Expression In Melanoma Cells Research Articles

Reprogramming of T cell-derived small extracellular vesicles using IL2 surface engineering induces potent anti-cancer effects through miRNA delivery.

T cell-derived small extracellular vesicles (sEVs) exhibit anti-cancer effects. However, their anti-cancer potential should be reinforced to enhance clinical applicability. Herein, we generated interleukin-2-tethered sEVs (IL2-sEVs) from engineered Jurkat T cells expressing IL2 at the plasma membrane via a flexible linker to induce an autocrine effect. IL2-sEVs increased the anti-cancer ability of CD8+ T cells without affecting regulatory T (Treg ) cells and down-regulated cellular and exosomal PD-L1 expression in melanoma cells, causing their increased sensitivity to CD8+ T cell-mediated cytotoxicity. Its effect on CD8+ T and melanoma cells was mediated by several IL2-sEV-resident microRNAs (miRNAs), whose expressions were upregulated by the autocrine effects of IL2. Among the miRNAs, miR-181a-3p and miR-223-3p notably reduced the PD-L1 protein levels in melanoma cells. Interestingly, miR-181a-3p increased the activity of CD8+ T cells while suppressing Treg cell activity. IL2-sEVs inhibited tumour progression in melanoma-bearing immunocompetent mice, but not in immunodeficient mice. The combination of IL2-sEVs and existing anti-cancer drugs significantly improved anti-cancer efficacy by decreasing PD-L1 expression in vivo. Thus, IL2-sEVs are potential cancer immunotherapeutic agents that regulate both immune and cancer cells by reprogramming miRNA levels.

Interference in melanoma CD248 function reduces vascular mimicry and metastasis

BackgroundTumor vascular mimicry is an emerging issue that affects patient survival while having no treatment at the current moment. Despite several factors implicated in vascular mimicry, little is known about stromal factors that modulate tumor microenvironment and shape malignant transformation. CD248, a type-I transmembrane protein dominantly expressed in stromal cells, mediates the interaction between cells and extracellular matrix proteins. CD248 protein expression is associated with the metastatic melanoma phenotype and promotes tumor progression in the stromal cells. This study aimed to explore the cell-autonomous effects of CD248 in melanoma vascular mimicry to aid cancer therapy development.MethodsLoss-of-function approaches in B16F10 melanoma cells were used to study the cell-autonomous effects of CD248 on cell adhesion, migration, proliferation, and vascular mimicry. A solid-phase binding assay was performed to identify the interaction between CD248 and fibronectin. Horizontal and vertical cell migration assays were performed to analyze cell migration activity, and cell-patterned network formation on Matrigel was used to evaluate vascular mimicry activity. Recombinant CD248 (rCD248) proteins were generated, and whether rCD248 interfered with melanoma CD248 functions was evaluated in vitro. An experimental lung metastasis mouse model was used to investigate the effect of rCD248 treatment in vivo.ResultsCD248 protein expression in melanoma cells was increased by a fibroblast-conditioned medium. Knockdown of CD248 expression significantly decreased cell adhesion to fibronectin, cell migration, and vascular mimicry in melanoma cells. The lectin domain of CD248 was directly involved in the interaction between CD248 and fibronectin. Furthermore, rCD248 proteins containing its lectin domain inhibited cell adhesion to fibronectin and slowed down cell migration and vascular mimicry. Treatment with rCD248 protein could reduce pulmonary tumor burden, accompanied by a reduction in vascular mimicry in mice with melanoma lung metastasis.ConclusionCD248 expression in melanoma cells promotes malignant transformation by increasing the activity of cell adhesion, migration, and vascular mimicry, whereas rCD248 protein functions as a molecular decoy interfering with tumor-promoting effects of CD248 in melanoma cells.

