Melanoma Tissues Research Articles

TIPE2 inhibits melanoma progression through MEK/ERK signaling.

Recent studies have uncovered that TIPE2 is involved in the development of cancer. However, less research has been conducted on the role of TIPE2 in melanoma. Our study aims to elucidate the mechanism of action of TIPE2 in the development of melanoma. We examined TIPE2 expression in paracarcinoma tissue and melanoma tissues and found that TIPE2 expression was downregulated in melanoma tissue compared with paracarcinoma tissue. Overexpression of TIPE2 significantly inhibited the proliferation of melanoma cells in vitro and even inhibited tumor formation in vivo. The CCK8 assay results indicated that TIPE2 overexpression suppressed the proliferation of melanoma cells. The colony-forming ability and wound healing ability of TIPE2-overexpressing melanoma cells were significantly reduced compared with those of control cells. Moreover, immunohistochemistry experiments using a nude mouse tumor model showed consistent results. TIPE2 inhibited the phosphorylation of MEK and ERK. In summary, TIPE2 suppresses the proliferation and migration of melanoma cells by affecting proliferation-related factors and possibly by regulating the MEK/ERK pathway. TIPE2 could be used to inhibit melanoma growth and is a potential drug target for future drug development.

Significance of the preferentially expressed antigen in melanoma in discriminating the conjunctival malignant melanoma and pigmented nevus

Objective: To investigate the significance of the preferentially expressed antigen in melanoma (PRAME) in the differential diagnosis of the conjunctival malignant melanoma and pigmented nevus. Methods: Specimens from 86 patients with conjunctival malignant melanoma (42 males and 44 females, aged 18 to 84 years) and 86 patients with conjunctival pigmented nevus (47 males and 39 females, aged 1 to 82 years) were collected at Zhongshan Ophthalmic Center, Sun Yat-sen University from January 2017 to July 2024. Immunohistology was performed to detect the PRAME expression. The difference of PRAME expression in the two kinds of conjunctival melanocyte hyperplasia lesions and the correlation of PRAME expression with clinical stages of the conjunctival malignant melanoma (T1 to T4) were analyzed. Results: Most patients with malignant melanoma had a positive PRAME expression (89.53%, 77/86), while only 1 patient with pigmented nevus showed a positive PRAME expression (1.16%, 1/86). The positive expression rate of the PRAME in conjunctival malignant melanoma tissues was significantly higher than that in conjunctival pigmented nevi (P<0.05). The PRAME had a sensitivity and specificity of 89.53% and 98.84%, respectively. The expression of the PRAME among patients with conjunctival malignant melanoma in different age groups (>50, 30 to 50, <30) was significantly different (P<0.05). However, the PRAME expression had no difference in different clinical stages of the conjunctival malignant melanoma (P>0.05). Conclusions: The PRAME has significance in discriminating the conjunctival malignant melanoma and pigmented nevus. It is a useful biomarker in the diagnosis of conjunctival malignant melanoma.

High BRAF V600 Mutation Level Associated with Worse Outcome in Metastatic Melanoma Patients Receiving BRAF and MEK Inhibitors.

The prognostic value of BRAF V600 mutation level on clinical outcomes in patients with BRAF V600-mutated metastatic melanoma treated with BRAF and MEK inhibitors remains uncertain. The association was retrospectively analysed between BRAF V600 mutation level (defined as the ratio of the quantification of the BRAF V600 allele to the percentage of tumoral cells in the sample analysed) and progression-free and overall survival (PFS and OS, respectively) and 3-month response rate in a cohort of 58 patients with metastatic melanoma who harboured BRAF V600E/K mutations and received dual targeted-therapy BRAF/MEK inhibitors. The BRAF mutation level cut-off determined by the area under the receiver operating characteristic curve after internal validation by bootstrap methods was 0.44. Risk of poor PFS and OS was associated with BRAF V600 mutation level > 0.44 on multivariate analysis (p = 0.02 and p = 0.02, respectively) after adjusting for major confounding factors (age, sex, lactate dehydrogenase level, brain metastasis, and treatment line). No association was found between BRAF mutation level and 3-month response rate. Our study shows that high BRAF V600 mutation level in melanoma tissue was associated with poor prognosis in patients with metastatic melanoma treated with BRAF and MEK inhibitors.

