MicroRNA-195 inhibits colorectal cancer cell proliferation, colony-formation and invasion through targeting CARMA3

MicroRNA (miR)‑195 has been reported to be a tumor suppressor. Downregulation of miR‑195 has been shown to correlate with lymph node metastasis and poor prognosis in colorectal cancer. However, the specific regulatory role of miR‑195 in colorectal cancer cells is yet to be elucidated. In the present study, miR‑195 expression was significantly reduced in colorectal cancer tissues. Furthermore, CARMA3 was identified as a novel target of miR‑195, which was observed to be upregulated in colorectal cancer. In addition, downregulation of miR‑195 increased CARMA3 protein expression, whereas miR‑195 upregulation suppressed CARMA3 protein expression in SW480 and HT29 colorectal cancer cells. Moreover, overexpression of miR‑195 downregulated cell proliferation, colony‑formation and invasion in SW480 and HT29 cells, which was reversed upon CARMA3 overexpression. In conclusion, the findings of the present study suggest that miR‑195 has a suppressive role in colorectal cancer cells through directly targeting CARMA3. Therefore, CARMA3 may be a potential target for the treatment of colorectal cancer.

Sphingosine 1-phosphate: a potential molecular target for ovarian cancer therapy?

Sphingosine 1-phosphate (S1P) is an important signaling regulator involved in tumor progression in multiple neoplasms. However, the role of S1P in the pathogenesis of ovarian cancer remains unclear. Herein, we summarize recent advances in understanding the impact of S1P signaling in ovarian cancer progression. S1P, aberrantly produced in ovarian cancer patients, is involved in the regulation of key cellular processes that contribute to ovarian cancer initiation and progression. Moreover, agents that block the S1P signaling pathway inhibit ovarian cancer cell growth or induce apoptosis. Hence, current evidence suggests that S1P may become a potential molecular target for ovarian cancer therapy.

The clinically approved drugs amiodarone, dronedarone and verapamil inhibit filovirus cell entry

Objectives

Filoviruses such as Ebola virus and Marburg virus cause a severe haemorrhagic fever syndrome in humans for which there is no specific treatment. Since filoviruses use a complex route of cell entry that depends on numerous cellular factors, we hypothesized that there may be drugs already approved for human use for other indications that interfere with signal transduction or other cellular processes required for their entry and hence have anti-filoviral properties.

Methods

We used authentic filoviruses and lentiviral particles pseudotyped with filoviral glycoproteins to identify and characterize such compounds.

Results

We discovered that amiodarone, a multi-ion channel inhibitor and adrenoceptor antagonist, is a potent inhibitor of filovirus cell entry at concentrations that are routinely reached in human serum during anti-arrhythmic therapy. A similar effect was observed with the amiodarone-related agent dronedarone and the L-type calcium channel blocker verapamil. Inhibition by amiodarone was concentration dependent and similarly affected pseudoviruses as well as authentic filoviruses. Inhibition of filovirus entry was observed with most but not all cell types tested and was accentuated by the pre-treatment of cells, indicating a host cell-directed mechanism of action. The New World arenavirus Guanarito was also inhibited by amiodarone while the Old World arenavirus Lassa and members of the Rhabdoviridae (vesicular stomatitis virus) and Bunyaviridae (Hantaan) families were largely resistant.

Conclusions

The ion channel blockers amiodarone, dronedarone and verapamil inhibit filoviral cell entry.

One-electron oxidation reactions of purine and pyrimidine bases in cellular DNA

PURPOSE

The aim of this survey is to critically review the available information on one-electron oxidation reactions of nucleobases in cellular DNA with emphasis on damage induced through the transient generation of purine and pyrimidine radical cations. Since the indirect effect of ionizing radiation mediated by hydroxyl radical is predominant in cells, efforts have been made to selectively ionize bases using suitable one-electron oxidants that consist among others of high intensity UVC laser pulses. Thus, the main oxidation product in cellular DNA was found to be 8-oxo-7,8-dihydroguanine as a result of direct bi-photonic ionization of guanine bases and indirect formation of guanine radical cations through hole transfer reactions from other base radical cations. The formation of 8-oxo-7,8-dihydroguanine and other purine and pyrimidine degradation products was rationalized in terms of the initial generation of related radical cations followed by either hydration or deprotonation reactions in agreement with mechanistic pathways inferred from detailed mechanistic studies. The guanine radical cation has been shown to be implicated in three other nucleophilic additions that give rise to DNA-protein and DNA-DNA cross-links in model systems. Evidence was recently provided for the occurrence of these three reactions in cellular DNA.

CONCLUSION

There is growing evidence that one-electron oxidation reactions of nucleobases whose mechanisms have been characterized in model studies involving aqueous solutions take place in a similar way in cells. It may also be pointed out that the above cross-linked lesions are only produced from the guanine radical cation and may be considered as diagnostic products of the direct effect of ionizing radiation.

Vulvodynia and proctodynia treated with topical baclofen 5 % and palmitoylethanolamide

BACKGROUND

The prevalence of idiopathic vulvodynia and proctodynia is high. Pain management with anti-depressants and anti-epileptics may induce undesirable side effects. Therefore, topical baclofen cream and palmitoylethanolamide might be new therapeutic options.

CASE

A 33-year-old woman with intractable chronic vulvar and anal pain had to abstain from sexual intercourse and could neither cycle nor sit for more than 5 min. The patient did not respond to standard treatments. We prescribed a combination of topical baclofen 5 % and palmitoylethanolamide 400 mg, three times daily. After 3 months her symptoms decreased more than 50 % and sexual intercourse was possible again without pain.

CONCLUSION

Topical baclofen and palmitoylethanolamide can be a viable treatment option in chronic vulvodynia and proctodynia.

Danger signal adenosine via adenosine 2a receptor stimulates growth of Porphyromonas gingivalis in primary gingival epithelial cells

Extracellular signaling during inflammation and chronic diseases involves molecules referred to as 'Danger Signals' (DS), including the small molecule adenosine. We demonstrate that primary gingival epithelial cells (GEC) express a family of G-protein coupled receptors known as adenosine receptors, including the high-affinity receptors A1 and A2a and low-affinity receptors A2b and A3. Treatment of Porphyromonas gingivalis-infected GEC with the A2a receptor-specific agonist CGS-21680 resulted in elevated intracellular bacterial replication as determined by fluorescence microscopy and antibiotic protection assay. Additionally, A2a receptor antagonism and knockdown via RNA interference significantly reduced metabolically active intracellular P. gingivalis. Furthermore, analysis of anti-inflammatory mediator cyclic AMP (cAMP) following A2a receptor selective agonist CGS-21680 stimulation induced significantly higher levels of cAMP during P. gingivalis infection, indicating that adenosine signaling may attenuate inflammatory processes associated with bacterial infection. This study reveals that the GEC express functional A2a receptor and P. gingivalis may use the A2a receptor coupled DS adenosine signaling as a means to establish successful persistence in the oral mucosa, possibly via downregulation of the pro-inflammatory response.

