UV irradiation induces Snail expression by AP-1 dependent mechanism in human skin keratinocytes

Identification of New Markers of Angiogenic Sprouting Using Transcriptomics: New Role for RND3

BACKGROUND

New blood vessel formation requires endothelial cells to transition from a quiescent to an invasive phenotype. Transcriptional changes are vital for this switch, but a comprehensive genome-wide approach focused exclusively on endothelial cell sprout initiation has not been reported.

METHODS

Using a model of human endothelial cell sprout initiation, we developed a protocol to physically separate cells that initiate the process of new blood vessel formation (invading cells) from noninvading cells. We used this model to perform multiple transcriptomics analyses from independent donors to monitor endothelial gene expression changes.

RESULTS

Single-cell population analyses, single-cell cluster analyses, and bulk RNA sequencing revealed common transcriptomic changes associated with invading cells. We also found that collagenase digestion used to isolate single cells upregulated the Fos proto-oncogene transcription factor. Exclusion of Fos proto-oncogene expressing cells revealed a gene signature consistent with activation of signal transduction, morphogenesis, and immune responses. Many of the genes were previously shown to regulate angiogenesis and included multiple tip cell markers. Upregulation of SNAI1 (snail family transcriptional repressor 1), PTGS2 (prostaglandin synthase 2), and JUNB (JunB proto-oncogene) protein expression was confirmed in invading cells, and silencing JunB and SNAI1 significantly reduced invasion responses. Separate studies investigated rounding 3, also known as RhoE, which has not yet been implicated in angiogenesis. Silencing rounding 3 reduced endothelial invasion distance as well as filopodia length, fitting with a pathfinding role for rounding 3 via regulation of filopodial extensions. Analysis of in vivo retinal angiogenesis in Rnd3 heterozygous mice confirmed a decrease in filopodial length compared with wild-type littermates.

CONCLUSIONS

Validation of multiple genes, including rounding 3, revealed a functional role for this gene signature early in the angiogenic process. This study expands the list of genes associated with the acquisition of a tip cell phenotype during endothelial cell sprout initiation.

MAPKs in the early steps of senescence implemEMTation

Evidence is accumulating that the earliest stages of the DNA damage response can direct cells toward senescence instead of other cell fates. In particular, tightly regulated signaling through Mitogen-Activated Protein Kinases (MAPKs) in early senescence can lead to a sustained pro-survival program and suppress a pro-apoptotic program. Importantly, an epithelial-to-mesenchymal Transition (EMT)-like program appears essential for preventing apoptosis and favoring senescence following DNA damage. In this review, we discuss how MAPKs might influence EMT features to promote a senescent phenotype that increases cell survival at the detriment of tissue function.

Cancer stem cells (CSCs): key player of radiotherapy resistance and its clinical significance

Cancer stem cells (CSCs) are self-renewing and slow-multiplying micro subpopulations in tumour microenvironments. CSCs contribute to cancer's resistance to radiation (including radiation) and other treatments. CSCs control the heterogeneity of the tumour. It alters the tumour's microenvironment cellular singling and promotes epithelial-to-mesenchymal transition (EMT). Current research decodes the role of extracellular vesicles (EVs) and CSCs interlink in radiation resistance. Exosome is a subpopulation of EVs and originated from plasma membrane. It is secreted by several active cells. It involed in cellular communication and messenger of healthly and multiple pathological complications. Exosomal biological active cargos (DNA, RNA, protein, lipid and glycan), are capable to transform recipient cells' nature. The molecular signatures of CSCs and CSC-derived exosomes are potential source of cancer theranostics development. This review discusse cancer stem cells, radiation-mediated CSCs development, EMT associated with CSCs, the role of exosomes in radioresistance development, the current state of radiation therapy and the use of CSCs and CSCs-derived exosomes biomolecules as a clinical screening biomarker for cancer. This review gives new researchers a reason to keep an eye on the next phase of scientific research into cancer theranostics that will help mankind.

Dendrobium nobile Lindl. Polysaccharides protect fibroblasts against UVA-induced photoaging via JNK/c-Jun/MMPs pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl. is an orchid species that is found throughout Asia, including Thailand, Laos, Vietnam, and China. It has been used to treat tumors, hyperglycemia, hyperlipidemia, and neurological disorders caused by aging in recent decades.

AIM OF THE STUDY

To investigate the antagonistic effect of Dendrobium nobile Lindl. Polysaccharides (DNLP) on UVA-induced photoaging of Human foreskin fibroblasts (HFF-1) and explore its possible anti-aging mechanisms.

MATERIALS AND METHODS

An in vitro photoaging model of dermal fibroblasts was established with multiple UVA irradiations. Fibroblasts were treated with 0.06 mg/ml, 0.18 mg/ml, 0.54 mg/ml of DNLP one day before photodamage induction. The levels of reactive oxygen species (ROS), Malondialdehyde (MDA), cell viability and longevity, Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione peroxidase (GSH-Px) enzymatic activities were determined. We examined how DNLP ameliorates the effects of photoaging, the JNK/c-Fos/c-Jun pathway, senescence-associated β-galactosidase (SA-β-Gal), and MMP expression levels were measured.

