Micellar paclitaxel improves severe psoriasis in a prospective phase II pilot study

A Route for Investigating Psoriasis: From the Perspective of the Pathological Mechanisms and Therapeutic Strategies of Cancer

Psoriasis is an incurable skin disease that develops in about two-thirds of patients before the age of 40 and requires lifelong treatment; its pathological mechanisms have not been fully elucidated. The core pathological process of psoriasis is epidermal thickening caused by the excessive proliferation of epidermal keratinocytes, which is similar to the key feature of cancer; the malignant proliferation of cancer cells causes tumor enlargement, suggesting that there is a certain degree of commonality between psoriasis and cancer. This article reviews the pathological mechanisms that are common to psoriasis and cancer, including the interaction between cell proliferation and an abnormal immune microenvironment, metabolic reprogramming, and epigenetic reprogramming. In addition, there are common therapeutic agents and drug targets between psoriasis and cancer. Thus, psoriasis and cancer share a common pathological mechanisms-drug targets-therapeutic agents framework. On this basis, it is proposed that investigating psoriasis from a cancer perspective is beneficial to enriching the research strategies related to psoriasis.

Tacrolimus and paclitaxel co-loaded O/O ointment without surfactant: Synergistic combinations for the treatment of psoriasis

Psoriasis is an autoimmune disorder disease with abnormally activated T lymphocytes and thickening of the epidermis. The mechanism of the action of tacrolimus and paclitaxel are matched with the two only known pathogenesis of psoriasis. However, there has been no report on tacrolimus combined with paclitaxel in the treatment of psoriasis until now. The O/O ointment was prepared for the topical application to overcome poor solubility, poor skin penetration, and erratic absorption of the two drugs. A high-speed shearing method was adopted to prepare the ointment, in which propylene carbonate was used to solve tacrolimus and paclitaxel completely. The ointment showed excellent stability, slow release of the drugs, better retention in psoriatic skin, and good skin tolerance. The therapeutic efficacy of ointment was evaluated with imiquimod induced psoriatic model, and the level of expression of psoriatic biochemical markers was evaluated using the PASI score and immunohistochemistry. The cumulative PASI score was 10.8 for the imiquimod induced group, 7.8 for the tacrolimus ointment group, 8.3 for the paclitaxel ointment and 5.3 for the tacrolimus-paclitaxel (1:1) ointment group, respectively. Ointment group with tacrolimus and paclitaxel indicated a significant improvement in the phenotypic features of the psoriatic skin treated. Compared with the imiquimod group, tacrolimus-paclitaxel (1:1) ointment group was significantly reduced the level of IL-17. The results confirm that tacrolimus and paclitaxel co-loaded ointment can be an effective strategy for the treatment of psoriasis.

Substances of Natural Origin in Medicine: Plants vs. Cancer

Continuous monitoring of the population's health is the main method of learning about disease prevalence. National and international data draw attention to the persistently high rates of cancer incidence. This necessitates the intensification of efforts aimed at developing new, more effective chemotherapeutic and chemopreventive drugs. Plants represent an invaluable source of natural substances with versatile medicinal properties. Multidirectional activities exhibited by natural substances and their ability to modulate key signaling pathways, mainly related to cancer cell death, make these substances an important research direction. This review summarizes the information regarding plant-derived chemotherapeutic drugs, including their mechanisms of action, with a special focus on selected anti-cancer drugs (paclitaxel, irinotecan) approved in clinical practice. It also presents promising plant-based drug candidates currently being tested in clinical and preclinical trials (betulinic acid, resveratrol, and roburic acid).

Perspective insights of small molecules, phytoconstituents and biologics in the management of psoriasis: A focus on targeting major inflammatory cytokine pathways

Psoriasis is an enduring, pruritic and papulosquamous skin ailment that poses a significant burden on public health. It is mainly characterized by hyperkeratosis, acanthosis, parakeratosis, scaly and erythematous plaques. Biomarkers like interleukin-17, interleukin-12 and -23 and tumor necrosis factor-α serve as key drivers of psoriatic pathogenesis. Triggered release of pro-inflammatory cytokines from various up-regulated pathways leads to psoriatic inflammation. Several target moieties like biologics, small molecules and herbal moieties play a fundamental role in the repression of pathogenesis of psoriasis. Biologics and small molecules engaged in the management of psoriasis have been emphasized in detail. An insight into nano-carrier interventions on herbal moieties and clinical aspects of psoriasis are also highlighted. This review emphasizes various pathological targets involved in psoriasis.

