RESUMEN

Epigenetic modifications to DNA and chromatin control oncogenic and tumor-suppressive mechanisms in melanoma. Ezh2, the catalytic component of the Polycomb Repressive Complex 2 (PRC2), which mediates methylation of lysine 27 on histone 3 (H3K27me3), can regulate both melanoma initiation and progression. We previously found that mutant Ezh2Y641F interacts with the immune regulator Stat3 and together they affect anti-tumor immunity. However, given the numerous downstream targets and pathways affected by Ezh2, many mechanisms that determine its oncogenic activity remain largely unexplored. Using genetically engineered mouse models, we further investigated the role of pathways downstream of Ezh2 in melanoma carcinogenesis and identified significant enrichment in several autophagy signatures, along with increased expression of autophagy regulators, such as Atg7. In this study, we investigated the effect of Atg7 on melanoma growth and tumor immunity within the context of a wild-type or Ezh2Y641F epigenetic state. We found that the Atg7 locus is controlled by multiple Ezh2 and Stat3 binding sites, Atg7 expression is dependent on Stat3 expression, and that deletion of Atg7 slows down melanoma cell growth in vivo, but not in vitro. Atg7 deletion also results in increased CD8 + T cells in Ezh2Y641F melanomas and reduced myelosuppressive cell infiltration in the tumor microenvironment, particularly in Ezh2WT melanomas, suggesting a strong immune system contribution in the role of Atg7 in melanoma progression. These findings highlight the complex interplay between genetic mutations, epigenetic regulators, and autophagy in shaping tumor immunity in melanoma.

Asunto(s)

Proteína 7 Relacionada con la Autofagia , Proteína Potenciadora del Homólogo Zeste 2 , Factor de Transcripción STAT3 , Animales , Factor de Transcripción STAT3/metabolismo , Ratones , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Proteína Potenciadora del Homólogo Zeste 2/genética , Proteína 7 Relacionada con la Autofagia/genética , Proteína 7 Relacionada con la Autofagia/metabolismo , Melanoma Experimental/inmunología , Melanoma Experimental/patología , Melanoma Experimental/genética , Melanoma Experimental/metabolismo , Microambiente Tumoral/inmunología , Ratones Endogámicos C57BL , Regulación Neoplásica de la Expresión Génica , Melanoma/inmunología , Melanoma/metabolismo , Melanoma/genética , Melanoma/patología , Epigénesis Genética , Línea Celular Tumoral , Humanos , Autofagia/inmunología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo

RESUMEN

Melanosomes are specialized membrane-bound organelles where melanin is synthesized and stored. The levels of melanin can be effectively reduced by inhibiting melanin synthesis or promoting melanosome degradation via autophagy. Ceramide, a key component in the metabolism of sphingolipids, is crucial for preserving the skin barrier, keeping it hydrated, and warding off the signs of aging. Our preliminary study indicated that a long-chain C22-ceramide compound (Ehux-C22) isolated from the marine microalga Emiliania huxleyi, reduced melanin levels via melanosomal autophagy in B16 cells. Recently, microRNAs (miRNAs) were shown to act as melanogenesis-regulating molecules in melanocytes. However, whether the ceramide Ehux-C22 can induce melanosome autophagy at the post-transcriptional level, and which potential autophagy-dependent mechanisms are involved, remains unknown. Here, miR-199a-3p was screened and identified as a novel upregulated miRNA in Ehux-C22-treated B16 cells. An in vitro high melanin expression model in cultured mouse melanoma cells (B16 cells) was established by using 0.2 µM alpha-melanocyte-stimulating hormone(α-MSH) and used for subsequent analyses. miR-199a-3p overexpression significantly enhanced melanin degradation, as indicated by a reduction in the melanin level and an increase in melanosome autophagy. Further investigation demonstrated that in B16 cells, Ehux-C22 activated miR-199a-3p and inhibited mammalian target of rapamycin(mTOR) level, thus activating the mTOR-ULK1 signaling pathway by promoting the expression of unc-51-like autophagy activating kinase 1 (ULK1), B-cell lymphoma-2 (Bcl-2), Beclin-1, autophagy-related gene 5 (ATG5), and microtubule-associated protein light chain 3 (LC3-II) and degrading p62. Therefore, the roles of Ehux-C22-regulated miR-199a-3p and the mTOR pathway in melanosomal autophagy were elucidated. This research may provide novel perspectives on the post-translational regulation of melanin metabolism, which involves the coordinated control of melanosomes.

Asunto(s)

Autofagia , Ceramidas , Melaninas , Melanoma Experimental , Melanosomas , MicroARNs , Transducción de Señal , Serina-Treonina Quinasas TOR , MicroARNs/genética , MicroARNs/metabolismo , Animales , Ratones , Serina-Treonina Quinasas TOR/metabolismo , Melanosomas/metabolismo , Ceramidas/metabolismo , Melaninas/metabolismo , Melaninas/biosíntesis , Melanoma Experimental/metabolismo , Melanoma Experimental/patología , Melanoma Experimental/genética , Línea Celular Tumoral , alfa-MSH/metabolismo , Melanocitos/metabolismo , Melanocitos/efectos de los fármacos

RESUMEN

Tumour-host immune interactions lead to complex changes in the tumour microenvironment (TME), impacting progression, metastasis and response to therapy. While it is clear that cancer cells can have the capacity to alter immune landscapes, our understanding of this process is incomplete. Herein we show that endocytic trafficking at the plasma membrane, mediated by the small GTPase ARF6, enables melanoma cells to impose an immunosuppressive TME that accelerates tumour development. This ARF6-dependent TME is vulnerable to immune checkpoint blockade therapy (ICB) but in murine melanoma, loss of Arf6 causes resistance to ICB. Likewise, downregulation of ARF6 in patient tumours correlates with inferior overall survival after ICB. Mechanistically, these phenotypes are at least partially explained by ARF6-dependent recycling, which controls plasma membrane density of the interferon-gamma receptor. Collectively, our findings reveal the importance of endomembrane trafficking in outfitting tumour cells with the ability to shape their immune microenvironment and respond to immunotherapy.

