A novel Ca2+/calmodulin antagonist HBC inhibits angiogenesis and down-regulates hypoxia-inducible factor

Calcium and Non-Penetrating Traumatic Brain Injury: A Proposal for the Implementation of an Early Therapeutic Treatment for Initial Head Insults

Finding an effective treatment for traumatic brain injury is challenging for multiple reasons. There are innumerable different causes and resulting levels of damage for both penetrating and non-penetrating traumatic brain injury each of which shows diverse pathophysiological progressions. More concerning is that disease progression can take decades before neurological symptoms become obvious. Currently, the primary treatment for non-penetrating mild traumatic brain injury, also called concussion, is bed rest despite the fact the majority of emergency room visits for traumatic brain injury are due to this mild form. Furthermore, one-third of mild traumatic brain injury cases progress to long-term serious symptoms. This argues for the earliest therapeutic intervention for all mild traumatic brain injury cases which is the focus of this review. Calcium levels are greatly increased in damaged brain regions as a result of the initial impact due to tissue damage as well as disrupted ion channels. The dysregulated calcium level feedback is a diversity of ways to further augment calcium neurotoxicity. This suggests that targeting calcium levels and function would be a strong therapeutic approach. An effective calcium-based traumatic brain injury therapy could best be developed through therapeutic programs organized in professional team sports where mild traumatic brain injury events are common, large numbers of subjects are involved and professional personnel are available to oversee treatment and documentation. This review concludes with a proposal with that focus.

Downregulated calmodulin expression contributes to endothelial cell impairment in diabetes

Endothelial dysfunction, a central hallmark of cardiovascular pathogenesis in diabetes mellitus, is characterized by impaired endothelial nitric oxide synthase (eNOS) and NO bioavailability. However, the underlying mechanisms remain unclear. Here in this study, we aimed to identify the role of calmodulin (CaM) in diabetic eNOS dysfunction. Human umbilical vein endothelial cells and murine endothelial progenitor cells (EPCs) treated with high glucose (HG) exhibited downregulated CaM mRNA/protein and vascular endothelial growth factor (VEGF) expression with impeded eNOS phosphorylation and cell migration/tube formation. These perturbations were reduplicated in CALM1-knockdown cells but prevented in CALM1-overexpressing cells. EPCs from type 2 diabetes animals behaved similarly to HG-treated normal EPCs, which could be rescued by CALM1-gene transduction. Consistently, diabetic animals displayed impaired eNOS phosphorylation, endothelium-dependent dilation, and CaM expression in the aorta, as well as deficient physical interaction of CaM and eNOS in the gastrocnemius. Local CALM1 gene delivery into a diabetic mouse ischemic hindlimb improved the blunted limb blood perfusion and gastrocnemius angiogenesis, and foot injuries. Diabetic patients showed insufficient foot microvascular autoregulation, eNOS phosphorylation, and NO production with downregulated CaM expression in the arterial endothelium, and abnormal CALM1 transcription in genome-wide sequencing analysis. Therefore, our findings demonstrated that downregulated CaM expression is responsible for endothelium dysfunction and angiogenesis impairment in diabetes, and provided a novel mechanism and target to protect against diabetic endothelial injury.

Chloroquine prevents hypoxic accumulation of HIF-1α by inhibiting ATR kinase: implication in chloroquine-mediated chemosensitization of colon carcinoma cells under hypoxia

BACKGROUND

Chloroquine (CQ) is an effective and safe antimalarial drug that is also used as a disease-modifying antirheumatic drug. Recent studies have shown that CQ can sensitize cancer cells to anti-cancer therapies.

METHODS

In this study, we investigated the molecular mechanisms underlying CQ-mediated chemosensitization in human colon carcinoma cells.

RESULTS

CQ prevented hypoxia-inducible factor (HIF)-1α protein induction in human colon carcinoma cells. CQ also suppressed HIF-1 activity, as represented by CQ inhibition of HIF-1-dependent luciferase activity and reduced induction of vascular endothelial growth factor. Under hypoxia, CQ restricted HIF-1α synthesis but did not affect HIF-1α transcription and protein stability. The hypoxic state activated ataxia telangiectasia and Rad3-related (ATR) kinase and increased the level of phosphorylated checkpoint kinase 1, a substrate of ATR kinase; however, this was prevented by CQ. An ATR kinase inhibitor suppressed the hypoxic induction of HIF-1α protein and was as effective as CQ. The cytotoxicity of 5-fluorouracil (5-FU), the first choice for the treatment of colorectal cancer, was attenuated under hypoxia. CQ enhanced the cytotoxicity of 5-FU treatment, which was mimicked by the transient transfection with HIF-1α siRNA.

