Murine B16 Melanoma Research Articles

Caerin 1.1 and 1.9 peptides halt B16 melanoma metastatic tumours via expanding cDC1 and reprogramming tumour macrophages

BackgroundCancer immunotherapy, particularly immune checkpoint inhibitors (ICBs) such as anti-PD-1 antibodies, has revolutionised cancer treatment, although response rates vary among patients. Previous studies have demonstrated that caerin 1.1 and 1.9, host-defence peptides from the Australian tree frog, enhance the effectiveness of anti-PD-1 and therapeutic vaccines in a murine TC-1 model by activating tumour-associated macrophages intratumorally.MethodsWe employed a murine B16 melanoma model to investigate the therapeutic potential of caerin 1.1 and 1.9 in combination with anti-CD47 and a therapeutic vaccine (triple therapy, TT). Tumour growth of caerin-injected primary tumours and distant metastatic tumours was assessed, and survival analysis conducted. Single-cell RNA sequencing (scRNAseq) of CD45+ cells isolated from distant tumours was performed to elucidate changes in the tumour microenvironment induced by TT.ResultsThe TT treatment significantly reduced tumour volumes on the treated side compared to untreated and control groups, with notable effects observed by Day 21. Survival analysis indicated extended survival in mice receiving TT, both on the treated and distant sides. scRNAseq revealed a notable expansion of conventional type 1 dendritic cells (cDC1s) and CD4+CD8+ T cells in the TT group. Tumour-associated macrophages in the TT group shifted toward a more immune-responsive M1 phenotype, with enhanced communication observed between cDC1s and CD8+ and CD4+CD25+ T cells. Additionally, TT downregulated M2-like macrophage marker genes, particularly in MHCIIhi and tissue-resident macrophages, suppressing Cd68 and Arg1 expression across all macrophage types. Differential gene expression analysis highlighted pathway alterations, including upregulation of oxidative phosphorylation and MYC target V1 in Arg1hi macrophages, and activation of pro-inflammatory pathways in MHCIIhi and tissue-resident macrophages.ConclusionOur findings suggest that caerin 1.1 and 1.9, combined with immunotherapy, effectively modulate the tumour microenvironment in primary and secondary tumours, leading to reduced tumour growth and enhanced systemic immunity. Further investigation into these mechanisms could pave the way for improved combination therapies in advanced melanoma treatment.

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.

KDM4B Histone Demethylase Inhibition Attenuates Tumorigenicity of Malignant Melanoma Cells by Overriding the p53-Mediated Tumor Suppressor Pathway.

Despite significant advances in the treatment of cutaneous melanoma (hereaftermelanoma), the prognosis remains less favorable due to therapeutic resistance, which is presumably linked to epigenetic dysregulation. We hypothesized that the histone lysine demethylase KDM4B could play a pivotal role in controlling therapy-resistant melanoma. To validate our hypothesis, we retrieved RNA sequencing data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA)program and observed upregulation of KDM4B in both primary and metastatic melanoma, which was associated with poor survival. To explore its role, we used murine B16, human SK-MEL-5, and G-361 melanoma cells as in vitro models of melanoma. We found that KDM4B inhibition using NCGC00244536 increased global levels of H3K9me3 and downregulated the expressions of cell cycle progression-related genes Cdk1, Cdk4, Ccnb1, and Ccnd1. Moreover, genetic ablation of KDM4B or its chemical inhibition using NCGC00244536 reduced p53 production by upregulating MDM2, which enhances the proteolytic degradation of p53. Interestingly, despite the reduction of p53, these interventions augmented apoptosis and senescence-induced cell death by activating pathways downstream of p53, as evidenced by reduced levels of pro-survival Bcl-2 and Bcl-xL proteins and increased production of pro-apoptotic cleaved caspase-3, caspase-7, Bax, and the senescence inducer Cdkn1a. Compared to the FDA-approved anti-melanoma agent dacarbazine, NCGC00244536 exhibited more pronounced cytotoxic and antiproliferative effects in melanoma cells. Importantly, NCGC00244536 demonstrated minimal cytotoxicity to low Kdm4b-expressing mouse embryonic fibroblasts. In conclusion, our findings suggest that KDM4B inhibition can override the antitumor effect of p53, and potentially serve as a therapeutic strategy for melanoma.

