MYC promotes immune-suppression in triple-negative breast cancer via inhibition of interferon signaling

Harnessing STING Signaling and Natural Killer Cells Overcomes PARP Inhibitor Resistance in Homologous Recombination-Deficient Breast Cancer

Homologous recombination deficiency (HRD) contributes to genomic instability and leads to sensitivity to PARP inhibitors (PARPi). HRD also activates the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-interferon pathway, highlighting the need to understand the impact of cGAS-STING-IFN signaling on PARPi efficacy. In this study, we analyzed a cohort of 35 breast cancer patient-derived xenografts and mouse-derived allografts. PARPi sensitivity correlated with HRD, increased genomic instability, and activation of the cGAS-STING-IFN signaling pathway. Single-cell analyses showed that IFN signaling and IFN-based immune interactions were suppressed in preclinical models with acquired resistance to PARPi, lacking concomitant clonal expansion of functional CD8+ T cells. However, the combination of a PARPi and a novel STING agonist (STINGa) increased immune infiltration and resulted in superior antitumor activity in these tumors. Notably, the efficacy of PARPi monotherapy and the combination treatment with a STINGa was dependent on natural killer (NK) cells. In agreement, patients with breast cancer with BRCA1/BRCA2 mutations and good responses to PARPi showed higher abundancy of CD56+ NK cells in the tumor microenvironment and treatment-engaged CD56bright NK cells in the peripheral immune compartment, compared with those with poor responses. Therefore, these findings propose the combination of PARPis and a STINGa as a potential novel strategy to enhance the therapeutic response in patients with acquired PARPi resistance and highlight a pivotal role of NK cells in the PARPi antitumor activity. Significance: PARP inhibitor sensitivity is associated with cGAS-STING-IFN signaling, which can be harnessed by combining PARP inhibitors with STING agonists to overcome acquired resistance and requires NK cells to mediate antitumor immunity. See related commentary by Gohari et al., p. 1747.

GATA3 differentially regulates the transcriptome via zinc finger 2-modulated phase separation

Phase separation (PS) underlies gene control by transcription factors. However, little is known about whether and how DNA-binding domains (DBDs) regulate the PS for transcription factors to differentially regulate the transcriptome. The transcription factor GATA3, a master immune regulator, is frequently mutated in breast cancer. Here, we report that GATA3 undergoes DBD-modulated PS to mediate the formation of chromatin condensates. We show that the DBD regulates the GATA3 PS through its zinc finger 2 (ZnF2) domain, which provides positive charges for multivalent electrostatic interactions mainly via two arginine amino acids, R329 and R330. Compared with breast-cancer-associated GATA3 without ZnF2-defective mutations, breast cancer GATA3 with ZnF2-defective mutations causes aberrant ZnF2-modulated PS and condensate formation to remodel the differentially regulated transcriptome, resulting in a favorable prognosis for patients and reduced tumor growth in mice. Therefore, GATA3 demonstrates a principle of how a transcription factor differentially regulates the transcriptome via DBD-modulated PS.

PDCD11 Stabilizes C-MYC Oncoprotein by Hindering C-MYC-SKP2 Negative Feedback Loop to Facilitate Progression of p53-Mutant Breast and Colon Malignancies

C-MYC is a proto-oncoprotein whose dysregulation triggers tumorigenesis and tumor progression in ≈70% of cancer cases. It is presently demonstrated that aberrantly upregulated MYC is caused by the overexpressed and "extra-nucleolar" PDCD11 in p53-mutant breast and colon cancer cells, which is highly correlated to tumor progression, metastasis, and recurrence. In the nucleoplasm, PDCD11 binds to the TAD of C-MYC to prevent SKP2, a transcriptional target of C-MYC as well as one of the major E3 ligase components targeting C-MYC, from interacting with and ubiquitinating C-MYC in feedback. The ensuing stabilized C-MYC activates downstream signaling to facilitate the cellular G1/S transition, proliferation, and migration. PDCD11 silencing restores SKP2-mediated C-MYC degradation, thereby remarkably suppressing tumor growth and metastasis in nude mice. These findings highlight PDCD11 as a novel C-MYC partner and thereby offer a potential therapeutic rationale to challenge PDCD11-mediated "pro-stabilization" effect on C-MYC, a widely considered "undruggable" target, to combat C-MYC-driven malignancies with p53 mutation.

TME-responsive nanocomposite hydrogel with targeted capacity for enhanced synergistic chemoimmunotherapy of MYC-amplified osteosarcoma

The oncogene MYC is one of the most commonly activated oncogenic proteins in human tumors, with nearly one-fourth of osteosarcoma showing MYC amplification and exhibiting the worst clinical outcomes. The clinical efficacy of single radiotherapy, chemotherapy, and immunotherapy for such osteosarcoma is poor, and the dysregulation of MYC amplification and immune-suppressive tumor microenvironment (TME) may be potential causes of anti-tumor failure. To address the above issues, we developed an injectable TME-responsive nanocomposite hydrogel to simultaneously deliver an effective MYC inhibitor (NHWD-870) and IL11Rα-targeted liposomes containing cisplatin-loaded MnO2 (Cis/Mn@Lipo-IL11). After in situ administration, NHWD-870 effectively degrades MYC and downregulates CCL2 and IL13 cytokines to trigger M1 type activation of macrophages. Meanwhile, targeted delivery of Cis/Mn@Lipo-IL11 reacts with excess intratumoral GSH to generate Mn2+ and thus inducing excess active oxygen species (ROS) production through Fenton-like reaction, along with cisplatin, thereby inducing immunogenic cell death (ICD) to promote dendritic cell maturation. Through synergistic regulation of MYC and ICD levels, the immune microenvironment was reshaped to enhance immune infiltration. In the osteosarcoma-bearing model, the nanocomposite hydrogel significantly enhanced tumor T cell infiltration, induced effective anti-tumor immunity and attenuated lung metastasis. Therefore, our results reveal a powerful strategy for targeted combination therapy of MYC-amplified osteosarcoma.