mTOR enhances foam cell formation by suppressing the autophagy pathway

Recently, autophagy has drawn more attention in cardiovascular disease as it has important roles in lipid metabolism. Mammalian target of rapamycin (mTOR) is a key regulator of autophagy; however, its effect on atherosclerosis and the underlying mechanism remains undefined. In this study, an obvious upregulation of mTOR and p-mTOR protein was observed in macrophage-derived foam cells. Blocking mTOR expression with specific small interference RNA (siRNA) dramatically suppressed foam cell formation, accompanied by a decrease of lipid deposition. Further mechanistic analysis indicated that suppressing mTOR expression significantly upregulated autophagic marker LC3 expression and downregulated autophagy substrate p62 levels, indicating that mTOR silencing triggered autophagosome formation. Moreover, blocking mTOR expression obviously accelerated neutral lipid delivery to lysosome and cholesterol efflux from foam cells, implying that mTOR could induce macrophage foam cell formation by suppressing autophagic pathway. Further, mTOR silencing significantly upregulated ULK1 expression, which was accounted for mTOR-induced foam cell formation via autophagic pathway as treatment with ULK1 siRNA dampened LC3-II levels and increased p62 expression, concomitant with lipid accumulation and decreased cholesterol efflux from foam cells. Together, our data provide an insight into how mTOR accelerates the pathological process of atherosclerosis. Accordingly, blocking mTOR levels may be a promising therapeutic agent against atherosclerotic complications.

Emerging roles for lysophospholipid mediators in pregnancy

Recent progress in lipid research has unveiled new biologic roles for lysophospholipids as mediators of intercellular signaling. Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are representative lysophospholipids. Accumulating evidence suggests that, acting as intercellular mediators, these and other lysophospholipids may play important roles in physiological and pathological situations. This review discusses the possible involvement of LPA and S1P in reproductive processes, with a focus on the regulatory mechanisms of pregnancy maintenance. As LPA promotes prostaglandin synthesis, mediators in the LPA pathway may also play a significant role in implantation and parturition. S1P signaling is thought to be essential in vascular formation within the uteroplacental unit and in fetomaternal immunologic interactions. Derangements in either one of these lysophospholipid signaling pathways could result in pregnancy complications that may include implantation failure, preeclampsia, and preterm labor.

Transcription factor Ikaros represses protein phosphatase 2A (PP2A) expression through an intronic binding site

Protein phosphatase 2A (PP2A) is a highly conserved and ubiquitous serine/threonine phosphatase. We have shown previously that PP2A expression is increased in T cells of systemic lupus erythematosus patients and that this increased expression and activity of PP2A plays a central role in the molecular pathogenesis of systemic lupus erythematosus. Although the control of PP2A expression has been the focus of many studies, many aspects of its regulation still remain poorly understood. In this study, we describe a novel mechanism of PP2A regulation. We propose that the transcription factor Ikaros binds to a variant site in the first intron of PP2A and modulates its expression. Exogenous expression of Ikaros leads to reduced levels of PP2Ac message as well as protein. Conversely, siRNA-enabled silencing of Ikaros enhances the expression of PP2A, suggesting that Ikaros acts as a suppressor of PP2A expression. A ChIP analysis further proved that Ikaros is recruited to this site in T cells. We also attempted to delineate the mechanism of Ikaros-mediated PP2Ac gene suppression. We show that Ikaros-mediated suppression of PP2A expression is at least partially dependent on the recruitment of the histone deacetylase HDAC1 to this intronic site. We conclude that the transcription factor Ikaros can regulate the expression of PP2A by binding to a site in the first intron and modulating chromatin modifications at this site via recruitment of HDAC1.

Divergent signaling pathways cooperatively regulate TGFβ induction of cysteine-rich protein 2 in vascular smooth muscle cells

Background

Vascular smooth muscle cells (VSMCs) of the arterial wall play a critical role in the development of occlusive vascular diseases. Cysteine-rich protein 2 (CRP2) is a VSMC-expressed LIM-only protein, which functionally limits VSMC migration and protects against pathological vascular remodeling. The multifunctional cytokine TGFβ has been implicated to play a role in the pathogenesis of atherosclerosis through numerous downstream signaling pathways. We showed previously that TGFβ upregulates CRP2 expression; however, the detailed signaling mechanisms remain unclear.

Results

TGFβ treatment of VSMCs activated both Smad2/3 and ATF2 phosphorylation. Individually knocking down Smad2/3 or ATF2 pathways with siRNA impaired the TGFβ induction of CRP2, indicating that both contribute to CRP2 expression. Inhibiting TβRI kinase activity by SB431542 or TβRI knockdown abolished Smad2/3 phosphorylation but did not alter ATF2 phosphorylation, indicating while Smad2/3 phosphorylation was TβRI-dependent ATF2 phosphorylation was independent of TβRI. Inhibiting Src kinase activity by SU6656 suppressed TGFβ-induced RhoA and ATF2 activation but not Smad2 phosphorylation. Blocking ROCK activity, the major downstream target of RhoA, abolished ATF2 phosphorylation and CRP2 induction but not Smad2 phosphorylation. Furthermore, JNK inhibition with SP600125 reduced TGFβ-induced ATF2 (but not Smad2) phosphorylation and CRP2 protein expression while ROCK inhibition blocked JNK activation. These results indicate that downstream of TβRII, Src family kinase-RhoA-ROCK-JNK signaling pathway mediates TβRI-independent ATF2 activation. Promoter analysis revealed that the TGFβ induction of CRP2 was mediated through the CRE and SBE promoter elements that were located in close proximity.

Conclusions

Our results demonstrate that two signaling pathways downstream of TGFβ converge on the CRE and SBE sites of the Csrp2 promoter to cooperatively control CRP2 induction in VSMCs, which represents a previously unrecognized mechanism of VSMC gene induction by TGFβ.

Novel therapeutic targets in depression and anxiety: antioxidants as a candidate treatment

There is growing evidence that the imbalance between oxidative stress and the antioxidant defense system may be associated with the development neuropsychiatric disorders, such as depression and anxiety. Major depression and anxiety are presently correlated with a lowered total antioxidant state and by an activated oxidative stress (OS) pathway. The classical antidepressants may produce therapeutic effects other than regulation of monoamines by increasing the antioxidant levels and normalizing the damage caused by OS processes. This chapter provides an overview of recent work on oxidative stress markers in the animal models of depression and anxiety, as well as patients with the aforementioned mood disorders. It is well documented that antioxidants can remove the reactive oxygen species (ROS) and reactive nitrogen species (RNS) through scavenging radicals and suppressing the OS pathway, which further protect against neuronal damage caused oxidative or nitrosative stress sources in the brain, hopefully resulting in remission of depression or anxiety symptoms. The functional understanding of the relationship between oxidative stress and depression and anxiety may pave the way for discovery of novel targets for treatment of neuropsychiatric disorders.

