A decade of checkpoint blockade immunotherapy in melanoma: understanding the molecular basis for immune sensitivity and resistance

Gut microbiota in melanoma: Effects and pathogeneses

The gut microbiota exhibits intricate connections with the body's immune system and holds significant implications for various diseases and cancers. Currently, accumulating evidence suggests a correlation between the composition of the gut microbiota and the development, treatment, and prognosis of melanoma. However, the underlying pathogenesis remains incompletely elucidated. In this comprehensive review, we present an in-depth review of the role played by gut microbiota in melanoma tumorigenesis, growth, metastasis, treatment response, and prognosis. Furthermore, we discuss the potential utility of gut microbiota as a promising prognostic marker. Lastly, we summarize three routes through which gut microbiota influences melanoma: immunity, aging, and the endocrine system. By modulating innate and adaptive immunity in patients with melanoma across different age groups and genders, the gut microbiota plays a crucial role in anti-tumor immune regulation from tumorigenesis to prognosis management, thereby impacting tumor growth and metastasis. This review also addresses current study limitations while highlighting future research prospects.

Neospora caninum as delivery vehicle for anti-PD-L1 scFv-Fc: A novel approach for cancer immunotherapy

Neospora caninum, a potential anticancer agent able to reactivate the immune response within the tumor microenvironment (TME), has recently shown enhanced immunomodulatory properties in different tumor models when armed with the cytokine, Il-15. In the current area of combination immunotherapy strategies designed to overcome treatment resistance, we engineered for the first time the protozoan Neospora caninum to vectorize and secrete a single-chain variable fragment fused to fragment crystallizable region (scFv-Fc) targeting human programmed cell death ligand 1 (PD-L1). Following validation of its secretion through the micronemes (protozoa secretory organelles), we demonstrated that the scFv-Fc could bind PD-L1 on mouse and human tumor cells, block the programmed cell death protein 1 (PD-1)/PD-L1 pathway leading to potentiate the T cell lymphocyte activity. Additionally, the scFv-Fc induced antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent cellular cytotoxicity (ADCC). Those data demonstrate the feasibility of vectoring and secreting a functional antibody fragment by N. caninum, opening promising avenues for future research.

Co-encapsulated Ce6 + CpG and biopeptide-modified liposomes for enhanced transdermal photo-immunotherapy of superficial tumors

Cancer immunotherapy encounters challenges of a low treatment response rate due to the tumor immunosuppressive microenvironment and immune-related adverse events caused by off-target immunotherapy agents delivered through systemic administration in clinical practice. Photodynamic therapy (PDT) offers a viable approach to improve the immunotherapy efficacy through inducing immunogenic tumor cell death and is particularly advantageous in superficial tumor treatment. Therefore, leveraging integrated nanomaterials for photo-immunotherapy appears to be an ideal strategy to improve therapeutic outcome. In this study, we develop a transdermal-enhancing peptide (TD)-modified cationic liposome that simultaneously encapsulated with photosensitizer chlorine 6 (Ce6) and immunoadjuvant CpG, denoted as Ce6/CpG@Lip-TD, to mediate photo-immunotherapy of superficial tumors via the skin. The functionalization of TD peptide and positively charged surface endow the liposomes enhanced skin penetration capability. The combination of Ce6 and CpG within the liposomes synergistically potentiates the photo-immunotherapy effect when exposed to laser irradiation. In both melanoma and breast cancer murine models, Ce6/CpG@Lip-TD demonstrated substantial tumor-suppressing properties, along with an augmented systemic immune response against distal tumors. As a topical therapeutic agent, Ce6/CpG@Lip-TD circumvents the regulatory challenges associated with the systemic delivery of nanomaterials and significantly reduces systemic side effects, holding great promise for rapid translation into clinical applications.

Unlocking the power of immune checkpoint inhibitors: Targeting YAP1 reduces anti-PD1 resistance in skin cutaneous melanoma

BACKGROUND AND PURPOSE

Immune checkpoint inhibitors, such as anti-PD1, revolutionized melanoma treatment. However, resistance and low response rates remain problems. Our goal was to pinpoint actionable biomarkers of resistance to anti-PD1 treatment and verify therapeutic effectiveness in vivo.

EXPERIMENTAL APPROACH

Using receiver operating characteristic (ROC) and survival analysis in a database of 1434 samples, we identified the strongest resistance-associated genes. Inhibitors were evaluated in C57BL/6J mice using wild-type B16-F10, and BRAF, -PTEN, -CDKN2A-mutant YUMM1.7 melanoma cell lines. We investigated the synergistic impact of anti-PD1 therapy and yes-associated protein 1 (YAP1) inhibition by non-photoactivated Verteporfin. Tumour volume was determined at fixed cutoff points, normalized to body weights.

KEY RESULTS

In the anti-PD1-treated melanoma cohort, YAP1 was the strongest druggable candidate overexpressed in non-responder patients (ROC AUC = 0.699, FC = 1.8, P=1.1E-8). The baseline YAP1 expression correlated with worse progression-free survival (HR = 2.51, P=1.2E-6, FDR = 1%), and overall survival (HR = 2.15, P = 1.2E-5, FDR = 1%). In YUMM1.7, combination of Verteporfin plus anti-PD1 reduced tumour size more than anti-PD1 monotherapy (P=0.008), or control (P=0.021). There was no difference between the cohorts in B16-F10 inoculated mice. We found increased expression of YAP1 in YUMM1.7 mice compared to B16-F10. The combination therapy induced a more-immune-inflamed phenotype characterized by increased expression of T cell and M1 macrophage markers.

CONCLUSIONS AND IMPLICATIONS

Verteporfin with anti-PD1 exhibited antitumor potential by promoting a pro-inflammatory tumour microenvironment in melanoma. We believe that YAP1 acts as a master regulator of anti-PD1 resistance.

Emerging importance of HER3 in tumorigenesis and cancer therapy

HER3 is a member of the HER/ErbB family of receptor tyrosine kinases, together with EGFR (HER1), HER2 and HER4. Despite having only weak intrinsic kinase activity, HER3 can contribute to oncogenic signalling via ligand-induced heterodimerization with other HER family members. Evidence indicates that HER3 is altered or aberrantly expressed across a variety of tumour types and can be associated with poor clinical outcomes. Whereas anticancer agents targeting EGFR and HER2 have been approved for decades, no drug targeting HER3 had been approved until very recently. Initial targeting of HER3 with monoclonal antibodies as single agents or in combination with other therapeutics produced disappointing clinical results. Subsequently, efforts have been made to target HER3 with novel agents such as antibody-drug conjugates and bispecific antibodies, with promising efficacy observed in several trials encompassing various tumour types. In December 2024, the HER3 × HER2 bispecific antibody zenocutuzumab was granted FDA Accelerated Approval for the treatment of non-small-cell lung cancers or pancreatic cancers harbouring fusions involving NRG1, the gene encoding the high-affinity HER3 ligand neuregulin 1. In this Review, we provide an essential guide to HER3 signalling and oncogenesis, HER3 expression in cancer and its prognostic implications, oncogenic HER3 somatic mutations as well as rare NRG1 fusions that might depend on HER3 signalling, and the roles of HER3 in resistance to cancer therapies. We also highlight efforts to target HER3 with diverse therapeutic strategies and the potential interplay between HER3 and the antitumour immune response.

Oral Melanoma in Older Adults: Epidemiology, Molecular Landscape, and Treatment Strategies

Oral melanoma is an aggressive neoplasm arising from melanocytes in the mucosal epithelium, accounting for 0.2%-0.8% of all melanomas. Unlike cutaneous melanoma, it is not associated with UV exposure, and its pathogenesis involves complex genetic and molecular alterations. This neoplasm predominantly affects older adults (≥ 60 years). Clinically, lesions often present as macular or nodular with an exophytic growth pattern, sometimes ulcerated, and exhibit varied pigmentation. Diagnosis is further complicated by non-pigmented (amelanotic) variants that can resemble other oral pigmentations. Wide surgical excision remains the mainstay treatment, often combined with chemotherapy; however, recurrence and distant metastasis remain high. While immunotherapy has shown promise in other melanoma subtypes, its efficacy in oral melanoma remains uncertain. Treatment in older adults is particularly challenging due to comorbidities and treatment-related morbidity. This review summarizes the epidemiology, clinical features, and current treatment strategies for oral melanoma in older adults. Key advances in the molecular mechanisms underlying this neoplasm are also outlined. As a strategic approach, integrating oral melanoma screening into routine geriatric dental care, supported by diagnostic algorithms, may improve early detection, prognosis, and survival outcomes in this vulnerable population.