Lipid Peroxidation and Type I Interferon Coupling Fuels Pathogenic Macrophage Activation Causing Tuberculosis Susceptibility

A quarter of human population is infected with Mycobacterium tuberculosis, but less than 10% of those infected develop pulmonary TB. We developed a genetically defined sst1-susceptible mouse model that uniquely reproduces a defining feature of human TB: the development of necrotic lung granulomas and determined that the sst1-susceptible phenotype was driven by the aberrant macrophage activation. This study demonstrates that the aberrant response of the sst1-susceptible macrophages to prolonged stimulation with TNF is primarily driven by conflicting Myc and antioxidant response pathways leading to a coordinated failure 1) to properly sequester intracellular iron and 2) to activate ferroptosis inhibitor enzymes. Consequently, iron-mediated lipid peroxidation fueled Ifn-beta superinduction and sustained the Type I Interferon (IFN-I) pathway hyperactivity that locked the sst1-susceptible macrophages in a state of unresolving stress and compromised their resistance to Mtb. The accumulation of the aberrantly activated, stressed, macrophages within granuloma microenvironment led to the local failure of anti-tuberculosis immunity and tissue necrosis. The upregulation of Myc pathway in peripheral blood cells of human TB patients was significantly associated with poor outcomes of TB treatment. Thus, Myc dysregulation in activated macrophages results in an aberrant macrophage activation and represents a novel target for host-directed TB therapies.

Active Substances from the Micro-Immunotherapy Medicine 2LC1® Show In Vitro Anti-Cancer Properties in Colon, Prostate, and Breast Cancer Models and Immune-Enhancing Capabilities in Human Macrophages

Tumor-associated macrophages (TAMs) play a pivotal role in cancer regulation by influencing tumor growth, metastasis, and the immune microenvironment. By providing low doses and ultra-low doses (ULD) of immune regulators to the organism, micro-immunotherapy (MI) medicines (MIM) could be seen as valuable adjuvant drugs in the context of a wide range of pathological conditions, including cancers. Thus, these MIM could target TAMs, affecting their phenotype and activities. In this study, the anti-tumor and the immune-stimulatory effects of four capsules out of the ten composing the Labo'life's MIM 2LC1® (2LC1-1, 2LC1-6, 2LC1-7, and 2LC1-8), as well as the specific nucleic acid (SNA®) sequence SNA-MYC present at ULD in this medicine have been evaluated in vitro, in several cancer models, and in human monocyte-derived macrophages. Our results showed that the tested MI formulations increased the tumor cell death of spheroids from HCT-116 colon cancer cells, while reducing the spheroid volume. Moreover, the treatments impaired the clonogenic capabilities of two cancer cell lines from epithelial origin, the LNCaP prostate cancer and the MCF-7 breast cancer cells. Interestingly, ULD of the SNA-MYC shared similar anti-cancer capabilities in those models, and it led to a significant reduction in the expression of C-MYC when evaluated in a model of human M2 macrophages. In the same model, the MI formulations also increased the expression of CD86 and HLA-DR, two markers of M1 anti-tumor macrophages. In addition, the tested items modulated the secretion of a panel of chemokines related to macrophage activity and immune cell recruitment. Finally, our results showed that 2LC1-8 increased the phagocytosis capabilities of human monocyte-derived macrophages, thus possibly contributing to sustaining the immune functions of M1, which are crucial in the context of cancer. Even if more research is needed to uncover their exact mechanism of action, these results suggest that the tested capsules of 2LC1 as well as ULD of SNA-MYC display both anti-tumor and immune-enhancing effects.

MYC controls STING levels to downregulate inflammatory signaling in breast cancer cells upon DNA damage

Amplification of the MYC proto-oncogene is frequently observed in various cancer types, including triple negative breast cancer (TNBC). Emerging evidence suggests that suppression of local anti-tumor immune responses by MYC, at least in part, explains the tumor-promoting effects of MYC. Specifically, MYC upregulation was demonstrated to suppress the tumor-cell intrinsic activation of a type I IFN response and thereby hamper innate inflammatory signaling, which may contribute to the disappointing response to immunotherapy in patients with TNBC. In this study, we show that MYC interferes with protein expression and functionality of the STING pathway. MYC-mediated STING downregulation in BT-549 and MDA-MB-231 triple-negative breast cancer cell lines require the DNA binding ability of MYC, and is independent of binding of MYC to its co-repressor MIZ1. Both STAT1 and STAT3 promote the steady-state expression levels of STING, and STAT3 cooperates with MYC in regulating STING. Conversely, MYC-mediated downregulation of STING affects protein levels of STAT1 and downstream chemokine production. Furthermore, we show that MYC overexpression hampers immune cell activation triggered by DNA damage through etoposide or irradiation treatment, and specifically impedes the activation of natural killer cells. Collectively, these results show that MYC controls STING levels and thereby regulates tumor cell-intrinsic inflammatory signaling. These results contribute to our understanding of how MYC suppresses inflammatory signaling in TNBC, and may explain why a large fraction of patients with TNBC do not benefit from immunotherapy.

Recent Progress and Potential of G4 Ligands in Cancer Immunotherapy

G-quadruplex (G4) structures are non-canonical nucleic acid conformations that play crucial roles in gene regulation, DNA replication, and telomere maintenance. Recent studies have highlighted G4 ligands as promising anticancer agents due to their ability to modulate oncogene expression and induce DNA damage. By stabilizing G4 structures, these ligands affect tumor progression. Additionally, they have been implicated in tumor immunity modulation, particularly through the activation and immunogenic cell death induction of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway. Moreover, their disruption of telomere maintenance and regulation of key oncogenes, such as c-MYC and KRAS, position them as candidates for immune-based therapeutic interventions. Despite their therapeutic potential, challenges remain in optimizing their clinical applications, particularly in patient stratification and elucidating their immunomodulatory effects. This review provides a comprehensive overview of the mechanisms through which G4 ligands influence tumor progression and immune regulation, highlighting their potential role in future cancer immunotherapy strategies.

Immune evasion and resistance in breast cancer

Breast cancer (BC) is the most common malignancy in females with an increasing incidence in the last decade. The previously observed decline in BC mortality rates has also slowed down recently with an increase in the incidence of invasive BC. BC has various molecular subtypes. Among these subtypes, triple-negative breast cancer (TNBC) represents the most aggressive BC, with a poor prognosis. Because lack of the hormonal or human epidermal growth factor receptor 2 (HER2) receptors, TNBC is resistant to hormonal and HER2 targeted therapy effective for other BC subtypes. The good news is that TNBC has recently been considered an immunologically 'hot' tumor. Therefore, immunotherapy, particularly immune checkpoint inhibitor therapy, represents a promising therapeutic approach TNBC. However, a considerable percentage of patients with TNBC do not respond well to immunotherapy, indicating that TNBC seems to adopt several mechanisms to evade immune surveillance. Thus, it is crucial to investigate the mechanisms underlying TNBC immune evasion and resistance to immunotherapy. In this review, we examine and discuss the most recently discovered mechanisms for BC, with a particular focus on TNBC, to evade the immune surveillance via kidnapping the immune checkpoints, suppressing the immune responses in tumor microenvironment and inhibiting the tumor antigen presentation. Evaluation of these mechanisms in BC will hopefully guide future immunotherapeutic research and clinical trials.