Centrosomal protein55 enhances melanoma cell proliferation, invasion and migration through PI3K/AKT signaling

Purpose: To investigate the role of centrosomal protein55 (CEP55) in melanoma. 
 Methods: The CEP55 expression in human melanoma cells and normal human melanocytes were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot. Cell proliferation was evaluated by colony formation and CCK8 assays, while cell cycle was assessed by flow cytometry. Transwell assay was used to investigate cell migration and invasion. 
 Results: The CEP55 protein expression was higher in A-2058 and A375 melanoma cells than in normal HEMn-LP cells. Overexpression of CEP55 increased melanoma cell viability and the number of melanoma cell colonies (p < 0.01), while CEP55 silencing reduced melanoma cell viability and proliferation. Overexpression of CEP55 promoted cell cycle (p < 0.01) via decreased p21 expression, but increased CyclinD1 and CDK1 expression. Knockdown of CEP55 enhanced p21 expression and reduced CyclinD1 and CDK1 expression to induce cell cycle arrest. Knockdown of CEP55 suppressed melanoma cell migration and invasion by downregulating p-AKT and p-PI3K. 
 Conclusion: Centrosomal protein55 functions as an oncogene in melanoma by activating PI3K/AKT signaling. Therefore, CEP55 might be a promising target for melanoma diagnosis and treatment.

Netrin-1 Stimulates Migration of Neogenin Expressing Aggressive Melanoma Cells.

Netrin-1 is a neural guidance factor that regulates migration and positioning of neural crest-derived cells during embryonic development. Depending on the type of Netrin-1 receptor expression, cells are either attracted or repulsed by Netrin-1. Postnatal expression of Netrin-1 is detected in brain, colon, liver, and kidney, which are common sites of cancer metastasis, including melanoma. Thus, understanding the dynamics between Netrin-1 and its receptors could explain the attraction of melanoma towards these Netrin-1-expressing tissues. Here, we investigate whether the Netrin-1-attractive receptor Neogenin can affect migration of melanoma cells towards a Netrin-1 source. Results from Western blot (WB) analysis show higher expression of Neogenin in aggressive compared to non-aggressive melanoma cells. Cell migration experiments show increased migration of Neogenin-expressing aggressive melanoma cells towards exogenous, soluble recombinant human Netrin-1 and towards a Netrin-1-expressing cell line. Furthermore, WB reveals ERK1/2 activation and increased N-cadherin expression in Neogenin-expressing aggressive melanoma cells treated with rhNetrin-1. Moreover, treatment with anti-Neogenin blocking antibody caused decreased migration towards Netrin-1-expressing cells and reduced ERK1/2 activity in Neogenin-expressing aggressive melanoma cells. These results suggest Neogenin may play a role during migration of melanoma cells towards Netrin-1 via ERK1/2 signaling.

Bidirectional regulation between tumor cell-intrinsic PD-L1 and TGF-β1 in epithelial-to-mesenchymal transition in melanoma.

Transforming growth factor-β1 (TGF-β1) is the predominant form of TGF-β and induces epithelial-to-mesenchymal transition (EMT) in melanoma. Tumor cell-intrinsic programmed death ligand-1 (PD-L1) plays a crucial role in maintenance of the EMT in melanoma. However, the relationship among tumor cell-intrinsic PD-L1, TGF-β1 and EMT is very complicated. We investigated the bidirectional regulation between cell-intrinsic PD-L1 and TGF-β1 in melanoma, and explored the role of PD-L1 in TGF-β1-induced EMT and tumor progression. We found that TGF-β1 upregulated PD-L1 expression in B16-F0 and B16-F10 melanoma cells. Interestingly, PD-L1 also enhanced the intracellular TGF-β1 mRNA levels and induced the secretion of TGF-β1. Immunohistochemical staining revealed that PD-L1 protein expression was co-localized with α-smooth muscle actin (SMA) protein expression in melanoma, suggesting that PD-L1 was associated with EMT. By using shRNA lentivirus to knockdown PD-L1 (PD-L1-shRNA) in melanoma cell lines, we showed that TGF-β1-induced EMT was significantly inhibited in PD-L1-shRNA melanoma cells, which was characterized by the lower fibronectin (FN1) mRNA and higher E-cadherin (CDH1) mRNA levels (both are EMT markers) than that in control. TGF-β1-induced melanoma cell proliferation and migration were also markedly inhibited in PD-L1-shRNA cells. Consistent with the observation in vitro, PD-L1 knockdown inhibited tumor growth and repressed TGF-β1-induced EMT characterized by reduction of FN1 and increase of CDH1 in mouse model. The present study demonstrated a bidirectional regulation between cell-intrinsic PD-L1 and TGF-β1 in melanoma, which may help in designing promising combinations which include targeting TGF-β1 signaling along with PD-L1.

