Melanoma Cell Invasion Research Articles

Itraconazole-Induced the Activation of Adenosine 5'-Monophosphate (Amp)-Activated Protein Kinase Inhibits Tumor Growth of Melanoma via Inhibiting ERK Signaling.

Itraconazole, an effective broad-spectrum antifungal drug, has been well established for its anticancer activity in cancers including melanoma. However, details concerning its underlying mechanism in melanoma are unclear. This work investigated the function of itraconazole-induced 5'-monophosphate (AMP)-activated protein kinase alpha (AMPKα) in melanoma progression through ERK signaling. The AMPKα level in melanoma tissues and cells was assessed by RT-qPCR and western blot. Survival analysis of patients with melanoma based on the AMPKα expression level was performed according to TCGA database. Melanoma cell proliferation, migration, and invasion were examined using CCK-8, colony formation, wound healing, and Transwell assays. A xenograft tumor model was established to examine the effect of itraconazole on tumor growth in vivo. The AMPKα mRNA and protein levels were reduced in melanoma tissues and cells. A low expression of AMPKα indicated a poor prognosis. Functionally, itraconazole restrained melanoma cell proliferation, migration, and invasion by upregulating AMPKα. Itraconazole activated AMPK signaling and inhibited ERK signaling in melanoma cells. Activation of ERK signaling reversed the effect of itraconazole on cellular process in melanoma. Moreover, itraconazole-induced AMPKα inhibited melanoma tumor growth in vivo by inhibiting ERK signaling. Itraconazole-induced AMPKα inhibits the progression of melanoma by inhibition of ERK signaling.

ERBB3 binding protein 1 promotes the progression of malignant melanoma through activation of the Wnt/ \u03b2-catenin signaling pathway

BackgroundMalignant melanoma (MM) is highly metastatic and has the highest mortality rate in patients with skin cancer. The ERBB3 binding protein 1 (Ebp1) has been linked to the onset and progression of a number of malignancies. However, the role of Ebp1 in MM has not yet been reported.MethodsMultiple databases were analyzed for comparing the expression of Ebp1 in normal skin and MM. Ebp1 expression was knocked down in A375 and B16 cells, and the impact of Ebp1 on the cell growth was tested by CCK-8, plate clone colony, and cell cycle assays. Scratch, transwell, and in vivo caudal vein lung metastasis tests were also used to confirm the effects of Ebp1 on melanoma cells migration, invasion, and metastasis. Furthermore, the possible molecular mechanism of Ebp1 was predicted by set enrichment analysis and verified by western blotting.ResultsEbp1 expression was substantially higher in MM than it was in normal skin, and Ebp1 was linked to the clinical stage and lymph node metastases of patients with MM. Knockdown of Ebp1 inhibited cell proliferation, migration, and invasion. In vivo experiments further verified that the knockdown of Ebp1 had an obvious inhibitory effect on lung metastasis in nude mice. Knockdown of Ebp1 reduced vimentin, N-cadherin, slug, and snail expression while increasing E-cadherin expression. Furthermore, knockdown of Ebp1 reduced the expression of β-catenin, as well as its downstream targets CyclinD1 and p-GSK3β; however, a Wnt/β-catenin agonist could reverse this effect.ConclusionEbp1 may promote the proliferation and metastasis of melanoma cells through activation of the Wnt/β-catenin pathway.Graphical

Alpha-Enolase (ENO1) Correlates with Invasiveness of Cutaneous Melanoma-An In Vitro and a Clinical Study.

