JNK/AP-1 pathway is involved in tumor necrosis factor-alpha induced expression of vascular endothelial growth factor in MCF7 cells

Synergic Role of Dietary Bioactive Compounds in Breast Cancer Chemoprevention and Combination Therapies

Breast cancer is the most common tumor in women. Chemotherapy is the gold standard for cancer treatment; however, severe side effects and tumor resistance are the major obstacles to chemotherapy success. Numerous dietary components and phytochemicals have been found to inhibit the molecular and signaling pathways associated with different stages of breast cancer development. In particular, this review is focused on the antitumor effects of PUFAs, dietary enzymes, and glucosinolates against breast cancer. The major databases were consulted to search in vitro and preclinical studies; only those with solid scientific evidence and reporting protective effects on breast cancer treatment were included. A consistent number of studies highlighted that dietary components and phytochemicals can have remarkable therapeutic effects as single agents or in combination with other anticancer agents, administered at different concentrations and via different routes of administration. These provide a natural strategy for chemoprevention, reduce the risk of breast cancer recurrence, impair cell proliferation and viability, and induce apoptosis. Some of these bioactive compounds of dietary origin, however, show poor solubility and low bioavailability; hence, encapsulation in nanoformulations are promising tools able to increase clinical efficiency.

Surgical Tumor Resection Deregulates Hallmarks of Cancer in Resected Tissue and the Surrounding Microenvironment

Surgery exposes tumor tissue to severe hypoxia and mechanical stress leading to rapid gene expression changes in the tumor and its microenvironment, which remain poorly characterized. We biopsied tumor and adjacent normal tissues from patients with breast (n = 81) and head/neck squamous cancers (HNSC; n = 10) at the beginning (A), during (B), and end of surgery (C). Tumor/normal RNA from 46/81 patients with breast cancer was subjected to mRNA-Seq using Illumina short-read technology, and from nine patients with HNSC to whole-transcriptome microarray with Illumina BeadArray. Pathways and genes involved in 7 of 10 known cancer hallmarks, namely, tumor-promoting inflammation (TNF-A, NFK-B, IL18 pathways), activation of invasion and migration (various extracellular matrix-related pathways, cell migration), sustained proliferative signaling (K-Ras Signaling), evasion of growth suppressors (P53 signaling, regulation of cell death), deregulating cellular energetics (response to lipid, secreted factors, and adipogenesis), inducing angiogenesis (hypoxia signaling, myogenesis), and avoiding immune destruction (CTLA4 and PDL1) were significantly deregulated during surgical resection (time points A vs. B vs. C). These findings were validated using NanoString assays in independent pre/intra/post-operative breast cancer samples from 48 patients. In a comparison of gene expression data from biopsy (analogous to time point A) with surgical resection samples (analogous to time point C) from The Cancer Genome Atlas study, the top deregulated genes were the same as identified in our analysis, in five of the seven studied cancer types. This study suggests that surgical extirpation deregulates the hallmarks of cancer in primary tumors and adjacent normal tissue across different cancers.

IMPLICATIONS

Surgery deregulates hallmarks of cancer in human tissue.

Early growth response 1 regulates dual‑specificity protein phosphatase 1 and inhibits cell migration and invasion of tongue squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors in the head and neck, and among the OSCCs, tongue squamous cell carcinoma (TSCC) is one of the most common types. Although therapy strategies have recently advanced, the prognosis of TSCC has not substantially improved. Metastasis is one of the main causes of patient mortality in TSCC; therefore, it is necessary to elucidate the mechanism by which TSCC metastasis is regulated. In the present study, the early growth response 1 (Egr-1) expression in TSCC was analyzed based on GEO datasets and the effect of Egr-1 in TSCC tumor cell migration and invasion was measured using Transwell assay. By overexpressing dual-specificity protein phosphatase 1 (DUSP1) in cells with Egr-1 knockdown using lentivirus infection, the role of DUSP1 in Egr-1-regulated TSCC cell migration and invasion was determined. By using luciferase and ChIP assays, the mechanism behind how DUSP1 is regulated by Egr-1 was detected. In the present study, it was demonstrated that Egr-1 was downregulated in TSCC and the knockdown of Egr-1 increased TSCC cell migration and invasion. The expression of Egr-1 was also correlated with DUSP1. The overexpression of DUSP1 in Egr-1 knockdown cells, reduced the level of cell migration and invasion. Furthermore, it was demonstrated that knockdown of Egr-1 inhibited the promoter activity of DUSP1 and the site through which Egr-1 regulates DUSP1 transcription was identified. In conclusion, the present study demonstrated that Egr-1 regulates TSCC cell migration and invasion through modulating DUSP1, suggesting the potential of Egr-1 and DUSP1 as therapy targets for TSCC.

TNF-α-induced down-regulation of type I interferon receptor contributes to acquired resistance of cervical squamous cancer to Cisplatin

We aimed to investigate the effects of tumor necrosis factor (TNF)-α on the expression of interferon α/β receptor subunit 1 (IFNAR1) and cervical squamous cancer (CSCC) resistance to Cisplatin, as well as the underlying mechanisms. Kaplan-Meier analysis was used to plot the overall survival curves. SiHa cells were treated with 20 ng/ml TNF-α to determine cell proliferation in human CSCC cells and the expression of IFNAR1. The effects of TNF-α on the downstream signaling pathway, including casein kinase 1α (CK1α), were investigated using the caspase protease inhibitor FK009, the c-Jun kinase inhibitor SP600125, and the nuclear factor kappa-B inhibitor ammonium pyrrolidinedithiocarbamate (PDTC). TNF-α induced down-regulation of IFNAR1 in human CSCC cells and promoted proliferation of SiHa cells. SiHa cells were transfected with the catalytic inactive mutant CK1α K49A, and the ability of TNF-α to induce down-regulation of IFNAR1 expression was found to be significantly diminished in this context. FK009 and PDTC had no obvious effect on the expression of CK1α, however, SP600125 significantly reduced the expression of CK1α in the presence of TNF-α. SiHa cells treated with TNF-α showed reduced sensitivity to Cisplatin and exhibited higher cell viability, while the sensitivity of SiHa cells to Cisplatin was restored after treatment with CK1α inhibitor D4476. Additionally, we constructed a TNF-α overexpressing SiHa cell line and a transplanted tumor model. The results were similar to those of in vitro efficacy. We demonstrate that TNF-α-induced down-regulation of type I interferon receptor contributes to acquired resistance of cervical squamous cancer to Cisplatin.

Pien-tze-huang promotes wound healing in streptozotocin-induced diabetes models associated with improving oxidative stress via the Nrf2/ARE pathway

Diabetic foot ulcers are a serious complication of diabetes, with high mortality and a lack of effective clinical treatment, which leads to a considerable financial burden. Pien-Tze-Huang (PZH) is a Chinese traditional medicine with a long history that has been found to be an effective and convenient treatment for inflammatory diseases such as skin abscesses and ulcers. In this study, we assessed the effects of PZH on diabetic wounds and the underlying mechanisms. The wounds were established on the backs of streptozotocin-induced type 1 diabetic rats and type 2 diabetic mouse models. We found that PZH treatment used locally or by gavage significantly promoted wound healing, accelerated re-epithelialization and vasculature in the wound tissue, upregulated the expression of the growth factors VEGF-A, PDGF, and EGF, and activated the Nrf2/ARE pathway in the wound tissue. In vitro assays showed that PZH improved the proliferation, migration and angiogenic function of human umbilical vein endothelial cells (HUVECs) cultured in palmitic acid, reduced the expression of the apoptotic proteins p53, Bax, and cleaved-caspase3, and activated Nrf2/ARE signaling; however, these protective effects were abrogated after Nrf2 was knocked down by specific siRNA. In addition, the levels of the serum inflammatory cytokines IL-1β, TNF-α, and IL-6 were reduced after PZH gavage treatment. In conclusion, the positive role of PZH in diabetic wound healing might be related to the activation of the Nrf2/ARE pathway to regulate the level of oxidative stress in vivo and increase the expression of growth factors to improve angiogenesis.