Impaired expression of serine/arginine protein kinase 2 (SRPK2) affects melanoma progression.

Melanoma is one of the most aggressive tumors, and its lethality is associated with the ability of malignant cells to migrate and invade surrounding tissues to colonize distant organs and to generate widespread metastasis. The serine/arginine protein kinases 1 and 2 (SRPK1 and SRPK2) are classically related to the control of pre-mRNA splicing through SR protein phosphorylation and have been found overexpressed in many types of cancer, including melanoma. Previously, we have demonstrated that the pharmacological inhibition of SRPKs impairs pulmonary colonization of metastatic melanoma in mice. As the used compounds could target at least both SRPK1 and SRPK2, here we sought to obtain additional clues regarding the involvement of these paralogs in melanoma progression. We analyzed single-cell RNA sequencing data of melanoma patient cohorts and found that SRPK2 expression in melanoma cells is associated with poor prognosis. Consistently, CRISPR-Cas9 genome targeting of SRPK2, but not SRPK1, impaired actin polymerization dynamics as well as the proliferative and invasive capacity of B16F10 cells in vitro. In further in vivo experiments, genetic targeting of SRPK2, but not SRPK1, reduced tumor progression in both subcutaneous and caudal vein melanoma induction models. Taken together, these findings suggest different functional roles for SRPK1/2 in metastatic melanoma and highlight the relevance of pursuing selective pharmacological inhibitors of SRPK2.

MCP-1/CCR2 axis inhibition sensitizes the brain microenvironment against melanoma brain metastasis progression.

Development of resistance to chemo- and immunotherapies often occurs following treatment of melanoma brain metastasis (MBM). The brain microenvironment (BME), particularly astrocytes, cooperate toward MBM progression by upregulating secreted factors, among which we found that monocyte chemoattractant protein-1 (MCP-1) and its receptors, CCR2 and CCR4, were overexpressed in MBM compared with primary lesions. Among other sources of MCP-1 in the brain, we show that melanoma cells altered astrocyte secretome and evoked MCP-1 expression and secretion, which in turn induced CCR2 expression in melanoma cells, enhancing in vitro tumorigenic properties, such as proliferation, migration, and invasion of melanoma cells. In vivo pharmacological blockade of MCP-1 or molecular knockout of CCR2/CCR4 increased the infiltration of cytotoxic CD8+ T cells and attenuated the immunosuppressive phenotype of the BME as shown by decreased infiltration of Tregs and tumor-associated macrophages/microglia in several models of intracranially injected MBM. These in vivo strategies led to decreased MBM outgrowth and prolonged the overall survival of the mice. Our findings highlight the therapeutic potential of inhibiting interactions between BME and melanoma cells for the treatment of this disease.

The Inhibitory Effect of Polyphenon 60 from Green Tea on Melanin and Tyrosinase in Zebrafish and A375 Human Melanoma Cells.