Targeting ZC3H11A elicits immunogenic cancer cell death through augmentation of antigen presentation and interferon response

Zinc finger CCCH containing 11A (ZC3H11A) is a stress-induced protein that is upregulated in various conditions, such as heat shock and virus infection. It has also been reported to be upregulated in certain cancers. The aim of this study was to evaluate the feasibility of targeting ZC3H11A as a therapeutic approach for cancer treatment, using nuclease-resistant, affinity-enhanced antisense oligonucleotide (ASO). An ASO targeting ZC3H11A was validated and evaluated in vitro and in the B16 melanoma model in vivo. Antigen presentation, interferon response, cell proliferation and apoptosis were transcriptionally affected. These findings were validated on the protein level by upregulation of major histocompatibility complex I (MHC-I), an increased secretion of interferon-β (IFN-β), and induction of apoptosis observed as upregulation of caspases and annexin V. Immunogenic features of the induced apoptosis were evidenced by surface exposure of calreticulin (CRT) and the secretion of ATP leading to enhanced dendritic cell (DC) phagocytosis, maturation, and activation. Treatment with the ZC3H11A-targeted ASO had limited efficacy in vivo while constitutive lentiviral shRNA knockdown of ZC3H11A in murine B16 melanoma cells, and human Hela cells led to reduced tumor growth with prolonged survival of mice, validating ZC3H11A as a relevant target for cancer therapy.

Fatty acid derivatization and cyclization of the immunomodulatory peptide RP-182 targeting CD206high macrophages improves anti-tumor activity.

As tumor-associated macrophages (TAMs) exercise a plethora of pro-tumor and immune evasive functions, novel strategies targeting TAMs to inhibit tumor progression have emerged within the current arena of cancer immunotherapy. Activation of the mannose receptor 1 (Mrc1; CD206) is a recent approach that recognizes immune suppressive CD206high M2-like TAMs as a drug target. Ligation of CD206 both induces reprogramming of CD206high TAMs towards a pro-inflammatory phenotype and selectively triggers apoptosis in these cells. CD206-activating therapeutics are currently limited to the linear, 10mer peptide RP-182, 1, which is not a drug candidate. Here we sought to identify a better suitable candidate for future clinical development by synthesizing and evaluating a series of RP-182 analogues. Surprisingly, fatty acid derivative 1a (RP-182-PEG3-K(palmitic acid)) not only showed improved stability but also increased affinity to the CD206 receptor through enhanced interaction with a hydrophobic binding motif of CD206. Peptide 1a showed superior in vitro activity in cell-based assays of macrophage activation which was restricted to CD206high M2-polarized macrophages. Improvement of responses was disproportionally skewed towards improved induction of phagocytosis including cancer cell phagocytosis. 1a reprogrammed the immune landscape in genetically engineered murine KPC pancreatic tumors towards increased innate immune surveillance and improved tumor control, and effectively suppressed tumor growth of murine B16 melanoma allografts.

Copper(II) Methacrylate Complexes with Imidazole Derivatives-Structural, Spectral and Antitumor Features.

A series of five novel copper(II) complexes with imidazole derivatives having general core Cu(R-Im)2(Macr)2 (Macr = methacrylate anion; R-Im = 2-methylimidazole/2-MeIm, 4-methylimidazole/4-MeIm, 2-ethylimidazole/2-EtIm, 2-isopropylimidazole/2-iPrIm) has been synthesized and characterized by elemental analysis, Fourier Transform Infrared spectroscopy (FTIR), electronic reflectance spectroscopy, cyclic voltammetry, thermal analysis and single crystal X-ray diffraction. All complexes crystalize in a monoclinic crystal system and form a complex supramolecular network developed through hydrogen bonds. The stereochemistry of the copper ion is distorted octahedral except for the compound with 4-methylimidazole for which the geometry is square-pyramidal. The imidazole derivatives act as unidentate while methacrylate ions are chelated except for compound with 4-methylimidazole where is unidentate. All ligands and complexes inhibited B16 murine melanoma cells in a micromolar range, but the complex with 2-isopropylimidazole was more active. Furthermore, all species do not affect the healthy BJ cells in the concentration range used for assays.

