Human Melanoma Cells Research Articles

Expression of Concern: Fisetin Inhibits Human Melanoma Cell Invasion through Promotion of Mesenchymal to Epithelial Transition and by Targeting MAPK and NFκB Signaling Pathways.

Expression of Concern: Fisetin Inhibits Human Melanoma Cell Invasion through Promotion of Mesenchymal to Epithelial Transition and by Targeting MAPK and NFκB Signaling Pathways.

DNA-PK inhibition enhances neoantigen diversity and increases T cell responses to immunoresistant tumors.

Effective antitumor T cell activity relies on the expression and MHC presentation of tumor neoantigens. Tumor cells can evade T cell detection by silencing the transcription of antigens or by altering MHC machinery resulting in inadequate neoantigen-specific T cell activation. We identified DNA-PK inhibitor (DNA-PKi) NU7441 as a promising immunomodulator that reduced immunosuppressive proteins while increasing MHC-I expression in a panel of human melanoma cell lines. In tumor-bearing mice, combination therapy using NU7441 and immune adjuvants STING ligand and CD40 agonist (NU-SL40) substantially increased and diversified the neoantigen landscape, antigen presenting machinery, and consequently substantially increased both the number and repertoire of neoantigen-reactive tumor infiltrating lymphocytes (TILs). DNA-PK-inhibition or knockout promoted transcription and protein expression of various neoantigens in human and mouse melanomas and induced sensitivity to ICB in resistant tumors. In patients, PRKDC levels inversely correlated with MHC I expression and CD8 TILs but positively correlated with increased neoantigen loads and improved responses to ICB. These studies suggest that inhibiting DNA-PK activity can restore tumor immunogenicity by increasing neoantigen expression and presentation and broadening the neoantigen-reactive T cell population.

Identification of mutations in canine oral mucosal melanomas by exome sequencing and comparison with human melanomas

Oral mucosal melanomas (OMMs) are aggressive neoplasms commonly found in dogs but rare in humans. Utilizing whole exome sequencing (WES), which focuses on protein-coding regions to reveal mutation profiles, we conducted a comparative analysis of canine OMM and human melanomas. This study involved DNA extraction, exome enrichment, and sequencing from three canine OMM cell lines (CMGD-2, CMGD-5, TLM-1), five canine OMM frozen samples, a human OMM cell line (MEMO), and a human commercial skin melanoma cell line (SK-MEL-28). The sequencing and subsequent analysis of FASTQ files yielded final variant files, leading to the identification of mutations. Our findings revealed a total of 500 mutated genes in canine OMM, including significant ones such as EP300, FAT4, JAK3, LRP1B, NCOR1, and NOTCH1. Notably, 82 shared mutations were identified between human melanomas and canine OMM genomes. These mutations were categorized based on the gene functions. The identification of these mutations provides critical insights that can pave the way for the development of novel therapeutic strategies for both canine and human OMM, offering hope for more effective treatments in the future.

Anticancer Activity of Vitamin D, Lumisterol and Selected Derivatives against Human Malignant Melanoma Cell Lines.

Despite the recent development of improved methods of treating melanoma such as targeted therapy, immunotherapy or combined treatment, the number of new cases worldwide is increasing. It is well known that active metabolites of vitamin D3 and lumisterol (L3) exert photoprotective and antiproliferative effects on the skin, while UV radiation is a major environmental risk factor for melanoma. Thus, many natural metabolites and synthetic analogs of steroidal and secosteroidal molecules have been tested on various cancer cells and in animal models. In this study, we tested the anti-melanoma properties of several natural derivatives of vitamin D3 and L3 in comparison to 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). A significant decrease in melanoma cell proliferation and cell mobility was observed for selected derivatives, with (25R)-27-hydroxyL3 showing the highest potency (lowest IC50) in A375 cells but lower potency in SK-MEL-28 cells, whereas the parent L3 failed to inhibit proliferation. The efficacy (% inhibition) by 1,24,25(OH)3D3 and 1,25(OH)2D3 were similar in both cell types. 1,25(OH)2D3 showed higher potency than 1,24,25(OH)3D3 in SK-MEL-28 cells, but lower potency in A375 cells for the inhibition of proliferation. As for 1,25(OH)2D3, but not the other derivatives tested, treatment of melanoma cells with 1,24,25(OH)3D3 markedly increased the expression of CYP24A1, enhanced translocation of the vitamin D receptor (VDR) from the cytoplasm to the nucleus and also decreased the expression of the proliferation marker Ki67. The effects of the other compounds tested were weaker and occurred only under certain conditions. Our data indicate that 1,24,25(OH)3D3, which has undergone the first step in 1,25(OH)2D3 inactivation by being hydroxylated at C24, still shows anti-melanoma properties, displaying higher potency than 1,25(OH)2D3 in SK-MEL-28 cells. Furthermore, hydroxylation increases the potency of some of the lumisterol hydroxy-derivatives, as in contrast to L3, (25R)-27(OH)L3 effectively inhibits proliferation and migration of the human malignant melanoma cell line A375.