Polyphenon 60 (PP60) from green tea has long been used as an antioxidant, anticancer, antimicrobial, and antimutagenic. Aim of the Study. To investigate tyrosinase inhibition-related kinetic mechanism and antimelanogenesis potential of PP60. Materials and Methods. The effect of PP60 on melanin and tyrosinase was evaluated in A375 melanoma cells and zebrafish embryos. The melanoma cells were treated with 20, 40, and 60 µg/mL of PP60, and tyrosinase expression was induced by using L-DOPA. The western blot method was used for the evaluation of tyrosinase expression. Cell lysates were prepared from treated and untreated cells for cellular tyrosinase and melanin quantification. Furthermore, zebrafish embryos were treated with 20, 40, and 60 µg/mL of PP60 and reference drug kojic acid for determination of depigmentation and melanin quantification. In vitro assays were also performed to examine the impact of PP60 on mushroom tyrosinase activity. To determine cytotoxicity, MTT was used against melanoma cell line A375. Results. PP60 showed good tyrosinase inhibitory activity with an IC50 value of 0.697 ± 0.021 µg/mL as compared to kojic acid a reference drug with an IC50 value of 2.486 ± 0.085 µg/mL. Kinetic analysis revealed its mixed type of inhibition against mushroom tyrosinase. In addition, western blot analysis showed that at 60 µg/mL dose of PP60 significantly reduced L-DOPA-induced tyrosinase expression in melanoma cells. PP60 significantly inhibits the cellular tyrosinase (p < 0.05) and reduces the melanin (p < 0.05) contents of melanoma cells. Furthermore, PP60 was found to be very potent in significantly reducing the zebrafish embryos' pigmentation (p < 0.05) and melanin (p < 0.05) content at the dose of 60 µg/mL. Conclusions. Our results demonstrate that PP60 has a strong potency to reduce pigmentation. It may be useful for the cosmetic industries to develop skin whitening agents with minimal toxic effects.

Upregulation LncRNA MEG3 expression suppresses proliferation and metastasis in melanoma via miR-208/SOX4.

Long non-coding RNAs (lncRNAs) regulate gene expression and play a significant role in cancer progression. Previously, downregulation of lncRNA MEG3 was shown to associate with poor clinical outcomes in melanoma patients. The basis for this association has not been described and the aims of this study were to identify a role for lncRNA MEG3 in melanoma and to describe its regulatory mechanism of action. RT-qPCR was used to detect lncRNA MEG3 expression in melanoma cells and tissues. Luciferase reporter assays were used to identify lncRNA MEG3 downstream targets. Melanoma cells were transfected with various expression vectors and these transfected cells were assessed for; migration, colony formation, proliferation, in vivo tumorigenesis, and metastatic potential. Melanoma cell lines were found to be sensitive to lncRNA MEG3 expression levels and overexpression was found to inhibit melanoma cell proliferation and invasion, both in vitro and in vivo. Luciferase reporter assays identified miR-208 and SOX4 as downstream targets of lncRNA MEG3. Overexpression of miR-208 and silencing of SOX4 rescued invasion and proliferation by cells that overexpressed lncRNA MEG3. Moreover, lncRNA MEG3 inhibited cancer stem cell differentiation and suppressed melanoma progression and metastasis through inhibition of miR-208 by SOX4.

Microphthalmia Transcription Factor almost Thirty Years after: Its Role in Melanogenesis and its Plant-Derived Inhibitors

It has been almost thirty years since the first publication on microphthalmia-associated transcription factor (MITF) in 1993. MITF, which plays an important role in the melanogenesis process, is an interesting target for melanoma therapy, due to its associates with melanoma survival. MITF promotes melanoma cell proliferation, whereas the sustained suppression of MITF expression causes aging. MITF contributes to differentiation, which involves breaking out of the cell cycle and triggering a melanogenesis, and this function appears to often persist during melanoma development given the frequently observed high pigmented lesions, even in the late stages of melanoma. Several drugs that could inhibit MITF e.g. histone deacetylase inhibitors, such as sodium butyrate and trichostatin A, have been proven could suppress M-MITF expression in melanoma cells. H1-receptor antagonists, particularly loratadine, could downregulate MITF and tyrosinase in melanocytes. Some plants can inhibit MITF e.g Gentiana veitchiorum Hemsl., Thymelaea hirsuta, Argania spinosa L. In this review, we update the information about MITF and describe the mechanism of its inhibitors in preventing melanogenesis.