Genetic approaches in improving biotechnological production of taxanes: An update

Paclitaxel (PTX) and its derivatives are diterpene alkaloids widely used as chemotherapeutic agents in the treatment of various types of cancer. Due to the scarcity of PTX in nature, its production in cell cultures and plant organs is a major challenge for plant biotechnology. Although significant advances have been made in this field through the development of metabolic engineering and synthetic biology techniques, production levels remain insufficient to meet the current market demand for these powerful anticancer drugs. A key stumbling block is the difficulty of genetically transforming the gymnosperm Taxus spp. This review focuses on the progress made in improving taxane production through genetic engineering techniques. These include the overexpression of limiting genes in the taxane biosynthetic pathway and transcription factors involved in its regulation in Taxus spp. cell cultures and transformed roots, as well as the development and optimization of transformation techniques. Attempts to produce taxanes in heterologous organisms such as bacteria and yeasts are also described. Although promising results have been reported, the transfer of the entire PTX metabolic route has not been possible to date, and taxane biosynthesis is still restricted to Taxus cells and some endophytic fungi. The development of a synthetic organism other than Taxus cells capable of biotechnologically producing PTX will probably have to wait until the complete elucidation of its metabolic pathway.

Bioinformatics Identification of Ferroptosis-Associated Biomarkers and Therapeutic Compounds in Psoriasis

Purpose. Psoriasis is closely linked to ferroptosis. This study aimed to identify potential ferroptosis-associated genes in psoriasis using bioinformatics. Methods. Data from the GSE30999 dataset was downloaded from the Gene Expression Omnibus (GEO), and the ferroptosis-associated genes were retrieved from FerrDb. The differentially expressed ferroptosis-associated genes were identified using Venn diagrams. Subsequently, a network of protein-protein interactions (PPIs) between psoriasis targets and ferroptosis-associated genes was constructed based on the STRING database and analyzed by Cytoscape software. The Metascape portal conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Moreover, the expression of ferroptosis-related genes was verified in the GSE13355 dataset. Finally, the verified genes were used to predict the therapeutic drugs for psoriasis using the DGIdb/CMap database. SwissDock was used to examine ligand docking, and UCSF Chimera displayed the results visually. Results. Among 85 pairs of psoriasis lesion (LS) and no-lesion (NL) samples from patients, 19 ferroptosis-associated genes were found to be differentially expressed (3 upregulated genes and 16 downregulated genes). Based on the PPI results, these ferroptosis-associated genes interact with each other. The GO and KEGG enrichment analysis of differentially expressed ferroptosis-related genes indicated several enriched terms related to the oxidative stress response. The GSE13355 dataset verified the results of the bioinformatics analysis obtained from the GSE30999 dataset regarding SLC7A5, SLC7A11, and CHAC1. Psoriasis-related compounds corresponding to SLC7A5 and SLC7A11 were also identified, including Melphalan, Quisqualate, Riluzole, and Sulfasalazine. Conclusion. We identified 3 differentially expressed ferroptosis-related genes through bioinformatics analysis. SLC7A5, SLC7A11, and CHAC1 may affect the development of psoriasis by regulating ferroptosis. These results open new avenues in understanding the treatment of psoriasis.

Insights into the control of taxane metabolism: Molecular, cellular, and metabolic changes induced by elicitation in Taxus baccata cell suspensions

More knowledge is needed about the molecular/cellular control of paclitaxel (PTX) production in Taxus spp. cell cultures. In this study, the yield of this anticancer agent in Taxus baccata cell suspensions was improved 11-fold after elicitation with coronatine (COR) compared to the untreated cells, and 18-fold when co-supplemented with methyl-β-cyclodextrins (β-CDs). In the dual treatment, the release of taxanes from the producer cells was greatly enhanced, with 81.6% of the total taxane content being found in the medium at the end of the experiment. The experimental conditions that caused the highest PTX production also induced its maximum excretion, and increased the expression of taxane biosynthetic genes, especially the flux-limiting BAPT and DBTNBT. The application of COR, which activates PTX biosynthesis, together with β - CDs, which form inclusion complexes with PTX and related taxanes, is evidently an efficient strategy for enhancing PTX production and release to the culture medium. Due to the recently described role of lipid droplets (LDs) in the trafficking and accumulation of hydrophobic taxanes in Taxus spp. cell cultures, the structure, number and taxane storage capacity of these organelles was also studied. In elicited cultures, the number of LDs increased and they mainly accumulated taxanes with a side chain, especially PTX. Thus, PTX constituted up to 50-70% of the total taxanes found in LDs throughout the experiment in the COR + β - CD-treated cultures. These results confirm that LDs can store taxanes and distribute them inside and outside cells.