Simple SummaryAlpha-enolase (ENO1) undergoes accentuated overexpression in several solid cancers, but little is known about its status in cutaneous melanoma. The aim of this study was to investigate the prognostic significance of ENO1 in surgical resections from melanoma patients and to assess its expression and enzymatic activity in several melanoma cell lines. In clinical analysis, the overexpression of ENO1 in melanoma cells was significantly correlated with advanced clinical stage, presence of metastases in regional lymph nodes, and shorter cancer-specific overall survival and disease-free survival. We also demonstrated high expression of ENO1 in melanoma cell lines compared with normal melanocytes. Our study, which extends previous in vitro research, makes the alpha-enolase a candidate for a promising diagnostic and therapeutic target for various types of cancers. Consequently, additional testing of ENO1 as a target for melanoma therapy is necessary.Alpha-enolase (ENO1) is a glycolytic metalloenzyme, and its overexpression occurs in numerous cancers, contributing to cancer cell survival, proliferation, and maintenance of the Warburg effect. Patients with an overexpression of ENO1 have a poor prognosis. The aim of the present study was to investigate the prognostic significance of ENO1 in surgical resections from 112 melanoma patients and to assess its expression and enzymatic activity in normoxia and hypoxia in several melanoma cell lines. Overexpression of ENO1 in tumor cells from patients was correlated with unfavorable prognosticators such as Breslow thickness, Clark level, mitotic activity, and the presence of ulceration. The expression of ENO1 also positively correlated with a greater thickness of the neoplastic infiltrate and a worse long-term prognosis for patients with cutaneous melanoma. We report significantly higher expression of ENO1 in melanoma cell lines in comparison to normal melanocytes. To conclude, our in vitro and clinical models showed that overexpression of ENO1 promotes invasiveness of melanoma cells and correlates with aggressive clinical behavior. These observations open the way to further search of a potential prognostic and therapeutic target in cutaneous melanoma.

M6A Methyltransferase METTL3 Promotes the Progression of Primary Acral Melanoma via Mediating TXNDC5 Methylation.

m6A modification is one of the most important post-transcriptional modifications in RNA and plays an important role in promoting translation or decay of RNAs. The role of m6A modifications has been highlighted by increasing evidence in various cancers, which, however, is rarely explored in acral melanoma. Here, we demonstrated that m6A level was highly elevated in acral melanoma tissues, along with the expression of METTL3, one of the most important m6A methyltransferase. Besides, higher expression of METTL3 messenger RNA (mRNA) correlated with a higher stage in primary acral melanoma patients. Knockdown of METTL3 decreased global m6A level in melanoma cells. Furthermore, METTL3 knockdown suppressed the proliferation, migration, and invasion of melanoma cells. In METTL3 knockdown xenograft mouse models, we observed decreased volumes and weights of melanoma tissues. Mechanistically, we found that METTL3 regulates certain m6A-methylated transcripts, thioredoxin domain containing protein 5 (TXNDC5), with the confirmation of RNA-seq, MeRIP-seq, and Western blot. These data suggest that METTL3 may play a key role in the progression of acral melanoma, and targeting the m6A dependent-METTL3 signaling pathway may serve as a promising therapeutic strategy for management of patients of acral melanomas.

TERT Promoter Revertant Mutation Inhibits Melanoma Growth through Intrinsic Apoptosis.

Simple SummaryTERT -146 C>T frequently occurs in many cancer cells. Research targeting the telomerase reverse transcriptase (TERT) promoter contributes to a better understanding of cancer development and treatment. Many conventional cancer treatments aim to develop new drugs targeting TERT. Here, for TERT -146 we converted T to C. The proliferation, migration and invasion of melanoma cells in vitro, and the growth of the tumor in vivo were inhibited. Moreover, the downregulated protein expression of B-cell lymphoma 2 (Blc-2) indicated that the TERT promoter revertant mutation abrogated the inhibitory effect of mutant TERT on apoptosis. These data elucidated the relationship between the TERT promoter revertant mutations and apoptosis for the first time, and also implied that TERT -146 may be a causal mutation of melanoma. This study provides a new insight into the TERT promoter revertant mutations and apoptosis. The TERT promoter provides preliminary validation of the potential tumor treatment.Human telomerase is a specialized DNA polymerase whose catalytic core includes both TERT and human telomerase RNA (hTR). Telomerase in humans, which is silent in most somatic cells, is activated to maintain the telomere length (TEL) in various types of cancer cells, including melanoma. In the vast majority of tumor cells, the TERT promoter is mutated to promote proliferation and inhibit apoptosis. Here, we exploited NG-ABEmax to revert TERT -146 T to -146 C in melanoma, and successfully obtained TERT promoter revertant mutant cells. These TERT revertant mutant cells exhibited significant growth inhibition both in vitro and in vivo. Moreover, A375−146C/C cells exhibited telomere shortening and the downregulation of TERT at both the transcription and protein levels, and migration and invasion were inhibited. In addition, TERT promoter revertant mutation abrogated the inhibitory effect of mutant TERT on apoptosis via B-cell lymphoma 2 (Blc-2), ultimately leading to cell death. Collectively, the results of our work demonstrate that reverting mutations in the TERT promoter is a potential therapeutic option for melanoma.