Abstract LB098: Integrative approaches to modulate antigen presentation and boost cancer immune response

Abstract Immune checkpoint blockade (ICB) therapy revolutionized cancer treatment, but patients with impaired MHC-I and/or MHC-II expression show inferior response. We observed differential expression patterns for MHC-I and MHC-II in cancer cells and applied multiple approaches to examine their regulatory mechanisms. To identify the modulators of MHC-I, we combined FACS-based genome-wide CRISPR screens with data-mining from public data. We identified TRAF3, a suppressor of the NFkB pathway, as a negative regulator of MHC-I. The Traf3-knockout gene expression signature is associated with better survival in ICB-naïve patients with cancer and better ICB response. We then screened for drugs with similar transcriptional effects as this signature and identified Second Mitochondria-derived Activator of Caspase (SMAC) mimetics. We experimentally validated that the SMAC mimetic birinapant upregulates MHC-I, sensitizes cancer cells to T cell-dependent killing, and adds to ICB efficacy. In contrast to MHC-I, the expression of MHC-II shows dramatic intra- and inter-sample heterogeneity. To identify the regulators of MHC-II, we conducted data-mining of the transcriptomic and proteomic data from Cancer Cell Line Encyclopedia (CCLE) and multiple melanoma clinical cohorts. We found that a higher cancer-cell-intrinsic MHC-II level is significantly associated with better anti-PD-1 response, and that the Hippo signaling pathway can regulate MHC-II expression in melanoma cells. Our findings provide preclinical rationales for increasing cancer cell MHC-I/MHC-II expression to enhance sensitivity to immunotherapy. Citation Format: Shengqing Gu, Wubing Zhang, Xiaoqing Wang, Peng Jiang, Gordon J. Freeman, Scott J. Rodig, Henry Long, Benjamin E. Gewurz, F. Stephen Hodi, X. Shirley Liu, Myles Brown. Integrative approaches to modulate antigen presentation and boost cancer immune response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB098.

Abstract 6131: Harnessing resveratrol-mediated restoration of MHC-I in melanoma to enhance immunotherapy

Abstract The introduction of immunotherapy has drastically improved outcomes in cancer therapy, particularly in melanoma, the deadliest form of skin cancer. However, around half of melanoma tumors are initially resistant to treatment and a significant proportion of initial responders gain resistance later. This is in part because tumors are able to decrease their ability to be recognized by T-cells, an essential actor in immunotherapeutic action. There are two major types of T-cells: CD4+ helper and CD8+ cytotoxic. The most common method used by tumor cells to evade immune attack is to down-regulate major histocompatibility complex (MHC) class I molecules, which allow CD8+ T-cells to recognize cells to be eliminated. Thus, to increase immunotherapeutic efficacy, it is critical to identify how to safely restore MHC-I expression on cancer cells so that tumor antigens are presented to T-cells. I focused on finding potential adjuvants to immunotherapy for this purpose, and I found that resveratrol, a natural compound found in plants and associated with various medicinal properties, consistently elevated MHC-I expression in melanoma cells. Through a proteomics study, I identified that resveratrol also significantly affected pathways known to enhance MHC-I expression. Citation Format: Lauren C. Morehead, Brian S. Koss, Isabelle R. Miousse, Alan J. Tackett. Harnessing resveratrol-mediated restoration of MHC-I in melanoma to enhance immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6131.

Effects of prolonged exposure to ELF-EMF on HERVs expression in human melanoma cells.

The Human endogenous retroviruses (HERVs) are ancient remnants of exogenous retroviral infections. Their abnormal activation is associated with several diseases, such as cancer and autoimmunity. Epigenetic and environmental factors are probably playing essential roles in the expression of these elements. This study aimed to examine the 96-hour effects of ELF-EMF on HERV-H, K, and W expression in human melanoma cells. SK-MEL-37 cells (the human skin malignant melanoma) were continuously exposed to ELF-EMF (50 Hz) at 1.5 and 3 mT intensity for 96 hours. Following mRNA extraction, the expression level of HERV-H, K, and W was assessed by qPCR. According to our results, exposure to ELF-EMF intensities for 96 hours could significantly downregulate HERV-H, K, and W env gene expression (P<0.001). Our obtained data suggest that low intensity and long-term exposure to ELF-EMF may pave using this type of radiation as a novel therapeutic approach by neutralizing the HERVs upregulated expression in melanoma cells.

