Blocking tumor cell migration and invasion with biphenyl isoxazole derivative KRIBB3, a synthetic molecule that inhibits Hsp27 phosphorylation

Heat Shock Proteins, a Double-Edged Sword: Significance in Cancer Progression, Chemotherapy Resistance and Novel Therapeutic Perspectives

Heat shock proteins (Hsps) are involved in one of the adaptive mechanisms protecting cells against environmental and metabolic stress. Moreover, the large role of these proteins in the carcinogenesis process, as well as in chemoresistance, was noticed. This review aims to draw attention to the possibilities of using Hsps in developing new cancer therapy methods, as well as to indicate directions for future research on this topic. In order to discuss this matter, a thorough review of the latest scientific literature was carried out, taking into account the importance of selected proteins from the Hsp family, including Hsp27, Hsp40, Hsp60, Hsp70, Hsp90 and Hsp110. One of the more characteristic features of all Hsps is that they play a multifaceted role in cancer progression, which makes them an obvious target for modern anticancer therapy. Some researchers emphasize the importance of directly inhibiting the action of these proteins. In turn, others point to their possible use in the design of cancer vaccines, which would work by inducing an immune response in various types of cancer. Due to these possibilities, it is believed that the use of Hsps may contribute to the progress of oncoimmunology, and thus help in the development of modern anticancer therapies, which would be characterized by higher effectiveness and lower toxicity to the patients.

Microwave assisted one-pot access to pyrazolo quinolinone and tetrahydroisoxazolo quinolinone derivatives via T3P®-DMSO catalysed tandem oxidative-condensation reaction

A new approach for the synthesis of two important annulated pyrazolo quinolinone and tetrahydroisoxazolo quinolinone derivatives from multicomponent reactions was achieved by using T3P®-DMSO-catalysed reactions of stable alcohols, cyclic 1,3-dicarbonyl compounds and amino derivatives of phenyl pyrazoles and isoxazole and has been reported for the first time. This reaction occurred via a tandem oxidative-condensation reaction under microwave irradiation and notable characteristics of this protocol are MCR reactions, shorter reaction time, less waste creation, ease of workup, stable precursors, broad substrate scope and functional group tolerance.

New Oxazolo[5,4-d]pyrimidines as Potential Anticancer Agents: Their Design, Synthesis, and In Vitro Biological Activity Research

Cancer is a large group of diseases in which the rapid proliferation of abnormal cells generally leads to metastasis to surrounding tissues or more distant ones through the lymphatic and blood vessels, making it the second leading cause of death worldwide. The main challenge in designing a modern anticancer therapy is to develop selective compounds that exploit specific molecular targets. In this work, novel oxazolo[5,4-d]pyrimidine derivatives were designed, synthesized, and evaluated in vitro for their cytotoxic activity against a panel of four human cancer cell lines (lung carcinoma: A549, breast adenocarcinoma: MCF7, metastatic colon adenocarcinoma: LoVo, primary colon adenocarcinoma: HT29), along with their P-glycoprotein-inhibitory ability and pro-apoptotic activity. These oxazolo[5,4-d]pyrimidine derivatives, which are structurally similar to nucleic purine bases in general, are characterized by the presence of a pharmacologically favorable isoxazole substituent at position 2 and aliphatic amino chains at position 7 of the condensed heterocyclic system. In silico analysis of the obtained compounds identified their potent inhibitory activity towards human vascular endothelial growth factor receptor-2 (VEGFR-2). Molecular docking was performed to assess the binding mode of new derivatives to the VEGFR-2 active site. Then, their physicochemical, pharmacokinetic, and pharmacological properties (i.e., ADME-administration, distribution, metabolism, and excretion) were also predicted to assess their druglikeness. In particular, compound 3g (with a 3-(N,N-dimethylamino)propyl substituent) was found to be the most potent against the HT29 cell line, with a 50% cytotoxic concentration (CC₅₀) of 58.4 µM, exceeding the activity of fluorouracil (CC₅₀ = 381.2 μM) and equaling the activity of cisplatin (CC₅₀ = 47.2 µM), while being less toxic to healthy human cells (such as normal human dermal fibroblasts (NHDFs)) than these reference drugs. The results suggest that compound 3g is a potentially promising candidate for the treatment of primary colorectal cancer.