RESULTS

UVA irradiation reduced the viability, lifespan, and proliferation of HFF-1 cells, increased ROS and lipid peroxidation and decreased the activities of free radical scavenging enzyme systems SOD, CAT, and GSH-Px. DNLP treatment can reverse UVA damage, reduce SA-β-Gal expression, reduce phosphorylation activation of the JNK/c-Fos/c-Jun pathway and inhibit MMP-1, MMP-2 MMP-3, and MMP-9 protein expression.

CONCLUSIONS

DNLP can effectively inhibit UVA damage to HFF-1 and prevent cell senescence. Its mechanism of action may increase antioxidant enzyme activity while inhibiting JNK pathway activation and MMPs expression.

A tEMTing target? Clinical and experimental evidence for epithelial-mesenchymal transition in the progression of cutaneous squamous cell carcinoma (a scoping systematic review)

Cutaneous squamous cell carcinoma (cSCC) is a disease with globally rising incidence and poor prognosis for patients with advanced or metastatic disease. Epithelial-mesenchymal transition (EMT) is a driver of metastasis in many carcinomas, and cSCC is no exception. We aimed to provide a systematic overview of the clinical and experimental evidence for EMT in cSCC, with critical appraisal of type and quality of the methodology used. We then used this information as rationale for potential drug targets against advanced and metastatic cSCC. All primary literature encompassing clinical and cell-based or xenograft experimental studies reporting on the role of EMT markers or related signalling pathways in the progression of cSCC were considered. A screen of 3443 search results yielded 86 eligible studies comprising 44 experimental studies, 22 clinical studies, and 20 studies integrating both. From the clinical studies a timeline illustrating the alteration of EMT markers and related signalling was evident based on clinical progression of the disease. The experimental studies reveal connections of EMT with a multitude of factors such as genetic disorders, cancer-associated fibroblasts, and matrix remodelling via matrix metalloproteinases and urokinase plasminogen activator. Additionally, EMT was found to be closely tied to environmental factors as well as to stemness in cSCC via NFκB and β-catenin. We conclude that the canonical EGFR, canonical TGF-βR, PI3K/AKT and NFκB signalling are the four signalling pillars that induce EMT in cSCC and could be valuable therapeutic targets. Despite the complexity, EMT markers and pathways are desirable biomarkers and drug targets for the treatment of advanced or metastatic cSCC.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

hTERT-Driven Immortalization of RDEB Fibroblast and Keratinocyte Cell Lines Followed by Cre-Mediated Transgene Elimination

The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased β-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures.

Long noncoding RNA MAPKAPK5-AS1 promotes colorectal cancer progression by cis-regulating the nearby gene MK5 and acting as a let-7f-1-3p sponge

BACKGROUND

Long noncoding RNAs (lncRNAs) are considered critical regulators in cancers; however, the clinical significance and mechanisms of MAPKAPK5-AS1 (hereinafter referred to as MK5-AS1) in colorectal cancer (CRC) remain mostly unknown.

METHODS

In this study, quantitative real-time PCR (qPCR) and western blotting were utilized to detect the levels of MK5-AS1, let-7f-1-3p and MK5 (MAPK activated protein kinase 5) in CRC tissues and cell lines. The biological functions of MK5-AS1, let-7f-1-3p and MK5 in CRC cells were explored using Cell Counting Kit-8 (CCK8), colony formation and transwell assays. The potential mechanisms of MK5-AS1 were evaluated by RNA pull-down, RNA immunoprecipitation (RIP), dual luciferase reporter assay, chromatin immunoprecipitation (ChIP) and bioinformatics analysis. The effects of MK5-AS1 and MK5 on CRC were investigated by a xenotransplantation model.

RESULTS

We confirmed that MK5-AS1 was significantly increased in CRC tissues. Knockdown of MK5-AS1 suppressed cell migration and invasion in vitro and inhibited lung metastasis in mice. Mechanistically, MK5-AS1 regulated SNAI1 expression by sponging let-7f-1-3p and cis-regulated the adjacent gene MK5. Moreover, MK5-AS1 recruited RBM4 and eIF4A1 to promote the translation of MK5. Our study verified that MK5 promoted the phosphorylation of c-Jun, which activated the transcription of SNAI1 by directly binding to its promoter.

CONCLUSIONS

MK5-AS1 cis-regulated the nearby gene MK5 and acted as a let-7f-1-3p sponge, playing a vital role in CRC tumorigenesis. This study could provide novel insights into molecular therapeutic targets of CRC.

β-Mangostin inhibits the metastatic power of cervical cancer cells attributing to suppression of JNK2/AP-1/Snail cascade

β-Mangostin is a natural mangostin with potent anticancer activity against various cancers. In this study, we further explored the anticancer activity of β-mangostin on cervical cancer cells. β-Mangostin did not affect cell viability and cell cycle distribution in HeLa and SiHa cells; however, it dose-dependently inhibited the migration and invasion of both the human cervical cancer cell lines. In addition, we observed that β-mangostin suppressed the expression of integrin αV and β3 and the downstream focal adhesion kinase/Src signaling. We also found that Snail was involved in the β-mangostin inhibited cell migration and invasion of HeLa cell. Then, our findings showed that β-mangostin reduced both nuclear translocation and messenger RNA expression of AP-1 and demonstrated that AP-1 could target to the Snail promoter and induce Snail expression. Kinase cascade analysis and reporter assay showed that JNK2 was involved in the inhibition of AP-1/Snail axis by β-mangostin in HeLa cells. These results indicate that β-mangostin can inhibit the mobility and invasiveness of cervical cancer cells, which may attribute to the suppression of both integrin/Src signaling and JNK2-mediated AP-1/Snail axis. This suggests that β-mangostin has potential antimetastatic potential against cervical cancer cells.