Hypoxia-related lncRNA correlates with prognosis and immune microenvironment in uveal melanoma

BackgroundHypoxia-related genes are linked to the prognosis of various solid malignant tumors. However, the role of hypoxia-related long non-coding RNAs (HRLs) in uveal melanoma (UVM) remains unclear. This study aimed to identify HRLs associated with UVM prognosis and develop a novel risk signature to predict patient outcomes.MethodsData from 80 UVM samples were obtained from The Cancer Genome Atlas. Prognostic HRLs were screened using Cox univariate and Pearson correlation analyses. HRL signature were constructed using Lasso analysis, and gene enrichment analysis was performed to explore the association between HRLs and immune features. Cell Counting Kit-8 assay was used to measure the propagation of human uveal melanoma (MuM2B) cells, while tumor invasion and migration were evaluated using Transwell and wound-healing experiments. Inflammatory factors and macrophage polarization were evaluated using quantitative PCR.ResultsIn total, 621 prognostic HRLs were screened and constructed in 12 HRLs. The risk score showed a significant correlation with the survival time of patients with UVM. Additionally, HRL correlated with diverse key immune checkpoints, revealing possible targets for immunotherapy. Immune-related pathways were highly enriched in the high-risk group. LINC02367, a protective HRL, was associated with the tumor microenvironment and survival time of patients with UVM. In vitro, LINC02367 significantly influenced MuM2B proliferation and migration. It also modulated macrophage polarization by regulating inflammatory factor levels, thereby affecting the immune microenvironment.ConclusionsWe developed a novel HRL signature to predict prognosis in patients with UVM. HRLs are potential biomarkers and therapeutic targets for the treatment of UVM.

Predictive Production of a New Highly Soluble Glucoside, Corylin-7-O-β-Glucoside with Potent Anti-inflammatory and Anti-melanoma Activities.

Computational tools can now facilitate screening precursors and selecting suitable biotransformation enzymes for producing new bioactive compounds. This study applied the data-mining approach to screen for candidate precursors of glycosyltransferases to produce new glucosides from 412 commercial natural compounds. Among five candidates, experimental results showed that only corylin could be glycosylated by the bacterial glycosyltransferase, BsUGT489. Analysis of interaction potential between candidates and glycosyltransferase by molecular docking tools also found that corylin was the only compatible substrate. The new glucoside was purified and confirmed to be corylin-7-O-β-glucoside. The aqueous solubility of corylin-7-O-β-glucoside was 14.2 times more than its precursor aglycone, corylin. Corylin-7-O-β-glucoside retained anti-inflammatory activity in lipopolysaccharide-induced nitric oxide production of murine macrophage RAW 264.7 cells, with an IC50 value of 121.1 ± 9.5µM. Further, corylin-7-O-β-glucoside exhibited more potent anti-melanoma activity against murine B16 and human A2058 melanoma cells than corylin. Together, predictive studies facilitate the production of a new glucoside, corylin-7-O-β-glucoside, which is highly soluble and possesses anti-inflammatory and anti-melanoma activities and therefore has promising future applications in pharmacology.

Benzoxaborinine, New Chemotype for Carbonic Anhydrase Inhibition: Ex Novo Synthesis, Crystallography, In Silico Studies, and Anti-Melanoma Cell Line Activity.