Tumor necrosis factor α impedes colonic thiamin pyrophosphate and free thiamin uptake: involvement of JNK/ERK1/2-mediated pathways

The aim of this study was to examine the effect of TNFα (i.e., a predominant proinflammatory cytokine produced during chronic gut inflammation) on colonic uptake of thiamin pyrophosphate (TPP) and free thiamin, forms of vitamin B1 that are produced by the gut microbiota and are absorbed via distinct carrier-mediated systems. We utilized human-derived colonic epithelial CCD841 and NCM460 cells, human differentiated colonoid monolayers, and mouse intact colonic tissue preparations together with an array of cellular/molecular approaches in our investigation. The results showed that exposure of colonic epithelial cells to TNFα leads to a significant inhibition in TPP and free thiamin uptake. This inhibition was associated with: 1) a significant suppression in the level of expression of the colonic TPP transporter (cTPPT; encoded by SLC44A4), as well as thiamin transporters-1 & 2 (THTR-1 & -2; encoded by SLC19A2 & SLC19A3, respectively); 2) marked inhibition in activity of the SLC44A4, SLC19A2, and SLC19A3 promoters; and 3) significant suppression in level of expression of nuclear factors that are needed for activity of these promoters (i.e., CREB-1, Elf-3, NF-1A, SP-1). Furthermore, the inhibitory effects were found to be mediated via JNK and ERK1/2 signaling pathways. We also examined the level of expression of cTPPT and THTR-1 & -2 in colonic tissues of patients with active ulcerative colitis and found the levels to be significantly lower than in healthy controls. These findings demonstrate that exposure of colonocytes to TNFα suppresses TPP and free thiamin uptake at the transcriptional level via JNK- and Erk1/2-mediated pathways.

Gene delivery of chitosan-graft-polyethyleneimine vectors loaded on scaffolds for nerve regeneration

As an important transcription factor, c-Jun could upregulate growth factors expression in Schwann cells (SCs). Arginine-Glycine-Aspartate (RGD)-functionalized chitosan-graft-polyethyleneimine (RCP) gene vectors were prepared through the maleic anhydride & the carbodiimide methods, and electrostatically bound with c-Jun plasmids (pJUN), finally loaded on poly-L-lactic acid/silk fibroin parallel fiber films to fabricate nerve scaffold (RCP/pJUN-PSPF@PGA), which could locally deliver c-Jun plasmids into SCs via the mediation of RGD peptides, and upregulate the expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in SCs. After the scaffold was bridged in sciatic nerve defect, the delivery of c-Jun plasmids from RCP/pJUN-PSPF@PGA facilitated SCs to sustain the expressions of NGF, BDNF and vascular endothelial growth factor in the injury field, promoting myelination, axonal growth and microvascular generation and nerve regeneration, muscle reinnervation and functional recovery. These results suggested that RCP/pDNA-PSPF@PGA, as an effective gene delivery platform, could provide a local gene therapy to improve nerve regeneration.

Glycogen Synthase Kinase 3β Involvement in Neuroinflammation and Neurodegenerative Diseases

BACKGROUND

GSK-3β activity has been strictly related to neuroinflammation and neurodegeneration. Alzheimer's disease is the most studied neurodegenerative disease, but GSK-3β seems to be involved in almost all neurodegenerative diseases including Parkinson's disease, amyotrophic lateral sclerosis, frontotemporal dementia, Huntington's disease and the autoimmune disease multiple sclerosis.

OBJECTIVE

The aim of this review is to help researchers both working on this research topic or not to have a comprehensive overview on GSK-3β in the context of neuroinflammation and neurodegeneration.

METHOD

Literature has been searched using PubMed and SciFinder databases by inserting specific keywords. A total of more than 500 articles have been discussed.

RESULTS

First of all, the structure and regulation of the kinase were briefly discussed and then, specific GSK-3β implications in neuroinflammation and neurodegenerative diseases were illustrated also with the help of figures, to conclude with a comprehensive overview on the most important GSK-3β and multitarget inhibitors. For all discussed compounds, the structure and IC50 values at the target kinase have been reported.

CONCLUSION

GSK-3β is involved in several signaling pathways both in neurons as well as in glial cells and immune cells. The fine regulation and interconnection of all these pathways are at the base of the rationale use of GSK-3β inhibitors in neuroinflammation and neurodegeneration. In fact, some compounds are now under clinical trials. Despite this, pharmacodynamic and ADME/Tox profiles of the compounds were often not fully characterized and this is deleterious in such a complex system.

Difluoromethylornithine Induces Apoptosis through Regulation of AP-1 Signaling via JNK Phosphorylation in Epithelial Ovarian Cancer

Difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase (ODC), has promising activity against various cancers and a tolerable safety profile for long-term use as a chemopreventive agent. However, the anti-tumor effects of DFMO in ovarian cancer cells have not been entirely understood. Our study aimed to identify the effects and mechanism of DFMO in epithelial ovarian cancer cells using SKOV-3 cells. Treatment with DFMO resulted in a significantly reduced cell viability in a time- and dose-dependent manner. DFMO treatment inhibited the activity and downregulated the expression of ODC in ovarian cancer cells. The reduction in cell viability was reversed using polyamines, suggesting that polyamine depletion plays an important role in the anti-tumor activity of DFMO. Additionally, significant changes in Bcl-2, Bcl-xL, Bax protein levels, activation of caspase-3, and cleavage of poly (ADP-ribose) polymerase were observed, indicating the apoptotic effects of DFMO. We also found that the effect of DFMO was mediated by AP-1 through the activation of upstream JNK via phosphorylation. Moreover, DFMO enhanced the effect of cisplatin, thus showing a possibility of a synergistic effect in treatment. In conclusion, treatment with DFMO alone, or in combination with cisplatin, could be a promising treatment for ovarian cancer.

Transcriptional Regulation of Thrombin-Induced Endothelial VEGF Induction and Proangiogenic Response

Thrombin, the ligand of the protease-activated receptor 1 (PAR1), is a well-known stimulator of proangiogenic responses in vascular endothelial cells (ECs), which are mediated through the induction of vascular endothelial growth factor (VEGF). However, the transcriptional events underlying this thrombin-induced VEGF induction and angiogenic response are less well understood at present. As reported here, we conducted detailed promotor activation and signal transduction pathway studies in human microvascular ECs, to decipher the transcription factors and the intracellular signaling events underlying the thrombin and PAR-1-induced endothelial VEGF induction. We found that c-FOS is a key transcription factor controlling thrombin-induced EC VEGF synthesis and angiogenesis. Upon the binding and internalization of its G-protein-coupled PAR-1 receptor, thrombin triggers ERK1/2 signaling and activation of the nuclear AP-1/c-FOS transcription factor complex, which then leads to VEGF transcription, extracellular secretion, and concomitant proangiogenic responses of ECs. In conclusion, exposure of human microvascular ECs to thrombin triggers signaling through the PAR-1–ERK1/2–AP-1/c-FOS axis to control VEGF gene transcription and VEGF-induced angiogenesis. These observations offer a greater understanding of endothelial responses to thromboinflammation, which may help to interpret the results of clinical trials tackling the conditions associated with endothelial injury and thrombosis.

MicroRNA-139-5p upregulation is associated with diabetic endothelial cell dysfunction by targeting c-jun

Dysfunction of endothelial cells (ECs) and their progenitor cells is an important feature of diabetic vascular disease. MicroRNA (miR)-139-5p is involved in inhibiting the metastasis and progression of diverse malignancies. However, the role of miR-139-5p in ECs still remains unclarified. Here we demonstrated that miR-139-5p expression was elevated in endothelial colony-forming cells (ECFCs) isolated from patients with diabetes, ECs derived from the aorta of diabetic rodents, and human umbilical vein endothelial cells (HUVECs) cultured in high glucose media. MiR-139-5p mimics inhibited tube formation, migration, proliferation, and down-regulated expression of c-jun, vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF)-B, in ECFCs and HUVECs, respectively; moreover, miR-139-5p inhibitors reversed the tendency. Further, gain- and-loss function experiments and ChIP assay indicated that miR-139-5p regulate functions of ECFCs by targeting c-jun-VEGF/PDGF-B pathway. In vivo experiments (Matrigel plug assay and hindlimb ischemia model) showed that miR-139-5p downregulation further promoted ECFC-mediated angiogenesis and blood perfusion. In conclusion, diabetes-mediated high miR-139-5p expression inhibits the c-jun-VEGF/PDGF-B pathway, thus decreasing ECFCs migration, tube formation and proliferation, which subsequently reduces ECs survival. Therefore, miR-139-5p might be an important therapeutic target in the treatment of diabetic vasculopathy in the future.