CONCLUSIONS

Under hypoxia, CQ-mediated sensitization of colon carcinoma HCT116 cells to 5-FU involves HIF-1 inhibition via ATR kinase suppression.

Calmodulin binding proteins and neuroinflammation in multiple neurodegenerative diseases

Calcium dysregulation (“Calcium Hypothesis”) is an early and critical event in Alzheimer’s and other neurodegenerative diseases. Calcium binds to and regulates the small regulatory protein calmodulin that in turn binds to and regulates several hundred calmodulin binding proteins. Initial and continued research has shown that many calmodulin binding proteins mediate multiple events during the onset and progression of Alzheimer’s disease, thus establishing the “Calmodulin Hypothesis”. To gain insight into the general applicability of this hypothesis, the involvement of calmodulin in neuroinflammation in Alzheimer’s, amyotrophic lateral sclerosis, Huntington’s disease, Parkinson’s disease, frontotemporal dementia, and other dementias was explored. After a literature search for calmodulin binding, 11 different neuroinflammatory proteins (TREM2, CD33, PILRA, CR1, MS4A, CLU, ABCA7, EPHA1, ABCA1, CH3L1/YKL-40 and NLRP3) were scanned for calmodulin binding domains using the Calmodulin Target Database. This analysis revealed the presence of at least one binding domain within which visual scanning demonstrated the presence of valid binding motifs. Coupled with previous research that identified 13 other neuroinflammation linked proteins (BACE1, BIN1, CaMKII, PP2B, PMCA, NOS, NMDAR, AchR, Ado A2AR, Aβ, APOE, SNCA, TMEM175), this work shows that at least 24 critical proteins involved in neuroinflammation are putative or proven calmodulin binding proteins. Many of these proteins are linked to multiple neurodegenerative diseases indicating that calmodulin binding proteins lie at the heart of neuroinflammatory events associated with multiple neurodegenerative diseases. Since many calmodulin-based pharmaceuticals have been successfully used to treat Huntington’s and other neurodegenerative diseases, these findings argue for their immediate therapeutic implementation.

Advances in Intracellular Calcium Signaling Reveal Untapped Targets for Cancer Therapy

Intracellular Ca2+ distribution is a tightly regulated process. Numerous Ca2+ chelating, storage, and transport mechanisms are required to maintain normal cellular physiology. Ca2+-binding proteins, mainly calmodulin and calbindins, sequester free intracellular Ca2+ ions and apportion or transport them to signaling hubs needing the cations. Ca2+ channels, ATP-driven pumps, and exchangers assist the binding proteins in transferring the ions to and from appropriate cellular compartments. Some, such as the endoplasmic reticulum, mitochondria, and lysosomes, act as Ca2+ repositories. Cellular Ca2+ homeostasis is inefficient without the active contribution of these organelles. Moreover, certain key cellular processes also rely on inter-organellar Ca2+ signaling. This review attempts to encapsulate the structure, function, and regulation of major intracellular Ca2+ buffers, sensors, channels, and signaling molecules before highlighting how cancer cells manipulate them to survive and thrive. The spotlight is then shifted to the slow pace of translating such research findings into anticancer therapeutics. We use the PubMed database to highlight current clinical studies that target intracellular Ca2+ signaling. Drug repurposing and improving the delivery of small molecule therapeutics are further discussed as promising strategies for speeding therapeutic development in this area.

Featuring how calcium channels and calmodulin affect glioblastoma behavior. A review article

Glioblastoma (GBM) is considered to be the most aggressive primary brain tumor with an extremely bad prognosis. Recurrence after treatment is a major problem with a survival rate for one year ranging about 39.7%. Ideal outcomes are still difficult to be achieved despite the recent treatment combinations. The ultimate capacity to regrow after resection is considered to be related to the availability of self-regenerating populations of stem cells. We made a literature review interpreting how calcium channels and calcium-regulated proteins mechanistically elaborate glioblastoma virulence in different ways. Calcium channels, and calcium-regulated proteins have shown diverse interconnected roles in shaping different aspects of GBM biology as indicated in some experimental studies. The beneficial prospective of those roles granting GBM different aggressive potentials pose variable applications in targeted therapy whether it is experimental or clinical trials.

