Skin Barrier Function: The Interplay of Physical, Chemical, and Immunologic Properties

An intact barrier function of the skin is important in maintaining skin health. The regulation of the skin barrier depends on a multitude of molecular and immunological signaling pathways. By examining the regulation of a healthy skin barrier, including maintenance of the acid mantle and appropriate levels of ceramides, dermatologists can better formulate solutions to address issues that are related to a disrupted skin barrier. Conversely, by understanding specific skin barrier disruptions that are associated with specific conditions, such as atopic dermatitis or psoriasis, the development of new compounds could target signaling pathways to provide more effective relief for patients. We aim to review key factors mediating skin barrier regulation and inflammation, including skin acidity, interleukins, nuclear factor kappa B, and sirtuin 3. Furthermore, we will discuss current and emerging treatment options for skin barrier conditions.

Flavones provide resistance to DUX4-induced toxicity via an mTor-independent mechanism

Facioscapulohumeral muscular dystrophy (FSHD) is among the most common of the muscular dystrophies, affecting nearly 1 in 8000 individuals, and is a cause of profound disability. Genetically, FSHD is linked to the contraction and/or epigenetic de-repression of the D4Z4 repeat array on chromosome 4, thereby allowing expression of the DUX4 gene in skeletal muscle. If the DUX4 transcript incorporates a stabilizing polyadenylation site the myotoxic DUX4 protein will be synthesized, resulting in muscle wasting. The mechanism of toxicity remains unclear, as many DUX4-induced cytopathologies have been described, however cell death does primarily occur through caspase 3/7-dependent apoptosis. To date, most FSHD therapeutic development has focused on molecular methods targeting DUX4 expression or the DUX4 transcript, while therapies targeting processes downstream of DUX4 activity have received less attention. Several studies have demonstrated that inhibition of multiple signal transduction pathways can ameliorate DUX4-induced toxicity, and thus compounds targeting these pathways have the potential to be developed into FSHD therapeutics. To this end, we have screened a group of small molecules curated based on their reported activity in relevant pathways and/or structural relationships with known toxicity-modulating molecules. We have identified a panel of five compounds that function downstream of DUX4 activity to inhibit DUX4-induced toxicity. Unexpectedly, this effect was mediated through an mTor-independent mechanism that preserved expression of ULK1 and correlated with an increase in a marker of active cellular autophagy. This identifies these flavones as compounds of interest for therapeutic development, and potentially identifies the autophagy pathway as a target for therapeutics.

Targeting histone deacetylase-3 blocked epithelial-mesenchymal plasticity and metastatic dissemination in gastric cancer

BACKGROUND AND PURPOSE

Histone deacetylase (HDAC) inhibitors (HDIs) can modulate the epithelial-mesenchymal transition (EMT) progression and inhibit the migration and invasion of cancer cells. Emerging as a novel class of anti-cancer drugs, HDIs are attracted much attention in the field of drug discovery. This study aimed to discern the underlying mechanisms of Honokiol in preventing the metastatic dissemination of gastric cancer cells by inhibiting HDAC3 activity/expression.

EXPERIMENTAL APPROACH

Clinical pathological analysis was performed to determine the relationship between HDAC3 and tumor progression. The effects of Honokiol on pharmacological characterization, functional, transcriptional activities, organelle structure changes, and molecular signaling were analyzed using binding assays, differential scanning calorimetry, luciferase reporter assay, HDAC3 activity, ER stress response element activity, transmission electron microscopy, immune-blotting, and Wnt/β-catenin activity assays. The in vivo effects of Honokiol on peritoneal dissemination were determined by a mouse model and detected by PET/CT tomography.

KEY RESULTS

HDAC3 over-expression was correlated with poor prognosis. Honokiol significantly abolished HDAC3 activity (Y298) via inhibition of NFκBp65/CEBPβ signaling, which could be reversed by the over-expression of plasmids of NFκBp65/CEBPβ. Treatments with 4-phenylbutyric acid (a chemical chaperone) and calpain-2 gene silencing inhibited Honokiol-inhibited NFκBp65/CEBPβ activation. Honokiol increased ER stress markers and inhibited EMT-associated epithelial markers, but decreased Wnt/β-catenin activity. Suppression of HDAC3 by both Honokiol and HDAC3 gene silencing decreased cell migration and invasion in vitro and metastasis in vivo.

CONCLUSIONS AND IMPLICATIONS

Honokiol acts by suppressing HDAC3-mediated EMT and metastatic signaling. By prohibiting HDAC3, metastatic dissemination of gastric cancer may be blocked. Conceptual model showing the working hypothesis on the interaction among Honokiol, HDAC3, and ER stress in the peritoneal dissemination of gastric cancer. Honokiol targeting HDAC3 by ER stress cascade and mitigating the peritoneal spread of gastric cancer. Honokiol-induced ER stress-activated calpain activity targeted HDAC3 and blocked Tyr298 phosphorylation, subsequently blocked cooperating with EMT transcription factors and cancer progression. The present study provides evidence to demonstrate that HDAC3 is a positive regulator of EMT and metastatic growth of gastric cancer cells. The findings here imply that overexpressed HDAC3 is a potential therapeutic target for honokiol to reverse EMT and prevent gastric cancer migration, invasion, and metastatic dissemination. • Honokiol significantly abolished HDAC3 activity on catalytic tyrosine 298 residue site. In addition, Honokiol-induced ER stress markedly inhibited HDAC3 expression via inhibition of NFκBp65/CEBPβ signaling. • HDAC3, which is a positive regulator of metastatic gastric cancer cell growth, can be significantly inhibited by Honokiol. • Opportunities for HDAC3 inhibition may be a potential therapeutic target for preventing gastric cancer metastatic dissemination.

Ant Venom-Based Ceramide Therapy Is Effective Against Atopic Dermatitis In Vivo

BACKGROUND

Atopic dermatitis (AD) is a common skin condition with relatively few therapeutic alternatives. These include corticosteroids, which address inflammation but not superinfection, and Januse kinase (JAK) inhibitors, which have a US Food and Drug Administration (FDA) black box for potential carcinogenicity.

METHODS

We demonstrate that S14, a synthetic derivative of ant venom-derived solenopsin, has potent anti inflammatory effects on the OVA murine model of atopic dermatitis. S14 has demonstrated prior activity in murine psoriasis and has the benefit of ceramide anti-inflammatory effects without being able to be metabolized into proinflammatory sphingosine-1 phosphate.

RESULTS

The efficacy of S14 accompanied by the induction of IL-12 suggests a commonality in inflammatory skin disorders, and our results suggest that pharmacological ceramide restoration will be broadly effective for inflammatory skin disease.

CONCLUSIONS

Solenopsin derivative S14 has anti-inflammatory effects in murine models of AD and psoriasis. This makes S14 a strong candidate for human use, and pre-IND studies are warranted.J Drugs Dermatol. 2023;22(10):1001-1006 doi:10.36849/JDD.7308.

Targeting the Vulnerabilities of Oncogene Activation

Treatment strategies for cancer have progressed greatly in recent decades [...].

Intralesional Chemotherapy for Prostate Cancer: In vivo Proof of Principle

INTRODUCTION

Prostate cancer (PCA) is one of the most common cancers in the world, and current therapies are debilitating to patients. To develop a novel modality for the treatment of PCA, we evaluated the efficacy of intralesional administration of the Sirt3 activator Honokiol (HK) and the NADPH oxidase inhibitor Dibenzolium (DIB).