Synthesis, in vitro anticancer activity and in silico studies of certain isoxazole-based carboxamides, ureates, and hydrazones as potential inhibitors of VEGFR2

The ensuing research presents the results of in vitro anticancer activity of novel 28 compounds of isoxazole-based carboxamides 3(a-d); ureates 4(a-g), 5, 6, 7a,b, 8; and hydrazones 9(a-f), 10(a-d), 11a,b as potential inhibitors of VEGFR2. The carboxamides and ureates were synthesized by converting 5-(aryl)-isoxzaole-3-carbohydrazides 1a,b to the corresponding carbonylazides 2a,b followed by treatment with the appropriate amines. The hydrazones were directly obtained through condensation of the carbohydrazide 1a,b with aldehydes and/or ketones. The structures of the target compounds were confirmed by elemental and spectral analyses. A preliminary in vitro anticancer screening of solutions (10^-5M) on 60 cancer cell lines (NCI, USA) revealed that the carboxamide 3c is the most promising growth inhibitor. Explicitly, 3c showed potent anticancer activity at 10µ M against leukemia (HL-60(TB), K-562 and MOLT-4), colon cancer (KM12) and melanoma (LOX IMVI) cell lines with %GI range = 70.79-92.21. Evaluation of growth inhibitory activity of the synthesized compounds against hepatocellular carcinoma (HepG2), that overexpresses VEGFR2, showed superior activity of compounds 8, 10a and 10c with IC₅₀ in sub micromolar concentrations of 0.84, 0.79 and 0.69 μM, respectively, which is better than that of the reference drug, Sorafenib (IC₅₀ = 3.99 µM). Moreover, these compounds displayed high selective cytotoxicity for HepG2 cancer cells over the nontumorigenic THLE2 liver cells (SI range = 26.37-38.60) which reflect their safety. The results of VEGFR2 kinase inhibition assay demonstrate that, compounds 8 and 10a are the most active inhibitors with IC₅₀ = 25.7 and 28.2 nM, respectively, (Sorafenib IC₅₀ = 28.1 nM). Molecular docking of the synthesized derivatives to VEGFR2 (PDB: 3WZE) showed similar binding modes to that of the co-crystallized ligand, sorafenib. Moreover, the results of computational assessment of ADME and drug-likeness characteristics inspire further investigations of the new isoxazole-based derivatives to afford more potent, safe and orally active VEGFR2 inhibitors as potential anticancer drug candidates.

Targeting HSF1 as a Therapeutic Strategy for Multiple Mechanisms of EGFR Inhibitor Resistance in EGFR Mutant Non-Small-Cell Lung Cancer

Simple Summary

We attempted to identify target proteins and compounds that can be used to overcome EGFR-TKI resistance in NSCLC. To accomplish this, we generated EGFR inhibitor erlotinib-resistant HCC827-ErlR cells and obtained a list of differentially expressed genes. Then, we performed connectivity map analysis and identified heat shock factor 1 (HSF1) as a potential target protein to overcome erlotinib resistance. Using specific HSF1 shRNAs and KRIBB11 (N²-(1H-Indazol-5-yl)-N⁶-methyl-3-nitropyridine-2,6-diamine), we proved the effectiveness of HSF1 inhibition for overcoming erlotinib resistance in vitro. In addition, we proved the efficacy of emetine in inhibiting HSF1 activity and the tumor growth of erlotinib-resistant PC9-ErlR cells in a mouse model.

Abstract

Although EGFR-TKI treatment of NSCLC (non-small-cell lung cancer) patients often achieves profound initial responses, the efficacy is transient due to acquired resistance. Multiple receptor tyrosine kinase (RTK) pathways contribute to the resistance of NSCLC to first- and third-generation EGFR-TKIs, such as erlotinib and osimertinib. To identify potential targets for overcoming EGFR-TKI resistance, we performed a gene expression signature-based strategy using connectivity map (CMap) analysis. We generated erlotinib-resistant HCC827-ErlR cells, which showed resistance to erlotinib, gefitinib, osimertinib, and doxorubicin. A list of differentially expressed genes (DEGs) in HCC827-ErlR cells was generated and queried using CMap analysis. Analysis of the top 4 compounds from the CMap list suggested HSF1 as a potential target to overcome EGFR-TKI resistance. HSF1 inhibition by using HSF1 shRNAs or KRIBB11 decreased the expression of HSF1 downstream proteins, such as HSP70 and HSP27, and also decreased the expression of HSP90/HSP70/BAG3 client proteins, such as BCL2, MCL1, EGFR, MET, and AXL, causing apoptosis of EGFR-TKI-resistant cancer cells. Finally, we demonstrated the efficacy of the HSF1 inhibitor on PC9-ErlR cells expressing mutant EGFR (T790M) in vivo. Collectively, these findings support a targetable HSF1-(HSP90/HSP70/BAG3)-(BCL2/MCL1/EGFR/MET/AXL) pathway to overcome multiple mechanisms of EGFR-TKI resistance.