DTL promotes the growth and migration of melanoma cells through the ERK/E2F1/BUB1 axis

Melanoma is the most dangerous form of skin cancer. Hence, a better understanding of molecular mechanisms in melanoma pathogenesis is urgently needed, which provides a new insight into the therapy of melanoma. DTL gene is screened out in melanoma pathogenesis by integrated bioinformatics analysis, and its expression is validated in the tissue and cell samples of melanoma. Forced DTL expression facilitates the proliferation, invasion, migration and EMT of melanoma cells, while DTL knockdown suppresses the biological behavior of melanoma cells. In addition, DTL promotes the malignancy of melanoma in vivo. Mechanistically, BUB1 is the crucial downstream target of DTL. Reduced DTL expression suppresses BUB1 expression, while enhanced DTL expression induces BUB1 upregulation. Rescue experiments showed that growing and migrating of melanoma cells induced by DTL are partially impaired by BUB1 inhibition. In addition, the expression of phosphorylated ERK (p-ERK) and the downstream transcription factor E2F1 are reduced when DTL expression is blocked. Meanwhile, BUB1 levels are decreased when the expression of p-ERK or E2F1 is repressed. Notably, the growth and migration of melanoma cells by inhibition of ERK and knockdown of E2F1 was rescued by overexpressing BUB1. DTL gene may be a prognosis marker and represent a unique potential target for melanoma patients. DTL supports the biologically malignant activity of melanoma cells via the ERK/E2F1/BUB1 axis.

Filamentous phages as tumour-targeting immunotherapeutic bionanofibres.

Programmed cell death-ligand 1 (PD-L1) blockers have advanced immunotherapy, but their lack of tumour homing capability represents a substantial challenge. Here we show that genetically engineered filamentous phages can be used as tumour-targeting immunotherapeutic agents that reduce the side effects caused by untargeted delivery of PD-L1 blockers. Specifically, we improved biopanning to discover a peptide binding the extracellular domain of PD-L1 and another targeting both melanoma tissues and cancer cells. The two peptides were genetically fused to the sidewall protein and tip protein of fd phages, respectively. The intravenously injected phages homed to tumours and bound PD-L1 on cancer cells, effectively blocking PD-1/PD-L1 recognition to trigger targeted immunotherapy without body weight loss, organ abnormalities and haematological aberrations. The phages, cost-effectively replicated by bacteria, are cancer-targeting immunotherapeutic nanofibres that can be flexibly designed to target different cancer types and immune checkpoints.

Deep Learning With Optical Coherence Tomography for Melanoma Identification and Risk Prediction.

Malignant melanoma is the most severe skin cancer with a rising incidence rate. Several noninvasive image techniques and computer-aided diagnosis systems have been developed to help find melanoma in its early stages. However, most previous research utilized dermoscopic images to build a diagnosis model, and only a few used prospective datasets. This study develops and evaluates a convolutional neural network (CNN) for melanoma identification and risk prediction using optical coherence tomography (OCT) imaging of mice skin. Longitudinal tests are performed on four animal models: melanoma mice, dysplastic nevus mice, and their respective controls. The CNN classifies melanoma and healthy tissues with high sensitivity (0.99) and specificity (0.98) and also assigns a risk score to each image based on the probability of melanoma presence, which may facilitate early diagnosis and management of melanoma in clinical settings.

Expression of Markers Associated with Epithelial-Mesenchymal Transition and Extracellular Matrix Degradation in Human Uveal Melanoma.