METHODS

We used a well-established transgenic adenocarcinoma mouse prostate (TRAMP-C2) model of hormone-independent PCA. MTS assay, apoptosis assay, wound healing assay, transwell invasion assay, RT-qPCR, and Western blotting were conducted in vitro, and HK and DIB were intratumorally administered to mice bearing TRAMP-C2 tumors. Tumor size and weight were observed over time. After removing tumors, H-E staining and immunohistochemistry (IHC) staining were conducted.

RESULTS

Treatment by HK or DIB showed an inhibitory effect on cell proliferation and migration in PCA cells. Poor ability to induce apoptosis in vitro, insufficient expression of caspase-3 on IHC staining, and increased necrotic areas on H-E staining indicated that necrosis plays an important role in cell death in treating groups by HK or DIB. RT-PCR, Western blotting, and IHC staining for epithelial mesenchymal transition (EMT) markers suggested that EMT was suppressed by HK and DIB individually. In addition, HK induced activation of CD3. Mouse experiments showed safe antitumor effects in vivo.

CONCLUSIONS

HK and DIB suppressed PCA proliferation and migration. Further research will explore the effects of HK and DIB at the molecular level to reveal new mechanisms that can be exploited as therapeutic modalities.

Honokiol Inhibits SARS-CoV-2 Replication in Cell Culture at a Post-Entry Step

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019, and the resulting pandemic has already caused the death of over 6 million people. There are currently few antivirals approved for treatment of the 2019 coronavirus disease (COVID-19), and more options would be beneficial, not only now but also to increase our preparedness for future coronavirus outbreaks. Honokiol is a small molecule from magnolia trees for which several biological effects have been reported, including anticancer and anti-inflammatory activities. Honokiol has also been shown to inhibit several viruses in cell culture. In this study, we determined that honokiol protected Vero E6 cells from SARS-CoV-2-mediated cytopathic effect, with a 50% effective concentration of 7.8 μM. In viral load reduction assays, honokiol decreased viral RNA copies as well as viral infectious progeny titers. The compound also inhibited SARS-CoV-2 replication in the more relevant human A549 cells expressing angiotensin converting enzyme 2 and transmembrane protease serine 2. Time-of-addition and other assays showed that honokiol inhibited virus replication at a post-entry step of the replication cycle. Honokiol was also effective against more recent variants of SARS-CoV-2, including Omicron, and it inhibited other human coronaviruses as well. Our study suggests that honokiol is an interesting molecule to be evaluated further in animal studies and, when successful, maybe even in clinical trials to investigate its effect on virus replication and pathogenic (inflammatory) host responses. IMPORTANCE Honokiol is a compound that shows both anti-inflammatory and antiviral effects, and therefore its effect on SARS-CoV-2 infection was assessed. This small molecule inhibited SARS-CoV-2 replication in various cell-based infection systems, with up to an ~1,000-fold reduction in virus titer. In contrast to earlier reports, our study clearly showed that honokiol acts on a postentry step of the replication cycle. Honokiol also inhibited different recent SARS-CoV-2 variants and other human coronaviruses (Middle East respiratory syndrome CoV and SARS-CoV), demonstrating its broad spectrum of antiviral activity. The anticoronavirus effect, combined with its anti-inflammatory properties, make honokiol an interesting compound to be further explored in animal coronavirus infection models.

Early Detection and Prognostic Assessment of Cutaneous Melanoma: Consensus on Optimal Practice and the Role of Gene Expression Profile Testing

Importance

Therapy for advanced melanoma has transformed during the past decade, but early detection and prognostic assessment of cutaneous melanoma (CM) remain paramount goals. Best practices for screening and use of pigmented lesion evaluation tools and gene expression profile (GEP) testing in CM remain to be defined.

Objective

To provide consensus recommendations on optimal screening practices and prebiopsy diagnostic, postbiopsy diagnostic, and prognostic assessment of CM.

Evidence Review

Case scenarios were interrogated using a modified Delphi consensus method. Melanoma panelists (n = 60) were invited to vote on hypothetical scenarios via an emailed survey (n = 42), which was followed by a consensus conference (n = 51) that reviewed the literature and the rationale for survey answers. Panelists participated in a follow-up survey for final recommendations on the scenarios (n = 45).

Findings

The panelists reached consensus (≥70% agreement) in supporting a risk-stratified approach to melanoma screening in clinical settings and public screening events, screening personnel recommendations (self/partner, primary care provider, general dermatologist, and pigmented lesion expert), screening intervals, and acceptable appointment wait times. Participants also reached consensus that visual and dermoscopic examination are sufficient for evaluation and follow-up of melanocytic skin lesions deemed innocuous. The panelists reached consensus on interpreting reflectance confocal microscopy and some but not all results from epidermal tape stripping, but they did not reach consensus on use of certain pigmented lesion evaluation tools, such as electrical impedance spectroscopy. Regarding GEP scores, the panelists reached consensus that a low-risk prognostic GEP score should not outweigh concerning histologic features when selecting patients to undergo sentinel lymph node biopsy but did not reach consensus on imaging recommendations in the setting of a high-risk prognostic GEP score and low-risk histology and/or negative nodal status.

Conclusions and Relevance

For this consensus statement, panelists reached consensus on aspects of a risk-stratified approach to melanoma screening and follow-up as well as use of visual examination and dermoscopy. These findings support a practical approach to diagnosing and evaluating CM. Panelists did not reach consensus on a clearly defined role for GEP testing in clinical decision-making, citing the need for additional studies to establish the clinical use of existing GEP assays.

Aggravation of pulmonary fibrosis after knocking down the Aryl hydrocarbon receptor in the Insulin-like growth factor 1 receptor pathway

BACKGROUND AND PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a devastating disease with multiple contributing factors. Insulin-like growth factor 1 receptor (IGF1R), with a reciprocal function to Aryl hydrocarbon receptor (AhR), is known to be involved in the development of airway inflammation. However, the exact relationship between IGF1R and AhR in lung fibrogenesis is unclear. This study aimed to investigate the cascade pathway involving IGF1R and AhR in IPF.

EXPERIMENTAL APPROACH

The AhR and IGF1R expressions were determined in the lungs of IPF patients and in a rodent fibrosis model. Pulmonary fibrosis was evaluated in bleomycin (BLM)-induced lung injury in wild type and AhR knockout (AhR^-/- ) mice. The effects of IGF1R inhibition and AhR activation in vitro on TGF-β1-induced epithelial-mesenchymal transition (EMT) in Beas2B cells and in vivo on BLM-exposed mice were also examined.

KEY RESULTS

There were increased IGF1R levels but diminished AhR expression in the lung tissues of IPF patients and BLM-induced mice. Knockout of AhR aggravated lung fibrosis, while the use of IGF1R inhibitor and AhR agonist significantly attenuated such effects and inhibited TGF-β1-induced EMT in Beas2B cells. Both TGF-β1 and BLM markedly suppressed AhR expression through endoplasmic reticulum (ER) stress and consequently, IGF1R activation. The IGF1R inhibitor and specific knockdown of IGF1R reversed the activation of the TGF-β1 signal pathway.

CONCLUSION AND IMPLICATIONS

In the development of IPF, AhR and IGF1R play opposite roles via the TGF-β/Smad/STAT signaling cascade. The AhR/IGF1R axis is a potential target for the treatment of lung injury and fibrosis.