In silico screening and exploration into phenotypic alterations of deleterious oncogenic single nucleotide polymorphisms in HSPB1 gene

A small heat shock protein, HSP27, encoded by HSPB1 gene strongly favors survival, proliferation and metastasis of cancer cells and its expression is dependent on post-translational modifications like phosphorylation. This study performed an extensive in silico screening of 20 deleterious non-synonymous SNPs in the coding region of HSPB1 gene, among which four were identified to be cancer associated. The SNP variant I181S introduced a new phosphorylation site in position 181, which might elevate the protein's activation potential. Emergence of other post-translational modifications was also observed in SNP variants: L144P and E130K.Significant conformational changes were observed in I181S, L144P and E130K SNP variants with respect to wild-type HSP27. These SNPs appear in one among 10⁵ individuals, making them more susceptible towards cancer. This study would therefore, instigate development of novel biomarkers for cancer risk detection and would provide a detailed understanding towards varied cancer susceptibility of human population.

Bio-indicators in cadmium toxicity: Role of HSP27 and HSP70

Heat shock proteins (HSPs) are a family of proteins that are expressed by cells in reply to stressors. The changes in concentration of HSPs could be utilized as a bio-indicator of oxidative stress caused by heavy metal. Exposure to the different heavy metals may induce or reduce the expression of different HSPs. The exposure to cadmium ion (Cd²⁺) could increase HSP70 and HSP27 over 2- to 10-fold or even more. The in vitro and in vivo models indicate that the HSP70 family is more sensitive to Cd intoxication than other HSPs. The analyses of other HSPs along with HSP70, especially HSP27, could also be useful to obtain more accurate results. In this regard, this review focuses on examining the literature to bold the futuristic uses of HSPs as bio-indicators in the initial assessment of Cd exposure risks in defined environments.

Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development

Stress proteins (SPs) including heat-shock proteins (HSPs), RNA chaperones, and ER associated stress proteins are molecular chaperones essential for cellular homeostasis. The major functions of HSPs include chaperoning misfolded or unfolded polypeptides, protecting cells from toxic stress, and presenting immune and inflammatory cytokines. Regarded as a double-edged sword, HSPs also cooperate with numerous viruses and cancer cells to promote their survival. RNA chaperones are a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which are essential factors for manipulating both the functions and metabolisms of pre-mRNAs/hnRNAs transcribed by RNA polymerase II. hnRNPs involve in a large number of cellular processes, including chromatin remodelling, transcription regulation, RNP assembly and stabilization, RNA export, virus replication, histone-like nucleoid structuring, and even intracellular immunity. Dysregulation of stress proteins is associated with many human diseases including human cancer, cardiovascular diseases, neurodegenerative diseases (e.g., Parkinson’s diseases, Alzheimer disease), stroke and infectious diseases. In this review, we summarized the biologic function of stress proteins, and current progress on their mechanisms related to virus reproduction and diseases caused by virus infections. As SPs also attract a great interest as potential antiviral targets (e.g., COVID-19), we also discuss the present progress and challenges in this area of HSP-based drug development, as well as with compounds already under clinical evaluation.

Design, Synthesis and Characterization of Novel Isoxazole Tagged Indole Hybrid Compounds

Sixteen new isoxazole tagged indole compounds have been synthesized via copper (I) catalyzed click chemistry of the aryl hydroxamoyl chloride and an indole containing alkyne moiety. The chemical structure of the synthesized compounds has been established using various physicochemical techniques. X-ray single crystal analysis of Ethyl 1-((3-phenylisoxazol-5-yl) methyl)-1H-indole-2-carboxylate (8a) has been analyzed. All compounds were tested for their antibacterial and anticancer activities. The activities for the new compounds were weak against both bacterial strains and the cancer cell lines.

Ivermectin inhibits HSP27 and potentiates efficacy of oncogene targeting in tumor models

HSP27 is highly expressed in, and supports oncogene addiction of, many cancers. HSP27 phosphorylation is a limiting step for activation of this protein and a target for inhibition, but its highly disordered structure challenges rational structure-guided drug discovery. We performed multistep biochemical, structural, and computational experiments to define a spherical 24-monomer complex composed of 12 HSP27 dimers with a phosphorylation pocket flanked by serine residues between their N-terminal domains. Ivermectin directly binds this pocket to inhibit MAPKAP2-mediated HSP27 phosphorylation and depolymerization, thereby blocking HSP27-regulated survival signaling and client-oncoprotein interactions. Ivermectin potentiated activity of anti-androgen receptor and anti-EGFR drugs in prostate and EGFR/HER2-driven tumor models, respectively, identifying a repurposing approach for cotargeting stress-adaptive responses to overcome resistance to inhibitors of oncogenic pathway signaling.

