Melanoma Model Research Articles

Discovery of FHD-286, a First-in-Class, Orally Bioavailable, Allosteric Dual Inhibitor of the Brahma Homologue (BRM) and Brahma-Related Gene 1 (BRG1) ATPase Activity for the Treatment of SWItch/Sucrose Non-Fermentable (SWI/SNF) Dependent Cancers.

BRM (SMARCA2) and BRG1 (SMARCA4) are mutually exclusive ATPase subunits of the mSWI/SNF (BAF) chromatin remodeling complex. BAF is an attractive therapeutic target because of its role in transcription, and mutations in the subunits of BAF are common in cancer and neurological disorders. Herein, we report the discovery of compound 1 (FHD-286) as a potent allosteric inhibitor of the dual ATPase subunits from a high-throughput screening hit with a BRM IC50 of ∼27 μM. FHD-286 is an orally bioavailable compound with antitumor activity in mouse xenograft models of uveal melanoma and acute myeloid leukemia and is being evaluated in Phase 1 clinical trials.

Dual Strategies Based on Golgi Apparatus/Endoplasmic Reticulum Targeting and Anchoring for High-Efficiency siRNA Delivery and Tumor RNAi Therapy.

Endolysosomal degradation of small interfering RNA (siRNA) significantly reduces the efficacy of RNA interference (RNAi) delivered by nonviral systems. Leveraging Golgi apparatus/endoplasmic reticulum (Golgi/ER) transport can help siRNA bypass the endolysosomal degradation pathway, but this approach may also result in insufficient siRNA release and an increased risk of Golgi/ER-mediated exocytosis. To address these challenges, we developed two distinct strategies using a nanocomplex of cell-penetrating poly(disulfide)s and chondroitin sulfate, which enhances targeted internalization, Golgi transport, and rapid cytoplasmic release of loaded siRNA. In the first strategy, monensin synergy was found to enhance RNAi by inhibiting both exocytosis and autophagic degradation. In the second strategy, a "directed sorting" approach based on KDEL peptide-mediated retrograde transport was introduced. By conjugation of the KDEL peptide to chondroitin sulfate, Golgi-to-ER transport was promoted, reducing "random" Golgi/ER-related exocytosis. These two strategies operate alternatively to achieve high-efficiency RNAi with a significant therapeutic potential. Notably, in a mouse melanoma model using anti-Bcl-2 siRNA, the strategies achieved tumor inhibition rates of 87.1 and 90.1%, respectively. These two strategies, based on "targeting" and "anchoring" Golgi/ER, provide potent solutions to overcome the challenges of cellular internalization, intracellular release, and exocytosis in efficient siRNA delivery.

Generation of a genetically engineered porcine melanoma model featuring oncogenic control through conditional Cre recombination

Melanoma is a serious type of skin cancer that originates from melanocytes. Rodent melanoma models have provided valuable insights into melanoma pathology; however, they often lack applicability to humans owing to genetic, anatomical, physiological, and metabolic differences. Herein, we developed a transgenic porcine melanoma model that closely resembles humans via somatic cell nuclear transfer (SCNT). Our model features the conditional oncogenes cassettes, TP53R167H and human BRAFV600E, controlled by melanocyte-specific CreER recombinase. After SCNT, transgenic embryos developed normally, with the capacity to develop porcine embryonic stem cells. Seven transgenic piglets with oncogene cassettes were born through embryo transfer. We demonstrated that Cre recombination-mediated oncogene activation remarkably triggered the mitogen-activated protein kinase pathway in vitro. Notably, intradermal injection of 4-hydroxytamoxifen activated oncogene cassettes in vivo, resulting in melanocytic lesions resembling hyperpigmented nevi with increased proliferative properties similar to early human melanomas. This melanoma-inducing system, heritably transmitted to offspring, supports large-scale studies. The novel porcine model provides a valuable tool for elucidating melanoma development and metastasis mechanism, advancing translational medicine, and facilitating preclinical evaluation of new anticancer drugs.

Hybrid lipid nanoparticles with tumor antigen-primed dendritic cell membranes for post-surgical tumor immunotherapy.