Introduction of Mutant GNAQ into Endothelial Cells Induces a Vascular Malformation Phenotype with Therapeutic Response to Imatinib

Simple Summary

Mutations in GNAQ underlie vascular malformations, including Sturge-Weber disease. In order to develop novel therapies for lesions with mutant GNAQ, we introduced mutant GNAQ into MS1 endothelial cells. Mutant GNAQ conferred a novel phenotype of progressive vascular malformations in mice. Chromatin analysis revealed upregulation of C-Kit in the vascular endothelial cells, and we found C-Kit to be highly expressed in Sturge-Weber disease. Given that imatinib is an FDA approved multikinase inhibitor that blocks C-Kit, we evaluated it in our mouse model, and showed that imatinib had activity against these vascular malformations. Repurposing imatinib should be evaluated in clinical trials, including Sturge-Weber disease.

Abstract

GNAQ is mutated in vascular and melanocytic lesions, including vascular malformations and nevi. No in vivo model of GNAQ activation in endothelial cells has previously been described. We introduce mutant GNAQ into a murine endothelial cell line, MS1. The resultant transduced cells exhibit a novel phenotype in vivo, with extensive vasoformative endothelial cells forming aberrant lumens similar to those seen in vascular malformations. ATAC-seq analysis reveals activation of c-Kit in the novel vascular malformations. We demonstrate that c-Kit is expressed in authentic human Sturge–Weber vascular malformations, indicating a novel druggable target for Sturge–Weber syndrome. Since c-Kit is targeted by the FDA-approved drug imatinib, we tested the ability of imatinib on the phenotype of the vascular malformations in vivo. Imatinib treated vascular malformations are significantly smaller and have decreased supporting stromal cells surrounding the lumen. Imatinib may be useful in the treatment of human vascular malformations that express c-Kit, including Sturge–Weber syndrome.

Honokiol Acts as a Potent Anti-Fibrotic Agent in the Liver through Inhibition of TGF-β1/SMAD Signaling and Autophagy in Hepatic Stellate Cells

Chronic liver injury may result in hepatic fibrosis, which can progress to cirrhosis and eventually liver failure. There are no drugs that are specifically approved for treating hepatic fibrosis. The natural product honokiol (HNK), a bioactive compound extracted from Magnolia grandiflora, represents a potential tool in the management of hepatic fibrosis. Though HNK has been reported to exhibit suppressive effects in a rat fibrosis model, the mechanisms accounting for this suppression remain unclear. In the present study, the anti-fibrotic effects of HNK on the liver were evaluated in vivo and in vitro. In vivo studies utilized a murine liver fibrosis model, in which fibrosis is induced by treatment with carbon tetrachloride (CCl₄). For in vitro studies, LX-2 human hepatic stellate cells (HSCs) were treated with HNK, and expression of markers of fibrosis, cell viability, the transforming growth factor-β (TGF-β1)/SMAD signaling pathway, and autophagy were analyzed. HNK was well tolerated and significantly attenuated CCl₄-induced liver fibrosis in vivo. Moreover, HNK decreased HSC activation and collagen expression by downregulating the TGF-β1/SMAD signaling pathway and autophagy. These results suggest that HNK is a new potential candidate for the treatment of hepatic fibrosis through suppressing both TGF-β1/SMAD signaling and autophagy in HSCs.

Mitochondrial Metabolism in Melanoma

Melanoma and its associated alterations in cellular pathways have been growing areas of interest in research, especially as specific biological pathways are being elucidated. Some of these alterations include changes in the mitochondrial metabolism in melanoma. Many mitochondrial metabolic changes lead to differences in the survivability of cancer cells and confer resistance to targeted therapies. While extensive work has gone into characterizing mechanisms of resistance, the role of mitochondrial adaptation as a mode of resistance is not completely understood. In this review, we wish to explore mitochondrial metabolism in melanoma and how it impacts modes of resistance. There are several genes that play a major role in melanoma mitochondrial metabolism which require a full understanding to optimally target melanoma. These include BRAF, CRAF, SOX2, MCL1, TRAP1, RHOA, SRF, SIRT3, PTEN, and AKT1. We will be discussing the role of these genes in melanoma in greater detail. An enhanced understanding of mitochondrial metabolism and these modes of resistance may result in novel combinatorial and sequential therapies that may lead to greater therapeutic benefit.

TH2 sensitization in the skin-gut-brain axis: How early-life Th2-mediated inflammation may negatively perpetuate developmental and psychologic abnormalities

We recently reported children with comorbid atopic dermatitis (AD), asthma, allergic rhinitis, and food allergies displaying a 2.7-fold increase in developmental delays.² To this end, we hypothesize unregulated increases in T helper-2 (Th2)-driven inflammation, such as those seen in atopic diseases, can exert deleterious effects on the developing brain. Recognizing that available information is incomplete and that many potential associations are not firmly established, we speculate these effects underlie the association between Th2 sensitization and cognitive dysfunction in children. In this review, we explore the role of Th2 sensitization in the skin-gut-brain axis and explain how it can lead to reduced connectivity and transmission in the developing brain. With a focus on AD, we explore the association between Th2 sensitization and developmental abnormalities such as developmental delays, memory impairment, autism spectrum disorder (ASD), and epilepsy/seizures. As such, we review the available literature to examine the impact of increased IL-4 exposure in early life on the brain. We explore the possible association between Th2 sensitization and psychologic dysfunction such as attention-deficit/hyperactivity disorder (ADHD), depression, anxiety, and suicidal ideation. We also examine the impact that increased exposure to glucocorticoids and neurotrophins in early life exerts on the developing brain. Last, we discuss future directions for the advancement of our knowledge as a scientific community including possible interventions to reduce developmental and psychologic aberrations in children.

Hyperleptinemia in obese state renders luminal breast cancers refractory to tamoxifen by coordinating a crosstalk between Med1, miR205 and ErbB

Obese women with hormone receptor-positive breast cancer exhibit poor response to therapy and inferior outcomes. However, the underlying molecular mechanisms by which obesity/hyperleptinemia may reduce the efficacy of hormonal therapy remain elusive. Obese mice with hyperleptinemia exhibit increased tumor progression and respond poorly to tamoxifen compared to non-obese mice. Exogenous leptin abrogates tamoxifen-mediated growth inhibition and potentiates breast tumor growth even in the presence of tamoxifen. Mechanistically, leptin induces nuclear translocation of phosphorylated-ER and increases the expression of ER-responsive genes, while reducing tamoxifen-mediated gene repression by abrogating tamoxifen-induced recruitment of corepressors NCoR, SMRT, and Mi2 and potentiating coactivator binding. Furthermore, in silico analysis revealed that coactivator Med1 potentially associates with 48 (out of 74) obesity-signature genes. Interestingly, leptin upregulates Med1 expression by decreasing miR-205, and increases its functional activation via phosphorylation, which is mediated by activation of Her2 and EGFR. It is important to note that Med1 silencing abrogates the negative effects of leptin on tamoxifen efficacy. In addition, honokiol or adiponectin treatment effectively inhibits leptin-induced Med1 expression and improves tamoxifen efficacy in hyperleptinemic state. These studies uncover the mechanistic insights how obese/hyperleptinemic state may contribute to poor response to tamoxifen implicating leptin-miR205-Med1 and leptin-Her2-EGFR-Med1 axes, and present bioactive compound honokiol and adipocytokine adiponectin as agents that can block leptin’s negative effect on tamoxifen.

