The inhibition of invasion of human melanoma cells through N-cadherin knock-down

Impact of Rab27 on Melanoma Cell Invasion and sEV Secretion

The migratory and invasive capabilities of melanoma cells contribute to metastasis. Therefore, targeting the genes driving these processes can support melanoma therapy. Rab27A and Rab27B contribute to tumor formation progression in many types of cancer through various mechanisms, including the secretion of small extracellular vesicles (sEVs). We explored the role of these GTPases in melanoma cell functioning in three RAB27A knockout (KO) cell lines (A375, DMBC12, and SkMel28) and a double RAB27A/B KO A375 cell line. The loss of RAB27A impaired the migration and invasion of DMBC12 and SkMel28 cells; however, the behavior of highly aggressive A375 cells was unaffected. The RAB27A/B double knockout moderately decreased the migratory capacity of A375 cells without disturbing their invasiveness. Additionally, the silencing of RAB27A did not affect the number and mean size of the sEVs, despite some alterations in the protein content of the vesicles. Both Rab27 isoforms can, at least partially, act independently. The potential role of Rab27A in the functioning of melanoma cells depends on the individual character of the cell line, but not on its basal expression, and seems to be unrelated to the secretion of sEVs.

Proteomics and Bioinformatics Identify Drug-Resistant-Related Genes with Prognostic Potential in Cholangiocarcinoma

Drug resistance is a major challenge in the treatment of advanced cholangiocarcinoma (CCA). Understanding the mechanisms of drug resistance can aid in identifying novel prognostic biomarkers and therapeutic targets to improve treatment efficacy. This study established 5-fluorouracil- (5-FU) and gemcitabine-resistant CCA cell lines, KKU-213FR and KKU-213GR, and utilized comparative proteomics to identify differentially expressed proteins in drug-resistant cells compared to parental cells. Additionally, bioinformatics analyses were conducted to explore the biological and clinical significance of key proteins. The drug-resistant phenotypes of KKU-213FR and KKU-213GR cell lines were confirmed. In addition, these cells demonstrated increased migration and invasion abilities. Proteomics analysis identified 81 differentially expressed proteins in drug-resistant cells, primarily related to binding functions, biological regulation, and metabolic processes. Protein-protein interaction analysis revealed a highly interconnected network involving MET, LAMB1, ITGA3, NOTCH2, CDH2, and NDRG1. siRNA-mediated knockdown of these genes in drug-resistant cell lines attenuated cell migration and cell invasion abilities and increased sensitivity to 5-FU and gemcitabine. The mRNA expression of these genes is upregulated in CCA patient samples and is associated with poor prognosis in gastrointestinal cancers. Furthermore, the functions of these proteins are closely related to the epithelial-mesenchymal transition (EMT) pathway. These findings elucidate the potential molecular mechanisms underlying drug resistance and tumor progression in CCA, providing insights into potential therapeutic targets.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

YAP1 controls the N-cadherin-mediated tumor-stroma interaction in melanoma progression

The hallmark of epithelial-to-mesenchymal transition (EMT) is the switch from epithelial cadherin (E-cadherin) to neural cadherin (N-cadherin), allowing melanoma cells to form a homotypic N-cadherin-mediated adhesion with stromal fibroblasts. However, how cadherin switching is initiated, maintained, and regulated in melanoma remains elusive. Here, we report a novel mechanism underlying cadherin switching in melanoma cells that is regulated by stromal Yes-associated protein 1 (YAP1) signaling. The progression of a BRAF-mutant mouse melanoma was suppressed in vivo upon YAP1 ablation in cancer-associated fibroblasts (CAFs). On the contrary, overexpressing YAP1 in CAFs accelerated melanoma development. By RNA-Seq, N-cadherin was identified as a major downstream effector of YAP1 signaling in CAFs. YAP1 silencing reduced N-cadherin expression in CAFs, leading to the downregulation of N-cadherin in neighboring melanoma cells. N-cadherin ablation inhibited the PI3K-AKT signaling pathway in melanoma cells and melanoma cell proliferation. The findings suggest that YAP1 depletion in CAFs induces the downregulation of p-AKT signaling in melanoma cells through the N-cadherin-mediated interaction between melanoma cells and CAFs. The data underscore an important role of CAFs in regulating N-cadherin-mediated adhesion and signaling in melanoma and highlight that disentangling cadherin-mediated cell-cell interactions can potentially disrupt tumor-stroma interactions and reverse the tumor cell invasive phenotype.

