Quiescent cancer cells resist T cell attack by forming an immunosuppressive niche

Transforming the Tumor Microenvironment: An Outstanding AIE-Active Photosensitizer to Boost the Effectiveness of Immunotherapy

Immunotherapy, currently the most promising therapeutic approach for cancer, has shown significant efficacy. However, its clinical effectiveness is often constrained by such factors as tumor heterogeneity, the abundance of M2 macrophages, tumor-vascular hypoxia, and the immunosuppressive microenvironment created by immune checkpoint (IC) complexes. In this work, an effective photosensitizer (TSPA) with aggregation-induced emission (AIE) nature is adopted to counter above limitations. The synthesized TSPA demonstrated potent efficacy in eradicating primary tumors because of their effective generation reactive oxygen species (ROS) after undergoing photodynamic therapy (PDT) process. Moreover, TSPA can improve hypoxic conditions in tumor by normalizing blood vessels, and can instigate immunogenic cell death (ICD), thus stimulating immune cell activation. TSPA demonstrates the ability to reprogram M2 tumor-associated macrophages (TAMs) into the anti-tumor M1 phenotype, thereby increasing the infiltration of M1 macrophages within the tumor. This procedure notably ameliorates the immune microenvironment, effectively suppressing the long-term metastasis of breast cancer (BC). This research notably enhances the efficiency of tumor immunotherapy and is anticipated to emerge as a new strategy for improving the tumor's immunosuppressive microenvironment and overcoming immune evasion.

Integrated bioinformatic analysis identifies GADD45B as an immune-related prognostic biomarker in skin cutaneous melanoma

Skin cutaneous melanoma (SKCM) arises from melanocytes and is an aggressive form of skin cancer. If left untreated, most melanomas will metastasize, posing a major health risk. GADD45B, a member of the GADD45 family, is known to be involved in DNA damage repair; however, its specific role in SKCM remains largely unclear. In this study, we comprehensively investigated the function of GADD45B in SKCM. By integrating 26 SKCM-related datasets from The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE), cBioPortal for Cancer Genomics (cBioPortal), Gene Expression Omnibus (GEO), and other databases, we conducted functional enrichment, immune infiltration, and single-cell analyses using R. Additionally, transcriptome sequencing of 30 human SKCM cell lines, phenotype characterization of 29 SKCM lines in vitro, and macrophage polarization analysis were performed. We found that GADD45B expression was significantly downregulated in SKCM patients compared to normal controls (p < 0.001), and higher GADD45B levels correlated with better prognosis (p < 0.05). GADD45B also showed high diagnostic accuracy, with an area under the curve (AUC) of 0.986. GO and KEGG analyses revealed a strong association between GADD45B and immune-related pathways. Gene Set Variation Analysis (GSVA) and single-cell sequencing suggested that GADD45B may serve as a novel immune checkpoint, predominantly expressed in macrophages and promoting M1 polarization. In vitro, overexpression of GADD45B significantly inhibited SKCM cell proliferation, potentially via suppression of the PI3K/Akt signaling pathway, and also reduced chemotherapy resistance. Furthermore, in vivo experiments using a xenograft mouse model demonstrated that GADD45B overexpression significantly suppressed tumor growth. Mice injected with GADD45B-overexpressing tumor cells exhibited smaller tumor volumes from day 15 onwards compared to controls, with markedly reduced tumor volume and weight at the endpoint. These results underscore the potential of GADD45B as an effective tumor suppressor in SKCM. In conclusion, our findings highlight GADD45B as a key regulator in SKCM progression, capable of restraining tumor cell proliferation and enhancing apoptosis. GADD45B holds promise as a novel diagnostic and prognostic biomarker and a potential target for SKCM immunotherapy.

Tumor immune microenvironment remodeling after neoadjuvant therapy in gastric cancer: Update and new challenges

Gastric cancer (GC) is a malignant tumor with one of the highest morbidity and death rates in the world. Neoadjuvant therapy, including neoadjuvant chemotherapy (NAC) and NAC combined with immunotherapy, can improve the resection and long-term survival rates. However, not all patients respond well to neoadjuvant therapy. It has been confirmed that immune cells in the tumor immune microenvironment, including T cells, B cells, and natural killer cells, can affect the efficacy of neoadjuvant therapy. This paper summarizes current preclinical and clinical evidence to more fully describe the effects of neoadjuvant therapy on the immune microenvironment of GC, to provide the impetus to identify biomarkers to predict the potency of neoadjuvant therapy, and to identify the mechanisms of drug resistance, which should promote the development of individualized and accurate treatments for GC patients.

Mitochondrial reactive oxygen species promote cancer metastasis and tumor microenvironment immunosuppression through gasdermin D

Although recent research has established that gasdermin D (GSDMD), a factor that drives pyroptosis, is essential for cell death and inflammation, its involvement in cancer metastasis has yet to be elucidated. In this study, GSDMD was significantly increased in lung neutrophils at the metastatic stage from a murine orthotropic 4T1 breast cancer model. Moreover, the N terminal domain from cleaved GSDMD exhibited a positive correlation with increased mitochondrial reactive oxygen species (mROS) and serum high mobility group box 1 (HMGB-1) levels. Mechanistically, mROS inhibition significantly suppressed GSDMD-N oligomerization and pore formation. In addition, the activation of GSDMD significantly enhanced the formation of neutrophil extracellular traps (NETs) following treatment with Cathepsin C. Within a murine orthotopic breast cancer model using 4T1 cell line, the inhibition of GSDMD through the application of LDC7559 significantly attenuated the metastatic spread of breast cancer to the lung. In addition, knockout of GSDMD reduced lung metastasis in E0771 intravenous injection murine model. Furthermore, inhibition of GSDMD reduced the number of myeloid derived suppressor cells (MDSC) in the metastatic lung of breast cancer mouse model, while concurrently increasing both the percentage and total cell count of CD8+ T cells, suggesting that mitochondrial dysfunction-dependent GSDMD activation promotes tumor microenvironment immunosuppression and NETs. GSDMD represents a promising therapeutic target for mitigating the metastatic progression of breast cancer to the lung.

Global analysis of protein turnover dynamics in single cells

Single-cell proteomics (SCPs) has advanced significantly, yet it remains largely unidimensional, focusing primarily on protein abundances. In this study, we employed a pulsed stable isotope labeling by amino acids in cell culture (pSILAC) approach to simultaneously analyze protein abundance and turnover in single cells (SC-pSILAC). Using a state-of-the-art SCP workflow, we demonstrated that two SILAC labels are detectable from ∼4,000 proteins in single HeLa cells recapitulating known biology. We performed a large-scale time-series SC-pSILAC analysis of undirected differentiation of human induced pluripotent stem cells (iPSCs) encompassing 6 sampling times over 2 months and analyzed >1,000 cells. Protein turnover dynamics highlighted differentiation-specific co-regulation of protein complexes with core histone turnover, discriminating dividing and non-dividing cells. Lastly, correlating cell diameter with the abundance of individual proteins showed that histones and some cell-cycle proteins do not scale with cell size. The SC-pSILAC method provides a multidimensional view of protein dynamics in single-cell biology.

Hypoxia-inducible factor-targeting therapy augmented the sensitivity to programmed death ligand-1 blockade by enhancing interferon-γ-induced chemokines in tumor cells

Immune checkpoint inhibitors (ICIs) targeting programmed death ligand-1 (PD-L1) provide clinical benefits for various advanced malignancies. However, the predictive factors that determine sensitivity to ICIs have not been fully elucidated. We focused on tumor-derived CXCL10/11 as a pivotal factor that determines the response to PD-L1 blockade by regulating T cell accumulation and tumor angiogenesis. We previously reported that CXCL10/11 was upregulated by interferon (IFN)-γ in ICI-sensitive tumor cells but not in ICI-resistant cells, including mouse Lewis lung carcinoma (LLC). In the present study, gene silencing of tumor-derived CXCL10/11 induced resistance to PD-L1 blockade in AB1-HA mesothelioma cell-bearing mice. To identify the mechanisms underlying ICI resistance, we performed a microarray analysis to compare the IFN-γ-inducible genes between ICI-sensitive AB1-HA and ICI-resistant LLC in vitro. A pathway analysis based on microarray data indicated that hypoxia-inducible factor (HIF) 1A is the key signal that inhibits CXCL10/11 expression. We revealed that the HIF1A inhibitors echinomycin (EC) and YC-1 upregulated CXCL10/11 genes induced by IFN-γ in tumor cells in vitro. In addition, combination therapy with PD-L1 blockade and EC demonstrated synergistic antitumor effects in LLC-bearing mice. Combination therapy enhanced tumor infiltration of CD8 T cells and suppressed tumor angiogenesis. The present study suggests that HIF1A signaling in tumor cells dominates ICI resistance via the downregulation of tumor-derived CXCL10/11.