Evaluation of a First-in-Class Proteasome Inhibitor in Patients With Moderate to Severe Rosacea

BACKGROUND

Novel, effective, affordable therapies for rosacea are needed. Innovative methods of assessing response for rosacea treatments are needed as well. This trial was designed to evaluate efficacy and safety of ACU-D1, a novel inhibitor of the 26S protea-some for the treatment of moderate to severe rosacea in a first in human pilot study. In addition, this is the first trial to our knowledge to use Canfield imaging to quantitatively assess responses.

METHODS

This was a 14-week, randomized, double-blinded, placebo-controlled study, performed at two well established rosacea clini-cal trial sites, which randomized 40 adult subjects with moderate to severe rosacea (Investigator’s Global Assessment [IGA]=3/4) to either ACU-D1 (27) or comparator vehicle (13) twice daily. In addition, Canfield imaging was used to assess responses both qualitatively and quantitatively Results: A total of 39 subjects participated, with 38 completing the study. ACU-D1 displayed efficacy in 92% (25 of 27) of patients in reducing inflammatory lesions and a 2 plus grade IGA reduction of clear to near clear in 27% of patients. There was a trend toward improvement in erythema as well in the active arm.

CONCLUSION

This study demonstrates that topical ACU-D1 is safe and well-tolerated by patients in the study and demonstrates efficacy in reducing inflammatory lesions and erythema in patients with rosacea. Improvement was also noted on Canfield imaging, and this modality is likely to be used as an objective measure in the future. Further studies are warranted based on these initial positive results. ClinicalTrials.gov Identifier: NCT03064438 J Drugs Dermatol. 2021;20(6):660-664. doi:10.36849/JDD.5925.

Honokiol Prevents Non-Alcoholic Steatohepatitis-Induced Liver Cancer via EGFR Degradation through the Glucocorticoid Receptor-MIG6 Axis

Non-alcoholic steatohepatitis (NASH) has become a serious public health problem associated with metabolic syndrome. The mechanisms by which NASH induces hepatocellular carcinoma (HCC) remain unknown. There are no approved drugs for treating NASH or preventing NASH-induced HCC. We used a genetic mouse model in which HCC was induced via high-fat diet feeding. This mouse model strongly resembles human NASH-induced HCC. The natural product honokiol (HNK) was tested for its preventative effects against NASH progression to HCC. Then, to clarify the mechanisms underlying HCC development, human HCC cells were treated with HNK. Human clinical specimens were also analyzed to explore this study's clinical relevance. We found that epidermal growth factor receptor (EGFR) signaling was hyperactivated in the livers of mice with NASH and human HCC specimens. Inhibition of EGFR signaling by HNK drastically attenuated HCC development in the mouse model. Mechanistically, HNK accelerated the nuclear translocation of glucocorticoid receptor (GR) and promoted mitogen-inducible gene 6 (MIG6)/ERBB receptor feedback inhibitor 1 (ERRFI1) expression, leading to EGFR degradation and thereby resulting in robust tumor suppression. In human samples, EGFR-positive HCC tissues and their corresponding non-tumor tissues exhibited decreased ERRFI1 mRNA expression. Additionally, GR-positive non-tumor liver tissues displayed lower EGFR expression. Livers from patients with advanced NASH exhibited decreased ERRFI1 expression. EGFR degradation or inactivation represents a novel approach for NASH-HCC treatment and prevention, and the GR-MIG6 axis is a newly defined target that can be activated by HNK and related compounds.

Honokiol Bis-Dichloroacetate Is a Selective Allosteric Inhibitor of the Mitochondrial Chaperone TRAP1

Aims: TNF receptor-associated protein 1 (TRAP1), the mitochondrial paralog of the heat shock protein 90 (Hsp90) family of molecular chaperones, is required for neoplastic growth in several tumor cell models, where it inhibits succinate dehydrogenase (SDH) activity, thus favoring bioenergetic rewiring, maintenance of redox homeostasis, and orchestration of a hypoxia-inducible factor 1-alpha (HIF1α)-mediated pseudohypoxic program. Development of selective TRAP1 inhibitors is instrumental for targeted development of antineoplastic drugs, but it has been hampered up to now by the high degree of homology among catalytic pockets of Hsp90 family members. The vegetal derivative honokiol and its lipophilic bis-dichloroacetate ester, honokiol DCA (HDCA), are small-molecule compounds with antineoplastic activity. HDCA leads to oxidative stress and apoptosis in in vivo tumor models and displays an action that is functionally opposed to that of TRAP1, as it induces both SDH and the mitochondrial deacetylase sirtuin-3 (SIRT3), which further enhances SDH activity. We investigated whether HDCA could interact with TRAP1, inhibiting its chaperone function, and the effects of HDCA on tumor cells harboring TRAP1. Results: An allosteric binding site in TRAP1 is able to host HDCA, which inhibits TRAP1 but not Hsp90 ATPase activity. In neoplastic cells, HDCA reverts TRAP1-dependent downregulation of SDH, decreases proliferation rate, increases mitochondrial superoxide levels, and abolishes tumorigenic growth. Innovation: HDCA is a potential lead compound for the generation of antineoplastic approaches based on the allosteric inhibition of TRAP1 chaperone activity. Conclusions: We have identified a selective TRAP1 inhibitor that can be used to better dissect TRAP1 biochemical functions and to tailor novel tumor-targeting strategies.

Inhibitors of cytoskeletal dynamics in malignant mesothelioma

Malignant mesotheliomas (MMs) are highly aggressive mesenchymal tumors that originate from mesothelial cells lining serosal cavities; i.e., the pleura, peritoneum, and pericardium. Classically, there is a well-established link between asbestos exposure, oxidative stress, release of reactive oxygen species, and chronic inflammatory mediators that leads to progression of MMs. MMs have an intermediate phenotype, with co-expression of mesenchymal and epithelial markers and dysregulated communication between the mesothelium and the microenvironment. We have previously shown that the organization and function of key cytoskeletal components can distinguish highly invasive cell lines from those more indolent. Here, we used these tools to study three different types of small-molecule inhibitors, where their common feature is their influence on production of reactive oxygen species. One of these, imipramine blue, was particularly effective in counteracting some key malignant properties of highly invasive MM cells. This opens a new possibility for targeted inhibition of MMs based on well-established molecular mechanisms.

Tris DBA ameliorates IgA nephropathy by blunting the activating signal of NLRP3 inflammasome through SIRT1- and SIRT3-mediated autophagy induction

Tris (dibenzylideneacetone) dipalladium (Tris DBA), a small‐molecule palladium complex, can inhibit cell growth and proliferation in pancreatic cancer, lymphocytic leukaemia and multiple myeloma. Given that this compound is particularly active against B‐cell malignancies, we have been suggested that it can alleviate immune complexes (ICs)–mediated conditions, especially IgA nephropathy (IgAN). The therapeutic effects of Tris DBA on glomerular cell proliferation and renal inflammation and mechanism of action were examined in a mouse model of IgAN. Treatment of IgAN mice with Tris DBA resulted in markedly improved renal function, albuminuria and renal pathology, including glomerular cell proliferation, neutrophil infiltration, sclerosis and periglomerular inflammation in the renal interstitium, together with (Clin J Am Soc Nephrol. 2011, 6, 1301‐1307) reduced mitochondrial ROS generation; (Am J Physiol‐Renal Physiol. 2011. 301, F1218‐F1230) differentially regulated autophagy and NLRP3 inflammasome; (Clin J Am Soc Nephrol. 2012, 7, 427‐436) inhibited phosphorylation of JNK, ERK and p38 MAPK signalling pathways, and priming signal of the NLRP3 inflammasome; and (Free Radic Biol Med. 2013, 61, 285‐297) blunted NLRP3 inflammasome activation through SIRT1‐ and SIRT3‐mediated autophagy induction, in renal tissues or cultured macrophages. In conclusion, Tris DBA effectively ameliorated the mouse IgAN model and targeted signalling pathways downstream of ICs‐mediated interaction, which is a novel immunomodulatory strategy. Further development of Tris DBA as a therapeutic candidate for IgAN is warranted.