Practical microenvironment classification in diffuse large B cell lymphoma using digital pathology

Diffuse large B cell lymphoma (DLBCL) is a heterogeneous B cell neoplasm with variable clinical outcomes influenced by both tumor-derived and lymphoma microenvironment (LME) alterations. A recent transcriptomic study identifies four DLBCL subtypes based on LME characteristics: germinal center (GC)-like, mesenchymal (MS), inflammatory (IN), and depleted (DP). However, integrating this classification into clinical practice remains challenging. Here, we utilize deconvolution methods to assess microenvironment component abundance, establishing an LME classification of DLBCL using immunohistochemistry markers and digital pathology based on CD3, CD8, CD68, PD-L1, and collagen. This staining-based algorithm demonstrates over 80% concordance with transcriptome-based classification. Single-cell sequencing confirms that the immune microenvironments distinguished by this algorithm align with transcriptomic profiles. Significant disparities in overall and progression-free survival are observed among LME subtypes following rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or R-CHOP with targeted agents (R-CHOP-X) immunochemotherapy. LME subtypes differed from distinct immune escape mechanisms, highlighting specific immunotherapeutic targets and supporting application of this classification in future precision medicine trials.

CXCR4/CXCL12 blockade therapy; a new horizon in TNBC therapy

The only subtype of breast cancer (BC) without specific therapy is triple-negative breast cancer (TNBC), which represents 15-20% of incidence cases of BC. TNBC encompasses transformed and nonmalignant cells, including cancer-associated fibroblasts (CAF), endothelial vasculature, and tumor-infiltrating cells. These nonmalignant cells, soluble factors (e.g., cytokines), and the extracellular matrix (ECM) form the tumor microenvironment (TME). The TME is made up of these nonmalignant cells, ECM, and soluble components, including cytokines. Direct cell-to-cell contact and soluble substances like cytokines (e.g., chemokines) may facilitate interaction between cancer cells and the surrounding TME. Through growth-promoting cytokines, TME not only enables the development of cancer but also confers therapy resistance. New treatment targets will probably be suggested by comprehending the processes behind tumor development and progression as well as the functions of chemokines in TNBC. In this light, several investigations have shown the pivotal function of the C-X-C motif chemokine ligand 12 (CXCL12 or SDF-1) axis and chemokine receptor type 4 (CXCR4) in the pathophysiology of TNBC. This review provides an overview of the CXCR4/CXCL12 axis' function in TNBC development, metastasis, angiogenesis, and treatment resistance. A synopsis of current literature on targeting the CXCR4/CXCL12 axis for treating and managing TNBC has also been provided.

Chromosomal Instability and Clonal Heterogeneity in Breast Cancer: From Mechanisms to Clinical Applications

BACKGROUND

Chromosomal instability (CIN) and clonal heterogeneity (CH) are fundamental hallmarks of breast cancer that drive tumor evolution, disease progression, and therapeutic resistance. Understanding the mechanisms underlying these phenomena is essential for improving cancer diagnosis, prognosis, and treatment strategies.

METHODS

In this review, we provide a comprehensive overview of the biological processes contributing to CIN and CH, highlighting their molecular determinants and clinical relevance.

RESULTS

We discuss the latest advances in detection methods, including single-cell sequencing and other high-resolution techniques, which have enhanced our ability to characterize intratumoral heterogeneity. Additionally, we explore how CIN and CH influence treatment responses, their potential as therapeutic targets, and their role in shaping the tumor immune microenvironment, which has implications for immunotherapy effectiveness.

CONCLUSIONS

By integrating recent findings, this review underscores the impact of CIN and CH on breast cancer progression and their translational implications for precision medicine.

CBL0137 and NKG2A blockade: a novel immuno-oncology combination therapy for Myc-overexpressing triple-negative breast cancers

The MYC proto-oncogene is upregulated in >60% of triple-negative breast cancers (TNBCs), it can directly promote tumor cell proliferation, and its overexpression negatively regulates anti-tumor immune responses. For all these reasons, MYC has long been considered as a compelling therapeutic target. However, pharmacological inhibition of MYC function has proven difficult due to a lack of a drug-binding pocket. Here, we demonstrate that the potent abrogation of MYC gene transcription by CBL0137 induces immunogenic cell death and reduces proliferation in MYC-high but not in MYC-low TNBC in vitro. CBL0137 also significantly inhibited the in vivo growth of primary tumors in a human MYC-high TNBC xenograft model (MDA-MB-231). Moreover, CBL0137 inhibited the tumor growth of highly aggressive mouse 4T1.2 syngeneic TNBC model in immunocompetent mice by inhibiting the MYC pathway and inducing Type I interferon responses. Immune profiling of CBL0137-treated mice revealed significantly enhanced tumor-specific immune responses and increased proportions of tumor infiltrating effector CD8+ T cells, CD4+ T cells, and NK cells. CBL0137-induced immune activation also resulted in increased exhaustion of immune effector cells. In particular, NKG2A up-regulation on activated effector cells and of its ligand Qa-1b on tumors in vivo was identified as a possible immune evasive mechanism. Indeed, NKG2A blockade synergized with CBL0137 significantly inhibiting the in vivo growth of 4T1.2 tumors. Collectively, our findings provide the rationale supporting the exploitation of CBL0137-induced anti-tumor immunity in combination with NKG2A blockade to improve the treatment of TNBC expressing high levels of MYC.

Cyclin E1 overexpression triggers interferon signaling and is associated with antitumor immunity in breast cancer

BACKGROUND

Cyclin E1 overexpression drives oncogenesis in several cancers through deregulation of DNA replication and induction of genomic instability, which may potentially trigger immune signaling via cytoplasmic DNA. However, the effects of cyclin E1 overexpression on tumor immunity and its effects on the response to immune checkpoint inhibitors remain largely unclear.

METHODS

Tissue microarrays and clinical outcomes of 398 patients with breast cancer were analyzed to explore the correlation between cyclin E1 expression, patient survival, and immune cell infiltration using immunohistochemistry. Genomic data from publicly available data sets and three clinical trials evaluating immunotherapy were assessed to measure the impact of cyclin E1 expression on the immune cells in the tumor microenvironment and response to immunotherapy in patients with breast cancer. In addition, breast cancer cell lines with inducible cyclin E1 overexpression were employed to analyze the effects of cyclin E1 on inflammatory signaling.