Perturbing local steroidogenesis to improve breast cancer immunity

Breast cancer, particularly triple-negative breast cancer (TNBC), evades the body's immune defences, in part by cultivating an immunosuppressive tumour microenvironment. Here, we show that suppressing local steroidogenesis can augment anti-tumour immunity against TNBC. Through targeted metabolomics of steroids coupled with immunohistochemistry, we profiled the existence of immunosuppressive steroids in TNBC patient tumours and discerned the steroidogenic activity in immune-infiltrating regions. In mouse, genetic inhibition of immune cell steroidogenesis restricted TNBC tumour progression with a significant reduction in immunosuppressive components such as tumour associated macrophages. Steroidogenesis inhibition appears to bolster anti-tumour immune responses in dendritic and T cells by impeding glucocorticoid signalling. Undertaking metabolic modelling of the single-cell transcriptomics and targeted tumour-steroidomics, we pinpointed the predominant steroidogenic cells. Inhibiting steroidogenesis pharmacologically using a identified drug, posaconazole, curtailed tumour expansion in a humanised TNBC mouse model. This investigation paves the way for targeting steroidogenesis and its signalling pathways in breast cancer affected by immune-steroid maladaptation.

Drug Delivery Platform Targeting MMP9 in Combination with Photothermal Therapy to Improve Tumor Chemosensitivity

Tumor chemotherapy insensitivity poses a significant challenge in cancer treatment, with angiogenesis being a key contributing factor. Angiogenesis supplies oxygen and nutrients to tumor cells, thereby impairing treatment outcomes. Based on these findings, an MMP9-responsive carbon quantum dot-based nanoplatform (MMP9i@MTX@CQDs) encapsulating methotrexate (MTX) and an MMP9 inhibitor (MMP9i) is developed to overcome chemotherapy insensitivity. Targeting the high expression of MMP9 in tumors, the platform releases its payload in a responsive manner. Under near-infrared (NIR) irradiation, the system effectively downregulated angiogenesis-related molecules, including VEGF and CD31, and inhibited the Wnt/β-catenin signaling pathway, thereby reversing chemotherapy insensitivity. This nanoplatform integrates MMP9-responsive CQDs with MTX, enabling photothermal therapy (PTT) and MMP9 inhibition, offering a robust and safe strategy to sensitize tumors to chemotherapy.

Breast cancer patient-derived scaffolds enhance the understanding of PD-L1 regulation and T cell cytotoxicity

Recent advances as well as obstacles for immune-based cancer treatment strategies, highlight the notable impact of patient cancer microenvironments on the immune cells and immune targets. Here, we use patient-derived scaffolds (PDS) generated from 110 primary breast cancers to monitor the impact of the cancer microenvironment on immune regulators. Pronounced variation in PD-L1 expression is observed in cancer cells adapted to different patient scaffolds. This variation is further linked to clinical observations and correlated with specific proteins detected in the cell-free PDSs using mass spectrometry. When adding T cells to the PDS-based cancer cultures, the killing efficiency of activated T cells vary between the cultures, whereas non-activated T cells modulate the cancer cell PD-L1 expression to treatment-predictive values, matching killing capacities of activated T cells. Surviving cancer cells show enrichment in cancer stem cell and epithelial-to-mesenchymal transition (EMT) features, suggesting that T cells may not efficiently target cells with metastatic potential. We conclude that clinically relevant insights in how to optimally target and guide immune-based cancer therapies can be obtained by including patient-derived scaffolds and cues from the cancer microenvironment in cancer patient handling and drug development.

CAF-derived exosomal LINC01711 promotes breast cancer progression by activating the miR-4510/NELFE axis and enhancing glycolysis

Breast cancer (BRCA) is among the most prevalent malignancies in women, characterized by a complex tumor microenvironment significantly influenced by cancer-associated fibroblasts (CAFs). CAFs contribute to tumor progression by secreting exosomes that can modulate cancer cell behavior. This study highlights how CAF-derived exosomes transmit the long non-coding RNA (lncRNA) LINC01711, which activates TXN through the miR-4510/NELFE axis, thereby enhancing glycolysis in BRCA cells. Utilizing BRCA single-cell sequencing data from the GEO database, the study employed dimensionality reduction, clustering, and cell annotation techniques to uncover the central role of NELFE in BRCA. Experimental findings revealed that LINC01711 is highly expressed in CAF-derived exosomes, which upregulate TXN via the miR-4510/NELFE axis, promoting the glycolytic pathway and subsequently increasing the proliferation, migration, and invasion potential of BRCA cells. These results shed light on a novel molecular mechanism underlying BRCA progression and suggest potential targets for therapeutic intervention.

Targeting DKK3 to remodel tumor immune microenvironment and enhance cancer immunotherapy

Cancer immunotherapy such as immune checkpoint blockade (ICB) therapy has made important breakthroughs in cancer treatment, however, currently only parts of cancer patients benefit from ICB therapy. The suppressive tumor immune microenvironment (TIME) impedes the treatment response of immunotherapy, indicating the necessity to explore new treatment targets. Here, we reported a new potential immunotherapeutic target, Dickkopf-3 (DKK3), for cancer treatment. DKK3 expression is up-regulated in the tumors from multiple cancer types, and high DKK3 expression is associated with worse survival outcome across different cancers. We observed that DKK3 directly inhibits the activation of CD8+ T cells and the Th1 differentiation of CD4+ T cells ex vivo. Also, by establishing four different mouse cancer models, we found that DKK3 blockade triggers effective anti-tumor effects and improve the survival of tumor-bearing mice in vivo. DKK3 blockade also remodels the suppressive TIME of different cancer types, including the increased infiltration of CD8+ T cells, IFN-γ+CD8+ T cells, Th1 cells, and decreased infiltration of M2 macrophages and MDSCs in the TIME. Moreover, we found that combined blockade of DKK3 and PD-1 induces synergistic tumor-control effect in our mouse cancer model. Therefore, our study reveals the impact of DKK3 in the TIME and cancer progression, which suggests that DKK3 is a novel and promising immunotherapeutic target for enhanced cancer immunotherapy.

Cancer-associated fibroblasts in breast cancer in the single-cell era: Opportunities and challenges

Breast cancer is a leading cause of morbidity and mortality in women, and its progression is closely linked to the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs), key components of the TME, play a crucial role in promoting tumor growth by driving cancer cell proliferation, invasion, extracellular matrix (ECM) remodeling, inflammation, chemoresistance, and immunosuppression. CAFs exhibit considerable heterogeneity and are classified into subgroups based on different combinations of biomarkers. Single-cell RNA sequencing (scRNA-seq) enables high-throughput and high-resolution analysis of individual cells. Relying on this technology, it is possible to cluster complex CAFs according to different biomarkers to analyze the specific phenotypes and functions of different subpopulations. This review explores CAF clusters in breast cancer and their associated biomarkers, highlighting their roles in disease progression and potential for targeted therapies.