Role of PLK1/NUMB/NOTCH in epithelial-mesenchymal transition in human melanoma

Polo-like kinase 1 (PLK1), a serine/threonine kinase, is overexpressed in melanoma and its expression has been associated with poor disease prognosis. PLK1 has been shown to interact with NUMB, a NOTCH antagonist. However, the exact role of PLK1, NUMB, and NOTCH signaling in epithelial-mesenchymal transition (EMT) in melanoma progression is unclear. In this study, Affymetrix microarray analysis was performed to determine differentially expressed genes following shRNA-mediated knockdown of PLK1 in human melanoma cells that showed significant modulations in EMT and metastasis-related genes. Using multiple PLK1-modulated melanoma cell lines, we found that PLK1 is involved in the regulation of cell migration, invasion, and EMT via its kinase activity and NOTCH activation. In vitro kinase assay and mass spectrometry analysis demonstrated a previously unknown PLK1 phosphorylation site (Ser413) on NUMB. Overexpression of non-phosphorylatable (S413A) and phosphomimetic (S413D) mutants of NUMB in melanoma cells implicated the involvement of NUMB-S413 phosphorylation in cell migration and invasion, which was independent of NOTCH activation. To determine the clinical relevance of these findings, immunohistochemistry was performed using melanoma tissue microarray, which indicated a strong positive correlation between PLK1 and N-cadherin, a protein required for successful EMT. These findings were supported by TCGA analysis, where expression of high PLK1 with low NUMB or high NOTCH or N-cadherin showed a significant decrease in survival of melanoma patients. Overall, these results suggest a potential role of PLK1 in EMT, migration, and invasion of melanoma cells. Our findings support the therapeutic targeting of PLK1, NUMB, and NOTCH for melanoma management.

Three generations of mTOR kinase inhibitors in the activation of the apoptosis process in melanoma cells

Many signaling pathways are involved in the mammalian target of rapamycin (mTOR), and this serine/threonine kinase regulates the most important cellular processes such as cell proliferation, autophagy, and apoptosis. The subject of this research was the effect of protein kinase inhibitors involved in the AKT, MEK, and mTOR kinase signaling pathways on the expression of pro-survival proteins, activity of caspase-3, proliferation, and induction of apoptosis in melanoma cells. The following inhibitors were used: protein kinase inhibitors such as AKT-MK-2206, MEK-AS-703026, mTOR-everolimus and Torkinib, as well as dual PI3K and mTOR inhibitor-BEZ-235 and Omipalisib, and mTOR1/2-OSI-027 inhibitor in single-mode and their combinations with MEK1/2 kinase inhibitor AS-703026. The obtained results confirm the synergistic effect of nanomolar concentrations of mTOR inhibitors, especially the dual PI3K and mTOR inhibitors (Omipalisib, BEZ-235) in combination with the MAP kinase inhibitor (AS-703026) in the activation of caspase 3, induction of apoptosis, and inhibition of proliferation in melanoma cell lines. Our previous and current studies confirm the importance of the mTOR signal transduction pathway in the neoplastic transformation process. Melanoma is a case of a very heterogeneous neoplasm, which causes great difficulties in treating this neoplasm in an advanced stage, and the standard approach to this topic does not bring the expected results. There is a need for research on the search for new therapeutic strategies aimed at particular groups of patients. Effect of three generations of mTOR kinase inhibitors on caspase-3 activity, apoptosis and proliferation in melanoma cell lines.

YAP1 controls the N-cadherin-mediated tumor-stroma interaction in melanoma progression

Epithelial-to-mesenchymal transition (EMT) is crucial for melanoma cells to escape keratinocyte control, invade underlying dermal tissues, and metastasize to distant organs. The hallmark of EMT is the switch from epithelial cadherin (E-cadherin) to neural cadherin (N-cadherin), allowing melanoma cells to form a homotypic N-cadherin-mediated adhesion with stromal fibroblasts. However, how "cadherin switching" is initiated, maintained, and regulated in melanoma remains unknown. Here, we show that upon Yes-associated protein 1 (YAP1) ablation in cancer-associated fibroblasts (CAFs), the progression of a BRAF-mutant mouse melanoma was significantly suppressed in vivo, and overexpressing YAP1 in CAFs accelerated melanoma growth. CAFs require the YAP1 function to proliferate, migrate, remodel the cytoskeletal machinery and matrix, and promote cancer cell invasion. By RNA-Seq, N-cadherin was identified as a major downstream effector of YAP1 signaling in CAFs. YAP1 silencing led to N-cadherin downregulation in CAFs, which subsequently induced the downregulation of N-cadherin in neighboring melanoma cells. N-cadherin downregulation inhibited the PI3K-AKT signaling pathway in melanoma cells and suppressed melanoma growth in vivo, supporting the role of N-cadherin as an adhesive and signaling molecule in melanoma cells. This finding suggests that YAP1 depletion in CAFs induces the downregulation of p-AKT signaling in melanoma cells through the N-cadherin-mediated interaction between melanoma cells and CAFs. Importantly, our data underscore that CAFs can regulate N-cadherin-mediated interactions with melanoma cells. Thus, disentangling cadherin-mediated cell-cell interactions can potentially disrupt tumor-stroma interactions and reverse the tumor cell invasive phenotype.