The expression of markers associated with epithelial-mesenchymal transition (EMT) and extracellular matrix degradation in human uveal melanoma tissue samples and postequatorial zone of the choroid was assessed by immunohistochemical staining. Increased expression of EMT markers E-cadherin and vimentin was observed in the tumor. The ratio of MMP-9 to TIMP-1 proteins related to the extracellular matrix degradation was higher in the tumor. These results may indicate activation of EMT-like process in the uveal melanoma cells and degradation of the extracellular matrix, which can contribute to the development of collective invasion in uveal melanoma.

Immunohistochemistry for assessing toxicity and mechanism of action of anticancer drugs during preclinical trials. From theory to practice

Aim. To identify the most suitable pathogenetic mechanisms for in-depth study of the antitumor and antimetastatic effects of tested hybrid organotin compounds using the immunohistochemical approach.Materials and Methods. Here, we tested bis(3,5-di-tert-butyl-4-hydroxyphenylthiolate) dimethyltin (laboratory code Me-3), belonging to the class of hybrid organotin compounds, on 30 female C57Bl/6 mice using a universal model of transplantable tumors with spontaneous metastasis (B16 melanoma). 48 hours after tumor cell transplantation, we intraperitoneally administered Me-3 once daily to female C57Bl/6 mice for 10 days at a total dose (TD) of 375 mg/kg. For histological analysis, we used the primary tumor node of B16 melanoma. Immunophenotyping of B16 melanoma tissue samples was carried out using the polyclonal antibodies to transforming growth factor beta 1 (TGFβ-1), vascular endothelial growth factor A (VEGFA), Bcl2-associated X Protein (Bcl-2), cluster of differentiation 34 (CD34).Results. After the exposure to Me-3, we found a reduced immunohistochemical signal to TGF-β1 and Bcl-2 3 in the tumor tissue. Low doses of Me-3 have also impacted angiogenesis.Conclusion. Me-3 has a pro-apoptotic and anti-angiogenetic effects on B16 melanoma cells in C57Bl/6 mice.

Local anesthetic tetracaine hydrochloride induces pyroptosis via caspase-3/gasdermin E in uveal melanoma

BackgroundEvasion of pyroptosis is an effective survival strategy employed by cancer cells to evade immune cell attacks and drug-induced cytotoxicity. Exploring potent molecules capable of inducing pyroptosis in cancer cells has significant clinical implications for the control of cancer progression. Unexpectedly, we found that the local anesthetic tetracaine hydrochloride (TTC) induced pyroptosis, specifically in uveal melanoma but not in acral or cutaneous melanoma. MethodsWe investigated the effects of TTC on various melanoma cell lines and performed transcriptome sequencing of TTC-treated uveal melanoma cells. The role of gasdermin E (GSDME), an executive protein responsible for pyroptosis, was explored using CRISPR-Cas13d knockdown, caspase-3 inhibitor treatment, and western blot analysis. Differential gene expression and pathway enrichment analyses were performed. Furthermore, we used tissue microarrays to assess GSDME expression levels in melanoma tissues from different anatomical sites. ResultsTTC significantly induced pyroptosis specifically in uveal melanoma cells with high GSDME expression levels. TTC treatment could lead to GSDME cleavage by the caspase-3 in uveal melanoma C918 cells. GSDME knockdown or caspase-3 inhibition suppressed TTC-induced pyroptosis. Transcriptome analysis revealed differentially expressed genes enriched in signaling pathways related to pyroptosis, immunity, and cytokines. ConclusionsThis study showed that the local anesthetic TTC effectively induces pyroptosis in uveal melanoma through the caspase-3/GSDME pathway, highlighting its potential application in immunotherapy. Notably, the use of TTC has potential as an agent for inducing pyroptosis and as an adjuvant anticancer therapy in uveal melanoma.

Application of Different Staining Methods in the Diagnosis of Pigment-Rich Melanoma.