Targeting the tumour cell surface in advanced prostate cancer

Prostate cancer remains a substantial health challenge, with >375,000 annual deaths amongst men worldwide. Most prostate cancer-related deaths are attributable to the development of resistance to standard-of-care treatments. Characterization of the diverse and complex surfaceome of treatment-resistant prostate cancer, combined with advances in drug development that leverage cell-surface proteins to enhance drug delivery or activate the immune system, have provided novel therapeutic opportunities to target advanced prostate cancer. The prostate cancer surfaceome, including proteins such as prostate-specific membrane antigen (PSMA), B7-H3, six transmembrane epithelial antigen of the prostate 1 (STEAP1), delta-like ligand 3 (DLL3), trophoblastic cell-surface antigen 2 (TROP2), prostate stem cell antigen (PSCA), HER3, CD46 and CD36, can be exploited as therapeutic targets, as regulatory mechanisms might contribute to the heterogeneity of expression of these proteins and subsequently affect treatment response and resistance. Specific treatment strategies targeting the surfaceome are in clinical development, including radionuclides, antibody-drug conjugates, T cell engagers and chimeric antigen receptor (CAR) T cells. Ultimately, biomarker development and clinical implementation of these agents will be informed and refined by further understanding of the biology of various targets; the target specificity and sensitivity of different agents; and off-target and toxic effects associated with these agents. Understanding the dynamic nature of cell-surface targets and non-overlapping expression patterns might also lead to future combinational strategies.

Targeted editing of CCL5 with CRISPR-Cas9 nanoparticles enhances breast cancer immunotherapy

Breast cancer remains one of the leading causes of cancer-related mortality among women worldwide. Immunotherapy, a promising therapeutic approach, often faces challenges due to the immunosuppressive tumor microenvironment. This study explores the innovative use of CRISPR-Cas9 technology in conjunction with FCPCV nanoparticles to target and edit the C-C Motif Chemokine Ligand 5 (CCL5) gene, aiming to improve the efficacy of breast cancer immunotherapy. Single-cell RNA sequencing (scRNA-seq) and TCGA-BRCA data identified CCL5 as a key immune-related gene in breast cancer. Using CRISPR-Cas9, sgRNA targeting CCL5 was designed and delivered to breast cancer cells and humanized mouse models via FCPCV nanoparticles. In vitro experiments demonstrated that FCPCV nanoparticles effectively silenced CCL5, enhanced CD8+ T cell activity, and increased the production of cytokines such as IFN-γ, TNF-α, and GZMB. In vivo studies revealed significant tumor suppression, improved immune microenvironment, and increased CD8+/CD4+ ratios in treated mice, without notable toxic side effects. These findings highlight the potential of CRISPR-Cas9 nanoparticle-mediated gene editing as a novel strategy for enhancing breast cancer immunotherapy, providing a new direction for personalized and effective cancer treatment.

Dendritic cell maturation in cancer

Dendritic cells (DCs) are specialized antigen-presenting cells that are present at low abundance in the circulation and tissues; they serve as crucial immune sentinels by continually sampling their environment, migrating to secondary lymphoid organs and shaping adaptive immune responses through antigen presentation. Owing to their ability to orchestrate tolerogenic or immunogenic responses to a specific antigen, DCs have a pivotal role in antitumour immunity and the response to immune checkpoint blockade and other immunotherapeutic approaches. The multifaceted functions of DCs are acquired through a complex, multistage process called maturation. Although the role of inflammatory triggers in driving DC maturation was established decades ago, less is known about DC maturation in non-inflammatory contexts, such as during homeostasis and in cancer. The advent of single-cell technologies has enabled an unbiased, high-dimensional characterization of various DC states, including mature DCs. This approach has clarified the molecular programmes associated with DC maturation and also revealed how cancers exploit these pathways to subvert immune surveillance. In this Review, we discuss the mechanisms by which cancer disrupts DC maturation and highlight emerging therapeutic opportunities to modulate DC states. These insights could inform the development of DC-centric immunotherapies, expanding the arsenal of strategies to enhance antitumour immunity.

Antigenic cancer persister cells survive direct T cell attack

Drug-tolerant persister cancer cells were first reported fifteen years ago as a quiescent, reversible cell state which tolerates unattenuated cytotoxic drug stress. It remains unknown whether a similar phenomenon contributes to immune evasion. Here we report a persister state which survives weeks of direct cytotoxic T lymphocyte (CTL) attack. In contrast to previously known immune evasion mechanisms that avoid immune attack, antigenic persister cells robustly activate CTLs which deliver Granzyme B, secrete IFNγ, and induce tryptophan starvation resulting in apoptosis initiation. Instead of dying, persister cells paradoxically leverage apoptotic caspase activity to avoid inflammatory death. Furthermore, persister cells acquire mutations and epigenetic changes which enable outgrowth of CTL-resistant cells. Persister cell features are enriched in inflamed tumors which regressed during immunotherapy in vivo and in surgically resected human melanoma tissue under immune stress ex vivo. These findings reveal a persister cell state which is a barrier to immune-mediated tumor clearance.

DHDH-mediated D-xylose metabolism induces immune evasion in triple-negative breast cancer

BACKGROUND

Although the prognosis of triple-negative breast cancer (TNBC) has significantly improved in the era of immunotherapy, many TNBC patients are resistant to therapies, and their disease progresses rapidly. Deciphering the metabolic mechanisms regulating anticancer immunity will provide new insights into therapeutic strategies for TNBC.

METHODS

In this study, we performed bioinformatics analysis in our multi-omics TNBC database and identified that a metabolic enzyme, dihydrodiol dehydrogenase (DHDH), might promote the phenotype of "cold tumor" in TNBC. The biological function of DHDH was verified by in vitro and in vivo functional experiments, and the potential molecular mechanism of DHDH promoting TNBC immune escape was further explored.

FINDINGS

Mechanistically, DHDH mediated the synthesis and depletion of the substrate D-xylose and inhibited the activation of the proteasome subunit beta type 9 (PSMB9) and further induction of the immune response. We demonstrated that D-xylose supplementation could enhance the proliferation of CD8+ T cells and the expression of cytotoxic markers against cocultured DHDH-wild type (WT) cells. Consistently, D-xylose supplementation in vivo promoted CD8+ T cell infiltration and the expression of cytotoxic markers and increased the sensitivity of DHDH-overexpressing tumors to immune checkpoint blockade (ICB).

CONCLUSIONS

Our findings reveal that a D-xylose-regulated PSMB9-dependent pathway governs tumor-intrinsic immunogenicity and, hence, the sensitivity to ICB, which may provide approaches to promote the "cold-to-hot" transition in TNBC.

FUNDING

This study was funded by the National Key Research and Development Plan of China, Shanghai Science and Technology Commission, National Natural Science Foundation of China, and China Postdoctoral Science Foundation.

Quantifying and interpreting biologically meaningful spatial signatures within tumor microenvironments

The tumor microenvironment (TME) plays a crucial role in orchestrating tumor cell behavior and cancer progression. Recent advances in spatial profiling technologies have uncovered novel spatial signatures, including univariate distribution patterns, bivariate spatial relationships, and higher-order structures. These signatures have the potential to revolutionize tumor mechanism and treatment. In this review, we summarize the current state of spatial signature research, highlighting computational methods to uncover spatially relevant biological significance. We discuss the impact of these advances on fundamental cancer biology and translational research, address current challenges and future research directions.

Integrated analysis of single-cell and bulk RNA sequencing identifies APOC1 as a biomarker and therapeutic target for G0/G1 cell cycle arrest in cholangiocarcinoma

Cholangiocarcinoma is characterized by its high malignancy, frequent recurrence and insensitivity to conventional radiotherapy and chemotherapy. This resistance may be associated with the presence of cells in the G0/G1 arrest phase within the cancer. Cancer cells in the G0/G1 phase are resistant to therapies targeting actively dividing cells, allowing them to evade conventional adjuvant treatments and survive. When conditions become favorable, these quiescent cells can re-enter the cell cycle, proliferate and potentially contribute to cancer recurrence. However, the biomarkers for identifying cells in the G0/G1 arrest phase within cholangiocarcinoma and the molecular mechanisms inducing G0/G1 arrest remain unclear. In our study, we first identified APOC1 as a characteristic gene for G0/G1 phase arrest in cholangiocarcinoma through bulk RNA sequencing (bulkRNA-seq). We then used single-cell RNA sequencing(scRNA-seq) for cell cycle inference and localized the expression peaks of APOC1 to verify its active cell cycle phase. Our experiments demonstrated that APOC1 can induce G0/G1 phase arrest in cholangiocarcinoma cells by inhibiting the Wnt/β-catenin signaling pathway, thereby suppressing cell proliferation, migration and invasion. This suggests that APOC1 may serve as a key regulatory factor and an important biomarker for cells in the G0/G1 phase of cholangiocarcinoma.