YAP Activation in Promoting Negative Durotaxis and Acral Melanoma Progression

Directed cell migration towards a softer environment is called negative durotaxis. The mechanism and pathological relevance of negative durotaxis in tumor progression still requires in-depth investigation. Here, we report that YAP promotes the negative durotaxis of melanoma. We uncovered that the RhoA-myosin II pathway may underlie the YAP enhanced negative durotaxis of melanoma cells. Acral melanoma is the most common subtype of melanoma in non-Caucasians and tends to develop in a stress-bearing area. We report that acral melanoma patients exhibit YAP amplification and increased YAP activity. We detected a decreasing stiffness gradient from the tumor to the surrounding area in the acral melanoma microenvironment. We further identified that this stiffness gradient could facilitate the negative durotaxis of melanoma cells. Our study advanced the understanding of mechanical force and YAP in acral melanoma and we proposed negative durotaxis as a new mechanism for melanoma dissemination.

C-phycocyanin decreases proliferation and migration of melanoma cells: In silico and in vitro evidences

The incidence and number of deaths caused by melanoma have been increasing in recent years, and the pigment C-phycocyanin (C-PC) appears as a possible alternative to treat this disease. So, the objective of this study was to combine in silico and in vitro analysis to understand the main anti-melanoma pathways exerted by C-PC. We evaluated the ability of C-PC to bind to the main cellular targets related in the progression of melanoma through molecular docking, and the reflection of this bind in the biological effects in the B16F10 cell line through in vitro analysis. Our results showed that C-PC was able to bind BRAF and MEK, which are related to the signal transduction pathway for proliferation and survival. There was also an interaction between C-PC and cyclin-dependent kinase 4 and 6. In vitro analysis demonstrated that C-PC decreased B16F10 cell proliferation, as observed by cell viability and mitotic index assays. C-PC also interacted with matrix metalloproteinase 2 and 9 and N-cadherin, which may have caused the decrease in cell migration observed in vitro. Besides that, C-PC interacts with VEGF, a factor responsible for regulating the proliferation and cellular invasion pathways. Finally, C-PC did not alter the cell viability of the non-tumoral melanocytes. Therefore, C-PC is a strong anti-tumor candidate for the treatment of melanoma, since it acts in different cellular pathways of melanoma, without causing damage to non-tumoral cells.

A Nuclear-Directed Ribonuclease Variant Targets Cancer Stem Cells and Inhibits Migration and Invasion of Breast Cancer Cells

Simple Summary

During the past decades the achievements made in treating cancers have significantly improved the survival of patients. However, cancer is still one of the leading causes of mortality. It is suggested that treatment failure is mediated by a subpopulation of tumor cells named cancer stem cells that can survive after treatment and promote cancer relapse. Targeting these cells is important to improve cancer therapy. The aim of our study is to determine the effect of a human ribonuclease variant on breast cancer cells grown in 3D and on cancer stem cells. Moreover, we study its effect on the ability of breast cancer cells to migrate and produce metastasis, responsible for about 90% of cancer deaths. We show that this ribonuclease arrests tumor cells grown in 3D without affecting normal breast cells, and this significantly inhibits cancer stem cell development. Additionally, it reduces the migratory and invasive capacities of tumor cells.

Abstract

Despite the significant advances in cancer research made in recent years, this disease remains one of the leading causes of death worldwide. In part, this is due to the fact that after therapy, a subpopulation of self-renewing tumor cells can survive and promote cancer relapse, resistance to therapies and metastasis. Targeting these cancer stem cells (CSCs) is therefore essential to improve the clinical outcome of cancer patients. In this sense, multi-targeted drugs may be promising agents targeting CSC-associated multifocal effects. We have previously constructed different human pancreatic ribonuclease (RNase) variants that are cytotoxic for tumor cells due to a non-classical nuclear localization signal introduced in their sequence. These cytotoxic RNases affect the expression of multiple genes involved in deregulated metabolic and signaling pathways in cancer cells and are highly cytotoxic for multidrug-resistant tumor cell lines. Here, we show that these cytotoxic nuclear-directed RNases are highly selective for tumor cell lines grown in 3D, inhibit CSCs’ development and diminish the self-renewal capacity of the CSCs population. Moreover, these human RNase variants reduce the migration and invasiveness of highly invasive breast cancer cells and downregulate N-cadherin expression.