Toward Modeling Context-Specific EMT Regulatory Networks Using Temporal Single Cell RNA-Seq Data

Epithelial-mesenchymal transition (EMT) is well established as playing a crucial role in cancer progression and being a potential therapeutic target. To elucidate the gene regulation that drives the decision making of EMT, many previous studies have been conducted to model EMT gene regulatory circuits (GRCs) using interactions from the literature. While this approach can depict the generic regulatory interactions, it falls short of capturing context-specific features. Here, we explore the effectiveness of a combined bioinformatics and mathematical modeling approach to construct context-specific EMT GRCs directly from transcriptomics data. Using time-series single cell RNA-sequencing data from four different cancer cell lines treated with three EMT-inducing signals, we identify context-specific activity dynamics of common EMT transcription factors. In particular, we observe distinct paths during the forward and backward transitions, as is evident from the dynamics of major regulators such as NF-KB (e.g., NFKB2 and RELB) and AP-1 (e.g., FOSL1 and JUNB). For each experimental condition, we systematically sample a large set of network models and identify the optimal GRC capturing context-specific EMT states using a mathematical modeling method named Random Circuit Perturbation (RACIPE). The results demonstrate that the approach can build high quality GRCs in certain cases, but not others and, meanwhile, elucidate the role of common bioinformatics parameters and properties of network structures in determining the quality of GRCs. We expect the integration of top-down bioinformatics and bottom-up systems biology modeling to be a powerful and generally applicable approach to elucidate gene regulatory mechanisms of cellular state transitions.

Snail1: A Transcriptional Factor Controlled at Multiple Levels

Snail1 transcriptional factor plays a key role in the control of epithelial to mesenchymal transition and fibroblast activation. As a consequence, Snail1 expression and function is regulated at multiple levels from gene transcription to protein modifications, affecting its interaction with specific cofactors. In this review, we describe the different elements that control Snail1 expression and its activity both as transcriptional repressor or activator.

Synergistic effect of phototherapy and chemotherapy on bladder cancer cells

Drug resistance as an important barrier to cancer treatment, has a close relation with alteration of cancer metabolism. Therefore, in this study the synergistic effect of phototherapy and chemotherapy were investigated on the bladder cancer cells viability. The cytotoxicity effect of blue light irradiation was measured by the MTT assay. Glucose consumption, lactate and ammonium formation were analyzed in the blue LED-irradiated cancer cells culture. Also, the expression of some genes involved in apoptosis and epithelial-mesenchymal transition was assessed using real-time PCR in comparison with the control group. The analysis of the results indicated that blue light irradiation inhibited the cell viability in a dose-dependent manner. Blue light irradiation decreased the cell viability by 7% and 19% (p < .05) in 5637 cells at doses of 8.7 J/cm² and 17.5 J/cm² in comparison with the control group respectively. Glucose consumption, lactate and ammonium formation diminished in the blue LED-irradiated 5637 cells in both doses. The real time PCR results indicated that the expression of Bax increased in blue light-irradiated cells. In addition, the cell cycle analysis showed that blue light irradiation arrested the bladder cancer in the G1 phase. Also, the effect of combination therapy on cancer cells was investigated in presence of blue light irradiation and cisplatin. The obtained results of the MTT assay indicated that blue light irradiation enhance the cytotoxicity effect of cisplatin on bladder cancer cells.

The deubiquitinating enzyme USP48 stabilizes TRAF2 and reduces E-cadherin-mediated adherens junctions

The tumor necrosis factor receptor-associated factor 2 (TRAF2) is a second messenger adaptor protein that plays an essential role in propagating TNF-α-mediated signaling pathways. Modulation of TRAF2 activity by ubiquitination is well studied; however, the deubiquitinating enzyme (DUB), which regulates TRAF2 stability, has not been identified. Here we reveal USP48 as the first identified DUB to deubiquitinate and stabilize TRAF2 in epithelial cells. Down-regulation of USP48 increases K48-linked polyubiquitination of TRAF2 and reduces TRAF2 protein levels. Interestingly, USP48 only targets the TRAF2 related to JNK pathway, not the TRAF2 related to NF-κB and p38 pathways. USP48 is serine phosphorylated in response to TNF-α. The phosphorylation is catalyzed by glycogen synthase kinase 3β (GSK3β), ultimately resulting in increases in USP48 DUB activity. Furthermore, we reveal a new biologic function of TRAF2 that contributes to epithelial barrier dysfunction, which is attenuated by knockdown of USP48. Inhibition of TRAF2/JNK pathway increases E (epithelial)-cadherin expression and enhances epithelial barrier integrity, while knockdown of USP48 attenuates TNF-α/JNK pathway and increases E-cadherin expression and cell-cell junction in epithelial cells. These data, taken together, indicate that USP48 stabilizes TRAF2, which is promoted by GSK3β-mediated phosphorylation. Further, down-regulation of USP48 increases E-cadherin expression and epithelial barrier integrity through reducing TRAF2 stability.-Li, S., Wang, D., Zhao, J., Weathington, N. M., Shang, D., Zhao, Y. The deubiquitinating enzyme USP48 stabilizes TRAF2 and reduces E-cadherin-mediated adherens junctions.