Induction of STK11-dependent cytoprotective autophagy in breast cancer cells upon honokiol treatment

Cancer cells hijack autophagy pathway to evade anti-cancer therapeutics. Many molecular signaling pathways associated with drug-resistance converge on autophagy induction. Honokiol (HNK), a natural phenolic compound purified from Magnolia grandiflora, has recently been shown to impede breast tumorigenesis and, in the present study, we investigated whether breast cancer cells evoke autophagy to modulate therapeutic efficacy and functional networks of HNK. Indeed, breast cancer cells exhibit increased autophagosomes-accumulation, MAP1LC3B-II/LC3B-II-conversion, expression of ATG proteins as well as elevated fusion of autophagosomes and lysosomes upon HNK treatment. Breast cancer cells treated with HNK demonstrate significant growth inhibition and apoptotic induction, and these biological processes are blunted by macroautophagy/autophagy. Consequently, inhibiting autophagosome formation, abrogating autophagosome-lysosome fusion or genetic-knockout of BECN1 and ATG7 effectively increase HNK-mediated apoptotic induction and growth inhibition. Next, we explored the functional impact of tumor suppressor STK11 in autophagy induction in HNK-treated cells. STK11-silencing abrogates LC3B-II-conversion, and blocks autophagosome/lysosome fusion and lysosomal activity as illustrated by LC3B-Rab7 co-staining and DQ-BSA assay. Our results exemplify the cytoprotective nature of autophagy invoked in HNK-treated breast cancer cells and put forth the notion that a combined strategy of autophagy inhibition with HNK would be more effective. Indeed, HNK and chloroquine (CQ) show synergistic inhibition of breast cancer cells and HNK-CQ combination treatment effectively inhibits breast tumorigenesis and metastatic progression. Tumor-dissociated cells from HNK-CQ treated tumors exhibit abrogated invasion and migration potential. Together, these results implicate that breast cancer cells undergo cytoprotective autophagy to circumvent HNK and a combined treatment with HNK and CQ can be a promising therapeutic strategy for breast cancer.

Tris DBA Ameliorates Accelerated and Severe Lupus Nephritis in Mice by Activating Regulatory T Cells and Autophagy and Inhibiting the NLRP3 Inflammasome

Tris (dibenzylideneacetone) dipalladium (Tris DBA), a small-molecule palladium complex, has been shown to inhibit cell growth and proliferation in pancreatic cancer, lymphocytic leukemia, and multiple myeloma. In the current study, we examined the therapeutic effects of Tris DBA on glomerular cell proliferation, renal inflammation, and immune cells. Treatment of accelerated and severe lupus nephritis (ASLN) mice with Tris DBA resulted in improved renal function, albuminuria, and pathology, including measurements of glomerular cell proliferation, cellular crescents, neutrophils, fibrinoid necrosis, and tubulointerstitial inflammation in the kidneys as well as scoring for glomerulonephritis activity. The treated ASLN mice also showed significantly decreased glomerular IgG, IgM, and C3 deposits. Furthermore, the compound was able to 1) inhibit bone marrow-derived dendritic cell-mediated T cell functions and reduce serum anti-dsDNA autoantibody levels; 2) differentially regulate autophagy and both the priming and activation signals of the NLRP3 inflammasome; and 3) suppress the phosphorylation of JNK, ERK, and p38 MAPK signaling pathways. Tris DBA improved ASLN in mice through immunoregulation by blunting the MAPK (ERK, JNK)-mediated priming signal of the NLRP3 inflammasome and by regulating the autophagy/NLRP3 inflammasome axis. These results suggest that the pure compound may be a drug candidate for treating the accelerated and deteriorated type of lupus nephritis.

Propranolol exhibits activity against hemangiomas independent of beta blockade

Propranolol is a widely used beta blocker that consists of a racemic mixture of R and S stereoisomers. Only the S stereoisomer has significant activity against the beta-adrenergic receptor. A fortuitous clinical observation was made in an infant who received propranolol for cardiac disease, and regression of a hemangioma of infancy was noted. This has led to the widespread use of propranolol for the treatment of large and life-threatening hemangiomas of infancy. Infants receiving propranolol require monitoring to ensure that they do not suffer from side effects related to beta blockade. The exact mechanism of activity of propranolol in hemangioma of infancy is unknown. In this study, we treated hemangioma stem cells with both beta blockade active S- and inactive R-propranolol and looked for genes that were coordinately regulated by this treatment. Among the genes commonly downregulated, Angiopoietin-like 4 (ANGPTL4) was among the most regulated. We confirmed that propranolol isomers downregulated ANGPTL4 in endothelial cells, with greater downregulation of ANGPTL4 using the beta blockade inactive R-propranolol. ANGPTL4 is present in human hemangiomas of infancy. Finally, R-propranolol inhibited the growth of bEnd.3 hemangioma cells in vivo. The implication of this is that hemangioma growth can be blocked without the side effects of beta blockade. Given that humans have been exposed to racemic propranolol for decades and thus to R-propranolol, clinical development of R-propranolol for hemangiomas of infancy and other angiogenic diseases is warranted.

Tris DBA palladium is an orally available inhibitor of GNAQ mutant uveal melanoma in vivo

Uveal melanoma is a rare but often lethal malignancy and is the leading cause of death due to an ophthalmic condition. Uveal melanoma is often diagnosed at a late stage and has a strong propensity to hepatic metastasis. Recently, the most common driver mutations in uveal melanoma have been identified, predominantly in the G-proteins GNAQ. This pattern differs from that of cutaneous melanoma in which Braf and Nras predominate. There are no current clinically used agents that target GNAQ mutations, unlike the use of Braf inhibitors in cutaneous melanoma. We tested the novel agent Tris DBA palladium and found that it was markedly more effective against GNAQ mutant melanomas than wild type uveal melanomas. Given that ARF6 has recently been discovered as a node in GNAQ mutations, we evaluated the efficacy of Tris DBA palladium on ARF6 signaling and found that it was effective in inhibiting ARF6 activation. Finally, Tris DBA palladium was orally effective against GNAQ mutant melanoma in vivo. Tris DBA Palladium deserves further evaluation as a systemic agent for uveal melanoma.