Repurposing approved therapeutics for new indication: Addressing unmet needs in psoriasis treatment

Psoriasis is a chronic inflammatory autoimmune condition manifested by the hyperproliferation of keratinocytes with buildup of inflammatory red patches and scales on skin surfaces. The available treatment options for the management of psoriasis have various drawbacks, and the clinical need for effective therapeutics for this disease remain unmet; therefore, the approaches of drug repurposing or drug repositioning could potentially be used for treating indications of psoriasis. The undiscovered potential of drug repurposing or repositioning compensates for the limitations and hurdles in drug discovery and drug development processes. Drugs initially approved for other indications, including anticancer, antidiabetic, antihypertensive, and anti-arthritic activities, are being investigated for their potential in psoriasis management as a new therapeutic indication by using repurposing strategies. This article envisages the potential of various therapeutics for the management of psoriasis.

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Psoriasis is an autoimmune inflammatory skin disorder with complex physiology.

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Conventional treatments for psoriasis cause severe adverse effects; therefore an unmet need remains for safer and more effective therapies for psoriasis.

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Various drugs that effectively decrease the inflammation and proliferation of skin cells can be repurposed for the management of psoriasis.

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Repurposed drugs provide various incentives to the pharmaceutical industry.

Paclitaxel Inhibits Synoviocyte Migration and Inflammatory Mediator Production in Rheumatoid Arthritis

Activated fibroblast-like synoviocytes (FLSs) play a crucial role in the pathogenesis and progression of rheumatoid arthritis (RA). It is urgent to develop new drugs that can effectively inhibit the abnormal activation of RA-FLS. In our study, the RA-FLS cell line, MH7A, and mice with collagen-induced arthritis (CIA) were used to evaluate the effect of paclitaxel (PTX). Based on the results, PTX inhibited the migration of RA-FLS in a dose-dependent manner and significantly reduced the spontaneous expression of IL-6, IL-8, and RANKL mRNA and TNF-α-induced transcription of the IL-1β, IL-8, MMP-8, and MMP-9 genes. However, PTX had no significant effect on apoptosis in RA-FLS. Mechanistic studies revealed that PTX significantly inhibited the TNF-α-induced phosphorylation of ERK1/2 and JNK in the mitogen-activated protein kinase (MAPK) pathway and suppressed the TNF-α-induced activation of AKT, p70S6K, 4EBP1, and HIF-1α in the AKT/mTOR pathway. Moreover, PTX alleviated synovitis and bone destruction in CIA mice. In conclusion, PTX inhibits the migration and inflammatory mediator production of RA-FLS by targeting the MAPK and AKT/mTOR signaling pathways, which provides an experimental basis for the potential application in the treatment of RA.

Improved biotechnological production of paclitaxel in Taxus media cell cultures by the combined action of coronatine and calix[8]arenes

Paclitaxel (PTX), a widely used anticancer agent, is found in the inner bark of several Taxus species, although at such low levels that its extraction is ecologically unsustainable. Biotechnological platforms based on Taxus sp. cell cultures offer an eco-friendlier approach to PTX production, with yields that can be improved by elicitation. However, the also limited excretion of target compounds from the producer cells to the medium hampers their extraction and purification. In this context, we studied the effect of treating T. media cell cultures with the elicitor coronatine (COR) and calix[8]arenes (CAL), nanoparticles that can host lipophilic compounds within their macrocyclic scaffold. The highest taxane production (103.5 mg.L^-1), achieved after treatment with COR (1 μM) and CAL (10 mg.L^-1), was 15-fold greater than in the control, and PTX represented 82% of the total taxanes analyzed. Expression levels of the flux-limiting PTX biosynthetic genes, BAPT and DBTNBT, increased after the addition of COR, confirming its elicitor action, but not CAL. The CAL treatment significantly enhanced taxane excretion, especially when production levels were increased by COR; 98% of the total taxanes were found in the culture medium after COR + CAL treatment. By forming complexes with PTX, the nanoparticles facilitated its excretion to the medium, and by protecting cells from PTX toxicity, its intra-and extra-cellular degradation may have been avoided. The addition of COR and CAL to T. media cell cultures is therefore a bio-sustainable and economically viable system to improve the yield of this important anticancer compound.

Biotechnological approaches to the production of plant-derived promising anticancer agents: An update and overview

The plant kingdom is a rich source of bioactive compounds, many of which have been used since pre-history for their therapeutic properties to treat a range of illnesses. These metabolites have recently attracted attention to their antineoplastic activities to treat various cancers relying on different mechanisms. Some of these molecules are glycosides, which have proven useful as anti-cancer agents, namely podophyllotoxin (PPT) anaryltetralin lignan or alkaloids. There are three primary forms of alkaloids, such as indole alkaloids (vincristine and vinblastine from Catharanthus roseus), quinoline alkaloid (camptothecin from Camptotheca acuminata), and diterpenoid alkaloid (taxol and it's analogous from Taxus and Corylus species). This review considers various plant biotechnology approaches used to enhance the production of these anticancer molecules in different species. In this regard, many in vitro culture techniques such as stimulation of suspension culture and hairy roots are being used to investigate the effects of plant growth regulators and elicitors on various explants.