Current concepts in pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia

The t(9;22)(q34;q11) or Philadelphia chromosome creates a BCR-ABL1 fusion gene encoding for a chimeric BCR-ABL1 protein. It is present in 3-4% of pediatric acute lymphoblastic leukemia (Ph(+) ALL), and about 25% of adult ALL cases. Prior to the advent of tyrosine kinase inhibitors (TKI), Ph(+) ALL was associated with a very poor prognosis despite the use of intensive chemotherapy and frequently hematopoietic stem-cell transplantation (HSCT) in first remission. The development of TKIs revolutionized the therapy of Ph(+) ALL. Addition of the first generation ABL1 class TKI imatinib to intensive chemotherapy dramatically increased the survival for children with Ph(+) ALL and established that many patients can be cured without HSCT. In parallel, the mechanistic understanding of Ph(+) ALL expanded exponentially through careful mapping of pathways downstream of BCR-ABL1, the discovery of mutations in master regulators of B-cell development such as IKZF1 (Ikaros), PAX5, and early B-cell factor (EBF), the recognition of the complex clonal architecture of Ph(+) ALL, and the delineation of genomic, epigenetic, and signaling abnormalities contributing to relapse and resistance. Still, many important basic and clinical questions remain unanswered. Current clinical trials are testing second generation TKIs in patients with newly diagnosed Ph(+) ALL. Neither the optimal duration of therapy nor the optimal chemotherapy backbone are currently defined. The role of HSCT in first remission and post-transplant TKI therapy also require further study. In addition, it will be crucial to continue to dig deeper into understanding Ph(+) ALL at a mechanistic level, and translate findings into complementary targeted approaches. Expanding targeted therapies hold great promise to decrease toxicity and improve survival in this high-risk disease, which provides a paradigm for how targeted therapies can be incorporated into treatment of other high-risk leukemias.

Matricellular proteins and biomaterials

Biomaterials are essential to modern medicine as components of reconstructive implants, implantable sensors, and vehicles for localized drug delivery. Advances in biomaterials have led to progression from simply making implants that are nontoxic to making implants that are specifically designed to elicit particular functions within the host. The interaction of implants and the extracellular matrix during the foreign body response is a growing area of concern for the field of biomaterials, because it can lead to implant failure. Expression of matricellular proteins is modulated during the foreign body response and these proteins interact with biomaterials. The design of biomaterials to specifically alter the levels of matricellular proteins surrounding implants provides a new avenue for the design and fabrication of biomimetic biomaterials.

Investigating molecular profiles of ovarian cancer: an update on cancer stem cells

Currently we are more and more improving our knowledge about the characteristics and the role of cancer stem cells in human cancer. Particularly we have realized that self-renewing ovarian cancer stem cells (CSCs) or ovarian cancer-initiating cells, and mesenchymal stem cells (SCs) too, are probably implicated in the etiopathogenesis of epithelial ovarian cancer (EOC). There is clear evidence that these cells are also involved in its intra- and extra-peritoneal diffusion and in the occurrence of chemo-resistance. In assessing the molecular characteristics of ovarian CSCs, we have to take note that these cellular populations are rare and the absence of specific cell surface markers represents a challenge to isolate and identify pure SC populations. In our review, we focused our attention on the molecular characteristics of epithelial ovarian CSCs and on the methods to detect them starting from their biological features. The study of ovarian CSCs is taking on an increasingly important strategic role, mostly for the potential therapeutic application in the next future.

Refining prognosis in BCR-ABL1-positive ALL

In this issue of Blood, van der Veer et al report the negative prognostic impact of IKZF1 deletions in children with BCR-ABL1–positive acute lymphoblastic leukemia (ALL), despite the use of tyrosine kinase inhibitor (TKI) therapy.1

Enhanced expression of Stim, Orai, and TRPC transcripts and proteins in endothelial progenitor cells isolated from patients with primary myelofibrosis

Background

An increase in the frequency of circulating endothelial colony forming cells (ECFCs), the only subset of endothelial progenitor cells (EPCs) truly belonging to the endothelial phenotype, occurs in patients affected by primary myelofibrosis (PMF). Herein, they might contribute to the enhanced neovascularisation of fibrotic bone marrow and spleen. Store-operated Ca²⁺ entry (SOCE) activated by the depletion of the inositol-1,4,5-trisphosphate (InsP₃)-sensitive Ca²⁺ store drives proliferation in ECFCs isolated from both healthy donors (N-ECFCs) and subjects suffering from renal cellular carcinoma (RCC-ECFCs). SOCE is up-regulated in RCC-ECFCs due to the over-expression of its underlying molecular components, namely Stim1, Orai1, and TRPC1.

Methodology/Principal Findings

We utilized Ca²⁺ imaging, real-time polymerase chain reaction, western blot analysis and functional assays to evaluate molecular structure and the functional role of SOCE in ECFCs derived from PMF patients (PMF-ECFCs). SOCE, induced by either pharmacological (i.e. cyclopiazonic acid or CPA) or physiological (i.e. ATP) stimulation, was significantly higher in PMF-ECFCs. ATP-induced SOCE was inhibited upon blockade of the phospholipase C/InsP₃ signalling pathway with U73111 and 2-APB. The higher amplitude of SOCE was associated to the over-expression of the transcripts encoding for Stim2, Orai2–3, and TRPC1. Conversely, immunoblotting revealed that Stim2 levels remained constant as compared to N-ECFCs, while Stim1, Orai1, Orai3, TRPC1 and TRPC4 proteins were over-expressed in PMF-ECFCs. ATP-induced SOCE was inhibited by BTP-2 and low micromolar La³⁺ and Gd³⁺, while CPA-elicited SOCE was insensitive to Gd³⁺. Finally, BTP-2 and La³⁺ weakly blocked PMF-ECFC proliferation, while Gd³⁺ was ineffective.

Conclusions

Two distinct signalling pathways mediate SOCE in PMF-ECFCs; one is activated by passive store depletion and is Gd³⁺-resistant, while the other one is regulated by the InsP₃-sensitive Ca²⁺ pool and is inhibited by Gd³⁺. Unlike N- and RCC-ECFCs, the InsP₃-dependent SOCE does not drive PMF-ECFC proliferation.

The neurobiological pathogenesis of poststroke depression

Poststroke depression (PSD) is an important consequence after stroke, with negative impact on stroke outcome. The pathogenesis of PSD is complicated, with some special neurobiological mechanism, which mainly involves neuroanatomical, neuron, and biochemical factors and neurogenesis which interact in complex ways. Abundant studies suggested that large lesions in critical areas such as left frontal lobe and basal ganglia or accumulation of silent cerebral lesions might interrupt the pathways of monoamines or relevant pathways of mood control, thus leading to depression. Activation of immune system after stroke produces more cytokines which increase glutamate excitotoxicity, results in more cell deaths of critical areas and enlargement of infarctions, and, together with hypercortisolism induced by stress or inflammation after stroke which could decrease intracellular serotonin transporters, might be the key biochemical change of PSD. The interaction among cytokines, glucocorticoid, and neurotrophin results in the decrease of hippocampal neurogenesis which has been proved to be important for mood control and pharmaceutical effect of selective serotonin reuptake inhibitors and might be another promising pathway to understand the pathogenesis of PSD. In order to reduce the prevalence of PSD and improve the outcome of stroke, more relevant studies are still required to clarify the pathogenesis of PSD.