Topical Application of Cinnamaldehyde Promotes Faster Healing of Skin Wounds Infected with Pseudomonas aeruginosa

Wound healing can be delayed following colonization and infection with the common bacterium Pseudomonas aeruginosa. While multiple therapies are used for their treatment, these are ineffective, expensive, and labour-intensive. Thus, there is an enormous unmet need for the treatment of infected wounds. Cinnamaldehyde, the major component of cinnamon oil, is well known for its antimicrobial properties. Herein, we investigated the effects of sub-inhibitory concentrations of cinnamaldehyde in the virulence of P. aeruginosa. We also assessed its healing potential in P. aeruginosa-infected mouse skin wounds and the mechanisms involved in this response. Sub-inhibitory concentrations of cinnamaldehyde reduced P. aeruginosa metabolic rate and its ability to form biofilm and to cause haemolysis. Daily topical application of cinnamaldehyde on P. aeruginosa-infected skin wounds reduced tissue bacterial load and promoted faster healing. Lower interleukin-17 (IL-17), vascular endothelial growth factor (VEGF) and nitric oxide levels were detected in cinnamaldehyde-treated wound samples. Blockage of transient receptor potential ankyrin 1, the pharmacological target of cinnamaldehyde, abrogated its healing activity and partially reversed the inhibitory actions of this compound on VEGF and IL-17 generation. We suggest that topical application of sub-inhibitory concentrations of cinnamaldehyde may represent an interesting approach to improve the healing of P. aeruginosa-infected skin wounds.

Myofibroblast proliferation and heterogeneity are supported by macrophages during skin repair

During tissue repair, myofibroblasts produce extracellular matrix (ECM) molecules for tissue resilience and strength. Altered ECM deposition can lead to tissue dysfunction and disease. Identification of distinct myofibroblast subsets is necessary to develop treatments for these disorders. We analyzed profibrotic cells during mouse skin wound healing, fibrosis, and aging and identified distinct subpopulations of myofibroblasts, including adipocyte precursors (APs). Multiple mouse models and transplantation assays demonstrate that proliferation of APs but not other myofibroblasts is activated by CD301b-expressing macrophages through insulin-like growth factor 1 and platelet-derived growth factor C. With age, wound bed APs and differential gene expression between myofibroblast subsets are reduced. Our findings identify multiple fibrotic cell populations and suggest that the environment dictates functional myofibroblast heterogeneity, which is driven by fibroblast-immune interactions after wounding.

Chemoprevention agents for melanoma: A path forward into phase 3 clinical trials

Recent progress in the treatment of advanced melanoma has led to unprecedented improvements in overall survival and, as these new melanoma treatments have been developed and deployed in the clinic, much has been learned about the natural history of the disease. Now is the time to apply that knowledge toward the design and clinical evaluation of new chemoprevention agents. Melanoma chemoprevention has the potential to reduce dramatically both the morbidity and the high costs associated with treating patients who have metastatic disease. In this work, scientific and clinical melanoma experts from the national Melanoma Prevention Working Group, composed of National Cancer Trials Network investigators, discuss research aimed at discovering and developing (or repurposing) drugs and natural products for the prevention of melanoma and propose an updated pipeline for translating the most promising agents into the clinic. The mechanism of action, preclinical data, epidemiological evidence, and results from available clinical trials are discussed for each class of compounds. Selected keratinocyte carcinoma chemoprevention studies also are considered, and a rationale for their inclusion is presented. These data are summarized in a table that lists the type and level of evidence available for each class of agents. Also included in the discussion is an assessment of additional research necessary and the likelihood that a given compound may be a suitable candidate for a phase 3 clinical trial within the next 5 years.

ROS modifiers and NOX4 affect the expression of the survivin-associated radio-adaptive response

The survivin-associated radio-adaptive response can be induced following exposure to ionizing radiation in the dose range from 5 to 100 mGy, and its magnitude of expression is dependent upon the TP53 mutational status of cells and ROS signaling. The purpose of the study was to investigate the potential role of ROS in the development of the survivin-associated adaptive response. Utilizing human colon carcinoma HCT116 TP53 wild type (WT) and HCT116 isogenic TP53 null mutant (Mut) cell cultures, the roles of inter- and intracellular ROS signaling on expression of the adaptive response as evidenced by changes in intracellular translocation of survivin measured by ELISA, and cell survival determined by a standard colony forming assay were investigated using ROS modifying agents that include emodin, N-acetyl-L-cysteine (NAC), fulvene-5, honokiol, metformin and rotenone. The role of NADPH oxidase 4 (NOX4) in the survivin-associated adaptive response was investigated by transfecting HCT116 cells, both WT and Mut, with two different NOX4 siRNA oligomers and Western blotting. A dose of 5 mGy or a 15 min exposure to 50 µM of the ROS producing drug emodin were equally effective in inducing a pro-survival adaptive response in TP53 WT and a radio-sensitization adaptive response in TP53 Mut HCT116 cells. Each response was associated with a corresponding translocation of survivin into the cytoplasm or nucleus, respectively. Exposure to 10 mM NAC completely inhibited both responses. Exposure to 10 µM honokiol induced responses similar to those observed following NAC exposure in TP53 WT and Mut cells. The mitochondrial complex 1 inhibitor rotenone was effective in reducing both cytoplasmic and nuclear survivin levels, but was ineffective in altering the expression of the adaptive response in either TP53 WT or Mut cells. In contrast, both metformin and fulvene-5, inhibitors of NOX4, facilitated the reversal of TP53 WT and Mut adaptive responses from pro-survival to radio-sensitization and vice versa, respectively. These changes were accompanied by corresponding reversals in the translocation of survivin to the nuclei of TP53 WT and to the cytoplasm of TP53 Mut cells. The potential role of NOX4 in the expression of the survivin-associated adaptive response was investigated by transfecting HCT116 cells with NOX4 siRNA oligomers to inhibit NOX4 expression. Under these conditions NOX4 expression was inhibited by about 50%, resulting in a reversal in the expression of the TP53 WT and Mut survivin-associated adaptive responses as was observed following metformin and fulvene-5 treatment. Exposure to 5 mGy resulted in enhanced NOX4 expression by about 40% in both TP53 WT and Mut cells, in contrast to only a 1-2% increase following a 2 Gy only exposure. Utilizing mixed cultures of HCT116 TP53 WT and isogenic null Mut cells, as few as 10% TP53 Mut cells were sufficient to control the expression of the remaining 90% WT cells and resulted in an overall radio-sensitization response accompanied by the nuclear translocation of survivin characteristic of homogeneous TP53 Mut populations.

Targeting the Plasticity of Psoriasis

Psoriasis is a common inflammatory condition found in 1-2% of the population. The greatest advances in psoriasis treatment have occurred in patients with severe psoriasis, moving from systemic small molecules including methotrexate, cyclosporine, and retinoids to targeted agents against psoriasis-associated cytokines, such as TNF-α, IL-12, IL-23, and IL-17. Although the new biologics do not have the same adverse effects as the systemic drugs, they do predispose to systemic infections (and perhaps cancer), and they are extremely expensive. The focus on biologic therapies has been accompanied by a relative neglect of small molecules, which can be used either topically or systemically. No small molecule has been able to compete significantly with topical glucocorticoids, the mainstay of treatment for mild to moderate psoriasis for more than half a century.