RESULTS

Increased cyclin E1 expression in breast cancer was positively correlated with immune cell infiltration, including T cells, B cells, and natural killer cells, and activation of interferon-related pathways. Importantly, higher cyclin E1 expression or CCNE1 amplification was associated with better response to immunotherapy in three clinical trials. Mechanistically, cyclin E1 overexpression resulted in micronuclei formation and activation of innate immune signaling, resulting in increased immune cell migration.

CONCLUSIONS

Our data show that cyclin E1 overexpression associate with antitumor immunity through activation of innate inflammatory signaling and warrants investigation into amplification or overexpression of cyclin E1 in identifying patients with breast cancer eligible for immunotherapy.

Chemical evolution of ASO-like DNAzymes for effective and extended gene silencing in cells

Antisense oligonucleotides (ASOs) and small interfering RNA (siRNA) therapeutics highlight the power of oligonucleotides in silencing disease-causing messenger RNAs (mRNAs). Another promising class of gene-silencing oligonucleotides is RNA-cleaving nucleic acid enzymes, which offer the potential for allele-specific RNA inhibition with greater precision than ASOs and siRNAs. Herein, we chemically evolved the nucleolytic DNA enzyme (DNAzyme) 10-23, by incorporating the modifications that are essential to the success of ASO drugs, including 2'-fluoro, 2'-O-methyl, and 2'-O-methoxyethyl RNA analogues, and backbone phosphorothioate, to enhance catalytic efficiency by promoting RNA substrate binding and preventing dimerization of 10-23. These ASO-like DNAzymes cleaved structured RNA targets in long transcripts, showed prolonged intracellular stability, and downregulated mRNA and protein levels of both exogenously transfected eGFP and endogenously elevated oncogenic c-MYC. In colon cancer HCT116 cells, the downregulation of oncogenic c-MYC RNA resulted in cell cycle arrest, reduced proliferation, and increased apoptosis. RACE (rapid amplification of cDNA ends) polymerase chain reaction and Sanger sequencing confirmed precise, site-specific mRNA transcript cleavage with minimal RNase H activation in cells. By merging ASO structural and pharmacokinetic advantages with DNAzyme catalytic versatility, these ASO-like 10-23 variants offer a promising new class of potent gene-silencing agents, representing a significant step toward therapeutic DNAzyme development.

Defective X-chromosome inactivation and cancer risk in women

X-chromosome inactivation (XCI) is a fundamental mechanism in placental mammals that compensates for gene dosage differences between sexes. Using methylation levels of genes under XCI, we establish defective levels of XCI as a new source of interindividual variation among cancer types in females, characterized by a significant and consistent lowering of XIST expression and enrichment of differentially expressed genes under XCI. We show that defective XCI is an additive factor to the cancer risk of XCI escape deregulation in women. Defective XCI of more than 10% has an attributable risk of 40% among 12 different cancers from The Cancer Genome Atlas. Validations between independent studies of breast cancer samples show that defective XCI increases triple-negative subtype frequency, decreases survival rates, and is reduced by chemotherapy treatment. Mechanistically, it is associated with somatic mutations at TP53 and top MYC gains. In independent studies, defective XCI is detectable in blood and increases with aging, menopause, and cancer diagnosis.

Longitudinal multi-tracer imaging of hepatocellular carcinoma identifies novel stage- and oncogene-specific changes

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths, globally. There is a need for novel biomarkers for early detection and novel, effective targeted therapies. Molecular imaging can faithfully visualize, characterize and quantify specific relevant biological processes.

BASIC PROCEDURE

We performed longitudinal dedicated small-animal positron emission tomography-computed tomography (PET/CT) imaging to analyze changes in glucose metabolism using [18F]fluorodeoxyglucose ([18F]FDG), amino acid turnover with [18F]fluoroethyltyrosine ([18F]FET), and chemokine receptor expression using [68Ga]pentixafor targeting CXCR4, during stages of early tumor development, overt HCC and regression. We used two conditional transgenic mouse models of HCC, driven by clinically relevant oncogenes c-MYC (LT2/MYC) or HRASV12 (LT2/RAS). Conditional doxycycline-regulated mouse models, enable liver-specific oncogene activation or inhibition, leading to liver tumor development and regression, respectively. Correlation of our PET/CT findings with our gene expression and metabolomics data and with histological analyses followed.

MAIN FINDINGS

We show PET/CT identifies HCC stage-specific and oncogene-specific molecular changes that may serve as potential novel biomarkers and therapeutic targets. Glucose metabolism and CXCR4 chemokine expression are differentially deregulated during HCC development in an oncogene-specific manner. Our [18F]FDG results correlated with glucose transporter GLUT1 gene expression and with our metabolomics data. Increased expression of CXCR4 and CD68 inflammatory markers mirrored [68Ga]pentixafor results in LT2/MYC mice. FET-based measurement of amino acid turnover are insensitive to stages of HCC-development, in our studies. Concurrently, no significant changes in expression of tyrosine metabolism genes were observed.

PRINCIPAL CONCLUSIONS

Our study highlights that identified changes in targeted molecular imaging can facilitate a better understanding of underlying biological processes and may help guide novel oncogene-specific targeted anti-tumor therapies in HCC, with promising translational potential.

Biglycan fragment modulates TGF-β activity in intervertebral disc via an eIF6-coupled intracellular path

Biglycan, a pericellular small leucine-rich proteoglycan, is crucial in skeletal development and regeneration. Intervertebral disc degeneration (IDD) contributes to back pain and disability. Previous studies have shown that biglycan promotes hypoxic survival of disc progenitor cells, while its depletion accelerates IDD. An association of pathological tissue remodeling with a biglycan fragment 344YWEVQPATFR, termed Bgm1, has been reported, however its role is yet to be defined. Using a custom antibody, we detected Bgm1 in human and mouse nucleus pulposus, with prominent intracellular expression in notochordal cells. Proteomic analysis revealed that Bgm1 interacts with eukaryotic translation initiation factor 6 (eIF6), a key player in ribosome biogenesis. Bgm1 dysregulates eIF6 localization in notochordal cells, affecting nucleocytoplasmic transport. Induced IDD in mice showed elevated nuclear eIF6 expression and reduced Bgm1 in degenerating nucleus pulposus. Transcriptome analysis suggests that Bgm1 regulates fatty acid metabolism and glycolysis in a transforming growth factor-β-dependent manner, highlighting its potential role in metabolic control in spinal joint homeostasis.