Role of κ→λ light-chain constant-domain switch in the structure and functionality of A17 reactibody

The engineering of catalytic function in antibodies requires precise information on their structure. Here, results are presented that show how the antibody domain structure affects its functionality. The previously designed organophosphate-metabolizing reactibody A17 has been re-engineered by replacing its constant κ light chain by the λ chain (A17λ), and the X-ray structure of A17λ has been determined at 1.95 Å resolution. It was found that compared with A17κ the active centre of A17λ is displaced, stabilized and made more rigid owing to interdomain interactions involving the CDR loops from the VL and VH domains. These VL/VH domains also have lower mobility, as deduced from the atomic displacement parameters of the crystal structure. The antibody elbow angle is decreased to 126° compared with 138° in A17κ. These structural differences account for the subtle changes in catalytic efficiency and thermodynamic parameters determined with two organophosphate ligands, as well as in the affinity for peptide substrates selected from a combinatorial cyclic peptide library, between the A17κ and A17λ variants. The data presented will be of interest and relevance to researchers dealing with the design of antibodies with tailor-made functions.

Molecular and cellular mechanisms underlying anti-neuronal antibody mediated disorders of the central nervous system

Over the last decade multiple autoantigens located on the plasma membrane of neurons have been identified. Neuronal surface antigens include molecules directly involved in neurotransmission and excitability. Binding of the antibody to the antigen may directly alter the target protein's function, resulting in neurological disorders. The often striking reversibility of symptoms following early aggressive immunotherapy supports a pathogenic role for autoantibodies to neuronal surface antigens. In order to better understand and treat these neurologic disorders it is important to gain insight in the underlying mechanisms of antibody pathogenicity. In this review we discuss the clinical, circumstantial, in vitro and in vivo evidence for neuronal surface antibody pathogenicity and the possible underlying cellular and molecular mechanisms. This review shows that antibodies to neuronal surface antigens are often directed at conformational epitopes located in the extracellular domain of the antigen. The conformation of the epitope can be affected by specific posttranslational modifications. This may explain the distinct clinical phenotypes that are seen in patients with antibodies to antigens that are expressed throughout the brain. Furthermore, it is likely that there is a heterogeneous antibody population, consisting of different IgG subtypes and directed at multiple epitopes located in an immunogenic region. Binding of these antibodies may result in different pathophysiological mechanisms occurring in the same patient, together contributing to the clinical syndrome. Unraveling the predominant mechanism in each distinct antigen could provide clues for therapeutic interventions.

Altered miRNA expression in canine retinas during normal development and in models of retinal degeneration

Background

Although more than 246 loci/genes are associated with inherited retinal diseases, the mechanistic events that link genetic mutations to photoreceptor cell death are poorly understood. miRNAs play a relevant role during retinal development and disease. Thus, as a first step in characterizing miRNA involvement during disease expression and progression, we examined miRNAs expression changes in normal retinal development and in four canine models of retinal degenerative disease.

Results

The initial microarray analysis showed that 50 miRNAs were differentially expressed (DE) early (3 vs. 7 wks) in normal retina development, while only 2 were DE between 7 and 16 wks, when the dog retina is fully mature. miRNA expression profiles were similar between dogs affected with xlpra2, an early-onset retinal disease caused by a microdeletion in RPGRORF15, and normal dogs early in development (3 wks) and at the peak of photoreceptor death (7 wks), when only 2 miRNAs were DE. However, the expression varied much more markedly during the chronic cell death stage at 16 wks (118 up-/55 down-regulated miRNAs). Functional analyses indicated that these DE miRNAs are associated with an increased inflammatory response, as well as cell death/survival. qRT-PCR of selected apoptosis-related miRNAs (“apoptomirs”) confirmed the microarray results in xlpra2, and extended the analysis to the early-onset retinal diseases rcd1 (PDE6B-mutation) and erd (STK38L-mutation), as well as the slowly progressing prcd (PRCD-mutation). The results showed up-regulation of anti-apoptotic (miR-9, -19a, -20, -21, -29b, -146a, -155, -221) and down-regulation of pro-apoptotic (miR-122, -129) apoptomirs in the early-onset diseases and, with few exceptions, also in the prcd-mutants.

Conclusions

Our results suggest that apoptomirs might be expressed by diseased retinas in an attempt to counteract the degenerative process. The pattern of expression in diseased retinas mirrored the morphology and cell death kinetics previously described for these diseases. This study suggests that common miRNA regulatory mechanisms may be involved in retinal degeneration processes and provides attractive opportunities for the development of novel miRNA-based therapies to delay the progression of the degenerative process.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-172) contains supplementary material, which is available to authorized users.

Dual inhibition of phosphatidylinositol 3'-kinase and mammalian target of rapamycin using NVP-BEZ235 as a novel therapeutic approach for mucinous adenocarcinoma of the ovary

Ovarian mucinous adenocarcinoma (MAC) resists standard chemotherapy and is associated with poor prognosis. A more effective treatment is needed urgently. The present study assessed the possibility of molecular-targeted therapy with a novel dual inhibitor of phosphatidylinositol 3'-kinase (PI3K) and mammalian target of rapamycin (mTOR), NVP-BEZ235 (BEZ235) to treat of MAC. Seven human MAC cell lines were used in this study. The sensitivity of the cells to BEZ235, temsirolimus, and anticancer agents was determined with the WST-8 assay. Cell cycle distribution was assessed by flow cytometry, and the expression of proteins in apoptotic pathways and molecules of the PI3K/Akt/mTOR signaling pathways was determined by Western blot analysis. We also examined the effects of BEZ235 on tumor growth in nude mice xenograft models. The cell lines showed half-maximal inhibitory concentration values of BEZ235 from 13 to 328 nmol/L. Low half-maximal inhibitory concentration values to BEZ235 were observed in MCAS and OMC-1 cells; these 2 lines have an activating mutation in the PIK3CA gene. NVP-BEZ235 down-regulated the protein expression of phosphorylated (p-) Akt, p-p70S6K, and p-4E-BP1, suppressed cell cycle progression, up-regulated the expression of cleaved PARP and cleaved caspase 9, and increased apoptotic cells. Synergistic effects were observed on more than 5 cell lines when BEZ235 was combined with paclitaxel or cisplatin. The treatment of mice bearing OMC-1 or RMUG-S with BEZ235 significantly suppressed tumor growth in MAC xenograft models without severe weight loss. We conclude that the PI3K/Akt/mTOR pathway is a potential therapeutic target and that BEZ235 should be explored as a therapeutic agent for MAC.

An eEF1A1 truncation encoded by PTI-1 exerts its oncogenic effect inside the nucleus

Background

The oncogene PTI-1 was originally isolated from a prostate cancer cell line by its capability to transform rat fibroblasts. The PTI-1 mRNA has a very eccentric structure as the 5′UTR is similar to prokaryotic 23S rRNA, while the major open reading frame and the 3′UTR corresponds to a part of the mRNA encoding human translation elongation factor eEF1A1. Thus, the largest open reading frame encodes a truncated version of eEF1A1 lacking the first 67 amino acids, while having three unique N-terminal amino acids. Previously, the UTRs were shown to be a prerequisite for the transforming capacity of the PTI-1 transcript. In this study, we have investigated the possible role of the UTRs in regulating protein expression and localization.

Methods

The protein expression profiles of a number of PTI-1 mRNA variants were studied in vitro and in vivo. Furthermore, the oncogenic potentials of the same PTI-1 mRNAs were determined by monitoring the capacities of stably transfected cells expressing these mRNAs to induce tumors in nude mice and form foci in cell culture. Finally, the cellular localizations of PTI-1 proteins expressed from these mRNAs were determined by fluorescence microscopy.