Cell Adhesion Molecules in Normal Skin and Melanoma

Cell adhesion molecules (CAMs) of the cadherin, integrin, immunoglobulin, and selectin protein families are indispensable for the formation and maintenance of multicellular tissues, especially epithelia. In the epidermis, they are involved in cell–cell contacts and in cellular interactions with the extracellular matrix (ECM), thereby contributing to the structural integrity and barrier formation of the skin. Bulk and single cell RNA sequencing data show that >170 CAMs are expressed in the healthy human skin, with high expression levels in melanocytes, keratinocytes, endothelial, and smooth muscle cells. Alterations in expression levels of CAMs are involved in melanoma propagation, interaction with the microenvironment, and metastasis. Recent mechanistic analyses together with protein and gene expression data provide a better picture of the role of CAMs in the context of skin physiology and melanoma. Here, we review progress in the field and discuss molecular mechanisms in light of gene expression profiles, including recent single cell RNA expression information. We highlight key adhesion molecules in melanoma, which can guide the identification of pathways and strategies for novel anti-melanoma therapies.

BACH1 promotes the progression of esophageal squamous cell carcinoma by inducing the epithelial-mesenchymal transition and angiogenesis

Metastasis to regional lymph nodes or distal organs predicts the progression of the disease and poor prognosis in esophageal squamous cell carcinoma (ESCC). Previous studies demonstrated that BTB and CNC homology 1 (BACH1) participates in various types of tumor metastasis. However, the function of BACH1 in ESCC was rarely reported. The present study demonstrated that BACH1 protein was overexpressed in ESCC tissues compared with paired esophageal epithelial tissues according to immunohistochemical staining (IHC). Higher levels of BACH1 mRNA were associated with decreased overall survival (OS) and shorter disease‐free survival (DFS) of ESCC patients based on an analysis of The Cancer Genome Atlas (TCGA) datasets. BACH1 significantly enhanced the migration and invasion of ESCC in vitro. Mechanistically, BACH1 promoted the epithelial–mesenchymal transition (EMT) by directly activating the transcription of CDH2, SNAI2, and VIM, as determined by chromatin immunoprecipitation‐quantitative polymerase chain reaction (ChIP‐qPCR). BACH1 overexpression significantly enhanced CDH2 promoter activity according to the results of a luciferase assay. The results of subsequent experiments indicated that BACH1 enhanced the growth of tumor xenografts. The density of CD31⁺ blood vessels and the expression of vascular endothelial growth factor C (VEGFC) in tumor xenografts were significantly associated with BACH1 levels according to the results of IHC and immunofluorescence (IF) analyses performed in vivo. Moreover, ChIP‐qPCR analysis demonstrated that the transcriptional activity of VEGFC was also upregulated by BACH1. Thus, BACH1 contributes to ESCC metastasis and tumorigenesis by partially facilitating the EMT and angiogenesis, and BACH1 may be a promising therapeutic target or molecular marker in ESCC.

Screening and identification of potential biomarkers and therapeutic drugs in melanoma via integrated bioinformatics analysis

Melanoma is a highly aggressive malignant skin tumor with a high rate of metastasis and mortality. In this study, a comprehensive bioinformatics analysis was used to clarify the hub genes and potential drugs. Download the GSE3189, GSE22301, and GSE35388 microarray datasets from the Gene Expression Omnibus (GEO), which contains a total of 33 normal samples and 67 melanoma samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) approach analyze DEGs based on the DAVID. Use STRING to construct protein-protein interaction network, and use MCODE and cytoHubba plug-ins in Cytoscape to perform module analysis and identified hub genes. Use Gene Expression Profile Interactive Analysis (GEPIA) to assess the prognosis of genes in tumors. Finally, use the Drug-Gene Interaction Database (DGIdb) to screen targeted drugs related to hub genes. A total of 140 overlapping DEGs were identified from the three microarray datasets, including 59 up-regulated DEGs and 81 down-regulated DEGs. GO enrichment analysis showed that these DEGs are mainly involved in the biological process such as positive regulation of gene expression, positive regulation of cell proliferation, positive regulation of MAP kinase activity, cell migration, and negative regulation of the apoptotic process. The cellular components are concentrated in the membrane, dendritic spine, the perinuclear region of cytoplasm, extracellular exosome, and membrane raft. Molecular functions include protein homodimerization activity, calmodulin-binding, transcription factor binding, protein binding, and cytoskeletal protein binding. KEGG pathway analysis shows that these DEGs are mainly related to protein digestion and absorption, PPAR signaling pathway, signaling pathways regulating stem cells' pluripotency, and Retinol metabolism. The 23 most closely related DEGs were identified from the PPI network and combined with the GEPIA prognostic analysis, CDH3, ESRP1, FGF2, GBP2, KCNN4, KIT, SEMA4D, and ZEB1 were selected as hub genes, which are considered to be associated with poor prognosis of melanoma closely related. Besides, ten related drugs that may have therapeutic effects on melanoma were also screened. These newly discovered genes and drugs provide new ideas for further research on melanoma.