Calmodulin Binding Proteins and Alzheimer's Disease: Biomarkers, Regulatory Enzymes and Receptors That Are Regulated by Calmodulin

The integral role of calmodulin in the amyloid pathway and neurofibrillary tangle formation in Alzheimer’s disease was first established leading to the “Calmodulin Hypothesis”. Continued research has extended our insight into the central function of the small calcium sensor and effector calmodulin and its target proteins in a multitude of other events associated with the onset and progression of this devastating neurodegenerative disease. Calmodulin’s involvement in the contrasting roles of calcium/CaM-dependent kinase II (CaMKII) and calcineurin (CaN) in long term potentiation and depression, respectively, and memory impairment and neurodegeneration are updated. The functions of the proposed neuronal biomarker neurogranin, a calmodulin binding protein also involved in long term potentiation and depression, is detailed. In addition, new discoveries into calmodulin’s role in regulating glutamate receptors (mGluR, NMDAR) are overviewed. The interplay between calmodulin and amyloid beta in the regulation of PMCA and ryanodine receptors are prime examples of how the buildup of classic biomarkers can underly the signs and symptoms of Alzheimer’s. The role of calmodulin in the function of stromal interaction molecule 2 (STIM2) and adenosine A2A receptor, two other proteins linked to neurodegenerative events, is discussed. Prior to concluding, an analysis of how targeting calmodulin and its binding proteins are viable routes for Alzheimer’s therapy is presented. In total, calmodulin and its binding proteins are further revealed to be central to the onset and progression of Alzheimer’s disease.

Repositioning of the antipsychotic drug TFP for sepsis treatment

Abstract

Sepsis is a disease responsible for the death of almost all critical patients. Once infected by virus or bacteria, patients can die due to systemic inflammation within a short period of time. Cytokine storm plays an essential role in causing organ dysfunction and septic shock. Thus, inhibition of cytokine secretion is considered very important in sepsis therapy. In this study, we found that TFP, an antipsychotic drug mainly used to treat schizophrenia by suppressing dopamine secretion, inhibited cytokine release from activated immune cells both in vitro and in vivo. Trifluoperazine (TFP) decreased the levels of pro-inflammatory cytokines without altering their transcription level. In LPS-induced endotoxemia and cecal content injection (CCI) models, TFP intraperitoneal administration improved survival rate. Thus, TFP was considered to inhibit the secretion of proteins through a mechanism similar to that of W7, a calmodulin inhibitor. Finally, we confirmed that TFP treatment relieved organ damage by estimating the concentrations of aspartate transaminase (AST), alanine transaminase (ALT), and blood urea nitrogen (BUN) in the serum. Our findings were regarded as a new discovery of the function of TFP in treating sepsis patients.

Key messages

• TFP inhibits LPS-induced activation of DCs by suppressing pro-inflammatory cytokine.

• Treatment of TFP increases survival of LPS-induced endotoxemia and CCI sepsis models.

• TFP exerted a protective effect against tissue or organ damage in animal models.

Electronic supplementary material

The online version of this article (10.1007/s00109-019-01762-4) contains supplementary material, which is available to authorized users.

Computer Simulation of TSP1 Inhibition of VEGF-Akt-eNOS: An Angiogenesis Triple Threat

The matricellular protein thrombospondin-1 (TSP1) is a potent inhibitor of angiogenesis. Specifically, TSP1 has been experimentally shown to inhibit signaling downstream of vascular endothelial growth factor (VEGF). The molecular mechanism of this inhibition is not entirely clear. We developed a detailed computational model of VEGF signaling to Akt-endothelial nitric oxide synthase (eNOS) to investigate the quantitative molecular mechanism of TSP1 inhibition. The model demonstrated that TSP1 acceleration of VEGFR2 degradation is sufficient to explain the inhibition of VEGFR2 and eNOS phosphorylation. However, Akt inhibition requires TSP1-induced phosphatase recruitment to VEGFR2. The model was then utilized to test various strategies for the rescue of VEGF signaling to Akt and eNOS. Inhibiting TSP1 was predicted to be not as effective as CD47 depletion in rescuing signaling to Akt. The model further predicts that combination strategy involving depletion of CD47 and inhibition of TSP1 binding to CD47 is necessary for effective recovery of signaling to eNOS. In all, computational modeling offers insight to molecular mechanisms involving TSP1 interaction with VEGF signaling and provides strategies for rescuing angiogenesis by targeting TSP1-CD47 axis.