To compare the application of different treatments in the diagnosis of melanoma with severe pigment interference, to solve the problem of pigment interference with immunohistochemical interpretation. The pigment-rich melanomas were first depigmented with potassium permanganate using a concentration gradient (0.1%, 0.5%, 1%) and a time gradient (1, 5, 10, 15, 30 min, 6 h), and the optimal concentration and time were found. Then, 12 cases of pigment-rich melanoma tissues were collected, and the tissues were stained with diaminobenzidine (DAB), alkaline phosphatase-fast red (AP red), multiplex immunofluorescence (MIF), and 3-amino-9-ethylcarbazole (AEC), and ferrous sulfate, comparing different methods, positive expression of HMB45, MelanA, S100, SOX10, ki67. First, the concentration of 0.5% potassium permanganate after 15 min treatment of the pigment significantly faded, and the intensity of antibody positivity was better than other concentrations and time. Second, after depigmentation treatment, the antibody positivity rate was 41.7%-66.7% for DAB, 66.7%-91.7% for AP red, 83.3%-100% for multiplex immunofluorescence, 25%-33.3% for AEC, and 33.3% for ferrous sulfate. AP red staining and mIF are more suitable for the diagnosis of melanoma with severe pigment interference, and AP red staining is more economical and practical.

LncRNA SLNCR1 facilitates angiogenesis and tumor growth in melanoma via DNMT1‐mediated epigenetically silencing SPRY2

AbstractBackgroundThe malignancy of melanoma is attributed to its pronounced invasiveness, extensive vascularization, and rapid tumor cell growth and metastasis. LncRNA SLNCR1 is closely associated with a variety of aggressive tumors. However, our understanding of SLNCR1 influences on malignant melanoma growth metastasis mechanism especially proangiogenic mechanism remains unclear.MethodsThe expression of SLNCR1 was evaluated in melanoma tissues, adjacent tissues, melanoma cell lines. The abilities of SLNCR1 on proliferation, migration, and angiogenesis of HUVECs were detected by CCK‐8, flow cytometry, and Western blot assays. The association between SLNCR1, DNMT1, and SPRY2 was assessed by ChIP, RIP, and Western blot assays. The effect of SLNCR1 on tumor growth was determined using a xenograft model in nude mice.ResultsSLNCR1 was confirmed to be highly expressed in melanoma tissues and cells. CM from melanoma cells transfected with sh‐SLNCR1 attenuated proliferation, migration, and angiogenesis of HUVECs. Moreover, loss of SLNCR1 hindered tumor growth and metastasis, as evidenced by reduced tumor size and weight, as well as angiogenesis. Mechanistic studies revealed that SLNCR1 silenced SPRY2 expression, likely through enhancing DNMT1‐mediated DNA methylation of SPRY2 promoter.ConclusionSLNCR1 is an oncogene that interacts with DNMT1 to mediate SPRY2 methylation, thereby suppressing SPRY2 expression and promoting the angiogenesis and tumor growth in melanoma. SLNCR1 may serve as a potential target for melanoma treatment.

Hepatocyte growth factor promotes melanoma metastasis through ubiquitin-specific peptidase 22-mediated integrins upregulation

Hepatocyte growth factor (HGF) plays a critical role in promoting tumor migration, invasion, and metastasis, partly by upregulating integrins. The molecular mechanisms behind how HGF facilitates integrin-mediated tumorigenesis are not fully understood. In this study, we demonstrate that the ubiquitin-specific peptidase 22 (USP22) is essential for HGF-induced melanoma metastasis. HGF treatment dramatically increased the expression of both USP22 and multiple integrin family members in particular ITGAV, ITGB3, and ITGA1. An unbiased analysis of the TCGA database reveals integrins as common downstream targets of both USP22 and HGF across multiple human cancer types. Notably, CRISPR-mediated deletion of USP22 completely eliminates HGF-induced integrin expression in melanoma cells. At the molecular level, USP22 acts as a bona fide deubiquitinase for Sp1, a transcription factor for the ITGAV, ITGB3, and ITGA1 genes. USP22 interacts with and inhibits Sp1 ubiquitination, protecting against Sp1 proteasomal degradation. Supporting this, immunohistology analysis detects a positive correlation among USP22, Sp1, and integrin αv in human melanoma tissues. This study identifies the death from the signature gene USP22 as a critical positive regulator for HGF-induced integrin expression by deubiquitinating the Sp1 transcription factor during melanoma metastasis.

