Advances in the therapeutic use of mammalian target of rapamycin (mTOR) inhibitors in dermatology

Two-electron oxidized polyphenol chemistry-inspired superhydrophilic drug-carrying coatings for the construction of multifunctional nasolacrimal duct stents

Nasolacrimal duct obstruction due to infection, inflammation, or excessive fibroblast proliferation may result in persistent tearing, intraocular inflammation, or even blindness. In this study, surface engineering techniques are applied to nasolacrimal duct stents for the first time. Based on the functioning of marine mussels, "one-pot" and "stepwise" methods were employed to construct a novel multifunctional superhydrophilic PDA/RAP coating using dopamine and rapamycin. Micron-sized rapamycin crystals combined with nano-sized polydopamine particles form a micro-nano topographical structure. Therefore, acting synergistically with in situ-generated hydrophilic groups (amino, carboxyl, and phenolic hydroxyl), they impart excellent and long-lasting superhydrophilicity to the nasolacrimal duct stent. The PDA/RAP coating effectively maintained the stability of the initial microenvironment during stent implantation by inhibiting the onset of acute inflammation and infection during the early stages of implantation. Meanwhile, the rapamycin crystals, supported by the superhydrophilic platform, exhibited a sustained-release capability that helped them to better exert their anti-inflammatory, antibacterial, and anti-fibroblast proliferative properties, ensuring conducive conditions for the rapid repair of nasolacrimal duct epithelial cells, verified by a series of experiments. In conclusion, the PDA/RAP hydrophilic coating has anti-inflammatory, antifibrotic, antibacterial, and antithrombotic properties, offering a new strategy to address restenosis following clinical nasolacrimal duct stent implantation.

Oral sirolimus for the treatment of juvenile xanthogranuloma: Report of two pediatric cases

Juvenile xanthogranuloma (JXG) with extensive cutaneous or visceral organ involvement is often associated with high morbidity and treatment commonly involves surgical excision, radiotherapy, systemic steroids, or chemotherapy. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is an oral antitumor and immunosuppressive therapy used to treat various neoplastic disorders, including histiocytic disorders. We report two pediatric cases of JXG successfully treated with oral sirolimus monotherapy, and postulate that sirolimus may induce rapid disease resolution and long-term remission for patients with both skin-limited and multisystemic JXG. Our findings warrant further investigation of the relationship between the mTOR pathway and JXG.

Posttranslational modifications of keratins and their associated proteins as therapeutic targets in keratin diseases

The keratin cytoskeleton protects epithelia against mechanical, nonmechanical, and physical stresses, and participates in multiple signaling pathways that regulate cell integrity and resilience. Keratin gene mutations cause multiple rare monoallelic epithelial diseases termed keratinopathies, including the skin diseases Epidermolysis Bullosa Simplex (EBS) and Pachyonychia Congenita (PC), with limited available therapies. The disease-related keratin mutations trigger posttranslational modifications (PTMs) in keratins and their associated proteins that can aggravate the disease. Recent findings of drug high-throughput screening have led to the identification of compounds that may be repurposed, since they are used for other human diseases, to treat keratinopathies. These drugs target unique PTM pathways and sites, including phosphorylation and acetylation of keratins and their associated proteins, and have shed insights into keratin regulation and interactions. They also offer the prospect of testing the use of drug mixtures, with the long view of possible beneficial human use coupled with increased efficacy and lower side effects.

Bio-evaluation of Untapped Alkaloids from Vinca minor Enriched by Methyl-jasmonate-induced Stress: an Integrated Approach

The low amount of metabolites isolated from natural products is one of the challenges preventing their biological evaluation. The modulation of biosynthetic pathways by stimulating stress-induced responses in plants was proven to be a valuable tool for diversification of already known natural products. Recently, we reported the dramatic effect of methyl jasmonate (MeJA) on Vinca minor alkaloids distribution. In this study, three compounds identified as 9-methoxyvincamine, minovincinine, and minovincine are successfully isolated in good yield and subjected to several bioassays based on a network pharmacology study. The extracts and isolated compounds show weak to moderate antimicrobial and cytotoxic activities. Also, they are found to significantly promote wound healing in scratch assay, and transforming growth factor-β (TGF-β) modulation is suggested to be the potential pathway based on bioinformatic analysis. Hence, Western blotting is used to assess the expression of several markers related to this pathway and wound healing. The extracts and isolated compounds are able to increase the expression of Smad3 and Phosphatidylinositol-3-kinase (PI3K), while downregulating the levels of cyclin D1 and the mammalian target of rapamycin (mTOR) except for minovincine, which increases the mTOR expression, inferring that it might act through a different mechanism. Molecular docking is used to give insights on the ability of isolated compounds to bind with different active sites in mTOR. Collectively, the integrated phytochemical, in silico, and molecular biology approach reveal that V. minor and its metabolite could be repurposed for the management of dermatological disorders where these markers are dysregulated, which opens the gate to develop new therapeutics in the future.