A Novel Surfactant-Free O/O Paclitaxel Ointment for the Topical Treatment of Psoriasis

Psoriasis is an autoimmune disorder disease with pink-colored plaques and excessive proliferation which is hard to be cured completely. The study focuses on the anti-psoriatic efficacy of O/O paclitaxel ointment which can promote the assembly of microtubules and lead to death of overproliferation cells of the psoriasis epidermal. A high-speed shearing method was adopted in preparing the ointment, in which propylene carbonate was used as the internal oil phase to solve paclitaxel completely. It was characterized by the appearance, particle size, rheological behavior, and in vitro release. The amount of paclitaxel retained in normal skin and psoriatic skin was 1.00 ± 0.50 versus 1.53 ± 0.48 μg/g for 0.03% PTX ointment, 1.30 ± 0.39 versus 2.77 ± 0.49 μg/g for 0.1% PTX ointment, and 2.22 ± 0.92 versus 6.65 ± 0.87 μg/g for 0.3% PTX ointment, respectively, which implied that paclitaxel could better retain in inflamed skin than in normal skin; also the amount of drug retained in the skin was proportional to drug content. Paclitaxel ointment displayed good topical tolerance after repeated application on normal mice skin. The therapeutic efficacy of paclitaxel ointment was evaluated with an imiquimod-induced psoriatic model. A significant improvement has been shown both in the phenotypic and histopathological features of psoriatic skin treated with the ointment. There was also a significant reduction in the epidermal thickness compared to the imiquimod group. The findings confirm that the O/O PTX ointment without any surfactant appears to be a promising approach for the treatment of psoriasis.

Plant Secondary Metabolites as Anticancer Agents: Successes in Clinical Trials and Therapeutic Application

Cancer is a multistage process resulting in an uncontrolled and abrupt division of cells and is one of the leading causes of mortality. The cases reported and the predictions for the near future are unthinkable. Food and Drug Administration data showed that 40% of the approved molecules are natural compounds or inspired by them, from which, 74% are used in anticancer therapy. In fact, natural products are viewed as more biologically friendly, that is less toxic to normal cells. In this review, the most recent and successful cases of secondary metabolites, including alkaloid, diterpene, triterpene and polyphenolic type compounds, with great anticancer potential are discussed. Focusing on the ones that are in clinical trial development or already used in anticancer therapy, therefore successful cases such as paclitaxel and homoharringtonine (in clinical use), curcumin and ingenol mebutate (in clinical trials) will be addressed. Each compound’s natural source, the most important steps in their discovery, their therapeutic targets, as well as the main structural modifications that can improve anticancer properties will be discussed in order to show the role of plants as a source of effective and safe anticancer drugs.

Dermatological adverse events with taxane chemotherapy

Taxanes (docetaxel and paclitaxel) are among the most commonly prescribed anticancer drugs approved for the treatment of metastatic or locally advanced breast, non-small cell lung, prostate, gastric, head and neck, and ovarian cancers, as well as in the adjuvant setting for operable node-positive breast cancers. Although the true incidence of dermatological adverse events (AEs) in patients receiving taxanes is not known, and has never been prospectively analysed, they clearly represent one of the major AEs associated with these agents. With an increase in the occurrence of cutaneous AEs during treatment with novel targeted and immunological therapies when used in combination with taxanes, a thorough understanding of reactions attributable to this class is imperative. Moreover, identification and management of dermatological AEs is critical for maintaining the quality of life in cancer patients and for minimizing dose modifications of their antineoplastic regimen. This analysis represents a systematic review of the dermatological conditions reported with the use of these drugs, complemented by experience at comprehensive cancer centres. The conditions reported herein include skin, hair, and nail toxicities. Lastly, we describe the dermatological data available for the new, recently FDA-and EMA- approved, solvent-free nab-paclitaxel.