Targeting TRAP1-dependent metabolic reprogramming to overcome doxorubicin resistance in quiescent breast cancer

AIMS

TRAP1 is involved in metabolic reprogramming and promotes drug resistance. We aimed to explore whether a novel HSP90 inhibitor, C210, overcomes doxorubicin (DOX) resistance of quiescent breast cancer cells by targeting TRAP1.

METHODS

Breast cancer cells were induced to quiescence by hypoxia and low glucose. The relationship of cell metabolism with HSP90 and TRAP1 was investigated by Western blotting, ECAR, OCR, mitochondrial complex activity, and proteomic analysis. The targets of C210 and their functions were analyzed by SPR and immunoprecipitation. The antitumor effect in vivo was investigated with mouse tumor model.

RESULTS

In hypoxia and glucose deprivation, breast cancer cells exhibited elevated TRAP1 and an OXPHOS-enhanced quiescent phenotype. These cells were highly resistant to DOX but more sensitive to C210. C210 disrupted TRAP1's interaction with OXPHOS-associated client proteins, prompting proteasome-dependent degradation of these proteins, thereby reducing OCR, mitochondrial ATP production and resulting in selective elimination of the quiescent cancer cells by inducing mitochondrial apoptosis which could be reversed by exogenous ATP. Moreover, C210 targeted glycolytic, amino acid, and β-oxidation-associated proteome. C210 demonstrated promising in vivo anticancer efficacy which was particularly related to OXPHOS inhibition.

CONCLUSIONS

C210 eliminates DOX-resistant quiescent breast cancer cells by targeting TRAP1-dependent bioenergetics.

Tumour hypoxia in driving genomic instability and tumour evolution

Intratumour hypoxia is a feature of all heterogenous solid tumours. Increased levels or subregions of tumour hypoxia are associated with an adverse clinical prognosis, particularly when this co-occurs with genomic instability. Experimental evidence points to the acquisition of DNA and chromosomal alterations in proliferating hypoxic cells secondary to inhibition of DNA repair pathways such as homologous recombination, base excision repair and mismatch repair. Cell adaptation and selection in repair-deficient cells give rise to a model whereby novel single-nucleotide mutations, structural variants and copy number alterations coexist with altered mitotic control to drive chromosomal instability and aneuploidy. Whole-genome sequencing studies support the concept that hypoxia is a critical microenvironmental cofactor alongside the driver mutations in MYC, BCL2, TP53 and PTEN in determining clonal and subclonal evolution in multiple tumour types. We propose that the hypoxic tumour microenvironment selects for unstable tumour clones which survive, propagate and metastasize under reduced immune surveillance. These aggressive features of hypoxic tumour cells underpin resistance to local and systemic therapies and unfavourable outcomes for patients with cancer. Possible ways to counter the effects of hypoxia to block tumour evolution and improve treatment outcomes are described.

Collagen remodeling-mediated signaling pathways and their impact on tumor therapy

In addition to their traditional roles in maintaining tissue morphology and organ development, emerging evidence suggests that collagen (COL) remodeling-referring to dynamic changes in the quantity, stiffness, arrangements, cleavage states, and homo-/hetero-trimerization of COLs-serves as a key signaling mechanism that governs tumor growth and metastasis. COL receptors act as switches, linking various forms of COL remodeling to different cell types during cancer progression, including cancer cells, immune cells, and cancer-associated fibroblasts. In this review, we summarize recent findings on the signaling pathways mediated by COL arrangement, cleavage, and trimerization states (both homo- and hetero-), as well as the roles of the primary COL receptors-integrin, DDR1/2, LAIR-1/2, MRC2, and GPVI-in cancer progression. We also discuss the latest therapeutic strategies targeting COL fragments, cancer-associated fibroblasts, and COL receptors, including integrins, DDR1/2, and LAIR1/2. Understanding the pathways modulated by COL remodeling and COL receptors in various pathological contexts will pave the way for developing new precision therapies.

Integrated bioinformatics investigation and experimental validation reveals the clinical and biological significance of chromobox family in breast cancer

Chromobox (CBX) proteins are essential components of the Polycomb group and play pivotal roles in tumor onset, progression, and metastasis. However, the prognostic significance and functions of CBXs in the advancement of breast cancer (BC) have not been sufficiently investigated. A comprehensive analysis of the expression and prognostic relevance of CBX1-8 in BC was conducted comprehensively using The Cancer Genome Atlas (TCGA) and multiple databases. High mRNA expression of CBX2, CBX3, and CBX5 in BC patients was significantly associated with reduced overall survival (OS). Results from univariate and multivariate Cox regression analysis revealed that the mRNA expression level of CBX2 in BC patients served as an independent prognostic factor. In Luminal A and Luminal B BC subtypes, high expression of CBX2 correlated with unfavorable prognosis. Subsequent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated a strong association between CBX2 and the cell cycle as well as DNA replication processes. CCK-8 and EdU assays demonstrated that silencing CBX2 inhibited the proliferation of T47D and MCF7 cell lines. Moreover, the cell cycle assay indicated that CBX2 silencing led to cell cycle arrest, accompanied by a significant decrease in the levels of CDK4 and CyclinD1. Elevated CBX2 expression significantly correlated with the infiltration of T cells, B cells, macrophages, and dendritic cells in BC. Our findings could provide new perspectives for identifying potential prognostic markers within the CBX family in BC. Targeting CBX2 may present a promising approach to address endocrine resistance in BC therapy.

Engineered mesenchymal stem/stromal cells against cancer

Mesenchymal stem/stromal cells (MSCs) have garnered attention for their potential in cancer therapy due to their ability to home to tumor sites. Engineered MSCs have been developed to deliver therapeutic proteins, microRNAs, prodrugs, chemotherapy drugs, and oncolytic viruses directly to the tumor microenvironment, with the goal of enhancing therapeutic efficacy while minimizing off-target effects. Despite promising results in preclinical studies and clinical trials, challenges such as variability in delivery efficiency and safety concerns persist. Ongoing research aims to optimize MSC-based cancer eradication and immunotherapy, enhancing their specificity and efficacy in cancer treatment. This review focuses on advancements in engineering MSCs for tumor-targeted therapy.

Comprehensive Breslow thickness (BT)-based analysis to identify biological mechanisms associated with melanoma pathogenesis

Breslow thickness (BT), a parameter measuring the depth of invasion of abnormally proliferating melanocytes, is a key indicator of melanoma severity and prognosis. However, the mechanisms underlying the increase in BT remain elusive. Utilizing data from The Cancer Genome Atlas (TCGA) human skin cutaneous melanoma (SKCM), we identified a set of BT-related molecules and analyzed their expression and genomic heterogeneity across pan-cancerous and normal tissues. Through consensus clustering, we identified two distinct BT phenotypes in melanoma, which exhibited significant differences in clinical, genomic, and immune infiltration characteristics. High BT molecular expression was associated with reduced CD8+ T cell infiltration and poor immunotherapy response, potentially mediated by the Macrophage Migration Inhibitory Factor (MIF) signaling pathway. In vitro experiments confirmed that BT molecules, including TRIM29, SERPINB5, and RAB25, promoted melanoma development through distinct mechanisms. Notably, fibroblast-derived TRIM29 and B-cell-derived RAB25 interacted with SPP1+ monocytes/macrophages via different pathways. Our findings suggest that genomic variations leading to imbalanced expression of BT molecules across cancers contribute to increased BT, which is closely linked to an immunosuppressive microenvironment. The involvement of multiple cell types and complex intercellular interactions underscores the importance of evaluating dynamic cellular crosstalk in the tumor microenvironment to better understand BT increases and develop more effective immunotherapeutic strategies.