Epithelioid hemangioma of bone harboring FOS and FOSB gene rearrangements: A clinicopathologic and molecular study

The diagnosis of epithelioid hemangioma (EH) remains challenging due to its rarity, worrisome histologic features, and locally aggressive clinical and radiographic presentation. Especially in the bone, EH can be misdiagnosed as a malignant vascular neoplasm due its lytic, often destructive or multifocal growth, as well as atypical morphology. The discovery of recurrent FOS and FOSB gene fusions in the pathogenesis of most EH has strengthened its stand-alone classification, distinct from other malignant epithelioid vascular lesions, such as epithelioid hemangioendothelioma or angiosarcoma. In this study we investigate a group of molecularly confirmed skeletal EH by the presence of FOS or FOSB gene rearrangements to better define its clinical and pathologic characteristics within a homogenous molecular subset. The cohort included 38 patients (25 males, 13 females), with a mean age at diagnosis of 38 years (range, 4-75). Regional, multifocal presentation was noted in 10 cases. Only six cases were correctly recognized as EH by the referring institutions, while most were misdiagnosed as other vascular tumors. Of the 17 patients with follow-up data available, five patients (29%) developed local recurrence after marginal en bloc excision (n = 3) or curettage (n = 2). Local recurrence-free survival rates were 84% at 3 years and 38% at 5 years. No metastasis or disease-related death was identified. Imaging studies exhibited no specific features, showing cortical bone destruction and soft-tissue extension in 14 (38%) cases. FOS gene rearrangements were detected in 28 (74%) of cases, while FOSB rearrangements in 10 (26%) cases. Our results highlight the significant challenges encountered in establishing a correct diagnosis exclusive of the molecular testing, mainly due to its overlap to other malignant epithelioid vascular tumors. Skeletal EH emerges as a genetically defined locally aggressive vascular neoplasm, with a high rate of local recurrence, but lacking the propensity for distant spread.

TNF-α controls Lipocalin-2 expression in PC-3 prostate cancer cells

Prostate cancer (PCa) is one of the most common and deadly cancers in men worldwide. The surrounding tumor microenvironment (TME) is important in tumor progression, as cytokines and soluble mediators including tumor necrosis factor (TNF-α) or lipocalin-2 (LCN2) can influence tumor growth and formation of metastasis. The exact mechanisms on how these pleiotropic factors affect PCa are still unknown. In this study, we showed for the first time that LCN2 mRNA and protein expression are strongly inducible by TNF-α in the highly metastatic human PCa cell line PC-3. In addition, we observed higher levels of secreted LCN2 in cell culture medium of TNF-α-treated PC-3 cells. We found that different signaling pathways such as p38, NF-κB or JNK were activated shortly after TNF-α treatment. Moreover, the mRNA levels of IL-1β and IL-8 were also significantly increased after 24 h stimulation. Mechanistically, the NF-κB pathway and the JNK signaling axis are directly responsible for LCN2 upregulation. This was shown by the fact that pretreatment with the JNK inhibitors SP600125 or JNK-IN-8 strongly downregulated phosphorylation of c-Jun protein and markedly reduced TNF-α-mediated LCN2 upregulation in PC-3 cells. Likewise, the NF-κB inhibitor QNZ was able to repress TNF-α-induced LCN2 expression in PC-3 cells. Taking into consideration that LCN2 has been described as a tumor promoting factor in PCa, our results indicate that JNK regulates LCN2 expression and unmasks the JNK signaling axis as a possible therapeutic target for patients with PCa.

Hyperglycemia Associated Metabolic and Molecular Alterations in Cancer Risk, Progression, Treatment, and Mortality

Cancer and diabetes are amongst the leading causes of deaths worldwide. There is an alarming rise in cancer incidences and mortality, with approximately 18.1 million new cases and 9.6 million deaths in 2018. A major contributory but neglected factor for risk of neoplastic transformation is hyperglycemia. Epidemiologically too, lifestyle patterns resulting in high blood glucose level, with or without the role of insulin, are more often correlated with cancer risk, progression, and mortality. The two conditions recurrently exist in comorbidity, and their interplay has rendered treatment regimens more challenging by restricting the choice of drugs, affecting surgical consequences, and having associated fatal complications. Limited comprehensive literature is available on their correlation, and a lack of clarity in understanding in such comorbid conditions contributes to higher mortality rates. Hence, a critical analysis of the elements responsible for enhanced mortality due to hyperglycemia-cancer concomitance is warranted. Given the lifestyle changes in the human population, increasing metabolic disorders, and glucose addiction of cancer cells, hyperglycemia related complications in cancer underline the necessity for further in-depth investigations. This review, therefore, attempts to shed light upon hyperglycemia associated factors in the risk, progression, mortality, and treatment of cancer to highlight important mechanisms and potential therapeutic targets.

Expanding the Spectrum of Genetic Alterations in Pseudomyogenic Hemangioendothelioma With Recurrent Novel ACTB-FOSB Gene Fusions

Pseudomyogenic hemangioendothelioma (PHE) is an uncommon, rarely metastasizing vascular neoplasm with predilection to affect young adults. The tumors often present as multiple nodules involving various tissue planes, including superficial and deep soft tissues as well as bone. Recurrent SERPINE1-FOSB gene fusions have been reported as the hallmark genetic abnormality in PHE, however, in our experience, a number of cases with typical histology lack this genetic abnormality. In this study, we identify a novel ACTB-FOSB gene fusion, which is as prevalent as the initial translocation reported. We selected 15 consecutive cases of PHE with typical morphologic features which had material for molecular testing. The cohort included 10 males and 5 females, ranging in age from 17 to 58 years (median age: 33 y; mean age: 35.3 y). Eight (53%) cases were located in the lower extremities (foot, calf, tibia, thigh), 5 (33%) were located in the trunk, abdomen or pelvis (abdominal wall-2, shoulder, back, ischium) and 2 (13%) were located in the upper extremity (humerus and hand). Ten (67%) cases had multifocal presentation and 5 (33%) presented as solitary lesions. Three (20%) cases were located only in the superficial dermis and subcutaneous tissues, 4 (27%) involved the superficial and deep soft tissue and 8 (53%) cases involved only the deep soft tissue and bone. Using fluorescence in situ hybridization and ARCHER fusionplex analysis we identified a novel ACTB-FOSB gene fusion in 7 cases, while the remaining 8 had the previously described SERPINE1-FOSB fusion. The clinicopathologic features and behavior of PHE associated with the ACTB-FOSB gene fusion were similar to those harboring the SERPINE1-FOSB; except that tumors with the ACTB variant were more often associated with solitary presentation. In conclusion, our results expand the spectrum of genetic alterations in PHE with a novel gene fusion identified in half of the cases. We speculate that some of the novel targeted therapies that have shown promise in SERPINE1-FOSB-positive PHE might also be beneficial in this molecular subset.

The role of AP-1 in self-sufficient proliferation and migration of cancer cells and its potential impact on an autocrine/paracrine loop

Activating protein-1 (AP-1) family members, especially Fra-1 and c-Jun, are highly expressed in invasive cancers and can mediate enhanced migration and proliferation. The aim of this study was to explore the significance of elevated levels of AP-1 family members under conditions that restrict growth. We observed that invasive MDA-MB-231 cells express high levels of Fra-1, c-Jun, and Jun-D during serum starvation and throughout the cell cycle compared to non-tumorigenic and non-invasive cell lines. We then analyzed Fra-1 levels in additional breast and other cancer cell lines. We found breast and lung cancer cells with higher levels of Fra-1 during serum starvation had relatively higher ability to proliferate and migrate under these conditions. Utilizing a dominant negative construct of AP-1, we demonstrated that proliferation and migration of MDA-MB-231 in the absence of serum requires AP-1 activity. Finally, we observed that MDA-MB-231 cells secrete factors(s) that induce Fra-1 expression and migration in non-tumorigenic and non-metastatic cells and that both the expression of and response to these factors require AP-1 activity. These results suggest the presence of an autocrine/paracrine loop that maintains high Fra-1 levels in aggressive cancer cells, enhancing their proliferative and metastatic ability and affecting neighbors to alter the tumor environment.