The benzoxaborinine scaffold, a homologue of benzoxaborole with an additional carbon atom in the boracycle, shows significant potential in developing new therapeutic agents. This study reports the synthesis, inhibition assays against four human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, and anti-melanoma evaluation of 7-aryl(thio)ureido-substituted benzoxaborinines. Some derivatives, particularly compound 11, exhibited potent inhibitory activity (below 65 nM) against hCA IX and XII and stronger antiproliferative effects than SLC-0111 on human melanoma cells under hypoxia. Crystallographic studies of benzoxaborinine 3 adducts with hCA I and II demonstrated the binding mode of this chemotype, revealing that although both benzoxaborinine 3 and benzoxaborole 10 share a similar zinc-binding mode, the expanded ring in benzoxaborinine led to a different orientation within the active site. These findings suggest that benzoxaborinines hold promise for designing novel carbonic anhydrase inhibitors.

Potential In Vitro Antimelanoma Effect of the Essential Oil from Croton grewioides Baill.

Cancer is a group of diseases characterized by uncontrolled cell growth, invasive capacity, and metastatic potential. Despite the continual progress in cancer treatment, high toxicity and resistance to therapy remain recurring challenges. Croton grewioides Baill. is a plant from the brazilian semi-arid region with significant pharmacological potential due to its reported antidiarrheal, antioxidant, and antitumor properties. This study evaluated the antitumor activity of the essential oil from C. grewioides leaves (CgEO) by in vitro assays. CgEO showed higher cytotoxicity in human melanoma cells (SK-MEL-28), with a 50% inhibitory concentration (IC50) of 70.0 μg/mL after 72 hours, but with low toxicity in healthy keratinocytes (HaCaT). Additionally, it was suggested that the antitumor effect of CgEO is associated with the induction of apoptosis, cell cycle alterations, and combined antioxidant action mechanisms. In conclusion, CgEO exhibits antitumor activity with lower toxicity in non-tumor cells.

5149 In-Vitro Combo Treatment of Human Liver Cancer Cell (Hep-G2) Line With Vitamin-A And RU-486

Abstract Disclosure: P. Ramaraj: None. Our previous in-vitro studies involving vitamins (vitamin-A and vitamin-D3) and steroids (progesterone and RU-486) pointed to a combination of vitamin-A and RU-486 as an efficient combo to decrease human melanoma cell growth. We extended this combo treatment to human liver cancer cell (Hep-G2) line. The aim was to check whether vit-A and RU-486 combo would also decrease human liver cancer cell line growth. Liver cancer (Hep-G2) cells were plated in a 96 well plate overnight. Following day, vit-A and RU-486 were added either alone or in different combinations for 48 hrs. After 48 hrs, cell viability and percentage of cell growth were monitored by the MTT assay. Supernatants were collected for Elisarray and quantitation of cytokine(s) by Elisa. Individual vit-A and RU-486 treatments showed a dose-dependent decrease in cell growth. Though various combinations of vit-A (50, 75, 100 μM) and RU-486 (10, 50 100 μM) also showed a decrease in cell growth, an experimentally significant decrease in cell growth was observed at vit-A 75 μM and RU-486 50 μM combination. This combo resulted in 24% cell growth compared to straight vit-A (75 μM) at 44% cell growth and RU-486 (50 μM) at 35% cell growth. Thus, this combo inhibited liver cancer cell growth also. In the future effect of this combo on normal liver cell line and the cytokine(s) if any, playing a central role in cell growth would be identified by Elisarray and quantitated by Elisa. Presentation: 6/3/2024