Exploring molecular disparities of H-type vasculature endothelial cells in osteonecrosis of the femoral head through single-cell analysis

OBJECTIVE

Recent studies highlight the role of H-type vasculature in bone regeneration. This study, based on single-cell RNA sequencing (scRNA-seq), aims to explore the changes in H-type vasculature endothelial cells (H_ECs) in osteonecrosis of the femoral head (ONFH) and hip osteoarthritis (HOA), focusing on the death modes such as ferroptosis, pyroptosis, and parthanatos.

METHODS

We re-analyzed the scRNA-seq data of femoral head samples publicly available in 2022. This study selected nine femoral head samples (3 each from HOA, ONFH stage 3 A, and ONFH stage 4). CD31 + EMCN + endothelial cells were classified as H_ECs. Molecular differences were assessed using Gene Ontology and KEGG analysis. Hypoxia, ferroptosis, pyroptosis, and parthanatos indices were calculated, and transcription factors were predicted using SENIC. Cell communication was analyzed with CellChat.

RESULTS

After integrating the 9 samples, 14 cell types were identified: B cells, Mesenchymal stem cells, Osteoblasts, Endothelial cells, Monocytes, T cells, NK cells, Fibroblasts, Macrophages, Common myeloid progenitors, Chondrocytes, Myelocytes, Osteoclasts, and Pericytes. The number of endothelial cells and H_ECs decreased with necrosis severity. H_ECs showed higher angiogenic capacity but lower stress resistance compared to other endothelial cells. Angiogenic capacity decreased in necrotic samples, accompanied by an elevation in inflammation levels. The hypoxia index was higher, with ferroptosis increased in stage 3 A and parthanatos in stages 3 A and 4. No change was observed in pyroptosis. Cell communication analysis revealed downregulation of SLIT3-ROBO4 signaling during necrosis.

CONCLUSION

H_ECs show molecular differences compared to other endothelial cells. Ferroptosis and parthanatos contribute to the demise of H_ECs in ONFH, with pericytes and fibroblasts supporting H_EC angiogenesis.

Neoadjuvant anti-4-1BB confers protection against spontaneous metastasis through low-affinity intratumor CD8 + T cells in triple-negative breast cancer

Neoadjuvant immunotherapy seeks to harness the primary tumor as a source of relevant tumor antigens to enhance systemic anti-tumor immunity through improved immunological surveillance. Despite having revolutionized the treatment of patients with high-risk early-stage triple-negative breast cancer (TNBC), a significant portion of patients remain unresponsive and succumb to metastatic recurrence post-treatment. Here, we found that optimally scheduled neoadjuvant administration of anti-4-1BB monotherapy was able to counteract metastases and prolong survival following surgical resection. Phenotypic and transcriptional profiling revealed enhanced 4-1BB expression on tumor-infiltrating intermediate (T int ), relative to progenitor (T prog ) and terminally exhausted (T term ) T cells. Furthermore, T int was enriched in low-affinity T cells. Treatment with anti-4-1BB drove clonal expansion of T int , with reduced expression of tissue-retention marker CD103 in T prog . This was accompanied by increased TCR clonotype sharing between paired tumors and pre-metastatic lungs. Further interrogation of sorted intratumor T cells confirmed enhanced T cell egress into circulation following anti-4-1BB treatment. In addition, gene signature extracted from anti-4-1BB treated T int was consistently associated with improved clinical outcomes in BRCA patients. Combinatorial neoadjuvant anti-4-1BB and ablation of tumor-derived CXCL16 resulted in enhanced therapeutic effect. These findings illustrate the intratumor changes underpinning the efficacy of neoadjuvant anti-4-1BB, highlighting the reciprocity between local tissue-retention and distant immunologic fortification, suggesting treatment can reverse the siphoning of intratumor T cells to primary tumor, enabling redistribution to distant tissues and subsequent protection against metastases.

Scavenger Receptor CD36 in Tumor-Associated Macrophages Promotes Cancer Progression by Dampening Type-I IFN Signaling

Tumor-associated macrophages (TAM) are a heterogeneous population of myeloid cells that dictate the inflammatory tone of the tumor microenvironment. In this study, we unveiled a mechanism by which scavenger receptor cluster of differentiation 36 (CD36) suppresses TAM inflammatory states. CD36 was upregulated in TAMs and associated with immunosuppressive features, and myeloid-specific deletion of CD36 significantly reduced tumor growth. Moreover, CD36-deficient TAMs acquired inflammatory signatures including elevated type-I IFN (IFNI) production, mirroring the inverse correlation between CD36 and IFNI response observed in patients with cancer. IFNI, especially IFNβ, produced by CD36-deficient TAMs directly induced tumor cell quiescence and delayed tumor growth. Mechanistically, CD36 acted as a natural suppressor of IFNI signaling in macrophages through p38 activation downstream of oxidized lipid signaling. These findings establish CD36 as a critical regulator of TAM function and the tumor inflammatory microenvironment, providing additional rationale for pharmacologic inhibition of CD36 to rejuvenate antitumor immunity. Significance: CD36 in tumor-associated macrophages mediates immunosuppression and can be targeted as a therapeutic avenue for stimulating interferon production and increasing the efficacy of immunotherapy.

CD4+FOXP3Exon2+ regulatory T cell frequency predicts breast cancer prognosis and survival

CD4+FOXP3+ regulatory T cells (Tregs) suppress immune responses to tumors, and their accumulation in the tumor microenvironment (TME) correlates with poor clinical outcome in several cancers, including breast cancer (BC). However, the properties of intratumoral Tregs remain largely unknown. Here, we found that a functionally distinct subpopulation of Tregs, expressing the FOXP3 Exon2 splicing variants, is prominent in patients with hormone receptor-positive BC with poor prognosis. Notably, a comprehensive examination of the TCGA validated FOXP3E2 as an independent prognostic marker in all other BC subtypes. We found that FOXP3E2 expression underlies BCs with defective mismatch repair and a stem-like signature and highlights pathways involved in tumor survival. Last, we found that the TME induces FOXP3E2 through the CXCL12/CXCR4 axis and confirmed the higher immunosuppressive capacity of FOXP3E2+ Tregs derived from patients with BC. Our study suggests that FOXP3E2+ Tregs might be used as an independent biomarker to predict BC prognosis and survival and to develop super-targeted immunotherapies.

Cytokines in cancer

Cytokines are proteins used by immune cells to communicate with each other and with cells in their environment. The pleiotropic effects of cytokine networks are determined by which cells express cytokines and which cells express cytokine receptors, with downstream outcomes that can differ based on cell type and environmental cues. Certain cytokines, such as interferon (IFN)-γ, have been clearly linked to anti-tumor immunity, while others, such as the innate inflammatory cytokines, promote oncogenesis. Here we provide an overview of the functional roles of cytokines in the tumor microenvironment. Although we have a sophisticated understanding of cytokine networks, therapeutically targeting cytokine pathways in cancer has been challenging. We discuss current progress in cytokine blockade, cytokine-based therapies, and engineered cytokine therapeutics as emerging cancer treatments of interest.

Molecular and cellular dynamics of squamous cell carcinomas across tissues

Squamous cell carcinomas (SCCs), arising from the skin, head and neck, lungs, esophagus, and cervix, are collectively among the most common cancers and a frequent cause of cancer morbidity and mortality. Despite distinct stratified epithelial tissues of origin, converging evidence points toward shared biologic pathways across SCCs. With recent breakthroughs in molecular technologies have come novel SCC treatment paradigms, including immunotherapies and targeted therapy. This review compares commonalities and differences across SCCs from different anatomical sites, including risk factors and genetics, as well as cellular and molecular programs driving tumorigenesis. We review landmark discoveries of the "cancer stem cells" (CSCs) that initiate and propagate SCCs and their gene and translational regulation programs. This has led to an appreciation that interactions between CSCs and the immune system play key roles in invasion and therapeutic resistance. Here, we review the unifying principles of SCCs that have emerged from these exciting advances in our understanding of these epithelial cancers.