Improving 10-deacetylbaccatin III-10-β-O-acetyltransferase catalytic fitness for Taxol production

The natural concentration of the anticancer drug Taxol is about 0.02% in yew trees, whereas that of its analogue 7-β-xylosyl-10-deacetyltaxol is up to 0.5%. While this compound is not an intermediate in Taxol biosynthetic route, it can be converted into Taxol by de-glycosylation and acetylation. Here, we improve the catalytic efficiency of 10-deacetylbaccatin III-10-O-acetyltransferase (DBAT) of Taxus towards 10-deacetyltaxol, a de-glycosylated derivative of 7-β-xylosyl-10-deacetyltaxol to generate Taxol using mutagenesis. We generate a three-dimensional structure of DBAT and identify its active site using alanine scanning and design a double DBAT mutant (DBAT^G38R/F301V) with a catalytic efficiency approximately six times higher than that of the wild-type. We combine this mutant with a β-xylosidase to obtain an in vitro one-pot conversion of 7-β-xylosyl-10-deacetyltaxol to Taxol yielding 0.64 mg ml⁻¹ Taxol in 50 ml at 15 h. This approach represents a promising environmentally friendly alternative for Taxol production from an abundant analogue.

Taxol is a widely used anticancer drug that is found in very low amounts in the bark of Taxus plants. Here, the authors improve the catalytic fitness of DBAT, an enzyme that catalyses the conversion of tree by products into taxol, enabling the design of an in vitro biochemical systems for taxol production.

Psoriasis treatment: Unconventional and non-standard modalities in the era of biologics

Psoriasis is a potentially debilitating inflammatory dermatosis affecting 0.2%-4.8% of the population worldwide causing a significant occupational, personal or psychosocial morbidity to these patients for life. The basic aim of psoriasis therapy is to control the disease to maximum possible extent and improve the patient’s quality of life. Management of triggers for flare-ups, lifestyle modifications, and dietary supplements are often recommended. Intermittent or rotational therapy with frequent alterations in treatment options is usually needed to reduce toxicity of anti-psoriatic drugs in the absence of safer alternatives. Currently, several biological agents categorized as either T-cell targeted (e.g., Alefacept, Efalizumab) or cytokine modulating (e.g., Adalimumab, Infliximab, Etanercept) are available for treating severe psoriasis. However, their high cost is often precluding for most patients. The usefulness of systemic (methotrexate, cyclosporine, acitretin or several other therapeutic agents) or topical (tar, anthralin, corticosteroids or calcipotriol ointments, phototherapy with or without psoralens) therapies has been well established for the management of psoriasis. The literature is also replete with benefits of less used non-standard and unconventional treatment modalities (hydroxycarbamide, azathioprine, leflunomide, mycophenolate mofetil, isotretinoin, fumarates, topical calcineurin inhibitors, peroxisome proliferator-activated receptors agonists, statins, sulfasalazine, pentoxifylline, colchicine, grenz ray therapy, excimer laser, climatotherapy and balneophototherapy, peritoneal dialysis, tonsillectomy, ichthyotherapy, etc.). These can be used alternatively to treat psoriasis patients who have mild/minimal lesions, are intolerant to conventional drugs, have developed side effects or achieved recommended cumulative dose, where comorbidities pose unusual therapeutic challenges, or may be as intermittent, rotational or combination treatment alternatives.

Advances in exploring alternative Taxol sources

The protection and sustainable utilization of natural resources are among the most pressing global problems of the 21st century.

Nanotechnological approaches for the effective management of psoriasis

Psoriasis is a chronic disorder with erythematous scaly patches, which typically affects the exposed surfaces of the body and scalp. Various factors such as bacterial infection, genetic and environmental factors, and immune disorders play an important role in causing psoriasis. Different types of psoriasis can be observed, such as guttate psoriasis, inverse psoriasis, pustular psoriasis, and psoriatic arthritis. Various ancient, topical, and systemic approaches have been used to control the disease, but have failed to achieve a complete reduction of the disease, besides causing toxic effects. Therefore, our main aim in this review article is to introduce the different advanced nanotechnological approaches for effective treatment of psoriasis.

Novel factors in the pathogenesis of psoriasis and potential drug candidates are found with systems biology approach

Psoriasis is a multifactorial inflammatory skin disease characterized by increased proliferation of keratinocytes, activation of immune cells and susceptibility to metabolic syndrome. Systems biology approach makes it possible to reveal novel important factors in the pathogenesis of the disease. Protein-protein, protein-DNA, merged (containing both protein-protein and protein-DNA interactions) and chemical-protein interaction networks were constructed consisting of differentially expressed genes (DEG) between lesional and non-lesional skin samples of psoriatic patients and/or the encoded proteins. DEGs were determined by microarray meta-analysis using MetaOMICS package. We used STRING for protein-protein, CisRED for protein-DNA and STITCH for chemical-protein interaction network construction. General network-, cluster- and motif-analysis were carried out in each network. Many DEG-coded proteins (CCNA2, FYN, PIK3R1, CTGF, F3) and transcription factors (AR, TFDP1, MEF2A, MECOM) were identified as central nodes, suggesting their potential role in psoriasis pathogenesis. CCNA2, TFDP1 and MECOM might play role in the hyperproliferation of keratinocytes, whereas FYN may be involved in the disturbed immunity in psoriasis. AR can be an important link between inflammation and insulin resistance, while MEF2A has role in insulin signaling. A controller sub-network was constructed from interlinked positive feedback loops that with the capability to maintain psoriatic lesional phenotype. Analysis of chemical-protein interaction networks detected 34 drugs with previously confirmed disease-modifying effects, 23 drugs with some experimental evidences, and 21 drugs with case reports suggesting their positive or negative effects. In addition, 99 unpublished drug candidates were also found, that might serve future treatments for psoriasis.