The expression of PD-L1 on tumor-derived exosomes enhances infiltration and anti-tumor activity of αCD3 × αPD-L1 bispecific antibody-armed T cells

Anti-cluster of differentiation (CD) 3 × α programmed death-ligand 1 (PD-L1) bispecific T-cell engager (BsTE)-bound T-cells (BsTE:T) are a promising new cancer treatment agent. However, the mechanisms of action of bispecific antibody-armed activated T-cells are poorly understood. Therefore, this study aimed to investigate the anti-tumor mechanism and efficacy of BsTE:T. The BsTE:T migration was assessed in vivo and in vitro using syngeneic and xenogeneic tumor models, flow cytometry, immunofluorescence staining, transwell migration assays, microfluidic chips, Exo View R100, western blotting, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 technology. In murine B16 melanoma, MC38 colon cancer, and human multiple myeloma cells, BsTE:T exhibited superior tumor elimination relative to that of T-cells or BsTE alone. Moreover, BsTE:T migration into tumors was significantly enhanced owing to the presence of PD-L1 in tumor cells and secretion of PD-L1-containing exosomes. Furthermore, increased infiltration of CD44highCD62Llow effector memory CD8+ T-cells into tumors was closely associated with the anti-tumor effect of BsTE:T. Therefore, BsTE:T is an innovative potential anti-tumor therapy, and exosomal PD-L1 plays a crucial role both in vitro and in vivo in the anti-tumor activity of BsTE:T.Graphical abstract

Co-delivery of STING and TLR7/8 agonists in antigen-based nanocapsules to dendritic cells enhances CD8+ T cell-mediated melanoma remission

Insufficient efficacy of tumor vaccines still represents a major challenge due to poor adjuvant potency. Combining antigen and adjuvants of different classes bears the potential to induce a broad spectrum of anti-tumor immune responses. Here we demonstrate a novel nanocarrier (NC)-based vaccine combining the type I interferon-triggering STING agonist diamidobenzimidazole (diABZI) compound 3 and the well-established TLR7/8 agonist resiquimod (R848). Encapsulation of both adjuvants into polymeric nanocapsules enables the simultaneous transport of immunostimulatory molecules with tumor antigens. Thereby achieved co-delivery further improved DC stimulation and subsequent anti-tumor immune responses.Combined encapsulation of R848 and diABZI enhanced DC activation and induced stronger antigen-specific T cell responses compared to the single adjuvant NC treatment or using soluble forms of antigens and adjuvants in vitro and in vivo. This was determined by the vigorous expression of CD80, CD83, and CD86. Furthermore, the dual adjuvant therapy initiated the highest secretion levels of different pro-inflammatory cytokines and chemokines.Moreover, a substantial antigen-specific T cell proliferation led to robust tumor remission in a murine B16 melanoma model. Subcutaneous administration of R848/diABZI-loaded NCs induced enhanced infiltration of CD4+ and CD8+ T cells as well as neutrophils in tumor-draining lymph nodes (LN) and tumor tissue. Encapsulating the melanoma-specific antigenic peptide of TRP2 into the adjuvant-loaded NCs reduced the growth of B16 melanoma and prolonged the overall survival. The herein presented novel anti-tumor vaccination strategy avoids the use of structural compounds, increases the antigen load of dendritic cells, uses a fixed combination of antigen and two potent adjuvants and bears the potential to induce vigorous antigen-specific anti-cancer immunity.

Oligoribonucleotides in complexes with D-mannitol alter cell cycle and cause apoptosis in murine melanoma B16 cells

Oligoribonucleotides in complexes with D-mannitol alter cell cycle and cause apoptosis in murine melanoma B16 cells

Tumor- and Fibroblast-Derived Cell-Free DNAs Differently Affect the Progression of B16 Melanoma In Vitro and In Vivo.