Convergent inducers and effectors of T cell paralysis in the tumour microenvironment

Tumorigenesis embodies the formation of a heterotypic tumour microenvironment (TME) that, among its many functions, enables the evasion of T cell-mediated immune responses. Remarkably, most TME cell types, including cancer cells, fibroblasts, myeloid cells, vascular endothelial cells and pericytes, can be stimulated to deploy immunoregulatory programmes. These programmes involve regulatory inducers (signals-in) and functional effectors (signals-out) that impair CD8+ and CD4+ T cell activity through cytokines, growth factors, immune checkpoints and metabolites. Some signals target specific cell types, whereas others, such as transforming growth factor-β (TGFβ) and prostaglandin E2 (PGE2), exert broad, pleiotropic effects; as signals-in, they trigger immunosuppressive programmes in most TME cell types, and as signals-out, they directly inhibit T cells and also modulate other cells to reinforce immunosuppression. This functional diversity and redundancy pose a challenge for therapeutic targeting of the immune-evasive TME. Fundamentally, the commonality of regulatory programmes aimed at abrogating T cell activity, along with paracrine signalling between cells of the TME, suggests that many normal cell types are hard-wired with latent functions that can be triggered to prevent inappropriate immune attack. This intrinsic capability is evidently co-opted throughout the TME, enabling tumours to evade immune destruction.

Regulation of the Cilia as a Potential Treatment for Senescence and Tumors: A Review

Millions of people worldwide die from malignant tumors every year, and the current clinical treatment is still based on radiotherapy and chemotherapy. Immunotherapy-adjuvant chemotherapy is widely applied, yet resistance to various factors persists in the management of advanced malignancies. Recently researchers have gradually discovered that the integrity of primary cilia is closely related to many diseases. The phenotypic changes in primary cilia are found in some cases of progeria, tumorigenesis, and drug resistance. Primary cilia seem to mediate signaling during these diseases. Hedgehog inhibitors have emerged in recent years to treat tumors by controlling signaling proteins on primary cilia. There is evidence for the use of anti-tumor drugs to treat senescence-related disease. Considering the close relationship between aging and obesity, as well as the obesity is the phenotype of many ciliopathies. Therefore, we speculate that some anti-tumor or anti-aging drugs can treat ciliopathies. Additionally, there is evidence suggesting that anti-aging drugs for tumor treatment, in which the process may be mediated by cilia. This review elucidates for the first time that cilia may be involved in the regulation of senescence, metabolic, tumorigenesis, and tumor resistance and hypothesizes that cilia can be regulated to treat these diseases in the future.

RAC2 as a Tumor-Suppressive Biomarker Associated with T Cell Infiltration in Breast Cancer

Background: RAC2 is critical in regulating the homeostasis of hematopoietic stem cells. Nonetheless, its role in breast cancer (BC) remains unclear, necessitating further investigation. Methods: The expression of RAC2 in BC and healthy tissues was acquired from The Cancer Genome Atlas. Its validity was further assessed using datasets from the gene expression omnibus database. The Tumor Immune Single-cell Hub database was used to collect and analyze the single-cell RNA sequencing datasets of BC. The diagnostic relevance of RAC2 was evaluated using receiver operating characteristic curves. Further assessment was carried out via enrichment analyses; Gene Set Analysis, immune scoring, single-cell sequencing, and immunohistochemical analysis were conducted to confirm the relationship between RAC2 expression and immune infiltration. Results: RAC2 expression was notably heightened in BC (p < 0.001). It was observed that a better prognosis was linked to heightened expression of RAC2 (p < 0.01), with the diagnostic efficacy of the marker noted to be good (area under the curve = 0.858). We found a lower percentage of protumor immune cells and a greater proportion of antitumor immune cells in the high RAC2. Our analysis revealed alterations in gene expression and an enriched network of immune pathways influenced by RAC2. Notably, cytotoxic genes, chemokines, chemokine receptors, immunostimulators, and immunosuppressive molecules positively correlated with RAC2 expression. RAC2 expression reliably predicted how patients would respond to two different therapeutic approaches in BC. Conclusions: The RAC2 was found to be a key biomarker in BC in the current study, demonstrating considerable potential as a prognostic and diagnostic marker. These results highlight the RAC2 potential to improve precision medicine strategies and treatment outcomes for patients with BC.

Stemness in solid malignancies: coping with immune attack

Immunotherapy has become a key new pillar of cancer treatment, and this has sparked interest in understanding mechanisms of cancer immune evasion. It has long been appreciated that cancers are constituted by heterogeneous populations of tumour cells. This feature is often fuelled by specialized cells that have molecular programs resembling tissue stem cells. Although these cancer stem cells (CSCs) have capacity for unlimited self-renewal and differentiation, it is increasingly evident that some CSCs are capable of achieving remarkable immune resistance. Given that most immunotherapy regiments have overlooked CSC-specific immune-evasive mechanisms, many current treatment strategies often lead to cancer relapse. This Review focuses on advancements in understanding how CSCs in solid tumours achieve their unique immune-evasive properties, enabling them to drive tumour regrowth. Moreover, as cancers often arise from tissue stem cells that acquired oncogenic mutations, we discuss how tissue stem cells undergoing malignant transformation activate intrinsic immune-evasive mechanisms and establish close interactions with suppressive immune cells to escape immune surveillance. In addition, we summarize how in advanced disease stages, CSCs often hijack features of normal stem cells to resist antitumour immunity. Finally, we provide insights in how to design a new generation of cancer immunotherapies to ensure elimination of CSCs.

Targeting AURKA with multifunctional nanoparticles in CRPC therapy

Castration-resistant prostate cancer (CRPC) presents significant therapeutic challenges due to its aggressive nature and poor prognosis. Targeting Aurora-A kinase (AURKA) has shown promise in cancer treatment. This study investigates the efficacy of ART-T cell membrane-encapsulated AMS@AD (CM-AMS@AD) nanoparticles (NPs) in a photothermal-chemotherapy-immunotherapy combination for CRPC. Bioinformatics analysis of the Cancer Genome Atlas-prostate adenocarcinoma (TCGA-PRAD) dataset revealed overexpression of AURKA in PCa, correlating with poor clinical outcomes. Single-cell RNA sequencing data from the GEO database showed a significant reduction in immune cells in CRPC. Experimentally, T cell membrane-biomimetic NPs loaded with the AURKA inhibitor Alisertib and chemotherapy drug DTX were synthesized and characterized by dynamic light scattering and transmission electron microscopy, showing good stability and uniformity (average diameter: 158 nm). In vitro studies demonstrated that these NPs inhibited CRPC cell proliferation, increased the G2/M cell population, and elevated apoptosis, confirmed by γH2AX expression. In vivo, CM-AMS@AD NPs accumulated in tumor tissues, significantly slowed tumor growth, decreased proliferation, increased apoptosis, and improved the immune environment, enhancing dendritic cell (DC) maturation and increasing CD8 + /CD4 + ratios. These findings suggest that CM-AMS@AD NPs offer a promising triple-combination therapy for CRPC, integrating photothermal, chemotherapy, and immunotherapy, with significant potential for future clinical applications.

Turning attention to tumor-host interface and focus on the peritumoral heterogeneity of glioblastoma

Approximately 90% of glioblastoma recurrences occur in the peritumoral brain zone (PBZ), while the spatial heterogeneity of the PBZ is not well studied. In this study, two PBZ tissues and one tumor tissue sample are obtained from each patient via preoperative imaging. We assess the microenvironment and the characteristics of infiltrating immune/tumor cells using various techniques. Our data indicate there are one or more regions with higher cerebral blood flow in PBZ, which we collectively name the "higher cerebral blood flow interface" (HBI). The HBI exhibited more neovascularization than the "lower cerebral blood flow interfaces" (LBI). The HBI tend to have increased infiltration of macrophages and T lymphocytes infiltration compared with that in LBI. There are more tumor cells in the HBI than in LBI, with substantial differences in the gene expression profiles of these tumor cells. HBI may be the key area of PBZ-targeting therapy after surgical resection.