Oxidative stress-induced activation of Abl and Src kinases rapidly induces P-glycoprotein internalization via phosphorylation of caveolin-1 on tyrosine-14, decreasing cortisol efflux at the blood-brain barrier

Exposure of the brain to high levels of glucocorticoids during ischemia-reperfusion induces neuronal cell death. Oxidative stress alters blood-brain barrier (BBB) function during ischemia-reperfusion, and so we hypothesized that it might impair P-glycoprotein (P-gp)-mediated efflux transport of glucocorticoids at the BBB. Therefore, the purpose of this study was to clarify the molecular mechanism of this putative decrease of P-gp-mediated efflux function. First, we established that H₂O₂ treatment of a human in vitro BBB model (hCMEC/D3) reduced both P-gp efflux transport activity and protein expression on the plasma membrane within 20 min. These results suggested that the rapid decrease of efflux function might be due to internalization of P-gp. Furthermore, H₂O₂ treatment markedly increased tyrosine-14-phosphorylated caveolin-1, which is involved in P-gp internalization. A brain perfusion study in rats showed that cortisol efflux at the BBB was markedly decreased by H₂O₂ administration, and inhibitors of Abl kinase and Src kinase, which phosphorylate tyrosine-14 in caveolin-1, suppressed this decrease. Overall, these findings support the idea that oxidative stress-induced activation of Abl kinase and Src kinase induces internalization of P-gp via the phosphorylation of tyrosine-14 in caveolin-1, leading to a rapid decrease of P-gp-mediated cortisol efflux at the BBB.

A novel CD147 inhibitor, SP-8356, reduces neointimal hyperplasia and arterial stiffness in a rat model of partial carotid artery ligation

Background

Neointimal hyperplasia and its related arterial stiffness are the crucial pathophysiological features in atherosclerosis and in-stent restenosis. Cluster of differentiation 147 (CD147), a member of the immunoglobulin super family that induces the expression of matrix metalloproteinase-9 (MMP-9) by dimerization, may play important roles in neointimal hyperplasia and may therefore be an effective target for the treatment of this condition. Here, we investigated whether a novel CD147 inhibitor SP-8356 ((1S,5R)-4-(3,4-dihydroxy-5-methoxystyryl)-6,6-dimethylbicyclo[3.1.1]hept-3-en-2-one) reduces neointimal hyperplasia and arterial stiffness in a rat model of partial carotid artery ligation.

Methods

Neointimal hyperplasia was induced in Sprague–Dawley rats by partial ligation of the right carotid artery combined with a high fat diet and vitamin D injection. Rats were subdivided into vehicle, SP-8356 (50 mg/kg), and rosuvastatin (10 mg/kg) groups. The drugs were administrated via intraperitoneal injections for 4 weeks. The elasticity of blood vessels was assessed by measuring pulse wave velocity using Doppler ultrasonography before sacrifice. Histomolecular analysis was carried out on harvested carotid arteries.

Results

SP-8356 significantly reduced MMP activity by inhibiting CD147 dimerization. SP-8356 reduced neointimal hyperplasia and prevented the deterioration of vascular elasticity. SP-8356 had a greater inhibitory effect on neointimal hyperplasia than did rosuvastatin. Furthermore, rosuvastatin did not improve vascular elasticity. SP-8356 increased the expression of smooth muscle myosin heavy chain (SM-MHC), but decreased the expression of collagen type III and MMP-9 in the neointimal region. In contrast to SP-8356, rosuvastatin did not alter the expression of SM-MHC or MMP-9.

Conclusions

The ability of SP-8356 to reduce neointimal hyperplasia and improve arterial stiffness in affected carotid artery suggests that SP-8356 could be a promising therapeutic drug for vascular remodeling disorders involving neointimal hyperplasia and arterial stiffness.