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.

Abstract 3125: TCX-101, a novel antibody-drug conjugate targeting a tumor-associated carbohydrate antigen for the treatment of solid tumors

Abstract Tumor-associated carbohydrate antigens (TACAs) are short oligosaccharides expressed on the surface of cancer cells and play key roles in cellular communication, immune evasion, apoptosis and metastasis. TACAs are therefore interesting targets for antibody-based therapies in cancer. We have generated an antibody (TCX-101) against a TACA structure with improved binding affinity compared to other monoclonal antibodies (mAbs) against the same target as shown by surface plasmon resonance (~ 10x superior KD), as well as high level of specificity against glycan species related to the target, as accessed by glycan array, flow cytometry, and immunocytochemistry or immunofluorescence. Immunohistochemistry studies on fresh-frozen tissue microarrays showed high expression of the target in various solid tumors (e.g. gastrointestinal, lung, and breast) and only low expression in normal tissues. In vitro, TCX-101 has ~ 4x higher maximum binding, ~ 2x faster binding kinetics, ~ 4x faster cellular internalization and induces ~ 2x higher antibody-dependent cellular cytotoxicity than a reference antibody. Monomethyl auristatin E (MMAE) was used in a drug-antibody ratio (DAR) of 4 to generate an antibody-drug conjugate (ADC). This ADC was effective in in vitro toxicity assays against murine B16 melanoma cells induced to express the target (measurable effect on WT cells), as well as human breast cancer MCF7 WT cells (~ 25x less activity on target-knockout MCF7 cells, Table 1). When tested in vivo, TCX-101 was highly effective in two different xenograft mouse models (B16, MCF7) with more than 95% tumor growth inhibition compared to vehicle, and no signs of toxicity (no weight loss, no histophatological findings). A fully humanized version of TCX-101 with improved binding properties (EC50 6.27 nM vs. 8.13 nM) was generated and will be evaluated in further in vivo experiments. In conclusion, TCX-101 is a promising ADC for the treatment of various solid tumors. IC50 [nM] TCX-101-MMAE 4 DAR B16 KI 7.64 B16 WT no killing observed MCF7 WT 1.97 MCF7 KO 45.97 Citation Format: Fausto G. Gomes, Francesco Muraca, Gustavo M. Schmidt Garcia Moreira, Kathrin Rösch, Maria Bräutigam, Peter Sondermann, Matthias Ocker. TCX-101, a novel antibody-drug conjugate targeting a tumor-associated carbohydrate antigen for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3125.

Abstract 1371: SLAMF9 promotes tumor progression and immunotherapy resistance by reshaping the tumor microenvironment

Abstract Tumor prognosis and immunotherapy efficacy coincides with the infiltration ratio and functional status of immune cells in the tumor microenvironment (TME). Signaling lymphocytes activating molecule factors (SLAMFs) has been reported to play a key role in regulating tumor immunity. Herein, using multi cohorts, in vitro and in vivo experiments, we showed that SLAMF9 worsens tumor and suppresses immune therapy responses by remodeling TME. A pan-cancer analysis showed that SLAMF9 had relatively high transcriptional levels within tumor tissues compared with normal tissues across most cancer types. High SLAMF9 expression is associated with poor prognosis and anti-PD-L1 therapy resistance in advanced clear cell renal cell carcinoma cohorts and metastatic urothelial cancer cohorts. SLAMF9 expression was markedly upregulated in anti-CTLA-4-resistant murine B16 melanoma compared with parental tumors. In particular, SLAMF9 expression was generally negatively correlated with CD8+T cell infiltration score in 12159 patients of 40 cancer types even using different immune cell infiltrating algorithms. Although in vitro experiments have shown that SLAMF9 knockdown has almost no effect on the malignant phenotype of tumor cells, subcutaneous melanoma and lung adenocarcinoma with SLAMF9 deficiency grew slowly, which featured with increased infiltration of CD8+T and PD-1+cells. More importantly, SLAMF9-knockdown significantly increases the sensitivity of subcutaneous melanoma to anti-CTLA-4 inhibitor or anti-PD-L1 antibodies and improved the survival benefits of tumor-bearing mice. This work highlights SLAMF9 as a new target in reshaping the tumor immune microenvironment by controlling the functional status of CD+8 T cells and to improve the efficacy of immunotherapy. Citation Format: Tao Fan, Chu Xiao, Ziqin Deng, Wenpeng Cai, He Tian, Liyu Wang, Chunxiang Li, Jie He. SLAMF9 promotes tumor progression and immunotherapy resistance by reshaping the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1371.