Hyaluronic acid-functionalized supramolecular nanophotosensitizers for targeted photoimmunotherapy of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is recognized as a particularly aggressive subtype of breast cancer that is devoid of effective therapeutic targets. Immune checkpoint inhibitors (ICIs) have demonstrated promising results in TNBC treatment. Nonetheless, most patients either develop resistance to ICIs or fail to respond to them initially. Owing to its spatio-temporal precision and non-invasive nature, photoimmunotherapy offers a targeted therapeutic strategy for TNBC. Herein, we report hyaluronic acid (HA)-functionalized indocyanine green-based supramolecular nanoparticles (HGI NPs), with biodegradable characteristics, for high-performance photoacoustic imaging and targeted phototherapy for TNBC. Notably, HGI NPs can significantly gather in TNBC tissues because of the enhanced permeability and retention effect of the tumor, and the tumor-targeting properties of HA. The strong amplification of HGI nanoparticles triggers a significant immunogenic cell death (ICD) response when exposed to 808 nm light, thus shifting the immunosuppressive tumor microenvironment (iTME) into a tumor attack mode and 'hot' state. Antitumor experiments demonstrate the high efficiency of the supramolecular photosensitizers HGI NPs for TNBC elimination and good biosafety. This synergistic strategy reshapes the iTME and amplifies the antitumor immune response, providing a theoretical foundation for combining phototherapy and ICIs as potential treatments for TNBC.

Spatial transcriptomics in breast cancer: providing insight into tumor heterogeneity and promoting individualized therapy

A comprehensive understanding of tumor heterogeneity, tumor microenvironment and the mechanisms of drug resistance is fundamental to advancing breast cancer research. While single-cell RNA sequencing has resolved the issue of "temporal dynamic expression" of genes at the single-cell level, the lack of spatial information still prevents us from gaining a comprehensive understanding of breast cancer. The introduction and application of spatial transcriptomics addresses this limitation. As the annual technical method of 2020, spatial transcriptomics preserves the spatial location of tissues and resolves RNA-seq data to help localize and differentiate the active expression of functional genes within a specific tissue region, enabling the study of spatial location attributes of gene locations and cellular tissue environments. In the context of breast cancer, spatial transcriptomics can assist in the identification of novel breast cancer subtypes and spatially discriminative features that show promise for individualized precise treatment. This article summarized the key technical approaches, recent advances in spatial transcriptomics and its applications in breast cancer, and discusses the limitations of current spatial transcriptomics methods and the prospects for future development, with a view to advancing the application of this technology in clinical practice.

Combined Autophagy Inhibition and Dendritic Cell Recruitment Induces Antitumor Immunity and Enhances Immune Checkpoint Blockade Sensitivity in Pancreatic Cancer

The effect of immune checkpoint inhibitors is extremely limited in patients with pancreatic ductal adenocarcinoma (PDAC) due to the suppressive tumor immune microenvironment. Autophagy, which has been shown to play a role in antitumor immunity, has been proposed as a therapeutic target for PDAC. In this study, single-cell RNA sequencing of autophagy-deficient murine PDAC tumors revealed that autophagy inhibition in cancer cells induced dendritic cell (DC) activation. Analysis of human PDAC tumors substantiated a negative correlation between autophagy and DC activation signatures. Mechanistically, autophagy inhibition increased the intracellular accumulation of tumor antigens, which could activate DCs. Administration of chloroquine, an autophagy inhibitor, in combination with Flt3 ligand-induced DC infiltration inhibited tumor growth and increased tumor-infiltrating T lymphocytes. However, autophagy inhibition in cancer cells also induced CD8+ T-cell exhaustion with high expression of immune checkpoint LAG3. A triple-therapy comprising chloroquine, Flt3 ligand, and an anti-LAG3 antibody markedly reduced tumor growth in orthotopic syngeneic PDAC mouse models. Thus, targeting autophagy in cancer cells and activating DCs sensitize PDAC tumors to immune checkpoint inhibitor therapy, warranting further development of this treatment approach to overcome immunosuppression in pancreatic cancer. Significance: Inhibiting autophagy in pancreatic cancer cells enhances intracellular accumulation of tumor antigens to induce dendritic cell activation and synergizes with immunotherapy to markedly inhibit the growth of pancreatic ductal adenocarcinoma.

Cancer Cells in Sleep Mode: Wake Them to Eliminate or Keep Them Asleep Forever?

Cancer cell dormancy is a critical phase in cancer development, wherein cancer cells exist in a latent state marked by temporary but reversible growth arrest. This dormancy phase contributes to anticancer drug resistance, cancer recurrence, and metastasis. Treatment strategies aimed at cancer dormancy can be categorized into two contradictory approaches: inducing cancer cells into a dormant state or eliminating dormant cells. While the former seeks to establish permanent dormancy, the latter aims at eradicating this small population of dormant cells. In this review, we explore the current advancements in therapeutic methods targeting cancer cell dormancy and discuss future strategies. The concept of cancer cell dormancy has emerged as a promising avenue for novel cancer treatments, holding the potential for breakthroughs in the future.

B cells spatial organization defines their phenotype and function in cancer "Tell me with whom you consort, and I will tell you who you are" - Goethe

The presence of B cells and their subtypes in the tumor environment has been recognized a for very long time. Immunoglobulins specific for more than thousands of tumor-associated antigens were detected in the sera of patients with cancer; however, antibody-mediated cancer cell killing is usually impaired. The role of humoral immune response remained elusive until recently, with new discoveries regarding their contribution in regulating antitumor immunity, particularly during immunotherapy. Humoral immunity has been described to promote or attenuate tumorigenesis and can have opposing effects on therapeutic outcome in different tumor entities. The antagonism effect of B cells depends on their subtypes and immunoglobulin isotypes and is regulated by their spatial distribution and localization. In this short review, we will focus on how the spatial organization of B cells within the tumor microenvironment, tumor-associated lymph nodes, and tertiary lymphoid structures define their fate and function and contribute to the regulation of antitumor immunity.

Cell-cell interactions mediating primary and metastatic breast cancer dormancy

Breast cancer remains one of the leading causes of death in women around the world. A majority of deaths from breast cancer occur due to cancer cells colonizing distant organ sites. When colonizing these distant organ sites, breast cancer cells have been known to enter into a state of dormancy for extended periods of time. However, the mechanisms that promote dormancy as well as dormant-to-proliferative switch are not fully understood. The tumor microenvironment plays a key role in mediating cancer cell phenotype including regulation of the dormant state. In this review, we highlight cell-cell interactions in the tumor microenvironment mediating breast cancer dormancy at the primary and metastatic sites. Specifically, we describe how immune cells from the lymphoid lineage, tumor-associated myeloid lineage cells, and stromal cells of non-hematopoietic origin as well as tissue resident stromal cells impact dormancy vs. proliferation in breast cancer cells as well as the associated mechanisms. In addition, we highlight the importance of developing model systems and the associated considerations that will be critical in unraveling the mechanisms that promote primary and metastatic breast cancer dormancy mediated via cell-cell interactions.