Heat Shock Protein 27 Phosphorylation Regulates Tumor Cell Migration under Shear Stress

Heat shock protein 27 (HSP27) is a multifunctional protein that undergoes significant changes in its expression and phosphorylation in response to shear stress stimuli, suggesting that it may be involved in mechanotransduction. However, the mechanism of HSP27 affecting tumor cell migration under shear stress is still not clear. In this study, HSP27-enhanced cyan fluorescent protein (ECFP) and HSP27-Ypet plasmids are constructed to visualize the self-polymerization of HSP27 in living cells based on fluorescence resonance energy transfer technology. The results show that shear stress induces polar distribution of HSP27 to regulate the dynamic structure at the cell leading edge. Shear stress also promotes HSP27 depolymerization to small molecules and then regulates polar actin accumulation and focal adhesion kinase (FAK) polar activation, which further promotes tumor cell migration. This study suggests that HSP27 plays an important role in the regulation of shear stress-induced HeLa cell migration, and it also provides a theoretical basis for HSP27 as a potential drug target for metastasis.

Mesenchymal MAPKAPK2/HSP27 drives intestinal carcinogenesis

Mesenchymal cells in the microenvironment of cancer exert important functions in tumorigenesis; however, little is known of intrinsic pathways that mediate these effects. MAPK signals, such as from MAPKAPK2 (MK2) are known to modulate tumorigenesis, yet their cell-specific role has not been determined. Here, we studied the cell-specific role of MK2 in intestinal carcinogenesis using complete and conditional ablation of MK2. We show that both genetic and chemical inhibition of MK2 led to decreased epithelial cell proliferation, associated with reduced tumor growth and invasive potential in the Apc^min/+ mouse model. Notably, this function of MK2 was not mediated by its well-described immunomodulatory role in immune cells. Deletion of MK2 in intestinal mesenchymal cells (IMCs) led to both reduced tumor multiplicity and growth. Mechanistically, MK2 in IMCs was required for Hsp27 phosphorylation and the production of downstream tumorigenic effector molecules, dominantly affecting epithelial proliferation, apoptosis, and angiogenesis. Genetic ablation of MK2 in intestinal epithelial or endothelial cells was less effective in comparison with its complete deletion, leading to reduction of tumor size via modulation of epithelial apoptosis and angiogenesis-associated proliferation, respectively. Similar results were obtained in a model of colitis-associated carcinogenesis, indicating a mesenchymal-specific role for MK2 also in this model. Our findings demonstrate the central pathogenic role of mesenchymal-specific MK2/Hsp27 axis in tumorigenesis and highlight the value of mesenchymal MK2 inhibition in the treatment of cancer.

Multicomponent reactions: a sustainable tool to 1,2- and 1,3-azoles

The present review outlines the recent advancements and pioneering efforts on the synthesis of 1,2/1,3-azoles employing a multicomponent strategy.

Ultrasound-assisted facile one-pot sequential synthesis of novel sulfonamide-isoxazoles using cerium (IV) ammonium nitrate (CAN) as an efficient oxidant in aqueous medium

A series of novel 3,5-disubstituted isoxazoles have been synthesized, using a new, green, and versatile "one-pot three-steps" methodology. The key step is an oxidative 1,3-dipolar cycloaddition under ultrasonic irradiation, occurring in aqueous media, and mediated by cerium (IV) ammonium nitrate (CAN). CAN is a one-electron oxidant, highly soluble in water, slightly toxic and inexpensive, that allows the in situ conversion of the intermediate aldoximes into nitrile oxide. The syntheses are highly regioselective, as illustrated by the structures of the final compounds, which have been fully assessed by spectral analyses (¹H and ¹³C NMR, MS). This study illustrates the potency of the ultrasound activation to synthesize a set of highly functionalized heterocycles, with potential applications in biology, in short reaction times and following an eco-friendly process.

Synthesis and biological evaluation of triazole and isoxazole-tagged benzothiazole/benzoxazole derivatives as potent cytotoxic agents

Cancer is a major health problem and the most upsetting disease in humans, leading to death in both developed and developing countries.

Overexpression of NEDD9 in renal cell carcinoma is associated with tumor migration and invasion

Scaffold protein neural precursor cell expressed, developmentally downregulated 9 (NEDD9) is a member of the Crk-associated substrate protein family and is known to be a biomarker in multiple cancer types. It serves a critical function in regulating cell proliferation, migration, invasion and survival. The objective of this study was to evaluate the potential effects of NEDD9 in renal cell carcinoma (RCC). The expression of NEDD9 was analyzed by immunohistochemistry, western blotting and reverse transcription-quantitative polymerase chain reaction. NEDD9 protein and mRNA levels were significantly upregulated in RCC tissues compared with normal tissues (P<0.001). Furthermore, the NEDD9 immunostaining level was significantly associated with primary tumor stage and tumor, node, metastasis stage (P<0.05). High NEDD9 expression resulted in significantly lower survival rates for patients compared with normal NEDD9 expression (P<0.01). In addition, wound healing and transwell assays indicated that NEDD9 depletion by small interfering RNA significantly attenuated the migration and invasion of RCC cells (P<0.001). The present data suggested that NEDD9 may be a novel target for prevention and treatment of RCC metastasis and recurrence.