Long Non-Coding RNA CD27-AS1-208 Facilitates Melanoma Progression by Activating STAT3 Pathway.

Melanoma is the most lethal skin cancer that originates from epidermal melanocytes. Recently, long non-coding RNAs (lncRNAs) are emerging as critical regulators of cancer pathogenesis and potential therapeutic targets. However, the expression profile of lncRNAs and their role in melanoma progression have not been thoroughly investigated. Herein, we firstly obtained the expression profile of lncRNAs in primary melanomas using microarray analysis and unveiled the differentially-expressed lncRNAs compared with nevus. Subsequently, a series of bioinformatics analysis showed the great involvement of dysregulated lncRNAs in melanoma biology and immune response. Further, we identified lncRNA CD27-AS1-208 as a novel nuclear-localized factor with prominent facilitative role in melanoma cell proliferation, invasion and migration. Mechanistically, CD27-AS1-208 could directly interact with STAT3 and contribute to melanoma progression in a STAT3-dependent manner. Ultimately, the role of CD27-AS1-208 in melanoma progression in vivo was also investigated. Collectively, the present study offers us a new horizon to better understand the role of lncRNAs in melanoma pathogenesis and demonstrates that CD27-AS1-208 up-regulation contributes to melanoma progression by activating STAT3 pathway. Targeting CD27-AS1-208 in melanoma cells can be exploited as a potential therapeutic approach that needs forward validation in clinical trials in the future.

MiR-498 Targets UBE2T to Inhibit the Proliferation of Malignant Melanoma Cells.

Background: Malignant melanoma is a common malignant tumor and one of the tumors with the fastest growing incidence. The effect of microRNAs on the biological processing of malignant melanoma cells also have been reported. This study explores the ability of miR-498 to regulate the progression of malignant melanoma cells. Methods: The expression of miR-498 was detected by RT-qPCR. The proliferation, invasion, and migration of malignant melanoma cells were measured by cell counting kit-8, clone formation, and transwell assays. Flow cytometry assay detected the percentage of apoptotic cells. Western blot was used to detect the expression of markers related to epithelial-mesenchymal transition. The correction of miR-498 and UBE2T was explored by dual-luciferase assay and Western blot. Results: Overexpression of miR-498 inhibited the proliferation, invasion, migration, and induced cell apoptosis of M14 and A375 cells. In addition, the expression of epithelial-mesenchymal transition-related factors was altered by the overexpression of miR-498. miR-498 can directly target UBE2T 3'-UTR and inhibit UBE2T protein expression. The overexpression of UBE2T reversed the inhibitory effects of miR-498 on the progression of malignant melanoma cells. Furthermore, UBE2T mRNA was significantly highly expressed in malignant melanoma tissues. The high expression of UBE2T was associated with the poor overall survival rate of malignant melanoma patients. Conclusions: Altogether, our findings demonstrated that miR-498 significantly inhibited the proliferation, invasion, migration, and induced apoptosis of malignant melanoma cells and confirmed that miR-498 regulated malignant melanoma cell progression by targeting UBE2T.

Taraxasterol attenuates melanoma progression via inactivation of reactive oxygen species-mediated PI3K/Akt signaling pathway.