Total Biosynthesis of Antiangiogenic Agent (-)-Terpestacin by Artificial Reconstitution of the Biosynthetic Machinery in Aspergillus oryzae

The total biosynthesis of (-)-terpestacin was achieved by heterologous expression of four biosynthetic enzyme genes ( tpcA- D) in Aspergillus oryzae. After construction of preterpestacin I by the action of bifunctional terpene synthase (TpcA), two cytochrome P450s (TpcBC) activate inert C-H bond to install three hydroxyl groups on the A-ring in stereo- and regioselective manners. Subsequently, a flavin-dependent oxidase (TpcD) catalyzes oxidation of the vicinal diol moiety to give a α-diketone, which undergoes an enolization to furnish terpestacin. The successful synthesis of structurally elaborated terpestacin showed that a reconstitution approach that harnesses several biosynthetic enzyme genes in A. oryzae could be a promising alternative to the current chemical synthesis of natural terpenoids.

Overexpression of hypoxia-inducible factor and metabolic pathways: possible targets of cancer

Cancer, the main cause of human deaths in the modern world is a group of diseases. Anticancer drug discovery is a challenge for scientists because of involvement of multiple survival pathways of cancer cells. An extensive study on the regulation of each step of these pathways may help find a potential cancer target. Up-regulated HIF-1 expression and altered metabolic pathways are two classical characteristics of cancer. Oxygen-dependent (through pVHL, PHDs, calcium-mediated) and independent (through growth factor signaling pathway, mdm2 pathway, HSP90) regulation of HIF-1α leads to angiogenesis, metastasis, and cell survival. The two subunits of HIF-1 regulates in the same fashion through different mechanisms. HIF-1α translation upregulates via mammalian target of rapamycin and mitogen-activated protein kinase signaling pathways, whereas HIF-1β through calmodulin kinase. Further, the stabilized interactions of these two subunits are important for proper functioning. Also, metabolic pathways crucial for the formation of building blocks (pentose phosphate pathway) and energy generation (glycolysis, TCA cycle and catabolism of glutamine) are altered in cancer cells to protect them from oxidative stress and to meet the reduced oxygen and nutrient supply. Up-regulated anaerobic metabolism occurs through enhanced expression of hexokinase, phosphofructokinase, triosephosphate isomerase, glucose 6-phosphate dehydrogenase and down-regulation of aerobic metabolism via pyruvate dehydrogenase kinase and lactate dehydrogenase which compensate energy requirements along with high glucose intake. Controlled expression of these two pathways through their common intermediate may serve as potent cancer target in future.

Identification of CALM as the potential serum biomarker for predicting the recurrence of nasopharyngeal carcinoma using a mass spectrometry-based comparative proteomic approach

To date, there are no serum biomarkers available for the prediction of recurrent nasopharyngeal carcinoma (rNPC). The diagnosis of rNPC mostly depends on imaging and biopsy of diseased tissue; however, both of these methods work mostly if the target tumor is at an advanced stage. Therefore, the identificaqtion of recurrent biomarkers is urgently required. In the present study, we used tandem mass tag (TMT) labeling and high performance liquid chromatography (HPLC) fractionation followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify differentially expressed proteins. Serum was collected from 40 patients with NPC [recurrence (n=20) and no recurrence (n=20)]. Compared to non-recurrent NPC (nrNPC), we found 59 proteins to be significantly dysregulated in rNPC; most of these have been previously reported to play a role in carcinogenesis. The dysregulation of calmodulin (CALM) was confirmed in 74 new patients [recurrence (n=32) and no recurrence (n=42)] by ELISA. Moreover, we performed a preliminary pathway analysis which revealed that oxidative phosphorylation was altered in the patients with rNPC compared to those with nrNPC. Taken together, these data identify a potential diagnostic biomarker for rNPC and elucidate the potential molecular mechanisms that are dysregulated and contribute to the pathogenesis of rNPC.