Disruption of Redox Homeostasis by Alterations in Nitric Oxide Synthase Activity and Tetrahydrobiopterin along with Melanoma Progression.

Cutaneous melanoma emerges from the malignant transformation of melanocytes and is the most aggressive type of skin cancer. The progression can occur in different stages: radial growth phase (RGP), vertical growth phase (VGP), and metastasis. Reactive oxygen species contribute to all phases of melanomagenesis through the modulation of oncogenic signaling pathways. Tetrahydrobiopterin (BH4) is an important cofactor for NOS coupling, and an uncoupled enzyme is a source of superoxide anion (O2•−) rather than nitric oxide (NO), altering the redox homeostasis and contributing to melanoma progression. In the present work, we showed that the BH4 amount varies between different cell lines corresponding to distinct stages of melanoma progression; however, they all presented higher O2•− levels and lower NO levels compared to melanocytes. Our results showed increased NOS expression in melanoma cells, contributing to NOS uncoupling. BH4 supplementation of RGP cells, and the DAHP treatment of metastatic melanoma cells reduced cell growth. Finally, Western blot analysis indicated that both treatments act on the PI3K/AKT and MAPK pathways of these melanoma cells in different ways. Disruption of cellular redox homeostasis by the altered BH4 concentration can be explored as a therapeutic strategy according to the stage of melanoma.

Role of GILT and MHC class II in melanoma cells on regulating the anti-tumor immune response

Abstract The MHC class I antigen presentation pathway in melanoma cells has a well-established role in immune-mediated destruction of melanoma. However, the role of the MHC class II pathway in melanoma cells is not fully understood. Gamma-interferon-inducible lysosomal thiol reductase (GILT) is critical for MHC class II-restricted presentation of multiple melanoma antigens by antigen presenting cells. While GILT and MHC class II expression is typically limited to antigen presenting cells, GILT and MHC class II can be expressed constitutively or induced by IFN-γ in melanoma cells. In human melanoma specimens, high GILT expression and an active and intact MHC class II pathway are associated with improved survival. The goal of this project is to investigate a causal role for GILT and MHC class II in melanoma cells, using Yale University Mouse Melanoma (YUMM) lines YUMM2.1, YUMMER1.7, and YUMMERG. These cell lines constitutively expressed GILT, and MHC class II expression was IFN-γ-inducible in a subset of cells under serum-free conditions. We have genetically engineered GILT−/− YUMM2.1 cells and MHC class II (H2Ab1)−/− YUMM2.1 cells via CRISPR/Cas9 and verified the deletion. We have generated lentiviral constructs expressing GILT alone, CIITA alone, and dual expression of H2Ab1 and CIITA, to allow for the generation of melanoma cell lines with and without GILT and MHC class II. Transduction of GILT−/− YUMM2.1 cells with GILT resulted in high transduction efficiency and overexpression. Thus, we have developed models to determine the effect of GILT and MHC class II expression in melanoma cells on regulating in vivo tumor growth and the anti-tumor immune response. This work was supported by a Basic Science Award from the Harry J. Lloyd Charitable Trust and a Merit Review Award I01-BX005336 from the US Department of Veterans Affairs (VA), Biomedical Laboratory Research and Development Service (K.T.H.). The contents do not represent the views of the VA or the US Government.

High GILT Expression Is Associated with Improved Survival in Metastatic Melanoma Patients Treated with Immune Checkpoint Inhibition.