EGCG identified as an autophagy inducer for rosacea therapy

Background: Rosacea is a common facial skin inflammatory disease featured by hyperactivation of mTORC1 signaling in the epidermis. Due to unclear pathogenesis, the effective treatment options for rosacea remain limited. Methods: Weighted gene co-expression network analysis (WGCNA) analyzed the relationship between epidermis autophagy and mTOR pathways in rosacea, and further demonstrated it through immunofluorescence and qPCR analysis. A potential therapeutic agent for rosacea was predicted based on the key genes of the WGCNA module. In vivo and in vitro experiments were conducted to verify its therapeutic role. Drug-target prediction (TargetNet, Swiss, and Tcmsp) and molecular docking offered potential pharmacological targets. Results: WGCNA showed that epidermis autophagy was related to the activation of mTOR pathways in rosacea. Next, autophagy was downregulated in the epidermis of rosacea, which was regulated by mTOR. In addition, the in vivo experiment demonstrated that autophagy induction could be an effective treatment strategy for rosacea. Subsequently, based on the key genes of the WGCNA module, epigallocatechin-3-gallate (EGCG) was predicted as a potential therapeutic agent for rosacea. Furthermore, the therapeutic role of EGCG on rosacea was confirmed in vivo and in vitro. Finally, drug-target prediction and molecular docking revealed that AKT1/MAPK1/MMP9 could be the pharmacological targets of EGCG in rosacea. Conclusion: Collectively, our findings revealed the vital role of autophagy in rosacea and identified that EGCG, as a therapeutic agent for rosacea, attenuated rosacea-like inflammation via inducing autophagy in keratinocytes.

Topical sirolimus solution for lingual microcystic lymphatic malformations in children and adults (TOPGUN): study protocol for a multicenter, randomized, assessor-blinded, controlled, stepped-wedge clinical trial

Background

Lingual microcystic lymphatic malformations (LMLMs) are rare congenital vascular malformations presenting as clusters of cysts filled with lymph fluid or blood. Even small well-limited lesions can be responsible for a heavy burden, inducing pain, aesthetic prejudice, or oozing, bleeding, infections. The natural history of LMLMs is progressive worsening punctuated by acute flares. Therapeutic options include surgery, laser excision, and radiofrequency ablation but all are potentially detrimental and expose to local relapse. Therefore, the management frequently relies on a “watchful waiting” approach. In complicated LMLMs, treatment with oral sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is often used. Topical applications of sirolimus on the buccal mucosae have been reported in other oral diseases with good tolerance and none to slight detectable blood sirolimus concentrations. We aim to evaluate the efficacy and safety of a 1 mg/mL sirolimus solution applied once daily on LMLM of any stage in children and adults after 4, 8, 12, 16, 20, and 24 weeks of treatment compared to usual care (no treatment).

Methods

This is a randomized, multicentric study using an individually randomized stepped-wedge design over 24 weeks to evaluate topical application of a 1 mg/mL sirolimus solution once daily, on LMLM, versus usual care (no treatment), the control condition. Participants begin with an observational period and later switch to the intervention at a randomized time (week 0, 4, 8, or 12). Visits occur every 4 weeks, either in the study center or by teleconsulting. The primary outcome will be the evaluation of global severity of the LMLM on monthly standardized photographs by 3 independent blinded experts using the physical global assessment (PGA) 0 to 5 scale. Secondary outcomes will include lesion size measurement and quality of life assessment, investigator, and patient-assessed global disease and specific symptoms (oozing, bleeding, sialorrhea, eating impairment, taste modification, aesthetic impairment, pain, and global discomfort) assessment. A biological monitoring will be performed including residual blood sirolimus concentration and usual laboratory parameters.

Discussion

Given the disappointing state of current treatment options in LMLMs, topical sirolimus could become firstline therapy in treating LMLMs if its efficacy and safety were to be demonstrated.

Trial registration

ClinicalTrials.gov NCT04128722. Registered on 24 September 2019.

EudraCT: EUCTR2019-001530-33-FR

Sponsor (University Hospital Center of Tours – CHRU Tours): DR190041-TOPGUN

French regulatory authorities: ID RCB: 2019-001530-33

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06365-y.

Efficacy and Safety of Topical Mechanistic Target of Rapamycin Inhibitors for Facial Angiofibromas in Patients with Tuberous Sclerosis Complex: A Systematic Review and Network Meta-Analysis

Previous studies have suggested that the topical mechanistic target of rapamycin (mTOR) inhibitors may be effective in treating facial angiofibromas in patients with tuberous sclerosis complex (TSC). Various concentrations of topical sirolimus for TSC have been tested, but their comparative efficacy and safety remained unclear. To assess the effects of topical mTOR inhibitors in treating facial angiofibromas, we conducted a systematic review and network meta-analysis (NMA) and searched MEDLINE, Embase, and Cochrane Library for relevant randomized controlled trials on 14 February 2022. The Cochrane Collaboration tool was used to assess the risk of bias of included trials. Our outcomes were clinical improvement and severe adverse events leading to withdrawal. We included three trials on 261 TSC patients with facial angiofibromas. The NMA found when compared with placebo, facial angiofibromas significantly improved following the application of various concentrations of topical sirolimus (risk ratio being 3.87, 2.70, 4.43, and 3.34 for 0.05%, 0.1%, 0.2%, and 1%, respectively). When compared with placebo, all concentrations of topical sirolimus did not differ in severe adverse events leading to withdrawal. The ranking analysis suggested topical sirolimus 0.2% as the most effective drug. In conclusion, topical sirolimus 0.05–1% are effective and safe in treating facial angiofibromas in patients with TSC, with topical sirolimus 0.2% being the most effective.