Asunto(s)

Factor 6 de Ribosilación del ADP , Factores de Ribosilacion-ADP , Membrana Celular , Inhibidores de Puntos de Control Inmunológico , Melanoma , Microambiente Tumoral , Microambiente Tumoral/inmunología , Animales , Humanos , Ratones , Factores de Ribosilacion-ADP/metabolismo , Factores de Ribosilacion-ADP/genética , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Melanoma/genética , Melanoma/tratamiento farmacológico , Melanoma/metabolismo , Melanoma/patología , Melanoma/inmunología , Línea Celular Tumoral , Membrana Celular/metabolismo , Receptor de Interferón gamma , Receptores de Interferón/metabolismo , Receptores de Interferón/genética , Transporte de Proteínas , Melanoma Experimental/inmunología , Melanoma Experimental/metabolismo , Melanoma Experimental/patología , Melanoma Experimental/genética , Ratones Endogámicos C57BL , Femenino

RESUMEN

BACKGROUND: In addition to their fundamental roles in preserving vascular integrity, platelets also contribute to tumor angiogenesis and metastasis. However, despite being a reservoir for angiogenic and metastatic cytokines, platelets also harbor negative regulators of tumor progression. Angpt1 (angiopoietin-1) is a cytokine essential for developmental angiogenesis that also protects against tumor cell metastasis through an undefined mechanism. Although activated platelets release Angpt1 from α-granules into circulation, the contributions of platelet Angpt1 to tumor growth, angiogenesis, and metastasis have not been investigated. METHODS: Using cytokine arrays and ELISAs, we first compared platelet Angpt1 levels in breast and melanoma mouse tumor models to tumor-free controls. We then assessed tumor growth and metastasis in mice lacking megakaryocyte and platelet Angpt1 (Angpt1Plt KO). The spontaneous metastasis of mammary-injected tumor cells to the lungs was quantified using RT-PCR (reverse transcription-polymerase chain reaction). The lung colonization of intravenously injected tumor cells and tumor cell extravasation were determined using fluorescent microscopy and flow cytometry. RESULTS: Platelet Angpt1 is selectively upregulated in the PyMT (polyoma middle tumor antigen) breast cancer mouse model, and platelets are the principal source of Angpt1 in blood circulation. While primary tumor growth and angiogenesis were unaffected, Angpt1Plt KO mice had both increased spontaneous lung metastasis and tumor cell lung colonization following mammary or intravenous injection, respectively. Although platelet Angpt1 did not affect initial tumor cell entrapment in the lungs, Angpt1Plt KO mice had increased tumor cell retention and extravasation. Serum from Angpt1Plt KO mice increased endothelial permeability and reduced VE (vascular endothelial)-cadherin expression at endothelial junctions compared with serum from control mice (Angpt1WT). CONCLUSIONS: Platelets provide an intravascular source of Angpt1 that restrains tumor metastasis by preserving the lung microvasculature to limit tumor cell extravasation.

Asunto(s)

Angiopoyetina 1 , Plaquetas , Neoplasias Pulmonares , Ratones Noqueados , Neovascularización Patológica , Animales , Angiopoyetina 1/genética , Angiopoyetina 1/metabolismo , Angiopoyetina 1/sangre , Plaquetas/metabolismo , Plaquetas/patología , Femenino , Neoplasias Pulmonares/secundario , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/sangre , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/prevención & control , Ratones Endogámicos C57BL , Melanoma Experimental/patología , Melanoma Experimental/metabolismo , Melanoma Experimental/irrigación sanguínea , Melanoma Experimental/sangre , Melanoma Experimental/secundario , Melanoma Experimental/genética , Línea Celular Tumoral , Ratones , Neoplasias Mamarias Experimentales/patología , Neoplasias Mamarias Experimentales/genética , Neoplasias Mamarias Experimentales/metabolismo , Neoplasias Mamarias Experimentales/sangre , Carga Tumoral , Modelos Animales de Enfermedad

RESUMEN

The effects of the enzyme N-acetylgalactosamine-4-sulfatase (Arylsulfatase B, ARSB), which removes the 4-sulfate group at the non-reducing end of chondroitin 4-sulfate, on the expression of PD-L1 were determined, and the underlying mechanism of PD-L1 expression was elucidated. Initial experiments in human melanoma cells (A375) showed that PD-L1 expression increased from 357 ± 31 to 796 ± 50 pg/mg protein (p < 10-11) when ARSB was silenced in A375 cells. In subcutaneous B16F10 murine melanomas, PD-L1 declined from 1227 ± 189 to 583 ± 110 pg/mg protein (p = 1.67 × 10-7), a decline of 52%, following treatment with exogenous, bioactive recombinant ARSB. This decline occurred in association with reduced tumor growth and prolongation of survival, as previously reported. The mechanism of regulation of PD-L1 expression by ARSB is attributed to ARSB-mediated alteration in chondroitin 4-sulfation, leading to changes in free galectin-3, c-Jun nuclear localization, HDAC3 expression, and effects of acetyl-H3 on the PD-L1 promoter. These findings indicate that changes in ARSB contribute to the expression of PD-L1 in melanoma and can thereby affect the immune checkpoint response. Exogenous ARSB acted on melanoma cells and normal melanocytes through the IGF2 receptor. The decline in PD-L1 expression by exogenous ARSB may contribute to the impact of ARSB on melanoma progression.