Results

The PTI-1 mRNA was found to give rise to multiple protein products that potentially originate from translation initiation at downstream, inframe AUGs within the major open reading frame. At least one of the truncated protein variants was also found to be oncogenic. However, the UTRs did not appear to influence the amount and identities of these truncated protein products. In contrast, our localization studies showed that the UTRs of the transcript promote a nuclear localization of the encoded protein(s).

Conclusions

Translation of the PTI-1 mRNA results in multiple protein products of which (a) truncated variant(s) may play a predominant role during cellular transformation. The PTI-1 UTRs did not seem to play a role in translation regulation, but appeared to contribute to a nuclear localization of the PTI-1 protein(s). This indicates that the PTI-1 protein(s) exert(s) its/their oncogenic function inside the nucleus.

MicroRNA dysregulation in spinal cord injury: causes, consequences and therapeutics

Trauma to the spinal cord causes permanent disability to more than 180,000 people every year worldwide. The initial mechanical damage triggers a complex set of secondary events involving the neural, vascular, and immune systems that largely determine the functional outcome of the spinal cord injury (SCI). Cellular and biochemical mechanisms responsible for this secondary injury largely depend on activation and inactivation of specific gene programs. Recent studies indicate that microRNAs function as gene expression switches in key processes of the SCI. Microarray data from rodent contusion models reveal that SCI induces changes in the global microRNA expression patterns. Variations in microRNA abundance largely result from alterations in the expression of the cells at the damaged spinal cord. However, microRNA expression levels after SCI are also influenced by the infiltration of immune cells to the injury site and the death and migration of specific neural cells after injury. Evidences on the role of microRNAs in the SCI pathophysiology have come from different sources. Bioinformatic analysis of microarray data has been used to identify specific variations in microRNA expression underlying transcriptional changes in target genes, which are involved in key processes in the SCI. Direct evidences on the role of microRNAs in SCI are scarcer, although recent studies have identified several microRNAs (miR-21, miR-486, miR-20) involved in key mechanisms of the SCI such as cell death or astrogliosis, among others. From a clinical perspective, different evidences make clear that microRNAs can be potent therapeutic tools to manipulate cell state and molecular processes in order to enhance functional recovery. The present article reviews the actual knowledge on how injury affects microRNA expression and the meaning of these changes in the SCI pathophysiology, to finally explore the clinical potential of microRNAs in the SCI.

The plasma membrane calcium pump: new ways to look at an old enzyme

The three-dimensional structure of the PMCA pump has not been solved, but its basic mechanistic properties are known to repeat those of the other Ca(2+) pumps. However, the pump also has unique properties. They concern essentially its numerous regulatory mechanisms, the most important of which is the autoinhibition by its C-terminal tail. Other regulatory mechanisms involve protein kinases and the phospholipids of the membrane in which the pump is embedded. Permanent activation of the pump, e.g. by calmodulin, is physiologically as harmful to cells as its absence. The concept is now emerging that the global control of cell Ca(2+) may not be the main function of the pump; in some cell types, it could even be irrelevant. The main pump role would be the regulation of Ca(2+) in cell microdomains in which the pump co-segregates with partners that modulate the Ca(2+) message and transduce it to important cell functions.

High-density lipoprotein cholesterol raising: does it matter?

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is the leading cause of morbidity and premature mortality in Europe and the United States, and is increasingly common in developing countries. High-density lipoprotein cholesterol (HDL-C) is an independent risk factor for CVD and is superior to low-density lipoprotein cholesterol (LDL-C) as a predictor of cardiovascular events. The residual risk conferred by low HDL-C in patients with a satisfactory LDL-C was recently highlighted by the European Atherosclerosis Society. Despite the lack of randomized controlled trials, it has been suggested that raising the level of HDL-C should be considered as a therapeutic strategy in high-risk patients because of the strong epidemiological evidence, compelling biological plausibility, and both experimental and clinical research supporting its cardioprotective effects.

RECENT FINDINGS

Three recent large randomized clinical trials investigating the effect of HDL-C raising with niacin and dalcetrapib in statin-treated patients failed to demonstrate an improvement in cardiovascular outcomes.

SUMMARY

There is evidence to support the view that HDL functionality and the mechanism by which a therapeutic agent raises HDL-C are more important than plasma HDL-C levels. Future therapeutic agents will be required to improve this functionality rather than simply raising the cholesterol cargo.

Aspartic peptidases of human pathogenic trypanosomatids: perspectives and trends for chemotherapy

Aspartic peptidases are proteolytic enzymes present in many organisms like vertebrates, plants, fungi, protozoa and in some retroviruses such as human immunodeficiency virus (HIV). These enzymes are involved in important metabolic processes in microorganisms/virus and play major roles in infectious diseases. Although few studies have been performed in order to identify and characterize aspartic peptidase in trypanosomatids, which include the etiologic agents of leishmaniasis, Chagas’ disease and sleeping sickness, some beneficial properties of aspartic peptidase inhibitors have been described on fundamental biological events of these pathogenic agents. In this context, aspartic peptidase inhibitors (PIs) used in the current chemotherapy against HIV (e.g., amprenavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir) were able to inhibit the aspartic peptidase activity produced by different species of Leishmania. Moreover, the treatment of Leishmania promastigotes with HIV PIs induced several perturbations on the parasite homeostasis, including loss of the motility and arrest of proliferation/growth. The HIV PIs also induced an increase in the level of reactive oxygen species and the appearance of irreversible morphological alterations, triggering parasite death pathways such as programed cell death (apoptosis) and uncontrolled autophagy. The blockage of physiological parasite events as well as the induction of death pathways culminated in its incapacity to adhere, survive and escape of phagocytic cells. Collectively, these results support the data showing that parasites treated with HIV PIs have a significant reduction in the ability to cause in vivo infection. Similarly, the treatment of Trypanosoma cruzi cells with pepstatin A showed a significant inhibition on both aspartic peptidase activity and growth as well as promoted several and irreversible morphological changes. These studies indicate that aspartic peptidases can be promising targets in trypanosomatid cells and aspartic proteolytic inhibitors can be benefic chemotherapeutic agents against these human pathogenic microorganisms.

p53: the barrier to cancer stem cell formation

The role of p53 as the "guardian of the genome" in differentiated somatic cells, triggering various biological processes, is well established. Recent studies in the stem cell field have highlighted a profound role of p53 in stem cell biology as well. These studies, combined with basic data obtained 20 years ago, provide insight into how p53 governs the quantity and quality of various stem cells, ensuring a sufficient repertoire of normal stem cells to enable proper development, tissue regeneration and a cancer free life. In this review we address the role of p53 in genomically stable embryonic stem cells, a unique predisposed cancer stem cell model and adult stem cells, its role in the generation of induced pluripotent stem cells, as well as its role as the barrier to cancer stem cell formation.

miR-138 inhibits proliferation by targeting 3-phosphoinositide-dependent protein kinase-1 in non-small cell lung cancer cells

OBJECTIVE

Underlying mechanisms of non-small cell lung cancer (NSCLC) development remain poorly understood. miR-138 and 3-phosphoinositide-dependent protein kinase-1 (PDK1) have been reported to be involved in the genesis of NSCLC. The aim of this study was to investigate the role and mechanisms of miR-138 and PDK1 in human NSCLC cells.