Isoxazole ring as a useful scaffold in a search for new therapeutic agents

Due to its relatively easy synthesis, isoxazole ring has been as an object of interest for chemists and pharmacologists from research groups all over the world. Its chemical modifications include both connection of isoxazole with other aromatic, heteroaromatic or non aromatic rings and substitution with different alkyl groups. Thanks to their usually low cytotoxicity, isoxazole derivatives are still popular scaffolds for the development of new agents with variable biological activities, such as antimicrobial, antiviral, anticancer, anti-inflammatory, immunomodulatory, anticonvulsant or anti-diabetic properties. This review discusses the chemical structure of recently developed isoxazole derivatives with regards to their activity and potential therapeutic use.

Protein kinase D signaling in cancer: A friend or foe?

Protein kinase D is a family of evolutionarily conserved serine/threonine kinases that belongs to the Ca⁺⁺/Calmodulin-dependent kinase superfamily. Signal transduction pathways mediated by PKD can be triggered by a variety of stimuli including G protein-coupled receptor agonists, growth factors, hormones, and cellular stresses. The regulatory mechanisms and physiological roles of PKD have been well documented including cell proliferation, survival, migration, angiogenesis, regulation of gene expression, and protein/membrane trafficking. However, its precise roles in disease progression, especially in cancer, remain elusive. A plethora of studies documented the cell- and tissue-specific expressions and functions of PKD in various cancer-associated biological processes, while the causes of the differential effects of PKD have not been thoroughly investigated. In this review, we have discussed the structural-functional properties, activation mechanisms, signaling pathways and physiological functions of PKD in the context of human cancer. Additionally, we have provided a comprehensive review of the reported tumor promoting or tumor suppressive functions of PKD in several major cancer types and discussed the discrepancies that have been raised on PKD as a major regulator of malignant transformation.

Copper nitrate-mediated chemo- and regioselective annulation from two different alkynes: a direct route to isoxazoles

An efficient copper nitrate-mediated chemo- and regioselective annulation reaction of two different alkynes was developed to achieve polysubstituted isoxazoles.

Bradykinin stimulates protein kinase D-mediated colonic myofibroblast migration via cyclooxygenase-2 and heat shock protein 27

BACKGROUND

Inflammatory bowel disease is characterized by episodic intestinal injury and repair. Myofibroblasts are gastrointestinal tract stromal cells that regulate the reparative process and are known targets of inflammatory mediators including bradykinin (BK). However, the mechanisms through which inflammation regulates myofibroblast-induced wound healing remain incompletely understood. Here, we demonstrate, for the first time, that BK stimulates myofibroblast migration through protein kinase D (PKD)-mediated activation of the cyclooxygenase-2 (COX-2) and heat shock protein 27 (Hsp27) pathways.

MATERIALS AND METHODS

CCD-18Co is a human colonic myofibroblast cell line used from passages 8 to 14. An in vitro scratch assay assessed the effect of BK (100 nM) on myofibroblast migration over 24 h in the presence or absence of several inhibitors (CID755673 [10 μM] and NS398 [10 μM]). Hsp27 small interfering RNA evaluated the effect of Hsp27 on colonic myofibroblast migration. Antibodies to pPKD, pHsp27, and COX-2 evaluated expression levels by Western blot.

RESULTS

BK stimulated myofibroblast migration over 24 h. BK also led to rapid and sustained phosphorylation of PKD at Ser-916, rapid phosphorylation of Hsp27 at Ser-82, and increased COX-2 expression over 4 h. BK-mediated COX-2 expression and Hsp27 phosphorylation were both inhibited by the PKD inhibitor CID755673. Similarly, BK-induced myofibroblast migration was significantly inhibited by CID755673 (P < 0.05), by the direct COX-2 inhibitor NS398 (P < 0.05), and by Hsp27 small interfering RNA (P < 0.05).

CONCLUSIONS

BK stimulates myofibroblast migration through PKD-mediated activation of COX-2 and Hsp27. PKD, COX-2, and Hsp27 all appear to regulate myofibroblast cell migration, a stromal population that may play an important role in mucosal healing in the setting of inflammation.

