Long-term results with nivolumab and ipilimumab in melanoma
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Nivolumab plus chemotherapy or ipilimumab in gastroesophageal cancer: exploratory biomarker analyses of a randomized phase 3 trial
First-line nivolumab-plus-chemotherapy demonstrated superior overall survival (OS) and progression-free survival versus chemotherapy for advanced gastroesophageal adenocarcinoma with programmed death ligand 1 combined positive score ≥ 5, meeting both primary end points of the randomized phase 3 CheckMate 649 trial. Nivolumab-plus-ipilimumab provided durable responses and higher survival rates versus chemotherapy; however, the prespecified OS significance boundary was not met. To identify biomarkers predictive of differential efficacy outcomes, post hoc exploratory analyses were performed using whole-exome sequencing and RNA sequencing. Nivolumab-based therapies demonstrated improved efficacy versus chemotherapy in hypermutated and, to a lesser degree, Epstein–Barr virus-positive tumors compared with chromosomally unstable and genomically stable tumors. Within the KRAS-altered subgroup, only patients treated with nivolumab-plus-chemotherapy demonstrated improved OS benefit versus chemotherapy. Low stroma gene expression signature scores were associated with OS benefit with nivolumab-based regimens; high regulatory T cell signatures were associated with OS benefit only with nivolumab-plus-ipilimumab. Our analyses suggest that distinct and overlapping pathways contribute to the efficacy of nivolumab-based regimens in gastroesophageal adenocarcinoma.
Human CSPG4-targeting CAR-macrophages inhibit melanoma growth
Approximately half of melanoma patients relapse or fail to respond to current standards of care, highlighting the need for new treatment options. Engineering T-cells with chimeric antigen receptors (CARs) has revolutionized the treatment of hematological malignancies but has been clinically less effective in solid tumors. We therefore sought to engineer alternative immune cell types to inhibit melanoma progression. Engineering macrophages with CARs has emerged as a promising approach to overcome some of the challenges faced by CAR-T cells; however, whether these engineered macrophages can effectively inhibit melanoma growth is unknown. To determine whether CAR-macrophages (CAR-Ms) specifically target and kill melanoma cells, we engineered CAR-Ms targeting chondroitin sulfate proteoglycan 4 (CSPG4), an antigen expressed in melanoma. CSPG4-targeting CAR-Ms exhibited specific phagocytosis of CSPG4-expressing melanoma cells. We developed 3D approaches to show that CSPG4-targeting CAR-Ms efficiently infiltrated melanoma spheroids. Furthermore, combining CSPG4-targeting CAR-Ms with strategies inhibiting CD47/SIRPα “don’t eat me” signaling synergistically enhanced CAR-M-mediated phagocytosis and robustly inhibited melanoma spheroid growth in 3D. Importantly, CSPG4-targeting CAR-Ms inhibited melanoma tumor growth in mouse models. These results suggest engineering macrophages against melanoma antigens is a promising solid tumor immunotherapy approach for treating melanoma.
Melanoma bone metastasis-induced osteocyte ferroptosis via the HIF1α-HMOX1 axis
Osteocytes are the main cells in mineralized bone tissue. Elevated osteocyte apoptosis has been observed in lytic bone lesions of patients with multiple myeloma. However, their precise contribution to bone metastasis remains unclear. Here, we investigated the pathogenic mechanisms driving melanoma-induced osteocyte death. Both in vivo models and in vitro assays were combined with untargeted RNA sequencing approaches to explore the pathways governing melanoma-induced osteocyte death. We could show that ferroptosis is the primary mechanism behind osteocyte death in the context of melanoma bone metastasis. HMOX1 was identified as a crucial regulatory factor in this process, directly involved in inducing ferroptosis and affecting osteocyte viability. We uncover a non-canonical pathway that involves excessive autophagy-mediated ferritin degradation, highlighting the complex relationship between autophagy and ferroptosis in melanoma-induced osteocyte death. In addition, HIF1α pathway was shown as an upstream regulator, providing a potential target for modulating HMOX1 expression and influencing autophagy-dependent ferroptosis. In conclusion, our study provides insight into the pathogenic mechanisms of osteocyte death induced by melanoma bone metastasis, with a specific focus on ferroptosis and its regulation. This would enhance our comprehension of melanoma-induced osteocyte death.
The anti-melanoma roles and mechanisms of tricholoma isoflavone derivative CA028
As a form of skin cancer, melanoma’s incidence rate is continuing to rise globally. Therefore, there is an urgent need to find new agents to improve survival in melanoma patients. Isoflavones, a class of phytoestrogens, are primarily found in soy and other legumes. Cumulating evidence demonstrates that isoflavones exhibits significant anti-tumor properties and is beneficial for the prevention and treatment of melanoma. In the present study, we aim to investigate the anti-melanoma role of tricholoma isoflavone derivative CA028. By using in vitro melanoma cell line models, A375 and A2058 and in vivo xenograft mouse model, our results indicate that melanoma proliferation, migration, and invasion are attenuated following CA028 treatment. In addition, the treatment of CA028 induced cell apoptosis of melanoma. Finally, we addressed the mechanism of CA028 against melanoma by comparative transcriptomic analysis. The results of gene ontology highlighted the involvement of CA028’s targets in the cell proliferation, cell apoptosis, and migration ability of melanoma cells. Furthermore, Ingenuity Pathway Analysis constructed the network involved in the apoptotic roles of CA028 through targeting p53 signaling and death receptor signaling. For the first time, our data suggested the possible use of modified isoflavone for therapeutic applications against melanoma.
Transcriptional reprogramming triggered by neonatal UV radiation or Lkb1 loss prevents BRAFV600E-induced growth arrest in melanocytes
The mechanisms behind UVB-initiated, neonatal-specific melanoma linked to BRAFV600E are not well understood, particularly regarding its role in growth arrest. We found that, beyond mutations, neonatal UV irradiation or Lkb1 loss promotes a cell-autonomous transcriptional reprogramming that prevents BRAFV600E-induced growth arrest, leading to melanoma development. Using UVB-dependent and independent mouse models, genomic analyses, clinical data, and single-cell transcriptomics, we identified a transcriptional program that bypasses growth arrest, promoting melanoma. In humans, many of these genes are linked to poor survival and are upregulated in melanoma progression and other RAS pathway-driven tumors. Reconstitution experiments showed these genes cooperate with BRAFV600E in melanocyte transformation, dedifferentiation, and drug resistance. Depleting gene products like UPP1 highlights their potential as therapeutic targets. Our findings reveal that BRAFV600E-mutated melanomas can develop independently of nevus progression and identify novel targets for treatment.
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