Poor Prognosis In Melanoma Patients Research Articles

Could the mitotic count improve personalized prognosis in melanoma patients?

A number of studies have indicated that the mitotic rate may be a predictive factor for poor prognosis in melanoma patients. The aim of this study was to investigate whether the mitotic rate is associated with other prognostic clinical and anatomopathological characteristics. After adjusting for other anatomopathological characteristics, we then verified the prognostic value of the number of mitoses, determining in which population subgroup this variable may have greater prognostic significance on 3-year mortality. The Veneto Cancer Registry (Registro Tumori del Veneto-RTV), a high-resolution population-based dataset covering the regional population of approximately 4.9 million residents, served as the clinical data source for the analysis. Inclusion criteria included all incident cases of invasive cutaneous malignant melanoma recorded in the RTV in 2015 (1,050 cases) and 2017 (1,205 cases) for which the number of mitoses was available. Mitotic classes were represented by Kaplan-Meier curves for short-term overall survival. Cox regression calculated hazard ratios in multivariable models to evaluate the independent prognostic role of different mitotic rate cut-offs. The results indicate that the mitotic rate is associated with other survival prognostic factors: the variables comprising the TNM stage (e.g., tumor thickness, ulceration, lymph node status and presence of metastasis) and the characteristics that are not included in the TNM stage (e.g., age, site of tumor, type of morphology, growth pattern and TIL). Moreover, this study demonstrated that, even after adjusting for these prognostic factors, mitoses per mm2 are associated with higher mortality, particularly in T2 patients. In conclusion, these findings revealed the need to include the mitotic rate in the histological diagnosis because it correlates with the prognosis as an independent factor. The mitotic rate can be used to develop a personalized medicine approach in the treatment and follow-up monitoring of melanoma patients.

FOXO3 Inhibits the Cisplatin Resistance and Progression of Melanoma Cells by Promoting CDKN1C Transcription.

Forkhead box O3 (FOXO3) and cyclin dependent kinase inhibitor 1C Gene (CDKN1C) have been shown to be involved in the melanoma process, but their roles in the cisplatin (DDP) resistance of melanoma remain unclear. The mRNA levels of CDKN1C and FOXO3 were measured using quantitative real-time PCR. The protein levels of CDKN1C, FOXO3 and mitochondrial oxidative phosphorylation (mtOXPHOS)-related markers were determinant by western blot analysis. The DDP resistance, proliferation, and apoptosis of melanoma cells were assessed by cell counting kit 8 assay, colony formation assay and flow cytometry. Glucose consumption, lactate production and ATP level were detected to assess glycolysis. The regulation of FOXO3 on CDKN1C was confirmed by ChIP assay and dual-luciferase reporter assay. In vivo experiments were performed to evaluate the effect of FOXO3 on DDP sensitivity in melanoma tumor tissues. CDKN1C and FOXO3 were downregulated in chemoresistant melanoma tissues, and their low expression levels were related to the poor prognosis of melanoma patients. Overexpression of CDKN1C and FOXO3 repressed DDP resistance, proliferation, and glycolysis, while promoted apoptosis and mtOXPHOS in DDP-resistant melanoma cells. Further analysis suggested that FOXO3 could bind to CDKN1C promoter region to enhance its transcription. Besides, CDKN1C knockdown reversed the regulation of FOXO3 on melanoma cell DDP resistance and progression. Moreover, FOXO3 overexpression enhanced the DDP sensitivity of melanoma tumor tissues in vivo. FOXO3 promoted the transcription of CDKN1C, thereby inhibiting the DDP resistance and progression of melanoma cells.