5149 In-vitro Combo Treatment of Human Liver Cancer cell (Hep-G2) Line with Vitamin-A and RU-486

Abstract Disclosure: P. Ramaraj: None. Our previous in-vitro studies involving vitamins (vitamin-A and vitamin-D3) and steroids (progesterone and RU-486) pointed to a combination of vitamin-A and RU-486 as an efficient combo to decrease human melanoma cell growth. We extended this combo treatment to human liver cancer cell (Hep-G2) line. The aim was to check whether vit-A and RU-486 combo would also decrease human liver cancer cell line growth. Liver cancer (Hep-G2) cells were plated in a 96 well plate overnight. Following day, vit-A and RU-486 were added either alone or in different combinations for 48 hrs. After 48 hrs, cell viability and percentage of cell growth were monitored by the MTT assay. Supernatants were collected for Elisarray and quantitation of cytokine(s) by Elisa. Individual vit-A and RU-486 treatments showed a dose-dependent decrease in cell growth. Though various combinations of vit-A (50, 75, 100 μM) and RU-486 (10, 50 100 μM) also showed a decrease in cell growth, an experimentally significant decrease in cell growth was observed at vit-A 75 μM and RU-486 50 μM combination. This combo resulted in 24% cell growth compared to straight vit-A (75 μM) at 44% cell growth and RU-486 (50 μM) at 35% cell growth. Thus, this combo inhibited liver cancer cell growth also. In the future effect of this combo on normal liver cell line and the cytokine(s) if any, playing a central role in cell growth would be identified by Elisarray and quantitated by Elisa. Presentation: 6/3/2024

IRF2 loss is associated with reduced MHC I pathway transcripts in subsets of most human cancers and causes resistance to checkpoint immunotherapy in human and mouse melanomas

BackgroundIn order for cancers to progress, they must evade elimination by CD8 T cells or other immune mechanisms. CD8 T cells recognize and kill tumor cells that display immunogenic tumor peptides bound to MHC I molecules. One of the ways that cancers can escape such killing is by reducing expression of MHC I molecules, and loss of MHC I is frequently observed in tumors. There are multiple different mechanisms that can underly the loss of MHC I complexes on tumor and it is currently unclear whether there are particular mechanisms that occur frequently and, if so, in what types of cancers. Also of importance to know is whether the loss of MHC I is reversible and how such loss and/or its restoration would impact responses to immunotherapy. Here, we investigate these issues for loss of IRF1 and IRF2, which are transcription factors that drive expression of MHC I pathway genes and some killing mechanisms.MethodsBioinformatics analyses of IRF2 and IRF2-dependent gene transcripts were performed for all human cancers in the TCGA RNAseq database. IRF2 protein-DNA-binding was analyzed in ChIPseq databases. CRISRPcas9 was used to knock out IRF1 and IRF2 genes in human and mouse melanoma cells and the resulting phenotypes were analyzed in vitro and in vivo.ResultsTranscriptomic analysis revealed that IRF2 expression was reduced in a substantial subset of cases in almost all types of human cancers. When this occurred there was a corresponding reduction in the expression of IRF2-regulated genes that were needed for CD8 T cell recognition. To test cause and effect for these IRF2 correlations and the consequences of IRF2 loss, we gene-edited IRF2 in a patient-derived melanoma and a mouse melanoma. The IRF2 gene-edited melanomas had reduced expression of transcripts for genes in the MHC I pathway and decreased levels of MHC I complexes on the cell surface. Levels of Caspase 7, an IRF2 target gene involved in CD8 T cell killing of tumors, were also reduced. This loss of IRF2 caused both human and mouse melanomas to become resistant to immunotherapy with a checkpoint inhibitor. Importantly, these effects were reversible. Stimulation of the IRF2-deficient melanomas with interferon induced the expression of a functionally homologous transcription factor, IRF1, which then restored the MHC I pathway and responsiveness to CPI.ConclusionsOur study shows that a subset of cases within most types of cancers downregulates IRF2 and that this can allow cancers to escape immune control. This can cause resistance to checkpoint blockade immunotherapy and is reversible with currently available biologics.

Retraction: mda-9/Syntenin Regulates the Metastatic Phenotype in Human Melanoma Cells by Activating Nuclear Factor-κB.

Retraction: mda-9/Syntenin Regulates the Metastatic Phenotype in Human Melanoma Cells by Activating Nuclear Factor-κB.