Management of metastatic melanoma with combinations including PD-1 inhibitors

INTRODUCTION

Melanoma is among the most immunogenic malignancies. The advent of immune checkpoint inhibitors (ICIs) has revolutionized the landscape of melanoma treatment. Long-term durable cancer control is possible in nearly 50% of non-resectable, metastatic melanoma patients with anti-CTLA4 and anti-PD-1 antibodies.

AREAS COVERED

This review provides a critical overview of the current data and future research directions on the management of metastatic melanoma with ICIs. We reviewed the efficacy and safety of combinations with PD-1 inhibitors through PubMed database research (Nov 2024-Mar 2025).

EXPERT OPINION

A decade after ipilimumab's approval, challenges remain. To cure more patients, the development of combinations is warranted. Combinations with a limited number of ipilimumab applications improve the overall survival outcome by approximately 10%, with a dramatic increase in adverse events including fatal events. Anti-LAG3/nivolumab is a promising alternative, offering similar efficacy to ipilimumab/nivolumab with better tolerability. In our opinion, ipilimumab/nivolumab combination should be the first-line therapy for high-risk patients (high LDH, brain or liver metastasis), while nivolumab/relatlimab or PD-1 monotherapy may be preferable for lower-risk cases. However, treatment decisions are increasingly complex, since most patients nowadays are pretreated in the (neo)-adjuvant setting. The key limitation today is the lack of biomarkers to guide individualized treatment strategies.

Mechanistic insights into proteasome inhibitor MG132 induced apoptosis in melanoma A375 cells

Despite advancements in melanoma therapy, the prognosis remains unfavorable for many patients. The proteasome inhibitor MG132 has shown therapeutic potential through pathway regulation, yet its precise mechanisms in melanoma require systematic elucidation. Using A375 melanoma cells, we conducted multi-modal investigations combining cytotoxicity assessment (CCK8), migration analysis (wound healing), apoptosis quantification (flow cytometry), and proteomic profiling (western blot) to dissect MG132's molecular mechanisms. Our findings revealed MG132's potent anti-tumor activity with an IC50 of 1.258 ± 0.06 µM, significantly suppressing cellular migration at therapeutic concentrations. Apoptosis assays demonstrated concentration-dependent effects, with 2 µM treatment inducing early apoptosis in 46.5% and total apoptotic response in 85.5% of cells within 24 h. Mechanistic studies uncovered MG132's dual regulatory capacity: (1) Through MDM2 inhibition, it activated p53/p21/caspase-3 axis while suppressing CDK2/Bcl2, triggering cell cycle arrest and DNA damage cascades; (2) MAPK pathway activation emerged as a critical apoptosis driver. Notably, western blot analysis established dose-responsive modulation of these molecular targets, confirming pathway specificity. Our results position MG132 as a multi-target agent capable of simultaneously disrupting proliferative signaling and activating apoptotic machinery. The observed MAPK-mediated apoptosis mechanism provides novel insights for melanoma therapeutics, suggesting that combinatorial targeting of proteasomal and MAPK pathways may enhance treatment efficacy.

Noninvasive Transdermal Delivery of STING Agonists Reshapes the Immune Microenvironment of Melanoma and Potentiates Checkpoint Blockade Therapy Efficacy

The emergence of immunotherapy as a revolutionary therapeutic modality has fostered confidence and underscored its potent efficacy in tumor therapy. However, enhancing the therapeutic efficacy of immunotherapy by precise and judicious administration poses a significant challenge. In this context, we have developed a disulfide-bearing transdermal nanovaccine by integrating a thiol-reactive agent lipoic acid (LA) into a metal-coordinated cyclic dinucleotide nanoassembly, designated as LA-Mn-cGAMP (LMC) nanovaccines. Upon topical application to the skin with melanoma, the dithiolane moiety of LA enables thiol-disulfide dynamic exchange in the skin, hence facilitating penetration into both the skin and subcutaneous tumor tissues via the thiol-mediated uptake (TMU) mechanism. Our findings demonstrate that transdermal administration of LMC significantly enhances STING activation, mitigates the immunosuppressive tumor microenvironment (TME), and retards melanoma progression. Moreover, the remodeled TME amplifies the efficacy of immune checkpoint inhibitors. This advancement offers an administration strategy for existing STING agonist therapy, potentially improving the biosafety of immunotherapy.

Deconvolution of cell types and states in spatial multiomics utilizing TACIT

Identifying cell types and states remains a time-consuming, error-prone challenge for spatial biology. While deep learning increasingly plays a role, it is difficult to generalize due to variability at the level of cells, neighborhoods, and niches in health and disease. To address this, we develop TACIT, an unsupervised algorithm for cell annotation using predefined signatures that operates without training data. TACIT uses unbiased thresholding to distinguish positive cells from background, focusing on relevant markers to identify ambiguous cells in multiomic assays. Using five datasets (5,000,000 cells; 51 cell types) from three niches (brain, intestine, gland), TACIT outperforms existing unsupervised methods in accuracy and scalability. Integrating TACIT-identified cell types reveals new phenotypes in two inflammatory gland diseases. Finally, using combined spatial transcriptomics and proteomics, we discover under- and overrepresented immune cell types and states in regions of interest, suggesting multimodality is essential for translating spatial biology to clinical applications.

Exosomes as key mediators in immune and cancer cell interactions: insights in melanoma progression and therapy

Exosomes (30-150 nm) are small extracellular vesicles that are secreted by cells into the extracellular environment and are known to mediate cell-to-cell communication. Exosomes contain proteins, lipids, and RNA molecules in relative abundance, capable of modifying the activity of target cells. Melanoma-derived exosomes (MEXs) promote the transfer of oncogenic signals and immunosuppressive factors into immune cells, resulting in a bias of the immune response towards tumor-promoting processes. MEXs could suppress the activation and proliferation of T cells and dendritic cells and induce differentiation of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). They can induce apoptosis of antigen-specific CD8 + T cells and promote the transfer of tumor antigens, resulting in immune evasion. Specifically, MEXs can shuttle cytokines like interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) to immune cells or express programmed death-ligand 1 (PD-L1 or CD274), creating an immune-suppressive microenvironment that promotes tumorigenesis. Since exosomes preferentially accumulate in melanoma tissues, this targeted delivery could enhance the bioavailability of treatments while limiting side effects. Here, we review the molecular composition of melanoma-derived exosomes, their mechanisms of action, and their potential as therapeutic targets or biomarkers in melanoma. The summarizations of these mechanisms to appropriately influence exosome-mediated interactions could yield new tactics to elicit anti-melanoma immunity or augment the therapeutic effects of current therapies.

Overcoming extracellular vesicle-mediated fratricide improves CAR T cell treatment against solid tumors

The efficacy of chimeric antigen receptor (CAR) T cells against solid tumors is limited. The molecular mechanisms underlying CAR T cell resistance are yet to be elucidated and new strategies need to be developed to improve treatment outcomes. Here we report that solid tumors respond to CAR T cells by upregulating the secretion of small extracellular vesicles carrying tumor antigens, which are horizontally transferred to CAR T cells, leading to antigen recognition and CAR T cell fratricide. Engineered CAR T cells armored with Serpin B9, a major granzyme B inhibitor, show decreased fratricide and increased vitality, tumor infiltration, and antitumor activity in female mice. Moreover, Serpin B9-armored CAR T cells show higher efficacy than parental CAR T cells in treating solid tumors when combined with the anti-programmed death 1 antibody. Our study demonstrates a mechanism that limits CAR T cell function and suggests an improved strategy in tumor treatment.

Immune microenvironment of tumor-draining lymph nodes: insights for immunotherapy

Tumor-draining lymph nodes (TDLNs) play a crucial role in modulating tumor immune responses and influencing the efficacy of immunotherapy. However, our current understanding of the microenvironment within these lymph nodes remains limited. Tumors not only impair the anti-tumor activity of CD8+ T cells by creating an immunosuppressive microenvironment, but they also facilitate immune evasion and promote metastasis by altering the structure and function of TDLNs. Research has shown that tumor-specific memory CD8+ T cells (TTSM) within TDLNs are essential for the efficacy of immune checkpoint inhibitors, such as PD-1/PD-L1 blockers. Moreover, the abnormal structure of TDLNs, along with the presence of immunosuppressive cells-such as regulatory T cells (Tregs), regulatory B cells (Bregs), and immunosuppressive dendritic cells (DCs)-contributes to tumor-mediated immune evasion. Therefore, gaining a deeper understanding of the immune microenvironment within TDLNs is essential for improving the effectiveness of immunotherapies and developing novel therapeutic strategies. This review explores various TDLN-based therapeutic strategies, addressing the controversies surrounding lymph node dissection, the use of TDLNs as a source of tumor-infiltrating lymphocytes (TILs) for therapy, targeting immunosuppressive cells within TDLNs, and methods to reverse the structural abnormalities of TDLNs. These strategies offer valuable insights and potential directions for advancing tumor immunotherapy.

