Mild exposure to fine particulate matter promotes angiogenesis in non-small cell lung carcinoma.

Fine particulate matter (PM2.5) is associated with public health problems worldwide. Especially, PM2.5 induces epigenetic and microenvironmental changes in lung cancer. Angiogenesis is important for the development and growth of cancer and is mediated by angiogenic factors, including vascular endothelial growth factor. However, the effects of mild PM2.5 exposure on angiogenesis in lung cancer remain unclear. In this study, we examined angiogenic effects using relatively lower concentrations of PM2.5 than in other studies and found that PM2.5 increased angiogenic activities in both endothelial cells and non-small cell lung carcinoma cells. PM2.5 also promoted the growth and angiogenesis of lung cancer via the induction of hypoxia-inducible factor-1α (HIF-1α) in a xenograft mouse tumor model. Angiogenic factors, including vascular endothelial growth factor (VEGF), were highly expressed in lung cancer patients in countries with high PM2.5 levels in the atmosphere, and high expression of VEGF in lung cancer patients lowered the survival rate. Collectively, these results provide new insight into the mechanisms by which mild exposure to PM2.5 is involved in HIF-1α-mediated angiogenesis in lung cancer patients.

Angiogenic activities are increased via upregulation of HIF-1α expression in gefitinib-resistant non-small cell lung carcinoma cells.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) have been used to treat patients with non-small cell lung cancer (NSCLC) and activating EGFR mutations; however, the emergence of secondary mutations in EGFR or the acquisition of resistance to EGFR-TKIs can develop and is involved in clinical failure. Since angiogenesis is associated with tumor progression and the blockade of antitumor drugs, inhibition of angiogenesis could be a rational strategy for developing anticancer drugs combined with EGFR-TKIs to treat patients with NSCLC. The signaling pathway mediated by hypoxia-inducible factor-1 (HIF-1) is essential for tumor angiogenesis. The present study aimed to identify the dependence of gefitinib resistance on HIF-1α activity using angiogenesis assays, western blot analysis, colony formation assay, xenograft tumor mouse model and immunohistochemical analysis of tumor tissues. In the NSCLC cell lines, HIF-1α protein expression levels and hypoxia-induced angiogenic activities were found to be increased. In a xenograft mouse tumor model, tumor tissues derived from gefitinib-resistant PC9 cells showed increased protein expression of HIF-1α and angiogenesis within the tumors. Furthermore, inhibition of HIF-1α suppressed resistance to gefitinib, whereas overexpression of HIF-1α increased resistance to gefitinib. The results from the present study provides evidence that HIF-1α was associated with the acquisition of resistance to gefitinib and suggested that inhibiting HIF-1α alleviated gefitinib resistance in NSCLC cell lines.

ß-arrestin 2 stimulates degradation of HIF-1α and modulates tumor progression of glioblastoma.

The basic function of ß-arrestin 2 (Arrb2) is to negatively regulate the G-protein-coupled receptor signaling pathway through facilitating receptor desensitization and internalization. Arrb2 has also been reported to play various roles in cancer pathology including the proliferation, migration, invasion, metastasis, and apoptosis of solid tumors. However, the molecular mechanisms underlying the tumorigenic capacities of Arrb2 have not been elucidated. Here, we show a novel function of Arrb2: Arrb2 facilitates the degradation of HIF-1α, which is a master regulator of oxygen homeostasis. We also demonstrate that Arrb2 interacts with HIF-1α and stimulates ubiquitin-mediated 26S proteasomal degradation of HIF-1α by recruiting PHD2 and pVHL. Overexpression of Arrb2 in human glioblastoma cells suppresses HIF-1α signaling, tumor growth, and angiogenesis. Consistent with this antitumorigenic effect of Arrb2, low Arrb2 expression levels correlate with high HIF-1α expression and poor glioblastoma patient survival. These results collectively reveal a novel function of Arrb2 in the oxygen-sensing mechanism that directly regulates HIF-1α stability in human cancers and suggest Arrb2 as a new potential therapeutic target for glioblastoma.

Ischemia induces autophagy of endothelial cells and stimulates angiogenic effects in a hindlimb ischemia mouse model.