Screening and identification of key genes and pathways in metastatic uveal melanoma based on gene expression using bioinformatic analysis

The current study aimed to elucidate the molecular mechanisms and identify the potential key genes and pathways for metastatic uveal melanoma (UM) using bioinformatics analysis.Gene expression microarray data from GSE39717 included 39 primary UM tissue samples and 2 metastatic UM tissue samples. Differentially expressed genes (DEGs) were generated using Gene Expression Omnibus 2R. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the online Database for Annotation, Visualization and Integrated Discovery (DAVID) tool. The web-based STRING tool was adopted to construct a protein--protein interaction (PPI) network. The MCODE tool in Cytoscape was used to generate significant modules of the PPI network.A total of 213 DEGs were identified. GO and KEGG analyses revealed that the upregulated genes were mainly enriched in extracellular matrix organization and blood coagulation cascades, while the downregulated DEGs were mainly related to protein binding, negative regulation of ERK cascade, nucleus and chromatin modification, and lung and renal cell carcinoma. The most significant module was extracted from the PPI network. GO and KEGG enrichment analyses of the module revealed that the genes were mainly enriched in the extracellular region and space organization, blood coagulation process, and PI3K-Akt signaling pathway. Hub genes, including FN1, APOB, F2, SERPINC1, SERPINA1, APOA1, FGG, PROC, ITIH2, VCAN, TFPI, CXCL8, CDH2, and HP, were identified from DEGs. Survival analysis and hierarchical clustering results revealed that most of the hub genes were associated with prognosis and clinical progression.Results of this bioinformatics analysis may provide predictive biomarkers and potential candidate therapeutic targets for individuals with metastatic UM.

Role of Cadherins in Cancer-A Review

Cadherins play an important role in tissue homeostasis, as they are responsible for cell-cell adhesion during embryogenesis, tissue morphogenesis, differentiation and carcinogenesis. Cadherins are inseparably connected with catenins, forming cadherin-catenin complexes, which are crucial for cell-to-cell adherence. Any dysfunction or destabilization of cadherin-catenin complex may result in tumor progression. Epithelial mesenchymal transition (EMT) is a mechanism in which epithelial cadherin (E-cadherin) expression is lost during tumor progression. However, during tumorigenesis, many processes take place, and downregulation of E-cadherin, nuclear β-catenin and p120 catenin (p120) signaling are among the most critical. Additional signaling pathways, such as Receptor tyrosine kinase (RTK), Rho GTPases, phosphoinositide 3-kinase (PI3K) and Hippo affect cadherin cell-cell adhesion and also contribute to tumor progression and metastasis. Many signaling pathways may be activated during tumorigenesis; thus, cadherin-targeting drugs seem to limit the progression of malignant tumor. This review discusses the role of cadherins in selected signaling mechanisms involved in tumor growth. The clinical importance of cadherin will be discussed in cases of human and animal cancers.

Cutaneous melanoma dissemination is dependent on the malignant cell properties and factors of intercellular crosstalk in the cancer microenvironment (Review)

The incidence of cutaneous malignant melanoma has been steadily increasing worldwide for several decades. This phenomenon seems to follow the trend observed in many types of malignancies caused by multiple significant factors, including ageing. Despite the progress in cutaneous malignant melanoma therapeutic options, the curability of advanced disease after metastasis represents a serious challenge for further research. In this review, we summarise data on the microenvironment of cutaneous malignant melanoma with emphasis on intercellular signalling during the disease progression. Malignant melanocytes with features of neural crest stem cells interact with non‑malignant populations within this microenvironment. We focus on representative bioactive factors regulating this intercellular crosstalk. We describe the possible key factors and signalling cascades responsible for the high complexity of the melanoma microenvironment and its premetastatic niches. Furthermore, we present the concept of melanoma early becoming a systemic disease. This systemic effect is presented as a background for the new horizons in the therapy of cutaneous melanoma.

Inhibiting Matrix Metalloproteinase-2 Activation by Perturbing Protein-Protein Interactions Using a Cyclic Peptide

We report on a cyclic peptide that inhibits matrix metalloproteinase-2 (MMP2) activation with a low-nM-level potency. This inhibitor specifically binds to the D₅₇₀-A₅₈₃ epitope on proMMP2 and interferes with the protein-protein interaction (PPI) between proMMP2 and tissue inhibitor of metalloproteinases-2 (TIMP2), thereby preventing the TIMP2-assisted proMMP2 activation process. We developed this cyclic peptide inhibitor through an epitope-targeted library screening process and validated its binding to proMMP2. Using a human melanoma cell line, we demonstrated the cyclic peptide's ability to modulate cellular MMP2 activities and inhibit cell migration. These results provide the first successful example of targeting the PPI between proMMP2 and TIMP2, confirming the feasibility of an MMP2 inhibition strategy that has been sought after for 2 decades.