Alternative Wnt-signaling axis leads to a break of oncogene-induced senescence

Oncogene-induced senescence (OIS) is an important process that suppresses tumor development, but the molecular mechanisms of OIS are still under investigation. It is known that BRAFV600E-mutated melanocytes can overcome OIS and develop melanoma, but the underlying mechanism is largely unknown. Using an established OIS model of primary melanocytes transduced with BRAFV600E, YAP activity was shown to be induced in OIS as well as in melanoma cells compared to that in normal epidermal melanocytes. This led to the assumption that YAP activation itself is not a factor involved in the disruption of OIS. However, its role and interaction partners potentially change. As Wnt molecules are known to be important in melanoma progression, these molecules were the focus of subsequent studies. Interestingly, activation of Wnt signaling using AMBMP resulted in a disruption of OIS in BRAFV600E-transduced melanocytes. Furthermore, depletion of Wnt6, Wnt10b or β-catenin expression in melanoma cells resulted in the induction of senescence. Given that melanoma cells do not exhibit canonical Wnt/β-catenin activity, alternative β-catenin signaling pathways may disrupt OIS. Here, we discovered that β-catenin is an interaction partner of YAP on DNA in melanoma cells. Furthermore, the β-catenin–YAP interaction changed the gene expression pattern from senescence-stabilizing genes to tumor-supportive genes. This switch is caused by transcriptional coactivation via the LEF1/TEAD interaction. The target genes with binding sites for LEF1 and TEAD are involved in rRNA processing and are associated with poor prognosis in melanoma patients. This study revealed that an alternative YAP-Wnt signaling axis is an essential molecular mechanism leading to OIS disruption in melanocytes.

NETO2 promotes melanoma progression via activation of the Ca2+/CaMKII signaling pathway.

Melanoma is the most aggressive cutaneous tumor. Neuropilin and tolloid-like 2 (NETO2) is closely related to tumorigenesis. However, the functional significance of NETO2 in melanoma progression remains unclear. Herein, we found that NETO2 expression was augmented in melanoma clinical tissues and associated with poor prognosis in melanoma patients. Disrupting NETO2 expression markedly inhibited melanoma proliferation, malignant growth, migration, and invasion by downregulating the levels of calcium ions (Ca2+) and the expression of key genes involved in the calcium signaling pathway. By contrast, NETO2 overexpression had the opposite effects. Importantly, pharmacological inhibition of CaMKII/CREB activity with the CaMKII inhibitor KN93 suppressed NETO2-induced proliferation and melanoma metastasis. Overall, this study uncovered the crucial role of NETO2-mediated regulation in melanoma progression, indicating that targeting NETO2 may effectively improve melanoma treatment.

TRIM15 and CYLD regulate ERK activation via lysine-63-linked polyubiquitination.

The extracellular signal-regulated kinases ERK1 and ERK2 represent the foremost mitogenic pathway in mammalian cells, and their dysregulation drives tumorigenesis and confers therapeutic resistance. ERK1/2 are known to be activated by MAPK/ERK kinase (MEK)-mediated phosphorylation. Here we show that ERK1/2 are also modified by Lys63-linked polyubiquitin chains. We identify the tripartite motif-containing protein TRIM15 as a ubiquitin ligase, and the tumor suppressor CYLD as a deubiquitinase, for ERKs. TRIM15 and CYLD regulate ERK ubiquitination at defined lysine residues via mutually exclusive interactions as well as opposing activities. K63-linked polyubiquitination enhances ERK interaction with and activation by MEK. Down-regulation of TRIM15 inhibits growth of both drug-responsive and -resistant melanomas. Moreover, high TRIM15 expression and low CYLD expression are associated with poor prognosis of melanoma patients. These findings define a role of Lys63-linked polyubiquitination in the ERK signaling pathway and suggest a potential target for cancer therapy.