Differential effects of calcium on PI3K-Akt and HIF-1α survival pathways

Calcium signaling participates in the regulation of numberless cellular functions including cell cycle progression and cellular migration, important processes for cancer expansion. Cancer cell growth, migration, and invasion are typically supported by PI3K/Akt activation, while a hypoxic environment is critical in cancer development. Accordingly, in the present study, we aimed at investigating whether perturbations in calcium homeostasis induce alterations of HIF-1α and activate Akt levels in epithelial A549 and A431 cells. Survival was drastically reduced in the presence of calcium chelator BAPTA-AM and thapsigargin, a SERCA inhibitor inducing store-operated calcium entry, to a lesser extent. Calcium chelation provoked a transient but strong upregulation of HIF-1α protein levels and accumulation in the nucleus, whereas in the presence of thapsigargin, HIF-1α levels were rapidly abolished before reaching and exceeding control levels. Despite cell death, calcium chelation merely inhibited Akt, which was significantly activated in the presence of thapsigargin. Moreover, when store-operated calcium entry was simulated by reintroducing calcium ions in cell suspensions, Akt was rapidly activated in the absence of any growth factor. These data further underscore the growing importance of calcium entry and directly link this elementary event of calcium homeostasis to the Akt pathway, which is commonly deregulated in cancer.

Hydrazinobenzoylcurcumin inhibits androgen receptor activity and growth of castration-resistant prostate cancer in mice

There is a critical need for therapeutic agents that can target the amino-terminal domain (NTD) of androgen receptor (AR) for the treatment of castration-resistant prostate cancer (CRPC). Calmodulin (CaM) binds to the AR NTD and regulates AR activity. We discovered that Hydrazinobenzoylcurcumin (HBC), which binds exclusively to CaM, inhibited AR activity. HBC abrogated AR interaction with CaM, suppressed phosphorylation of AR Serine81, and blocked the binding of AR to androgen-response elements. RNA-Seq analysis identified 57 androgen-regulated genes whose expression was significantly (p ≤ 0.002) altered in HBC treated cells as compared to controls. Oncomine analysis revealed that genes repressed by HBC are those that are usually overexpressed in prostate cancer (PCa) and genes stimulated by HBC are those that are often down-regulated in PCa, suggesting a reversing effect of HBC on androgen-regulated gene expression associated with PCa. Ingenuity Pathway Analysis revealed a role of HBC affected genes in cellular functions associated with proliferation and survival. HBC was readily absorbed into the systemic circulation and inhibited the growth of xenografted CRPC tumors in nude mice. These observations demonstrate that HBC inhibits AR activity by targeting the AR NTD and suggest potential usefulness of HBC for effective treatment of CRPC.

Endothelin-1 activation of the endothelin B receptor modulates pulmonary endothelial CX3CL1 and contributes to pulmonary angiogenesis in experimental hepatopulmonary syndrome

Hepatic production and release of endothelin-1 (ET-1) binding to endothelin B (ETB) receptors, overexpressed in the lung microvasculature, is associated with accumulation of pro-angiogenic monocytes and vascular remodeling in experimental hepatopulmonary syndrome (HPS) after common bile duct ligation (CBDL). We have recently found that lung vascular monocyte adhesion and angiogenesis in HPS involve interaction of endothelial C-X3-C motif ligand 1 (CX3CL1) with monocyte CX3C chemokine receptor 1 (CX3CR1), although whether ET-1/ETB receptor activation influences these events is unknown. Our aim was to define if ET-1/ETB receptor activation modulates CX3CL1/CX3CR1 signaling and lung angiogenesis in experimental HPS. A selective ETB receptor antagonist, BQ788, was given for 2 weeks to 1-week CBDL rats. ET-1 (±BQ788) was given to cultured rat pulmonary microvascular endothelial cells overexpressing ETB receptors. BQ788 treatment significantly decreased lung angiogenesis, monocyte accumulation, and CX3CL1 levels after CBDL. ET-1 treatment significantly induced CX3CL1 production in lung microvascular endothelial cells, which was blocked by inhibitors of Ca(2+) and mitogen-activated protein kinase (MEK)/ERK pathways. ET-1-induced ERK activation was Ca(2+) independent. ET-1 administration also increased endothelial tube formation in vitro, which was inhibited by BQ788 or by blocking Ca(2+) and MEK/ERK activation. CX3CR1 neutralizing antibody partially inhibited ET-1 effects on tube formation. These findings identify a novel mechanistic interaction between the ET-1/ETB receptor axis and CX3CL1/CX3CR1 in mediating pulmonary angiogenesis and vascular monocyte accumulation in experimental HPS.