Diffusion-based generation of gene regulatory networks from scRNA-seq data with DigNet

A gene regulatory network (GRN) intricately encodes the interconnectedness of identities and functionalities of genes within cells, ultimately shaping cellular specificity. Despite decades of endeavors, reverse engineering of GRNs from gene expression profiling data remains a profound challenge, particularly when it comes to reconstructing cell-specific GRNs that are tailored to precise cellular and genetic contexts. Here, we propose a discrete diffusion generation model, called DigNet, capable of generating corresponding GRNs from high-throughput single-cell RNA sequencing (scRNA-seq) data. DigNet embeds the network generation process into a multistep recovery procedure with Markov properties. Each intermediate step has a specific model to recover a portion of the gene regulatory architectures. It thus can ensure compatibility between global network structures and regulatory modules through the unique multistep diffusion procedure. Furthermore, through iMetacell integration and non-Euclidean discrete space modeling, DigNet is robust to the presence of noise in scRNA-seq data and the sparsity of GRNs. Benchmark evaluation results against more than a dozen state-of-the-art network inference methods demonstrate that DigNet achieves superior performance across various single-cell GRN reconstruction experiments. Furthermore, DigNet provides unique insights into the immune response in breast cancer, derived from differential gene regulation identified in T cells. As an open-source software, DigNet offers a powerful and effective tool for generating cell-specific GRNs from scRNA-seq data.

Immunotherapeutic effects of de novo benzimidazole derivative and prebiotic bacterial levan against triple-negative breast tumors by harnessing the immune landscape to intercept the oncogenic transcriptome

The current study aimed to investigate the therapeutic potential of a novel benzimidazole derivative (BMPE) and a prebiotic bacterial levan (LevAE) against triple-negative breast cancer (TNBC) in a 4T1-cell syngeneic mouse model and to elucidate the immunological and molecular mechanisms underlying the phenotypic changes observed in treated tumors. The metastatic TNBC model was successfully established by subcutaneous inoculation of 100 μL of 4T1 cell suspension (~6000 cells) in the mammary glands of adult female BALB/c mice after brief immunosuppression one day before cell implantation. The therapeutic efficacy of BMPE and LevAE was biochemically, immunologically, and immunohistochemically evaluated. Both compounds exhibited significant antitumor and antimetastatic effects through modulating the tumoral and systemic immune milieus and restoring the TME redox status, which ultimately suppressed the oncogenic transcriptome in the treated breast tumors. Compared to the reference drug (Doxorubicin), BMPE treatment resulted in nearly complete remission within 21 days of treatment, whereas LevAE was less convenient but produced a significant curative outcome. In light of these findings, BMPE and LevAE provide new paradigms for cancer immunotherapy.

Targeting MYC for the treatment of breast cancer: use of the novel MYC-GSPT1 degrader, GT19630

BACKGROUND

Since MYC is one of the most frequently altered driver genes involved in cancer formation, it is a potential target for new anti-cancer therapies. Historically, however, MYC has proved difficult to target due to the absence of a suitable crevice for binding potential low molecular weight drugs.

OBJECTIVE

The aim of this study was to evaluate a novel molecular glue, dubbed GT19630, which degrades both MYC and GSPT1, for the treatment of breast cancer.

METHODS

The antiproliferative potential of GT19630 was evaluated in 14 breast cancer cell lines representing the main molecular subtypes of breast cancer. In addition, we also investigated the effects of GT19630 on apoptosis, cell cycle progression, cell migration, and degradation of the negative immune checkpoint protein, B7-H3.

RESULTS

GT19630 inhibited cell proliferation, blocked cell cycle progression, promoted apoptosis, and decreased cell migration at low nanomolar concentrations in breast cancer cell lines. By contrast, previously described MYC inhibitors such as specific MYC-MAX antagonists affected these processes at micromolar concentrations. Consistent with the ability of MYC to promote immune evasion, we also found that GT19630 degraded the negative immune checkpoint inhibitor, B7-H3.

CONCLUSIONS

We conclude that the novel molecular glue, GT19630, is a potent mediator of endpoints associated with cancer formation/progression. Its ability to degrade B7-H3 suggests that GT19630 may also promote host immunity against cancer. To progress GT19630 as a therapy for breast cancer, our finding should now be confirmed in an animal model system.

BRCA1 and BRCA2: from cancer susceptibility to synthetic lethality

The discovery of BRCA1 and BRCA2 as tumor susceptibility genes and their role in genome maintenance has transformed our understanding of hereditary breast and ovarian cancer. This review traces the evolution of BRCA1/2 research over the past 30 years, highlighting key discoveries in the field and their contributions to tumor development. Additionally, we discuss current preventive measures for BRCA1/2 mutation carriers and targeted treatment options based on the concept of synthetic lethality. Finally, we explore the challenges of acquired therapy resistance and discuss potential alternative avenues for targeting BRCA1/2 mutant tumors.

Molecular heterogeneity and MYC dysregulation in triple-negative breast cancer: genomic advances and therapeutic implications

Triple-negative breast cancer (TNBC) is characterized by a diverse range of molecular features that have been extensively studied. MYC plays a critical role in regulating metabolism, differentiation, proliferation, cell growth, and apoptosis. Dysregulation of MYC is associated with poor prognosis and contributes to the development and progression of breast cancer. A particularly intriguing aspect of TNBC is its association with tumors in BRCA1 mutation carriers, especially in younger women. MYC may also contribute to resistance to adjuvant treatments. For TNBC, targeting MYC-regulated pathways in combination with inhibitors of other carcinogenic pathways offers a promising therapeutic approach. Several signaling pathways regulate TNBC, and targeting these pathways could lead to effective therapeutic strategies for breast cancer. Advances in genomic tools, such as CRISPR-Cas9, next-generation sequencing, and whole-exome sequencing, are revolutionizing breast cancer diagnoses. These technologies have significantly enhanced our understanding of MYC oncogenesis, particularly through CRISPR-Cas9 and NGS. Targeting MYC and its partner MAX could provide valuable insights into TNBC. Moreover, the therapeutic potential of targeting MYC-driven signaling mechanisms and their interactions with other oncogenic pathways, including PI3K/AKT/mTOR and Wnt/β-catenin, is increasingly recognized. Next-generation sequencing and CRISPR-Cas9 represent significant breakthroughs in genomic tools that open new opportunities to explore MYC's role in TNBC and facilitate the development of personalized treatment plans. This review discusses the future clinical applications of personalized treatment strategies for patients with TNBC.