Post-surgical tumor recurrence poses a major challenge in cancer treatment due to residual tumor cells and surgery-induced immunosuppression. Here, we developed hybrid nanoparticles, termed T-DCNPs, designed to promote antigen-specific activation of cytotoxic CD8+ T cells while concurrently inhibiting immunosuppressive pathways within the tumor microenvironment. T-DCNPs were formulated by co-extruding lipid nanoparticles containing a transforming growth factor β inhibitor with dendritic cells that were pre-treated with autologous neoantigens derived from surgically excised tumors. By using whole tumor antigens rather than specific peptides, T-DCNPs effectively overcame tumor heterogeneity and elicited a robust, targeted immune response. In vitro studies showed that T-DCNPs enhanced CD8+ T cell proliferation and reduced programmed death-1 (PD-1) expression, leading to increased antitumor cytotoxicity. In vivo experiments, involving intratumoral injections of T-DCNPs in distant tumor and post-surgical melanoma models, demonstrated a significant reduction in distant tumor growth, decreased recurrence rates, and extended survival compared to control groups. Flow cytometry and immunohistochemistry analyses further confirmed the enhanced infiltration of activated CD8+ T cells and a marked reduction in immunosuppressive markers, including PD-1 and Foxp3, within the treated tumors. These results suggest that T-DCNPs, through the dual mechanisms of tumor antigen-specific T cell activation and immune modulation, offer a promising strategy to prevent tumor recurrence following surgery and could potentially improve the efficacy of postoperative cancer immunotherapy.

Dendrimer-Mediated Generation of a Metal-Phenolic Network for Antibody Delivery to Elicit Improved Tumor Chemo/Chemodynamic/Immune Therapy.

To simplify the composition and improve the efficacy of metal-phenolic network (MPN)-based nanomedicine, herein, we designed an MPN platform to deliver programmed death ligand-1 (PD-L1) antibody (anti-PD-L1) for combined tumor chemo/chemodynamic/immune therapy. Here, generation 5 poly(amidoamine) dendrimers conjugated with gossypol (Gos) through boronic ester bonds were used as a synthetic polyphenol to coordinate Mn2+, and then complexed with anti-PD-L1 to obtain the nanocomplexes (for short, DPGMA). The prepared DPGMA exhibited good water dispersibility with a hydrodynamic size of 166.3 nm and tumor-microenvironment-responsive drug release behavior. The integration of Gos and Mn2+ within the DPGMA resulted in significant tumor inhibition and immunogenic cell death activation through Gos-mediated chemotherapy and Mn2+-catalyzed chemodynamic therapy, respectively, thereby leading to significant dendritic cell maturation due to the role of Mn2+ played to mediate the activation of the stimulator of interferon genes (STING) pathway. Moreover, the complexed anti-PD-L1 promoted the recognition and uptake of nanocomplexes by PD-L1-overexpressed tumors through antibody targeting, thereby achieving combinational chemo/chemodynamic/immune therapy in a mouse melanoma model, where the immunotherapy modes combined three parts of activation via chemotherapy/CDT-mediated ICD, Mn2+-mediated STING activation, and antibody-mediated immune checkpoint blockade. With the Mn2+-endowed r1 relaxivity (1.38 mM-1 s-1), the DPGMA nanocomplexes can also be used for tumor MR imaging. The designed dendrimer-mediated MPN platform may be developed as an advanced nanomedicine to tackle other cancer types.

The adaptor protein Miro1 modulates horizontal transfer of mitochondria in mouse melanoma models.

Recent research has shown that mtDNA-deficient cancer cells (ρ0 cells) acquire mitochondria from tumor stromal cells to restore respiration, facilitating tumor formation. We investigated the role of Miro1, an adaptor protein involved in movement of mitochondria along microtubules, in this phenomenon. Inducible Miro1 knockout (Miro1KO) mice markedly delayed tumor formation after grafting ρ0 cancer cells. Miro1KO mice with fluorescently labeled mitochondria revealed that this delay was due to hindered mitochondrial transfer from the tumor stromal cells to grafted B16 ρ0 cells, which impeded recovery of mitochondrial respiration and tumor growth. Miro1KO led to the perinuclear accumulation of mitochondria and impaired mobility of the mitochondrial network. Invitro experiments revealed decreased association of mitochondria with microtubules, compromising mitochondrial transfer via tunneling nanotubes (TNTs) in mesenchymal stromal cells. Here we show the role of Miro1 in horizontal mitochondrial transfer in mouse melanoma models invivo and its involvement with TNTs.