LPA suppresses HLA-DR expression in human melanoma cells: a potential immune escape mechanism involving LPAR1 and DR6-mediated release of IL-10.

While immune checkpoint inhibitors (ICIs) are promising in the treatment of metastatic melanoma, about half of patients do not respond well to them. Low levels of human leukocyte antigen-DR (HLA-DR) in tumors have been shown to negatively influence prognosis and response to ICIs. Lysophosphatidic acid (LPA) is produced in large amounts by melanoma and is abundantly present in the tumor microenvironment. LPA induces the release of various cytokines and chemokines from tumor cells, which affect cancer development, metastasis, and tumor immunity. In the present study, we investigated the role of LPA-induced IL-10 release in regulating HLA-DR expression and the underlying mechanisms in human melanoma cells. We showed that LPA (0.001-10 μM) dose-dependently increased DR6 transcript levels through activating LPAR1 in HEK293T cells. Knockdown of NF-κB1 abrogated the LPA-increased DR6 expression without affecting basal DR6 expression in both A2058 and A375 melanoma cell lines. LPA (10 µM) significantly increased IL-10 transcripts in A2058 and A375 melanoma cells, the effect was abolished by pharmacological inhibition of LPAR1 or knockdown of DR6. We found a statistically significant correlation between the expression of LPAR1, DR6 and IL-10 in human melanoma tissue and an association between increased expression of LPAR1 and reduced effectiveness of ICI therapy. We demonstrated that LPA (10 µM) markedly suppressed HLA-DR expression in both A375 and A2058 melanoma cells via activating the LPAR1-DR6-IL-10 pathway. These data suggest that the LPAR1-DR6-IL-10 autocrine loop could constitute a novel mechanism used by tumor cells to evade immunosurveillance by decreasing HLA-DR expression.

A lipid metabolism-related gene model reveals the prognosis and immune microenvironment of cutaneous melanoma

Abstract Objectives Lipid metabolic dysregulation plays a critical role in the biological behavior of skin cutaneous melanoma (SKCM). Hence, we aimed to identify lipid metabolism-related genes (LMGs) and possible prognostic models for SKCM, perform prognostic risk assessment, and predict possible effective therapies. Methods SKCM patient data were downloaded from The Cancer Genome Atlas (TCGA) and used as the training set; GSE65904 was used as the validation dataset. A prognostic risk model was established by multivariate Cox regression analysis and the LASSO algorithm. The samples in training and validation sets were grouped into high- and low-risk groups, respectively, in accordance with the risk model, and risk score (RS) distribution and survival ROC curve were obtained. The ‘limma’ package in R3.6.1 Version 3.34.7 was used to filter significant differentially expressed genes (DEGs) in the training set between the high- and low-risk groups. For DEGs, functional enrichment and immune infiltration analyses were used to reveal potential disease mechanisms and responses to immunotherapy. The expression level of LMGs involved in the prognostic risk was verified by diverse methods. Results A predictive model comprising four LMGs, including ADH4, ALDH7A1, HADH, and HADHA, was established to predict SKCM patient survival. Functional enrichment has revealed enriched immune-associated pathways. Different immune microenvironments were identified by immune infiltration analysis. HPA immunohistochemical analysis, Real-time PCR analysis, and Western blotting revealed the upregulation of HADH and HADHA and the downregulation of ADH4 and ALDH7A1 in melanoma tissues or cell lines compared to normal skin tissues and melanocyte cells. Conclusions LMGs, including ADH4, ALDH7A1, HADH, and HADHA involved in the predictive model may play a critical role in the biological behaviors and therapeutic response of melanoma. The model we constructed may serve as a prospective biological marker to predict the prognosis and therapeutic response of melanoma patients.