MiR-138-5p induces aggressive traits by targeting Trp53 expression in murine melanoma cells, and correlates with poor prognosis of melanoma patients

Deregulation of miRNAs contributes to the development of distinct cancer types, including melanoma, an aggressive form of skin cancer characterized by high metastatic potential and poor prognosis. The expression of a set of 580 miRNAs was investigated in a model of murine melanoma progression, comprising non-metastatic (4C11-) and metastatic melanoma (4C11+) cells. A significant increase in miR-138-5p expression was found in the metastatic 4C11+ melanoma cells compared to 4C11-, which prompted us to investigate its role in melanoma aggressiveness. Functional assays, including anoikis resistance, colony formation, collective migration, serum-deprived growth capacity, as well as in vivo tumor growth and experimental metastasis were performed in 4C11- cells stably overexpressing miR-138-5p. miR-138-5p induced an aggressive phenotype in mouse melanoma cell lines leading to increased proliferation, migration and cell viability under stress conditions. Moreover, by overexpressing miR-138-5p, low-growing and non-metastatic 4C11- cells became highly proliferative and metastatic in vivo, similar to the metastatic 4C11+ cells. Luciferase reporter analysis identified the tumor suppressor Trp53 as a direct target of miR-138-5p. Using data sets from independent melanoma cohorts, miR-138-5p and P53 expression were also found deregulated in human melanoma samples, with their levels negatively and positively correlated with prognosis, respectively. Our data shows that the overexpression of miR-138-5p contributes to melanoma metastasis through the direct suppression of Trp53.

Abstract 2762: Spatial distribution and immune cell infiltration at different sites of melanoma metastases (mets)

Abstract Purpose: The site of metastasis in advanced melanoma patients (pts) influences pt response to immunotherapy and overall prognosis. Liver mets are particularly resistant to immunotherapy and their presence often confers shorter survival and reduced response rates. This study characterised and compared the tumor immune microenvironment of melanoma mets at different anatomical sites. Methods: T-cell and myeloid cell markers were stained using multiplex IHC on FFPE samples from 136 untreated metastatic melanoma pts, from 5 anatomical sites (liver, lung, brain, subcutaneous, and lymph node (LN)). Cell densities, subpopulations and the spatial distribution of cells were compared between sites. Results: CD3+ T cell infiltration was less dense in the liver (med = 154.3 cells/mm2) and brain mets (med = 180.7 cells/mm2) v's lung (med = 434.7 cells/mm2) and LN mets (med = 504.8 cells/mm2) (p<0.05), and T-cells were further away from melanoma cells in liver v's lung mets (med distance = 83µm v's 57µm respectively; P<0.05). The liver displayed a unique T-cell profile, with a significantly lower proportion of CD3+ T cells expressing PD-1 (med = 0.7%) compared to all other sites (P<0.05) while brain mets expressed the highest proportion of PD-1+ T cells (med = 8.9%). There were higher proportions of Tim3+ T cells in liver (10.7%) and lung mets (12.9%) v's brain, subcut and LN mets (P<0.05). Specifically, in liver mets CD3+ T cells within 20um of a melanoma cell had a significantly higher expression of Tim3 (med = 18.57%) v's PD-1 (med = 2%). Brain mets had the lowest density of CD68+ macrophages (med = 33 cells/mm2) v's lung (med = 372 cells/mm2), liver (med = 290 cells/mm2) and Subcut mets (med = 154 cells/mm2). Lung mets also had the highest proportion of PD-L1+ macrophages (med = 18.73%) compared to liver (med = 5.2%) and brain mets (med = 0.65%). While the most highly expressed T cell population varied between sites, CD16+ macrophages were consistently the highest expressed macrophage subpopulation regardless of metastatic site. Conclusion: These data suggest that liver mets are less immunogenic, with fewer T cells and greater distances between CD3+ T cells and melanoma cells, and may account for the poor prognosis of melanoma patients with liver metastases and their reduced response rate to immunotherapy compared to other mets. While liver mets have reduced PD-1 expression, higher Tim3 expression in the liver may provide a therapeutic opportunity to improve outcomes for pts with liver mets by using anti-TIM3 immunotherapy. Overall, these data provide novel insights into the site-specific biology of melanoma mets, heterogeneity in the tumor immune microenvironment, and the need for site specific biomarkers to be considered when selecting treatment targets. Citation Format: Jordan W. Conway, Robert V. Rawson, James S. Wilmott, Georgina V. Long, Richard A. Scolyer, Inês Pires Da Silva. Spatial distribution and immune cell infiltration at different sites of melanoma metastases (mets) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2762.