The MAPK-activator protein-1 signaling regulates changes in lung tissue of rat exposed to hypobaric hypoxia

This study reports the role of MAPKs (JNK, ERK, and p38), and activator protein-1 (AP-1) transcription factor in the hypobaric hypoxia induced change in lung tissue. Healthy male Sprague-Dawley rats were exposed to hypobaric hypoxia for 6, 12, 24, 48, 72, and 120 hr. Hypoxia resulted in significant increase in reactive oxygen species (ROS), vascular endothelial growth factor (VEGF) and decreased nitric oxide (NO), these act as signaling molecules for activation of MAPK and also contribute in development of vascular leakage (an indicator of pulmonary edema) as confirmed by histological studies. Our results confirmed JNK activation as an immediate early response (peaked at 6-48 hr), activation of ERKs (peaked at 24-72 hr) and p38 (peaked at 72-120 hr) as a secondary response to hypoxia. The MAPK pathway up regulated its downstream targets phospho c-Jun (peaked at 6-120 hr), JunB (peaked at 24-120 hr) however, decreased c-Fos, and JunD levels. DNA binding activity also confirmed activation of AP-1 transcription factor in lung tissue under hypobaric hypoxia. Further, we analyzed the proliferative and inflammatory genes regulated by different subunits of AP-1 to explore its role in vascular leakage. Increased expression of cyclin D1 (peaked at 12-72 hr) and p16 level (peaked at 48-120 hr) were correlated to the activation of c-jun, c-Fos and JunB. Administration of NFκB inhibitor caffeic acid phenethyl ester (CAPE) and SP600125 (JNK inhibitor) had no effect on increased levels of Interferon-γ (IFN-γ), Interleukin-1 (IL-1), and Tumor Necrosis Factor-α (TNF-α) thereby confirming the involvement of AP-1 as well as NFκB in inflammation. Expression of c-jun, c-Fos were correlated with activation of proliferative genes and JunB, Fra-1 with pro-inflammatory cytokines. In conclusion immediate response to hypobaric hypoxia induced c-Jun:c-Fos subunits of AP-1; responsible for proliferation that might cause inhomogeneous vasoconstriction leading to vascular leakage and inflammation at increased duration of hypobaric hypoxia exposure.

APE1 modulates cellular responses to organophosphate pesticide-induced oxidative damage in non-small cell lung carcinoma A549 cells

Monocrotophos (MCP) and chlorpyrifos (CP) are widely used organophosphate pesticides (OPPs), speculated to be linked with human pathologies including cancer. Owing to the fact that lung cells are most vulnerable to the environmental toxins, the development and progression of lung cancer can be caused by the exposure of OPPs. The present study investigates the oxidative DNA damage response evoked by MCP and CP in human non-small cell lung carcinoma A549 cells. A549 cells were exposed to MCP and CP; cytotoxicity and reactive oxygen species (ROS) generation were measured to select the non-toxic dose. In order to establish whether MCP and CP can initiate the DNA repair and cell survival signalling pathways in A549 cells, qRT-PCR and Western blotting techniques were used to investigate the mRNA and protein expression levels of DNA base excision repair (BER)-pathway enzymes and transcription factors (TFs) involved in cell survival mechanisms. A significant increase in cell viability and ROS generation was observed when exposed to low and moderate doses of MCP and CP at different time points (24, 48 and 72 h) studied. A549 cells displayed a dose-dependent accumulation of apurinic/apyrimidinic (AP) sites after 24 h exposure to MCP advocating for the activation of AP endonuclease-mediated DNA BER-pathway. Cellular responses to MCP- and CP-induced oxidative stress resulted in an imbalance in the mRNA and protein expression of BER-pathway enzymes, viz. PARP1, OGG1, APE1, XRCC1, DNA pol β and DNA ligase III α at different time points. The treatment of OPPs resulted in the upregulation of TFs, viz. Nrf2, c-jun, phospho-c-jun and inducible nitric oxide synthase. Immunofluorescent confocal imaging of A549 cells indicated that MCP and CP induces the translocation of APE1 within the cytoplasm at an early 6 h time point, whereas it promotes nuclear localization after 24 h of treatment, which suggests that APE1 subcellular distribution is dynamically regulated in response to OPP-induced oxidative stress. Furthermore, nuclear colocalization of APE1 and the TF c-jun was observed in response to the treatment of CP and MCP for different time points in A549 cells. Therefore, in this study we demonstrate that MCP- and CP-induced oxidative stress alters APE1-dependent BER-pathway and also mediates cell survival signalling mechanisms via APE1 regulation, thereby promoting lung cancer cell survival and proliferation.

Increased Hypothalamic Levels of Endozepines, Endogenous Ligands of Benzodiazepine Receptors, in a Rat Model of Sepsis

BACKGROUND

The mechanisms involved in septic anorexia are mainly related to the secretion of inflammatory cytokines. The term endozepines designates a family of neuropeptides, including the octadecaneuropeptide (ODN), originally isolated as endogenous ligands of benzodiazepine receptors. Previous data showed that ODN, produced and released by astrocytes, is a potent anorexigenic peptide. We have studied the effect of sepsis by means of a model of cecal ligation and puncture (CLP) on the hypothalamic expression of endozepines (DBI mRNA and protein levels), as well as on the level of neuropeptides controlling energy homeostasis mRNAs: pro-opiomelanocortin, neuropeptide Y, and corticotropin-releasing hormone. In addition, we have investigated the effects of two inflammatory cytokines, TNF-α and IL-1β, on DBI mRNA levels in cultured rat astrocytes.

METHODS

Studies were performed on Sprague-Dawley male rats and on cultures of rat cortical astrocytes. Sepsis was induced using the CLP method. Sham-operated control animals underwent the same procedure, but the cecum was neither ligated nor incised.

RESULTS

Sepsis caused by CLP evoked an increase of DBI mRNA levels in ependymal cells bordering the third ventricle and in tanycytes of the median eminence. CLP-induced sepsis was also associated with stimulated ODN-like immunoreactivity (ODN-LI) in the hypothalamus. In addition, TNF-α, but not IL-1β, induced a dose-dependent increase in DBI mRNA in cultured rat astrocytes. An increase in the mRNA encoding the precursor of the anorexigenic peptide α-melanocyte stimulating hormone, the pro-opiomelanocortin, and the corticotropin-releasing hormone was observed in the hypothalamus.

CONCLUSION

These results suggest that during sepsis, hypothalamic mRNA encoding endozepines, anorexigenic peptide as well as stress hormone could play a role in the anorexia/cachexia associated with inflammation due to sepsis and we suggest that this hypothalamic mRNA expression could involve TNF-α.

The mTOR/AP-1/VEGF signaling pathway regulates vascular endothelial cell growth

Vascular restenosis is a common adverse event following percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). The atypical Ser/Thr protein kinase mammalian target of rapamycin (mTOR) plays an important role in cell differentiation and apoptosis. Vascular restenosis caused by excessive endothelial cell proliferation can be inhibited by local application of the mTOR inhibitor rapamycin (RAPA); however, RAPA can also suppress normal vascular endothelial cell growth by blocking mTOR/VEGF signaling, although the underlying mechanism is still unclear. Here, endogenous mTOR, AP-1, and VEGF were inhibited or overexpressed to investigate the mechanism underlying the effects of RAPA. Inhibition of AP-1 or mTOR with AP-1-siRNA or RAPA treatment respectively, decreased vascular endothelial cell proliferation, upregulation of AP-1 or mTOR increased cell proliferation, and VEGF overexpression increased, while RAPA-induced mTOR inhibition decreased vascular endothelial cell proliferation, the results indicate that combining mTOR downregulation and VEGF upregulation might both inhibit restenosis and maintain normal vascular endothelial cell growth after PCI or CABG, suggest the mTOR/AP-1/VEGF pathway might play a crucial role in regulating vascular endothelial cell growth.

AP-1 confers resistance to anti-cancer therapy by activating XIAP

The underlying cause of treatment failure in many cancer patients is intrinsic and acquired resistance to chemotherapy. Recently, histone deacetylase (HDAC) inhibitors have developed into a promising cancer treatment. However, resistance mechanism induced by HDAC inhibitors remains largely unknown. Here we report that a HDAC inhibitor, JNJ-2648158 induced transcription of XIAP by activating AP-1 expression, which conferring resistance to chemotherapeutics. Our results showed that high expression of c-Fos caused by HDAC inhibitor promoted AP-1 formation during acquired resistance towards chemo-drugs, indicating an extremely poor clinical outcome in breast cancers and liver cancers. Our study reveals a novel regulatory mechanism towards chemo-drug resistance, and suggests that XIAP may serve as a potential therapeutic target in those chemo-resistant cancer cells.