Diosmetin Induces Modulation of Igf-1 and Il-6 Levels to Alter Rictor-Akt-PKCα Cascade in Inhibition of Prostate Cancer

Growth signals, which typically originate from the surrounding microenvironment, are important for cells. However, when stimulation by growth factors becomes excessive and exceeds their threshold limit, deleterious effects may ensue. In patients with cancer, maintenance of tumors depends, at least in part, on growth factor stimulation, which can also facilitate cancer progression into advanced stages. This is particularly important when the tumor grows beyond its tissue boundaries or when it invades and colonizes other tissues. These aforementioned malignant events are known to be partly supported by elevated cytokine levels. Among the currently known growth signals, insulin-like growth factor (IGF)-1 and IL-6 have been previously studied for their roles in prostate cancer. Both IGF-1 and IL-6 have been reported to activate the RAPTOR independent companion of MTOR complex 2 (Rictor)/AKT/protein kinase C α (PKCα) signaling pathway as one of their downstream mechanisms. At present, research efforts are mainly focused on the exploration of agents that alter growth factor (such as IGF-1) and cytokine (such as IL-6) signaling for their potential application as therapeutic agents, as both of these have been reported to modulate disease outcome. In the present study, IGF-1 and IL-6 served distinct roles in the androgen responsive LNCaP cell line and in the androgen refractory PC-3 cell line in a dose- and time-dependent manner. Increased phosphorylation of Rictor at the Thr-1135 residue, AKT at the Ser-473 residue and PKCα at the Ser-657 residue were observed after treatment with IGF-1 and IL-6. Subsequently, it was found that diosmetin, a natural plant aglycone, had the potential to modulate the downstream signaling cascade of Rictor/AKT/PKCα to inhibit the progression of prostate cancer. Treatment of LNCaP and PC-3 cells with diosmetin inhibited the phosphorylation of Rictor (Thr-1135), AKT (Ser-473) and PKCα (Ser-657) in a dose-dependent manner. Furthermore, the Bax/Bcl-2 expression ratio was increased in response to diosmetin treatment, which would result in increased apoptosis. Based on these observations, diosmetin may represent a novel therapeutic target for prostate cancer.

Systematic review of sirolimus in dermatological conditions

Sirolimus is a mammalian target of rapamycin inhibitor (mTORI) with anti-proliferative, antiangiogenic and immunosuppressive properties. While approved in Australia as an anti-rejection medication for renal transplant patients, there is mounting evidence regarding the utility of oral and topical sirolimus in treating a plethora of dermatological conditions or conditions with cutaneous manifestations. Our aim was to present an overview of the evidence for current usage and breadth of the application of sirolimus in dermatology. We carried out a systematic review of all the literature published up to 31 August 2019 on oral and topical sirolimus with respect to dermatological conditions or conditions otherwise relevant to dermatology. While 3368 papers were initially produced in our search, 238 papers met our inclusion criteria and were examined in our review. The conditions examined were categorised into genodermatoses (9 conditions), infection (1 condition), inflammatory/autoimmune (10 conditions), neoplasm (3 conditions) and vascular (17 conditions). We extracted data on first author, publication year, journal, characteristics of the study and study patients, condition, drug modalities, drug efficacy, side effects, blood level of mTORI, co-interventions and follow-up. While there is level 1 evidence for the efficacy of sirolimus in conditions such as tuberous sclerosis complex (TSC) and GVHD prophylaxis, for many other conditions, the evidence is limited to level 4 evidence. Regarding oral systemic therapy, dosing regimens varied with the most common for children 0.8mg/m² twice daily and for adults 1 mg twice daily. Doses were often adjusted to reach a typical trough level of between 5 and 15 ng/mL, though targets often varied. In the overall majority of cases, side effects were minimal or tolerable, including mucositis, cytopenias, lipid abnormalities and nausea/vomiting, and only a few cases had to stop due to adverse effects. Regarding topical therapy, concentration of formulations varied from 0.1% to 1% and were compounded into creams, ointments or gels and administered typically once or twice per day. The most common side effect was skin irritation. There were a number of limitations to our study. In particular, many of the published studies were case reports or case series with no comparator arm, leading to susceptibility of bias in conclusions drawn, in particular a high likelihood of publication bias. Given the heterogeneity amongst studies, comparisons or aggregation of results was difficult. There continues to be growing use of oral and topical sirolimus in dermatological conditions. It provides new therapeutic options to patients where previous therapies have either failed or are limited due to toxicity. However, further studies are warranted.