Asunto(s)

Antígeno B7-H1 , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Histona Desacetilasas , Melanoma Experimental , Melanoma , N-Acetilgalactosamina-4-Sulfatasa , Animales , Humanos , Ratones , N-Acetilgalactosamina-4-Sulfatasa/metabolismo , N-Acetilgalactosamina-4-Sulfatasa/genética , Antígeno B7-H1/metabolismo , Antígeno B7-H1/genética , Histona Desacetilasas/metabolismo , Histona Desacetilasas/genética , Línea Celular Tumoral , Melanoma Experimental/metabolismo , Melanoma Experimental/patología , Melanoma Experimental/genética , Melanoma/metabolismo , Melanoma/genética , Melanoma/patología , Galectina 3/metabolismo , Galectina 3/genética , Regiones Promotoras Genéticas , Proteínas Sanguíneas , Galectinas

RESUMEN

Secreted protein acidic and cysteine rich/osteonectin, cwcv and kazal-like domain proteoglycan 2 (SPOCK2) is a protein that regulates cell differentiation and growth. Recent studies have reported that SPOCK2 plays important roles in the progression of various human cancers; however, the role of SPOCK2 in melanoma remains unknown. Therefore, this study investigated the roles of SPOCK2 and the related mechanisms in melanoma progression. To evaluate the clinical significance of SPOCK2 expression in patients with melanoma, we analysed the association between SPOCK2 expression and its prognostic value for patients with melanoma using systematic multiomic analysis. Subsequently, to investigate the roles of Spock2 in melanoma progression in vitro and in vivo, we knocked down Spock2 in the B16F10 melanoma cell line. High SPOCK2 levels were positively associated with good prognosis and long survival rate of patients with melanoma. Spock2 knockdown promoted melanoma cell proliferation by inducing the cell cycle and inhibiting apoptosis. Moreover, Spock2 downregulation significantly increased cell migration and invasion by upregulating MMP2 and MT1-MMP. The increased cell proliferation and migration were inhibited by MAPK inhibitor, and ERK phosphorylation was considerably enhanced in Spock2 knockdown cells. Therefore, Spock2 could function as a tumour suppressor gene to regulate melanoma progression by regulating the MAPK/ERK signalling pathway. Additionally, Spock2 knockdown cell injection induced considerable tumour growth and lung metastasis in C57BL6 mice compared to that in the control group. Our findings suggest that SPOCK2 plays crucial roles in malignant progression of melanoma and functions as a novel therapeutic target of melanoma.

Asunto(s)

Apoptosis , Movimiento Celular , Proliferación Celular , Progresión de la Enfermedad , Melanoma , Neoplasias Cutáneas , Animales , Femenino , Humanos , Masculino , Ratones , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/genética , Ciclo Celular , Línea Celular Tumoral , Técnicas de Silenciamiento del Gen , Sistema de Señalización de MAP Quinasas , Metaloproteinasa 14 de la Matriz/metabolismo , Metaloproteinasa 14 de la Matriz/genética , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/genética , Melanoma/genética , Melanoma/patología , Melanoma/metabolismo , Melanoma Experimental/genética , Melanoma Experimental/patología , Melanoma Experimental/metabolismo , Ratones Endogámicos C57BL , Invasividad Neoplásica , Pronóstico , Proteoglicanos/metabolismo , Proteoglicanos/genética , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo

RESUMEN

Dendritic cells (DCs) are the main antigen presenting cells of the immune system and are essential for anti-tumor responses. DC-based immunotherapies are used in cancer treatment, but their functionality is not optimized and their clinical efficacy is currently limited. Approaches to improve DC functionality in anti-tumor immunity are therefore required. We have previously shown that the loss of ß2-integrin-mediated adhesion leads to epigenetic reprogramming of bone marrow-derived DCs (BM-DCs), resulting in an increased expression of costimulatory markers (CD86, CD80, and CD40), cytokines (IL-12) and the chemokine receptor CCR7. We now show that the loss of ß2-integrin-mediated adhesion of BM-DCs also leads to a generally suppressed metabolic profile, with reduced metabolic rate, decreased ROS production, and lowered glucose uptake in cells. The mRNA levels of glycolytic enzymes and glucose transporters were reduced, indicating transcriptional regulation of the metabolic phenotype. Surprisingly, although signaling through a central regulator of immune cell metabolisms, the mechanistic target of rapamycin (mTOR), was increased in BM-DCs with dysfunctional integrins, rapamycin treatment revealed that mTOR signaling was not involved in suppressing DC metabolism. Instead, bioinformatics and functional analyses showed that the Ikaros transcription factor may be involved in regulating the metabolic profile of non-adhesive DCs. Inversely, we found that induction of metabolic stress through treatment of cells with low levels of an inhibitor of glycolysis, 2-deoxyglucose (2DG), led to increased BM-DC activation. Specifically, 2DG treatment led to increased levels of Il-12 and Ccr7 mRNA, increased production of IL-12, increased levels of cell surface CCR7 and increased in vitro migration and T cell activation potential. Furthermore, 2DG treatment led to increased histone methylation in cells (H3K4me3, H3K27me3), indicating metabolic reprogramming. Finally, metabolic stress induced by 2DG treatment led to improved BM-DC-mediated anti-tumor responses in vivo in a melanoma cancer model, B16-OVA. In conclusion, our results indicate a role for ß2-integrin-mediated adhesion in regulating a novel type of metabolic reprogramming of DCs and DC-mediated anti-tumor responses, which may be targeted to enhance DC-mediated anti-tumor responses in cancer immunotherapy.