Vaginal Mucosal Melanoma Cell Activation in Response to Photon or Carbon Ion Irradiation

PurposePrimary gynecological melanomas are uncommon with lower survival rates compared to cutaneous melanomas. Although melanocytes have been identified in a variety of mucosal membranes, little is known about their interactions or roles inside the mucosa layer. Melanin is a common pigment in nature and is endowed with several peculiar chemical, paramagnetic, and semiconductive characteristics. One of its latest explored functions is its interaction with ionizing radiation as a protective mechanism as well as its implication in the metastatic cascade of tumor cells. Materials and MethodsIn this work, we analyzed in vitro the effects of different doses of photon and carbon ion irradiation on dendrite formation, pigmentation, migration, and invasion abilities of human mucosal melanoma cells of the vagina. We evaluated the morphology and melanin production of HMV-II cells exposed to photon and carbon ion beams with single doses between 0.5 and 10 Gy. ResultsOur results showed that irradiation induces dendrite formation or elongation and pigmentation in HMV-II cells in a dose-type-dependent and radiation-type-dependent way but also a decrease in cell motility. ConclusionThe present study describes for the first time an induction of dendritic formation, melanin production, and alterations in migration and invasion abilities by low-linear energy transfer and high-linear energy transfer radiation in human mucosal melanoma cells, suggesting a radioprotective response to further possible exposures increasing the radioresistance of these cells.

The Adsorption of Chlorpromazine on the Surface of Gold Nanoparticles and Its Effect on the Toxicity to Selected Mammalian Cells

Chlorpromazine (CPZ) is a first-generation neuroleptic with well-established antitumor and antiviral properties. Currently, numerous studies are focused on developing new methods for CPZ delivery; however, the knowledge regarding its conjugates with metal nanoparticles remains limited. The aim of this study was to prepare CPZ conjugates with gold nanoparticles (AuNPs) and evaluate their biological activity on human lymphocytes (HUT-78 and COLO 720L), as well as human (COLO 679) and murine (B16-F0) melanoma cells, in comparison to the effects induced by unconjugated CPZ molecules and AuNPs with well-defined properties. During the treatment of cells with CPZ, AuNPs, and CPZ-AuNP conjugates, changes in mitochondrial activity, membrane integrity, and the secretion of lipid peroxidation mediators were studied using standard biological assays such as MTT, LDH, and MDA assays. It was found that positively charged CPZ-AuNP conjugates more effectively reduced cell viability compared to AuNPs alone. The dose-dependent membrane damage was correlated with oxidative stress resulting from exposure to CPZ-AuNP conjugates. The activity of the conjugates depended on their composition and the size of the AuNPs. It was concluded that conjugating CPZ to AuNPs reduced its biological activity, while the cellular response to the treatment varied depending on the specific cell type.

Circular RNA-encoded oncogenic PIAS1 variant blocks immunogenic ferroptosis by modulating the balance between SUMOylation and phosphorylation of STAT1

BackgroundThe clinical response rate to immune checkpoint blockade (ICB) therapy in melanoma remains low, despite its widespread use. Circular non-coding RNAs (circRNAs) are known to play a crucial role in cancer progression and may be a key factor limiting the effectiveness of ICB treatment.MethodsThe circRNAs that were downregulated after coadministration compared with single administration of PD-1 inhibitor administration were identified through RNA-seq and Ribo-seq, and thus the circPIAS1 (mmu_circ_0015773 in mouse, has_circ_0008378 in human) with high protein coding potential was revealed. Fluorescence in situ hybridization (FISH) assays were conducted to determine the localization of circPIAS1 in human and mouse melanoma cells, as well as its presence in tumor and adjacent tissues of patients. Validation through dual-luciferase reporter assay and LC–MS/MS confirmed the ability of circPIAS1 to encode a novel 108 amino acid polypeptide (circPIAS1-108aa). Specific antisense oligonucleotides (ASOs) targeting the junction site of circPIAS1 were developed to reduce its intracellular levels. Proliferation changes in melanoma cells were assessed using CCK8, EdU, and colony formation assays. The impact of circPIAS1-108aa on the ferroptosis process of melanoma cells was studied through GSH, MDA, and C11-BODIPY staining assays. Western Blot, Immunoprecipitation (IP), and Immunoprecipitation-Mass Spectrometry (IP-MS) techniques were employed to investigate the impact of circPIAS1-108aa on the P-STAT1/SLC7A11/GPX4 signaling pathway, as well as its influence on the balance between STAT1 SUMOylation and phosphorylation. Additionally, a melanoma subcutaneous transplanted tumor mouse model was utilized to examine the combined effect of reducing circPIAS1 levels alongside PD-1 inhibitor.ResultsCompared with the group treated with PD-1 inhibitor alone, circPIAS1 was significantly down-regulated in the coadministration group and demonstrated higher protein coding potential. CircPIAS1, primarily localized in the nucleus, was notably upregulated in tumor tissues compared to adjacent tissues, where it plays a crucial role in promoting cancer cell proliferation. This circRNA can encode a unique polypeptide consisting of 108 amino acids, through which it exerts its cancer-promoting function and impedes the effectiveness of ICB therapy. Mechanistically, circPIAS1-108aa hinders STAT1 phosphorylation by recruiting SUMO E3 ligase Ranbp2 to enhance STAT1 SUMOylation, thereby reactivating the transduction of the SLC7A11/GPX4 signaling pathway and restricting the immunogenic ferroptosis induced by IFNγ. Furthermore, the combination of ASO-circPIAS1 with PD-1 inhibitor effectively inhibits melanoma growth and significantly enhances the efficacy of immune drugs in vivo.ConclusionsOur study uncovers a novel mechanism regarding immune evasion in melanoma driven by a unique 108aa peptide encoded by circPIAS1 in melanoma that dramatically hinders immunogenic ferroptosis triggered by ICB therapy via modulating the balance between SUMOylation and phosphorylation of STAT1. This work reveals circPIAS1-108aa as a critical factor limiting the immunotherapeutic effects in melanoma and propose a promising strategy for improving ICB treatment outcomes.