Background: Taraxasterol (TX), a pentacyclic triterpene, is one of the main active constituents isolated from Taraxacum officinale. A growing number of studies have reported that TX exhibits a wide range of biological activities such as anti-oxidative, anti-inflammatory, and neuro-protective effects. Recently, TX has been demonstrated to be a potential drug candidate for treatment of some types of cancers. However, the specific role of TX in melanoma remains unclear.Purpose: In this study, we aimed at exploration of the effect of TX on melanoma cell viability, apoptosis, migration, invasion, and epithelial-mesenchymal transition (EMT) as well as the underlying mechanisms.Research design: A375 and SK-MEL-28 cells were treated with various concentrations of TX for different times. Cell viability was measured using CCK-8 assay. Cell apoptosis was determined by flow cytometry. Transwell assays were performed to measure cell migration and invasion. The expression of E-cadherin, α-catenin, N-cadherin, vimentin, p-PI3K, PI3K, p-Akt and Akt was detected using western blot.Results: The study showed that TX induced A375 and SK-MEL-28 cell apoptosis. Furthermore, exposure to TX inhibited A375 and SK-MEL-28 cell migration and invasion. Besides, the EMT process was reversed in A375 and SK-MEL-28 cells after TX treatment. We also observed that TX reduced the protein expression of p-PI3K and p-Akt; thus, inhibiting activity of the PI3K/Akt pathway in A375 and SK-MEL-28 cells. In addition, TX treatment increased the levels of reactive oxygen species (ROS) in A375 and SK-MEL-28 cells, and treatment with the ROS scavenger NAC significantly rescued TX-induced down-regulation of p-PI3K and p-Akt in A375 and SK-MEL-28 cells.Conclusions: In conclusion, our study demonstrated that TX induced ROS accumulation followed by inactivation of the PI3K/Akt pathway and subsequently attenuated melanoma progression, suggesting that TX may be a potential candidate for treatment of melanoma.

Opposing Roles of Antimicrobial Peptides in Skin Cancers.

Antimicrobial peptides (AMPs), also known as host defense peptides, are ubiquitous naturally occurring molecules secreted by various cell types of the body. In the skin, AMPs serve as a first-line innate immune defense against exogenous microorganisms, and they orchestrate adaptive immune responses to exert several immunomodulatory functions. Emerging evidence indicates that AMPs not only contribute to certain inflammatory skin diseases but also play a role in skin tumor carcinogenesis. Available data support the hypothesis that AMPs possess both pro-tumor and anti-neoplastic properties. Although inconsistent observations reported by multiple studies make it challenging to summarize the precise roles of AMPs in cancer, the differential expression of AMPs in skin cancers, such as the increased expression of human beta-defensins in squamous cell carcinoma and the ability of cathelicidin LL-37 to induce malignant melanoma cell invasion, implies they have procancer activities. On the other hand, the observation that certain AMPs show cytotoxic activity against cancer cells of the colon and kidney suggests their inherent antitumor properties. In this review, we describe the roles and mechanisms of AMPs in skin cancer development. We believe that further research is needed to elucidate the impact of these AMPs in skin cancer biology and to explore their potential roles as diagnostic/prognostic biomarkers and as novel therapeutic targets.

MicroRNA-603 Promotes Progression of Cutaneous Melanoma by Regulating TBX5.

Background Although studies manifested that microRNA-603 plays a vital role in many cancers, the modulatory mechanism of microRNA-603 in cutaneous melanoma remains unknown. We aimed to investigate the roles of microRNA-603 in cutaneous melanoma cells. Methods First, microRNA-603 expression in cutaneous melanoma cell lines was detected by qRT-PCR. The mRNA and protein expression levels of TBX5 in cutaneous melanoma cell lines were tested by qRT-PCR and western blot, respectively. In addition, the interaction between microRNA-603 and TBX5 was determined by dual-luciferase reporter gene assay, and their impacts on the growth of cutaneous melanoma cells were detected by cellular function experiments such as MTT, colony formation, and Transwell assays. Results The expression level of microRNA-603 in human cutaneous melanoma cells was relatively upregulated. Overexpressing microRNA-603 could promote progression of cutaneous melanoma cells, while silencing microRNA-603 expression could suppress the malignant progression of cutaneous melanoma. In addition, TBX5 was lowly expressed in cutaneous melanoma cells. As confirmed by dual-luciferase assay, microRNA-603 could specifically bind to 3′UTR of TBX5 and regulate TBX5. The results of the rescue experiment demonstrated that inhibiting microRNA-603 expression could suppress the proliferation, migration, and invasion of cutaneous melanoma cells, but its suppressive effect could be restored by TBX5. Conclusion MicroRNA-603 could regulate the expression of TBX5, thus promoting the malignant progression of cutaneous melanoma cells.