Asunto(s)

Antígenos CD18 , Células Dendríticas , Células Dendríticas/metabolismo , Células Dendríticas/inmunología , Animales , Ratones , Antígenos CD18/metabolismo , Antígenos CD18/genética , Ratones Endogámicos C57BL , Adhesión Celular , Receptores CCR7/metabolismo , Receptores CCR7/genética , Melanoma Experimental/patología , Melanoma Experimental/inmunología , Melanoma Experimental/metabolismo , Melanoma Experimental/genética , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Humanos , Reprogramación Metabólica

RESUMEN

BACKGROUND: Circulating cancer cells have characteristics of tumor self-targeting. Modified circulating tumor cells may serve as tumor-targeted cellular drugs. Tremella fuciformis-derived polysaccharide (TFP) is related to immune regulation and tumor inhibition, so could B16 cells reeducated by TFP be an effective anti-tumor drug? OBJECTIVES: To evaluate the intrinsic therapeutic potential of B16 cells exposed to TFP and clarify the therapeutic molecules or pathways altered by this process. MATERIAL AND METHODS: RNA-seq technology was used to study the effect of TFP-reeducated B16 cells on the immune and inflammatory system by placing the allograft subcutaneously in C57BL/6 mice. RESULTS: Tremella fuciformis-derived polysaccharide-reeducated B16 cells recruited leukocytes, neutrophils, dendritic cells (DCs), and mast cells into the subcutaneous region and promoted the infiltration of several cytokines such as tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 1ß (IL-1ß), and interleukin 1 (IL-1). Tumor necrosis factor alpha also activated Th17 lymphocytes to secrete interleukin 17 (IL-17) and interferon gamma (IFN-γ). The co-expression of IFN-γ and IL-17 was favorable for tumor immunity to shrink tumors. In short, TFP-reeducated B16 cells activated the innate and adaptive immune responses, especially Th17 cell differentiation and IFN-γ production, as well as the TNF-α signaling pathway, which re-regulated the inflammatory and immune systems. CONCLUSION: B16 cells subcutaneously exposed to TFP in mice induced an immune and inflammatory response to inhibit tumors. The study of the function of TFP-reeducated B16 cells to improve cancer immunotherapy may be of particular research interest. This approach could be an alternative and more efficient strategy to deliver cytokines and open up new possibilities for long-lasting, multi-level tumor control.

Asunto(s)

Melanoma Experimental , Ratones Endogámicos C57BL , Animales , Melanoma Experimental/inmunología , Melanoma Experimental/genética , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/metabolismo , Ratones , Perfilación de la Expresión Génica/métodos , Citocinas/metabolismo , Basidiomycota/química , Línea Celular Tumoral , Polisacáridos/farmacología , Polisacáridos Fúngicos/farmacología , Inflamación/inmunología

RESUMEN

Solid tumors generally exhibit chromosome copy number variation, which is typically caused by chromosomal instability (CIN) in mitosis. The resulting aneuploidy can drive evolution and associates with poor prognosis in various cancer types as well as poor response to T-cell checkpoint blockade in melanoma. Macrophages and the SIRPα-CD47 checkpoint are understudied in such contexts. Here, CIN is induced in poorly immunogenic B16F10 mouse melanoma cells using spindle assembly checkpoint MPS1 inhibitors that generate persistent micronuclei and diverse aneuploidy while skewing macrophages toward a tumoricidal 'M1-like' phenotype based on markers and short-term anti-tumor studies. Mice bearing CIN-afflicted tumors with wild-type CD47 levels succumb similar to controls, but long-term survival is maximized by SIRPα blockade on adoptively transferred myeloid cells plus anti-tumor monoclonal IgG. Such cells are the initiating effector cells, and survivors make de novo anti-cancer IgG that not only promote phagocytosis of CD47-null cells but also suppress tumor growth. CIN does not affect the IgG response, but pairing CIN with maximal macrophage anti-cancer activity increases durable cures that possess a vaccination-like response against recurrence.