Although peripheral artery disease (PAD) is a major health problem, there have been limited advances in medical therapies. In PAD patients, angiogenesis is regarded as a promising therapeutic strategy to promote new arterial vessels and improve perfusion of ischemic tissue. Autophagy plays a critical role in catabolic processes for cell survival under normal and stressful conditions and plays fundamental biological roles in various cellular functions. In the present study, we showed that autophagy in endothelial cells is important for the repair and regeneration of damaged tissues. In a hindlimb ischemia mouse model, autophagy was stimulated in endothelial cells of the quadriceps muscle, and adjacent cells proliferated and regenerated. The autophagy pathway was induced under prolonged hypoxia in endothelial cells, and autophagy increased angiogenic activities. Moreover, conditioned media from endothelial cells blocked autophagy and inhibited the proliferation of muscle cells, suggesting that autophagic stimulation in endothelial cells affects the survival of adjacent cells, such as muscle. Collectively, hypoxia/ischemia-induced autophagy angiogenesis, and the damaged tissue surrounded by neo-vessels was regenerated in an ischemia model. Therefore, we strongly suggest that stimulation of autophagy in endothelial cells may be a potent therapeutic strategy in severe vascular diseases, including PAD.

Zingerone Suppresses Tumor Development through Decreasing Cyclin D1 Expression and Inducing Mitotic Arrest.

Cancer cells undergo uncontrolled proliferation resulting from aberrant activity of various cell-cycle proteins. Therefore, despite recent advances in intensive chemotherapy, it is difficult to cure cancer completely. Recently, cell-cycle regulators became attractive targets in cancer therapy. Zingerone, a phenolic compound isolated from ginger, is a nontoxic and inexpensive compound with varied pharmacological activities. In this study, the therapeutic effect of zingerone as an anti-mitotic agent in human neuroblastoma cells was investigated. Following treatment of BE(2)-M17 cells with zingerone, we performed a 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay and colony-formation assay to evaluate cellular proliferation, in addition to immunofluorescence cytochemistry and flow cytometry to examine the mitotic cells. The association of gene expression with tumor stage and survival was analyzed. Furthermore, to examine the anti-cancer effect of zingerone, we applied a BALB/c mouse-tumor model using a BALB/c-derived adenocarcinoma cell line. In human neuroblastoma cells, zingerone inhibited cellular viability and survival. Moreover, the number of mitotic cells, particularly those in prometaphase, increased in zingerone-treated neuroblastoma cells. Regarding specific molecular mechanisms, zingerone decreased cyclin D1 expression and induced the cleavage of caspase-3 and poly (ADP-ribose) polymerase 1 (PARP-1). The decrease in cyclin D1 and increase in histone H3 phosphorylated (p)-Ser10 were confirmed by immunohistochemistry in tumor tissues administered with zingerone. These results suggest that zingerone induces mitotic arrest followed by inhibition of growth of neuroblastoma cells. Collectively, zingerone may be a potential therapeutic drug for human cancers, including neuroblastoma.

New Targets for Parkinson's Disease: Adhesion G Protein-Coupled Receptor B1 is Downregulated by AMP-Activated Protein Kinase Activation.

While progressive dopaminergic neurodegeneration is responsible for the cardinal motor defects in Parkinson's disease (PD), new diagnostics and therapeutic targets are necessary to effectively address this major global health burden. We evaluated whether the adhesion G protein-coupled receptor B1 (ADGRB1, formerly BAI1, brain-specific angiogenesis inhibitor 1) might contribute to dopaminergic neuronal loss. We used bioinformatic analyses, as well as in vitro and in vivo PD models. We report in this study that ADGRB1 is decreased in PD and that the ADGRB1 level is specifically decreased in dopaminergic neurons in the substantia nigra of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. In primary mouse mesencephalic neurons and human neuroblastoma cell lines, 1-methyl-4-phenylpyridinium (MPP+), a toxic metabolite of MPTP, suppressed the expression of ADGRB1. Moreover, we applied a network generation tool, Ingenuity Pathway Analysis®, with the transcriptomics dataset to extend the upstream regulatory pathway of ADGRB1 expression. AMP-activated protein kinase (AMPK) was predicted as a regulator, and consequently, 5-aminoimidazole-4-carboxamide ribonucleotide, a specific activator of AMPK, reduced the ADGRB1 protein level. Finally, ADGRB1 overexpression decreased nuclear condensation induced by MPP+ treatment. Taken together, we observed that decreased ADGRB1 by activation of AMPK induced neuronal cell death in MPTP/MPP+-mediated PD models, suggesting that ADGRB1 might potentially play a survival role in the neurodegenerative pathway of PD. These data offer new insights into dopaminergic cell death with therapeutic implications for neurodegenerative disorders.

The Neuroprotective Effects of Cinnamic Aldehyde in an MPTP Mouse Model of Parkinson's Disease.