Scaffolding proteins in the development and maintenance of the epidermal permeability barrier

The skin of mammals and other terrestrial vertebrates protects the organism against the external environment, preventing heat, water and electrolyte loss, as well as entry of chemicals and pathogens. Impairments in the epidermal permeability barrier function are associated with the genesis and/or progression of a variety of pathological conditions, including genetic inflammatory diseases, microbial and viral infections, and photodamage induced by UV radiation. In mammals, the outside-in epidermal permeability barrier is provided by the joint action of the outermost cornified layer, together with assembled tight junctions in granular keratinocytes found in the layers underneath. Tight junctions serve as both outside-in and inside-out barriers, and impede paracellular movements of ions, water, macromolecules and microorganisms. At the molecular level, tight junctions consist of integral membrane proteins that form an extracellular seal between adjacent cells, and associate with cytoplasmic scaffold proteins that serve as links with the actin cytoskeleton. In this review, we address the roles that scaffold proteins play specifically in the establishment and maintenance of the epidermal permeability barrier, and how various pathologies alter or impair their functions.

N-Acetylglutaminoyl-S-farnesyl-L-cysteine (SIG-1191): an anti-inflammatory molecule that increases the expression of the aquaglyceroporin, aquaporin-3, in human keratinocytes

Isoprenylcysteine (IPC) small molecules were discovered as signal transduction modulating compounds ~25 years ago. More recently, IPC molecules have demonstrated antioxidant and anti-inflammatory properties in a variety of dermal cells as well as antimicrobial activity, representing a novel class of compounds to ameliorate skin conditions and disease. Here, we demonstrate a new IPC compound, N-acetylglutaminoyl-S-farnesyl-L-cysteine (SIG-1191), which inhibits UVB-induced inflammation blocking pro-inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) production. To investigate further the previously reported hydrating potential of IPC compounds, SIG-1191 was tested for its ability to modulate aquaporin expression. Specifically, aquaporin 3 (AQP3) the most abundant aquaporin found in skin has been reported to play a key role in skin hydration, elasticity and barrier repair. Results show here for the first time that SIG-1191 increases AQP3 expression in both cultured normal human epidermal keratinocytes as well as when applied topically in a three-dimensional (3D) reconstructed human skin equivalent. Additionally, SIG-1191 dose dependently increased AQP3 protein levels, as determined by specific antibody staining, in the epidermis of the 3D skin equivalents. To begin to elucidate which signaling pathways SIG-1191 may be modulating to increase AQP3 levels, we used several pharmacological pathway inhibitors and determined that AQP3 expression is mediated by the Mitogen-activated protein kinase/Extracellular signal-regulated kinase kinase (MEK) pathway. Altogether, these data suggest SIG-1191 represents a new IPC derivative with anti-inflammatory activity that may also promote increased skin hydration based on its ability to increase AQP3 levels.

Induction of metastasis, cancer stem cell phenotype, and oncogenic metabolism in cancer cells by ionizing radiation

Radiation therapy is one of the major tools of cancer treatment, and is widely used for a variety of malignant tumours. Radiotherapy causes DNA damage directly by ionization or indirectly via the generation of reactive oxygen species (ROS), thereby destroying cancer cells. However, ionizing radiation (IR) paradoxically promotes metastasis and invasion of cancer cells by inducing the epithelial-mesenchymal transition (EMT). Metastasis is a major obstacle to successful cancer therapy, and is closely linked to the rates of morbidity and mortality of many cancers. ROS have been shown to play important roles in mediating the biological effects of IR. ROS have been implicated in IR-induced EMT, via activation of several EMT transcription factors—including Snail, HIF-1, ZEB1, and STAT3—that are activated by signalling pathways, including those of TGF-β, Wnt, Hedgehog, Notch, G-CSF, EGFR/PI3K/Akt, and MAPK. Cancer cells that undergo EMT have been shown to acquire stemness and undergo metabolic changes, although these points are debated. IR is known to induce cancer stem cell (CSC) properties, including dedifferentiation and self-renewal, and to promote oncogenic metabolism by activating these EMT-inducing pathways. Much accumulated evidence has shown that metabolic alterations in cancer cells are closely associated with the EMT and CSC phenotypes; specifically, the IR-induced oncogenic metabolism seems to be required for acquisition of the EMT and CSC phenotypes. IR can also elicit various changes in the tumour microenvironment (TME) that may affect invasion and metastasis. EMT, CSC, and oncogenic metabolism are involved in radioresistance; targeting them may improve the efficacy of radiotherapy, preventing tumour recurrence and metastasis. This study focuses on the molecular mechanisms of IR-induced EMT, CSCs, oncogenic metabolism, and alterations in the TME. We discuss how IR-induced EMT/CSC/oncogenic metabolism may promote resistance to radiotherapy; we also review efforts to develop therapeutic approaches to eliminate these IR-induced adverse effects.