Asunto(s)

Inestabilidad Cromosómica , Inmunoglobulina G , Macrófagos , Animales , Ratones , Macrófagos/inmunología , Antígeno CD47/metabolismo , Antígeno CD47/genética , Antígeno CD47/inmunología , Ratones Endogámicos C57BL , Melanoma Experimental/inmunología , Melanoma Experimental/terapia , Melanoma Experimental/genética , Línea Celular Tumoral , Femenino

RESUMEN

Malignant melanoma (MM) is a malignant tumor associated with high mortality rates and propensity for metastasis. Despite advancement in treatment, the incidence of MM continue to rise globally. GPR168, also known as MrgprF, is a MAS related GPR family member. The low expression of GPR168 has also been reported in many malignant tumors including MM. In the study, the statistical analysis from The Cancer Genome Atlas (TCGA) revealed a significant down regulation of GPR168 in melanoma compared to normal melanocytes, underscoring its importance in MM. The aim of the present study is to investigate the affect of GPR168 overexpression and elucidate its molecular mechanisms in MM cells. In addition, we used mouse melanoma B16-F10 cell line and xenograph tumor model to explore the function of GPR168 in melanoma. Our findings demonstrate that GPR168 overexpression could inhibit B16-F10 cell proliferation, migration, and xenografts tumor growth. Further, mechanistic studies revealed that GPR168 affected B16-F10 progress through Akt signal pathway with the decreased expression of p-Akt, p-GSK-3ß, ß-catenin, Myc, CyclinD1 and CDK4. In order to validate these findings, a rescue experiment was formulated employing GPR168 polyclonal antibody (Anti-GPR168 pAbs) to block GPR168 functionality. The addition of Anti-GPR168 pAbs into the culture medium restored both cell proliferation and migration. In conclusion, the overexpression of GPR168 in mouse melanoma B16-F10 cells suppressed proliferation and migration through the Akt signaling pathway. These findings collectively propose GPR168 as a promising novel tumor suppressor in MM, suggesting its potential as a therapeutic target in future interventions.

Asunto(s)

Proliferación Celular , Melanoma Experimental , Proteínas Proto-Oncogénicas c-akt , Receptores Acoplados a Proteínas G , Transducción de Señal , Animales , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratones , Melanoma Experimental/patología , Melanoma Experimental/metabolismo , Melanoma Experimental/genética , Línea Celular Tumoral , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética , Movimiento Celular , Humanos , Regulación Neoplásica de la Expresión Génica , Ratones Endogámicos C57BL

RESUMEN

It is widely postulated that the majority of pathologically elevated extracellular or cell-free DNA (cfDNA) in cancer originates from tumor cells; however, evidence has emerged regarding the significant contributions of other cells from the tumor microenvironment. Here, the effect of cfDNA originating from murine B16 melanoma cells and L929 fibroblasts on B16 cells was investigated. It was found that cfDNAL929 increased the viability and migration properties of B16 cells in vitro and their invasiveness in vivo. In contrast, cfDNAB16 exhibited a negative effect on B16 cells, reducing their viability and migration in vitro, which in vivo led to decreased tumor size and metastasis number. It was shown that cell treatment with both cfDNAs resulted in an increase in the expression of genes encoding DNases and the oncogenes Braf, Kras, and Myc. cfDNAL929-treated cells were shown to experience oxidative stress. Gene expression changes in the case of cfDNAB16 treatment are well correlated with the observed decrease in proliferation and migration of B16 cells. The obtained data may indicate the possible involvement of fibroblast DNA in the tumor microenvironment in tumor progression and, potentially, in the formation of new tumor foci due to the transformation of normal cells.

Asunto(s)

Movimiento Celular , Ácidos Nucleicos Libres de Células , Fibroblastos , Melanoma Experimental , Microambiente Tumoral , Animales , Ratones , Fibroblastos/metabolismo , Melanoma Experimental/patología , Melanoma Experimental/metabolismo , Melanoma Experimental/genética , Microambiente Tumoral/genética , Ácidos Nucleicos Libres de Células/genética , Línea Celular Tumoral , Proliferación Celular , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , ADN de Neoplasias/metabolismo , ADN de Neoplasias/genética , Supervivencia Celular/efectos de los fármacos , Estrés Oxidativo

RESUMEN

The immunoglobulin superfamily (IgSF) is one of the largest families of cell-surface molecules involved in various cell-cell interactions, including cancer-stromal interactions. In this study, we undertook a comprehensive RT-PCR-based screening for IgSF molecules that promote experimental lung metastasis in mice. By comparing the expression of 325 genes encoding cell-surface IgSF molecules between mouse melanoma B16 cells and its highly metastatic subline, B16F10 cells, we found that expression of the immunoglobulin superfamily member 3 gene (Igsf3) was significantly enhanced in B16F10 cells than in B16 cells. Knockdown of Igsf3 in B16F10 cells significantly reduced lung metastasis following intravenous injection into C57BL/6 mice. IGSF3 promoted adhesion of B16F10 cells to vascular endothelial cells and functioned as a homophilic cell adhesion molecule between B16F10 cells and vascular endothelial cells. Notably, the knockdown of IGSF3 in either B16F10 cells or vascular endothelial cells suppressed the transendothelial migration of B16F10 cells. Moreover, IGSF3 knockdown suppressed the extravasation of B16F10 cells into the lungs after intravenous injection. These results suggest that IGSF3 promotes the metastatic potential of B16F10 cells in the lungs by facilitating their adhesion to vascular endothelial cells.