Identifying predictors of overall survival among patients with TMB-low metastatic cancer treated with immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) have significantly advanced cancer therapy, yet their efficacy in tumors with low tumor mutational burden (TMB) remains suboptimal. In this study, we aimed to elucidate the impact of somatic mutations on overall survival (OS) in TMB-low patients treated with ICIs and to explore the potential for personalized treatment selection through machine learning.

METHODS

We conducted a comprehensive analysis of 1172 TMB-low (TMB < 10 mutations per megabase) patients with cancer receiving ICIs, examining the association between specific gene mutations and OS. Additionally, we developed a decision tree model (DTM) to predict OS based on clinical features and tumor mutational profiles.

RESULTS

Our findings reveal that mutations in DAXX, HLA-A, H3C2, IGF1R, CTNNB1, SMARCA4, KMT2D, and TP53 are significantly associated with poorer survival outcomes in the multivariate analysis. Remarkably, for renal cell carcinoma (RCC) patients, VHL mutations predicted improved OS following ICI even when adjusted for age, sex, and microsatellite instability (MSI) status in both multivariate analysis and the DTM model.

CONCLUSIONS

These results reinforce the prevailing notion that TMB alone does not predict ICI response, highlighting the critical role of individual gene mutations in TMB-low tumors under ICI therapy. Furthermore, our study demonstrates the promise of machine learning models in optimizing ICI treatment decisions, paving the way for more precise and effective therapeutic strategies in this patient population.

Deubiquitination by USP7 Stabilizes JunD and Activates AIFM2 (FSP1) to Inhibit Ferroptosis in Melanoma

Ferroptosis resistance in melanoma cells is a key factor in melanoma progression, influenced by the tumor microenvironment. This study investigates the regulatory mechanisms of the USP7-JunD-AIFM2 pathway, which contributes to ferroptosis resistance in melanoma cells. We identified USP7 as a critical deubiquitinase that stabilizes the transcription factor JunD. Stabilized JunD, in turn, promotes the expression of AIFM2 (also known as FSP1), enhancing ferroptosis resistance in melanoma. Inhibition of USP7 led to JunD degradation and reduced AIFM2 levels, effectively sensitizing melanoma cells to ferroptosis both in vitro and in murine xenograft models. These findings underscore the role of the USP7-JunD-AIFM2 pathway in ferroptosis resistance and suggest that targeting USP7 could provide a potential therapeutic strategy against resistant melanoma.

Overcoming myeloid-driven resistance to CAR T therapy by targeting SPP1

Chimeric antigen receptor (CAR) T cell therapy faces notable limitations in treatment of solid tumors. The suppressive tumor microenvironment (TME), characterized by complex interactions among immune and stromal cells, is gaining recognition in conferring resistance to CAR T cell therapy. Despite the abundance and diversity of macrophages in the TME, their intricate involvement in modulating responses to CAR T cell therapies remains poorly understood. Here, we conducted single-cell RNA sequencing (scRNA-seq) on tumors from 41 glioma patients undergoing IL13Rα2-targeted CAR T cell therapy, identifying elevated suppressive SPP1 signatures predominantly in macrophages from patients who were resistant to treatment. Further integrative scRNA-seq analysis of high-grade gliomas as well as an interferon-signaling deficient syngeneic mouse model-both resistant to CAR T therapy-demonstrated the role of congruent suppressive pathways in mediating resistance to CAR T cells and a dominant role for SPP1+ macrophages. SPP1 blockade with an anti-SPP1 antibody abrogates the suppressive TME effects and substantially prolongs survival in IFN signaling-deficient and glioma syngeneic mouse models resistant to CAR T cell therapy. These findings illuminate the role of SPP1+ macrophages in fueling a suppressive TME and driving solid tumor resistance to CAR cell therapies. Targeting SPP1 may serve as a universal strategy to reprogram immune dynamics in solid tumors mitigating resistance to CAR T therapies.

Biomarker-informed care for patients with renal cell carcinoma

Kidney cancer is a commonly diagnosed cancer in adults, and clear cell renal cell carcinoma (ccRCC) is the most common histological subtype. Immune checkpoint inhibitors have revolutionized care for patients with ccRCC, either as adjuvant therapy or combined with other agents in advanced disease. However, biomarkers to predict therapeutic benefits are lacking. Here, we explore biomarkers that predict therapeutic response in other tumor types and discuss the reasons for their ineffectiveness in ccRCC. We also review emerging predictive and prognostic biomarkers to prioritize in ccRCC, including gene expression signatures.

Genomic profiles of patients with skin melanoma in the era of immune checkpoint inhibitors

The use of immune checkpoint inhibitors (ICIs) for treating melanoma has dramatically improved patient prognosis. The genomic profiles of patients receiving ICI therapy would provide valuable information for disease management and treatment. We investigated the genomic profiles of patients with melanoma who had received ICI therapy and explored associations with clinical features and outcomes via a large-scale nationwide database in Japan (the C-CAT database). We identified 339 patients eligible for this study. The most frequent genetic mutations were found in the BRAF (27%), TERT (24%), and NRAS (19%) genes, and the most common copy number variations (CNVs) were in the CDKN2A (36%), CDKN2B (26%), and MTAP (19%) genes. Associations with high tumor mutational burden (TMB-high) status were significant for TERT (p < 0.001), NF1 (p < 0.001), ROS1 (p = 0.015), POLE (p = 0.045), and POLD1 (p = 0.008) mutations, along with older age (≥65 years, p = 0.036). Patients with multiple metastases (two or more) were more likely to have NOTCH3 mutations (p = 0.017) and be younger than 65 years (p = 0.024). In particular, as well as younger age, patients with brain metastases were more likely to harbor BRAF mutations (p < 0.001), while those with liver metastases were more likely to harbor NOTCH3 mutations (p < 0.001) but not CDKN2B CNVs (p = 0.041). Patients with NRAS mutations were less likely to respond to ICI therapy (p = 0.014) and exhibited shorter overall survival (p = 0.006). In this population, the frequency of BRAF mutations was lower than that in fair-skinned populations, but the associations between genomic profiles, clinical features, and outcomes were similar to those previously reported in fair-skinned populations.

Modulating tumor immunity using advanced microbiome therapeutics producing an indole metabolite

The gut microbiome has emerged as a key player in modulating immune responses against cancer, suggesting that microbial interventions can enhance treatment outcomes. Indole metabolites produced by probiotic bacteria activate the aryl hydrocarbon receptor (AhR), a transcription factor important for immune cell regulation. Cancer patients with high plasma concentrations of these metabolites have shown improved survival. Building on these findings, we have engineered Escherichia coli Nissle 1917 to produce the AhR agonist indole-3-acetic acid. Delivery of indole-3-acetic acid by tumor-colonizing bacteria changes the tumor microenvironment in a murine model, significantly increasing levels of CXCL9 and IFN-γ and elevating tumor-infiltrating T-cell abundance and activation. Treatment with our engineered strain inhibits tumor growth, improves survival in syngeneic tumor models, and leads to long-lasting immunity in a tumor rechallenge experiment. Further investigation indicates that this immune modulation is driven by the direct activation of AhR by indole-3-acetic acid, leading to differential cytokine expression and a shift in immune cell composition within the tumor. This study highlights the importance of microbial metabolites in immune modulation and supports exploring microbiome-based therapies in oncology.

Transcriptomic signatures in peripheral CD4+T-lymphocytes may reflect melanoma staging and immunotherapy responsiveness prior to ICI initiation

Background and purpose

Promoting adaptive immunity with ICIs has drastically improved melanoma prognosis, but not for all patients. Some cases relapse in the first few months, while others keep durable benefit, even after immunotherapy discontinuation. To identify cellular/molecular signatures in peripheral blood that could differentiate advanced from metastatic melanoma and predict dynamics for primary/secondary immune escape, we examined 100 consecutive patients with stage III/IV melanoma scheduled to start ICIs.

Materials and methods

At melanoma diagnosis, a multiparameter flow cytometric analysis and purification scheme using standard conjugated antibodies were performed for all individuals prior to ICI initiation. In each stage(III/IV) according to their RFS/PFS, we retrospectively selected the cases with the clearest clinical outcomes and focused our analysis on the extreme responders(n=7) and non-responders(n=7) to characterize the transcriptomes of circulating CD4+T-cells by bulk RNA-seq, Differential Expression Analysis(DEA)and Gene Ontology(GO)enrichment analysis. Based on our selected patient cohort, we examined for differentially expressed genes(DEGs)and key-pathways that appear preferentially activated in stage III vs. IV melanoma, and in long vs. short immunotherapy responders.