Targeting cell migration and the endoplasmic reticulum stress response with calmodulin antagonists: a clinically tested small molecule phenocopy of SEC62 gene silencing in human tumor cells

Background

Tumor cells benefit from their ability to avoid apoptosis and invade other tissues. The endoplasmic reticulum (ER) membrane protein Sec62 is a key player in these processes. Sec62 is essential for cell migration and protects tumor cells against thapsigargin-induced ER stress, which are both linked to cytosolic Ca²⁺. SEC62 silencing leads to elevated cytosolic Ca²⁺ and increased ER Ca²⁺ leakage after thapsigargin treatment. Sec62 protein levels are significantly increased in different tumors, including prostate, lung and thyroid cancer.

Methods

In lung cancer, the influence of Sec62 protein levels on patient survival was analyzed using the Kaplan-Meier method and log-rank test. To elucidate the underlying pathophysiological functions of Sec62, Ca²⁺ imaging techniques, real-time cell analysis and cell migration assays were performed. The effects of treatment with the calmodulin antagonists, trifluoperazine (TFP) and ophiobolin A, on cellular Ca²⁺ homeostasis, cell growth and cell migration were compared with the effects of siRNA-mediated Sec62 depletion or the expression of a mutated SEC62 variant in vitro. Using Biacore analysis we examined the Ca²⁺-sensitive interaction of Sec62 with the Sec61 complex.

Results

Sec62 overproduction significantly correlated with reduced patient survival. Therefore, Sec62 is not only a predictive marker for this type of tumor, but also an interesting therapeutic target. The present study suggests a regulatory function for Sec62 in the major Ca²⁺ leakage channel in the ER, Sec61, by a direct and Ca²⁺-sensitive interaction. A Ca²⁺-binding motif in Sec62 is essential for its molecular function. Treatment of cells with calmodulin antagonists mimicked Sec62 depletion by inhibiting cell migration and rendering the cells sensitive to thapsigargin treatment.

Conclusions

Targeting tumors that overproduce Sec62 with calmodulin antagonists in combination with targeted thapsigargin analogues may offer novel personalized therapeutic options.

The many faces of calmodulin in cell proliferation, programmed cell death, autophagy, and cancer

Calmodulin (CaM) is a ubiquitous Ca(2+) receptor protein mediating a large number of signaling processes in all eukaryotic cells. CaM plays a central role in regulating a myriad of cellular functions via interaction with multiple target proteins. This review focuses on the action of CaM and CaM-dependent signaling systems in the control of vertebrate cell proliferation, programmed cell death and autophagy. The significance of CaM and interconnected CaM-regulated systems for the physiology of cancer cells including tumor stem cells, and processes required for tumor progression such as growth, tumor-associated angiogenesis and metastasis are highlighted. Furthermore, the potential targeting of CaM-dependent signaling processes for therapeutic use is discussed.

Exploring the role of mitochondrial UQCRB in angiogenesis using small molecules

Bioactive small molecules are powerful tools used to evaluate protein function under physiological and pathological conditions. Over recent decades, utilization of a variety of biologically active small molecules in basic research and clinical applications has provided tremendous benefits in understanding the molecular mechanisms of biology and accelerating drug development. This review focuses on recent advances in the identification of new small molecules and their target proteins for exploring angiogenesis at the molecular level. In particular, we focus on the oxygen-sensing role of ubiquinol-cytochrome c reductase binding protein (UQCRB) of mitochondrial Complex III through identification of the protein target and the mode of action of a natural small molecule, terpestacin. The positive feedback approach of chemistry and biology provides a new way to explore functional roles of proteins and to translate this information into practical applications.

Suppression of experimental choroidal neovascularization by curcumin in mice

Purpose

To investigate the effects of curcumin on the development of experimental choroidal neovascularization (CNV) with underlying cellular and molecular mechanisms.