Indirect targeting of MYC and direct targeting in combination with chemotherapies are more effective than direct mono-targeting in triple negative breast cancer

MYC amplification is disproportionally elevated in triple-negative breast cancer (TNBC) compared to other subtypes of breast cancer. Indeed, MYC has long been considered an undruggable oncogene using conventional drug design strategies or small molecules. We hypothesized that targeting MYC using asymmetric siRNA (asiRNA) alone or in combination with chemotherapeutic agents or indirectly via BRD4 and RRM2, may curb its oncogenic behavior. We developed paclitaxel-, doxorubicin-, and cisplatin-resistant MDA-MB-231 cells to study MYC's role in upregulating DNA repair genes during drug resistance development. Our results showed that the knockdown of either MYC or RRM2 downregulated both RAD51 and PARP1 but increased γH2AX. The cytotoxic effect of RRM2 knockdown was significantly (p < 0.05) higher than that of direct MYC knockdown. The knockdown of BRD4 was more effective than the direct knockdown of MYC in downregulating MYC protein. The combined use of asiRNA-VP (Vinylphosphonate) with dacomitinib or talazoparib was synthetic lethal in TNBC cell lines. Compared to chemotherapy-sensitive cells, resistant cells showed overexpression of MYC, RRM2, RAD51, and PARP1 proteins upon chemotherapy treatment, but downregulated in cells treated with asiRNA-VP combination. We confirmed that MYC knockdown upregulated cFLIP, BCL2, STAT1, pSTAT1, STAT2, and cleaved saspase-3 in both TNBC and non-small cell lung cancer (NSCLC) cell lines. Finally, we recommend a combination treatment approach that synergizes with MYC inhibition rather than monotherapy or indirect targeting via upstream regulators such as the BRD4 and RRM2 genes or selective modulation at the protein level to suppress anti-apoptotic genes (cFLIP and BCL2) at the same time.

SKP2 inhibition activates tumor cell-intrinsic immunity by inducing DNA replication stress and genomic instability

BACKGROUND

S-phase kinase-associated protein 2 (SKP2) is a typical oncogene aberrantly overexpressing in a variety of cancer types, but it remains elusive whether SKP2 regulates the antitumor immunity of triple-negative breast cancer.

METHODS

The efficacy of anti-PD-1 was evaluated in the orthotopic xenografts of immunocompetent mice models. The infiltration of cytotoxic T cells in tumor microenvironment(TME) were assessed by immunofluorescence staining. The levels of pro-inflammatory chemokines were analyzed by ELISA. The protein interaction was analyzed by co-immunoprecipitation and GST pull-down. The genomic instability was analyzed by fluorescent microscopy.

RESULTS

SKP2 inhibition significantly improved the antitumor efficacy of immune checkpoint blockade (ICB). Furthermore, SKP2 inhibition activated the cGAS/STING signal pathway and induced the secretion of pro-inflammatory chemokines, thereby promoting cytotoxic T cell infiltration. Additionally, we identified CDC6, a DNA replication licensing factor as a novel substrate of SKP2 in addition to CDT1. SKP2 induced protein degradation of CDC6 and CDT1 through the ubiquitin-proteasome pathway. Conversely, SKP2 inhibition elevated CDC6 and CDT1 protein levels, which caused DNA aberrant replication, DNA damage and genomic instability, thereby resulting in the accumulation of cytosolic DNA, activating cGAS/STING signaling pathway and improving antitumor immunity.

CONCLUSION

SKP2 may be used as an effective therapeutic target to enable ICB antitumor immunotherapy.

SOCIAL MEDIA

Peng et al. found that SKP2 inhibition improved the antitumor immunotherapy by activating tumor cell-intrinsic immunity, thereby providing evidences that SKP2 may be used as an effective therapeutic target to enable ICB antitumor immunotherapy.

The importance of type I interferon in orchestrating the cytotoxic T-cell response to cancer

Both type I interferon (IFN-I) and CD4+ T-cell help are required to generate effective CD8+ T-cell responses to cancer. We here outline based on existing literature how IFN-I signaling and CD4+ T-cell help are connected. Both impact on the functional state of dendritic cells (DCs), particularly conventional (c)DC1. The cDC1s are critical for crosspresentation of cell-associated antigens and for delivery of CD4+ T-cell help for cytotoxic T-lymphocyte (CTL) effector and memory differentiation. In infection, production of IFN-I is prompted by pathogen-associated molecular patterns (PAMPs), while in cancer it relies on danger-associated molecular patterns (DAMPs). IFN-I production by tumor cells and pDCs in the tumor micro-environment (TME) is often limited. IFN-I signals increase the ability of migratory cDC1s and cDC2s to transport tumor antigens to tumor-draining lymph nodes (tdLNs). IFN-I also enables cDC1s to form and sustain the platform for help delivery by stimulating the production of chemokines that attract CD4+ and CD8+ T cells. IFN-I promotes delivery of help in concert with CD40 signals by additive and synergistic impact on cross-presentation and provision of critical costimulatory and cytokine signals for CTL effector and memory differentiation. The scenario of CD4+ T-cell help therefore depends on IFN-I signaling. This scenario can play out in tdLNs as well as in the TME, thereby contributing to the cancer immunity cycle. The collective observations may explain why both IFN-I and CD4+ T-cell help signatures in the TME correlate with good prognosis and response to PD-1 targeting immunotherapy in human cancer. They also may explain why a variety of tumor types in which IFN-I signaling is attenuated, remain devoid of functional CTLs.

Delineating MYC-Mediated Escape Mechanisms from Conventional and T Cell-Redirecting Therapeutic Antibodies

In B-cell malignancies, the overexpression of MYC is associated with poor prognosis, but its mechanism underlying resistance to immunochemotherapy remains less clear. In further investigations of this issue, we show here that the pharmacological inhibition of MYC in various lymphoma and multiple myeloma cell lines, as well as patient-derived primary tumor cells, enhances their susceptibility to NK cell-mediated cytotoxicity induced by conventional antibodies targeting CD20 (rituximab) and CD38 (daratumumab), as well as T cell-mediated cytotoxicity induced by the CD19-targeting bispecific T-cell engager blinatumomab. This was associated with upregulation of the target antigen only for rituximab, suggesting additional escape mechanisms. To investigate these mechanisms, we targeted the MYC gene in OCI-LY18 cells using CRISPR-Cas9 gene-editing technology. CRISPR-Cas9-mediated MYC targeting not only upregulated CD20 but also triggered broader apoptotic pathways, upregulating pro-apoptotic PUMA and downregulating anti-apoptotic proteins BCL-2, XIAP, survivin and MCL-1, thereby rendering tumor cells more prone to apoptosis, a key tumor-lysis mechanism employed by T-cells and NK-cells. Moreover, MYC downregulation boosted T-cell activation and cytokine release in response to blinatumomab, revealing a MYC-mediated T-cell suppression mechanism. In conclusion, MYC overexpressing tumor cells mitigated the efficacy of therapeutic antibodies through several non-overlapping mechanisms. Given the challenges associated with direct MYC inhibition due to toxicity, successful modulation of MYC-mediated immune evasion mechanisms may improve the outcome of immunotherapeutic approaches in B-cell malignancies.

