 1 h. Both hypoxia and exogenously added TNF-alpha during normoxia stimulated chemerin expression, whereas an ERK inhibitor (PD98059), ERK small interfering RNA (siRNA), or an anti-TNF-alpha antibody attenuated the chemerin upregulation induced by hypoxia. A gel shift assay indicated that hypoxia induced an increase in DNA-protein binding between the chemerin promoter and transcription factor SP1. A luciferase assay confirmed an increase in transcriptional activity of SP1 on the chemerin promoter during hypoxia. Hypoxia significantly increased the tube formation and migration of HCAECs, whereas PD98059, the anti-TNF-alpha antibody, and chemerin siRNA each attenuated these effects.

CONCLUSION

Hypoxia activates chemerin expression in cultured HCAECs. Hypoxia-induced chemerin expression is mediated by TNF-alpha and at least in part by the ERK pathway. Chemerin increases early processes of angiogenesis by HCAECs after hypoxic treatment.

Coexpression and expression quantitative trait loci analyses of the angiogenesis gene-gene interaction network in prostate cancer

BACKGROUND

Prostate cancer (PCa) shows a substantial clinical heterogeneity. The existing risk classification for PCa prognosis based on clinical factors is not sufficient. Although some biomarkers for PCa aggressiveness have been identified, their underlying functional mechanisms are still unclear. We previously reported a gene-gene interaction network associated with PCa aggressiveness based on single nucleotide polymorphism (SNP)-SNP interactions in the angiogenesis pathway. The goal of this study is to investigate potential functional evidence of the involvement of the genes in this gene-gene interaction network.

METHODS

A total of 11 angiogenesis genes were evaluated. The crosstalks among genes were examined through coexpression and expression quantitative trait loci (eQTL) analyses. The study population is 352 Caucasian PCa patients in the Cancer Genome Atlas (TCGA) study. The pairwise coexpressions among the genes of interest were evaluated using the Spearman coefficient. The eQTL analyses were tested using the Kruskal-Wallis test.

RESULTS

Among all within gene and 55 possible pairwise gene evaluations, 12 gene pairs and one gene (MMP16) showed strong coexpression or significant eQTL evidence. There are nine gene pairs with a strong correlation (Spearman correlation ≥0.6, P<1×10^-13). The top coexpressed gene pairs are EGFR-SP1 (r=0.73), ITGB3-HSPG2 (r=0.71), ITGB3-CSF1 (r=0.70), MMP16-FBLN5 (r=0.68), ITGB3-MMP16 (r=0.65), ITGB3-ROBO1 (r=0.62), CSF1-HSPG2 (r=0.61), CSF1-FBLN5 (r=0.6), and CSF1-ROBO1 (r=0.60). One cis-eQTL in MMP16 and five trans-eQTLs (MMP16-ESR1, ESR1-ROBO1, CSF1-ROBO1, HSPG2-ROBO1, and FBLN5-CSF1) are significant with a false discovery rate q value less than 0.2.

CONCLUSIONS

These findings provide potential biological evidence for the gene-gene interactions in this angiogenesis network. These identified interactions between the angiogenesis genes not only provide information for PCa etiology mechanism but also may serve as integrated biomarkers for building a risk prediction model for PCa aggressiveness.

Cyclooxygenase-2 is associated with malignant phenotypes in human lung cancer

The objective of the present study was to investigate whether cyclooxygenase-2 (COX-2) is associated with malignancy, and to investigate its molecular mechanisms in human lung cancer tumor malignancy. The present study used RNA interference (RNAi) methodology and celecoxib, a COX-2 inhibitor, to investigate the effect of COX-2 knockdown on the proliferation and invasion abilities of lung cancer cells and the molecular mechanisms involved. Human lung adenocarcinoma A549-si10 and LTEP-A2 cells transfected with a specific small interfering RNA (A549-si10 and LTEP-A2-si10, respectively) grew more slowly compared with parental cell lines and cells transfected with pU6. The colony formation of A549-si10 and LTEP-A2-si10 cells was also reduced. In addition, A549-si10 and LTEP-A2-si10 cells were characterized by decreased metastatic and invasive abilities. The proliferation and invasive potential of parental A549 and LTEP-A2 cells was inhibited following treatment with celecoxib. In vivo, a COX-2 knockdown resulted in a decrease of proliferation and reduction of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and endothelial growth factor receptor (EGFR) expression in A549 xenografts. In conclusion, the present study revealed that COX-2 plays a extremely important role in tumor growth, infiltration and metastasis via the regulation of VEGF, MMP-2 and EGRF expression. Therefore, COX-2 is a potential therapeutic target for lung cancer.