ASPP2 suppresses stem cell-like characteristics and chemoresistance by inhibiting the Src/FAK/Snail axis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of death in cancer patients worldwide. Understanding the molecular pathogenesis of HCC recurrence and chemoresistance is key to improving patients' prognosis. In this study, we report that downregulation of ASPP2, a member of the ankyrin-repeat-containing, SH3-domain-containing, and proline-rich-region-containing protein (ASPP) family, bestowed HCC cells with stem-like properties and resistance to chemotherapy, including the expansion of side population fractions, formation of hepatospheroids, expression of stem cell-associated genes, loss of chemosensitivity, and increased tumorigenicity in immunodeficient mice. An expression profiling assay revealed that ASPP2 specifically repressed focal adhesion kinase (FAK)/Src/extracellular signal regulated kinase (ERK) signaling. ASPP2 does this by physically interacting with C-terminal Src kinase (CSK) and stimulating its kinase activity, which eventually leads to activator protein 1 (AP1)-mediated downregulation of Snail expression. In addition, pharmacologic inhibition of Src attenuated the effects of ASPP2 deficiency. Our findings present functional and mechanistic insight into the critical role of ASPP2 in the inhibition of HCC stemness and drug resistance and may provide a new strategy for therapeutic combinations to treat HCC.

Osteopontin-A Master Regulator of Epithelial-Mesenchymal Transition

Osteopontin (OPN) plays an important functional role in both physiologic and pathologic states. OPN is implicated in the progression of fibrosis, cancer, and metastatic disease in several organ systems. The epithelial-mesenchymal transition (EMT), first described in embryology, is increasingly being recognized as a significant contributor to fibrotic phenotypes and tumor progression. Several well-established transcription factors regulate EMT and are conserved across tissue types and organ systems, including TWIST, zinc finger E-box-binding homeobox (ZEB), and SNAIL-family members. Recent literature points to an important relationship between OPN and EMT, implicating OPN as a key regulatory component of EMT programs. In this review, OPN’s interplay with traditional EMT activators, both directly and indirectly, will be discussed. Also, OPN’s ability to restructure the tissue and tumor microenvironment to indirectly modify EMT will be reviewed. Together, these diverse pathways demonstrate that OPN is able to modulate EMT and provide new targets for directing therapeutics.

TGFβ-induced invasion of prostate cancer cells is promoted by c-Jun-dependent transcriptional activation of Snail1

High levels of transforming growth factor-β (TGFβ) correlate with poor prognosis for patients with prostate cancer and other cancers. TGFβ is a multifunctional cytokine and crucial regulator of cell fate, such as epithelial to mesenchymal transition (EMT), which is implicated in cancer invasion and progression. TGFβ conveys its signals upon binding to type I and type II serine/threonine kinase receptors (TβRI/II); phosphorylation of Smad2 and Smad3 promotes their association with Smad4, which regulates expression of targets genes, such as Smad7, p21, and c-Jun. TGFβ also activates the ubiquitin ligase tumor necrosis factor receptor-associated factor 6 (TRAF6), which associates with TβRI and activates the p38 mitogen-activated protein kinase (MAPK) pathway. Snail1 is a key transcription factor, induced by TGFβ that promotes migration and invasion of cancer cells. In this study, we have identified a novel binding site for c-Jun in the promoter of the Snail1 gene and report that the activation of the TGFβ–TRAF6–p38 MAPK pathway promotes both c-Jun expression and its activation via p38α-dependent phosphorylation of c-Jun at Ser63. The TRAF6-dependent activation of p38 also leads to increased stability of c-Jun, due to p38-dependent inactivation of glycogen synthase kinase (GSK) 3β by phosphorylation at Ser9. Thus, our findings elucidate a novel role for the p38 MAPK pathway in stimulated cells, leading to activation of c-Jun and its binding to the promoter of Snail1, thereby triggering motility and invasiveness of aggressive human prostate cancer cells.

Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K

Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression.

Targeting Fyn in Ras-transformed cells induces F-actin to promote adherens junction-mediated cell-cell adhesion

Fyn, a member of the Src family kinases (SFK), is an oncogene in murine epidermis and is associated with cell-cell adhesion turnover and induction of cell migration. Additionally, Fyn upregulation has been reported in multiple tumor types, including cutaneous squamous cell carcinoma (cSCC). Introduction of active H-Ras(G12V) into the HaCaT human keratinocyte cell line resulted in upregulation of Fyn mRNA (200-fold) and protein, while expression of other SFKs remained unaltered. Transduction of active Ras or Fyn was sufficient to induce an epithelial-to-mesenchymal transition in HaCaT cells. Inhibition of Fyn activity, using siRNA or the clinical SFK inhibitor Dasatinib, increased cell-cell adhesion and rapidly (5-60 min) increased levels of cortical F-actin. Fyn inhibition with siRNA or Dasatinib also induced F-actin in MDA-MB-231 breast cancer cells, which have elevated Fyn. F-actin co-localized with adherens junction proteins, and Dasatinib-induced cell-cell adhesion could be blocked by Cytochalasin D, indicating that F-actin polymerization was a key initiator of cell-cell adhesion through the adherens junction. Conversely, inhibiting cell-cell adhesion with low Ca(2+) media did not block Dasatinib-induced F-actin polymerization. Inhibition of the Rho effector kinase ROCK blocked Dasatinib-induced F-actin and cell-cell adhesion, implicating relief of Rho GTPase inhibition as a mechanism of Dasatinib-induced cell-cell adhesion. Finally, topical Dasatinib treatment significantly reduced total tumor burden in the SKH1 mouse model of UV-induced skin carcinogenesis. Together these results identify the promotion of actin-based cell-cell adhesion as a newly described mechanism of action for Dasatinib and suggest that Fyn inhibition may be an effective therapeutic approach in treating cSCC.