Elesclomol Loaded Copper Oxide Nanoplatform Triggers Cuproptosis to Enhance Antitumor Immunotherapy.

The induction of cuproptosis, a recently identified form of copper-dependent immunogenic cell death, is a promising approach for antitumor therapy. However, sufficient accumulation of intracellular copper ions (Cu2+) in tumor cells is essential for inducing cuproptosis. Herein, an intelligent cuproptosis-inducing nanosystem is constructed by encapsulating copper oxide (CuO) nanoparticles with the copper ionophore elesclomol (ES). After uptake by tumor cells, ES@CuO is degraded to release Cu2+ and ES to synergistically trigger cuproptosis, thereby significantly inhibiting the tumor growth of murine B16 melanoma cells. Moreover, ES@CuO further promoted cuproptosis-mediated immune responses and reprogrammed the immunosuppressive tumor microenvironment by increasing the number of tumor-infiltrating lymphocytes and secreted inflammatory cytokines. Additionally, combining ES@CuO with programmed cell death-1 (PD-1) immunotherapy substantially increased the antitumor efficacy in murine melanoma. Overall, the findings of this study can lead to the use of a novel strategy for cuproptosis-mediated antitumor therapy, which may enhance the efficacy of immune checkpoint inhibitor therapy.

Efficacy and safety of guttiferone E in melanoma-bearing mice.

Melanoma, an aggressive and potentially fatal skin cancer, is constrained by immunosuppression, resistance, and high toxicity in its treatment. Consequently, there is an urgent need for innovative antineoplastic agents. Therefore, this study investigated the antimelanoma potential of guttiferone E (GE). In an allogeneic murine B16 melanoma model, GE was administered subcutaneously and intraperitoneally. Antitumor evaluation included tumor volume/weight measurements and histopathological and immunohistochemical analysis. Furthermore, the toxicity of the treatments was evaluated through body/organ weights, biochemical parameters, and genotoxicity. Subcutaneous administration of 20 mg/kg of GE resulted in a significant reduction in both tumor volume and weight, effectively suppressing melanoma cell proliferation as evidenced by a decrease in mitotic figures. The tumor growth inhibition rate was equivalent to 54%. This treatment upregulated cleaved caspase-3, indicating apoptosis induction. On the other hand, intraperitoneal administration of GE showed no antimelanoma effect. Remarkably, GE treatments exhibited no toxicity, evidenced by non-significant differences in body weight gain, as well as organ weight, biochemical parameters of nephrotoxicity and hepatotoxicity, and genotoxic damage. This study revealed, for the first time, the efficacy of subcutaneous administration of GE in reducing melanoma, in the absence of toxicity. Furthermore, it was observed that the apoptotic signaling pathway is involved in the antimelanoma property of GE. These findings offer valuable insights for further exploring GE's therapeutic applications in melanoma treatment.

Lithium salts cytotoxicity and accumulation in melanoma cells in vitro.

Boron neutron capture therapy is a perspective selective technology for the destruction of cancer cells, while the use of lithium instead of boron may represent a new and promising vector for the development of neutron capture therapy (NCT). The aim of the study was a comparative assessment of the cytotoxicity of various lithium salts, as well as an analysis of the accumulation of lithium in tumor cells in vitro to determine the possibility of using lithium in NCT. The cytotoxicity of lithium salts was determined using MTT-test and colony forming assay on human fibroblasts BJ-5ta, human skin melanoma SK-Mel-28, and mouse skin melanoma B16 cell lines. An assessment of lithium concentration in cells was performed using inductively coupled plasma atomic emission spectrometry. Our results showed that three different lithium salts at a concentration of 40 μg/ml are not toxic for both tumor and normal cells. The highest uptake values were obtained on murine melanoma B16 cells when exposed to lithium carbonate (0.8 μg/106 cells); however, human melanoma SK-Mel-28 cells effectively accumulated both lithium carbonate and lithium citrate (about 0.46 μg/106 cells for two salts). Thus, our results demonstrate a range of non-toxic doses of lithium salts and a high uptake of lithium by tumor cells, which indicates the possibility to use the lithium in NCT.