Simple SummarySkin cancer is the most common type of cancer, with melanoma being among the deadliest of skin cancers due to its propensity to metastasize. Immune checkpoint inhibitors (ICI) generate anti-tumor immune responses resulting in improved outcomes in patients with metastatic melanoma. However, only a subset of melanoma patients responds to these therapies, which are costly and come with a risk of adverse effects. Therefore, there is a need for biomarkers to predict which patients will respond to ICI. We found that ICI-treated metastatic melanoma patients with high GILT mRNA expression in bulk tumor samples had improved survival. Additionally, high GILT protein expression within metastatic melanoma cells was associated with improved survival in patients treated with ICI. This study suggests that GILT may serve as a biomarker to predict which patients will respond to ICI, which could improve patient care, reduce healthcare costs, and facilitate appropriate selection of therapies for patients with metastatic melanoma.Gamma-interferon-inducible lysosomal thiol reductase (GILT) is critical for MHC class II restricted presentation of multiple melanoma antigens. There is variable GILT protein expression in malignant melanocytes in melanoma specimens. High GILT mRNA expression in melanoma specimens is associated with improved overall survival, before the advent of immune checkpoint inhibitors (ICI). However, the association of GILT in metastatic melanoma with survival in patients treated with ICI and the cell type expressing GILT associated with survival have not been determined. Using RNA sequencing datasets, high GILT mRNA expression in metastatic melanoma specimens was associated with improved progression-free and overall survival in patients treated with ICI. A clinical dataset of metastatic melanoma specimens was generated and annotated with clinical information. Positive GILT immunohistochemical staining in antigen presenting cells and melanoma cells was observed in 100% and 65% of metastatic melanoma specimens, respectively. In the subset of patients treated with ICI in the clinical dataset, high GILT protein expression within melanoma cells was associated with improved overall survival. The association of GILT mRNA and protein expression with survival was independent of cancer stage. These studies support that high GILT mRNA expression in bulk tumor samples and high GILT protein expression in melanoma cells is associated with improved survival in ICI-treated patients. These findings support further investigation of GILT as a biomarker to predict the response to ICI.

KLF10 upregulates ACSM3 via the PI3K/Akt signaling pathway to inhibit the malignant progression of melanoma.

Malignant melanoma is a type of skin cancer caused by mutations in the DNA of melanocytes. Melanoma is relatively rare compared with other types of skin tumors, but has a highly aggressive biological behavior and consequently, a poorer prognosis. Therefore, the present study aimed to explore the role and mechanism of Kruppel-like factor 10 (KLF10) and acyl-CoA medium-chain synthetase 3 (ACSM3) in melanoma progression. KLF10 expression in melanoma tissues was predicted using Gene Expression Profiling Interactive Analysis (GEPIA). KLF10 expression in healthy and melanoma cells was also detected using reverse transcription-quantitative PCR and western blotting. Cell transfection was performed to overexpress KLF10 or silence ACSM3. Cell viability, proliferation, migration, invasion and apoptosis were detected using Cell Counting Kit-8, colony formation, wound healing, Transwell and TUNEL assays, respectively. The activity of the ACSM3 promoter was detected using a dual-luciferase reporter assay, and the relationship between KLF10 and ACSM3 was detected using the GEPIA database and chromatin immunoprecipitation (ChIP). The results demonstrated that KLF10 expression was significantly downregulated in melanoma cells, especially in A375 cells. Compared with the Ov-NC group, KLF10 overexpression significantly inhibited the proliferation, invasion and migration of melanoma cells and promoted their apoptosis. Similar to KLF10, ACSM3 was also downregulated in A375 cells compared with that in the HEM group, and the GEPIA database analysis and ChIP assay results demonstrated that KLF10 expression was positively associated with ACSM3 expression. Furthermore, silencing ACSM3 significantly reversed the effect of KLF10 overexpression on cell proliferation, invasion and migration, and ACSM3 knockdown increased the levels of phosphorylated (p)-PI3K and p-Akt compared with the levels in the Ov-KLF10 + sh-NC group. Overall, the present study suggested that KLF10 inhibited the proliferation, invasion and migration of melanoma cells by targeting ACSM3 via the PI3K/Akt signaling pathway.