Prognostic Value of Preoperative Inflammatory Markers in Melanoma Patients with Brain Metastases.

Background: Metastatic melanoma disease is accompanied by highly systemic inflammatory responses. The prognostic value of preoperative laboratory inflammation markers in brain metastatic melanoma patients has not been adequately investigated so far. Methods: Preoperative inflammatory blood parameters were correlated to overall survival (OS) rates in melanoma patients that underwent surgery for brain metastasis (BM) between 2013 and 2019 at the authors’ institution. Receiver operating characteristic (ROC) analyses were used for cutoff determination of routine laboratory parameters. Results: Median OS in the present cohort of 30 melanoma patients with surgically treated BM was 7 months (95% confidence interval (CI) 5.7–8.3). Initial elevated C-reactive protein (CRP) levels (>10 mg/L), neutrophil-to-lymphocyte ratio (NLR) ≥ 4, platelet-to-lymphocyte ratio (PLR) ≥ 145, and lymphocyte-to-monocyte ratio (LMR) < 2 were associated with significantly reduced OS rates. Conclusions: The present study identifies several preoperative peripheral inflammatory markers as indicators for poor prognosis in melanoma patients with BM undergoing neurosurgical treatment. Elevated initial CRP values, higher NLR and PLR, and lower LMR were associated with reduced OS and, thus, might be incorporated into preoperative interdisciplinary treatment planning and counseling for affected patients.

Circ-0079593 promotes proliferation and migration of melanoma cells by sponging microRNA-433 and elevating EGFR expression.

The aim of this study was to analyze the biological effects of circ-0079593 and its potential mechanism in the progression of melanoma. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was carried out to detect circ-0079593 expression in melanoma tissue samples and cell lines, and the relationship between circ-0079593 expression and prognosis of patients with melanoma was analyzed based on collected clinical information. Then, the melanoma cell line stably overexpressing circ-0079593 was constructed using lentiviral stable transfection technique, and then, Cell Counting Kit-8 (CCK-8) and transwell assays were carried out to detect the proliferation rate, migration, as well as invasion abilities of melanoma cells, respectively. In addition, the potential binding targets of circ-0079593 were searched through bioinformatics analysis, and the results were verified by Dual-Luciferase assay. It was found that, in comparison with the normal control group, circ-0079593 showed a significantly high expression in melanoma tissues and cell lines, which predicted a poor prognosis of melanoma patients. In vitro experiments showed that the overexpression of circ-0079593 remarkably enhanced proliferation rate, as well as invasion ability of melanoma cells. Moreover, bioinformatics data analysis revealed that there exist binding sites of microRNA-433 both in circ-0079593 and EGFR. Meanwhile, the results of the Luciferase assay confirmed that circ-0079593 probably bound to microRNA-433, as an endogenous competitive RNA (ceRNA), to regulate EGFR expression. At last, cell reverse experiments demonstrated that the overexpression of microRNA-433 could attenuate the capacity of melanoma cells to proliferate and migrate, while simultaneous overexpression of circ-0079593 partially restored those cell functions. In melanoma, circ-0079593 may serve as a cancer-promoting gene to accelerate the rates of cell proliferation and migration, which may exert its effects by elevating EGFR expression by binding to microRNA-433.

Prognostic score model-based signature genes for predicting the prognosis of metastatic skin cutaneous melanoma.