Ferroptosis: A Targetable Vulnerability for Melanoma Treatment.

Melanoma is a devastating form of skin cancer characterized by a high mutational burden, limited treatment success, and dismal prognosis. Although immunotherapy and targeted therapies have significantly revolutionized melanoma treatment, the majority of patients fail to achieve durable responses, highlighting the urgent need for novel therapeutic strategies. Ferroptosis, an iron-dependent form of regulated cell death driven by the overwhelming accumulation of lipid peroxides, has emerged as a promising therapeutic approach in preclinical melanoma models. A deeper understanding of the ferroptosis landscape in melanoma based on its biology characteristics, including phenotypic plasticity, metabolic state, genomic alterations, and epigenetic changes, as well as the complex role and mechanisms of ferroptosis in immune cells could provide a foundation for developing effective treatments. In this review, we outline the molecular mechanisms of ferroptosis, decipher the role of melanoma biology in ferroptosis regulation, reveal the therapeutic potential of ferroptosis in melanoma, and discuss the pressing questions that should guide future investigations into ferroptosis in melanoma.

Decavanadate Compound Displays In Vitro and In Vivo Antitumor Effect on Melanoma Models

Decavanadate Compound Displays In Vitro and In Vivo Antitumor Effect on Melanoma Models

Thermosensitive hydrogel delivery of BCG lysates and tumor antigens: A novel strategy for melanoma immunoprevention and therapeutics.

Melanoma, recognized as one of the most aggressive forms of skin cancer, continues to show a steady rise in global incidence. While Bacillus Calmette-Guérin (BCG) has been identified as a potential intralesional therapy for melanoma, its therapeutic efficacy remains suboptimal. This study introduces a novel thermosensitive hydrogel formulated with BCG lysates and either OVA peptide or tumor cell lysates (PPP-BCG-OVA/TL). The hydrogel demonstrated the ability to elicit a robust systemic tumor antigen-specific T cell response and significantly enhanced the infiltration of CD45+ leukocytes, macrophages, CD8+ T cells, and natural killer (NK) cells into the tumor microenvironment. As a result, vaccination with PPP-BCG-OVA/TL hydrogel effectively inhibited tumor growth and extended survival in mouse models of subcutaneous melanoma in both preventive and therapeutic contexts. These findings highlight the potential to markedly improve the therapeutic efficacy of BCG lysates through the addition of tumor antigens and the use of a hydrogel-based delivery platform.

CD93 blockade promotes effector T-cell infiltration and facilitates adoptive cell therapy in solid tumors

BackgroundAdaptive cellular therapy (ACT), particularly chimeric antigen receptor (CAR)-T cell therapy, has been successful in the treatment of hemopoietic malignancies. However, poor trafficking of administered effector T cells to the...

Thiazole-fused androstenone and ethisterone derivatives: potent β- and γ-actin cytoskeleton inhibitors to treat melanoma tumors.

Melanoma, the most fatal form of skin cancer, often becomes resistant to the current therapeutic approaches in most patients. To explore new treatment options, fused thiazole derivatives were synthesized, and several of these compounds demonstrated potent anti-melanoma activity both in vitro and in vivo. These compounds exhibited significant cytotoxicity against melanoma cell lines at low concentrations. The lead molecules induced apoptosis and caused G2/M phase cell cycle arrest to a lesser extent. These compounds also displayed remarkable antimetastatic activities in several cell-based and molecular assays, significantly inhibiting key processes of metastasis, such as cell migration and adhesion. mRNA sequencing revealed significant downregulation of β-actin (ACTB) and γ-actin (ACTG1) at the transcriptional level, and a similar effect was observed at the protein level by western immunoblotting and proteomics assays. Actin-rich membrane protrusions formation is crucial for facilitating metastasis by promoting cell migration. Fluorescence microscopy demonstrated that compounds E28 and E47 inhibited the formation of these membrane protrusions and impaired actin cytoskeleton dynamics. Docking studies suggested the lead compounds may suppress tumor proliferation and metastasis by targeting the mechanistic target of Rapamycin complex 2 (mTORC2). All these findings unanimously indicated the translational perspective of ethisterone and androstenone fused thiazole derivatives as potent antimetastatic and antimelanoma agents. In a preclinical mouse melanoma model, compounds E2 and E47 significantly reduced tumor growth and greatly improved overall mice survival, while showing a favorable safety profile based on a comprehensive blood plasma metabolite profile. These lead molecules also displayed promising physicochemical properties, making them strong candidates for further drug development studies.