Black Tea Suppresses Invasiveness and Reverses TNF-α-Induced Invasiveness and Cell Stemness in Human Malignant Melanoma Cells.

Invasiveness and epithelial-mesenchymal transition (EMT) are main patterns of metastatic disease, which is the major cause cancer-related mortality in human malignant melanoma cells. Tea and its consumption extract are associated with a lower risk of several types of cancer and have anti-inflammatory and antioxidative biological effects. However, the anti-EMT and anti-cancer stemness effect of black tea ethanol extracts (BTEE) in human melanoma remain poorly understood. In this study, the effects of BTEE-reduced invasiveness, EMT, and cancer stemness were evaluated in human A 375 and A2058 melanoma cells. BTEE inhibited the activity of u-PA, migration, and invasiveness by repressing p-FAK signaling pathway. BTEE affected the EMT by downregulating the expression of β-catenin, N-cadherin, fibronectin, vimentin, and Twist-1. BTEE also reduced tumor necrosis factor-alpha (TNF-α)-induced invasiveness and cancer stemness characteristics in vitro. The growth of melanoma in nude mice xenograft model showed that BTEE suppressed A 375 tumor growth in vivo.

Novel cell spheroid culture method using Medaka dried fish powder

Highly biocompatible microcarriers are culture materials designed to enhance the efficiency of cell spheroid culture. Typically, collagen or specially processed plastic materials serve as these microcarriers. In the context of cultured-cell-based food production, however, both collagen and plastic materials present challenges regarding their cost-effectiveness and edibility. A notable issue with collagen, especially when derived from fish scales, is its low denaturation temperature, making it unsuitable for use with mammalian cells unless cross-linked. To address this issue, our research pivoted towards utilizing dried fish, a rich source of proteins including collagen. For this study, Medaka fish were selected. The fish were dried, ground into fine particles, and then impregnated with ethanol to create dried fish powder (DFP). Its efficacy was then evaluated as a microcarrier in spheroid cultures. The results revealed that DFP supports the adhesion and proliferation of various cell types, including human epidermal cells, human malignant melanoma cells, mouse fibroblasts, mouse endothelial cells and fish fibroblasts. Furthermore, Western blot analysis was used to verify the expression of mitogen-activated protein kinase-related proteins in both human epidermal cells and mouse fibroblasts cultured with DFP. This fish-derived powdered microcarrier offers a cost-effective production method requiring only a few steps. Its affordability and high performance as a carrier position it as a potentially revolutionary material for use in biological research and food production science.