Results

Although circulating immune-cells did not numerically differ in both sets of analysis(staging and ICI responsiveness), DEA and GO data showed that patients could be clustered separately, identifying 189vs.92 DEGs in stage IV/III and 101vs.47 DEGs in early progressors/long responders. These DEGs were functionally implicated in distinct pathways. For metastatic cases: inflammatory response(logp-value=-9.2:ADGRE5/2,CYBA,GRN,HMOX1,IRF5,ITGAM), adaptive immunity(logp-value=-7.7:CD1C,CD74,CYBB,NCF2,CTSA,S100A8/9,BCL3,FCER1G), T-cell activation(logp-value=-6.3:BCL3,CD1C,CD74,FCER1G,FGL2)and lipid metabolism/catabolism(logp-value=-2.5/-2.6:ARF3,GPX1,MVD,OCRL,PCCB,CTSA,PNPLA2,NAGLU,GBA2,ABHD4); while in early-progressors to ICIs: immune effector processing(logp-value=-13.7:BCL6,FGR,HLA-DQA1/DQB1,HLA-DRA,HLA-DRB1/DRB5,NKG7,SLC11A1,TYROBP,SPON2,HAVCR2),PD-1(logp-value=-10.2:HLA-DQA1/DQB1,HLA-DRA,HLA-DRB1/DRB5)and IFN signaling(logp-value=-8.5: HLA-DQA1/DQB1,HLA-DRA,HLA-DRB1/DRB5,NCAM1,IFITM3),positive regulation of T-cell activation(logp-value=-7.7:BCL6,HLA-DQA1/DQB1,HLA-DRA,HLA-DRB1/DRB5,SASH3,HAVCR2)and CD28 co-stimulation(logp-value=-10.3:HLA-DQA1/DQB1,HLA-DRA,HLA-DRB1/DRB5), supporting an immune-mediated behavior.

Conclusions

Specific pathways and marker genes in the peripheral CD4+T-cells may predetermine melanoma staging and immunotherapy resistance.

Redirecting cytotoxic lymphocytes to breast cancer tumors via metabolite-sensing receptors

Insufficient infiltration of cytotoxic lymphocytes to solid tumors limits the efficacy of immunotherapies and cell therapies. Here, we report a programmable mechanism to mobilize Natural Killer (NK) and T cells to breast cancer tumors by engineering these cells to express orphan and metabolite-sensing G protein-coupled receptors (GPCRs). First, in vivo and in vitro CRISPR activation screens in NK-92 cells identified GPR183, GPR84, GPR34, GPR18, FPR3, and LPAR2 as top enhancers of both tumor infiltration and chemotaxis to breast cancer. These genes equip NK and T cells with the ability to sense and migrate to chemoattracting metabolites such as 7α,25-dihydroxycholesterol and other factors released from breast cancer. Based on Perturb-seq and functional investigations, GPR183 also enhances effector functions, such that engineering NK and CAR NK cells to express GPR183 enhances their ability to migrate to, infiltrate, and control breast cancer tumors. Our study uncovered metabolite-based tumor immune recruitment mechanisms, opening avenues for spatially targeted cell therapies.

Circulating tumor DNA to monitor treatment response in solid tumors and advance precision oncology

Circulating tumor DNA (ctDNA) has emerged as a dynamic biomarker in cancer, as evidenced by its increasing integration into clinical practice. Carrying tumor specific characteristics, ctDNA can be used to inform treatment selection, monitor response, and identify drug resistance. In this review, we provide a comprehensive, up-to-date summary of ctDNA in monitoring treatment response with a focus on lung, colorectal, and breast cancers, and discuss current challenges and future directions.

PD-L1 blockade peptide-functionalized NaGdF4 nanodots for efficient magnetic resonance imaging-guided immunotherapy for breast cancer

Immune checkpoint blockade (ICB) inhibitors have shown great promise for the treatment of numerous types of cancers, including triple-negative breast cancer (TNBC), by interrupting immunosuppressive checkpoints. Herein, programmed cell death ligand 1 (PD-L1) blockade peptide-functionalized NaGdF4 nanodots (designated as PDL1-NaGdF4 NDs) were prepared for magnetic resonance imaging (MRI)-guided TNBC immunotherapy through covalent conjugation of the PD-L1 blockade peptide (sequence, CALNNCVRARTR) with tryptone-capped NaGdF4 NDs (designated as Try-NaGdF4 NDs). MDA-MB-231 tumor could be easily tracked using in vivo MRI with PDL1-NaGdF4 ND enhancement because the as-prepared PDL1-NaGdF4 NDs have a high longitudinal relaxivity (r 1) value (22.8 mM-1 S-1) and accumulate in the tumor site through binding with programmed cell death ligand-1 (PD-L1)-overexpressed cells. A series of in vitro/in vivo results demonstrated that the PDL1-NaGdF4 NDs could effectively suppress MDA-MB-231 tumor growth in mice (66% volume ratio) by inhibiting migration and proliferation of tumor cells. In addition, the results of pharmacokinetic study showed that the PDL1-NaGdF4 NDs were excreted from the body through the kidneys. These results highlight the potential of PDL1-NaGdF4 NDs as a biocompatible nanomedicine for TNBC diagnosis and immunotherapy.

Immunomodulatory effects of tumor Lactate Dehydrogenase C (LDHC) in breast cancer

BACKGROUND

Immunotherapy has significantly improved outcomes for cancer patients; however, its clinical benefits vary among patients and its efficacy across breast cancer subtypes remains unclear. To enhance immunotherapy efficacy, it is important to gain more insight into tumor-intrinsic immunomodulatory factors that could serve as therapeutic targets. We previously identified Lactate Dehydrogenase C (LDHC) as a promising anti-cancer target due to its role in regulating cancer cell genomic integrity. In this study, we investigated the effects of tumor LDHC expression on immune responses.

METHODS

TIMER AND TIDE deconvolution methods were used to investigate the relationship between tumor LDHC expression, immune cell infiltration and T cell dysfunction. Multiplex cytokine assays and flow cytometry were used to assess the effect of LDHC knockdown on the secretion of inflammatory molecules and expression of immune checkpoint molecules in breast cancer cells and cancer cell-immune cell co-cultures. T cell activity was determined by IFN-γ ELISPot assays and 7-AAD flow cytometry.

RESULTS

TIMER and TIDE analyses revealed that tumor LDHC expression is associated with T cell dysfunction in breast cancer and poorer post-immunotherapy survival in melanoma. Silencing LDHC in breast cancer cell lines (MDA-MB-468, BT-549, HCC-1954) enhanced early T cell activation and cytolytic activity. To gain a better understanding of the underlying mechanisms, comparative analysis of the effects of LDHC knockdown in cancer cell monocultures and co-cultures was conducted. Following LDHC knockdown, we observed an increase in the secretion of tumor-derived pro-inflammatory cytokines (IFN-γ, GM-CSF, MCP-1, CXCL1), a decrease in the soluble levels of tumor-derived immunosuppressive factors (IL-6, Gal-9) and reduced tumor cell surface PD-L1 expression. In direct co-cultures, LDHC knockdown reduced the levels of pro-tumorigenic cytokines (IL-1β, IL-4 and IL-6) and increased the secretion of the chemokine CXCL1. In addition, the number of CD8 + T cells expressing PD-1 and CTLA-4 and the cell surface expression of CTLA-4, TIGIT, TIM3, and VISTA were reduced.

CONCLUSIONS

Our findings suggest that targeting LDHC could enhance anti-tumor immune responses by modulating cytokine and chemokine secretion in addition to impairing immune checkpoint signaling. Further studies are required to elucidate the molecular mechanisms by which LDHC modulates immune responses in breast cancer.

Revealing gut microbiota biomarkers associated with melanoma immunotherapy response and key bacteria-fungi interaction relationships: evidence from metagenomics, machine learning, and SHAP methodology

Introduction

The gut microbiota is associated with the response to immunotherapy in cutaneous melanoma (CM). However, gut fungal biomarkers and bacterial-fungal interactions have yet to be determined.

Methods

Metagenomic sequencing data of stool samples collected before immunotherapy from three independent groups of European ancestry CM patients were collected. After characterizing the relative abundances of bacteria and fungi, Linear Discriminant Analysis Effect Size (LEfSe) analysis, Random Forest (RF) model construction, and SHapley Additive exPlanations (SHAP) methodology were applied to identify biomarkers and key bacterial-fungal interactions associated with immunotherapy responders in CM.