METHODS

The effect of miR-138 on proliferation of A549 lung cancer cells was first examined using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. The expression of PDK1 in A549 lung cancer cells was assessed by real-time polymerase chain reaction further. A luciferase reporter activity assay was conducted to confirm target association between miR-138 and 3' untranslated region (3'-UTR) of PDK1. Finally, the role of PDK1 on proliferation of A549 cells was evaluated by transefection of PDK1 small interfering RNA (siRNA).

RESULTS

Proliferation of A549 lung cancer cells was suppressed by miR-138 in a concentration-dependent manner. Furthermore, miR-138 can bind to the 3'-UTR of PDK1 and downregulate expression of PDK1 at both mRNA and protein levels. Knockdown of PDK1 by siRNA significantly inhibits the proliferation of A549 lung cancer cells.

CONCLUSIONS

These findings suggest that miR-138 as a potential tumor suppressor could inhibit cell proliferation by targeting PDK1 in NSCLC cells, which could be employed as a potential therapeutic target for miRNA-based NSCLC therapy.

The MOC31PE immunotoxin reduces cell migration and induces gene expression and cell death in ovarian cancer cells

Background

The standard treatment of ovarian cancer with chemotherapy often leads to drug resistance and relapse of the disease, and the need for development of novel therapy alternatives is obvious. The MOC31PE immunotoxin binds to the cell surface antigen EpCAM, which is expressed by the majority of epithelial cancers including ovarian carcinomas, and we studied the cytotoxic effects of MOC31PE in ovarian cancer cells.

Methods

Investigation of the effects of MOC31PE treatment on protein synthesis, cell viability, proliferation and gene expression of the ovarian cancer cell lines B76 and HOC7.

Results

MOC31PE treatment for 24 h caused a dose-dependent reduction of protein synthesis with ID₅₀ values of less than 10 ng/ml, followed by reduced cell viability. In a gene expression array monitoring the expression of 84 key genes in cancer pathways, 13 of the genes were differentially expressed by MOC31PE treatment in comparison to untreated cells. By combining MOC31PE and the immune suppressor cyclosporin A (CsA) the MOC31PE effect on protein synthesis inhibition and cell viability increased tenfold. Cell migration was also reduced, both in the individual MOC31PE and CsA treatment, but even more when combining MOC31PE and CsA. In tumor metastasis PCR arrays, 23 of 84 genes were differentially expressed comparing CsA versus MOC31PE + CsA treatment. Increased expression of the tumor suppressor KISS1 and the nuclear receptor NR4A3 was observed, and the differential candidate gene expression was confirmed in complementary qPCR analyses. For NR4A3 this was not accompanied by increased protein expression. However, a subcellular fractionation assay revealed increased mitochondrial NR4A3 in MOC31PE treated cells, suggesting a role for this protein in MOC31PE-induced apoptotic cell death.

Conclusion

The present study demonstrates that MOC31PE may become a new targeted therapy for ovarian cancer and that the MOC31PE anti-cancer effect is potentiated by CsA.

Site-specific functionalization of proteins and their applications to therapeutic antibodies

Protein modifications are often required to study structure and function relationships. Instead of the random labeling of lysine residues, methods have been developed to (sequence) specific label proteins. Next to chemical modifications, tools to integrate new chemical groups for bioorthogonal reactions have been applied. Alternatively, proteins can also be selectively modified by enzymes. Herein we review the methods available for site-specific modification of proteins and their applications for therapeutic antibodies.

Distinct regions of triadin are required for targeting and retention at the junctional domain of the sarcoplasmic reticulum

Three regions contribute to triadin localization to the junctional sarcoplasmic reticulum. Dynamics studies revealed that TR3 mediates triadin stability at junctional sites. The stable association of triadin at the junctional sites is facilitated by interactions with calsequestrin-1.

Modelling effects of internalized antibody: a simple comparative study

BACKGROUND

The modelling framework is proposed to study protection properties of antibodies to neutralize the effects of the plant toxin (ricin). The present study extends our previous work by including (i) the model of intracellular transport of toxin to the Endoplasmic Reticulum and (ii) the model of the internalised antibodies (when antibody is delivered directly into the cytosol).

METHOD

Simulation of the receptor-toxin-antibody interaction is implemented by solving the systems of PDEs (advection-diffusion models) or ODEs (rate models) for the underlying transport coupled with mass-action kinetics.

RESULTS

As the main application of the enhanced framework we present a comparative study of two kinds (external and internalised) of antibodies. This comparison is based on calculation of the non-dimensional protection factor using the same set of parameters (geometry, binding constants, initial concentrations of species, and total initial amount of the antibody).

CONCLUSION

This research will provide a framework for consistent evaluation and comparison of different types of antibodies for toxicological applications.

Vascular smooth muscle cell-derived transforming growth factor-β promotes maturation of activated, neointima lesion-like macrophages

OBJECTIVE

To define the contribution of vascular smooth muscle cell (SMC)-derived factors to macrophage phenotypic modulation in the setting of vascular injury.

APPROACH AND RESULTS

By flow cytometry, macrophages (M4) were the predominant myeloid cell type recruited to wire-injured femoral arteries, in mouse, compared with neutrophils or eosinophils. Recruited macrophages from injured vessels exhibited a distinct expression profile relative to circulating mononuclear cells (peripheral blood monocytes; increased: interleukin-6, interleukin-10, interleukin-12b, CC chemokine receptor [CCR]3, CCR7, tumor necrosis factor-α, inducible nitric oxide synthase, arginase 1; decreased: interleukin-12a, matrix metalloproteinase [MMP]9). This phenotype was recapitulated in vitro by maturing rat bone marrow cells in the presence of macrophage-colony stimulating factor and 20% conditioned media from cultured rat SMC (sMϕ) compared with maturation in macrophage-colony stimulating factor alone (M0). Recombinant transforming growth factor (TGF)-β1 recapitulated the effect of SMC conditioned media. Macrophage maturation studies performed in the presence of a pan-TGF-β neutralizing antibody, a TGF-β receptor inhibitor, or conditioned media from TGF-β-depleted SMCs confirmed that the SMC-derived factor responsible for macrophage activation was TGF-β. Finally, the effect of SMC-mediated macrophage activation on SMC biology was assessed. SMCs cocultured with sMϕ exhibited increased rates of proliferation relative to SMCs cultured alone or with M0 macrophages.

CONCLUSIONS

SMC-derived TGF-β modulates the phenotype of maturing macrophages in vitro, recapitulating the phenotype found in vascular lesions in vivo. SMC-modulated macrophages induce SMC activation to a greater extent than control macrophages.