A patent review of mTOR inhibitors for cancer therapy (2011-2020)

INTRODUCTION

The mammalian target of rapamycin (mTOR) kinase is a central component in the PI3K/Akt/mTOR pathway and plays a crucial role in tumor biology, making it one appealing therapeutic target. In the past decade, the mTORi (mTOR inhibitor) development field has made great progress, with more agents entering key trials and the proposal of third-generation mTORi concept. Yet to achieve significant clinical success, combined efforts from multiple disciplines are ever needed.

AREAS COVERED

This review focuses on the progress of mTORi development with anticancer potential from the perspective of the patent literature proposed between 2011 and 2020.

EXPERT OPINION

The highly complex regulatory mechanism network of mTOR proposes huge challenges to the development of clinically efficient mTORis. While in-depth biological research and fundamental medchemistry research are of importance to provide guidelines for improving mTORis, new technologies to pre-diagnose applicable populations is another key to provide precise personal cancer treatment. New mTOR agents are ever needed to tackle the common problems of side effects and drug resistance.

The Use of Sirolimus for Treatment of Orbital Lymphatic Malformations: A Systematic Review

PURPOSE

Orbital lymphatic malformations are rare congenital choristomas associated with pain, proptosis, exposure keratopathy, and vision loss. Current treatments of surgery, drainage, and sclerotherapy may have adverse effects including risk of damage to surrounding structures, swelling, and malformation persistence or recrudescence. Sirolimus, which inhibits mammalian target of rapamycin, a regulator of cell growth and vascular endothelial growth factor expression, has successfully treated systemic vascular malformations. However, its efficacy and safety have not yet been well established for orbital lymphatic malformations.

METHODS

Systematic review and analysis of relevant published literature were performed. PubMed, Embase, and World of Science searches were conducted for studies involving sirolimus treatment of orbital lymphatic malformations through July 2019.

RESULTS

Nine case series and reports with 10 total patients who received sirolimus for treatment of orbital lymphatic malformations were included. The age at sirolimus initiation ranged from 1 week to 23 years. The malformation was lymphatic in 6 patients, lymphaticovenous in 3 patients, and lymphatic-arteriovenous in 1 patient. Six patients underwent ineffective prior therapy including sclerotherapy, surgery, or medical therapy. Initial sirolimus dosage ranged from 0.05 mg/kg twice a day to 1 mg twice a day, and duration ranged from 6 months to 53 months. Seven patients had partial response, and 3 patients, all of whom had a microcystic malformation component, experienced complete response. Adverse effects included mild reversible leukopenia, hypertriglyceridemia, hypercholesterolemia, and transaminitis with adverse effects denied or not specified for 6 patients.

CONCLUSIONS

Sirolimus may be a safe and effective treatment for orbital lymphatic malformations, especially microcystic malformations.

Targeted Inhibition of the Epidermal Growth Factor Receptor and Mammalian Target of Rapamycin Signaling Pathways in Olmsted Syndrome

Importance

Olmsted syndrome is a rare and disabling genodermatosis for which no successful treatment is currently available.

Objective

To evaluate the clinical response to the mammalian target of rapamycin (mTOR) inhibitor sirolimus and/or the epidermal growth factor receptor (EGFR) inhibitor erlotinib among patients with Olmsted syndrome.

Design, Setting, and Participants

This case series focused on 4 children with treatment-refractory Olmsted syndrome. These children received treatments (initiated in 2017 and 2018) at the outpatient dermatology clinic at the Children's Hospital of Wisconsin in Milwaukee, Wisconsin; Children's National Hospital in Washington, DC; and Hospital Infantil Pequeno Príncipe, Curitiba in Paraná, Brazil.

Exposures

Immunohistochemical analyses for mTOR and EGFR activation were performed on skin biopsy specimens from 2 patients. Oral sirolimus was administered to these 2 patients at a dosage of 0.8 mg/m2 twice daily, titrated to a goal trough whole-blood concentration of 10 to 15 ng/mL. Erlotinib was administered to all 4 patients at a dosage of 2 mg/kg/d.

Main Outcomes and Measures

Clinical responses were assessed with visual analog scales for pruritus and pain and/or the Children's Dermatology Life Quality Index. Adverse effects were monitored throughout treatment.

Results

Four patients (mean [SD] age, 7 [6] years; 2 boys and 2 girls) were analyzed. Lesional skin immunostaining showed increased phosphorylated ribosomal protein S6 (RPS6) and phosphorylated EGFR staining in the epidermis, indicating enhanced mTOR and EGFR signaling activation. Patients 1 and 2 were initially treated with sirolimus, displaying substantial clinical improvement in erythema and periorificial hyperkeratosis afterward. When switched to erlotinib, these patients showed substantial palmoplantar keratoderma (PPK) improvement. Patients 3 and 4 were treated with erlotinib only and later showed rapid and near complete resolution of PPK and substantial improvement in Children's Dermatology Life Quality Index scores. All 4 patients had sustained improvements in pruritus and pain. No severe adverse effects were reported.