Microtubule-stabilizing agents delay the onset of EAE through inhibition of migration

We have shown previously that microtubule-stabilizing agents (MSA), a class of anti-proliferative compounds, can delay disease onset and reduce cumulative disease in an experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). To explore how MSA could alter EAE disease processes, we compared the effect of administering MSA before or after peak antigen-specific proliferation and found that treatment before proliferation completely inhibited antigen-specific responses in the spleen; whereas administration of an MSA such as paclitaxel or docetaxel after peak proliferation did not. Despite the presence of antigen-specific responses in mice treated at the later time point, both treatment periods resulted in similar protection against EAE, suggesting that the protective effect of MSA in EAE could not be solely attributed to anti-proliferative activity. Instead, using in vivo migration assays, it was shown that MSA inhibit immune cell infiltration into the central nervous system (CNS). Furthermore, we found that the efficacy of an MSA could be enhanced by administering low doses of two different MSA together, such as peloruside A and ixabepilone, indicating that these MSA synergize in vivo to suppress disease. Taken together, these data suggest that MSA can suppress EAE by at least two distinct mechanisms of action--prevention of proliferation and inhibition of migration into the CNS. Finally, we have shown that a combination treatment with synergizing MSA may provide enhanced protection at lower therapeutic doses.

Paclitaxel Nano-Delivery Systems: A Comprehensive Review

Paclitaxel is one of the most effective chemotherapeutic drugs ever developed and is active against a broad range of cancers, such as lung, ovarian, and breast cancers. Due to its low water solubility, paclitaxel is formulated in a mixture of Cremophor EL and dehydrated ethanol (50:50, v/v) a combination known as Taxol. However, Taxol has some severe side effects related to Cremophor EL and ethanol. Therefore, there is an urgent need for the development of alternative Taxol formulations. The encapsulation of paclitaxel in biodegradable and non-toxic nano-delivery systems can protect the drug from degradation during circulation and in-turn protect the body from toxic side effects of the drug thereby lowering its toxicity, increasing its circulation half-life, exhibiting improved pharmacokinetic profiles, and demonstrating better patient compliance. Also, nanoparticle-based delivery systems can take advantage of the enhanced permeability and retention (EPR) effect for passive tumor targeting, therefore, they are promising carriers to improve the therapeutic index and decrease the side effects of paclitaxel. To date, paclitaxel albumin-bound nanoparticles (Abraxane®) have been approved by the FDA for the treatment of metastatic breast cancer and non-small cell lung cancer (NSCLC). In addition, there are a number of novel paclitaxel nanoparticle formulations in clinical trials. In this comprehensive review, several types of developed paclitaxel nano-delivery systems will be covered and discussed, such as polymeric nanoparticles, lipid-based formulations, polymer conjugates, inorganic nanoparticles, carbon nanotubes, nanocrystals, and cyclodextrin nanoparticles.

Inhibition of peptidyl-arginine deiminases reverses protein-hypercitrullination and disease in mouse models of multiple sclerosis

Multiple sclerosis (MS) is the most common CNS-demyelinating disease of humans, showing clinical and pathological heterogeneity and a general resistance to therapy. We first discovered that abnormal myelin hypercitrullination, even in normal-appearing white matter, by peptidylarginine deiminases (PADs) correlates strongly with disease severity and might have an important role in MS progression. Hypercitrullination is known to promote focal demyelination through reduced myelin compaction. Here we report that 2-chloroacetamidine (2CA), a small-molecule, PAD active-site inhibitor, dramatically attenuates disease at any stage in independent neurodegenerative as well as autoimmune MS mouse models. 2CA reduced PAD activity and protein citrullination to pre-disease status. In the autoimmune models, disease induction uniformly induced spontaneous hypercitrullination with citrulline+ epitopes targeted frequently. 2CA rapidly suppressed T cell autoreactivity, clearing brain and spinal cord infiltrates, through selective removal of newly activated T cells. 2CA essentially prevented disease when administered before disease onset or before autoimmune induction, making hypercitrullination, and specifically PAD enzymes, a therapeutic target in MS models and thus possibly in MS.