Methods

C57BL/6N mice were pretreated with intraperitoneal injections of curcumin daily for 3 days prior to laser-induced CNV, and the drug treatments were continued until the end of the study. The CNV area was analyzed by fluorescein-labeled dextran angiography of retinal pigment epithelium (RPE)-choroid flat mounts on day 7 and 14, and CNV leakage was evaluated by fluorescein angiography (FA) on day 14 after laser photocoagulation. The infiltration of F4/80 positive macrophages and GR-1 positive granulocytes were evaluated by immunohistochemistry on RPE-choroid flat mounts on day 3. Their expression in RPE-choroid complex was quantified by real-time PCR (F4/80) and Western blotting (GR-1) on day 3. RPE-choroid levels of vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1, and intercellular adhesion molecule (ICAM)-1 were examined by ELISA on day 3. Double immunostaining of F4/80 and VEGF was performed on cryo-sections of CNV lesions on day 3. The expression of nuclear factor (NF)-κB and hypoxia-inducible factor (HIF)−1α in the RPE-choroid was determined by Western blotting.

Results

Curcumin-treated mice had significantly less CNV area (P<0.05) and CNV leakage (P<0.001) than vehicle-treated mice. Curcumin treatment led to significant inhibition of F4/80 positive macrophages (P<0.05) and GR-1 positive granulocytes infiltration (P<0.05). VEGF mainly expressed in F4/80 positive macrophages in laser injury sites, which was suppressed by curcumin treatment (P<0.01). Curcumin inhibited the RPE-choroid levels of TNF-α (P<0.05), MCP-1 (P<0.05) and ICAM-1 (P<0.05), and suppressed the activation of NF-κB in nuclear extracts (P<0.05) and the activation of HIF−1α (P<0.05).

Conclusion

Curcumin treatment led to the suppression of CNV development together with inflammatory and angiogenic processes including NF-κB and HIF−1α activation, the up-regulation of inflammatory and angiogenic cytokines, and infiltrating macrophages and granulocytes. This provides molecular and cellular evidence of the validity of curcumin supplementation as a therapeutic strategy for the suppression of age-related macular degeneration (AMD)-associated CNV.

Vinorelbine inhibits angiogenesis and 95D migration via reducing hypoxic fibroblast stromal cell-derived factor 1 secretion

Tumor stroma plays a prominent role in cancer progression. Fibroblasts constitute a majority of the stromal cells in tumor, and yet the functional contributions of these cells to tumor angiogenesis and invasion are poorly understood, especially the anticancer drug interference to these processes. To estimate the effects of vinorelbine (VNR) on fibroblast-associated tumor invasion and angiogenesis, we evaluated the response of 95D and human umbilical vein endothelial cell (HUVEC) migration, tube formation in vitro, as well as capillary formation of rat thoracic aorta rings to hypoxic MRC-5 conditioned medium (CM) by VNR pretreatment. Our results demonstrated that VNR significantly inhibited 95D and HUVEC migration and angiogenesis induced by hypoxic MRC-5 cells. We also showed that hypoxic MRC-5 CM (Hypo-CM) had a higher level of stromal cell-derived factor 1 (SDF-1) secretion, while Hypo-CM up-regulated the CXCR4 expression in HUVECs and 95Ds. This increased activity of SDF-1/CXCR4 paracrine was clearly attenuated by VNR pretreatment. It was further found that pretreating HUVECs and 95Ds with AMD3100, a CXCR4 antagonist, markedly reversed the Hypo-CM promoting cell migration and angiogenesis, while adding exogenous SDF-1 attenuated the inhibition effects of CM collected from VNR-pretreated hypoxic MRC-5 (Hypo-CMV). These data indicate that VNR indirectly decreased 95D migration and angiogenesis through its effect on hypoxic MRC-5, via impacting SDF-1/CXCR4 paracrine, suggesting that VNR could interrupt the influence of fibroblasts on HUVECs and 95Ds to exert an anticancer role. Therefore, fibroblasts should be taken into consideration when evaluating and developing anticancer drugs.