The prognostic implications of cuproptosis-related gene signature and the potential of PPIC as a promising biomarker in cutaneous melanoma.

Cutaneous melanoma is the most lethal of all skin tumors. Recently, cuproptosis, a novel form of cell death linked to oxidative phosphorylation, has emerged as an important factor. However, the precise role of cuproptosis in melanoma remains unclear. Our research explored the potential links between cuproptosis-related genes, prognosis, immune microenvironments, and melanoma treatments. Significantly, cuproptosis regulators showed remarkable differences between melanoma and normal tissues, establishing their relevance to melanoma. The newly developed cuproptosis-related gene signature (CGS) demonstrated a robust ability to predict overall survival (OS) in melanoma. We constructed a novel nomogram that combined clinical features with CGS to improve predictive accuracy. In addition, the study revealed correlations between CGS and immune cell populations, including CD8+T cells, Tfh cells, B cells, and myeloid-derived suppressor cells. Within the CGS, Peptidylprolyl isomerase C (PPIC) emerged as the most strongly associated with poor prognosis and drug resistance in melanoma. PPIC was identified as a promoter of melanoma progression, enhancing cell invasiveness while concurrently suppressing CD8+T cell activation. This comprehensive study not only elucidated the intricate connections between CGS, melanoma prognosis, immune microenvironment, and drug resistance but also provided compelling evidence supporting PPIC as a promising biomarker for predicting OS in melanoma treatment.

LDH-Indomethacin Nanoparticles Antitumoral Action: A Possible Coadjuvant Drug for Cancer Therapy.

Indomethacin (INDO) has a mechanism of action based on inhibiting fatty acids cyclooxygenase activity within the inflammation process. The action mechanism could be correlated with possible anticancer activity, but its high toxicity in normal tissues has made therapy difficult. By the coprecipitation method, the drug carried in a layered double hydroxides (LDH) hybrid matrix would reduce its undesired effects by promoting chemotherapeutic redirection. Therefore, different samples containing INDO intercalated in LDH were synthesized at temperatures of 50, 70, and 90 °C and synthesis times of 8, 16, 24, and 48 h, seeking the best structural organization. X-ray diffraction (XRD), vibrational Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), spectrophotometric analysis in UV-VIS, and differential thermogravimetric analysis (TGA/DTA) were used for characterization. Our results indicate that higher temperatures and longer synthesis time through coprecipitation reduce the possibility of INDO intercalation. However, it was possible to establish a time of 16 h and a temperature of 50 °C as the best conditions for intercalation. In vitro results confirmed the cell viability potential and anticancer activity in the LDH-INDO sample (16 h and 50 °C) for gastric cancer (AGP01, ACP02, and ACP03), breast cancer (MDA-MB-231 and MCF-7), melanoma (SK-MEL-19), lung fibroblast (MRC-5), and non-neoplastic gastric tissue (MN01) by MTT assay. Cell proliferation was inhibited, demonstrating higher and lower toxicity against MDA-MB-231 and SK-MEL-19. Thus, a clinical redirection of INDO is suggested as an integral and adjunctive anticancer medication in chemotherapy treatment.

Death associated protein like 1 acts as a novel tumor suppressor in melanoma by increasing the stability of P21 protein.