ZC3H15 Correlates with a Poor Prognosis and Tumor Progression in Melanoma.

Zinc figure CCCH-type containing 15 (ZC3H15), also called developmentally regulated GTP-binding protein 1 (DRG1) family regulatory protein 1 (DFRP1), is a zinc finger containing protein. Despite playing a role in cellular signaling, it is found overexpressed in acute myeloid leukemia and also an independent prognostic marker in hepatocellular carcinoma patients. However, the biological effect of ZC3H15 in malignant melanoma (MM) remains unexplored. The expression of ZC3H15 in patients was analyzed using the R2: Genomics Analysis and Visualization Platform database. Immunohistochemical analysis, western blot, and qRT-PCR were used to detect ZC3H15 expression in melanoma tissues and cell lines. MTT, BrdU, flow cytometry assay, transwell, and western blot were performed to explore the proliferation, cell cycle, invasion, and migration of melanoma cells. We undertaken colony formation assay in vitro and tumor xenograft in vivo to detect the tumorigenicity of melanoma cells. In the present study, ZC3H15 was demonstrated highly expressed in melanoma tissues and cells. Elevated ZC3H15 impairs the survival of melanoma patients. Meanwhile, attenuation of ZC3H15 in melanoma cells inhibited cell proliferation and induced cycle arrest at G0/G1 phase. Consistently, the expression of cell cycle-related proteins cyclin dependent kinase 4 (CDK4), CDK6, and cyclin D1 (CCND1) was decreased while p21 was upregulated. Furthermore, we found the migration and invasion abilities were inhibited in ZC3H15-knockdown melanoma cells. In addition, downregulation of ZC3H15 resulted in inhibition of colony formation abilities in vitro and tumorigenesis in vivo. ZC3H15 promotes proliferation, migration/invasion, and tumorigenicity of melanoma cells. As a promising biomarker and therapeutic target in MM, ZC3H15 is worthy of further exploration.

Reciprocal Regulation of BRN2 and NOTCH1/2 Signaling Synergistically Drives Melanoma Cell Migration and Invasion

Phenotypic plasticity drives cancer progression, impacts treatment response, and is a major driver of therapeutic resistance. In melanoma, a regulatory axis between the MITF and BRN2 transcription factors has been reported to promote tumor heterogeneity by mediating switching between proliferative and invasive phenotypes, respectively. Despite strong evidence that subpopulations of cells that exhibit a BRN2high/MITFlow expression profile switch to a predominantly invasive phenotype, the mechanisms by which this switch is propagated and promotes invasion remain poorly defined. We have found that a reciprocal relationship between BRN2 and NOTCH1/2 signaling exists in melanoma cells invitro, within patient datasets, and in invivo primary and metastatic human tumors that bolsters acquisition of invasiveness. Working through the epigenetic modulator EZH2, the BRN2‒NOTCH1/2 axis is potentially a key mechanism by which the invasive phenotype is maintained. Given the emergence of agents targeting both EZH2 and NOTCH, understanding the mechanism through which BRN2 promotes heterogeneity may provide crucial biomarkers to predict treatment response to prevent metastasis.

High expression of lncRNA HSD11B1-AS1 indicates favorable prognosis and is associated with immune infiltration in cutaneous melanoma.