APE1 modulates cellular responses to organophosphate pesticide-induced oxidative damage in non-small cell lung carcinoma A549 cells

Monocrotophos (MCP) and chlorpyrifos (CP) are widely used organophosphate pesticides (OPPs), speculated to be linked with human pathologies including cancer. Owing to the fact that lung cells are most vulnerable to the environmental toxins, the development and progression of lung cancer can be caused by the exposure of OPPs. The present study investigates the oxidative DNA damage response evoked by MCP and CP in human non-small cell lung carcinoma A549 cells. A549 cells were exposed to MCP and CP; cytotoxicity and reactive oxygen species (ROS) generation were measured to select the non-toxic dose. In order to establish whether MCP and CP can initiate the DNA repair and cell survival signalling pathways in A549 cells, qRT-PCR and Western blotting techniques were used to investigate the mRNA and protein expression levels of DNA base excision repair (BER)-pathway enzymes and transcription factors (TFs) involved in cell survival mechanisms. A significant increase in cell viability and ROS generation was observed when exposed to low and moderate doses of MCP and CP at different time points (24, 48 and 72 h) studied. A549 cells displayed a dose-dependent accumulation of apurinic/apyrimidinic (AP) sites after 24 h exposure to MCP advocating for the activation of AP endonuclease-mediated DNA BER-pathway. Cellular responses to MCP- and CP-induced oxidative stress resulted in an imbalance in the mRNA and protein expression of BER-pathway enzymes, viz. PARP1, OGG1, APE1, XRCC1, DNA pol β and DNA ligase III α at different time points. The treatment of OPPs resulted in the upregulation of TFs, viz. Nrf2, c-jun, phospho-c-jun and inducible nitric oxide synthase. Immunofluorescent confocal imaging of A549 cells indicated that MCP and CP induces the translocation of APE1 within the cytoplasm at an early 6 h time point, whereas it promotes nuclear localization after 24 h of treatment, which suggests that APE1 subcellular distribution is dynamically regulated in response to OPP-induced oxidative stress. Furthermore, nuclear colocalization of APE1 and the TF c-jun was observed in response to the treatment of CP and MCP for different time points in A549 cells. Therefore, in this study we demonstrate that MCP- and CP-induced oxidative stress alters APE1-dependent BER-pathway and also mediates cell survival signalling mechanisms via APE1 regulation, thereby promoting lung cancer cell survival and proliferation.

Role of NOD- like Receptors in Glioma Angiogenesis: Insights into future therapeutic interventions

Gliomas are the most common solid tumors among central nervous system tumors. Most glioma patients succumb to their disease within two years of the initial diagnosis. The median survival of gliomas is only 14.6 months, even after aggressive therapy with surgery, radiation, and chemotherapy. Gliomas are heavily infiltrated with myeloid- derived cells and endothelial cells. Increasing evidence suggests that these myeloid- derived cells interact with tumor cells promoting their growth and migration. NLRs (nucleotide-binding oligomerization domain (NOD)-containing protein like receptors) are a class of pattern recognition receptors that are critical to sensing pathogen and danger associated molecular patterns. Mutations in some NLRs lead to autoinflammatory diseases in humans. Moreover, dysregulated NLR signaling is central to the pathogenesis of several cancers, autoimmune and neurodegenerative diseases. Our review explores the role of angiogenic factors that contribute to upstream or downstream signaling pathways leading to NLRs. Angiogenesis plays a significant role in the pathogenesis of variety of tumors including gliomas. Though NLRs have been detected in several cancers including gliomas and NLR signaling contributes to angiogenesis, the exact role and mechanism of involvement of NLRs in glioma angiogenesis remain largely unexplored. We discuss cellular, molecular and genetic studies of NLR signaling and convergence of NLR signaling pathways with angiogenesis signaling in gliomas. This may lead to re-appropriation of existing anti-angiogenic therapies or development of future strategies for targeted therapeutics in gliomas.

Convergent Transcription of Interferon-stimulated Genes by TNF-α and IFN-α Augments Antiviral Activity against HCV and HEV

IFN-α has been used for decades to treat chronic hepatitis B and C, and as an off-label treatment for some cases of hepatitis E virus (HEV) infection. TNF-α is another important cytokine involved in inflammatory disease, which can interact with interferon signaling. Because interferon-stimulated genes (ISGs) are the ultimate antiviral effectors of the interferon signaling, this study aimed to understand the regulation of ISG transcription and the antiviral activity by IFN-α and TNF-α. In this study, treatment of TNF-α inhibited replication of HCV by 71 ± 2.4% and HEV by 41 ± 4.9%. Interestingly, TNF-α induced the expression of a panel of antiviral ISGs (2-11 fold). Blocking the TNF-α signaling by Humira abrogated ISG induction and its antiviral activity. Chip-seq data analysis and mutagenesis assay further revealed that the NF-κB protein complex, a key downstream element of TNF-α signaling, directly binds to the ISRE motif in the ISG promoters and thereby drives their transcription. This process is independent of interferons and JAK-STAT cascade. Importantly, when combined with IFN-α, TNF-α works cooperatively on ISG induction, explaining their additive antiviral effects. Thus, our study reveals a novel mechanism of convergent transcription of ISGs by TNF-α and IFN-α, which augments their antiviral activity against HCV and HEV.

Frequent FOS Gene Rearrangements in Epithelioid Hemangioma: A Molecular Study of 58 Cases With Morphologic Reappraisal

Epithelioid hemangioma (EH) is a unique benign vasoformative tumor composed of epithelioid endothelial cells. Although a small subset of EHs with atypical features harbor ZFP36-FOSB fusions, no additional genetic abnormalities have been found to date in the remaining cases. On the basis of a novel FOS-LMNA gene fusion identified by RNA sequencing in an index case of a skeletal EH with typical morphology, we sought to investigate the prevalence of FOS rearrangement in a large cohort of EHs. Thus 57 additional EH cases lacking FOSB rearrangements were studied for FOS gene abnormalities by fluorescence in situ hybridization, and results were correlated with morphologic appearance and clinical presentation. The EHs were subclassified as typical (n=25), cellular (n=21), and angiolymphoid hyperplasia with eosinophilia (ALHE) (n=12) variants. The ALHE was defined as an EH with a vascular "blow-out" pattern associated with a variable degree of inflammation. There were 17 (29%) cases bearing FOS gene rearrangements among 58 cases tested, including 12 male and 5 female patients, with a mean age of 42 years. Most FOS-rearranged EHs occurred in the bone (10) and soft tissue (6), whereas only 1 case was cutaneous. The predominant anatomic site was the extremity (12), followed by trunk (3), head and neck (1), and penis (1). The incidence of FOS rearrangement was significantly higher in bone (59%, P=0.006) and lower in head and neck (5%, P=0.009). Twelve of the FOS-rearranged cases were cellular EH (P=0.001) associated with moderate mitotic activity (2 to 5/10 HPF) and milder inflammatory background. All 12 ALHE cases lacked FOS gene abnormalities, suggesting different pathogenesis. In conclusion, FOS rearrangement was present in a third of EHs across different locations and histologic variants; however, it was more prevalent in cellular EH and intraosseous lesions, compared with those in skin, soft tissue, and head and neck. This genetic abnormality can be useful in challenging cases, to distinguish cellular EHs from malignant epithelioid vascular tumors. These results also suggest that dysregulation of the FOS family of transcription factors through chromosomal translocation is as a key event in the tumorigenesis of EH except for the ALHE variant.

Roles of PI3K/Akt and c-Jun signaling pathways in human papillomavirus type 16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and in vitro angiogenesis in non-small cell lung cancer cells

Background and Objectives

Human papillomavirus (HPV)-16 infection may be related to non-smoking associated lung cancer. Our previous studies have found that HPV-16 oncoproteins promoted angiogenesis via enhancing hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) expression in non-small cell lung cancer (NSCLC) cells. In this study, we further investigated the roles of PI3K/Akt and c-Jun signaling pathways in it.

Methods

Human NSCLC cell lines, A549 and NCI-H460, were stably transfected with pEGFP-16 E6 or E7 plasmids. Western blotting was performed to analyze the expression of HIF-1α, p-Akt, p-P70S6K, p-P85S6K, p-mTOR, p-JNK, and p-c-Jun proteins. VEGF and IL-8 protein secretion and mRNA levels were determined by ELISA and Real-time PCR, respectively. The invitro angiogenesis was observed by human umbilical vein endothelial cells (HUVECs) tube formation assay. Co-immunoprecipitation was performed to analyze the interaction between c-Jun and HIF-1α.