Results

Diversity analysis revealed significant differences in the bacterial and fungal composition between CM immunotherapy responders and non-responders. LEfSe analysis identified 45 bacterial and 4 fungal taxa as potential biomarkers. After constructing the RF model, the AUC of models built using bacterial and fungal data separately were 0.64 and 0.65, respectively. However, when bacterial and fungal data were combined, the AUC of the merged model increased to 0.71. In the merged model, the following taxa were identified as important biomarkers: Romboutsia, Endomicrobium, Aggregatilinea, Candidatus Moduliflexus, Colwellia, Akkermansia, Mucispirillum, and Rutstroemia, which were associated with responders, whereas Zancudomyces was associated with non-responders. Moreover, the positive correlation interaction between Akkermansia and Rutstroemia is considered a key bacterial-fungal interaction associated with CM immunotherapy response.

Conclusion

Our results provide valuable insights for the enrichment of responders to immunotherapy in CM patients. Moreover, this study highlights the critical role of bacterial-fungal interactions in CM immunotherapy.

97 Machine learning algorithms in the prognosis of cutaneous melanoma: a population-based study

OBJECTIVES

To establish a predictive model for prognosis of cutaneous melanoma using machine learning algorithms in large sample data.

METHODS

A retrospective analysis of patients diagnosed with cutaneous melanoma in the SEER database from 2010 to 2015 was performed using 12 different machine learning algorithms, for a total of 97 algorithm combinations, to screen for variables associated with cutaneous melanoma prognosis and to build predictive models.

RESULTS

A total of 24,457 cases were collected in this study, and 8,441 cases were finally included. Among them, 5908 cases in the training set and 2533 cases in the test set. The results of the study show that StepCox[both] + RSF is the best model. The variable features screened by the best model were Sex, Age, Marital, T stage, N stage, Ulcer, Site, Histologic, Surgery, Chemotherapy, Bone metastasis, Liver metastasis and Lung metastasis.

CONCLUSION

We have developed a predictive model with good accuracy for cutaneous melanoma prognosis using a combination of 97 machine learning algorithms in a large sample database.

Identification of lactylation-associated fibroblast subclusters predicting prognosis and cancer immunotherapy response in colon cancer

BACKGROUND

Lactylation plays an important role in tumor progression. This study aimed to clarify the impact of lactylation on cancer-associated fibroblasts(CAFs).

METHODS

Single-cell and bulk RNA sequence data, along with survival information, were obtained from TCGA and GEO datasets. Significant lactylation-associated genes were acquired by differential analysis and used to construct a prognostic model via Cox and LASSO regression analyses. Next, single-cell analysis, enrichment and pathway analysis, pseudotemporal trajectory and survival analysis were used to identify significant lactylation-associated fibroblast subclusters in colon cancer. IMvigor210 and PRJEB23709 cohorts were applied to assess the response to immunotherapy. In vitro experiments were conducted to explore how lactylation affect fibroblasts.

RESULTS

We established a lactylation-associated prognostic model with 17 risk genes in TCGA and further validated it in GEO datasets. Single-cell analysis revealed the lactylation level of fibroblasts in colon cancer was greater than that in normal tissues. Moreover, five lactylation-associated fibroblast subclusters were identified via the NMF algorithm. Patients with lower scores of FB_2_CALD1, FB_3_TPM4 and FB_4_AHNAK subclusters had better clinical prognosis in colon cancer and were more likely to benefit from immunotherapy. Further experiments demonstrated that lactylation could enhance the proliferation, migration and invasion ability of fibroblasts and up-regulate the expression of COL1A1, which was similar to the effect of colon cancer cells.

CONCLUSION

This study identified key fibroblast subclusters with prognostic value and implied that lactylation might help transform fibroblasts into CAFs in colon cancer for the first time, which provides new paths for understanding the evolution of CAFs and cancer therapeutic strategies.

Single-cell transcriptomics of melanoma sentinel lymph nodes identifies immune cell signatures associated with metastasis

The sentinel lymph node (SLN) is the first lymph node encountered by a metastatic cancer cell and serves as a predictor of poor prognosis, as cases with clinically occult SLN metastases are classified as stage III with elevated rates of recurrence and diminished overall survival. However, the dynamics of immune infiltrates in SLNs remain poorly characterized. Here, using an unbiased cellular indexing of transcriptomes and epitopes by sequencing technique, we profiled 97,777 cells from SLN tissues obtained from patients with stages I/II and III cutaneous melanoma. We described the transcriptional programs of a multitude of T, B, and myeloid cell subtypes in SLNs. Based on the proportions of cell types, we determined that SLN subtypes stratified along a naive → activated axis; patients with a "high activated" signature score appeared to be undergoing a robust melanoma antigen-driven adaptive immune response and, thus, could be responsive to immunotherapy. Additionally, we identified transcriptomic signatures of SLN-infiltrating dendritic cell subsets that compromise antitumor immune responses. Our analyses provide valuable insights into tumor-driven immune changes in the SLN tissue, offering a powerful tool for the informed design of immune therapies for patients with high-risk melanoma.

PARP inhibitor radiosensitization enhances anti-PD-L1 immunotherapy through stabilizing chemokine mRNA in small cell lung cancer

Immunotherapy (IO) is an effective treatment for various cancers; however, the benefits are modest for small cell lung cancer (SCLC). The poor response of SCLC to anti-PD-1/PD-L1 IO is due in part to the lack of cytotoxic T cells because of limited chemokine expression from SCLC tumors. Immunogenic radiosensitizers that enhance chemokine expression may be a promising strategy forward. Here, we show that the PARP inhibitors (PARPi), including olaparib, talazoparib and veliparib, in combination with radiotherapy (RT) enhance the immune activation and anti-tumor efficacy in SCLC cell lines, patient-derived xenograft (PDX) and syngeneic mouse models. The effect is further enhanced by continued delivery of adjuvant PARPi. The combination treatment (PARPi with RT) activates the cGAS-STING pathway and increases the mRNA levels of the T cell chemo-attractants CCL5 and CXCL10. In addition to upregulation of transcription, the combination treatment increases chemokine CXCL10 protein levels via stabilization of CXCL10 mRNA in an EIF4E2-dependent manner. The incorporation of anti-PD-L1 IO into the PARPi with RT combination therapy further improves the anti-tumor efficacy by increasing T cell infiltration and function. This study thus provides a proof of principle for the combination of PARP inhibitors, RT and anti-PD-L1 IO as a treatment strategy for SCLC.

Harnessing phytochemicals: Innovative strategies to enhance cancer immunotherapy

Cancer immunotherapy has revolutionized cancer treatment, but therapeutic ineffectiveness-driven by the tumor microenvironment and immune evasion mechanisms-continues to limit its clinical efficacy. This challenge underscores the need to explore innovative approaches, such as multimodal immunotherapy. Phytochemicals, bioactive compounds derived from plants, have emerged as promising candidates for overcoming these barriers due to their immunomodulatory and antitumor properties. This review explores the synergistic potential of phytochemicals in enhancing immunotherapy by modulating immune responses, reprogramming the tumor microenvironment, and reducing immunosuppressive factors. Integrating phytochemicals with conventional immunotherapy strategies represents a novel approach to mitigating resistance and enhancing therapeutic outcomes. For instance, nab-paclitaxel has shown the potential in overcoming resistance to immune checkpoint inhibitors, while QS-21 synergistically enhances the efficacy of tumor vaccines. Furthermore, we highlight recent advancements in leveraging nanotechnology to engineer phytochemicals for improved bioavailability and targeted delivery. These innovations hold great promise for optimizing the clinical application of phytochemicals. However, further large-scale clinical studies are crucial to fully integrate these compounds into immunotherapeutic regimens effectively.

IL-27 elicits a cytotoxic CD8+ T cell program to enforce tumour control

Although cytotoxic CD8+ T lymphocytes (CTLs) are essential for anti-tumour immunity, they are frequently dysfunctional in tumours1. Cytokines that sustain CTL activity are attractive for cancer immunotherapy, but avoiding inflammatory toxicity remains a challenge for their clinical use2. Here we show that expression of a CTL signature is strongly associated with IL27 expression in human and mouse tumours. In mice, IL-27 acts directly on tumour-specific CTLs to promote their persistence and effector function in the tumour microenvironment. Moreover, treatment with inducible IL-27 overexpression or a half-life-extended IL-27 protein in vivo is well tolerated, induces regression of established tumours, drives an enhanced cytotoxic program in anti-tumour CTLs and synergizes with PD-L1 blockade. In patients with cancer who were treated with anti-PD-1/PD-L1 therapy, high expression of IL-27 correlates with a favourable clinical response, and IL-27 supports human CTL function during chronic antigen stimulation ex vivo. Our data demonstrate that endogenous IL-27 is essential for anti-tumour immunity and that IL-27 receptor agonism can safely improve anti-tumour T cell responses alone or in combination with PD-L1 blockade.