Asunto(s)

Endotelio Vascular , Neoplasias Pulmonares , Melanoma Experimental , Animales , Humanos , Ratones , Adhesión Celular , Moléculas de Adhesión Celular/metabolismo , Moléculas de Adhesión Celular/genética , Línea Celular Tumoral , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Técnicas de Silenciamiento del Gen , Inmunoglobulinas/metabolismo , Inmunoglobulinas/genética , Neoplasias Pulmonares/secundario , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Melanoma Experimental/patología , Melanoma Experimental/metabolismo , Melanoma Experimental/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Ratones Endogámicos C57BL

RESUMEN

T cell immunity is critical for human defensive immune response. Exploring the key molecules during the process provides new targets for T cell-based immunotherapies. CMC1 is a mitochondrial electron transport chain (ETC) complex IV chaperon protein. By establishing in-vitro cell culture system and Cmc1 gene knock out mice, we evaluated the role of CMC1 in T cell activation and differentiation. The B16-OVA tumor model was used to test the possibility of targeting CMC1 for improving T cell anti-tumor immunity. We identified CMC1 as a positive regulator in CD8+T cells activation and terminal differentiation. Meanwhile, we found that CMC1 increasingly expressed in exhausted T (Tex) cells. Genetic lost of Cmc1 inhibits the development of CD8+T cell exhaustion in mice. Instead, deletion of Cmc1 in T cells prompts cells to differentiate into metabolically and functionally quiescent cells with increased memory-like features and tolerance to cell death upon repetitive or prolonged T cell receptor (TCR) stimulation. Further, the in-vitro mechanistic study revealed that environmental lactate enhances CMC1 expression by inducing USP7, mediated stabilization and de-ubiquitination of CMC1 protein, in which a mechanism we propose here that the lactate-enriched tumor microenvironment (TME) drives CD8+TILs dysfunction through CMC1 regulatory effects on T cells. Taken together, our study unraveled the novel role of CMC1 as a T cell regulator and its possibility to be utilized for anti-tumor immunotherapy.

Asunto(s)

Linfocitos T CD8-positivos , Ratones Noqueados , Proteínas Mitocondriales , Animales , Ratones , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Diferenciación Celular/inmunología , Activación de Linfocitos/inmunología , Melanoma Experimental/inmunología , Melanoma Experimental/patología , Melanoma Experimental/genética , Ratones Endogámicos C57BL , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Ubiquitina Tiolesterasa/metabolismo , Ubiquitina Tiolesterasa/genética

RESUMEN

Cytotoxic CD8+ T cells are central to the antitumor immune response by releasing cytotoxic granules that kill tumor cells. They are activated by antigen-presenting cells, which become activated by DAMPs (damage associated molecular patterns) through MyD88. However, the suppressive tumor microenvironment promotes T-cell tolerance to tumor antigens, in part by enhancing the activity of immune checkpoint molecules that prevent CD8+ T-cell activation and cytotoxicity. MyD88 limits CD4+ T-cell activation during cardiac adaptation to stress. A similar mechanism is hypothesized to exist in CD8+ T cells that could be modulated to improve antitumor immunity. Herein, adoptive transfer of MyD88-/- CD8+ T cells in melanoma-bearing T-cell-deficient mice resulted in slower tumor growth, greater intratumoral T-cell accumulation, and higher melanoma cell death compared with transfer of wild-type CD8+ T cells. These findings were also observed in T-cell-specific MyD88-/- mice compared with wild-type littermates implanted with melanoma. Mechanistically, deletion of MyD88 enhanced CD8+ T-cell activation and survival, and T-cell receptor induced degranulation of cytotoxic molecules, overall improving the killing of melanoma cells. This enhanced cytotoxicity was retained in mice bearing tumors expressing the specific antigen for which cytotoxic T-cells were restricted. This study's results demonstrate a conserved mechanism for MyD88 in modulating CD8+ T-cell activation and represent a novel target in improving cancer immunotherapy.

Asunto(s)

Linfocitos T CD8-positivos , Factor 88 de Diferenciación Mieloide , Animales , Ratones , Linfocitos T CD8-positivos/inmunología , Activación de Linfocitos/inmunología , Melanoma/inmunología , Melanoma/patología , Melanoma/genética , Melanoma/terapia , Melanoma Experimental/inmunología , Melanoma Experimental/patología , Melanoma Experimental/terapia , Melanoma Experimental/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Factor 88 de Diferenciación Mieloide/genética , Factor 88 de Diferenciación Mieloide/metabolismo , Microambiente Tumoral/inmunología

RESUMEN

Tight junction (TJ) proteins (Tjps), Tjp1 and Tjp2, are tight junction-associated scaffold proteins that bind to the transmembrane proteins of tight junctions and the underlying cytoskeleton. In this study, we first analyzed the tumorigenic characteristics of B16-F10 melanoma cells, including cell proliferation, migration, invasion, metastatic potential, and the expression patterns of related proteins, after the CRISPR-Cas9-mediated knockout (KO) of Tjp genes. The proliferation of Tjp1 and Tjp2 KO cells significantly increased in vitro. Other tumorigenic characteristics, including migration and invasion, were significantly enhanced in Tjp1 and Tjp2 KO cells. Zonula occludens (ZO)-associated protein Claudin-1 (CLDN-1), which is a major component of tight junctions and functions in controlling cell-to-cell adhesion, was decreased in Tjp KO cells. Additionally, Tjp KO significantly stimulated tumor growth and metastasis in an in vivo mouse model. We performed a transcriptome analysis using next-generation sequencing (NGS) to elucidate the key genes involved in the mechanisms of action of Tjp1 and Tjp2. Among the various genes affected by Tjp KO-, cell cycle-, cell migration-, angiogenesis-, and cell-cell adhesion-related genes were significantly altered. In particular, we found that the Ninjurin-1 (Ninj1) and Catenin alpha-1 (Ctnna1) genes, which are known to play fundamental roles in Tjps, were significantly downregulated in Tjp KO cells. In summary, tumorigenic characteristics, including cell proliferation, migration, invasion, tumor growth, and metastatic potential, were significantly increased in Tjp1 and Tjp2 KO cells, and the knockout of Tjp genes significantly affected the expression of related proteins.