Results

HPV-16 E6 and E7 oncoproteins promoted the activation of Akt, P70S6K, P85S6K, mTOR, JNK, and c-Jun. LY294002, a PI3K inhibitor, inhibited HPV-16 oncoprotein-induced activation of Akt, P70S6K, and P85S6K, expression of HIF-1α, VEGF, and IL-8, and invitro angiogenesis. c-Jun knockdown by specific siRNA abolished HPV-16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and invitro angiogenesis. Additionally, HPV-16 oncoproteins promoted HIF-1α protein stability via blocking proteasome degradation pathway, but c-Jun knockdown abrogated this effect. Furthermore, HPV-16 oncoproteins increased the quantity of c-Jun binding to HIF-1α.

Conclusions

PI3K/Akt signaling pathway and c-Jun are involved in HPV-16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and invitro angiogenesis. Moreover, HPV-16 oncoproteins promoted HIF-1α protein stability possibly through enhancing the interaction between c-Jun and HIF-1α, thus making a contribution to angiogenesis in NSCLC cells.

The roles of Wnt5a, JNK and paxillin in the occurrence of metastasis of pancreatic adenocarcinoma

BACKGROUND

Wnt5a, p-JNK and p-paxillin proteins have been shown to be associated with the development of several types of cancer. Here we studied the role of Wnt5a, p-JNK and p-paxillin protein expressions and functions in the further development of pancreatic adenocarcinoma.

METHODS

Fresh tissue samples from adjacent and malignant portions were obtained after operation from 58 patients with pancreatic adenocarcinoma. Wnt5a, p-JNK1, JNK1, paxillin and p-paxillin were detected with immunohistochemical staining.

RESULTS

The expressions of Wnt5a, p-JNK1 and p-paxillin were higher in malignant tissues than in adjacent portions (p < 0.01), where JNK1 and paxillin were absent (p > 0.05). The expression levels of Wnt5a, p-JNK1 and p-paxillin in tumor tissues were correlated with each other (r = 0.564, 0.586 and 0.737, respectively). The expression of Wnt5a in tumor tissue could independently predict the occurrence of lymph node involvement [odds ratio (OR) 8.19, 95 % confidence interval (CI) 2.47-27.19]. The expression of p-JNK1 in tumor tissue was an independent predictor of peritoneal metastasis (OR 4.01, 95 % CI 1.32-12.17).

CONCLUSION

Wnt5a/JNK signaling might be activated in pancreatic cancer. Wnt5a is the specific predictor for lymph node involvement.

Bradykinin promotes vascular endothelial growth factor expression and increases angiogenesis in human prostate cancer cells

Prostate cancer is the most commonly diagnosed malignancy in men and shows a tendency for metastasis to distant organs. Angiogenesis is required for metastasis. Bradykinin (BK) is an inflammatory mediator involved in tumor growth and metastasis, but its role in vascular endothelial growth factor (VEGF) expression and angiogenesis in human prostate cancer remains unknown. The aim of this study was to examine whether BK promotes prostate cancer angiogenesis via VEGF expression. We found that exogenous BK increased VEGF expression in prostate cancer cells and further promoted tube formation in endothelial progenitor cells and human umbilical vein endothelial cells. Pretreatment of prostate cancer with B2 receptor antagonist or small interfering RNA (siRNA) reduced BK-mediated VEGF production. The Akt and mammalian target of rapamycin (mTOR) pathways were activated after BK treatment, and BK-induced VEGF expression was abolished by the specific inhibitor and siRNA of the Akt and mTOR cascades. BK also promoted nuclear factor-κB (NF-κB) and activator protein 1 (AP-1) activity. Importantly, BK knockdown reduced VEGF expression and abolished prostate cancer cell conditional medium-mediated angiogenesis. Taken together, these results indicate that BK operates through the B2 receptor, Akt, and mTOR, which in turn activate NF-κB and AP-1, activating VEGF expression and contributing to angiogenesis in human prostate cancer cells.

Role of JunB in adenosine A2B receptor-mediated vascular endothelial growth factor production

Interstitial adenosine stimulates neovascularization in part through A2B adenosine receptor-dependent upregulation of vascular endothelial growth factor (VEGF). In the current study, we tested the hypothesis that A2B receptors upregulate JunB, which can contribute to stimulation of VEGF production. Using the human microvascular endothelial cell line, human mast cell line, mouse cardiac Sca1-positive stromal cells, and mouse Lewis lung carcinoma (LLC) cells, we found that adenosine receptor-dependent upregulation of VEGF production was associated with an increase in VEGF transcription, activator protein-1 (AP-1) activity, and JunB accumulation in all cells investigated. Furthermore, the expression of JunB, but not the expression of other genes encoding transcription factors from the Jun family, was specifically upregulated. In LLC cells expressing A2A and A2B receptor transcripts, only the nonselective adenosine agonist NECA (5'-N-ethylcarboxamidoadenosine), but not the selective A2A receptor agonist CGS21680 [2-p-(2-carboxyethyl) phenylethylamino-5'-N-ethylcarboxamidoadenosine], significantly increased JunB reporter activity and JunB nuclear accumulation, which were inhibited by the A2B receptor antagonist PSB603 [(8-[4-[4-((4-chlorophenzyl)piperazide-1-sulfonyl)phenyl]]-1-propylxanthine]. Using activators and inhibitors of intracellular signaling, we demonstrated that A2B receptor-dependent accumulation of JunB protein and VEGF secretion share common intracellular pathways. NECA enhanced JunB binding to the murine VEGF promoter, whereas mutation of the high-affinity AP-1 site (-1093 to -1086) resulted in a loss of NECA-dependent VEGF reporter activity. Finally, NECA-dependent VEGF secretion and reporter activity were inhibited by the expression of a dominant negative JunB or by JunB knockdown. Thus, our data suggest an important role of the A2B receptor-dependent upregulation of JunB in VEGF production and possibly other AP-1-regulated events.

A kinase-independent function of CDK6 links the cell cycle to tumor angiogenesis

In contrast to its close homolog CDK4, the cell cycle kinase CDK6 is expressed at high levels in lymphoid malignancies. In a model for p185BCR-ABL+ B-acute lymphoid leukemia, we show that CDK6 is part of a transcription complex that induces the expression of the tumor suppressor p16INK4a and the pro-angiogenic factor VEGF-A. This function is independent of CDK6's kinase activity. High CDK6 expression thus suppresses proliferation by upregulating p16INK4a, providing an internal safeguard. However, in the absence of p16INK4a, CDK6 can exert its full tumor-promoting function by enhancing proliferation and stimulating angiogenesis. The finding that CDK6 connects cell-cycle progression to angiogenesis confirms CDK6's central role in hematopoietic malignancies and could underlie the selection pressure to upregulate CDK6 and silence p16INK4a.

TNF-α decreases VEGF secretion in highly polarized RPE cells but increases it in non-polarized RPE cells related to crosstalk between JNK and NF-κB pathways

Asymmetrical secretion of vascular endothelial growth factor (VEGF) by retinal pigment epithelial (RPE) cells in situ is critical for maintaining the homeostasis of the retina and choroid. VEGF is also involved in the development and progression of age-related macular degeneration (AMD). We studied the effect of tumor necrosis factor-α (TNF-α) on the secretion of VEGF in polarized and non-polarized RPE cells (P-RPE cells and N-RPE cells, respectively) in culture and in situ in rats. A subretinal injection of TNF-α caused a decrease in VEGF expression and choroidal atrophy. Porcine RPE cells were seeded on Transwell™ filters, and their maturation and polarization were confirmed by the asymmetrical VEGF secretion and trans electrical resistance. Exposure to TNF-α decreased the VEGF secretion in P-RPE cells but increased it in N-RPE cells in culture. TNF-α inactivated JNK in P-RPE cells but activated it in N-RPE cells, and TNF-α activated NF-κB in P-RPE cells but not in N-RPE cells. Inhibition of NF-κB activated JNK in both types of RPE cells indicating crosstalk between JNK and NF-κB. TNF-α induced the inhibitory effects of NF-κB on JNK in P-RPE cells because NF-κB is continuously inactivated. In N-RPE cells, however, it was not evident because NF-κB was already activated. The basic activation pattern of JNK and NF-κB and their crosstalk led to opposing responses of RPE cells to TNF-α. These results suggest that VEGF secretion under inflammatory conditions depends on cellular polarization, and the TNF-α-induced VEGF down-regulation may result in choroidal atrophy in polarized physiological RPE cells. TNF-α-induced VEGF up-regulation may cause neovascularization by non-polarized or non-physiological RPE cells.