Platelets and megakaryocytes in cancer

Platelets have important roles in hemostasis but also actively participate in cancer metastasis and inflammatory processes. They are produced by large precursor cells, the megakaryocytes, residing mainly in the bone marrow. Clinically, elevated platelet counts and/or increased platelet-to-lymphocyte ratio are being explored as biomarkers of metastatic disease and to predict survival or response to therapy in certain cancers. Multiple mechanisms have been put forward on how platelets promote hematogenous metastasis stemming mainly from murine experimental models. Research is now beginning to explore the potential roles of megakaryocytes in solid cancer, myeloma, and lymphoma. Here, we review mechanisms on how platelets and megakaryocytes contribute to cancer progression and metastasis but also discuss potential cancer-suppressing functions mainly related to the regulation of vascular intratumor integrity. Recent developments in cancer immune checkpoint therapy are reviewed with a focus on the potential roles of platelets. Moreover, we review studies exploring platelets for targeted drug delivery systems in cancer therapy.

Spatial proteomics reveals sirtuin 1 to be a determinant of T-cell infiltration in human melanoma

BACKGROUND

The tumour microenvironment significantly influences the clinical response of patients to therapeutic immune checkpoint inhibition (ICI), but a comprehensive understanding of the underlying immune-regulatory proteome is still lacking.

OBJECTIVES

To decipher targetable biologic processes that determine tumour-infiltrating lymphocytes (TiLs) as a cellular equivalent of clinical response to ICI.

METHODS

We mapped the spatial distribution of proteins in TiL-enriched vs. TiL-low compartments in melanoma by combining microscopy, matrix-assisted laser desorption mass spectrometry imaging and liquid chromatography-mass spectrometry, as well as computational data mining. Pharmacological modulation of sirtuin 1 (SIRT1) activity in syngeneic mouse models was used to evaluate the efficacy of pharmacological SIRT1 activation in two syngeneic melanoma mouse models, one known to be α-programmed cell death protein 1 (PD-1) sensitive and the other α-PD-1 resistant.

RESULTS

Spatial proteomics and gene ontology-based enrichment analysis identified > 145 proteins enriched in CD8high tumour compartments, including negative regulators of mammalian target of rapamycin signalling such as SIRT1. Multiplexed immunohistochemistry confirmed that SIRT1 protein was expressed more in CD8high than in CD8low compartments. Further analysis of bulk and single-cell RNA sequencing data from melanoma tissue samples suggested the expression of SIRT1 by different lymphocyte subpopulations (CD8+ T cells, CD4+ T cells and B cells). Furthermore, we showed in vivo that pharmacological SIRT1 activation increased the immunological effect of α-PD-1 ICI against melanoma cells in mice, which was accompanied by an increase in T-cell infiltration and T-cell-related cytokines, including interferon (IFN)-γ, CCL4, CXCL9, CXCL10 and tumour necrosis factor-α. In silico analysis of large transcriptional data cohorts showed that SIRT1 was positively associated with the proinflammatory T-cell chemokines CXCL9, CXCL10 and IFN-γ, and prolonged overall survival of patients with melanoma.

CONCLUSIONS

Our study deciphers the proteomics landscape in human melanoma, providing important information on the tumour microenvironment and identifying SIRT1 as having important prognostic and therapeutic implications.

Induction of the p21/CDK6 pathway and alteration of the immune microenvironment by the stem cell marker CBX3 in melanoma

BACKGROUND

As one of the stem cell markers, chromobox protein homolog 3 (CBX3) participates in multiple signaling pathways that affect the progression of various tumors. However, the role of CBX3 in melanoma remains unclear, and the mechanisms by which CBX3 may regulate immunotherapy outcome remain largely unknown.

METHODS

We used the Cancer Genome Atlas, Genotype-Tissue Expression portal, and Gene Expression Omnibus database to estimate CBX3 expression and its prognostic effect in melanoma. The role of CBX3 in proliferation and migration of melanoma cells were examined using the CCK8, cloning, wound healing, and transwell assays. The effect of CBX3 on melanoma tumorigenesis was assessed using an in vivo animal model. The role of CBX3 in cell cycle was examined using flow cytometry, and expression levels of cell cycle-related genes and proteins in cells with altered CBX3 levels were analyzed using qPCR and western blotting. The function of CBX3 in the immune microenvironment of melanoma was studied using single-cell RNA sequencing and public databases.

RESULTS

We found that CBX3 was highly expressed in melanoma with poor prognosis. CBX3 promoted the proliferation and migration of melanoma cells in vivo and in vitro. Functional analysis revealed that CBX3 regulates cell cycle, as it accelerated the G1 to S transition, decreased p21 expression, and increased CDK6 expression. Finally, single-cell sequencing and immune-related assays showed that CBX3 is immunogenic and can change the immune microenvironment of melanoma.

CONCLUSIONS

We conclude that the stem cell marker, CBX3 activates the p21/CDK6 pathway and alters the immune microenvironment in melanoma.

VSIG4+ tumor-associated macrophages mediate neutrophil infiltration and impair antigen-specific immunity in aggressive cancers through epigenetic regulation of SPP1

V-set and immunoglobulin domain-containing 4 (VSIG4) positive tumor-associated macrophage (VSIG4+ TAM) is an immunosuppressive subpopulation newly identified in aggressive cancers. However, the mechanism how VSIG4+ TAMs mediate immune evasion in aggressive cancers have not been fully elucidated. In our study, we found targeting VSIG4+ TAMs by VSIG4 deficiency or blockade remarkably limited tumor growth and metastasis, especially those derived from anaplastic thyroid cancer (ATC) and pancreatic cancer, two extremely aggressive types. Moreover, the combination of VSIG4 blockade with a BRAF inhibitor synergistically enhanced anti-tumor activity in ATC-tumor bearing mice. VSIG4 deficiency recovered the antigen presentation (B2m, H2-k1, H2-d1) of TAMs and activated antigen-specific CD8+ T cells by promoting their in vivo proliferation and intratumoral infiltration. Notably, loss of VSIG4 in TAMs significantly reduced the production of lactate and histone H3 lysine 18 lactylation, resulting the decreased transcription of SPP1 mediated by STAT3, which collectively disrupted the cell-cell interactions between TAMs and neutrophils. Further combination of VSIG4 with SPP1 blockade synergistically boosted anti-tumor activity. Overall, our studies demonstrate the epigenetic regulation function of VSIG4 confers on TAMs an alternative pattern, beyond the checkpoint role of VSIG4, to shape the immunosuppressive tumor microenvironment and impair antigen-specific immunity against aggressive cancers.

Cancer Stem Cells and the Renin-Angiotensin System in the Tumor Microenvironment of Melanoma: Implications on Current Therapies

Multiple signaling pathways are dysregulated in melanoma, notably the Ras/RAF/MAPK/ERK and PI3K/AKT/mTOR pathways, which can be targeted therapeutically. The high immunogenicity of melanoma has been exploited using checkpoint inhibitors. Whilst targeted therapies and immune checkpoint inhibitors have improved the survival of patients with advanced melanoma, treatment resistance, their side effect profiles, and the prohibitive cost remain a challenge, and the survival outcomes remain suboptimal. Treatment resistance has been attributed to the presence of cancer stem cells (CSCs), a small subpopulation of pluripotent, highly tumorigenic cells proposed to drive cancer progression, recurrence, metastasis, and treatment resistance. CSCs reside within the tumor microenvironment (TME) regulated by the immune system, and the paracrine renin-angiotensin system, which is expressed in many cancer types, including melanoma. This narrative review discusses the role of CSCs and the paracrine renin-angiotensin system in the melanoma TME, and its implications on the current treatment of advanced melanoma with targeted therapy and immune checkpoint blockers. It also highlights the regulation of the Ras/RAF/MAPK/ERK and PI3K/AKT/mTOR pathways by the renin-angiotensin system via pro-renin receptors, and how this may relate to CSCs and treatment resistance, underscoring the potential for improving the efficacy of targeted therapy and immunotherapy by concurrently modulating the renin-angiotensin system.

Selective deficiency of mitochondrial respiratory complex I subunits Ndufs4/6 causes tumor immunogenicity

Cancer cells frequently rewire their metabolism to support proliferation and evade immune surveillance, but little is known about metabolic targets that could increase immune surveillance. Here we show a specific means of mitochondrial respiratory complex I (CI) inhibition that improves tumor immunogenicity and sensitivity to immune checkpoint blockade (ICB). Targeted genetic deletion of either Ndufs4 or Ndufs6, but not other CI subunits, induces an immune-dependent growth attenuation in melanoma and breast cancer models. We show that deletion of Ndufs4 induces expression of the major histocompatibility complex (MHC) class I co-activator Nlrc5 and antigen presentation machinery components, most notably H2-K1. This induction of MHC-related genes is driven by a pyruvate dehydrogenase-dependent accumulation of mitochondrial acetyl-CoA, which leads to an increase in histone H3K27 acetylation within the Nlrc5 and H2-K1 promoters. Taken together, this work shows that selective CI inhibition restricts tumor growth and that specific targeting of Ndufs4 or Ndufs6 increases T cell surveillance and ICB responsiveness.