Conclusions and Relevance

This study's findings suggest that the EGFR-mTOR cascade may play a substantial role in the pathophysiological process of Olmsted syndrome and may serve as a major therapeutic target. Oral sirolimus and erlotinib may be a promising, life-altering treatment for pediatric patients with Olmsted syndrome.

Topical rapamycin versus betamethasone dipropionate ointment for treating oral erosive lichen planus: a randomized, double-blind, controlled study

BACKGROUND

Although superpotent topical corticosteroids are the first-line treatment for oral erosive lichen planus (OELP), topical rapamycin was found efficient in a previous case series.

OBJECTIVES

To compare the efficacy and safety of topical rapamycin and betamethasone dipropionate ointment for OELP in a randomized, double-blind trial.

METHODS

Patients were randomized to receive treatment with betamethasone dipropionate ointment 0.05% in Orabase^® or topical rapamycin solution (1 mg/mL) on lesions twice daily for 3 months, followed by 3 months of observation. The primary outcome was clinical remission after 3 months of treatment. Secondary outcomes were clinical remission after 1 and 2 months, reduced oral pain and reduced impact on food intake after 3 months, clinical recurrence after treatment withdrawal, and adverse events.

RESULTS

During a 4-year period, 76 patients were randomized and 75 received treatment (rapamycin, n = 39; betamethasone, n = 36). At 3 months, 39.4% of patients with betamethasone and 27.3% with rapamycin showed clinical remission (odds ratio 0.68, 95% CI [0.24; 1.89]; P = 0.46). Rates of remission after 1 and 2 months, reduction in pain and impact on food intake after 3 months, were higher with betamethasone than rapamycin. Recurrence of oral erosions was similar between groups. Adverse events occurred in 43.6% of patients with rapamycin (mostly burning sensation, impaired taste) and 27.8% with betamethasone (mostly oral candidiasis).

CONCLUSION

Although the study was limited by insufficient recruitment, we did not find any superiority of topical rapamycin over betamethasone dipropionate ointment for OELP. Given the rapid remission and pain improvement in the betamethasone group, it appears that superpotent topical corticosteroids should remain the first-line treatment for OELP.

Transdermal delivery of rapamycin with poor water-solubility by dissolving polymeric microneedles for anti-angiogenesis

Angiogenesis plays an important role in the occurrence and development of skin tumors and vascular anomalies (VAs). Many drugs have been adopted for the inhibition of angiogenesis, among which rapamycin (RAPA) possesses good application prospects. However, the clinical potential of RAPA for VAs is limited by its poor solubility, low bioavailability, and high cytotoxicity. To extend its application prospect for VAs treatment, in this study, we develop RAPA-loaded dissolving polymeric microneedles (RAPA DMNs) made of polyvinylpyrrolidone (PVP) due to its excellent solubilizing ability. RAPA DMNs are shown to have sufficient mechanical strength to overcome the skin barrier of the stratum corneum and could deliver RAPA to a depth of 200 μm. The microneedle shafts completely dissolve and 80% of the drug could be released within 10 min after insertion ex vivo. The DMNs-penetrated mice skin could repair itself within 4 h after the application of RAPA DMNs. RAPA DMNs also show good anti-angiogenic effect by inhibiting the growth of human umbilical vein endothelial cells (HUVECs) and decreasing the secretion of vascular endothelial growth factor (VEGF). Therefore, RAPA DMNs promisingly provide a safe and efficient approach for VAs treatment.

Successful Medical Management of Life-threatening Hepatic Hemangioma in Neonates

Hepatic hemangioma (HH) is a common asymptomatic, self-limiting benign vascular tumor of the liver in neonates. Although complicated HHs are rare, they have significant risks of morbidity and mortality, especially during the perinatal period. Because of the high risks of complications from surgical interventions, there is an unmet need for effective medical therapy. We report 2 neonates with life-threatening HH who were evaluated for a liver transplant before being treated successfully with combined medical therapy, which included sirolimus, corticosteroids, and propranolol.

PI3K inhibitors protect against glucocorticoid-induced skin atrophy

Background

Skin atrophy is a major adverse effect of topical glucocorticoids. We recently reported that REDD1 (regulated in development and DNA damage 1) and FKBP51 (FK506 binding protein 5), negative regulators of mTOR/Akt signaling, are induced by glucocorticoids in mouse and human skin and are central drivers of steroid skin atrophy. Thus, we hypothesized that REDD1/FKBP51 inhibitors could protect skin against catabolic effects of glucocorticoids.