Development of paclitaxel-TyroSpheres for topical skin treatment

A potential topical psoriasis therapy has been developed consisting of tyrosine-derived nanospheres (TyroSpheres) with encapsulated anti-proliferative paclitaxel. TyroSpheres provide enhancement of paclitaxel solubility (almost 4000 times greater than PBS) by effective encapsulation and enable sustained, dose-controlled release over 72 h under conditions mimicking skin permeation. TyroSpheres offer potential in the treatment of psoriasis, a disease resulting from over-proliferation of keratinocytes in the basal layer of the epidermis, by (a) enabling delivery of paclitaxel into the epidermis at concentrations >100 ng/cm(2) of skin surface area and (b) enhancing the cytotoxicity of loaded paclitaxel to human keratinocytes (IC(50) of paclitaxel-TyroSpheres was approximately 45% lower than that of free paclitaxel). TyroSpheres were incorporated into a gel-like viscous formulation to improve their flow characteristics with no impact on homogeneity, release or skin distribution of the payload. The findings reported here confirm that the TyroSpheres provide a platform for paclitaxel topical administration allowing skin drug localization and minimal systemic escape.

Psoriasis

Psoriasis is a common relapsing and remitting immune-mediated inflammatory disease that affects the skin and joints. This review focuses on current immunogenetic concepts, key cellular players, and axes of cytokines that are thought to contribute to disease pathogenesis. We highlight potential therapeutic targets and give an overview of the currently used immune-targeted therapies.

Modulation of protein-protein interactions as a therapeutic strategy for the treatment of neurodegenerative tauopathies

The recognition that malfunction of the microtubule (MT) associated protein tau is likely to play a defining role in the onset and/or progression of a number of neurodegenerative diseases, including Alzheimer's disease, has resulted in the initiation of drug discovery programs that target this protein. Tau is an endogenous MT-stabilizing agent that is highly expressed in the axons of neurons. The MT-stabilizing function of tau is essential for the axonal transport of proteins, neurotransmitters and other cellular constituents. Under pathological conditions, tau misfolding and aggregation results in axonal transport deficits that appear to have deleterious consequences for the affected neurons, leading to synapse dysfunction and, ultimately, neuronal loss. This review focuses on both progress and unresolved issues surrounding the development of novel therapeutics for the treatment of neurodegenerative tauopathies, which are based on (A) MT-stabilizing agents to compensate for the loss of normal tau function, and (B) small molecule inhibitors of tau aggregation.

Molecular pathophysiology of psoriasis and molecular targets of antipsoriatic therapy

Psoriasis is a chronic inflammatory skin disease characterised by elevated red scaly plaques on specific body sites. Histologically, the plaques are defined by epidermal hyperplasia, epidermal and dermal infiltration by leukocytes, and changes in the dermal microvasculature. Differentiation and activation are disturbed in lesional psoriatic keratinocytes, and the pool of proliferating keratinocytes is increased, which is accompanied by enhanced production of proinflammatory cytokines, adhesion molecules and antimicrobial peptides. These changes in psoriatic keratinocytes are caused by altered expression of genes associated with epidermal differentiation, and by activation of signalling pathways involving signal transducer and activator of transcription 3 (STAT3), type I interferon (IFN) and mitogen-activated protein kinase (MAPK). The number of T cells, and myeloid and plasmacytoid dendritic cells (DCs) is markedly increased in psoriatic lesions. Myeloid DCs produce interleukin (IL)-23, tumour necrosis factor (TNF)-alpha and inducible nitric oxide synthase (iNOS), which are crucial cytokines in the pathogenesis of psoriasis. IL-23 stimulates the secretion of IL-22 by T helper 17 cells, and IL-22 induces epidermal hyperplasia. The crosstalk between keratinocytes and leukocytes via their proinflammatory cytokines creates the vicious circle of chronic skin inflammation seen in psoriasis. This suggests that optimal treatment of psoriasis needs to target pathogenic pathways in both leukocytes and keratinocytes.

Nonstandard and off-label therapies for psoriasis

Although most psoriasis patients respond to standard therapies, many circumstances warrant the use of nonstandard or off-label treatments. For instance, patients with treatment-resistant psoriasis or those who have had multiple adverse effects to other therapies may be good candidates for off-label treatments. Similarly, patients with unusual and hard-to-treat forms of psoriasis such as pustular psoriasis and palmoplantar psoriasis or specific comorbidities may benefit from certain nonstandard therapies. Drugs that may be used as alternatives to standard therapies include mycophenolate mofetil, tacrolimus or pimecrolimus, isotretinoin, colchicine, sulfasalazine, paclitaxel, dapsone, azathioprine, and hydroxyurea. Other unconventional therapies include climatotherapy at the Dead Sea and grenz ray therapy.