Engineered Perfluorochemical Cancer-Derived Exosomes Loaded with Indocyanine Green and Camptothecin Provide Targeted Photochemotherapy for Effective Cancer Treatment.

Cancer treatments are still limited by various challenges, such as off-target drug delivery, posttreatment inflammation, and the hypoxic conditions in the tumor microenvironment; thus, the development of effective therapeutics remains highly desirable. Exosomes are extracellular vesicles with a size of 30-200 nm that have been widely applied as drug carriers over the last decade. In this study, melanoma-derived exosomes were used to develop a perfluorocarbon (PFC) drug nanocarriers loaded with indocyanine green (ICG) and camptothecin (CPT) (ICFESs) for targeted cancer photochemotherapy. The ICFESs were fabricated by emulsification approach and characterized through instrumental detection. The capabilities of the ICFESs on tumor targeting, intratumoral retention, and cancer photochemotherapy were evaluated using melanoma tumor-bearing mice in association with histological studies and serum marker analyses. ICFESs can be rapidly internalized by homologous melanoma cells, induce hyperthermia and increase the yield of singlet oxygen upon exposure to near-infrared (NIR) irradiation. After 5 min of NIR exposure and 24h of in vitro culture, ICFESs encapsulating ≥ 10/10μM [ICG]/[CPT] effectively killed more than 70% of the cancer cells, inducing greater mortality than that caused by a 4-fold higher dose of CPT alone. In a murine melanoma model, we demonstrated that ICFESs indeed targeted homologous tumors with prolonged intratumoral retention compared with free ICG in vivo. Moreover, tumor growth was significantly arrested by ICFESs containing 40/40μM [ICG]/[CPT] in combination with 30 sec of NIR exposure without systemic toxicity, and the resulting tumors were approximately 15-fold smaller than those treated for 14 days with 40μM free CPT alone. We suggest that the aforementioned anticancer efficacy was achieved via a dual-stage mechanism, phototherapy followed by chemotherapy. Taken together, the developed ICFESs are anticipated to be highly applicable for clinical cancer treatment.

Melanoma cells adhesive properties activation in 3d spheroids

In this study, the viability and adhesive features of BRO and SK-MEL-2 cell lines were evaluated using a melanoma model. It was revealed that in BRO cells, the development of apoptosis after exposure to dacarbazine was combined with the transition of the proportion of cells to the G0 phase of the cell cycle, that corresponded to previously obtained results. The absence of apoptosis in 3D spheroids and the absence of exit from the cell cycle were observed in SK-MEL-2 melanoma cells. It was also revealed that in the control spheroids (cells without exposure) of the BRO and SK-MEL-2 melanoma lines, adhesion to fibronectin was higher compared with the cells of the control monolayer, which is explained by the three-dimensional structure requiring cell communication with the extracellular matrix. In spheroids formed by SK-MEL-2 cells, dacarbazine induced a decrease in adhesion to fibronectin, which may be associated with the development of drug resistance. An increase in the expression of integrins AV and β8 in BRO and SK-MEL-2, as well as integrin β5 in SK-MEL-2, was determined in cells after exposure to dacarbazine, which may indicate the involvement of aforementioned molecules in the exit from proliferative stage of tumor cells.

Neoantigen-Displaying Protein Nanoparticles as a Therapeutic Cancer Vaccine Against Melanoma.