SIRT3 is attenuated in systemic sclerosis skin and lungs, and its pharmacologic activation mitigates organ fibrosis

Constitutive fibroblast activation is responsible for organ fibrosis in fibrotic disorders including systemic sclerosis (SSc), but the underlying mechanisms are not fully understood, and effective therapies are lacking. We investigated the expression of the mitochondrial deacetylase sirtuin 3 (SIRT3) and its modulation by hexafluoro, a novel fluorinated synthetic honokiol analogue, in the context of fibrosis. We find that augmenting cellular SIRT3 by forced expression in normal lung and skin fibroblasts, or by hexafluoro treatment, blocked intracellular TGF-ß signaling and fibrotic responses, and mitigated the activated phenotype of SSc fibroblasts. Moreover, hexafluoro attenuated mitochondrial and cytosolic reactive oxygen species (ROS) accumulation in TGF-β-treated fibroblasts. Remarkably, we found that the expression of SIRT3 was significantly reduced in SSc skin biopsies and explanted fibroblasts, and was suppressed by TGF-β treatment in normal fibroblasts. Moreover, tissue levels of acetylated MnSOD, a sensitive marker of reduced SIRT3 activity, were dramatically enhanced in lesional skin and lung biopsies from SSc patients. Mice treated with hexafluoro showed substantial attenuation of bleomycin-induced fibrosis in the lung and skin. Our findings reveal a cell-autonomous function for SIRT3 in modulating fibrotic responses, and demonstrate the ability of a novel pharmacological SIRT3 agonist to attenuate fibrosis in vitro and in vivo. In light of the impaired expression and activity of SIRT3 associated with organ fibrosis in SSc, pharmacological approaches for augmenting SIRT3 might have therapeutic potential.

Abstract P6-06-04: Targeting replication stress in triple negative breast cancer treatment regimen: An emerging approach

Triple-negative breast cancers (TNBCs) represent aggressive heterogeneous subtype of breast cancer with poor clinical outcome. TNBCs have been reported to have high levels of replication stress due to i) various oncogene activations (C-myc or EGFR) ii) germline BRCA mutations iii) “BRCAness” in the absence of BRCA mutations in sporadic TNBCs. Replication stress is known to cause genomic instability, promote tumorigenesis and plays a critical role in therapy resistance in TNBCs. Therefore, targeting replication stress has emerged as an effective approach for better TNBC treatment through further downregulation of the remaining checkpoints to induce catastrophic failure of TNBC cells proliferation. Herein, we evaluated the anticancer efficacy of Carbazole Blue (CB), a synthetic analogue of Carbazole, on TNBC cells growth and progression. Our results demonstrated that CB inhibits short and long term viability of TNBC (MDA-MB-231, MDA-MB-468 and BT549) cells in a dose dependent manner without affecting normal mammary epithelial (MCF-10A) cells. In addition, CB treatment significantly reduced proliferation of TNBC cells, as evidenced by the BrdU proliferation assay. Consistent with this, our results further demonstrated that CB treatment induced G1/S cell cycle arrest and apoptosis in TNBCs. Importantly, systemic delivery of CB using nanoparticle-based delivery approach suppressed breast cancer growth without inducing toxicity, in preclinical orthotopic xenograft and PDX mouse models of TNBC. Furthermore, our gene microarray analysis revealed that CB treatment modulates the expression and activity of several genes known to be involved in DNA replication (CDC6, CDT1, MCMs, Claspin, POLE and PCNA) and associated DNA repair machinery such as (XRCC3, Exo1 and RAD51), which play pivotal roles in replication stress. Our results for the first time highlight the potential use of CB as a novel and potent therapeutic agent for treating TNBCs. As exploiting replication stress to treat cancer is gaining major interest, compound/s that may induce replication stress and inhibit DNA repair ability of cancer cells, has immense translational potential.

Citation Format: Rajamanickam S, Park JH, Bates K, Timilsina S, Eedunuri VK, Onyeagucha B, Subbarayalu P, Abdelfattah N, Jung KH, Favours E, Mohammad TA, Chen H-IH, Vadlamudi RK, Chen Y, Kaipparettu BA, Arbiser JL, Rao MK. Targeting replication stress in triple negative breast cancer treatment regimen: An emerging approach [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-06-04.

Cooperation of imipramine blue and tyrosine kinase blockade demonstrates activity against chronic myeloid leukemia

The use of tyrosine kinase inhibitors (TKI), including nilotinib, has revolutionized the treatment of chronic myeloid leukemia (CML). However current unmet clinical needs include combating activation of additional survival signaling pathways in persistent leukemia stem cells after long-term TKI therapy. A ubiquitous signaling alteration in cancer, including CML, is activation of reactive oxygen species (ROS) signaling, which may potentiate stem cell activity and mediate resistance to both conventional chemotherapy and targeted inhibitors. We have developed a novel nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, imipramine blue (IB) that targets ROS generation. ROS levels are known to be elevated in CML with respect to normal hematopoietic stem/progenitor cells and not corrected by TKI. We demonstrate that IB has additive benefit with nilotinib in inhibiting proliferation, viability, and clonogenic function of TKI-insensitive quiescent CD34⁺ CML chronic phase (CP) cells while normal CD34⁺ cells retained their clonogenic capacity in response to this combination therapy in vitro. Mechanistically, the pro-apoptotic activity of IB likely resides in part through its dual ability to block NF-κB and re-activate the tumor suppressor protein phosphatase 2A (PP2A). Combining BCR-ABL1 kinase inhibition with NADPH oxidase blockade may be beneficial in eradication of CML and worthy of further investigation.

Honokiol is a FOXM1 antagonist

Honokiol is a natural product and an emerging drug for a wide variety of malignancies, including hematopoietic malignancies, sarcomas, and common epithelial tumors. The broad range of activity of honokiol against numerous malignancies with diverse genetic backgrounds suggests that honokiol is inhibiting an activity that is common to multiple malignancies. Oncogenic transcription factor FOXM1 is one of the most overexpressed oncoproteins in human cancer. Here we found that honokiol inhibits FOXM1-mediated transcription and FOXM1 protein expression. More importantly, we found that honokiol’s inhibitory effect on FOXM1 is a result of binding of honokiol to FOXM1. This binding is specific to honokiol, a dimerized allylphenol, and was not observed in compounds that either were monomeric allylphenols or un-substituted dihydroxy phenols. This indicates that both substitution and dimerization of allylphenols are required for physical interaction with FOXM1. We thus demonstrate a novel and specific mechanism for FOXM1 inhibition by honokiol, which partially may explain its anticancer activity in cancer cells.

Honokiol Radiosensitizes Squamous Cell Carcinoma of the Head and Neck by Downregulation of Survivin

Purpose: Previous studies revealed diverging results regarding the role of survivin in squamous cell carcinoma of the head and neck (SCCHN). This study aimed to evaluate the clinical significance of survivin expression in SCCHN; the function of survivin in DNA-damage repair following ionizing radiation therapy (RT) in SCCHN cells; and the potential of honokiol to enhance RT through downregulation of survivin.Experimental Design: Expression of survivin in SCCHN patient primary tumor tissues (n = 100) was analyzed and correlated with clinical parameters. SCCHN cell lines were used to evaluate the function of survivin and the effects of honokiol on survivin expression in vitro and in vivoResults: Overexpression of survivin was significantly associated with lymph nodes' metastatic status (P = 0.025), worse overall survival (OS), and disease-free survival (DFS) in patients receiving RT (n = 65, OS: P = 0.024, DFS: P = 0.006) and in all patients with SCCHN (n = 100, OS: P = 0.002, DFS: P = 0.003). In SCCHN cells, depletion of survivin led to increased DNA damage and cell death following RT, whereas overexpression of survivin increased clonogenic survival. RT induced nuclear accumulation of survivin and its molecular interaction with γ-H2AX and DNA-PKCs. Survivin specifically bound to DNA DSB sites induced by I-SceI endonuclease. Honokiol (which downregulates survivin expression) in combination with RT significantly augmented cytotoxicity in SCCHN cells with acquired radioresistance and inhibited growth in SCCHN xenograft tumors.Conclusions: Survivin is a negative prognostic factor and is involved in DNA-damage repair induced by RT. Targeting survivin using honokiol in combination with RT may provide novel therapeutic opportunities. Clin Cancer Res; 24(4); 858-69. ©2017 AACR.