Asunto(s)

Melanoma Experimental , Uniones Estrechas , Animales , Ratones , Carcinogénesis/genética , Proliferación Celular , Proteínas de Uniones Estrechas/genética , Melanoma Experimental/genética , Factores de Crecimiento Nervioso , Moléculas de Adhesión Celular Neuronal

RESUMEN

Metastasis is the leading cause of mortality in cancer patients. L-type amino acid transporter 1 (LAT1, SLC7A5) is a Na+-independent neutral amino acid transporter highly expressed in various cancers to support their growth. Although high LAT1 expression is closely associated with cancer metastasis, its role in this process remains unclear. This study aimed to investigate the effect of LAT1 inhibition on cancer metastasis using B16-F10 melanoma mouse models. Our results demonstrated that nanvuranlat (JPH203), a high-affinity LAT1-selective inhibitor, suppressed B16-F10 cell proliferation, migration, and invasion. Similarly, LAT1 knockdown reduced cell proliferation, migration, and invasion. LAT1 inhibitors and LAT1 knockdown diminished B16-F10 lung metastasis in a lung metastasis model. Furthermore, nanvuranlat and LAT1 knockdown suppressed lung, spleen, and lymph node metastasis in an orthotopic metastasis model. We discovered that the LAT1 inhibitor reduced the cell surface expression of integrin αvß3. Our findings revealed that the downregulation of the mTOR signaling pathway, induced by LAT1 inhibitors, decreased the expression of integrin αvß3, contributing to the suppression of metastasis. These results highlight the critical role of LAT1 in cancer metastasis and suggest that LAT1 inhibition may serve as a potential target for anti-metastasis cancer therapy.

Asunto(s)

Neoplasias Pulmonares , Melanoma Experimental , Neoplasias Primarias Secundarias , Animales , Ratones , Sistemas de Transporte de Aminoácidos , Modelos Animales de Enfermedad , Integrina alfaVbeta3 , Transportador de Aminoácidos Neutros Grandes 1/genética , Neoplasias Pulmonares/genética , Melanoma Experimental/genética

RESUMEN

Aggressive tumors evade cytotoxic T lymphocytes by suppressing MHC class-I (MHC-I) expression that also compromises tumor responsiveness to immunotherapy. MHC-I defects strongly correlate to defective expression of NLRC5, the transcriptional activator of MHC-I and antigen processing genes. In poorly immunogenic B16 melanoma cells, restoring NLRC5 expression induces MHC-I and elicits antitumor immunity, raising the possibility of using NLRC5 for tumor immunotherapy. As the clinical application of NLRC5 is constrained by its large size, we examined whether a smaller NLRC5-CIITA fusion protein, dubbed NLRC5-superactivator (NLRC5-SA) as it retains the ability to induce MHC-I, could be used for tumor growth control. We show that stable NLRC5-SA expression in mouse and human cancer cells upregulates MHC-I expression. B16 melanoma and EL4 lymphoma tumors expressing NLRC5-SA are controlled as efficiently as those expressing full-length NLRC5 (NLRC5-FL). Comparison of MHC-I-associated peptides (MAPs) eluted from EL4 cells expressing NLRC5-FL or NLRC5-SA and analyzed by mass spectrometry revealed that both NLRC5 constructs expanded the MAP repertoire, which showed considerable overlap but also included a substantial proportion of distinct peptides. Thus, we propose that NLRC5-SA, with its ability to increase tumor immunogenicity and promote tumor growth control, could overcome the limitations of NLRC5-FL for translational immunotherapy applications.

Asunto(s)

Regulación de la Expresión Génica , Melanoma Experimental , Humanos , Animales , Ratones , Melanoma Experimental/genética , Melanoma Experimental/terapia , Genes MHC Clase I , Antígenos de Histocompatibilidad Clase I , Presentación de Antígeno , Péptidos y Proteínas de Señalización Intracelular/genética

RESUMEN

Collectin-11 (CL-11) is a recently described soluble C-type lectin that has distinct roles in embryonic development, host defence, autoimmunity, and fibrosis. Here we report that CL-11 also plays an important role in cancer cell proliferation and tumor growth. Melanoma growth was found to be suppressed in Colec11-/- mice in a s.c. B16 melanoma model. Cellular and molecular analyses revealed that CL-11 is essential for melanoma cell proliferation, angiogenesis, establishment of more immunosuppressive tumor microenvironment, and the reprogramming of macrophages to M2 phenotype within melanomas. In vitro analysis revealed that CL-11 can activate tyrosine kinase receptors (EGFR, HER3) and ERK, JNK, and AKT signaling pathways and has a direct stimulatory effect on murine melanoma cell proliferation. Furthermore, blockade of CL-11 (treatment with L-fucose) inhibited melanoma growth in mice. Analysis of open data sets revealed that COLEC11 gene expression is upregulated in human melanomas and that high COLEC11 expression has a trend toward poor survival. CL-11 also had direct stimulatory effects on human tumor cell proliferation in melanoma and several other types of cancer cells in vitro. Overall, our findings provide the first evidence to our knowledge that CL-11 is a key tumor growth-promoting protein and a promising therapeutic target in tumor growth.