Methods

Using drug repurposing approach, we screened LINCS library (http://lincsproject.org/LINCS/) to identify repressors of REDD1/FKBP51 expression. Candidate compounds were tested for their ability to inhibit glucocorticoid-induced REDD1/FKBP51 expression in human primary/immortalized keratinocytes and in mouse skin. Reporter gene expression, microarray, and chromatin immunoprecipitation were employed to evaluate effect of these inhibitors on the glucocorticoid receptor (GR) signaling.

Findings

Bioinformatics analysis unexpectedly identified phosphoinositide-3-kinase (PI3K)/mTOR/Akt inhibitors as a pharmacological class of REDD1/FKBP51 repressors. Selected PI3K/mTOR/Akt inhibitors-Wortmannin (WM), LY294002, AZD8055, and two others indeed blocked REDD1/FKBP51expression in human keratinocytes. PI3K/mTOR/Akt inhibitors also modified global effect of glucocorticoids on trascriptome, shifting it towards therapeutically important transrepression; negatively impacted GR phosphorylation; nuclear translocation; and GR loading on REDD1/FKBP51 gene promoters. Further, topical application of LY294002 together with glucocorticoid fluocinolone acetonide (FA) protected mice against FA-induced proliferative block and skin atrophy but did not alter the anti-inflammatory activity of FA in ear edema test.

Interpretation

Our results built a strong foundation for development of safer GR-targeted therapies for inflammatory skin diseases using combination of glucocorticoids with PI3K/mTOR/Akt inhibitors.

Fund

Work is supported by NIH grants R01GM112945, R01AI125366, and HESI-THRIVE foundation.

Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients

BACKGROUND

Data on dermatological manifestations of cardiofaciocutaneous syndrome (CFCS) remain heterogeneous and almost without expert dermatological classification.

OBJECTIVES

To describe the dermatological manifestations of CFCS; to compare them with the literature findings; to assess those discriminating CFCS from other RASopathies, including Noonan syndrome (NS) and Costello syndrome (CS); and to test for dermatological phenotype-genotype correlations.

METHODS

We performed a 4-year, large, prospective, multicentric, collaborative dermatological and genetic study.

RESULTS

Forty-five patients were enrolled. Hair abnormalities were ubiquitous, including scarcity or absence of eyebrows and wavy or curly hair in 73% and 69% of patients, respectively. Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50 naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively. Scarcity or absence of eyebrows, association of UO and PPHK, diffuse KP and MMN best differentiated CFCS from NS and CS. Oral acitretin may be highly beneficial for therapeutic management of PPHK, whereas treatment of UO by topical sirolimus 1% failed. No significant dermatological phenotype-genotype correlation was determined.

CONCLUSIONS

A thorough knowledge of CFCS skin manifestations would help in making a positive diagnosis and differentiating CFCS from CS and NS.

Targeting the mTOR pathway in breast cancer

Mechanistic target of rapamycin controls cell growth, metabolism, and aging in response to nutrients, cellular energy stage, and growth factors. In cancers including breast cancer, mechanistic target of rapamycin is frequently upregulated. Blocking mechanistic target of rapamycin with rapamycin, first-generation and second-generation mechanistic target of rapamycin inhibitors, called rapalogs, have shown potent reduction of breast cancer tumor growth in preclinical models and clinical trials. In this review, we summarize the fundamental role of the mechanistic target of rapamycin pathway in driving breast tumors. Moreover, we also review key molecules involved with aberrant mechanistic target of rapamycin pathway activation in breast cancer and current efforts to target these components for therapeutic gain. Further development of predictive biomarkers will be useful in the selection of patients who will benefit from inhibition of the mechanistic target of rapamycin pathway.

Successful Treatment of a Complex Vascular Malformation With Sirolimus and Surgical Resection

Management of complex vascular malformation represents a challenge as it may include a wide variety of options such as embolization, laser therapy, sclerotherapy, and surgical resection but may lead to significant morbidity and is associated with high recurrence rates. In extreme and/or recurrent cases, successful use of sirolimus has been described. We report a case of large unresectable complex venous malformation treated with oral sirolimus for 24 months. Therapy was well tolerated. Patient had substantial improvement in symptoms and shrinkage of the lesion. The Medical Therapy made excision of the malformation possible and patient had a successful surgical procedure. This report provides further evidence that sirolimus should be considered as part of the armamentarium in the management of these rare conditions.

Mosaic Disorders of the PI3K/PTEN/AKT/TSC/mTORC1 Signaling Pathway

Somatic mutations in genes of the PI3K/PTEN/AKT/TSC/mTORC1 signaling pathway cause segmental overgrowth, hamartomas, and malignant tumors. Mosaicism for activating mutations in AKT1 or PIK3CA cause Proteus syndrome and PIK3CA-Related Overgrowth Spectrum, respectively. Postzygotic mutations in PTEN or TSC1/TSC2 cause mosaic forms of PTEN hamartoma tumor syndrome or tuberous sclerosis complex, respectively. Distinct features observed in these mosaic conditions in part reflect differences in embryological timing or tissue type harboring the mutant cells. Deep sequencing of affected tissue is useful for diagnosis. Drugs targeting mTORC1 or other points along this signaling pathway are in clinical trials to treat these disorders.