Nanoparticles in relation to peptide and protein aggregation

Over the past two decades, there has been considerable research interest in the use of nanoparticles in the study of protein and peptide aggregation, and of amyloid-related diseases. The influence of nanoparticles on amyloid formation yields great interest due to its small size and high surface area-to-volume ratio. Targeting nucleation kinetics by nanoparticles is one of the most searched for ways to control or induce this phenomenon. The observed effect of nanoparticles on the nucleation phase is determined by particle composition, as well as the amount and nature of the particle's surface. Various thermodynamic parameters influence the interaction of proteins and nanoparticles in the solution, and regulate the protein assembly into fibrils, as well as the disaggregation of preformed fibrils. Metals, organic particles, inorganic particles, amino acids, peptides, proteins, and so on are more suitable candidates for nanoparticle formulation. In the present review, we attempt to explore the effects of nanoparticles on protein and peptide fibrillation processes from both perspectives (ie, as inducers and inhibitors on nucleation kinetics and in the disaggregation of preformed fibrils). Their formulation and characterization by different techniques have been also addressed, along with their toxicological effects, both in vivo and in vitro.

Epstein-Barr virus utilizes Ikaros in regulating its latent-lytic switch in B cells

Ikaros is a zinc finger DNA-binding protein that regulates chromatin remodeling and the expression of genes involved in the cell cycle, apoptosis, and Notch signaling. It is a master regulator of lymphocyte differentiation and functions as a tumor suppressor in acute lymphoblastic leukemia. Nevertheless, no previous reports described effects of Ikaros on the life cycle of any human lymphotropic virus. Here, we demonstrate that full-length Ikaros (IK-1) functions as a major factor in the maintenance of viral latency in Epstein-Barr virus (EBV)-positive Burkitt's lymphoma Sal and MutuI cell lines. Either silencing of Ikaros expression by small hairpin RNA (shRNA) knockdown or ectopic expression of a non-DNA-binding isoform induced lytic gene expression. These effects synergized with other lytic inducers of EBV, including transforming growth factor β (TGF-β) and the hypoxia mimic desferrioxamine. Data from chromatin immunoprecipitation (ChIP)-quantitative PCR (qPCR) and ChIP-sequencing (ChIP-seq) analyses indicated that Ikaros did not bind to either of the EBV immediate early genes BZLF1 and BRLF1. Rather, Ikaros affected the expression of Oct-2 and Bcl-6, other transcription factors that directly inhibit EBV reactivation and plasma cell differentiation, respectively. IK-1 also complexed with the EBV immediate early R protein in coimmunoprecipitation assays and partially colocalized with R within cells. The presence of R alleviated IK-1-mediated transcriptional repression, with IK-1 then cooperating with Z and R to enhance lytic gene expression. Thus, we conclude that Ikaros plays distinct roles at different stages of EBV's life cycle: it contributes to maintaining latency via indirect mechanisms, and it may also synergize with Z and R to enhance lytic replication through direct association with R and/or R-induced alterations in Ikaros' functional activities via cellular signaling pathways.

IMPORTANCE

This is the first report showing that the cellular protein Ikaros, a known master regulator of hematopoiesis and critical tumor suppressor in acute lymphoblastic leukemia, also plays important roles in the life cycle of Epstein-Barr virus in B cells.

Silencing of Atp2b1 increases blood pressure through vasoconstriction

BACKGROUND

Recent genome-wide association studies (GWASs) have identified 30 genetic loci that regulate blood pressure, increasing our understanding of the cause of hypertension. However, it has been difficult to define the causative genes at these loci due to a lack of functional analyses.

METHOD

In this study, we aimed to validate the candidate gene ATP2B1 in 12q21, variants near which have the strongest association with blood pressure in Asians and Europeans. ATP2B1 functions as a calcium pump to fine-tune calcium concentrations - necessary for repolarization following muscular contractions. We silenced Atp2b1 using an siRNA complex, injected into mouse tail veins.

RESULTS

In treated mice, blood pressure rose and the mesenteric arteries increased in wall : lumen ratio. Moreover, the arteries showed enhanced myogenic responses to pressure, and contractile responses to phenylephrine increased compared with the control, suggesting that blood pressure is regulated by ATP2B1 through the contraction and dilation of the vessel, likely by controlling calcium concentrations in the resting state.

CONCLUSION

These results support that ATP2B1 is the causative gene in the blood pressure-associated 12q21 locus and demonstrate that ATP2B1 expression in the vessel influences blood pressure.

Monoclonal antibody disposition: a simplified PBPK model and its implications for the derivation and interpretation of classical compartment models

The structure, interpretation and parameterization of classical compartment models as well as physiologically-based pharmacokinetic (PBPK) models for monoclonal antibody (mAb) disposition are very diverse, with no apparent consensus. In addition, there is a remarkable discrepancy between the simplicity of experimental plasma and tissue profiles and the complexity of published PBPK models. We present a simplified PBPK model based on an extravasation rate-limited tissue model with elimination potentially occurring from various tissues and plasma. Based on model reduction (lumping), we derive several classical compartment model structures that are consistent with the simplified PBPK model and experimental data. We show that a common interpretation of classical two-compartment models for mAb disposition-identifying the central compartment with the total plasma volume and the peripheral compartment with the interstitial space (or part of it)-is not consistent with current knowledge. Results are illustrated for the monoclonal antibodies 7E3 and T84.66 in mice.

Remodelling of Ca2+ transport in cancer: how it contributes to cancer hallmarks?

Cancer involves defects in the mechanisms underlying cell proliferation, death and migration. Calcium ions are central to these phenomena, serving as major signalling agents with spatial localization, magnitude and temporal characteristics of calcium signals ultimately determining cell's fate. Cellular Ca(2+) signalling is determined by the concerted action of a molecular Ca(2+)-handling toolkit which includes: active energy-dependent Ca(2+) transporters, Ca(2+)-permeable ion channels, Ca(2+)-binding and storage proteins, Ca(2+)-dependent effectors. In cancer, because of mutations, aberrant expression, regulation and/or subcellular targeting of Ca(2+)-handling/transport protein(s) normal relationships among extracellular, cytosolic, endoplasmic reticulum and mitochondrial Ca(2+) concentrations or spatio-temporal patterns of Ca(2+) signalling become distorted. This causes deregulation of Ca(2+)-dependent effectors that control signalling pathways determining cell's behaviour in a way to promote pathophysiological cancer hallmarks such as enhanced proliferation, survival and invasion. Despite the progress in our understanding of Ca(2+) homeostasis remodelling in cancer cells as well as in identification of the key Ca(2+)-transport molecules promoting certain malignant phenotypes, there is still a lot of work to be done to transform fundamental findings and concepts into new Ca(2+) transport-targeting tools for cancer diagnosis and treatment.

Fatostatin displays high antitumor activity in prostate cancer by blocking SREBP-regulated metabolic pathways and androgen receptor signaling

Current research links aberrant lipogenesis and cholesterogenesis with prostate cancer development and progression. Sterol regulatory element-binding proteins (SREBP; SREBP-1 and SREBP-2) are key transcription factors controlling lipogenesis and cholesterogenesis via the regulation of genes related to fatty acid and cholesterol biosynthesis. Overexpression of SREBPs has been reported to be significantly associated with aggressive pathologic features in human prostate cancer. Our previous results showed that SREBP-1 promoted prostate cancer growth and castration resistance through induction of lipogenesis and androgen receptor (AR) activity. In the present study, we evaluated the anti-prostate tumor activity of a novel SREBP inhibitor, fatostatin. We found that fatostatin suppressed cell proliferation and anchorage-independent colony formation in both androgen-responsive LNCaP and androgen-insensitive C4-2B prostate cancer cells. Fatostatin also reduced in vitro invasion and migration in both the cell lines. Further, fatostatin caused G2-M cell-cycle arrest and induced apoptosis by increasing caspase-3/7 activity and the cleavages of caspase-3 and PARP. The in vivo animal results demonstrated that fatostatin significantly inhibited subcutaneous C4-2B tumor growth and markedly decreased serum prostate-specific antigen (PSA) level compared with the control group. The in vitro and in vivo effects of fatostatin treatment were due to blockade of SREBP-regulated metabolic pathways and the AR signaling network. Our findings identify SREBP inhibition as a potential new therapeutic approach for the treatment of prostate cancer.