Cutaneous melanoma is an aggressive malignant cancer associated with poor prognosis. Identification of reliable biomarkers for predicting prognosis of melanoma contributes to improved clinical outcome and disease management. Long non-coding RNAs (lncRNAs) serve a crucial regulatory role of oncogenesis and tumor suppression in melanoma. Using data from The Cancer Genome Atlas database, novel lncRNA 11β-hydroxysteroid dehydrogenase type 1-antisense RNA 1 (HSD11B1-AS1) was identified, which was significantly downregulated in malignant melanoma and its downregulation was significantly associated with poor clinicopathological characteristics, including advanced T and pathological stage, Clark level, Breslow depth and ulceration and worse prognosis. Multivariate analysis showed that HSD11B1-AS1, as well as N stage and Breslow depth, were independent prognostic factors in cutaneous melanoma, and nomograms suggested a good predictive value of 1-, 3- and 5-year overall survival, progression-free interval and disease-specific survival. In vitro experiments verified the decreased HSD11B1-AS1 expression in melanoma cell lines compared with human epidermal melanocytes. Moreover, cell experiments in vitro, including Cell Counting Kit-8, colony formation, wound healing and Transwell assay, suggested that overexpression of HSD11B1-AS1 significantly inhibited melanoma cell proliferation, migration and invasion. Functional enrichment showed significantly enriched pathways in IFN-γ and -α response, TNF-α signaling via NF-κB and IL-2/STAT-5 and IL-6/JAK/STAT-3 signaling. In addition, immune infiltration analysis demonstrated that HSD11B1-AS1 may function by accelerating immune response regulation and the immune cell infiltration of various immunocytes, especially T, T helper 1, activated dendritic and B cells. The present study revealed HSD11B1-AS1 as a potential therapeutic target and promising biomarker for diagnosis and prognosis of cutaneous melanoma.

PARK7/DJ-1 inhibition decreases invasion and proliferation of uveal melanoma cells.

PARK7/DJ-1 is an oncogene that is associated with tumorigenesis in many cancers. Recent studies have demonstrated the importance of DJ-1 in the origin and development of uveal melanoma (UM). We present an analysis of the role of the DJ-1 protein in UM cells, especially in its effect on proliferation and migration. UM cells from a primary tumor, Mel 270, and its liver metastasis, OMM2.5, were transfected with lentiviral-delivered shRNA against PARK7/DJ-1. Evaluation of cell migration and proliferation was performed using the xCELLigence real-time cell analyzer (RTCA). The effect of DJ-1 inhibition on the PTEN-Akt signaling pathway was also studied by immunoblotting. The silencing of PARK7/DJ-1 oncoprotein expression produced a significant decrease of phosphorylated Akt (S473) in Mel270 and in metastatic OMM2.5 UM cells with no alteration on tumor suppressor PTEN expression. The diminution of PARK7/DJ-1 expression significantly inhibited real-time proliferation and invasion of Mel270 and OMM2.5 and the invasion potential of the metastatic cells. DJ-1 appears to play a key role on the PTEN/Akt pathway in UM. DJ-1 inhibition appears to have a negative effect on proliferation and invasion of UM cells. This suggests DJ-1 as a potential therapeutic target in UM.

An Orthotopic Model of Uveal Melanoma in Zebrafish Embryo: A Novel Platform for Drug Evaluation.

Uveal melanoma is a highly metastatic tumor, representing the most common primary intraocular malignancy in adults. Tumor cell xenografts in zebrafish embryos may provide the opportunity to study in vivo different aspects of the neoplastic disease and its response to therapy. Here, we established an orthotopic model of uveal melanoma in zebrafish by injecting highly metastatic murine B16-BL6 and B16-LS9 melanoma cells, human A375M melanoma cells, and human 92.1 uveal melanoma cells into the eye of zebrafish embryos in the proximity of the developing choroidal vasculature. Immunohistochemical and immunofluorescence analyses showed that melanoma cells proliferate during the first four days after injection and move towards the eye surface. Moreover, bioluminescence analysis of luciferase-expressing human 92.1 uveal melanoma cells allowed the quantitative assessment of the antitumor activity exerted by the canonical chemotherapeutic drugs paclitaxel, panobinostat, and everolimus after their injection into the grafted eye. Altogether, our data demonstrate that the zebrafish embryo eye is a permissive environment for the growth of invasive cutaneous and uveal melanoma cells. In addition, we have established a new luciferase-based in vivo orthotopic model that allows the quantification of human uveal melanoma cells engrafted in the zebrafish embryo eye, and which may represent a suitable tool for the screening of novel drug candidates for uveal melanoma therapy.