Cutaneous melanoma (SKCM) is the most invasive malignancy of skin cancer. Metastasis to distant lymph nodes or other system is an indicator of poor prognosis in melanoma patients. The aim of this study was to identify reliable prognostic biomarkers for SKCMs. Four RNA-sequencing datasets associated with SKCMs were downloaded from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) database as well as corresponding clinical information. Differentially expressed genes (DEGs) were screened between primary and metastatic samples by using MetaDE tool. Weighted gene co-expression network analysis (WGCNA) was conducted to screen functional modules. A prognostic score (PS)-based predictive model and nomogram model were constructed to identify signature genes and independent clinicopathologic factors. Based on MetaDE analysis and WGCNA, a total of 456 overlapped genes were identified as hub genes related to SKCMs progression. Functional enrichment analysis revealed these genes were mainly involved in the hippo signaling pathway, signaling pathways regulating pluripotency of stem cells, pathways in cancer. In addition, eight optimal DEGs (RFPL1S, CTSV, EGLN3, etc.) were identified as signature genes by using PS model. Cox regression analysis revealed that pathologic stage T, N and recurrence were independent prognostic factors. Three clinical factors and PS status were incorporated to construct a nomogram predictive model for estimating the three years and five-year survival probability of individuals. The prognosis prediction model of this study may provide a promising method for decision making in clinic and prognosis predicting of SKCM patients.

Expression of lncRNA FGD5-AS1 correlates with poor prognosis in melanoma patients.

Growing evidence demonstrates that long non-coding RNAs (lncRNAs) play an important role in cancer origination and progression. A novel identified lncRNA, FGD5 antisense RNA 1 (FGD5-AS1), was reported to be overexpressed in several tumors. The present study aimed to investigate the expression of FGD5-AS1 in melanoma and its associations with clinical prognosis in melanoma patients. The expression levels of FGD5-AS1 in 188 pairs of melanoma specimens and matched non-tumor specimens were determined using a real-time polymerase chain reaction. A chi-squared test was performed to determine the relationship between FGD5-AS1 levels and clinicopathological features. The overall survival rates of melanoma patients based on the expression of FGD5-AS1 were calculated by the Kaplan-Meier method with a log-rank test. Finally, univariate and multivariate assays were carried out to determine whether FGD5-AS1 was a prognostic factor in melanoma patients. We observed that FGD5-AS1 in melanoma specimens was distinctly up-regulated compared to adjacent non-tumor specimens (p < 0.01). In malignant cases, higher expression of FGD5-AS1 was prominently associated with tumor thickness (p = 0.024) and advanced tumor stage (p = 0.039). The data from our clinical study revealed that patients with high FGD5-AS1 expression had a distinctly shorter overall survival (p = 0.0034) and disease-free survival (p < 0.0001) than those with low FGD5-AS1 expression. Multivariate analysis demonstrated that high FGD5-AS1 expression may serve as a potential independent prognostic factor in melanoma. FGD5-AS1 may act as a prognostic predictor and a possible drug-target for melanoma patients.

Down-regulated HDAC3 elevates microRNA-495-3p to restrain epithelial-mesenchymal transition and oncogenicity of melanoma cells via reducing TRAF5.

MicroRNAs (miRNAs) are emerging biomarkers in biological processes and the role of miR‐495‐3p has been identified in melanoma, while the detailed molecular mechanisms remain to be further explored. We aim to explore the effect of histone deacetylase 3 (HDAC3) and miR‐495‐3p on epithelial‐mesenchymal transition (EMT) and oncogenicity of melanoma cells by regulating tumour necrosis factor receptor‐associated factor 5 (TRAF5). Levels of HDAC3, miR‐495‐3p and TRAF5 in melanoma tissues and pigmented nevus tissues were determined, and the predictive roles of HDAC3 and miR‐495‐3p in prognosis of melanoma patients were measured. The melanoma cells were screened and transfected with relative oligonucleotides and plasmids, and the expression of HDAC3, miR‐495‐3p and TRAF5, and phenotypes of melanoma cells were gauged by a series of assays. The relations between HDAC3 and miR‐495‐3p, and between miR‐495‐3p and TRAF5 were confirmed. HDAC3 and TRAF5 were increased while miR‐495‐3p was decreased in melanoma cells and tissues, and the low expression of miR‐495‐3p as well as high expression of HDAC3 indicated a poor prognosis of melanoma patients. Inhibited HDAC3 elevated miR‐495‐3p to suppress EMT and oncogenicity of melanoma cells by reducing TRAF5. HDAC3 particularly bound to miR‐495‐3p and TRAF5 was the target gene of miR‐495‐3p. Our results revealed that down‐regulated HDAC3 elevates miR‐495‐3p to suppress malignant phenotypes of melanoma cells by inhibiting TRAF5, thereby repressing EMT progression of melanoma cells. This study may provide novel targets for melanoma treatment.