Pleurotus nebrodensis polysaccharide(PN50G) evokes A549 cell apoptosis by the ROS/AMPK/PI3K/AKT/mTOR pathway to suppress tumor growth

Since the strong antineoplastic potential against A549 cells of Pleurotus nebrodensis polysaccharide (PN50G) in vitro has been proven previously, the definitive mechanism of PN50G-induced apoptosis in A549 cells in vivo was further investigated. All the results indicated that PN50G significantly suppressed tumor growth in A549 tumor-bearing mice. Tumor cells treated with PN50G were arrested in the G0/G1 phase, and marked changes in the expression of cell cycle-related proteins, including cyclin D1, cyclin A and cyclin B1, were observed. Moreover, western blotting analysis indicated that PN50G triggered the mitochondrial apoptotic pathway, for an increased Bax/Bcl-2 ratio, release of cytochrome c, cleavage of caspase-3 and PRPP in A549 tumor cells were observed. And the decrease in the expression of the translation related protein P70S6K was observed, because PN50G activated AMPK phosphorylation, but inhibited PI3K/AKT phosphorylation and suppressed the activation of the mammalian target of rapamycin (mTOR) induced by PN50G. In vivo imaging was performed on tumor-bearing mice, and the results indicated that PN50G significantly increased the intracellular levels of reactive oxygen species (ROS). Furthermore, it indicated that PN50G promoted the protein expression of Beclin 1 and LC-3 in a dose-dependent manner. All the results suggested that PN50G-mediated apoptosis and autophagy of A549 tumor cells in vivo mainly involved in the mitochondrial pathway and the AMPK/PI3K/mTOR pathway.

Use of biologics and other novel therapies for the treatment of systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a systemic autoimmune disease characterized by vasculopathy, inflammation and fibrosis. These three main disease-determining pathways are the target of the currently available treatments used to possibly modify the progression of disease-related manifestations, although this synergy has not been fully applied on SSc joint, skin or lung involvement yet. Areas covered: we describe the current status of SSc treatment/therapy performing a literature search in MEDLINE/Pubmed and Thomson Reuter's Web of Science for articles published until March 2016. Moreover, ongoing registered clinical trials (RCTs) on SSc were searched through clinicaltrials.gov website. Expert commentary: presently, promising drugs are under evaluation to target the different pathogenic pathways of systemic sclerosis: Tocilizumab and Abatacept for skin and lung fibrosis; Riociguat and Selexipag are approved for pulmonary arterial hypertension but promising anti-fibrotic effects are now being studied. Finally, several anti-fibrotic molecules are currently involved in RCTs, such as Nintedanib, IVA-337, Terguride.

The Expression of the Endogenous mTORC1 Inhibitor Sestrin 2 Is Induced by UVB and Balanced with the Expression Level of Sestrin 1

Sestrin 2 (SESN2) is an evolutionarily conserved regulator of mechanistic target of rapamycin complex 1 (mTORC1) which controls central cellular processes such as protein translation and autophagy. Previous studies have suggested that SESN2 itself is subjected to regulation at multiple levels. Here, we investigated the expression of SESN2 in the skin and in isolated skin cells. SESN2 was detected by immunofluorescence analysis in fibroblasts and keratinocytes of human skin. Differentiation of epidermal keratinocytes was not associated with altered SESN2 expression and siRNA-mediated knockdown of SESN2 did not impair stratum corneum formation in vitro. However, SESN2 was increased in both cell types when the expression of its paralog SESN1 was blocked by siRNA-mediated knock down, indicating a compensatory mechanism for the control of expression. Irradiation with UVB but not with UVA significantly increased SESN2 expression in both keratinocytes and fibroblasts. Upregulation of SESN2 expression could be completely blocked by suppression of p53. These results suggest that SESN2 is dispensable for normal epidermal keratinization but involved in the UVB stress response of skin cells.

Cutaneous Malignancies in Pediatric Solid Organ Transplant Recipients

Pediatric organ transplant recipients (POTRs) are at risk of developing malignancies due to a combination of immunosuppression, impaired DNA damage repair, and infection with oncogenic viruses. The most commonly developed malignancies in this population are skin cancers, which include nonmelanoma skin cancer, melanoma, Kaposi's sarcoma, and anogenital carcinoma. The literature shows that skin cancers account for 13% to 55% of all cancers that occur after transplantation. Given the increasing number and life expectancy of POTRs, prevention and management of skin cancer in these patients is essential, but there is a substantial knowledge gap in our understanding of the differences in skin cancer development, prevention, and management between POTRs and adult organ transplant recipients (AOTRs), for whom more data are available. Substantial differences have been observed in the patterns of malignancy development between POTRs and AOTRs, and data specific to pediatric populations are needed. The objective of this review is to provide updated information on posttransplantation skin cancer development in POTRs, including epidemiologic research on transplant patients and disease development, medication management, surveillance, and education efforts.