Silencing FYVE, RhoGEF, and PH domain containing 1 (FGD1) suppresses melanoma progression by inhibiting PI3K/AKT signaling pathway

ABSTRACT Cutaneous melanoma is the leading cause of death among skin cancers despite the availability of diverse treatments. FGD1 plays an important role in multiple cancers, but how it works in cutaneous melanoma has not been illustrated. Thus, this study was intended to investigate the roles of FGD1 and its underlying mechanisms in cutaneous melanoma. Bioinformatics tools and quantitative real-time polymerase chain reaction (qRT-PCR) were used to analyze the expression of FGD1 in cutaneous melanoma. After the knockdown of FGD1 in melanoma cells, the proliferation, migration, and invasion of cells were analyzed by cell counting kit-8 (CCK8) assay, colony formation assays and transwell assays. Western blot was used to check the expression of key factors in PI3K/AKT pathway. In addition, nude mice models were used to study the role of FGD1 in melanoma development and metastasis in vivo. The data demonstrated that FGD1 was up-regulated and predicted a poor clinical outcome for cutaneous melanoma patients. Knockdown of FGD1 inhibited melanoma cell proliferation, migration, and invasion. The expressions of p-PI3K and p-AKT were significantly decreased, while the expressions of PI3K and AKT showed no marked difference in the knockdown group. Meanwhile, knockdown of FGD1 suppressed the development of melanoma in vivo. This study suggested that knockdown of FGD1 could block melanoma formation and proliferation by inhibiting PI3K/AKT signaling pathway. FGD1 might be a promising therapeutic target for melanoma.

NUMB as a Therapeutic Target for Melanoma

The upregulation of the adaptor protein NUMB triggers melanocytic differentiation from multipotent skin stem cells, which share many properties with aggressive melanoma cells. Although NUMB acts as a tumor suppressor in various human cancer types, little is known about its role in melanoma. In this study, we investigated the role of NUMB in melanoma progression and its regulatory mechanism. Analysis of The Cancer Genome Atlas melanoma datasets revealed that high NUMB expression in melanoma tissues correlates with improved patient survival. Moreover, NUMB expression is downregulated in metastatic melanoma cells. NUMB knockdown significantly increased the invasion potential of melanoma cells in a three-dimensional collagen matrix invitro and in the lungs of a mouse model invivo; it also significantly upregulated the expression of the NOTCH target gene CCNE. Previous studies suggested that Wnt signaling increases NUMB expression. By mimicking Wnt stimulation through glycogen synthase kinase-3 inhibition, we increased NUMB expression in melanoma cells. Furthermore, a glycogen synthase kinase-3 inhibitor reduced the invasion of melanoma cells in a NUMB-dependent manner. Together, our results suggest that NUMB suppresses invasion and metastasis in melanoma, potentially through its regulation of the NOTCH‒CCNE axis and that the inhibitors that upregulate NUMB can exert therapeutic effects in melanoma.

Aloe-emodin inhibits the proliferation, migration, and invasion of melanoma cells via inactivation of the Wnt/beta-catenin signaling pathway

BackgroundAloe-emodin is reported as a potential cancer therapeutic agent due to its inhibition of the proliferation, migration, and invasion of cancer cells. This study aimed to confirm the effects of aloe-emodin on the progression of melanoma and identify the underlying molecular mechanisms.MethodsThe effects of aloe-emodin treatment (concentrations ranging from 0 to 25 µg, 48 h) on proliferation, apoptosis, distribution of cell cycle, migration, and invasion were detected by performing Cell Counting Kit-8 (CCK-8) assay, colony formation assay, flow cytometry, wound healing assay, and Transwell invasion experiments. Rescue experiments were carried out by overexpression of β-catenin to verify the role of β-catenin in the inhibition of melanoma by aloe-emodin. The analysis was carried out at the animal level by constructing tumor-bearing nude mice model.ResultsThe results showed that aloe-emodin prominently reduced the proliferation, migration, and invasion of melanoma cells. Additionally, it was found that aloe-emodin significantly enhanced the cell apoptosis and induced G2 phase arrest of melanoma cells via enhancing the expressions of cleaved-caspase3, bax, and reducing cyclinD1, c-myc, and bcl-2. In addition, aloe-emodin could also inhibit Wnt3a levels, and promote GSK3-beta and beta-catenin phosphorylation. In vivo experiments also showed that overexpression of beta-catenin reversed the effects of aloe-emodin on tumor growth.ConclusionsIn conclusion, our findings indicated that aloe-emodin might prominently inhibit the tumor growth and metastasis of melanoma via the Wnt/beta-catenin signaling pathway in vitro. Therefore, aloe-emodin may serve as a potential drug for the clinical treatment of melanoma.