RNA Interference-based Investigation of the Function of Heat Shock Protein 27 during Corneal Epithelial Wound Healing

Small interfering RNA (siRNA) is among the most widely used RNA interference methods for the short-term silencing of protein-coding genes. siRNA is a synthetic RNA duplex created to specifically target a mRNA transcript to induce its degradation and it has been used to identify novel pathways in various cellular processes. Few reports exist regarding the role of phosphorylated heat shock protein 27 (HSP27) in corneal epithelial wound healing. Herein, cultured human corneal epithelial cells were divided into a scrambled control-siRNA transfected group and a HSP27-specific siRNA-transfected group. Scratch-induced directional wounding assays, and western blotting, and flow cytometry were then performed. We conclude that HSP27 has roles in corneal epithelial wound healing that may involve epithelial cell apoptosis and migration. Here, step-by-step descriptions of sample preparation and the study protocol are provided.

TNF-α stimulates colonic myofibroblast migration via COX-2 and Hsp27

BACKROUND

Crohn's disease (CD) is a chronic inflammatory enteropathy characterized by fibrotic strictures. Myofibroblasts (MFBs) are stromal cells of the gastrointestinal tract found in increased numbers in patients with CD and represent the key effector cells involved in pathologic fibrosis. MFB is a known target of tumor necrosis factor alpha (TNF-α), a proinflammatory cytokine strongly implicated in the pathophysiology of CD. However, the precise mechanisms through which TNF-α contributes to fibrosis remain incompletely understood. Here, we demonstrate for the first time that TNF-α increases MFB migration through the cyclooxygenase 2 (COX-2) and heat-shock protein 27 (Hsp27) pathways.

MATERIALS AND METHODS

The human colonic MFB cell line 18Co was grown to confluence on 35 × 10 mm cell culture dishes and used from passages 8-14. An in vitro scratch assay assessed the effect of TNF-α (10 ng/mL) on MFB migration over 24 h in the presence or absence of several inhibitors (NS398, SB203580, Hsp27 siRNA).

RESULTS

TNF-α significantly increased MFB migration over 24 h. TNF-α also led to the increased expression of COX-2 and stimulated rapid phosphorylation of Hsp27 at serine 82. TNF-α-induced COX-2 expression, Hsp27 phosphorylation, and MFB migration were all significantly inhibited by the P38 MAPK inhibitor SB203580 (P < 0.05). TNF-α-induced MFB migration was also significantly inhibited by NS398 (P < 0.05), a direct inhibitor of COX-2, and by siRNA targeting Hsp27 (P < 0.05).

CONCLUSIONS

TNF-α stimulates colonic MFB migration through P38 MAPK-mediated activation of COX-2 and Hsp27. Further elucidating these inflammatory signaling pathways may lead to novel therapeutic targets for the treatment of CD-related fibrosis and strictures.

Synthesis, antimycobacterial screening and ligand-based molecular docking studies on novel pyrrole derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties

We report here the synthesis, antibacterial and antitubercular evaluation of 61 novel pyrrolyl derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties. Molecular docking was carried out on enoyl ACP reductase from Mycobacterium tuberculsosis using Surflex-Dock, which is one of the key enzymes involved in type II fatty acid biosynthetic pathway of Mycobacterium tuberculosis, an attractive target for designing novel antitubercular agents. Docking analysis of the crystal structure of ENR performed using Surflex-Dock in Sybyl-X 2.0 software indicates the occupation of substituted pyrrolyl derivatives into hydrophobic pocket of InhA enzyme. Compounds 9b and 9d exhibited the highest antitubercular activity almost close to isoniazid (0.4 μg/mL) with a MIC value of 0.8 μg/mL. All other compounds showed the good activity with a MIC value of 6.25-100 μg/mL. The compounds were further tested for mammalian cell toxicity using human lung cancer cell-line (A549) and were nontoxic. Some compounds exhibited inhibition activities against InhA.

Evaporative edge lithography of a liposomal drug microarray for cell migration assays

Lipid multilayer microarrays are a promising approach to miniaturize laboratory procedures by taking advantage of the microscopic compartmentalization capabilities of lipids. Here, we demonstrate a new method to pattern lipid multilayers on surfaces based on solvent evaporation along the edge where a stencil contacts a surface called evaporative edge lithography (EEL). As an example of an application of this process, we use EEL to make microarrays suitable for a cell-based migration assay. Currently existing cell migration assays require a separate compartment for each drug which is dissolved at a single concentration in solution. An advantage of the lipid multilayer microarray assay is that multiple compounds can be tested on the same surface. We demonstrate this by testing the effect of two different lipophilic drugs, Taxol and Brefeldin A, on collective cell migration into an unpopulated area. This particular assay should be scalable to test of 2000 different lipophilic compounds or dosages on a standard microtiter plate area, or if adapted for individual cell migration, it would allow for high-throughput screening of more than 50,000 compounds per plate.