Concomitant Nuclear Localization of BRAFV600E and HO-1 Is Associated with Drug Resistance and Poor Prognosis in Melanoma Patients

Concomitant Nuclear Localization of BRAFV600E and HO-1 Is Associated with Drug Resistance and Poor Prognosis in Melanoma Patients

Abstract B09: Nitric oxide stimulates PI3K-AKT pathway activation by S-nitrosylation of PTEN in human melanoma cells

Abstract Based on our previous finding that inflammation associated nitric oxide synthase (NOS) expression in melanoma and its association with poor prognosis in melanoma patients, we investigated the role of nitric oxide (NO) on the PI3K-Akt pathway. Human melanoma cell lines were exposed in vitro to the NO donor (DETA NONOate), and increased Akt Serine 473 phosphorylation (pAkt S473) was detected after addition of 50-500μM DETA NONOate at as early as 2 hours. Significant increases of pAkt S473 were observed mostly in cell lines with wild-type PTEN, such as A375 and MeWo, which under our conditions do not have elevated basal Akt phosphorylation. A375 cells were further examined for DETA NONOate-induced functional consequences of Akt phosphorylation and activation; enhanced kinase activity was found to increase phosphorylation of 12 of 16 AKT signaling proteins, which include GSK, MAPK, Bad, and others. By analyzing melanoma data in The Cancer Genome Atlas (TCGA), we found a similar result that patients with positive iNOS mRNA expression have higher pAkt S473 levels compared with those without iNOS. When both PTEN and iNOS expression status were analyzed, pAkt S473 is only significantly (P&amp;lt;0.05) increased in patients with positive iNOS and intact PTEN, supporting our hypothesis that NO may inhibit the role of PTEN as the PI3K antagonist. Further examination in A375 cells expressing iNOS confirmed the endogenous formation of PTEN S-nitrosylation (SNO), a NO-dependent post-translational modification. PTEN in cells treated with NO showed attenuated phosphatase activity. Consistent with this view, an analysis from stage III melanoma patient tissue microarray also revealed that patients with PTEN expression had a lower survival rate when they also had positive iNOS expression. In summary, our study revealed NO can stimulate the PI3K-Akt pathway in human melanoma cells, which could be promoted by NO-mediated PTEN SNO. These experimental discoveries are supported by clinical association data and have provided one plausible mechanistic insight into the possible functional consequences of inflammatory NO produced in human melanoma cells and microenvironment. Citation Format: Zhen Ding, Dai Ogata, Jason Roszik, Yong Qin, Sun-Hee Kim, Suhendan Ekmekcioglu, Elizabeth A. Grimm. Nitric oxide stimulates PI3K-AKT pathway activation by S-nitrosylation of PTEN in human melanoma cells [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr B09.

DDX39 Overexpression Predicts a Poor Prognosis and Promotes Aggressiveness of Melanoma by Cooperating With SNAIL.