Cinnamic aldehyde (CA), a key flavor compound in cinnamon essential oil, has been identified as an anti-oxidant, anti-angiogenic, and anti-inflammatory material. Recently, the neuroprotective effects of CA have been reported in various neurodegenerative disorders, including Parkinson's disease (PD). In neurons, autophagy is tightly regulated, and consequently, the dysregulation of autophagy may induce neurodegenerative disorders. In the present study, we found that the selective dopaminergic neuronal death in the substantia nigra of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse models was prevented by CA. Stimulation of microtubule-associated protein light chain 3 (LC3) puncta mediated by MPTP treatment was decreased by CA. Moreover, down-regulated p62 in the substantia nigra of MPTP mice was increased by administration of CA. Finally, we showed that blockage of autophagy using autophagy inhibitors protected the 1-methyl-4-phenylpyridinium (MPP⁺)-mediated death of BE(2)-M17 cells. Together these results suggest that CA has a neuroprotective effect in a PD model and that inhibition of autophagy might be a promising therapeutic target for PD.

Evaluation of non-thermal plasma-induced anticancer effects on human colon cancer cells.

Non-thermal atmospheric-pressure plasma has been introduced in various applications such as sterilization, wound healing, blood coagulation, and other biomedical applications. The most attractive application of non-thermal atmospheric-pressure plasma is in cancer treatment, where the plasma is used to produce reactive oxygen species (ROS) to facilitate cell apoptosis. We investigate the effects of different durations of exposure to dielectric-barrier discharge (DBD) plasma on colon cancer cells using measurement of cell viability and ROS levels, western blot, immunocytochemistry, and Raman spectroscopy. Our results suggest that different kinds of plasma-treated cells can be differentiated from control cells using the Raman data.

Zingerone suppresses angiogenesis via inhibition of matrix metalloproteinases during tumor development.

Angiogenesis is an essential step for tumor survival and progression, and the inhibition of angiogenesis is a good strategy for tumor therapeutics. In this study, we investigated the therapeutic effect of zingerone in a mouse tumor model. Zingerone suppressed tumor progression and tumor angiogenesis. Moreover, we found that zingerone inhibited the angiogenic activities of endothelial cells by both direct and indirect means. A mechanistic study showed that the activities of MMP-2 and MMP-9 in tumor cells were decreased by treatment with zingerone. Interestingly, zingerone-mediated inhibition of MMP-2 and MMP-9 was involved in the JNK pathway. In conclusion, zingerone showed strong anti-angiogenic activity via the inhibition of MMP-2 and MMP-9 during tumor progression, suggesting that zingerone may be a potential therapeutic drug for human cancers.

Zingerone activates VMAT2 during MPP(+) -induced Cell Death.

Parkinson's disease (PD) is characterized by a progressive and selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and striatum. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is used to produce an animal model for PD, and it is converted to 1-methyl-4-phenylpyridine (MPP(+)) in animals. MPP(+) accumulation leads to neuronal cell death. Vesicular monoamine transporter 2 (VMAT2) regulates the accumulation of monoamine neurotransmitters into synaptic vesicles and is involved in neuroprotection against neurotoxin-induced cell death. Recently, zingerone has been reported to reduce oxidative stress and inhibit inflammation. Therefore, we examined the effect of zingerone on neuronal cell death in a PD model. In an MPP(+) and MPTP-mediated PD model, neuronal cell survival was increased by zingerone without modifying neuroinflammation or reactive oxygen species generation. Zingerone also induced ERK activation and VMAT2 expression, leading to the attenuation of MPP(+)-induced neuronal cell death. Our current results suggest that zingerone has a neuroprotective effect in a PD model.

Cinnamic aldehyde suppresses hypoxia-induced angiogenesis via inhibition of hypoxia-inducible factor-1α expression during tumor progression.

During tumor progression, hypoxia-inducible factor 1 (HIF-1) plays a critical role in tumor angiogenesis and tumor growth by regulating the transcription of several genes in response to a hypoxic environment and changes in growth factors. This study was designed to investigate the effects of cinnamic aldehyde (CA) on tumor growth and angiogenesis and the mechanisms underlying CA's anti-angiogenic activities. We found that CA administration inhibits tumor growth and blocks tumor angiogenesis in BALB/c mice. In addition, CA treatment decreased HIF-1α protein expression and vascular endothelial growth factor (VEGF) expression in mouse tumors and Renca cells exposed to hypoxia in vitro. Interestingly, CA treatment did not affect the stability of von Hippel-Lindau protein (pVHL)-associated HIF-1α and CA attenuated the activation of mammalian target of rapamycin (mTOR) pathway. Collectively, these findings strongly indicate that the anti-angiogenic activity of CA is, at least in part, regulated by the mTOR pathway-mediated suppression of HIF-1α protein expression and these findings suggest that CA may be a potential drug for human cancer therapy.