Electrochemical Nanopipette Sensor for In Vitro/In Vivo Detection of Cu2+ Ions.

In vitro/in vivo detection of copper ions is a challenging task but one which is important in the development of new approaches to the diagnosis and treatment of cancer and hereditary diseases such as Alzheimer's, Wilson's, etc. In this paper, we present a nanopipette sensor capable of measuring Cu2+ ions with a linear range from 0.1 to 10 μM in vitro and in vivo. Using the gold-modified nanopipette sensor with a copper chelating ligand, we evaluated the accumulation ability of the liposomal form of an anticancer Cu-containing complex at three levels of biological organization. First, we detected Cu2+ ions in a single cell model of human breast adenocarcinoma MCF-7 and in murine melanoma B16 cells. The insertion of the nanoelectrode did not result in leakage of the cell membrane. We then evaluated the distribution of the Cu-complex in MCF-7 tumor spheroids and found that the diffusion-limited accumulation was a function of the depth, typical for 3D culture. Finally, we demonstrated the use of the sensor for Cu2+ ion detection in the brain of an APP/PS1 transgenic mouse model of Alzheimer's disease and tumor-bearing mice in response to injection (2 mg kg-1) of the liposomal form of the anticancer Cu-containing complex. Enhanced stability and selectivity, as well as distinct copper oxidation peaks, confirmed that the developed sensor is a promising tool for testing various types of biological systems. In summary, this research has demonstrated a minimally invasive electrochemical technique with high temporal resolution that can be used for the study of metabolism of copper or copper-based drugs in vitro and in vivo.

BDE-209 exposure in murine melanoma (B16–F1) cells modulates tumor malignancy and progression in vivo

Melanoma is a type of skin cancer considered aggressive due to its high metastatic ability and rapid progression to other tissues and organs. BDE-209 (2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether) is an additive used as a flame retardant and classified as a persistent organic pollutant that has a high bioaccumulation capacity due to its lipophilic nature. This substance has already been detected in rivers, air, soil, plants and even in different human biological samples, such as plasma, umbilical cord blood and breast milk, revealing a great concern to human populations. Thus, in the current study we investigated whether prior exposure of murine melanoma B16–F1 cells to BDE-209 modulates in vivo progression and malignancy of melanoma. B16–F1 cells were cultured and exposed in vitro to BDE-209 (0.01, 0.1 e 1 nM) for 15 days and then inoculated, via caudal vein, in C57BL/6 mice for experimental metastasis analysis after 20 days. Inoculation of BDE-209-exposed cells resulted in 82% increase of metastasis colonized area in the lungs of mice, downregulation of tumor suppressors genes, such as Timp3 and Reck, decrease of lipid peroxidation and increase of systemic and local inflammatory response. These findings are related to melanoma progression. Additionally, the histopathological analysis revealed greater number of focal points of metastases in the lungs and invasiveness of metastases to the mice brain (89%). The results showed that exposure to BDE-209 may alter the phenotype of B16–F1 cells, worsening their metastatic profile. Current data showed that BDE-209 may interfere with the prognosis of melanoma by modulating cells with less invasiveness capacity to a more aggressive profile.

Rational Design, Multistep Synthesis and in Vitro Evaluation of Poly(glycerol) Functionalized Nanodiamond Conjugated with Boron-10 Cluster and Active Targeting Moiety for Boron Neutron Capture Therapy.