Integrin linked kinase regulates endosomal recycling of N-cadherin in melanoma cells

Malignant transformation is characterized by a phenotype "switch" from E- to N-cadherin - a major hallmark of epithelial to mesenchymal transition (EMT). The increased expression of N-cadherin is commonly followed by a growing capacity for migration as well as resistance to apoptosis. Integrin Linked Kinase (ILK) is a key molecule involved in EMT and progression of cancer cells. ILK is known as a major signaling mediator involved in cadherin switch, but the specific mechanism through which ILK modulates N-cadherin expression is still not clear. Studies were carried out on human melanoma WM793 and 1205Lu cell lines. Expression of proteins was analyzed using PCR and Western Blot; siRNA transfection was done for ILK. Analysis of cell signaling pathways was monitored with phospho-specific antibodies. Subcellular localization of protein was studied using the ProteoExtract Subcellular Kit and Western blot analysis. Our data show that ILK knockdown by siRNA did suppress N-cadherin expression in melanoma, but only at the protein level. The ILK silencing-induced decrease of N-cadherin membranous expression in melanoma highlights the likely crucial role of ILK in the coordination of membrane trafficking through alteration of Rab expression. It is essential to understand the molecular mechanism of increased N-cadherin expression in cancer to possibly use it in the search of new therapeutic targets.

LncRNA MEG3 promotes melanoma growth, metastasis and formation through modulating miR-21/E-cadherin axis

Background

Melanoma is the most aggressive type of skin cancer with high mortality rate and poor prognosis. lncRNA MEG3, a tumor suppressor, is closely related to the development of various cancers. However, the role of lncRNA MEG3 in melanoma has seldom been studied.

Methods

RT-PCR was used to examine the expressions of lncRNA MEG3 and E-cadherin in melanoma patients and cell lines. Then, the biological functions of lncRNA MEG3 and E-cadherin were demonstrated by transfecting lncRNA MEG3-siRNA, lncRNA MEG3-overexpression, E-cadherin-siRNA and E-cadherin-overexpression plasmids in melanoma cell lines. Moreover, CCK8 assay and colony formation assay were utilized to assess the cell proliferation; Transwell assay was performed to evaluate the cell invasive ability; and tumor xenografts in nude mice were applied to test the tumor generation. Additionally, the target interactions among lncRNA MEG3, miR-21 and E-cadherin were determined by dual luciferase reporter assay. Finally, RT-PCR and WB were further conducted to verify the regulatory roles among lncRNA MEG3, miR-21 and E-cadherin.

Results

The clinical data showed that lncRNA MEG3 and E-cadherin expressions were both declined in carcinoma tissues as compared with their para-carcinoma tissues. Moreover, lncRNA MEG3 and E-cadherin expressions in B16 cells were also higher than those in A375 and A2058 cells. Subsequently, based on the differently expressed lncRNA MEG3 and E-cadherin in these human melanoma cell lines, we chose B16, A375 and A2058 cells for the following experiments. The results demonstrated that lncRNA MEG3 could suppress the tumor growth, tumor metastasis and formation; and meanwhile E-cadherin had the same effects on tumor growth, tumor metastasis and formation. Furthermore, the analysis of Kaplan–Meier curves also confirmed that there was a positive correlation between lncRNA MEG3 and E-cadherin. Ultimately, dual luciferase assays were further used to verify that lncRNA MEG3 could directly target miR-21 which could directly target E-cadherin in turn. Additionally, the data of RT-PCR and WB revealed that knockdown of lncRNA MEG3 in B16 cells inhibited miR-21 expression and promoted E-cadherin expression, but overexpression of lncRNA MEG3 in A375 and A2058 cells presented completely opposite results.

Conclusion

Our findings indicated that lncRNA MEG3 might inhibit the tumor growth, tumor metastasis and formation of melanoma by modulating miR-21/E-cadherin axis.

Identification of a five-miRNA signature predicting survival in cutaneous melanoma cancer patients

Background

Cutaneous melanoma (CM) is the deadliest form of skin cancer. Numerous studies have revealed that microRNAs (miRNAs) are expressed abnormally in melanoma tissues. Our work aimed to assess multiple miRNAs using bioinformatic analysis in order to predict the prognoses of cutaneous melanoma patients.

Methods

The microarray dataset GSE35579 was downloaded from the Gene Expression Omnibus (GEO) database to detect the differential expression of miRNAs (DEMs), including 41 melanoma (primary and metastatic) tissues and 11 benign nevi. Clinical information and miRNA sequencing data of cutaneous melanoma tissues were downloaded from the Cancer Genome Atlas database (TCGA) to assess the prognostic values of DEMs. Additionally, the target genes of DEMs were anticipated using miRanda, miRmap, TargetScan, and PicTar. Finally, functional analysis was performed using selected target genes on the Annotation, Visualization and Integrated Discovery (DAVID) website.