This study aimed to investigate the prognostic value and molecular mechanism of DDX39 and its effector SNAIL in melanoma. First, overexpression of DDX39 in melanoma, which was identified by database analysis, was further validated in patient tissues. Cell growth, cell cycle, cell migration, and cell invasion assays were then performed to evaluate the effects of downregulated DDX39 on the melanoma cell proliferation and aggressiveness. The same approaches were also used to reveal the cooperation of the transcription factor SNAIL with DDX39 to promote the aggressiveness of melanoma cells. We found that the expression of DDX39 was significantly upregulated in melanoma tissue compared to pigmented nevus tissue, and it was positively correlated with the clinical stage defined by the American Joint Committee on Cancer (AJCC) and the prognosis. Downregulation of DDX39 in melanoma cells was found to significantly inhibit cell proliferation, increase G2/M cell cycle arrest, enhance caspase-mediated cell apoptosis, and suppress cell invasion and migration. In addition, we demonstrated that the overexpression of SNAIL could restore the cell growth and aggressiveness impaired by DDX39 RNA interference. Immunohistochemical staining also showed a positive correlation between DDX39 overexpression and SNAIL overexpression in melanoma tissues, suggesting that SNAIL is one of the effectors activated by DDX39. In summary, the overexpression of DDX39 and SNAIL was positively related to the poor prognosis of melanoma patients and the increased aggressiveness of melanoma cells. Our study provides valuable evidence regarding the prognostic value of DDX39 and SNAIL as well as their potential as novel therapeutic targets for treating melanoma patients.

Abrogation of RAB27A expression transiently affects melanoma cell proliferation.

The role of the small GTPase RAB27A as an essential melanosome trafficking regulator in melanocytes is well-accepted. A decade ago, RAB27A was identified as a tumor dependency gene that promotes melanoma cell proliferation. RAB27A has since been linked to another propeller of cancer progression: exosome secretion. We have recently demonstrated that RAB27A is overexpressed in a subset of melanomas. High RAB27A gene and protein expression correlate with poor prognosis in melanoma patients. Mechanistic investigations revealed that the generation of pro-invasive exosomes was RAB27A-dependent and, therefore, silencing RAB27A reduced melanoma cell invasion in vitro and in vivo. However, previous studies have implicated RAB27A to be involved in both proliferation and invasion of melanoma cells. Employing four human cell lines, stratified by RAB27A expression, and one RAB27A-high mouse cell line, we demonstrate in this study that the effects of abrogating RAB27A expression on proliferation are only temporary, in contrast to our previously reported persistent effects on tumor invasion and metastasis. Therefore, we assist in the dissection of the short-term effects of RAB27A knockdown on melanoma cell proliferation versus long-term effects on melanoma invasion and metastasis. We believe that our findings provide novel insights into the effects of RAB27A blockade.

Circular RNA circ_0020710 drives tumor progression and immune evasion by regulating the miR-370-3p/CXCL12 axis in melanoma

BackgroundCircular RNAs (circRNAs) have been reported to have critical regulatory roles in tumor biology. However, their contribution to melanoma remains largely unknown.MethodsCircRNAs derived from oncogene CD151 were detected and verified by analyzing a large number of melanoma samples through quantitative real-time polymerase chain reaction (qRT-PCR). Melanoma cells were stably transfected with lentiviruses using circ_0020710 interference or overexpression plasmid, and then CCK-8, colony formation, wound healing, transwell invasion assays, and mouse xenograft models were employed to assess the potential role of circ_0020710. RNA immunoprecipitation, luciferase reporter assay and fluorescence in situ hybridization were used to evaluate the underlying mechanism of circ_0020710.ResultsOur findings indicated that circ_0020710 was generally overexpressed in melanoma tissues, and high level of circ_0020710 was positively correlated with malignant phenotype and poor prognosis of melanoma patients. Elevated circ_0020710 promoted melanoma cell proliferation, migration and invasion in vitro as well as tumor growth in vivo. Mechanistically, we found that high level of circ_0020710 could upregulate the CXCL12 expression via sponging miR-370-3p. CXCL12 downregulation could reverse the malignant behavior of melanoma cells conferred by circ_0020710 over expression. Moreover, we also found that elevated circ_0020710 was correlated with cytotoxic lymphocyte exhaustion, and a combination of AMD3100 (the CXCL12/CXCR4 axis inhibitor) and anti-PD-1 significantly attenuated tumor growth.ConclusionsElevated circ_0020710 drives tumor progression via the miR-370-3p/CXCL12 axis, and circ_0020710 is a potential target for melanoma treatment.