mTORC1 and mTORC2 regulate skin morphogenesis and epidermal barrier formation

Mammalian target of rapamycin (mTOR), a regulator of growth in many tissues, mediates its activity through two multiprotein complexes, mTORC1 or mTORC2. The role of mTOR signalling in skin morphogenesis and epidermal development is unknown. Here we identify mTOR as an essential regulator in skin morphogenesis by epidermis-specific deletion of Mtor in mice (mTOR^EKO). mTOR^EKO mutants are viable, but die shortly after birth due to deficits primarily during the early epidermal differentiation programme and lack of a protective barrier development. Epidermis-specific loss of Raptor, which encodes an essential component of mTORC1, confers the same skin phenotype as seen in mTOR^EKO mutants. In contrast, newborns with an epidermal deficiency of Rictor, an essential component of mTORC2, survive despite a hypoplastic epidermis and disruption in late stage terminal differentiation. These findings highlight a fundamental role for mTOR in epidermal morphogenesis that is regulated by distinct functions for mTORC1 and mTORC2.

Molecular Genetics of the PI3K-AKT-mTOR Pathway in Genodermatoses: Diagnostic Implications and Treatment Opportunities

A number of critical signaling pathways are required for homeostatic regulation of cell survival, differentiation, and proliferation during organogenesis. One of them is the PI3K-AKT-mTOR pathway consisting of a cascade of inhibitor/activator molecules. Recently, a number of heritable diseases with skin involvement, manifesting particularly with tissue overgrowth, have been shown to result from mutations in the genes in the PI3K-AKT-mTOR and interacting intracellular pathways. Many of these conditions represent an overlapping spectrum of phenotypic manifestations forming a basis for novel, unifying classifications. Identification of the mutant genes and specific mutations in these patients has implications for diagnostics and genetic counseling and provides a rational basis for the development of novel treatment modalities for this currently intractable group of disorders.

Efficacy and Safety of Sirolimus in the Treatment of Complicated Vascular Anomalies

BACKGROUND AND OBJECTIVES

Complicated vascular anomalies have limited therapeutic options and cause significant morbidity and mortality. This Phase II trial enrolled patients with complicated vascular anomalies to determine the efficacy and safety of treatment with sirolimus for 12 courses; each course was defined as 28 days.

METHODS

Treatment consisted of a continuous dosing schedule of oral sirolimus starting at 0.8 mg/m(2) per dose twice daily, with pharmacokinetic-guided target serum trough levels of 10 to 15 ng/mL. The primary outcomes were responsiveness to sirolimus by the end of course 6 (evaluated according to functional impairment score, quality of life, and radiologic assessment) and the incidence of toxicities and/or infection-related deaths.

RESULTS

Sixty-one patients were enrolled; 57 patients were evaluable for efficacy at the end of course 6, and 53 were evaluable at the end of course 12. No patient had a complete response at the end of course 6 or 12 as anticipated. At the end of course 6, a total of 47 patients had a partial response, 3 patients had stable disease, and 7 patients had progressive disease. Two patients were taken off of study medicine secondary to persistent adverse effects. Grade 3 and higher toxicities attributable to sirolimus included blood/bone marrow toxicity in 27% of patients, gastrointestinal toxicity in 3%, and metabolic/laboratory toxicity in 3%. No toxicity-related deaths occurred.

CONCLUSIONS

Sirolimus was efficacious and well tolerated in these study patients with complicated vascular anomalies. Clinical activity was reported in the majority of the disorders.

Autophagy Modulation by Lanthionine Ketimine Ethyl Ester Improves Long-Term Outcome after Central Fluid Percussion Injury in the Mouse

Diffuse axonal injury is recognized as a progressive and long-term consequence of traumatic brain injury. Axonal injury can have sustained negative consequences on neuronal functions such as anterograde and retrograde transport and cellular processes such as autophagy that depend on cytoarchitecture and axon integrity. These changes can lead to somatic atrophy and an inability to repair and promote plasticity. Obstruction of the autophagic process has been noted after brain injury, and rapamycin, a drug used to stimulate autophagy, has demonstrated positive effects in brain injury models. The optimization of drugs to promote beneficial autophagy without negative side effects could be used to attenuate traumatic brain injury and promote improved outcome. Lanthionine ketimine ethyl ester, a bioavailable derivative of a natural sulfur amino acid metabolite, has demonstrated effects on autophagy both in vitro and in vivo. Thirty minutes after a moderate central fluid percussion injury and throughout the survival period, lanthionine ketimine ethyl ester was administered, and mice were subsequently evaluated for learning and memory impairments and biochemical and histological changes over a 5-week period. Lanthionine ketimine ethyl ester, which we have shown previously to modulate autophagy markers and alleviate pathology and slow cognitive decline in the 3 × TgAD mouse model, spared cognition and pathology after central fluid percussion injury through a mechanism involving autophagy modulation.