Evolving immunotherapeutic solutions for triple-negative breast carcinoma

Triple-negative breast carcinoma (TNBC) remains a formidable clinical hurdle owing to its high aggressiveness and scant therapeutic options. Nonetheless, the evolving landscape of immunotherapeutic strategies opens up promising avenues for tackling this hurdle. This review discusses the advancing immunotherapy for TNBC, accentuating personalized interventions due to tumor microenvironment (TME) diversity. Immune checkpoint inhibitors (ICIs) hold pivotal significance, both as single-agent therapies and when administered alongside cytotoxic agents. Moreover, the concurrent inhibition of multiple immune checkpoints represents a potent approach to augment the efficacy of cancer immunotherapy. Synergistic effects have been observed when ICIs are combined with targeted treatments like PARP inhibitors, anti-angiogenics, and ADCs (antibody-drug conjugates). Emerging tactics include tumor vaccines, cellular immunotherapy, and oncolytic viruses, leveraging the immune system's ability for selective malignant cell destruction. This review offers an in-depth examination of the diverse landscape of immunotherapy development for TNBC, furnishing meticulous insights into various advancements within this field. In addition, immunotherapeutic interventions offer hope for TNBC, needing further research for optimization.

Genomic instability as a driver and suppressor of anti-tumor immunity

Genomic instability is a driver and accelerator of tumorigenesis and influences disease outcomes across cancer types. Although genomic instability has been associated with immune evasion and worsened disease prognosis, emerging evidence shows that genomic instability instigates pro-inflammatory signaling and enhances the immunogenicity of tumor cells, making them more susceptible to immune recognition. While this paradoxical role of genomic instability in cancer is complex and likely context-dependent, understanding it is essential for improving the success rates of cancer immunotherapy. In this review, we provide an overview of the underlying mechanisms that link genomic instability to pro-inflammatory signaling and increased immune surveillance in the context of cancer, as well as discuss how genomically unstable tumors evade the immune system. A better understanding of the molecular crosstalk between genomic instability, inflammatory signaling, and immune surveillance could guide the exploitation of immunotherapeutic vulnerabilities in cancer.

Co-targeting CDK 4/6 and C-MYC/STAT3/CCND1 axis and inhibition of tumorigenesis and epithelial-mesenchymal-transition in triple negative breast cancer by Pt(II) complexes bearing NH3 as trans-co-ligand

In search of potential anticancer agents, we synthesized SNO-donor salicylaldimine main ligand-based Pt(II) complexes bearing NH3 as co-ligand at trans-position (C1-C6). These complexes showed similarity in structure with transplatin as the two N donor atoms of the main ligand and NH3 co-ligand were coordinated to Pt in trans position to each other. Each complex with different substituents on the main ligand was characterized thoroughly by detailed spectroscopic and spectrophotometric methods. Four of these complexes were studied in solid state by single crystal X-ray analysis. The stability of reference complex C1 was measured in solution state in DMSO‑d6 or its mixture with D2O using 1H NMR methods. These complexes were further investigated for their anticancer activity in triple-negative-breast (TNBC) cells including MDA-MB-231, MDA-MB-468 and MDA-MB-436 cells. All these complexes showed satisfactory cytotoxic effect as revealed by the MTT results. Importantly, the highly active complex C4 anticancer effect was compared to the standard chemotherapeutic agents including cisplatin, oxaliplatin and 5-fluorouracil (5-FU). Functionally, C4 suppressed invasion, spheroids formation ability and clonogenic potential of cancer cells. C4 showed synergistic anticancer effect when used in combination with palbociclib, JQ1 and paclitaxel in TNBC cells. Mechanistically, C4 inhibited cyclin-dependent kinase (CDK)4/6 pathway and targeted the expressions of MYC/STAT3/CCND1/CNNE1 axis. Furthermore, C4 suppressed the EMT signaling pathway that suggested a role of C4 in the inhibition of TNBC metastasis. Our findings may pave further in detailed mechanistic study on these complexes as potential chemotherapeutic agents in different types of human cancers.

Immune control in acute myeloid leukemia

Acute myeloid leukemia (AML) is a genetically heterogeneous disease, in that a multitude of oncogenic drivers and chromosomal abnormalities have been identified and associated with the leukemic transformation of myeloid blasts. However, little is known as to how individual mutations influence the interaction between the immune system and AML cells and the efficacy of the immune system in AML disease control. In this review, we will discuss how AML cells potentially activate the immune system and what evidence there is to support the role of the immune system in controlling this disease. We will specifically examine the importance of antigen presentation in fostering an effective anti-AML immune response, explore the disruption of immune responses during AML disease progression, and discuss the emerging role of the oncoprotein MYC in driving immune suppression in AML.

Immune evasion: An imperative and consequence of MYC deregulation

MYC has been implicated in the pathogenesis of a wide range of human tumors and has been described for many years as a transcription factor that regulates genes with pleiotropic functions to promote tumorigenic growth. However, despite extensive efforts to identify specific target genes of MYC that alone could be responsible for promoting tumorigenesis, the field is yet to reach a consensus whether this is the crucial function of MYC. Recent work shifts the view on MYC's function from being a gene-specific transcription factor to an essential stress resilience factor. In highly proliferating cells, MYC preserves cell integrity by promoting DNA repair at core promoters, protecting stalled replication forks, and/or preventing transcription-replication conflicts. Furthermore, an increasing body of evidence demonstrates that MYC not only promotes tumorigenesis by driving cell-autonomous growth, but also enables tumors to evade the host's immune system. In this review, we summarize our current understanding of how MYC impairs antitumor immunity and why this function is evolutionarily hard-wired to the biology of the MYC protein family. We show why the cell-autonomous and immune evasive functions of MYC are mutually dependent and discuss ways to target MYC proteins in cancer therapy.