Asunto(s)

Proliferación Celular , Colectinas , Melanoma Experimental , Neoplasias Cutáneas , Animales , Humanos , Ratones , Autoinmunidad , Proliferación Celular/genética , Proliferación Celular/fisiología , Colectinas/metabolismo , Melanoma Experimental/genética , Melanoma Experimental/metabolismo , Proteínas de Neoplasias , Proteínas Tirosina Quinasas Receptoras , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo , Microambiente Tumoral/genética , Microambiente Tumoral/fisiología

RESUMEN

Indoleamine 2,3 dioxygenase 1 (IDO1), a leader tryptophan-degrading enzyme, represents a recognized immune checkpoint molecule. In neoplasia, IDO1 is often highly expressed in dendritic cells infiltrating the tumor and/or in tumor cells themselves, particularly in human melanoma. In dendritic cells, IDO1 does not merely metabolize tryptophan into kynurenine but, after phosphorylation of critical tyrosine residues in the non-catalytic small domain, it triggers a signaling pathway prolonging its immunoregulatory effects by a feed-forward mechanism. We here investigated whether the non-enzymatic function of IDO1 could also play a role in tumor cells by using B16-F10 mouse melanoma cells transfected with either the wild-type Ido1 gene (Ido1WT ) or a mutated variant lacking the catalytic, but not signaling activity (Ido1H350A ). As compared to the Ido1WT -transfected counterpart (B16WT), B16-F10 cells expressing Ido1H350A (B16H350A) were characterized by an in vitro accelerated growth mediated by increased Ras and Erk activities. Faster growth and malignant progression of B16H350A cells, also detectable in vivo, were found to be accompanied by a reduction in tumor-infiltrating CD8+ T cells and an increase in Foxp3+ regulatory T cells. Our data, therefore, suggest that the IDO1 signaling function can also occur in tumor cells and that alternative therapeutic approach strategies should be undertaken to effectively tackle this important immune checkpoint molecule.

Asunto(s)

Melanoma Experimental , Triptófano , Ratones , Humanos , Animales , Linfocitos T CD8-positivos/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenasa/genética , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Proteínas de Punto de Control Inmunitario , Melanoma Experimental/genética , Transducción de Señal

RESUMEN

BACKGROUND: PCSK9 regulates cholesterol homeostasis and promotes tumorigenesis. However, the relevance of these two actions and the mechanisms underlying PCSK9's oncogenic roles in melanoma and other cancers remain unclear. METHODS: PCSK9's association with melanoma was analysed using the TCGA dataset. Empty vector (EV), PCSK9, gain-of-function (D374Y), and loss-of-function (Q152H) PCSK9 mutant were stably-expressed in murine melanoma B16 cells and studied for impact on B16 cell-derived oncogenesis in vitro and in vivo using syngeneic C57BL/6 and Pcsk9-/- mice. Intratumoral accumulation of cholesterol was determined. RNA-seq was performed on individual tumor types. Differentially-expressed genes (DEGs) were derived from the comparisons of B16 PCSK9, B16 D374Y, or B16 Q152H tumors to B16 EV allografts and analysed for pathway alterations. RESULTS: PCSK9 expression and its network negatively correlated with the survival probability of patients with melanoma. PCSK9 promoted B16 cell proliferation, migration, and growth in soft agar in vitro, formation of tumors in C57BL/6 mice in vivo, and accumulation of intratumoral cholesterol in a manner reflecting its regulation of the low-density lipoprotein receptor (LDLR): Q152H, EV, PCSK9, and D374Y. Tumor-associated T cells, CD8 + T cells, and NK cells were significantly increased in D374Y tumors along with upregulations of multiple immune checkpoints, IFNγ, and 143 genes associated with T cell dysfunction. Overlap of 36 genes between the D374Y DEGs and the PCSK9 DEGs predicted poor prognosis of melanoma and resistance to immune checkpoint blockade (ICB) therapy. CYTH4, DENND1C, AOAH, TBC1D10C, EPSTI1, GIMAP7, and FASL (FAS ligand) were novel predictors of ICB therapy and displayed high level of correlations with multiple immune checkpoints in melanoma and across 30 human cancers. We observed FAS ligand being among the most robust biomarkers of ICB treatment and constructed two novel and effective multigene panels predicting response to ICB therapy. The profiles of allografts produced by B16 EV, PCSK9, D374Y, and Q152H remained comparable in C57BL/6 and Pcsk9-/- mice. CONCLUSIONS: Tumor-derived PCSK9 plays a critical role in melanoma pathogenesis. PCSK9's oncogenic actions are associated with intratumoral cholesterol accumulation. PCSK9 systemically affects the immune system, contributing to melanoma immune evasion. Novel biomarkers derived from the PCSK9-network effectively predicted ICB therapy responses.

Asunto(s)

Melanoma Experimental , Melanoma , Humanos , Ratones , Animales , Proproteína Convertasa 9/genética , Proteína Ligando Fas , Ratones Endogámicos C57BL , Melanoma/genética , Melanoma Experimental/genética , Melanoma Experimental/patología , Moléculas de Adhesión Celular , Factores de Intercambio de Guanina Nucleótido , Proteínas Activadoras de GTPasa