IRF4-activated TEX41 promotes the malignant behaviors of melanoma cells by targeting miR-103a-3p/C1QB axis

BackgroundMalignant melanoma is an aggressive skin cancer and a tumor of melanocytic origin. Recent studies have suggested that long non-coding RNAs (lncRNAs) play crucial regulatory roles in multiple malignancies, including melanoma. Testis expressed 41 (TEX41) is a relatively new lncRNA whose mechanism in melanoma remains vague.AimsThis study aimed to explore the role and specific mechanism of TEX41 in melanoma.MethodsThe expression of genes involved in this study was determined by qRT-PCR. Functional assays were conducted to analyze the role of relevant genes in melanoma cells. The interaction between TEX41 promoter and IRF4 as well as the relationship among TEX41, miR-103a-3p and C1QB was verified by mechanism assays.ResultsIRF4 up-regulated TEX41 at the transcriptional level in melanoma cells. TEX41 knockdown hindered melanoma cell proliferation, migration and invasion while promoting cell apoptosis. TEX41 bound to miR-103a-3p and regulated C1QB. The suppressive impact of TEX41 depletion on melanoma cell malignant behaviors could be counteracted by miR-103a-3p inhibition or C1QB overexpression. Moreover, IRF4 could facilitate melanoma cell growth via up-regulating C1QB.ConclusionsIRF4-activated TEX41 sequestered miR-103a-3p and modulated C1QB to promote melanoma cell malignant behaviors, for which TEX41 might be regarded as a potential therapeutic target for melanoma.

ADT-OH inhibits malignant melanoma metastasis in mice via suppressing CSE/CBS and FAK/Paxillin signaling pathway.

Hydrogen sulfide (H2S) is widely recognized as the third endogenous gas signaling molecule and may play a key role in cancer biological processes. ADT-OH (5-(4-hydroxyphenyl)-3H-1,2-dithiocyclopentene-3-thione) is one of the most widely used organic donors for the slow release of H2S and considered to be a potential anticancer compound. In this study, we investigated the antimetastatic effects of ADT-OH in highly metastatic melanoma cells. A tail-vein-metastasis model was established by injecting B16F10 and A375 cells into the tail veins of mice, whereas a mouse footpad-injection model was established by injecting B16F10 cells into mouse footpads. We showed that administration of ADT-OH significantly inhibited the migration and invasion of melanoma cells in the three different animal models. We further showed that ADT-OH dose-dependently inhibited the migration and invasion of B16F10, B16F1 and A375 melanoma cells as evaluated by wound healing and Transwell assays in vitro. LC-MS/MS and bioinformatics analyses revealed that ADT-OH treatment inhibited the EMT process in B16F10 and A375 cells by reducing the expression of FAK and the downstream response protein Paxillin. Overexpression of FAK reversed the inhibitory effects of ADT-OH on melanoma cell migration. Moreover, after ADT-OH treatment, melanoma cells showed abnormal expression of the H2S-producing enzymes CSE/CBS and the AKT signaling pathways. In addition, ADT-OH significantly suppressed the proliferation of melanoma cells. Collectively, these results demonstrate that ADT-OH inhibits the EMT process in melanoma cells by suppressing the CSE/CBS and FAK signaling pathways, thereby exerting its antimetastatic activity. ADT-OH may be used as an antimetastatic agent in the future.