Association of baseline neutrophil-to-lymphocyte ratio and prognosis in melanoma patients treated with PD-1/PD-L1 blockade: a systematic review and meta-analysis

Immunotherapy treatments that target programmed cell death receptor-1 (PD-1) or its ligand (PD-L1) have revolutionized the treatment of metastatic melanoma and currently represent the standard first-line treatment for this type of cancer. However, it is still not entirely clear which biomarkers are cost-effective, simple, and highly reliable. This systematic review and meta-analysis aims to analyze the predictive value of the baseline neutrophil-lymphocyte ratio (NLR) regarding disease progression and overall survival of patients with metastatic melanoma undergoing treatment with PD-1/PD-L1 blockade. PubMed, Scopus, and Web of Science were searched for studies comparing high versus low NLR. We performed the meta-analysis using RStudio v4.4.2 software. A total of 20 studies and 2691 patients were included, all with diagnoses of melanoma. The majority of the individuals were male 2278 (84, 65%). The median overall survival (OS) and progression-free survival (PFS) ranged from 5.0 to 44.4 and from 1.8 to 15.0 months, respectively. Compared with the high NLR ratio, the low exposure group achieved better rates of OS [hazard ratio (HR), 2.07; 95% CI, 1.73-2.48; P  < 0.00001; I ² = 47%]. Regarding PFS, there was a statistically significant difference between groups with tendencies toward the low NLR exposure group (HR, 1.59; 95% CI, 1.39-1.81; P  < 0.00001; I²=31%]. This systematic review and meta-analysis revealed significant lower OS in melanoma patients treated with PD-1/PD-L1 blockade who had elevated baseline NLR values. Furthermore, an increased PFS was observed in patients with a lower baseline NLR value. This study highlights NLR as an important prognostic biomarker for patients with metastatic melanoma who are candidates for treatment with PD-1 and PD-L1.

Lymphatic vessel network injury reduces local tumor control despite preservation of the tumor-draining lymph node

The lymphatic system plays complex, often contradictory, roles in many cancers, including melanoma; these roles include contributions to tumor cell metastasis and immunosuppression in the tumor microenvironment as well as generation of antitumor immunity. Advancing our understanding of lymphatic vessel involvement in regulating tumor growth and immune response may provide new therapeutic targets or treatment plans to enhance the efficacy of existing therapies. We utilized a syngeneic murine melanoma model in which we surgically disrupted the lymphatic vessel network draining from the tumor to the tumor-draining lymph node (TDLN) while leaving the TDLN intact. Although transport of lymphatic-specific molecular weight tracers to the TDLN remains present after surgery, disruption of the tumor-draining lymphatic vessels results in decreased local tumor control, as reflected in an increase in the rate of tumor growth and reduction in effector-like T cell infiltration into the tumor. Our findings suggest that preservation of the functional tumor-draining lymphatic network may be essential in promoting a robust antitumor immune response.

Combined PARP14 inhibition and PD-1 blockade promotes cytotoxic T cell quiescence and modulates macrophage polarization in relapsed melanoma

BACKGROUND

Programmed cell death 1 (PD-1) signaling blockade by immune checkpoint inhibitors (ICI) effectively restores immune surveillance to treat melanoma. However, chronic interferon-gamma (IFNγ)-induced immune homeostatic responses in melanoma cells contribute to immune evasion and acquired resistance to ICI. Poly ADP ribosyl polymerase 14 (PARP14), an IFNγ-responsive gene product, partially mediates IFNγ-driven resistance. PARP14 inhibition prolongs PD-1 blockade responses in preclinical models, but fails to achieve full tumor clearance, suggesting the involvement of additional resistance mechanisms.

METHODS

We identified a robust PARP14 catalytic inhibitor gene signature and evaluated its association with patient survival. Using preclinical models and single-cell RNA sequencing, we investigated immune and tumor cell adaptations to PARP14 inhibition combined with PD-1 blockade.

RESULTS

Combining PARP14 inhibition and PD-1 blockade suppressed tumor-associated macrophages while increasing proinflammatory memory macrophages. Moreover, this combination mitigated the terminal exhaustion of cytotoxic T cells by inducing a quiescent state, thereby preserving functionality. Despite the enhanced immune responses, tumor cells developed adaptive resistance by engaging alternative immune evasion pathways.

CONCLUSIONS

Although adaptive resistance mechanisms re-emerge, PARP14 inhibition combined with PD-1 blockade offers a promising strategy to enhance treatment outcomes and overcome ICI resistance in melanoma, as immune cells are primed for further therapeutic interventions that leverage the quiescent state.

Comprehensive single-cell pan-cancer atlas unveils IFI30+ macrophages as key modulators of intra-tumoral immune dynamics

Background

The convergence of macrophage-targeted strategies with immune checkpoint blockade therapies defines a pivotal avenue in contemporary tumor therapy. Identifying robust genetic regulators in this context is imperative.

Methods

This study elucidates IFI30's role in enhancing Major Histocompatibility Complex II (MHC-II) restriction antigen processing. Despite its recognition in cancer immunotherapy, IFI30 remains a nascent focus. Our approach involves a multi-omics analysis of IFI30 tumor immunological profile in the macrophage-mediated Tumor Microenvironment (TME), spanning various cancers and bolstered by rigorous co-culture laboratory work.

Results

IFI30 predominantly localizes in monocyte/macrophage populations, correlating strongly with immune cell infiltration. Substantiated by single-cell analysis, IFI30 exhibits significant functional enrichment in immune-related pathways. Co-expression with immune-related genes, including MHC elements and immune checkpoints, further validates its relevance.

Conclusion

Our study positions IFI30 as a promising immunotherapeutic target. Pan-cancer analyses and glioblastoma multiforme (GBM) investigations collectively underscore IFI30's potential as a TME modulator, particularly in its interaction with M2-macrophages. IFI30 emerges as a prospective intervention point in the immunotherapeutic landscape.

Signatures of H3K4me3 modification predict cancer immunotherapy response and identify a new immune checkpoint-SLAMF9

H3 lysine 4 trimethylation (H3K4me3) modification and related regulators extensively regulate various crucial transcriptional courses in health and disease. However, the regulatory relationship between H3K4me3 modification and anti-tumor immunity has not been fully elucidated. We identified 72 independent prognostic genes of lung adenocarcinoma (LUAD) whose transcriptional expression were closely correlated with known 27 H3K4me3 regulators. We constructed three H3K4me3 modification patterns utilizing the expression profiles of the 72 genes, and patients classified in each pattern exhibited unique tumor immune infiltration characteristics. Using the principal component analysis (PCA) of H3K4me3-related patterns, we constructed a H3K4me3 risk score (H3K4me3-RS) system. The deep learning analysis using 12,159 cancer samples from 26 cancer types and 725 cancer samples from 5 immunotherapy cohorts revealed that H3K4me3-RS was significantly correlated with cancer immune tolerance and sensitivity. Importantly, this risk-score system showed satisfactory predictive performance for the ICB therapy responses of patients suffering from several cancer types, and we identified that SLAMF9 was one of the immunosuppressive phenotype and immunotherapy resistance-determined genes of H3K4me3-RS. The mice melanoma model showed Slamf9 knockdown remarkably restrained cancer progression and enhanced the efficacy of anti-CTLA-4 and anti-PD-L1 therapies by elevating CD8 + T cell infiltration. This study provided a new H3K4me3-associated biomarker system to predict tumor immunotherapy response and suggested the preclinical rationale for investigating the roles of SLAMF9 in cancer immunity regulation and treatment.