Honokiol bis-dichloroacetate (Honokiol DCA) demonstrates activity in vemurafenib-resistant melanoma in vivo

The majority of human melanomas bears BRAF mutations and thus is treated with inhibitors of BRAF, such as vemurafenib. While patients with BRAF mutations often demonstrate an initial dramatic response to vemurafenib, relapse is extremely common. Thus, novel agents are needed for the treatment of these aggressive melanomas. Honokiol is a small molecule compound derived from Magnolia grandiflora that has activity against solid tumors and hematopoietic neoplasms. In order to increase the lipophilicity of honokiol, we have synthesized honokiol DCA, the dichloroacetate ester of honokiol. In addition, we synthesized a novel fluorinated honokiol analog, bis-trifluoromethyl-bis-(4-hydroxy-3-allylphenyl) methane (hexafluoro). Both compounds exhibited activity against A375 melanoma in vivo, but honokiol DCA was more active. Gene arrays comparing treated with vehicle control tumors demonstrated induction of the respiratory enzyme succinate dehydrogenase B (SDHB) by treatment, suggesting that our honokiol analogs induce respiration in vivo. We then examined its effect against a pair of melanomas, LM36 and LM36R, in which LM36R differs from LM36 in that LM36R has acquired vemurafenib resistance. Honokiol DCA demonstrated in vivo activity against LM36R (vemurafenib resistant) but not against parental LM36. Honokiol DCA and hexafluoro inhibited the phosphorylation of DRP1, thus stimulating a phenotype suggestive of respiration through mitochondrial normalization. Honokiol DCA may act in vemurafenib resistant melanomas to increase both respiration and reactive oxygen generation, leading to activity against aggressive melanoma in vivo.

Regression of diffuse B-cell lymphoma of the leg with intralesional gentian violet

In this case report, a patient of primary cutaneous diffuse B-cell lymphoma, leg type was treated with intralesional gentian violet as she was judged to be too medically fragile for conventional chemotherapy due to advanced age and multiple serious comorbidities. Gentian violet (crystal violet/hexamethyl pararosaniline) is a triphenylmethane dye. It has been shown to have an inhibitory effect on NADPH oxidase, an enzyme family which is found in abundance in reactive oxygen-driven tumors such as melanoma and lymphoma. We hypothesize that intralesional gentian violet treatment caused signalling changes in the lymphoma which allowed for immune clearance of the lymphoma. Complete resolution of the patient's lesion was noted on a follow-up visit.

Treatment of Hailey-Hailey Disease With Low-Dose Naltrexone

Importance

Hailey-Hailey disease is a severe genetic blistering disease of intertriginous skin locations that can lead to poor quality of life and increased morbidities. Multiple therapies are available with inconsistent outcomes and potentially severe adverse effects.

Objective

To determine whether low-dose naltrexone is an effective treatment for Hailey-Hailey disease.

Design, Setting, and Participants

This study was a case series performed at a dermatology outpatient clinic of 3 patients with severe Hailey-Hailey disease recalcitrant to at least 4 therapies.

Interventions

Low-dose naltrexone, 3 mg nightly, titrated to 4.5 mg nightly in 2 patients.

Main Outcomes and Measures

Reduction in size of lesions as well as subjective improvement of symptoms.

Results

All 3 patients noted significant healing of erosions and plaques starting from the peripheral aspect within 1 to 2 weeks of treatment, and clinical resolution of lesions within 2 months. Discontinuation of low-dose naltrexone resulted in flaring of symptoms, which cleared within 2 to 3 days on rechallenge with low-dose naltrexone.

Conclusions and Relevance

We present herein 3 cases of patients with severe Hailey-Hailey disease treated with low-dose naltrexone who achieved clinical resolution of symptoms. The success of these cases suggests low-dose naltrexone as a novel therapy for Hailey-Hailey disease. The possible mechanism may involve low-dose naltrexone influencing opioid or toll-like receptor signaling to improve calcium mobilization and improve keratinocyte differentiation and wound healing. Future studies are needed to clarify the mechanism and to define the role of low-dose naltrexone for treatment of Hailey-Hailey disease.

Overcoming Resistance to Cetuximab with Honokiol, A Small-Molecule Polyphenol

Overexpression and activation of the EGFR have been linked to poor prognosis in several human cancers. Cetuximab is a mAb against EGFR that is used for the treatment in head and neck squamous cell carcinoma (HNSCC) and metastatic colorectal cancer. Unfortunately, most tumors have intrinsic or will acquire resistance to cetuximab during the course of therapy. Honokiol is a natural compound found in the bark and leaves of the Chinese Magnolia tree and is established to have several anticancer properties without appreciable toxicity. In this study, we hypothesized that combining cetuximab and honokiol treatments could overcome acquired resistance to cetuximab. We previously developed a model of acquired resistance to cetuximab in non-small cell lung cancer H226 cell line. Treatment of cetuximab-resistant clones with honokiol and cetuximab resulted in a robust antiproliferative response. Immunoblot analysis revealed the HER family and their signaling pathways were downregulated after combination treatment, most notably the proliferation (MAPK) and survival (AKT) pathways. In addition, we found a decrease in phosphorylation of DRP1 and reactive oxygen species after combination treatment in cetuximab-resistant clones, which may signify a change in mitochondrial function. Furthermore, we utilized cetuximab-resistant HNSCC patient-derived xenografts (PDX) to test the benefit of combinatorial treatment in vivo There was significant growth delay in PDX tumors after combination treatment with a subsequent downregulation of active MAPK, AKT, and DRP1 signaling as seen in vitro Collectively, these data suggest that honokiol is a promising natural compound in overcoming acquired resistance to cetuximab. Mol Cancer Ther; 17(1); 204-14. ©2017 AACR.

Peroxisome proliferator-activated receptor gamma (PPARγ) is central to the initiation and propagation of human angiomyolipoma, suggesting its potential as a therapeutic target

Angiomyolipoma (AML), the most common benign renal tumor, can result in severe morbidity from hemorrhage and renal failure. While mTORC1 activation is involved in its growth, mTORC1 inhibitors fail to eradicate AML, highlighting the need for new therapies. Moreover, the identity of the AML cell of origin is obscure. AML research, however, is hampered by the lack of in vivo models. Here, we establish a human AML‐xenograft (Xn) model in mice, recapitulating AML at the histological and molecular levels. Microarray analysis demonstrated tumor growth in vivo to involve robust PPARG‐pathway activation. Similarly, immunostaining revealed strong PPARG expression in human AML specimens. Accordingly, we demonstrate that while PPARG agonism accelerates AML growth, PPARG antagonism is inhibitory, strongly suppressing AML proliferation and tumor‐initiating capacity, via a TGFB‐mediated inhibition of PDGFB and CTGF. Finally, we show striking similarity between AML cell lines and mesenchymal stem cells (MSCs) in terms of antigen and gene expression and differentiation potential. Altogether, we establish the first in vivo human AML model, which provides evidence that AML may originate in a PPARG‐activated renal MSC lineage that is skewed toward adipocytes and smooth muscle and away from osteoblasts, and uncover PPARG as a regulator of AML growth, which could serve as an attractive therapeutic target.