Although interest in peptide-based cancer vaccines has surged in the era of personalized immunotherapy enabled by the discovery of neoantigens, the effective generation of neoantigen-specific T cell responses has been limited. Here, a Brucella BP26 protein-based nanoparticle displaying the MHC class II-restricted melanoma neoantigen, M30, is reported for use as a therapeutic cancer vaccine. Genetic engineering of 10 tandem repeats of the M30 neoepitope to a BP26 monomer results in the self-assembled, neoantigen-displaying protein nanoparticles (BP26-M30 NPs). Subcutaneous immunization of mice with BP26-M30 NPs/CpG adjuvant leads to the activation and maturation of antigen-presenting cells in draining local lymph nodes and elicits M30-specific CD4+ T cell immune responses and immunological memory. In a mouse model of aggressive B16-F10 melanoma, immunization with BP26-M30 NPs/CpG significantly inhibits the growth of established tumors. These findings suggest that the BP26-based self-assembled protein nanoparticle has the potential to be used as a cancer vaccine platform for personalized cancer immunotherapy.

<i>In vivo</i> antitumor effects of bis-benzimidazole derivatives in mouse melanoma and lung cancer models

BACKGROUND: The development of new antitumor agents on the basis of benzimidazoles opens new opportunities for treatment of the malignant tumors, including those refractory to conventional therapies. The benzimidazole derivatives demonstrate wide spectrum of biological activities, specifically antineoplastic effects, and high-level cytotoxicity toward human’s tumor cell lines. The exploration of antineoplastic effects of new synthetic benzimidazole derivatives in in vivo models of tumor growth will help the development of the effective doses and cancer treatment regimens with the use of such compounds. AIM: To assess the antineoplastic effects of the benzimidazole derivatives — monomeric compound MB2Py(Ac) and dimeric compound DB2Py(3) — in the continuous cellular models of Lewis lung carcinoma (LLC) and melanoma B16 in mice. MATERIALS AND METHODS: In vivo assessment of antineoplastic effects was performed in the continuous mouse models of Lewis lung carcinoma (LLC) and B16 melanoma after a single intravenous injection of MB2Py(Ac) and DB2Py(3). Irinotecan was used as a comparator drug. Antitumor effects were measured via standard parameters, such as tumor growth inhibition (TGI%) and tumor growth rate (TGR). RESULTS: The study compounds DB2Py(3) and MB2Py(Ac) used in the study doses and regimen demonstrated mild antitumor effect in the model of murine solid tumors (TGI 50%). In melanoma B16 model, the maximum tumor growth inhibition was 15% and 38.5%, respectively, for MB2Py(Ac) and DB2Py(3). In the lung carcinoma model, the mild effect was observed, e.g. 8% for MB2Py(Ac) and 23.4% for DB2Py(3). The effect of the comparator drug, irinotecan, was more expressive, although short-term. In particular, TGI achieved 52.5% for melanoma B16 and 34.5% for Lewis lung carcinoma (LLC). In general, melanoma B16 was more sensitive to the effects of both bis-benzimidazoles and irinotecan, compared to the lung carcinoma LLC. CONCLUSION: This study shows that the dimeric compound DB2Py(3) was the most promising among three study substances in the models of melanoma and lung carcinoma in mice. Nevertheless, its high toxicity imposes the necessity of further optimization for the clinical use. The substance MB2Py(Ac) demonstrated lowest efficacy, although it may be also explored in the modified treatment regimens.

A human-like glutaminase-free asparaginase is highly efficacious in ASNSlow leukemia and solid cancer mouse xenograft models.

L-asparaginase (L-ASNase) is crucial in treating pediatric acute lymphoblastic leukemia (ALL), but its use is hampered by side effects from the immunogenicity and L-glutaminase (L-GLNase) co-activity of FDA-approved bacterial L-ASNases, often leading to treatment discontinuation and poor outcomes. The toxicity of these L-ASNases makes them especially challenging to use in adult cancer patients. To overcome these issues, we developed EBD-200, a humanized guinea pig L-ASNase with low Km and no L-GLNase activity, eliminating glutamine-related toxicity. EBD-200 showed comparable anti-cancer effects to PEGylated L-ASNase in ASNSlow ALL, melanoma and liver cancer models, with improved tolerability. Its potent anti-cancer efficacy and enhanced safety profile suggest that EBD-200 could benefit ALL patients and broaden treatment options for ASNSlow solid cancers.