Thioredoxin-interacting protein is required for endothelial NLRP3 inflammasome activation and cell death in a rat model of high-fat diet

AIMS/HYPOTHESIS

Obesity and hypertension, known pro-inflammatory states, are identified determinants for increased retinal microvascular abnormalities. However, the molecular link between inflammation and microvascular degeneration remains elusive. Thioredoxin-interacting protein (TXNIP) is recognised as an activator of the NOD-like receptor pyrin domain containing-3 (NLRP3) inflammasome. This study aims to examine TXNIP expression and elucidate its role in endothelial inflammasome activation and retinal lesions.

METHODS

Spontaneously hypertensive (SHR) and control Wistar (W) rats were compared with groups fed a high-fat diet (HFD) (W+F and SHR+F) for 8-10 weeks.

RESULTS

Compared with W controls, HFD alone or in combination with hypertension significantly induced formation of acellular capillaries, a hallmark of retinal ischaemic lesions. These effects were accompanied by significant increases in lipid peroxidation, nitrotyrosine and expression of TXNIP, nuclear factor κB, TNF-α and IL-1β. HFD significantly increased interaction of TXNIP-NLRP3 and expression of cleaved caspase-1 and cleaved IL-1β. Immunolocalisation studies identified TXNIP expression within astrocytes and Müller cells surrounding retinal endothelial cells. To model HFD in vitro, human retinal endothelial (HRE) cells were stimulated with 400 μmol/l palmitate coupled to BSA (Pal-BSA). Pal-BSA triggered expression of TXNIP and its interaction with NLRP3, resulting in activation of caspase-1 and IL-1β in HRE cells. Silencing Txnip expression in HRE cells abolished Pal-BSA-mediated cleaved IL-1β release into medium and cell death, evident by decreases in cleaved caspase-3 expression and the proportion of live to dead cells.

CONCLUSIONS/INTERPRETATION

These findings provide the first evidence for enhanced TXNIP expression in hypertension and HFD-induced retinal oxidative/inflammatory response and suggest that TXNIP is required for HFD-mediated activation of the NLRP3 inflammasome and the release of IL-1β in endothelial cells.

Sex hormones and biomarkers of neuroprotection and neurodegeneration: implications for female reproductive events in bipolar disorder

OBJECTIVES

Previous studies have suggested that women with bipolar disorder are at higher risk for mood episodes during periods of intense hormonal fluctuation (e.g., premenstrual, postpartum, perimenopause). There is converging literature showing that estrogen and progesterone can modulate neurotransmitter systems and intracellular signaling pathways known to be affected by mood stabilizing agents. Here, we critically review clinical aspects of reproductive cycle events in women with bipolar disorder and preclinical studies, with a focus on the functional interactions between sex hormones and biomarkers of neuroprotection and neurodegeneration that are thought to be involved in the neurobiology of bipolar disorder: brain-derived neurotrophic factor, oxidative stress, and inflammation.

METHODS

A MedLine search using estrogen, progesterone, brain-derived neurotrophic factor, oxidative stress, and inflammation as key words was conducted.

RESULTS

Data showed that estrogen and progesterone closely interact with brain-derived neurotrophic factor, oxidative stress, and inflammation pathways.

CONCLUSIONS

This relationship between sex hormones and the pathways of neuroprotection/neurodegeneration may be relevant to the psychopathological aspects of bipolar disorder in women.

Tenascin-C causes neuronal apoptosis after subarachnoid hemorrhage in rats

The role of tenascin-C (TNC), a matricellular protein, in brain injury is unknown. The aim of this study was to examine if TNC causes neuronal apoptosis after subarachnoid hemorrhage (SAH), a deadly cerebrovascular disorder, using imatinib mesylate (a selective inhibitor of platelet-derived growth factor receptor [PDGFR] that is reported to suppress TNC induction) and recombinant TNC. SAH by endovascular perforation caused caspase-dependent neuronal apoptosis in the cerebral cortex irrespective of cerebral vasospasm development at 24 and 72 h post-SAH, associated with PDGFR activation, mitogen-activated protein kinases (MAPKs) activation, and TNC induction in rats. PDGFR inactivation by an intraperitoneal injection of imatinib mesylate prevented neuronal apoptosis, as well as MAPKs activation and TNC induction in the cerebral cortex at 24 h. A cisternal injection of recombinant TNC reactivated MAPKs and abolished anti-apoptotic effects of imatinib mesylate. The TNC injection also induced TNC itself in SAH brain, which may internally augment neuronal apoptosis after SAH. These findings suggest that TNC upregulation by PDGFR activation causes neuronal apoptosis via MAPK activation, and that the positive feedback mechanisms may exist to augment neuronal apoptosis after SAH. TNC-induced neuronal apoptosis would be a new target to improve outcome after SAH.

Infliximab restores the dysfunctional matrix remodeling protein and growth factor gene expression in patients with inflammatory bowel disease

BACKGROUND

Matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), a disintegrin and metalloprotease with thrombospondin motifs [ADAM(TS)s] and growth factors are involved in inflammation and tissue damage and repair, all occurring in inflammatory bowel disease (IBD). We studied the impact of anti-inflammatory therapy with infliximab on mucosal expression of these tissue remodeling genes in patients with IBD.

METHODS

Mucosal gene expression of 23 MMPs, 4 TIMPs, 50 ADAM(TS)s, and 158 growth factors was investigated in 61 patients with IBD before and after the first infliximab therapy and in 12 controls, with microarrays and quantitative RT-PCR. Protein localization, mucosal gelatinase levels, and net gelatinolytic activity were investigated by immunohistochemistry, zymography analysis, and gelatin degradation assay, respectively.

RESULTS

In patients with active IBD before infliximab versus controls, gene expression of many MMPs, TIMPs, ADAM(TS)s, and growth factors was upregulated, whereas colonic expression of MMP28 and TGFA and ileal expression of ADAMDEC1 and AGT were downregulated. After controlling inflammation with infliximab, most gene dysregulations observed at baseline were restored in responders. Increased ratio of MMP1/TIMP1 expression at baseline in active IBD was restored in responders with colonic mucosal healing. With immunohistochemistry, protein localization differences of MMP1, MMP3, REG1A, and TIMP1 were shown between active IBD and control mucosa. With zymography analysis and gelatin degradation assay, higher gelatinase levels and net gelatinolytic activity were measured before infliximab and levels normalized after infliximab.

CONCLUSIONS

Our data suggest that suppression of inflammation results in the arrest of epithelial damage and subsequent mucosal healing. Therefore, the therapeutic potential of agents targeting MMPs or growth factors as primary therapy seems rather complex.