Crystal structure of 5-(1-benzofuran-2-yl)-3-(4-methylphenyl)-4,5-dihydro-1,2-oxazol-5-ol

In the title compound, C₁₈H₁₅NO₃, the isoxazole moiety adopts a shallow envelope conformation, with the C atom bearing the OH group displaced by 0.148 (1) Å from the mean plane through the other four atoms. The mean plane of this ring (all atoms) subtends dihedral angles of 87.19 (6) and 15.51 (7)° with the benzo­furan ring system (r.m.s. deviation = 0.007 Å) and the 4-methylphenyl ring, respectively. In the crystal, mol­ecules are linked by O—H⋯N hydrogen bonds, generating [001] C(5) chains, with adjacent mol­ecules in the chain related by c-glide symmetry. Weak C—H⋯O inter­actions link the chains into a three-dimensional network.

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis

One of the important 'hallmarks' of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.

Interferon-β counter-regulates its own pro-apoptotic action by activating p38 MAPK signalling in human SH-SY5Y neuroblastoma cells

Type I interferons (IFNs) induce apoptosis of neuroblastoma cells, but the molecular mechanisms regulating this event have not been completely elucidated. Here, we investigated the role of p38 mitogen activated protein kinase (MAPK) activity, a key regulator of apoptosis and a known modulator of IFN-induced responses in non-neuronal cells. We show that in SH-SY5Y human neuroblastoma cells IFN-β induced a delayed and sustained increase of p38 MAPK activity through a novel mechanism involving the sequential activation of Janus kinase-signal transducer and activator of transcription-1 signalling, enhanced expression of the NADPH oxidase catalytic subunit gp91(phox), increased reactive oxygen species production and stimulation of the MAPK kinase kinase transforming growth factor-β-activated kinase 1. Either blockade of p38 MAPK by the second generation inhibitors BIRB0796 and VX745 or siRNA knockdown of p38α MAPK enhanced IFN-β-induced apoptosis of neuroblastoma cells. Exposure to IFN-β increased the phosphorylation of the small heat shock protein HSP27 at Ser15, Ser78 and Ser82 with a time course similar to p38 MAPK activation and this response was suppressed by either p38α MAPK depletion or pharmacological inhibition of p38 MAPK and MAPK-activated protein kinase 2 (MK2). Either silencing of HSP27 expression by siRNA or MK2 inhibition potentiated IFN-β-induced apoptotic death. These results indicate that IFN-β-induced apoptosis of human SH-SY5Y neuroblastoma cells is associated with a long-lasting up-regulation of p38 MAPK activity, stimulation of MK2 and phosphorylation of the pro-survival protein HSP27. Moreover, the data show that inhibition of p38 MAPK signalling potentiates the anti-neuroblastoma activity of the cytokine, indicating that this pathway mediates a counter-regulatory response.

Monocyte Proteomics Reveals Involvement of Phosphorylated HSP27 in the Pathogenesis of Osteoporosis

Peripheral monocytes, precursors of osteoclasts, have emerged as important candidates for identifying proteins relevant to osteoporosis, a condition characterized by low Bone Mineral Density (BMD) and increased susceptibility for fractures. We employed 4-plex iTRAQ (isobaric tags for relative and absolute quantification) coupled with LC-MS/MS (liquid chromatography coupled with tandem mass spectrometry) to identify differentially expressed monocyte proteins from premenopausal and postmenopausal women with low versus high BMD. Of 1801 proteins identified, 45 were differentially abundant in low versus high BMD, with heat shock protein 27 (HSP27) distinctly upregulated in low BMD condition in both premenopausal and postmenopausal categories. Validation in individual samples (n = 80) using intracellular ELISA confirmed that total HSP27 (tHSP27) as well as phosphorylated HSP27 (pHSP27) was elevated in low BMD condition in both categories (P < 0.05). Further, using transwell assays, pHSP27, when placed in the upper chamber, could increase monocyte migration (P < 0.0001) and this was additive in combination with RANKL (receptor activator of NF_kB ligand) placed in the lower chamber (P = 0.05). Effect of pHSP27 in monocyte migration towards bone milieu can result in increased osteoclast formation and thus contribute to pathogenesis of osteoporosis. Overall, this study reveals for the first time a novel link between monocyte HSP27 and BMD.