Results

After performing bioinformatic analysis, a total of 185 DEMs were identified: 80 upregulated miRNAs and 105 downregulated miRNAs. A five-miRNA (miR-25, miR-204, miR-211, miR-510, miR-513c) signature was discovered to be a potential significant prognostic biomarker of cutaneous melanoma when using the Kaplan–Meier survival method (P = 0.001). Univariate and multivariate Cox regression analyses showed that the five-miRNA signature could be an independent prognostic marker (HR = 0.605, P = 0.006) in cutaneous melanoma patients. Biological pathway analysis indicated that the target genes may be involved in PI3K-Akt pathways, ubiquitin-mediated proteolysis, and focal adhesion.

Conclusion

The identified five-miRNA signature may serve as a prognostic biomarker, or as a potential therapeutic target, in cutaneous melanoma patients.

mTOR inhibitor everolimus reduces invasiveness of melanoma cells

The mammalian target of rapamycin (mTOR) plays a key role in several cellular processes: proliferation, survival, invasion, and angiogenesis, and therefore, controls cell behavior both in health and in disease. Dysregulation of the mTOR signaling is involved in some of the cancer hallmarks, and thus the mTOR pathway is an important target for the development of a new anticancer therapy. The object of this study is recognition of the possible role of mTOR kinase inhibitors—everolimus single and in combination with selected downstream protein kinases inhibitors: LY294002 (PI3 K), U0126 (ERK1/2), GDC-0879 (B-RAF), AS-703026 (MEK), MK-2206 (AKT), PLX-4032 (B-RRAF) in cell invasion in malignant melanoma. Treatment of melanoma cells with everolimus led to a significant decrease in the level of both phosphorylated: mTOR (Ser2448) and mTOR (Ser2481) as well as their downstream effectors. The use of protein kinase inhibitors produced a significant decrease in metalloproteinases (MMPs) activity, as well as diminished invasion, especially when used in combination. The best results in the inhibition of both MMPs and cell invasiveness were obtained for the combination of an mTOR inhibitor— everolimus with a B-RAF inhibitor—PLX-4032. Slightly less profound reduction of invasiveness was obtained for the combinations of an mTOR inhibitor—everolimus with ERK1/2 inhibitor—U126 or MEK inhibitor—AS-703026 and in the case of MMPs activity decrease for PI3 K inhibitor—LY294002 and AKT inhibitor—MK-2206. The simultaneous use of everolimus or another new generation rapalog with selected inhibitors of crucial signaling kinases seems to be a promising concept in cancer treatment.

De Novo Pathogenic Variants in N-cadherin Cause a Syndromic Neurodevelopmental Disorder with Corpus Collosum, Axon, Cardiac, Ocular, and Genital Defects

Cadherins constitute a family of transmembrane proteins that mediate calcium-dependent cell-cell adhesion. The extracellular domain of cadherins consists of extracellular cadherin (EC) domains, separated by calcium binding sites. The EC interacts with other cadherin molecules in cis and in trans to mechanically hold apposing cell surfaces together. CDH2 encodes N-cadherin, whose essential roles in neural development include neuronal migration and axon pathfinding. However, CDH2 has not yet been linked to a Mendelian neurodevelopmental disorder. Here, we report de novo heterozygous pathogenic variants (seven missense, two frameshift) in CDH2 in nine individuals with a syndromic neurodevelopmental disorder characterized by global developmental delay and/or intellectual disability, variable axon pathfinding defects (corpus callosum agenesis or hypoplasia, mirror movements, Duane anomaly), and ocular, cardiac, and genital anomalies. All seven missense variants (c.1057G>A [p.Asp353Asn]; c.1789G>A [p.Asp597Asn]; c.1789G>T [p.Asp597Tyr]; c.1802A>C [p.Asn601Thr]; c.1839C>G [p.Cys613Trp]; c.1880A>G [p.Asp627Gly]; c.2027A>G [p.Tyr676Cys]) result in substitution of highly conserved residues, and six of seven cluster within EC domains 4 and 5. Four of the substitutions affect the calcium-binding site in the EC4-EC5 interdomain. We show that cells expressing these variants in the EC4-EC5 domains have a defect in cell-cell adhesion; this defect includes impaired binding in trans with N-cadherin-WT expressed on apposing cells. The two frameshift variants (c.2563_2564delCT [p.Leu855Valfs^∗4]; c.2564_2567dupTGTT [p.Leu856Phefs^∗5]) are predicted to lead to a truncated cytoplasmic domain. Our study demonstrates that de novo heterozygous variants in CDH2 impair the adhesive activity of N-cadherin, resulting in a multisystemic developmental disorder, that could be named ACOG syndrome (agenesis of corpus callosum, axon pathfinding, cardiac, ocular, and genital defects).