Kinetics of human peptidylarginine deiminase 2 (hPAD2) — Reduction of Ca2+ dependence by phospholipids and assessment of proposed inhibition by paclitaxel side chains

Multiple sclerosis is a complex human neurodegenerative disease, characterized by the active destruction of the insulating myelin sheath around the axons in the central nervous system. The physical deterioration of myelin is mediated by hyperdeimination of myelin basic and other proteins, catalysed by the Ca2+-dependent enzyme peptidylarginine deiminase 2 (PAD2). Thus, inhibition of PAD2 may be of value in treatment of this disease. Here, we have first characterized the in vitro kinetic properties of the human peptidylarginine deiminase isoform 2 (hPAD2). Phosphatidylserine and phosphatidylcholine reduced its Ca2+ dependence by almost twofold. Second, we have explored the putative inhibitory action of the methyl ester side chain of paclitaxel (TSME), which shares structural features with a synthetic PAD substrate, viz., the benzoyl-l-arginine ethyl ester (BAEE). Using the known crystallographic structure of the homologous enzyme hPAD4 and in silico molecular docking, we have shown that TSME interacted strongly with the catalytic site, albeit with a 100-fold lower affinity than BAEE. Despite paclitaxel having previously been shown to inhibit hPAD2 in vitro, the side chain of paclitaxel alone did not inhibit this enzyme’s activity.

Paclitaxel C-10 carbamates: potential candidates for the treatment of neurodegenerative tauopathies

A series of paclitaxel C-10 carbamates was synthesized and evaluated in a bi-directional permeability assay in comparison with paclitaxel and the blood-brain barrier-permeable C-10 ester derivative, TX-67. A number of the carbamates were found not to be substrates for Pgp. Moreover, when tested for Pgp-inhibitory potential, representative compounds proved to be devoid of Pgp interactions. Side-by-side comparison between TX-67 and the corresponding C-10 carbamate, CNDR-3, revealed a significantly longer half-life for CNDR-3 in both mouse and human plasma, suggesting that this class of derivatives is appropriate for further in vivo evaluation.

Emerging drugs for psoriasis

Psoriasis is a chronic immune-mediated inflammatory skin disease characterised by abnormal keratinocyte differentiation and proliferation. The immunopathogenesis is complex and novel evidence shows the involvement of both innate and adaptive immune response. Type 1 T cells and their effector cytokines play a pivotal role. Several drugs under preclinical and clinical development for psoriasis are directed against the immune response, targeting activation or proliferation of T cells, their trafficking and skin-homing, or effector cytokines. Among these, great attention has been given to TNF-alpha, following the demonstration of effectiveness of anti-TNF-alpha biologicals, and to IFN-gamma inducers. Another appealing approach concerns drugs capable of inducing immunological tolerance. Progress made in the recognition of intracellular events has prompted the development of small molecules and oligonucleotides that can inhibit specific molecular targets. There is, however, a plethora of other emerging drugs, clearly suggestive of the current interest for psoriasis, which are briefly described in this paper.

Peptidylarginine deiminases and deimination in biology and pathology: relevance to skin homeostasis

Deimination corresponds to the transformation of arginine residues within a peptide sequence into citrulline residues. Catalyzed by peptidylarginine deiminases, it decreases the net positive charge of proteins, alters intra and intermolecular ionic interactions and probably the folding of target proteins. Deimination has recently been implicated in several physiological and pathological processes. Here, we describe the enzymes involved in this post-translational modification, focusing on their expression, location and roles in skin, as well as their known protein substrates in the epidermis and hair follicles. We discuss also the potential involvement of deimination in human diseases including cutaneous disorders.

Citrullination: a posttranslational modification in health and disease

Posttranslational modifications are chemical changes to proteins that take place after synthesis. One such modification, peptidylarginine to peptidylcitrulline conversion, catalysed by peptidylarginine deiminases, has recently received significant interest in biomedicine. Introduction of citrulline dramatically changes the structure and function of proteins. It has been implicated in several physiological and pathological processes. Physiological processes include epithelial terminal differentiation, gene expression regulation, and apoptosis. Rheumatoid arthritis, multiple sclerosis, and Alzheimer's disease are examples of human diseases where protein citrullination involvement has been demonstrated. In this review, we discuss our current understanding on the importance of protein deimination in these processes. We describe the enzymes catalyzing the reaction, as well as their known protein substrates. We review the citrullinated peptide epitopes that are proposed as disease markers, specifically recognized in certain human autoimmune disorders. The potential autopathogenic role of citrullinated epitopes is also discussed.