Boron neutron capture therapy (BNCT), advanced cancer treatment utilizing nuclear fission of 10 B atom in cancer cells, is attracting increasing attention. As 10 B delivery agent, sodium borocaptate (10 BSH, 10 B12 H11 SH ⋅ 2Na), has been used in clinical studies along with L-boronophenylalanine. Recently, this boron cluster has been conjugated with lipids, polymers or nanoparticles to increase selectivity to and retentivity in tumor. In this work, anticancer nanoformulations for BNCT are designed, consisting of poly(glycerol) functionalized detonation nanodiamonds (DND-PG) as a hydrophilic nanocarrier, the boron cluster moiety (10 B12 H11 2- ) as a dense boron-10 source, and phenylboronic acid or RGD peptide as an active targeting moiety. Some hydroxy groups in PG were oxidized to carboxy groups (DND-PG-COOH) to conjugate the active targeting moiety. Some hydroxy groups in DND-PG-COOH were then transformed to azide to conjugate 10 B12 H11 2- through click chemistry. The nanodrugs were evaluated in vitro using B16 murine melanoma cells in terms of cell viability, BNCT efficacy and cellular uptake. As a result, the 10 B12 H11 2- moiety is found to facilitate cellular uptake probably due to its negative charge. Upon thermal neutron irradiation, the nanodrugs with 10 B12 H11 2- moiety exhibited good anticancer efficacies with slight differences with and without targeting moiety.

Beta IV spectrin inhibits the metastatic growth of melanoma by suppressing VEGFR2-driven tumor angiogenesis.

Tumor-associated angiogenesis mediates the growth and metastasis of most solid cancers. Targeted therapies of the VEGF pathways can effectively block these processes but often fail to provide lasting benefits due to acquired resistance and complications. Recently, we discovered βIV -spectrin as a powerful regulator of angiogenesis and potential new target. We previously reported that βIV -spectrin is dynamically expressed in endothelial cells (EC) to induce VEGFR2 protein turnover during development. Here, we explored how βIV -spectrin influences the tumor vasculature using the murine B16 melanoma model and determined that loss of EC-specific βIV -spectrin dramatically promotes tumor growth and metastasis. Intraperitoneally injected B16 cells formed larger tumors with increased tumor vessel density and greater propensity for metastatic spread particularly to the chest cavity and lung compared to control mice. These results support βIV -spectrin as a key regulator of tumor angiogenesis and a viable vascular target in cancer.

Proinflammatory allogeneic dendritic cells enhance the therapeutic efficacy of systemic anti-4-1BB treatment.

As an immune adjuvant, proinflammatory allogeneic dendritic cells (AlloDCs) have demonstrated promising immune-priming effects in several preclinical and clinical studies. The effector cells, including NK cells and T cells are widely acknowledged as pivotal factors in the effectiveness of cancer immunotherapy due to their ability to selectively identify and eradicate malignant cells. 4-1BB, as a costimulatory receptor, plays a significant role in the stimulation of effector cell activation. This study evaluated the anti-tumor effects when combining intratumoral administration of the immune-adjuvant AlloDCs with systemic α4-1BB treatment directly acting on effector cells. In both the CT-26 murine colon carcinoma model and B16 murine melanoma model, AlloDCs demonstrated a significant enhancement in the therapeutic efficacy of α4-1BB antibody. This enhancement was observed through the delayed growth of tumors and prolonged survival. Analysis of the tumor microenvironment (TME) in the combined-treatment group revealed an immune-inflamed TME characterized by increased infiltration of activated endogenous DCs and IFNγ+ CD8+ T cells, showing reduced signs of exhaustion. Furthermore, there was an augmented presence of tissue-resident memory (TRM) CD8+ T cells (CD103+CD49a+CD69+). The combination treatment also led to increased infiltration of CD39+CD103+ tumor-specific CD8+ T cells and neoantigen-specific T cells into the tumor. Additionally, the combined treatment resulted in a less immunosuppressive TME, indicated by decreased infiltration of myeloid-derived suppressor cells and Tregs. These findings suggest that the combination of intratumoral AlloDCs administration with systemic agonistic α4-1BB treatment can generate a synergistic anti-tumor response, thereby warranting further investigation through clinical studies.