Nobiletin Induces Ferroptosis in Human Skin Melanoma Cells Through the GSK3β-Mediated Keap1/Nrf2/HO-1 Signalling Pathway.

Melanoma is an aggressive malignant skin tumour with an increasing global incidence. However, current treatments have limitations owing to the acquired tumour drug resistance. Ferroptosis is a recently discovered form of programmed cell death characterised by iron accumulation and lipid peroxidation and plays a critical role in tumour growth inhibition. Recently, ferroptosis inducers have been regarded as a promising therapeutic strategy to overcome apoptosis resistance in tumour cells. In this study, we reported that nobiletin, a natural product isolated from citrus peel, and exhibited antitumour activity by inducing ferroptosis in melanoma cells. Subsequently, we further explored the potential mechanism of nobiletin-induced ferroptosis, and found that the expression level of glycogen synthase kinase 3β (GSK3β) in the skin tissue of patients with melanoma was significantly reduced compared to that in the skin of normal tissue. Additionally, nobiletin increased GSK3β expression in melanoma cells. Moreover, the level of Kelch-like Ech-associated protein-1 (Keap1) was increased, while the level of nuclear factor erythroid 2-related factor 2 (Nrf2), and haem oxygenase-1 (HO-1) was decreased in nobiletin-treated melanoma cells, suggesting that the antioxidant defence system was downregulated. Furthermore, knockdown of GSK3β significantly reduced nobiletin-induced ferroptosis and upregulated the Keap1/Nrf2/HO-1 signalling pathway, while the opposite was observed in cells overexpressing GSK3β. In addition, molecular docking assay results indicated that nobiletin showed strong binding affinities for GSK3β, Keap1, Nrf2, and HO-1. Taken together, our results demonstrated that nobiletin could induce ferroptosis by regulating the GSK3β-mediated Keap1/Nrf2/HO-1 signalling pathway in human melanoma cells. Hence, nobiletin stands as a promising drug candidate for melanoma treatment with development prospects.

ZEB1 transcription factor promotes immune escape in melanoma

BackgroundThe efficacy of immunotherapies in metastatic melanoma depends on a robust T cell infiltration. Oncogenic alterations of tumor cells have been associated to T cell exclusion. Identifying novel cancer cell-intrinsic...

SPAG9 promotes the migration and invasion of melanoma cells by regulating the MAPK pathway

&#x0D; &#x0D; &#x0D; &#x0D; Purpose: To determine the regulatory role of sperm-associated antigen 9 (SPAG9) in melanoma cell growth.&#x0D; Methods: Immunohistochemical analysis was performed to investigate SPAG9 expression in melanoma tissues. Western blot was used to evaluate SPAG9 expression in melanoma tissues and cells. Melanoma cells were transfected with an siRNA targeting SPAG9 or a SPAG9 overexpression vector. Cell migration and invasion were examined by wound healing and transwell assays. The effects of SPAG9 on the epithelial-mesenchymal transition and mitogen-activated protein kinase (MAPK) pathway in melanoma cells were assessed by western blot.&#x0D; Results: SPAG9 expression was enhanced in melanoma tissues and cells. SiRNA-mediated silencing of SPAG9 repressed melanoma cell migration and invasion, and SPAG9 overexpression contributed to melanoma cell metastasis. In melanoma cells transfected with siRNA-SPAG9, E-cadherin expression decreased while vimentin and matrix metalloproteinase (MMP)-2/9 expression increased. However, ectopic expression of SPAG9 reversed this expression of E-cadherin, vimentin, and MMP-2/9. Silencing of SPAG9 decreased the phosphorylation of MAPKs, including p-p38, p-ERK and p-JNK, in melanoma cells. SPAG9 overexpression upregulated phosphorylation of MAPKs.&#x0D; Conclusion: SPAG9 promotes the migration and invasion of melanoma cells by activating the MAPK pathway.&#x0D; &#x0D; &#x0D; &#x0D;