CopA3 peptide prevents ultraviolet-induced inhibition of type-I procollagen and induction of matrix metalloproteinase-1 in human skin fibroblasts

Ultraviolet (UV) exposure is well-known to induce premature aging, which is mediated by matrix metalloproteinase-1 (MMP-1) activity. A 9-mer peptide, CopA3 (CopA3) was synthesized from a natural peptide, coprisin, which is isolated from the dung beetle Copris tripartitus. As part of our continuing search for novel bioactive natural products, CopA3 was investigated for its in vitro anti-skin photoaging activity. UV-induced inhibition of type-I procollagen and induction of MMP-1 were partially prevented in human skin fibroblasts by CopA3 peptide in a dose-dependent manner. At a concentration of 25 μM, CopA3 nearly completely inhibited MMP-1 expression. These results suggest that CopA3, an insect peptide, is a potential candidate for the prevention and treatment of skin aging.

Age-dependent alterations of decorin glycosaminoglycans in human skin

Proteoglycans, a family of glycosaminoglycan (GAG) conjugated proteins, are important constituents of human skin connective tissue (dermis) and are essential for maintaining mechanical strength of the skin. Age-related alterations of dermal proteoglycans have not been fully elucidated. We quantified transcripts of 20 known interstitial proteoglycans in human skin and found that decorin was the most highly expressed. Decorin was predominantly produced by dermal fibroblasts. Decorin was localized in dermal extracellular matrix with GAG bound to type I collagen fibrils. Analysis of decorin extracted from young (21–30 years) and aged (>80 years) sun-protected human buttock skin revealed that decorin molecular size in aged skin is significantly smaller than in young skin. The average size of decorin protein did not alter, indicating size of GAG chain is reduced in aged, compared to young skin. This age-dependent alteration of decorin GAG may contribute to skin fragility of elderly people.

Synergistic effect of lung tumor-associated dendritic cell-derived HB-EGF and CXCL5 on cancer progression

The interaction between cancer cells and their microenvironment is a paradoxical cycle that exacerbates cancer progression and results in metastasis. Our study investigated the mechanism underlying the synergistic enhancement of release of soluble factors from tumor-associated dendritic cells and its effect on cancer development. The combination of HB-EGF (heparin-binding EGF-like growth factor) and CXCL5 (CXCL5/epithelial neutrophil-activating peptide-78) produced a strong synergistic effect on cancer proliferation, epithelial-mesenchymal transition, migration and invasion. CXCL5 not only potentiated the classical EGFR pathway and the AKT and ERK/RSK1/2 signaling pathways but also increased the phosphorylation of heat shock protein 27 (HSP27), which was slightly increased in A549 cells treated with either HB-EGF or CXCL5 only. Phosphorylated HSP27 stabilized sustained AKT activity by direct interaction, leading to enhanced tumor spheroid formation. Knockdown of HSP27 by shRNA decreased HB-EGF plus CXCL5-mediated tumor spheroid formation in a three-dimensional culture system, suggesting that AKT/HSP27 was required for HB-EGF/CXCL5-mediated cancer progression. Inhibiting RSK also reduces the modulation of c-Fos phosphorylation, Snail upregulation and cell migration by HB-EGF plus CXCL5, suggesting a synergistic effect of ERK/RSK and HB-EGF plus CXCL5 on cell migration. In mice, CXCL5 antibody synergistically enhances the efficiency of the tyrosine kinase inhibitor, gefitinib, without increasing its toxicity. These results provide evidence that elucidates potential cross-points between extracellular signals affecting lung cancer progression. Targeting CXCL5 may provide therapeutic benefits for lung cancer chemotherapy or immunotherapy.

Solar ultraviolet irradiation induces decorin degradation in human skin likely via neutrophil elastase

Exposure of human skin to solar ultraviolet (UV) irradiation induces matrix metalloproteinase-1 (MMP-1) activity, which degrades type I collagen fibrils. Type I collagen is the most abundant protein in skin and constitutes the majority of skin connective tissue (dermis). Degradation of collagen fibrils impairs the structure and function of skin that characterize skin aging. Decorin is the predominant proteoglycan in human dermis. In model systems, decorin binds to and protects type I collagen fibrils from proteolytic degradation by enzymes such as MMP-1. Little is known regarding alterations of decorin in response to UV irradiation. We found that solar-simulated UV irradiation of human skin in vivo stimulated substantial decorin degradation, with kinetics similar to infiltration of polymorphonuclear (PMN) cells. Proteases that were released from isolated PMN cells degraded decorin in vitro. A highly selective inhibitor of neutrophil elastase blocked decorin breakdown by proteases released from PMN cells. Furthermore, purified neutrophil elastase cleaved decorin in vitro and generated fragments with similar molecular weights as those resulting from protease activity released from PMN cells, and as observed in UV-irradiated human skin. Cleavage of decorin by neutrophil elastase significantly augmented fragmentation of type I collagen fibrils by MMP-1. Taken together, these data indicate that PMN cell proteases, especially neutrophil elastase, degrade decorin, and this degradation renders collagen fibrils more susceptible to MMP-1 cleavage. These data identify decorin degradation and neutrophil elastase as potential therapeutic targets for mitigating sun exposure-induced collagen fibril degradation in human skin.