SNHG16 promotes cell proliferation and migration through sponging miR-132 in melanoma.

Melanoma, which originates from the transformation of normal melanocytes, is one of the three main types of skin cancer. We aimed to explore the functions of SNHG16 and miR-132 in melanoma. CCK-8, Transwell assays were used to measure the viability and migration, respectively. Spearman's correlation analysis was performed to analyze the relationship between the expression of SNHG16, miR-132 and LAPTM4B in melanoma tissues. SNHG16 was overexpressed, and miR-132 was low expressed in melanoma tissues and cell lines. Moreover, overexpression of SNHG16 was associated with poor prognosis of melanoma patients. The expression of SNHG16 had a negative connection with the expression of miR-132, and it had a positive relationship with the expression of LAPTM4B in melanoma tissues. Knockdown of SNHG16 or overexpression of miR-132 inhibited SK-MEL-2 cell proliferation and migration. In addition, we confirmed that SNHG16 directly binding to miR-132 promotes the expression of LAPTM4B, facilitating the tumorigenesis of melanoma. SNHG16 promotes the expression of LAPTM4B by sponging miR-132, thereby acting as an oncogene in melanoma. This study demonstrated that the lncRNA-miRNA-mRNA signal cascade existed in melanoma, which may help elucidate the tumorigenesis and development mechanism of melanoma.

Hsa-let-7b Suppresses Cell Proliferation by Targeting UHRF1 in Melanoma

UHRF1 promotes melanoma progression by inducing cell proliferation, and is correlated with poor prognosis of melanoma patients. However, the regulation mechanism has not been fully elaborated. Here, we detected hsa-let-7b expression and its role in melanoma. Through Targetscan and miRanda predication, 30 overlapped miRNAs were found; further survival analysis revealed that hsa-let-7b was the only miRNA that affected the overall survival. Overexpressed hsa-let-7b could significantly inhibit the proliferation ability of A375 and A2058 cells, and this phenomenon was reversed after co-transfection with pLenti-UHRF1. In conclusion, hsa-let-7b regulates melanoma cells proliferation in vitro by targeting UHRF1.

Progranulin promotes melanoma progression by inhibiting natural killer cell recruitment to the tumor microenvironment.

Progranulin (PGRN) is a growth factor with significant biological effects in different types of cancer. However, its role in melanoma progression has not been explored. In this study, we first analyze clinical datasets and show that high PGRN expression levels are correlated with poor prognosis of melanoma patients. Further, we demonstrate in a transplanted murine melanoma model in which the endogenous Grn gene encoding PGRN has been deleted that tumor-derived, not host-derived PGRN, promotes melanoma growth and metastasis. Immunological analyses reveal an enhanced infiltration of natural killer cells, but not T lymphocytes, into PGRN-deficient tumors compared to the wild type control. Antibody-mediated depletion confirms the critical role of NK cells in controlling B16 tumor growth. RNA-seq analysis reveals that several chemokines including CCL5 are strongly upregulated in PGRN-deficient tumor. Silencing CCL5 expression in PGRN-deficient tumor reduces NK cell recruitment and restores tumor growth to the control level. Lastly, we show that PGRN inhibits Ccl5 gene expression at the transcriptional level. This study highlights a novel and critical role of PGRN in melanoma growth and metastasis and suggests that it may represent a potential therapeutic target.