High glucose induces vascular endothelial growth factor production in human synovial fibroblasts through reactive oxygen species generation

BACKGROUND

Diabetes is an independent risk factor of osteoarthritis (OA). Angiogenesis is essential for the progression of OA. Here, we investigated the intracellular signaling pathways involved in high glucose (HG)-induced vascular endothelial growth factor (VEGF) expression in human synovial fibroblast cells.

METHODS

HG-mediated VEGF expression was assessed with qPCR and ELISA. The mechanisms of action of HG in different signaling pathways were studied using Western blotting. Knockdown of proteins was achieved by transfection with siRNA. Chromatin immunoprecipitation assays were used to study in vivo binding of c-Jun to the VEGF promoter.

RESULTS

Stimulation of OA synovial fibroblasts (OASF) with HG induced concentration- and time-dependent increases in VEGF expression. Treatment of OASF with HG increased reactive oxygen species (ROS) generation. Pretreatment with NADPH oxidase inhibitor (APO or DPI), ROS scavenger (NAC), PI3K inhibitor (Ly294002 or wortmannin), Akt inhibitor, or AP-1 inhibitor (curcumin or tanshinone IIA) blocked the HG-induced VEGF production. HG also increased PI3K and Akt activation. Treatment of OASF with HG increased the accumulation of phosphorylated c-Jun in the nucleus, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the VEGF promoter.

CONCLUSIONS

Our results suggest that the HG increases VEGF expression in human synovial fibroblasts via the ROS, PI3K, Akt, c-Jun and AP-1 signaling pathway.

GENERAL SIGNIFICANCE

We link high glucose on VEGF expression in osteoarthritis.

TNFα and Fas/FasL pathways are involved in 9-Methoxycamptothecin-induced apoptosis in cancer cells with oxidative stress and G2/M cell cycle arrest

9-Methoxycamptothecin (MCPT) has been recently reported to have a strong anticancer activity. However, its detailed mechanism of action in human cancer cells has not been well clarified. The results showed that MCPT induced cytotoxicity in seven human cancer cell lines in a dose dependent manner after 72h, with A2780 and Hela cell lines more sensitive, so the two cell lines were chosen to do further studies. MCPT induced strong G2/M arrest in both A2780 cells and Hela cells after 24h, following by substantial sub-G1 arrest (indicating apoptosis). The apoptosis was verified by staining with Annexin V-FITC and propidium iodide. ROS generation increased significantly in MCPT-induced apoptosis. Meanwhile, the apoptosis appeared to be dependent on caspase-3, -8 and -9 in A2780 cells, and caspase-3 in Hela cells. In addition, MCPT induced up-regulation expression of most of seventeen genes in both cell lines. Western blot verified that changes of TNFα, Fas, P53 and P27 protein level were consistent with their gene expression changes. Taken together, MCPT plays an important role in tumor growth suppression by inducing apoptosis in both cell lines via extrinsic and intrinsic apoptotic pathways, and has the potential to be developed into an antitumor agent.

Loss of SPARC in bladder cancer enhances carcinogenesis and progression

Secreted protein acidic and rich in cysteine (SPARC) has been implicated in multiple aspects of human cancer. However, its role in bladder carcinogenesis and metastasis are unclear,with some studies suggesting it may be a promoter and others arguing the opposite. Using a chemical carcinogenesis model in Sparc-deficient mice and their wild-type littermates, we found that loss of SPARC accelerated the development of urothelial preneoplasia (atypia and dysplasia), neoplasia, and metastasis and was associated with decreased survival. SPARC reduced carcinogen-induced inflammation and accumulation of reactive oxygen species as well as urothelial cell proliferation. Loss of SPARC was associated with an inflammatory phenotype of tumor-associated macrophages and fibroblasts, with concomitant increased activation of urothelial and stromal NF-κB and AP1 in vivo and in vitro. Syngeneic spontaneous and experimental metastasis models revealed that tumor- and stroma-derived SPARC reduced tumor growth and metastasis through inhibition of cancer-associated inflammation and lung colonization. In human bladder tumor tissues, the frequency and intensity of SPARC expression were inversely correlated with disease-specific survival. These results indicate that SPARC is produced by benign and malignant compartments of bladder carcinomas where it functions to suppress bladder carcinogenesis, progression, and metastasis.

Interleukin-6 induces vascular endothelial growth factor expression and promotes angiogenesis through apoptosis signal-regulating kinase 1 in human osteosarcoma

Osteosarcoma is characterized by a high malignant and metastatic potential. Angiogenesis is essential for the caner metastasis. Interleukin-6 (IL-6) is a multifunctional cytokine that is associated with the disease status and outcomes of cancers. However, the relationship between IL-6 and vascular endothelial growth factor (VEGF) expression in human osteosarcoma is mostly unknown. Here we found that the IL-6 and VEGF expression was correlated with tumor stage and significantly higher than that in normal bone. Incubation of osteosarcoma cells with IL-6 increased VEGF mRNA and protein expression. Pretreatment of cells with IL-6R antibody reduced IL-6-mediated VEGF production. The apoptosis signal-regulating kinase 1 (ASK1)/p38/AP-1 pathway was activated after IL-6 treatment, and IL-6-induced VEGF expression was abolished by the specific inhibitor and siRNA of ASK1, p38, and AP-1 cascades. Importantly, knockdown IL-6 reduced VEGF expression and abolished osteosarcoma conditional medium-mediated angiogenesis. Taken together, these results indicate that IL-6 occurs through ASK1 and p38, which in turn activates AP-1, resulting in the activations of VEGF expression and contributing the angiogenesis of human osteosarcoma cells.

Growth of the pancreatic cancer cell line PANC-1 is inhibited by protein phosphatase 2A inhibitors through overactivation of the c-Jun N-terminal kinase pathway

Protein phosphatase 2A (PP2A) is a multimeric serine/threonine phosphatase that can dephosphorylate multiple kinases. It is generally considered to be a cancer suppressor as its inhibition can induce phosphorylation and activation of substrate kinases that mainly accelerate growth. We previously reported that cantharidin, an active constituent of a traditional Chinese medicine, potently and selectively inhibited PP2A, yet efficiently repressed the growth of pancreatic cancer cells through activation of the c-Jun N-terminal kinase (JNK) pathway. This suggested that activation of kinase pathways might also be a potential strategy for cancer therapy. In this study, we have confirmed that the basal activity of the phospatidylinositol 3-kinase (PI3K)/JNK/activator protein 1 (AP-1) pathway promoted pancreatic cancer cell growth when stimulated by growth factors. Interestingly, although treatment with the PP2A inhibitors, cantharidin or okadaic acid (OA), amplified the PI3K-dependent activation of JNK, cell growth was repressed. We therefore hypothesised that a specific level of activity of the JNK pathway might be required to maintain the promitogenic function, as both repression and overactivation of JNK could inhibit cell proliferation. It was found that the JNK-dependent growth inhibition was independent of the activation of AP-1, but dependent on the repression of Akt. Although the PP2A inhibitors triggered overactivation of JNK and inhibited cell growth, excessively activated protein kinase C (PKC) improved cell survival. Combined treatment with a PP2A inhibitor and a PKC inhibitor produced a synergistic effect, which indicates a potentially promising therapeutic approach to pancreatic cancer treatment.

Impact of SOCS3 overexpression on human skeletal muscle development in vitro

The Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling cascade has been identified as a crucial factor for myogenesis. The STAT3 isoform is essential for satellite cell migration and myogenic differentiation as it mediates the expression of muscle specific myogenic factors. The SOCS (suppressors of cytokine signaling) family of proteins down-regulates STAT activation. Primary human skeletal muscle cells were isolated and cultured to investigate the effect of SOCS3 adenoviral overexpression on myotube maturation. It was demonstrated that STAT3 inhibition did not influence myotube development or survival. Moreover, SOCS3 overexpression enhances the mRNA expression of downstream targets of STAT3, c-FOS and VEGF. These increases were correlated with enhanced mRNA expression of genes associated with muscle maturation and hypertrophy. Thus SOCS3 influences myoblast differentiation and SOCS3 may be significant in regulating the activity of genes previously identified as transcriptionally regulated by STAT3.