Regulation of protein translation and c-Jun expression by prostate tumor overexpressed 1

Prostate tumor overexpressed-1 (PTOV1), a modulator of the Mediator transcriptional regulatory complex, is expressed at high levels in prostate cancer and other neoplasias in association with a more aggressive disease. Here we show that PTOV1 interacts directly with receptor of activated protein C kinase 1 (RACK1), a regulator of protein kinase C and Jun signaling and also a component of the 40S ribosome. Consistent with this interaction, PTOV1 was associated with ribosomes and its overexpression promoted global protein synthesis in prostate cancer cells and COS-7 fibroblasts in a mTORC1-dependent manner. Transfection of ectopic PTOV1 enhanced the expression of c-Jun protein without affecting the levels of c-Jun or RACK1 mRNA. Conversely, knockdown of PTOV1 caused significant declines in global protein synthesis and c-Jun protein levels. High levels of PTOV1 stimulated the motility and invasiveness of prostate cancer cells, which required c-Jun, whereas knockdown of PTOV1 strongly inhibited the tumorigenic and metastatic potentials of PC-3 prostate cancer cells. In human prostate cancer samples, the expression of high levels of PTOV1 in primary and metastatic tumors was significantly associated with increased nuclear localization of active c-Jun. These results unveil new functions of PTOV1 in the regulation of protein translation and in the progression of prostate cancer to an invasive and metastatic disease.

Epigenetic control of epithelial-mesenchymal-transition in human cancer

Development and tissue homeostasis as well as carcinogenesis share the evolutionary conserved process of epithelial-mesenchymal transition (EMT). EMT enables differentiated epithelial cells to trans-differentiate to a mesenchymal phenotype which is associated with diverse cellular properties including altered morphology, migration and invasion and stemness. In physiological development and tissue homeostasis, EMT exerts beneficial functions for structured tissue formation and maintenance. Under pathological conditions, EMT causes uncontrolled tissue repair and organ fibrosis, as well as the induction of tumor growth, angiogenesis and metastasis in the context of cancer progression. Particularly, the metastatic process is essentially linked to diverse EMT-driven functions which give the mesenchymal differentiated tumor cells the capacity to migrate and form micrometastases in distant organs. Recent analyses of the mechanisms controlling EMT revealed a significant epigenetic regulatory impact reflecting the reversible nature of EMTs. As several approaches of epigenetic therapy are already under clinical evaluation, including inhibitors of DNA methyl transferase and histone deacetylase, targeting the epigenetic regulation of EMT may represent a promising therapeutic option in the future. Therefore, we undertook this review to reassess the current knowledge on the roles of epigenetic control in the regulation of EMT in human cancer. These recent findings are discussed in view of their implications on future diagnostic and therapeutic strategies.

Xenobiotic metabolism capacities of human skin in comparison with a 3D epidermis model and keratinocyte-based cell culture as in vitro alternatives for chemical testing: activating enzymes (Phase I)

Skin is important for the absorption and metabolism of exposed chemicals such as cosmetics or pharmaceuticals. The Seventh Amendment to the EU Cosmetics Directive prohibits the use of animals for cosmetic testing for certain endpoints, such as genotoxicity; therefore, there is an urgent need to understand the xenobiotic metabolizing capacities of human skin and to compare these activities with reconstructed 3D skin models developed to replace animal testing. We have measured Phase I enzyme activities of cytochrome P450 (CYP) and cyclooxygenase (COX) in ex vivo human skin, the 3D skin model EpiDerm™ (EPI-200), immortalized keratinocyte-based cell lines and primary normal human epidermal keratinocytes. Our data demonstrate that basal CYP enzyme activities are very low in whole human skin and EPI-200 as well as keratinocytes. In addition, activities in monolayer cells differed from organotypic tissues after induction. COX activity was similar in skin, EPI-200 and NHEK cells, but was significantly lower in immortalized keratinocytes. Hence, the 3D model EPI-200 might represent a more suitable model for dermatotoxicological studies. Altogether, these data help to better understand skin metabolism and expand the knowledge of in vitro alternatives used for dermatotoxicity testing.

Role of Dlg5/lp-dlg, a membrane-associated guanylate kinase family protein, in epithelial-mesenchymal transition in LLc-PK1 renal epithelial cells

Discs large homolog 5 (Dlg5) is a member of the membrane-associated guanylate kinase adaptor family of proteins, some of which are involved in the regulation of epithelial-to-mesenchymal transition (EMT). Dlg5 has been described as a susceptibility gene for Crohn's disease; however, the physiological function of Dlg5 is unknown. We show here that transforming growth factor-β (TGF-β)-induced EMT suppresses Dlg5 expression in LLc-PK1 cells. Depletion of Dlg5 expression by knockdown promoted the expression of the mesenchymal marker proteins, fibronectin and α-smooth muscle actin, and suppressed the expression of E-cadherin. In addition, activation of JNK and p38, which are stimulated by TGF-β, was enhanced by Dlg5 depletion. Furthermore, inhibition of the TGF-β receptor suppressed the effects of Dlg5 depletion. These observations suggest that Dlg5 is involved in the regulation of TGF-βreceptor-dependent signals and EMT.