Effects of virus-induced immunogenic cues on oncolytic virotherapy

Oncolytic virotherapy is a promising form of cancer treatment that uses viruses to infect and kill cancer cells. In addition to their direct effects on cancer cells, the viruses stimulate various immune responses partly directed against the tumour. Efforts are made to genetically engineer oncolytic viruses to enhance their immunogenic potential. However, the interplay between tumour growth, viral infection, and immune responses is complex and not fully understood, leading to variable and sometimes counterintuitive therapeutic outcomes. Here, we employ a spatio-temporal model to shed more light on this interplay. We investigate systematically how the properties of virus-induced immunogenic signals (their half-life, rate of spread, and potential to promote T-cell-mediated cytotoxicity) affect the therapeutic outcome. Our simulations reveal that strong immunogenic signals, combined with faster diffusion rates, improve the spread of immune activation, leading to better tumour eradication. However, replicate simulations suggest that the outcome of virotherapy is more stochastic than generally appreciated. Our model shows that virus-induced immune responses can interfere with virotherapy, by targeting virus-infected cancer cells and/or by impeding viral spread. In the presence of immune responses, the mode of virus introduction is important, with systemic viral delivery throughout the tumour yielding the most favourable outcomes. The timing of virus introduction also plays a critical role; depending on the efficacy of the immune response, a later start of virotherapy can be advantageous. Overall, our results emphasise that the rational design of oncolytic viruses requires optimising virus-induced immunogenic signals and strategies that balance viral spread with immune activity for improved therapeutic success.

Tracing Quiescent Cancer Cells In Vivo

QCCs have long gained significant interest as potential "seeds" for recurrent cancers. Clinical evidence suggests that a subset of cancer cells exits the cell cycle and enters a quiescent state following anti-cancer treatment. These microscopic-residual QCCs are extremely challenging to trace and detect within patients. Additionally, QCCs resist conventional anti-cancer therapies due to the lack of cell activity. Notably, upon the unknown environmental cues in unknown time points, sometimes decades later, QCCs can reactivate, triggering cancer relapse at primary or secondary sites. Currently, no targeted therapies or diagnostic tools exist for QCCs, and their molecular regulatory mechanisms remain largely unknown. The major challenge in understanding QCCs lies in the limited availability of human-relevant pre-clinical models that trace and collect QCCs in vivo. This review provides an overview of existing QCC tracing systems and analyzes their limitations. It also cautiously proposes potential improvements for tracing QCCs in vivo based on recent advancements in QCC studies and lineage-tracing techniques. Developing human-relevant and easily accessible in vivo tracing systems will be a crucial step in advancing QCC diagnostics and therapeutic strategies.

The hallmarks of cancer immune evasion

According to the widely accepted "three Es" model, the host immune system eliminates malignant cell precursors and contains microscopic neoplasms in a dynamic equilibrium, preventing cancer outgrowth until neoplastic cells acquire genetic or epigenetic alterations that enable immune escape. This immunoevasive phenotype originates from various mechanisms that can be classified under a novel "three Cs" conceptual framework: (1) camouflage, which hides cancer cells from immune recognition, (2) coercion, which directly or indirectly interferes with immune effector cells, and (3) cytoprotection, which shields malignant cells from immune cytotoxicity. Blocking the ability of neoplastic cells to evade the host immune system is crucial for increasing the efficacy of modern immunotherapy and conventional therapeutic strategies that ultimately activate anticancer immunosurveillance. Here, we review key hallmarks of cancer immune evasion under the "three Cs" framework and discuss promising strategies targeting such immunoevasive mechanisms.

Deconstructing inflammatory memory across tissue set points using cell circuit motifs

Tissue ecosystems are cellular communities that maintain set points through a network of intercellular interactions. We position health and chronic inflammatory disease as alternative stable set points that are (1) robust to perturbation and (2) capable of adaptation and memory. Inflammatory memory, which is the storage of prior experience to durably influence future responsiveness, is central to how tissue ecosystems may be pushed past tipping points that stabilize disease over health. Here, we develop a reductionist framework of circuit motifs that recur in tissue set points. In type 2 immunity, we distinctly find the emergence of 2-cell positive feedback motifs. In contrast, directional motif relays and 3-cell networks feature more prominently in type 1 and 17 responses. We propose that these differences guide the ecologic networks established after surpassing tipping points and associate closely with therapeutic responsiveness. We highlight opportunities to improve our current knowledge of how circuit motifs interact when building toward tissue-level networks across adaptation and memory. By developing new tools for circuit motif nomination and applying them to temporal profiling of tissue ecosystems, we hope to dissect the stability of the chronic inflammatory set point and open therapeutic avenues for rewriting memory to restore health.

Epigenetic control of immunoevasion in cancer stem cells

Cancer stem cells (CSCs) are a poorly differentiated population of malignant cells that (at least in some neoplasms) is responsible for tumor progression, resistance to therapy, and disease relapse. According to a widely accepted model, all stages of cancer progression involve the ability of neoplastic cells to evade recognition or elimination by the host immune system. In line with this notion, CSCs are not only able to cope with environmental and therapy-elicited stress better than their more differentiated counterparts but also appear to better evade tumor-targeting immune responses. We summarize epigenetic modifications of DNA and histones through which CSCs evade immune recognition or elimination, and propose that such alterations constitute promising therapeutic targets to increase the sensitivity of some malignancies to immunotherapy.

Quiescent cancer cells induced by high-density cultivation reveals cholesterol-mediated survival and lung metastatic traits

BACKGROUND

The metastatic cascade, a multifaceted and highly aggressive process, is the primary cause of mortality. The survival of quiescent cancer cells in circulatory system during metastasis is crucial, yet our comprehension is constrained by the absence of universally accepted quiescent cancer models.

METHOD

We developed a quiescent cancer cell model using high-density cultivation. Based on the scRNA-seq analysis, IP-MS, metabolomics, mouse lung metastasis models, cholesterol assay, PLA and other molecular experiments, we explored the molecular mechanism. Immunofluorescence, atomic force microscope, FluidFM, and shear stress stimulation were used to analyze the cytoskeleton and membrane properties contributing to mechanical force resistance.

RESULT

We established a quiescent cancer cell model induced by high-density cultivation. Single-cell RNA sequencing (scRNA-seq) analysis reveals that CDC25A plays a crucial role in the transition to quiescence, with its expression significantly elevated in the quiescent state. Depletion of CDC25A leads to an increased proliferative capacity, and reduced metastasis under high-density conditions. Mechanistically, upregulated CDC25A in quiescent cells enhances cholesterol metabolism via endosome pathways, leading to cell cycle arrest. This increase in cholesterol reinforces the cytoskeleton, alters membrane properties, and improves resistance to mechanical forces in circulatory system.

CONCLUSION

CDC25A significantly increased the cholesterol metabolism through endosome pathway in quiescent cancer cells, leading to the significant changes in cytoskeleton and membrane properties so as to enhance the resistance of mechanical force in circulatory system, facilitating lung metastasis. In high-density cultivation, quiescent cancer cells, up-regulate cholesterol metabolism by CDC25A through endosome pathway, enhancing the resistance to mechanical force in circulatory system, facilitating lung metastasis.

Novel Photo-STING Agonists Delivered by Erythrocyte Efferocytosis-Mimicking Pattern to Repolarize Tumor-Associated Macrophages for Boosting Anticancer Immunotherapy

Immunotherapy has emerged as a highly effective therapeutic strategy for cancer treatment. Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon gene (STING) pathway activation facilitates tumor-associated macrophage (TAM) polarization toward M1 phenotype, and Mn2+ are effective agents for this pathway activation. However, the high in vivo degradation rate and toxicity of Mn2+ hamper clinical application of immunotherapy. Here, this work has newly synthesized and screened manganese porphyrins for Mn2+ transport, referred to as photo-STING agonists (PSAs), and further encapsulate them into core-shell nanoparticles named Rm@PP-GA with dual specificity for tumor tissue and TAMs. Not only do PSAs achieve higher Mn2+ delivery efficiency compared to Mn2+, but they also generate reactive oxygen species under light exposure, promoting mitochondrial DNA release for cGAS-STING pathway activation. In Rm@PP-GA, globin and red blood cell membranes (Rm) are used for erythrocyte efferocytosis-mimicking delivery. Rm can effectively prolong the in vivo circulation period while globin enables PSAs to be taken up by TAMs via CD163 receptors. After Rm rupture mediated by perfluorohexane in nanoparticles under ultrasonication, drugs are specifically released for TAM repolarization. Further, dendritic cells mature, as well as T lymphocyte infiltrate, both of which favor tumor eradication. Therefore, cancer immunotherapy is optimized by novel PSAs delivered by erythrocyte efferocytosis-mimicking delivery pattern.