Injectable supramolecular hydrogel co-loading abemaciclib/NLG919 for neoadjuvant immunotherapy of triple-negative breast cancer

The efficacy of cancer immunotherapy relies on a sufficient amount of functional immune cells. Triple-negative breast cancer lacks enough immune cell infiltration, and adjuvant therapy is necessary to prime anti-tumor immunity. However, the improvement in efficacy is unsatisfactory with concern about inducing systemic immunotoxicity. Herein, we create an abemaciclib-loaded supramolecular peptide hydrogel formed by peptide-drug amphiphiles for neoadjuvant immunotherapy of triple-negative breast cancer, where the amphiphile is a conjugate of a β-sheet-forming peptide with 1-cyclohexyl-2-(5H-imidazo[5,1-a]isoindol-5-yl)ethanol (NLG919), an inhibitor of indoleamine 2,3-dioxygenase 1. The hydrogel can be injected into the tumor site and retained for at least one week for the sustained release of both abemaciclib and NLG919. The abemaciclib is able to induce immunogenic cell death of cancer cells and increase interleukin-2 secretion by cytotoxic T lymphocytes. Abemaciclib adversely upregulates indoleamine 2,3-dioxygenase 1, whose kynurenine production activity is inhibited by NLG919. The neoadjuvant immunotherapy reduces tumor recurrence and pulmonary metastasis and prolongs the survival of animals. This hydrogel provides a potential platform for neoadjuvant immunotherapy of triple-negative breast cancer with reduced toxicity compared with free abemaciclib.

Blockade of TIPE2-Mediated Ferroptosis of Myeloid-Derived Suppressor Cells Achieves the Full Potential of Combinatory Ferroptosis and Anti-PD-L1 Cancer Immunotherapy

Although immune checkpoint blockade (ICB) therapy has attained unprecedented clinical success, the tolerance and immune suppression mechanisms evolved by tumor cells and their tumor microenvironment (TME) hinder its maximum anti-cancer potential. Ferroptosis therapy can partially improve the efficacy of ICB, but it is still subject to immune suppression by myeloid-derived suppressor cells (MDSCs) in the TME. Recent research suggests that an MDSC blockade can unleash the full therapeutic potential of the combined therapy of ferroptosis and ICB in liver cancer treatment. However, whether blocking the intrinsic ferroptosis pathways of MDSCs can relieve imidazole ketone erastin (IKE)-initiated ferroptosis-induced immune suppression and ultimately trigger the optimal therapeutic effect of the combined ferroptosis and ICB therapy is still unknown. Here, we report that TIPE2, a phospholipid transfer protein, regulated the ferroptosis susceptibility in MDSCs through reprogramming lipid peroxidation-related phosphatidylethanolamine (PE) and phosphatidylcholine (PC) species composition. TIPE2-deficient MDSCs resisted IKE-induced ferroptosis by up-regulating SLC7A11 and GPX4, and dissolved ferroptosis-induced immunosuppressive function by down-regulating lipid ROS whilst encouraging T cell proliferation and infiltration into tumor tissues to improve ferroptosis therapy. More importantly, TIPE2-deficient MDSCs achieved the full anti-tumor therapeutic potential of IKE-induced ferroptosis therapy and a PD-L1 blockade. These findings indicate that TIPE2 confers the ferroptosis sensitivity of MDSCs, and combining the targeting of the TIPE2 of MDSCs, ferroptosis therapy, and ICB is a novel therapeutic option for cancer treatment.

UBR5 in Tumor Biology: Exploring Mechanisms of Immune Regulation and Possible Therapeutic Implications in MPNST

Malignant peripheral nerve sheath tumor (MPNST) is a rare but aggressive soft-tissue sarcoma characterized by poor response to therapy. The primary treatment remains surgical resection with negative margins. Nonetheless, in the setting of neurofibromatosis type 1 (NF1), the five-year survival rate is at 20-50%, with recurrence occurring in up to 50% of individuals. For patients with metastatic and unresectable disease, current treatment options include cytotoxic chemotherapy, which offers minimal benefit, and most patients die within five years of diagnosis. Despite advances in targeted therapy focusing on inhibiting Ras signaling and its downstream effectors, clinical trials report minimal clinical benefit, highlighting the need to explore alternative pathways in MPNST pathogenesis. Here, we discuss the role of the E3 ubiquitin ligase, UBR5, in cancer progression and immune modulation across various malignancies, including breast, lung, and ovarian cancer. We focus on mechanisms by which UBR5 contributes to tumorigenesis, focusing on its influence on tumor microenvironment and immune modulation. Additionally, we explore UBR5's roles in normal tissue function, DNA damage response, metastasis, and therapeutic resistance, illustrating its multifaceted contribution to cancer biology. We discuss evidence implicating UBR5 in immune evasion and highlight its potential as a therapeutic target to enhance the efficacy of immune checkpoint blockade (ICB) therapy in MPNST, a tumor typically characterized by an immune cold microenvironment. We outline current immune-based strategies and challenges in MPNST management, ongoing efforts to shift the immune landscape in MPNST, and ultimately, we suggest that targeting UBR5 could be a novel strategy to potentiate ICB therapy-mediated anti-tumor immune response and clinical outcomes, particularly in MPNST patients with inoperable or metastatic disease.

Tumor microenvironment targeted nano-drug delivery systems for multidrug resistant tumor therapy

In recent years, nano-drug delivery systems (Nano-DDS) that target the tumor microenvironment (TME) to overcome multidrug resistance (MDR) have become a research hotspot in the field of cancer therapy. By precisely targeting the TME and regulating its unique pathological features, such as hypoxia, weakly acidic pH, and abnormally expressed proteins, etc., these Nano-DDS enable effective delivery of therapeutic agents and reversal of MDR. This scientific research community is increasing its investment in the development of diversified systems and exploring their anti-drug resistance potential. Therefore, it is particularly important to conduct a comprehensive review of the research progress of TME-targeted Nano-DDS in recent years. After a brief introduction of TME and tumor MDR, the design principle and structure of liposomes, polymer micelles and inorganic nanocarriers are focused on, and their characteristics as TME-targeted nanocarriers are described. It also demonstrates how these systems break through the cancer MDR treatment through various targeting mechanisms, discusses their synthetic innovation, research results and resistance overcoming mechanisms. The review was concluded with deliberations on the key challenges and future outlooks of targeting TME Nano-DDS in cancer therapy.

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.

Overcoming Resistance Mechanisms to Melanoma Immunotherapy

The advent of immune checkpoint inhibition has revolutionized treatment of advanced melanoma. While most patients derive survival benefit from established immunotherapies, notably monoclonal antibodies blocking cytotoxic T-lymphocyte antigen 4 and programmed cell death protein 1, a subset does not optimally respond due to the manifestation of innate or acquired resistance to these therapies. Combination regimens have proven efficacious relative to single-agent blockade, but also yield high-grade treatment toxicities that are often dose-limiting for patients. In this review, we discuss the significant strides made in the past half-decade toward expanding the melanoma immunotherapy treatment paradigm. These include newly approved therapies, adoption of neoadjuvant immunotherapy, and studies in the clinical trials pipeline targeting alternative immune checkpoints and key immunoregulatory molecules. We then review how developments in molecular and functional diagnostics have furthered our understanding of the tumor-intrinsic and -extrinsic mechanisms driving immunotherapy resistance, as well as highlight novel biomarkers for predicting treatment response. Throughout, we discuss potential approaches for targeting these resistance mechanisms in rational combination with established immunotherapies to improve outcomes for patients with melanoma.

Long-term outcomes among patients who respond within the first year to nivolumab plus ipilimumab or nivolumab monotherapy: A pooled analysis in 935 patients

PURPOSE

To investigate the predictive value of RECIST response within 3, 6, or 12 months on long-term survival, and explore differences between nivolumab+ipilimumab and nivolumab monotherapy, we analyzed pooled 5-year data of 935 responder and non-responder patients at various time points after treatment initiation in CheckMate 069, 066, and 067 studies.

PATIENTS AND METHODS

Treatment-naive advanced melanoma patients received nivolumab+ipilimumab or nivolumab monotherapy. To decrease immortal time bias, 3-, 6-, or 12-month overall survival (OS) and progression-free survival (PFS) landmark analyses were performed. Association between characteristics and response was evaluated by univariate and multivariate analyses.

RESULTS

Response rates at any time were 58 % (239/409) for nivolumab+ipilimumab and 44 % (230/526) for nivolumab monotherapy. In 12-month landmark analyses, 5-year OS rates for responders versus non-responders were 82 % versus 40 % with nivolumab+ipilimumab (HR=0.23 [95 % CI, 0.15-0.35]) and 76 % versus 32 % with nivolumab monotherapy (HR=0.22 [95 % CI, 0.16-0.31]). PFS rates were 83 % versus 32 % and 69 % versus 46 %, respectively. Similar strong associations between response at 3 and 6 months and 5-year OS and PFS were also observed with more than 70 % of the responses observed in the first 3 months. Response rates correlated with baseline LDH and PD-L1 status by multivariate analysis but the association between response and long-term survival was maintained in landmark analyses even among patients with high LDH and low PD-L1 expression.

CONCLUSION

Clinical response evaluated in the first months of therapy is a strong predictor of long-term survival, even in patients with poor prognostic biomarkers.