Potent anti-aging activity of Aruncus dioicus, a native plant of Ulleung-do, South Korea, in CCD-986sk fibroblasts via suppression of matrix metalloproteinases

Aruncus dioicus var. kamtschaticus HARA, also known as goat's beard, is a native plant in Ulleung-do, South Korea. It has been used as a remedy in skin care, detoxification, blood stanching, tonsillitis. High performance liquid chromatography with diode array detection was used for partial validation of bioactive chemicals in A. dioicus ethyl acetate (EtOAc) extract, and EtOAC extract was examined for its effect on ultraviolet (UV)-induced cell aging using CCD-986sk-human skin fibroblast cells. Cells were exposed to UV-B for 1 min before extract treatment. An established viability assay was performed to test cell toxicity of A. dioicus at 5, 10, or 50 μg/ml concentrations, and activities of matrix metalloproteinase (MMP) 1, 2, 3, phosphorylated-p38 (p-p38, an activated form of p38), p38, and c-fos transcription factors were evaluated. A. dioicus extract decreased the amount of mRNA transcripts and total proteins of MMP1, 2, 3 as well as p-p38 and c-fos. The c-fos expression was also confirmed by in vivo fluorescent staining of CCD-986sk cells after UV-B exposure followed by EtOAc extract treatment. The results showed that expression of skin aging related genes encoding MMP1, 2, and 3 was inhibited by reduced transcription factor expression of p-p38 and c-fos by A. dioicus EtOAc extract. The results suggest that A. dioicus extract can be used to reduce UV-B-induced skin aging and is a potential candidate for cosmedical materials.

Regulation of ubiquitination-mediated protein degradation by survival kinases in cancer

The ubiquitin–proteasome system is essential for multiple physiological processes via selective degradation of target proteins and has been shown to plays a critical role in human cancer. Activation of oncogenic factors and inhibition of tumor suppressors have been shown to be essential for cancer development, and protein ubiquitination has been linked to the regulation of oncogenic factors and tumor suppressors. Three kinases, AKT, extracellular signal-regulated kinase, and IκB kinase, we refer to as oncokinases, are activated in multiple human cancers. We and others have identified several key downstream targets that are commonly regulated by these oncokinases, some of which are regulated directly or indirectly via ubiquitin-mediated proteasome degradation, including FOXO3, β-catenin, myeloid cell leukemia-1, and Snail. In this review, we summarize these findings from our and other groups and discuss potential future studies and applications in the clinic.

MC1R variant allele effects on UVR-induced phosphorylation of p38, p53, and DDB2 repair protein responses in melanocytic cells in culture

Variant alleles of the human melanocortin 1 receptor (MC1R) reduce the ability of melanocytes to produce the dark pigment eumelanin, with R alleles being most deficient. Cultured melanocytes of MC1R R/R variant genotype give reduced responses to [Nle(4), D-Phe(7)]α-melanocyte-stimulating hormone (NDP-MSH) ligand stimulation and lower levels of DNA repair than MC1R wild-type strains. p38 controls xeroderma pigmentosum (XP)-C recruitment to DNA damage sites through regulating ubiquitylation of the DNA damage-binding protein 2 (DDB2) protein, and p53 is implicated in the nuclear excision repair process through its regulation of XP-C and DDB2 protein expression. We report the effects of MC1R ligand treatment and UVR exposure on phosphorylation of p38 and p53, and DDB2 protein expression in MC1R variant strains. Wild-type MC1R melanocyte strains grown together with keratinocytes in coculture, when treated with NDP-MSH and exposed to UVR, gave synergistic activation of p38 and p53 phosphorylation, and were not replicated by R/R variant melanocytes, which have lower basal levels of phosphorylated forms of p38. Minor increases in p38 phosphorylation status in R/R variant melanocyte cocultures could be attributed to the keratinocytes alone. We also found that MC1R wild-type strains regulate DDB2 protein levels through p38, but MC1R R/R variant melanocytes do not. This work confirms the important functional role that the MC1R receptor plays in UVR stress-induced DNA repair.

c-Jun-N-Terminal Kinase Signaling Is Involved in Cyclosporine-Induced Epithelial Phenotypic Changes

Tubular epithelial cells play a central role in the pathogenesis of chronic nephropathies. Previous toxicogenomic studies have demonstrated that cyclosporine- (CsA-) induced epithelial phenotypic changes (EPCs) are reminiscent of an incomplete epithelial to mesenchymal transition (EMT) in a TGF-β-independent manner. Furthermore, we identified endoplasmic reticulum (ER) stress as a potential mechanism that may participate in the modulation of tubular cell plasticity during CsA exposure. Because c-jun-N-terminal kinase (JNK), which is activated during ER stress, is implicated in kidney fibrogenesis, we undertook the current study to identify the role of JNK signaling in EPCs induced by CsA. In primary cultures of human renal epithelial cells, CsA activates JNK signaling, and the treatment with a JNK inhibitor reduces the occurrence of cell shape changes, E-cadherin downregulation, cell migration, and Snail-1 expression. Our results suggest that CsA activates JNK signaling, which, in turn, may participate in the morphological alterations through the regulation of Snail-1 expression.

Ageing skin: oestrogen receptor β agonists offer an approach to change the outcome

Oestrogen (17β estradiol) and the dietary antioxidants resveratrol, genistein and S-equol, an isoflavone produced from the gut biotransformation of soy daidzein, are effective agents to reduce ageing in skin. It is widely held that these antioxidants scavenge free radicals to prevent skin damage. However, the evidence to date suggests that the primary mechanism of action of these antioxidants is to activate oestrogen receptor β (ERβ), which in turn enhances the expression of antioxidant enzymes and inhibits the expression of snail, a transcription factor that regulates keratinocyte cell proliferation and migration. Based on their selectivity, ERβ agents provide a treatment option for ageing skin without the potential safety issues associated with oestrogen therapy.