Oncolytic viruses alter the biogenesis of tumor extracellular vesicles and influence their immunogenicity

Extracellular vesicles (EVs) are mediators of intercellular communication in the tumor microenvironment. Tumor EVs are commonly associated with metastasis, immunosuppression or drug resistance. Viral infections usually increase EV secretion, but little is known about the effect of oncolytic viruses (OVs) on tumor EVs. Here, we investigated the impact of oncolytic vesicular stomatitis virus (VSV) and vaccinia virus (VACV) on EVs secreted by human melanoma and thoracic cancer cells. We found that OV infection increases the production of EVs by tumor cells. These EVs contain proteins of viral origin, such as VSV-G, thus creating a continuum of particles sharing markers of both canonical EVs and viruses. As such, the presence of VSV-G on EVs improves the transfer of their protein content to cell types commonly found in the tumor microenvironment. A proteomic analysis also revealed that EVs-OV secreted during VSV infection are enriched in immunity-related proteins. Finally, CD8+ T cells incubated with EVs-OV from infected cells display slightly enhanced cytotoxic functions. Taken together, these data suggest that OVs enhance the communication mediated by tumor EVs, which could participate to the therapeutic efficacy of OVs. These results also provide rationale for engineering OVs to exploit EVs and disseminate therapeutic proteins within the tumor microenvironment.

Anti-Melanogenic Potential of Malabar Spinach (Basella alba) in Human Melanoma Cells with Oxidative Stress Suppression and Anti-Inflammatory Activities.

Basella alba has been used in Thai remedies to treat skin disorders, but scientific evidence supporting its efficacy is currently limited. In this study, we investigated the inhibitory effects of B. alba extracts on melanin production using melanoma cells, as well as their impact on oxidative stress and inflammation in keratinocytes. The results demonstrate that B. alba extracts inhibited melanin content and cellular tyrosinase activity in 3-isobutyl-1-methylxanthine (IBMX)-induced melanoma cells by downregulating MITF and the pigmentary genes TYR, TRP-1, and DCT. Interestingly, the MITF regulator gene was inhibited by both the 50% and 95% ethanolic extracts of B. alba with levels of 0.97 ± 0.19 and 0.92 ± 0.09 of the control, respectively, which are comparable to those observed in the arbutin treatment group at 0.84 ± 0.05 of the control. Moreover, after hydrogen peroxide (H2O2) exposure, pretreatment with B. alba reduced lipid peroxidation byproducts and increased the levels of antioxidant-related genes, including SOD-1, GPX-1, and NRF2. Notably, the suppression of the POMC promoter gene in keratinocytes was observed, which may disrupt melanogenesis in melanocytes involving the MC1R signaling pathway. MC1R mRNA expression decreased in the treatments with 50% and 95% ethanolic extracts of B. alba, with relative levels of 0.97 ± 0.18 and 0.90 ± 0.10 of the control, respectively, similar to the arbutin-treated group (0.88 ± 0.25 of control). A significant reduction in nitric oxide was also observed in the B. alba-treated groups, along with a decrease in genes associated with pro-inflammatory cytokines, including IL-1β, IL-6, and COX-2. These findings suggest that B. alba has potential in the prevention of skin-related problems.

Leveraging gene correlations in single cell transcriptomic data

BackgroundMany approaches have been developed to overcome technical noise in single cell RNA-sequencing (scRNAseq). As researchers dig deeper into data—looking for rare cell types, subtleties of cell states, and details of gene regulatory networks—there is a growing need for algorithms with controllable accuracy and fewer ad hoc parameters and thresholds. Impeding this goal is the fact that an appropriate null distribution for scRNAseq cannot simply be extracted from data in which ground truth about biological variation is unknown (i.e., usually).ResultsWe approach this problem analytically, assuming that scRNAseq data reflect only cell heterogeneity (what we seek to characterize), transcriptional noise (temporal fluctuations randomly distributed across cells), and sampling error (i.e., Poisson noise). We analyze scRNAseq data without normalization—a step that skews distributions, particularly for sparse data—and calculate p values associated with key statistics. We develop an improved method for selecting features for cell clustering and identifying gene–gene correlations, both positive and negative. Using simulated data, we show that this method, which we call BigSur (Basic Informatics and Gene Statistics from Unnormalized Reads), captures even weak yet significant correlation structures in scRNAseq data. Applying BigSur to data from a clonal human melanoma cell line, we identify thousands of correlations that, when clustered without supervision into gene communities, align with known cellular components and biological processes, and highlight potentially novel cell biological relationships.ConclusionsNew insights into functionally relevant gene regulatory networks can be obtained using a statistically grounded approach to the identification of gene–gene correlations.