A novel role for TNFAIP2: its correlation with invasion and metastasis in nasopharyngeal carcinoma

Tumor necrosis factor alpha (TNFα) is an inflammatory cytokine that is present in the microenvironment of many tumors and is known to promote tumor progression. To examine how TNFα modulates the progression and metastasis of nasopharyngeal carcinoma, we used Affymetrix chips to identify TNFα-inducible genes that are dysregulated in this tumor. Elevated expression of TNFAIP2, which encodes TNFα-inducible protein 2 and not previously known to be associated with cancer, was found and confirmed by quantitative RT-PCR of TNFAIP2 expression in nasopharyngeal carcinoma and adjacent normal tissues. Immunohistochemical analysis showed that the TNFAIP2 protein was highly expressed in tumor cells. Analysis of 95 nasopharyngeal carcinoma biopsy specimens revealed that high TNFAIP2 expression was significantly correlated with high-level intratumoral microvessel density (P=0.005) and low distant metastasis-free survival (P=0.001). A multivariate analysis further confirmed that TNFAIP2 was an independent prognostic factor for nasopharyngeal carcinoma (P=0.002). In vitro, TNFα treatment of nasopharyngeal carcinoma HK1 cells was found to induce TNFAIP2 expression, and siRNA-based knockdown of TNFAIP2 dramatically reduced the migration and invasion of nasopharyngeal carcinoma HK1 cells. These results collectively suggest for the first time that TNFAIP2 is a cell migration-promoting protein and its expression predicts distant metastasis. Our data suggest that TNFAIP2 may serve as an independent prognostic indicator for nasopharyngeal carcinoma.

Tumor necrosis factor α stimulates endothelin-1 synthesis in rat hepatic stellate cells in hepatic wound healing through a novel IKK/JNK pathway

Endothelin-1 (ET-1), a potent vasoconstrictor peptide up-regulated during wound healing and fibrosis, induces myofibroblasts to contract tissue. Here we have used a liver injury model to test the hypothesis that TNFα may be an important stimulator of ET-1 production in hepatic wound healing. We examined primary rat hepatic stellate cells, isolated from either normal or injured livers and used standard methodology to measure preproET-1 mRNA and mature ET-1 peptide, specific kinases, and preproET-1 promoter activity. Chromatin immunoprecipitation analysis was used to determine basal binding of transcription factors to the preproET-1 promoter. TNFα induced preproET-1 expression in activated hepatic stellate cells in a c-Jun N-terminal kinase (JNK)/AP-1-dependent fashion. TNFα activated JNK through an IκB kinase (IKK) pathway, which activated the transcriptional factor, c-Jun, leading to preproET-1 promoter mediated ET-1 transcription. The TNFα mediated induction of ET-1 synthesis also had functional effects, specifically mediating autocrine induced stellate cell contraction. TNFα stimulated activated stellate cells to produce ET-1 via a novel IKK-JNK-dependent signaling pathway. The resulting autocrine functional effects of ET-1 are likely to be important in the wound-healing process.

Heme oxygenase-1/carbon monoxide induces vascular endothelial growth factor expression via p38 kinase-dependent activation of Sp1

Heme oxygenase-1 (HO-1) is a stress-inducible enzyme catalyzing the oxidative degradation of heme to free iron, CO, and biliverdin. Previous studies demonstrated that HO-1 overexpression promoted VEGF expression and angiogenesis in the ischemic heart. However, the underlying mechanism remained elusive. Here we show that adenovirus-mediated HO-1 transduction of rat primary cardiomyocytes and H9C2 myocytes resulted in significant induction of VEGF expression, and a similar effect was seen in cells directly exposed to CO gas or a CO-releasing compound, tricarbonyldichlororuthenium (II) dimer. HO-1/CO-induced VEGF expression was significantly suppressed by pharmacological inhibition of p38 kinase, but not of AKT, activation. VEGF promoter-luciferase reporter assays, electrophoretic mobility shift assays, supershift assay, and chromatin immunoprecipitation showed that CO-induced VEGF promoter activation requires the binding of the Sp1 transcriptional factor to a cis-regulatory sequence located at the VEGF promoter. Western blot analysis and immunostaining experiments demonstrated that HO-1/CO induced p38-dependent phosphorylation of Sp1 at Thr-453 and Thr-739 both in vitro and in vivo. Overexpression of Sp1 protein with an alanine mutation at Thr-453 or Thr-739 suppressed CO-induced Sp1 binding to the VEGF promoter and its transcriptional activation. Collectively, these data suggest that p38-dependent phosphorylation of Sp1 at Thr-453/Thr-739 is crucial for HO-1/CO-induced VEGF expression in myocytes.

Randomized phase III trial of tamoxifen versus thalidomide in women with biochemical-recurrent-only epithelial ovarian, fallopian tube or primary peritoneal carcinoma after a complete response to first-line platinum/taxane chemotherapy with an evaluation of serum vascular endothelial growth factor (VEGF): A Gynecologic Oncology Group Study

PURPOSE

To compare progression-free survival (PFS), overall survival (OS) and toxicities of thalidomide versus tamoxifen and to evaluate serum vascular endothelial growth factor (VEGF) in biochemical-recurrent epithelial ovarian cancer, primary peritoneal cancer or fallopian tube carcinoma (EOC/PPC/FTC).

METHODS

Biochemical recurrence was defined as a rising CA-125 exceeding twice the upper limit of normal without evidence of disease as defined by RECIST 1.0 criteria. Women with FIGO stages III and IV, histologically confirmed EOC/PPC/FTC who were free of disease following first-line chemotherapy were randomized to oral thalidomide 200mg daily with escalation to a maximum of 400 mg or tamoxifen 20mg orally twice daily for up to 1 year, progression or adverse effect prohibited further treatment. VEGF was quantified by ELISA in pre and post-treatment serum.

RESULTS

Of the 139 women randomized, 138 were eligible. Interim analysis showed that thalidomide did not reduce the recurrence rate relative to tamoxifen, and the trial was closed. Thalidomide versus tamoxifen was associated with a similar risk of progression (HR = 1.31, 95% confidence interval [CI] = 0.93-1.85), an increased risk of death (HR = 1.76, 95% CI = 1.16-2.68) and more grades 3 and 4 toxicities (55% versus 3%). The most common grades 3 and 4 toxicities were constitutional (12%), somnolence (12%), pulmonary (9%), venous thromboembolism (VTE) (6%) and peripheral neurologic (6%) for thalidomide, with VTE (1.4%) and gastrointestinal (1.4%) for tamoxifen. Serum VEGF was not associated with clinical characteristics, treatment, PFS or OS.

CONCLUSION

Thalidomide was not more effective than tamoxifen in delaying recurrence or death but was more toxic. VEGF was not prognostic in this cohort.

Maternal dietary choline deficiency alters angiogenesis in fetal mouse hippocampus

We examined whether maternal dietary choline modulates angiogenesis in fetal brain. Pregnant C57BL/6 mice were fed either a choline-deficient (CD), control (CT), or choline-supplemented diet (CS) from days 12 to 17 (E12-17) of pregnancy and then fetal brains were studied. In CD fetal hippocampus, proliferation of endothelial cells (EC) was decreased by 32% (p < 0.01 vs. CT or CS) while differentiated EC clusters (expressing factor VIII related antigen (RA)) increased by 25% (p < 0.01 vs. CT or CS). These changes were associated with > 25% decrease in the number of blood vessels in CD fetal hippocampus (p < 0.01 vs. CT and CS), with no change in total cross-sectional area of these blood vessels. Expression of genes for the angiogenic signals derived from both endothelial and neuronal progenitor cells (NPC) was increased in CD fetal hippocampus VEGF C (Vegfc), 2.0-fold, p < 0.01 vs. CT and angiopoietin 2 (Angpt2), 2.1-fold, (p < 0.01 vs. CT)). Similar increased expression was observed in NPC isolated from E14 fetal mouse brains and exposed to low (5 microM), CT (70 microM), or high choline (280 microM) media for 72 h (low choline caused a 9.7-fold increase in relative gene expression of Vegfc (p < 0.001 vs. CT and high) and a 3.4-fold increase in expression of Angpt2, (p < 0.05 vs. CT and high). ANGPT2 protein was increased 42.2% (p < 0.01). Cytosine-phosphate-guanine dinucleotide islands in the proximity of the promoter areas of Vegfc and Angpt2 were hypomethylated in low choline NPC compared to CT NPC (p < 0.01). We conclude that maternal dietary choline intake alters angiogenesis in the developing fetal hippocampus.