Melanoma is a primary malignant tumor with high lethality, which occurs in the skin and eye tissues, while the molecular mechanisms of melanomagenesis remain largely unknown. Here, we show that death-associated protein-like 1 (DAPL1) expression is lower in melanoma tissues than in paracancerous tissues or nevus tissues, and Uveal melanoma patients with lower DAPL1 expression have a poorer survivalrate than those with higher expression of DAPL1. Overexpression of DAPL1 inhibits proliferation of cultured melanoma cells, whereas knockdown of DAPL1 increases cell proliferation. Tumor transplantation experiment results also demonstrate that DAPL1 inhibits tumorigenesis of melanoma cells both in subretinal and subcutaneous tissues of nude mice in vivo. Finally, DAPL1 inhibits proliferation of melanoma cells by increasing the protein level of P21 via decreasing the ubiquitin mediated degradation of P21 and promoting its stability. Conversely, knockdown of P21 neutralizes the effects of inhibition of DAPL1 on melanoma cell proliferation and enhances the severity of melanoma tumorigenesis. These results suggest that DAPL1 is a novel melanoma tumor suppressor gene and thus a potential therapeutic target for melanoma.

Shortened progression free and overall survival to immune-checkpoint inhibitors in BRAF-, RAS- and NF1- (“Triple”) wild type melanomas

BackgroundMelanomas lacking mutations in BRAF, NRAS and NF1 are frequently referred to as “triple wild-type” (tWT) melanomas. They constitute 5–10 % of all melanomas and remain poorly characterized regarding clinical characteristics and response to therapy. This study investigates the largest multicenter collection of tWT-melanomas to date. MethodsTargeted next-generation sequencing of the TERT promoter and 29 melanoma-associated genes were performed on 3109 melanoma tissue samples of the prospective multicenter study ADOREG/TRIM of the DeCOG revealing 292 patients suffering from tWT-melanomas. Clinical characteristics and mutational patterns were analyzed. As subgroup analysis, we analyzed 141 tWT-melanoma patients receiving either anti-CTLA4 plus anti-PD1 or anti PD1 monotherapy as first line therapy in AJCC stage IV. Results184 patients with cutaneous melanomas, 56 patients with mucosal melanomas, 34 patients with acral melanomas and 18 patients with melanomas of unknown origin (MUP) were included. A TERT promoter mutation could be identified in 33.2 % of all melanomas and 70.5 % of all tWT-melanomas harbored less than three mutations per sample. For the 141 patients with stage IV disease, mPFS independent of melanoma type was 6.2 months (95 % CI: 4–9) and mOS was 24.8 months (95 % CI: 14.2–53.4) after first line anti-CTLA4 plus anti-PD1 therapy. After first-line anti-PD1 monotherapy, mPFS was 4 months (95 %CI: 2.9–8.5) and mOS was 29.18 months (95 % CI: 17.5–46.2). ConclusionsWhile known prognostic factors such as TERT promoter mutations and TMB were equally distributed among patients who received either anti-CTLA4 plus anti-PD1 combination therapy or anti-PD1 monotherapy as first line therapy, we did not find a prolonged mPFS or mOS in either of those. For both therapy concepts, mPFS and mOS were considerably shorter than reported for melanomas with known oncogene mutations.

M6A- and m5C- modified lncRNAs orchestrate the prognosis in cutaneous melanoma and m6A- modified LINC00893 regulates cutaneous melanoma cell metastasis.