Efficacy of CTLA-4 checkpoint therapy is dependent on IL-21 signaling to mediate cytotoxic reprogramming of PD-1+CD8+ T cells.

The mechanisms underlying the efficacy of anti-programmed cell death protein 1 (PD-1) and anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) therapy are incompletely understood. Here, by immune profiling responding PD-1+CD8+ T (TResp) cell populations from patients with advanced melanoma, we identified differential programming of TResp cells in response to combination therapy, from an exhausted toward a more cytotoxic effector program. This effect does not occur with anti-PD-1 monotherapy. Single-cell transcriptome and T cell receptor repertoire analysis was used to identify altered effector programming of expanding PD-1+CD8+ T cell clones with distinct regulon usage, STAT1 and STAT3 utilization and antitumor specificity connected to interleukin (IL)-21 signaling in combination and anti-CTLA-4 monotherapy. Therapeutic efficacy of CTLA-4 blockade was lost in B16F10 melanoma models with either Il21r- deficiency or anti-IL-21 receptor blockade. Together, these results show how IL-21 signaling to TResp is critical for anti-CTLA-4-based checkpoint therapies and highlight major signaling differences to anti-PD-1 monotherapy.

Preparation of a сloso-Dodecaborate Anion Conjugate with Ethyl Glycinate and Study of Its Biodistribution in a B16f10 Melanoma Model

Preparation of a сloso-Dodecaborate Anion Conjugate with Ethyl Glycinate and Study of Its Biodistribution in a B16f10 Melanoma Model

Cancer immunotherapy response persists after lymph node resection.

Lymphatic transport facilitates the presentation of cancer antigens in tumor-draining lymph nodes (tdLNs), leading to T cell activation and the generation of systemic antitumor immune surveillance. Surgical removal of LNs to control cancer progression is routine in clinical practice. However, whether removing tdLNs impairs immune checkpoint blockade (ICB) is still controversial. Our analysis demonstrates that melanoma patients remain responsive to PD-1 checkpoint blockade after LN dissection. We were able to recapitulate the persistent response to ICB after complete LN resection in murine melanoma and mammary carcinoma models. Mechanistically, soluble antigen and antigen-carrying migratory dendritic cells are diverted to non-directly tumor draining LNs (non-tdLNs) after tdLN dissection. Consistently, robust ICB responses in patients with head and neck cancer after primary tumor and tdLN resection correlated with the presence of reactive LNs in distant areas. These findings indicate that non-tdLNs sufficiently compensate for the removal of direct tdLNs and sustain the response to ICB.

Transient EZH2 suppression by Tazemetostat during in vitro expansion maintains T-cell stemness and improves adoptive T-cell therapy.

The histone methyltransferase enhancer of zeste homolog 2 (EZH2) plays important roles in T-cell differentiation, proliferation and function. Previous studies have demonstrated that genetic deletion of EZH2 in CD8+ or total T cells impairs their antiviral and antitumor activity, cytokine production and ability to expand upon rechallenge. Contrary to the detrimental role of deleting T cell-intrinsic EZH2, here we have demonstrated that transient inhibition of EZH2 in T cells prior to the phenotypic onset of exhaustion with a clinically approved inhibitor, Tazemetostat, delayed their dysfunctional progression and preserved T-cell stemness and polyfunctionality but had no negative impact on cell proliferation. Tazemetostat induced T-cell epigenetic reprogramming and increased the expression of the self-renewal T-cell transcription factor TCF1 by reducing H3K27 methylation at its promoter preferentially in rapidly dividing T cells. In a murine melanoma model, T cells depleted of EZH2 induced poor tumor control, whereas adoptively transferred T cells pretreated with tazemetostat exhibited superior antitumor immunity, especially when used in combination with anti-PD-1 blockade. Collectively, these data highlight the potential of transient epigenetic reprogramming by EZH2 inhibition to enhance adoptive T-cell immunotherapy.