SIRT2 Contributes to the Resistance of Melanoma Cells to the Multikinase Inhibitor Dasatinib

Malignant melanoma is the most aggressive skin cancer and can only be cured if detected early. Unfortunately, later stages of the disease do not guarantee success due to the rapid rate of melanoma cell metastasis and their high resistance to applied therapies. The search for new molecular targets and targeted therapy may represent the future in the development of effective methods for combating this cancer. SIRT2 is a promising target; thus, we downregulated SIRT2 expression in melanoma cells in vertical growth and metastatic phases and demonstrated that sirtuin acts as regulator of the basic functions of melanoma cells. A detailed transcriptomic analysis showed that SIRT2 regulates the expression of multiple genes encoding the tyrosine kinase pathways that are molecular targets of dasatinib. Indeed, cells with low SIRT2 expression were more susceptible to dasatinib, as demonstrated by multiple techniques, e.g., neutral red uptake, 3/7 caspase activity, colony formation assay, and in vitro scratch assay. Furthermore, these cells showed an altered phosphorylation profile for proteins playing roles in the response to dasatinib. Thus, our research indicates new, previously unknown SIRT2 functions in the regulation of gene expression, which is of key clinical significance.

mTOR inhibitor Everolimus-induced apoptosis in melanoma cells

Melanoma is the most aggressive, therapy-resistant skin cancer. The mammalian target of rapamycin (mTOR), the serine/threonine kinase which integrates both intracellular and extracellular signals, plays a crucial role in coordinating the balance between the growth and death of cells. The object of this study is a comparison of the influence of mTOR inhibitor everolimus in the concentration range between 20 nM and 10 μM, used individually and in combination with selected downstream protein kinases inhibitors: LY294002 (PI3K), U0126 (ERK1/2), AS-703026 (MEK) and MK-2206 (AKT) on the expression of pro-survival proteins: p-Bcl-2 (S70), p-Bcl-2 (T56), Bcl-2, Bcl-xL, Mcl-1, activity of caspase-3, proliferation and induction of apoptosis in melanoma cells. Current results clearly show that the nanomolar concentration of the mTOR inhibitor everolimus in combination with the inhibitor of MAP kinase (AS-703026) or AKT kinase (MK-2206) is effective in inducing apoptosis and reducing proliferation of melanoma cells. The herein research results confirm the hypothesis on the important role of mTOR signaling in cancer progression, and gives hope that implementation of successful combination of its inhibitors will find recognition and application in cancer treatment in the near future.

Itraconazole treatment of primary malignant melanoma of the vagina evaluated using positron emission tomography and tissue cDNA microarray: a case report

BACKGROUND

Primary malignant melanoma of the vagina is extremely rare, with a poorer prognosis than cutaneous malignant melanoma. Previous studies have explored the repurposing of itraconazole, a common oral anti-fungal agent, for the treatment of various cancers. Here, we describe a patient with metastatic, unresectable vaginal malignant melanoma treated with 200 mg oral itraconazole twice a day in a clinical window-of-opportunity trial.

CASE PRESENTATION

A 64-year-old Japanese woman with vaginal and inguinal tumours was referred to our institution. On the basis of an initial diagnosis of vaginal cancer metastatic to the inguinal lymph nodes, we treated her with itraconazole in a clinical trial until the biopsy and imaging study results were obtained. During this period, biopsies were performed three times, and 18F-fluoro-deoxyglucose positron emission tomography (FDG/PET)-computed tomography (CT) was performed twice. Biopsy results confirmed the diagnosis of primary malignant melanoma of the vagina. Imaging studies revealed metastases to multiple sites, including the brain, for which she underwent gamma-knife radiosurgery. During the window period before nivolumab initiation, the patient received itraconazole for 30 days. Within a week of itraconazole initiation, pain in the inguinal nodes was ameliorated. PET-CT on days 6 and 30 showed a reduction in tumour size and FDG uptake, respectively. The biopsied specimens obtained on days 1, 13, and 30 were subjected to cDNA microarray analysis, which revealed a 100-fold downregulation in the transcription of four genes: STATH, EEF1A2, TTR, and CDH2. After 12 weeks of nivolumab administration, she developed progressive disease and grade 3 immune-related hepatitis. Discontinuation of nivolumab resulted in the occurrence of left pelvic and inguinal pain. Following re-challenge with itraconazole, the patient has not reported any pain for 4 months.

CONCLUSION

The findings of this case suggest that itraconazole is a potential effective treatment option for primary malignant melanoma of the vagina. Moreover, we identified potential itraconazole target genes, which could help elucidate the mechanism underlying this disease and potentially aid in the development of new therapeutic agents.