As the most important modifications on the RNA level, N6-methyladenosine (m6A-) and 5-methylcytosine (m5C-) modification could have a direct influence on the RNAs. Long non-coding RNAs (lncRNAs) could also be modified by methylcytosine modification. Compared with mRNAs, the function of lncRNAs could be more potent to some extent in biological processes like tumorigenesis. Until now, rare reports have been done associated with cutaneous melanoma. Herein, we wonder if the m6A- and m5C- modified lncRNAs could influence the immune landscape and prognosis in melanoma, and we also want to find some lncRNAs which could directly affect the malignant behaviors of melanoma. Systematically, we explored the expression pattern of m6A- and m5C- modified lncRNAs in melanoma from datasets including UCSC Xena and NCBI GEO, and the prognostic lncRNAs were selected. Then, according to the expression pattern of lncRNAs, melanoma samples from these datasets were divided into several subtypes. Prognostic model, nomogram survival model, drug sensitivity, GO, and KEGG pathway analysis were performed. Furthermore, among several selected lncRNAs, we identified one lncRNA named LINC00893 and investigated its expression pattern and its biological function in melanoma cell lines. We identified 27 m6A- and m5C- related lncRNAs which were significantly associated with survival, and we made a subtype analysis of melanoma samples based on these 27 lncRNAs. Among the two subtypes, we found differences of immune cells infiltration between these two subtypes. Then, LASSO algorithm was used to screen the optimized lncRNAs combination including ZNF252P-AS1, MIAT, FAM13A-AS1, LINC-PINT, LINC00893, AGAP2-AS1, OIP5-AS1, and SEMA6A-AS1. We also found that there was a significant correlation between the different risk groups predicted based on RS model and the actual prognosis. The nomogram survival model based on independent survival prognostic factors was also constructed. Besides, sensitivity to chemotherapeutic agents, GO and KEGG analysis were performed. In different risk groups, a total of 14 drug molecules with different distributions were obtained, which included AZD6482, AZD7762, AZD8055, camptothecin, dasatinib, erlotinib, gefitinib, gemcitabine, GSK269962A, nilotinib, rapamycin, and sorafenib. A total of 55 significantly related biological processes and 17 KEGG signaling pathways were screened. At last, we noticed that LINC00893 had a relatively lower expression in melanoma tissue and cell lines compared with adjacent tissues and epidermal melanocyte, and down-regulation of LINC00893 could promote the malignant behavior of melanoma cells in A875 and MV3. In these two melanoma cell lines, down-regulation of m6A-related molecules like YTHDF3 and METTL3 could promote the expression of LINC00893. We made an analysis of m6A- and m5C- related lncRNAs in melanoma samples and a prediction of these lncRNAs' role in prognosis, tumor microenvironment, immune infiltration, and clinicopathological features. We also found that LINC00893, which is potentially regulated by m6A modification, could serve as a tumor-suppressor in melanoma and play an inhibitory role in melanoma metastasis.

Tazarotene-induced Gene 1 Induces Melanoma Cell Death by Triggering Endoplasmic Reticulum Stress Response.

This study investigated the mechanism by which tazarotene-induced gene 1 (TIG1) inhibits melanoma cell growth. The main focus was to analyze downstream genes regulated by TIG1 in melanoma cells and its impact on cell growth. The effects of TIG1 expression on cell viability and death were assessed using water-soluble tetrazolium 1 (WST-1) mitochondrial staining and lactate dehydrogenase release assays. RNA sequencing and Western blot analysis were employed to investigate the genes regulated by TIG1 in melanoma cells. Additionally, the correlation between TIG1 expression and its downstream genes was analyzed in a melanoma tissue array. TIG1 expression in melanoma cells was associated with decreased cell viability and increased cell death. RNA-sequencing (RNA-seq), quantitative reverse transcription PCR (reverse RT-QPCR), and immunoblots revealed that TIG1 expression induced the expression of Endoplasmic Reticulum (ER) stress response-related genes such as Homocysteine-responsive endoplasmic reticulum-resident ubiquitin-like domain member 1 (HERPUD1), Binding immunoglobulin protein (BIP), and DNA damage-inducible transcript 3 (DDIT3). Furthermore, analysis of the melanoma tissue array revealed a positive correlation between TIG1 expression and the expression of HERPUD1, BIP, and DDIT3. Additionally, attenuation of the ER stress response in melanoma cells weakened the impact of TIG1 on cell growth. TIG1 expression effectively hinders the growth of melanoma cells. TIG1 induces the upregulation of ER stress response-related genes, leading to an increase in caspase-3 activity and subsequent cell death. These findings suggest that the ability of retinoic acid to prevent melanoma formation may be associated with the anticancer effect of TIG1.