Curcumin suppresses HIF1A synthesis and VEGFA release in pituitary adenomas

Curcumin (diferuloylmethane), a polyphenolic compound derived from the spice plant Curcuma longa, displays multiple actions on solid tumours including anti-angiogenic effects. Here we have studied in rodent and human pituitary tumour cells the influence of curcumin on the production of hypoxia inducible factor 1α (HIF1A) and vascular endothelial growth factor A (VEGFA), two key components involved in tumour neovascularisation through angiogenesis. Curcumin dose-dependently inhibited basal VEGFA secretion in corticotroph AtT20 mouse and lactosomatotroph GH3 rat pituitary tumour cells as well as in all human pituitary adenoma cell cultures (n=32) studied. Under hypoxia-mimicking conditions (CoCl(2) treatment) in AtT20 and GH3 cells as well as in all human pituitary adenoma cell cultures (n=8) studied, curcumin strongly suppressed the induction of mRNA synthesis and protein production of HIF1A, the regulated subunit of the hypoxia-induced transcription factor HIF1. Curcumin also blocked hypoxia-induced mRNA synthesis and secretion of VEGFA in GH3 cells and in all human pituitary adenoma cell cultures investigated (n=18). Thus, curcumin may inhibit pituitary adenoma progression not only through previously demonstrated anti-proliferative and pro-apoptotic actions but also by its suppressive effects on pituitary tumour neovascularisation.

The influence of genetic factors on the osteoinductive potential of calcium phosphate ceramics in mice

The efficacy of calcium phosphate (CaP) ceramics in healing large bone defects is, in general, not as high as that of autologous bone grafting. Recently, we reported that CaP ceramics with osteoinductive properties were as efficient in healing an ilium defect of a sheep as autologous bone graft was, which makes this subclass of CaP ceramics a powerful alternative for bone regeneration. Although osteoinduction by CaP ceramics has been shown in several large animal models it is sporadically reported in mice. Because the lack of a robust mouse model has delayed understanding of the mechanism, we screened mice from 11 different inbred mouse strains for their responsiveness to subcutaneous implantation of osteoinductive tricalcium phosphate (TCP). In only two strains (FVB and 129S2) the ceramic induced bone formation, and in particularly, in FVB mice, bone was found in all the tested mice. We also demonstrated that other CaP ceramics induced bone formation at the same magnitude as that observed in other animal models. Furthermore, VEGF did not significantly increase TCP induced bone formation. The mouse model here described can accelerate research of osteoinductive mechanisms triggered by CaP ceramics and potentially the development of therapies for bone regeneration.

Recent advances in hypoxia-inducible factor (HIF)-1 inhibitors

Tumor hypoxia has been recognized as a common feature of solid tumors and a negative prognostic factor for response to treatment and survival of cancer patients. The discovery of hypoxia-inducible factor-1 (HIF-1), a molecular determinant of responses to hypoxia in mammalian cells, has renewed enthusiasm for discovery and development of targeted therapies exploiting the hypoxic tumor microenvironment. HIF-1 activity in tumors depends on availability of the HIF-1α subunit, the levels of which increase under hypoxic conditions and through activation of oncogenes and/or inactivation of tumor suppressor genes. Increased HIF-1 has been correlated with increased angiogenesis, aggressive tumor growth, and poor patient prognosis, leading to current interest in HIF-1 as promising anticancer drug target. In spite of an ever increasing number of putative small molecule inhibitors of HIF-1, only a few are progressing through preclinical and early clinical development. In this review, we will discuss recent advances in discovery and development of small molecule inhibitors that target the HIF-1 pathway as potential anticancer agents.

Identification and biological activities of a new antiangiogenic small molecule that suppresses mitochondrial reactive oxygen species

Mitochondrial reactive oxygen species (ROS) are associated with multiple cellular functions such as cell proliferation, differentiation, and apoptosis. In particular, high levels of mitochondrial ROS in hypoxic cells regulate many angiogenesis-related diseases, including cancer and ischemic disorders. Here we report a new angiogenesis inhibitor, YCG063, which suppressed mitochondrial ROS generation in a phenotypic cell-based screening of a small molecule-focused library with an ArrayScan HCS reader. YCG063 suppressed mitochondrial ROS generation under a hypoxic condition in a dose-dependent manner, leading to the inhibition of in vitro angiogenic tube formation and chemoinvasion as well as in vivo angiogenesis of the chorioallantoic membrane (CAM) at non-toxic doses. In addition, YCG063 decreased the expression levels of HIF-1α and its target gene, VEGF. Collectively, a new antiangiogenic small molecule that suppresses mitochondrial ROS was identified. This new small molecule tool will provide a basis for a better understanding of angiogenesis driven under hypoxic conditions.