Single-cell RNA-seq reveals heterogeneity in metastatic renal cell carcinoma and effect of anti-angiogenesis therapy in the pancreas metastatic lesion

Metastatic clear cell renal cell carcinoma has heterogenous tumor microenvironment (TME). Among the metastatic lesions, pancreas metastasis is rare and controversy in treatment approaches. Here, extensive primary and metastatic lesion samples were included by single-cell RNA-seq to decipher the distinct metastasis TME. The hypoxic and inflammatory TME of pancreas metastasis was decoded in this study, and the activation of PAX8-myc signaling, and metabolic reprogramming were observed. The active components including endothelial cells, fibroblasts and T cells were profiled. Meanwhile, we also evaluated the effect of anti-angiogenesis treatment in the pancreas metastasis patient. The potential mechanisms of pancreatic tropism, instability of genome, and the response of immunotherapy were also discussed in this work. Taken together, our findings suggest a clue to the heterogeneity in metastasis TME and provide evidence for the treatment of pancreas metastasis in renal cell carcinoma patients.

Leveraging single-cell transcriptomic data to uncover immune suppressive cancer cell subsets in triple-negative canine breast cancers

Introduction

Single-cell RNA sequencing (scRNA-seq) has become an essential tool for uncovering the complexities of various physiological and immunopathological conditions in veterinary medicine. However, there is currently limited information on immune-suppressive cancer subsets in canine breast cancers. In this study, we aimed to identify and characterize immune-suppressive subsets of triple-negative canine breast cancer (TNBC) by utilizing integrated scRNA-seq data from published datasets.

Methods

Published scRNA-seq datasets, including data from six groups of 30 dogs, were subjected to integrated bioinformatic analysis.

Results

Immune modulatory TNBC subsets were identified through functional enrichment analysis using immune-suppressive gene sets, including those associated with anti-inflammatory and M2-like macrophages. Key immune-suppressive signaling, such as viral infection, angiogenesis, and leukocyte chemotaxis, was found to play a role in enabling TNBC to evade immune surveillance. In addition, interactome analysis revealed significant interactions between distinct subsets of cancer cells and effector T cells, suggesting potential T-cell suppression.

Discussion

The present study demonstrates a versatile and scalable approach to integrating and analyzing scRNA-seq data, which successfully identified immune-modulatory subsets of canine TNBC. It also revealed potential mechanisms through which TNBC promotes immune evasion in dogs. These findings are crucial for advancing the understanding of the immune pathogenesis of canine TNBC and may aid in the development of new immune-based therapeutic strategies.

A Comprehensive Proteogenomic and Spatial Analysis of Innate and Acquired Resistance of Metastatic Melanoma to Immune Checkpoint Blockade Therapies

While a subset of patients with metastatic melanoma achieves durable responses to immune checkpoint blockade (ICB) therapies, the majority ultimately exhibit either innate or acquired resistance to these treatments. However, the molecular mechanisms underlying resistance to ICB therapies remain elusive and are warranted to elucidate. Here, we comprehensively investigated the tumor and tumor immune microenvironment (TIME) of paired pre- and post-treatment tumor specimens from metastatic melanoma patients who were primary or secondary resistance to anti-CTLA-4 and/or anti-PD-1/PD-L1 therapies. Differentially expressed gene (DEG) analysis and single-sample gene set enrichment analysis (ssGSEA) with transcriptomic data identified cell cycle and c-MYC signaling as pathway-based resistance signatures. And weighted gene co-expression network analysis (WGCNA) revealed the activation of a cross-resistance meta-program involving key signaling pathways related to tumor progression in ICB resistant melanoma. Moreover, spatially-resolved, image-based immune monitoring analysis by using NanoString's digital spatial profiling (DSP) and Cyclic Immunofluorescence (CyCIF) showed infiltration of suppressive immune cells in the tumor microenvironment of melanoma with resistance to ICB therapies. Our study reveals the molecular mechanisms underlying resistance to ICB therapies in patients with metastatic melanoma by conducting such integrated analyses of multi-dimensional data, and provides rationale for salvage therapies that will potentially overcome resistance to ICB therapies.

Statement of translational relevance

This study paves the way for the creation of innovative therapeutic strategies, aimed at subverting resistance to immune checkpoint blockade (ICB) therapies in metastatic melanoma patients. By unraveling the specific molecular mechanisms underlying resistance, scientists can design effective alternative treatments that target pathways such as pathways associated with cell cycle dysregulation and c-MYC signaling. Furthermore, through the application of advanced immune monitoring techniques such as NanoString Digital Spatial Profiling (DSP) and Cyclic Immunofluorescence (CyCIF), this study has significantly enriched our understanding of the tumor microenvironment. This enhanced characterization facilitates the discovery of potential biomarkers that may forecast a patient's response to ICB treatment. Ultimately, these advancements could potentially refine patient outcomes and foster the development of more personalized cancer treatments in the future.

Targeting chromosomal instability in patients with cancer

Chromosomal instability (CIN) is a hallmark of cancer and a driver of metastatic dissemination, therapeutic resistance, and immune evasion. CIN is present in 60-80% of human cancers and poses a formidable therapeutic challenge as evidenced by the lack of clinically approved drugs that directly target CIN. This limitation in part reflects a lack of well-defined druggable targets as well as a dearth of tractable biomarkers enabling direct assessment and quantification of CIN in patients with cancer. Over the past decade, however, our understanding of the cellular mechanisms and consequences of CIN has greatly expanded, revealing novel therapeutic strategies for the treatment of chromosomally unstable tumours as well as new methods of assessing the dynamic nature of chromosome segregation errors that define CIN. In this Review, we describe advances that have shaped our understanding of CIN from a translational perspective, highlighting both challenges and opportunities in the development of therapeutic interventions for patients with chromosomally unstable cancers.

CircCFL1 Promotes TNBC Stemness and Immunoescape via Deacetylation-Mediated c-Myc Deubiquitylation to Facilitate Mutant TP53 Transcription

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. TP53, which has a mutation rate of ≈70%-80% in TNBC patients, plays oncogenic roles when mutated. However, whether circRNAs can exert their effects on TNBC through regulating mutant TP53 has not been well evaluated. In this study, circCFL1, which is highly expressed in TNBC cells and tissues and has prognostic potential is identified. Functionally, circCFL1 promoted the proliferation, metastasis and stemness of TNBC cells. Mechanistically, circCFL1 acted as a scaffold to enhance the interaction between HDAC1 and c-Myc, further promoting the stability of c-Myc via deacetylation-mediated inhibition of K48-linked ubiquitylation. Stably expressed c-Myc further enhanced the expression of mutp53 in TNBC cells with TP53 mutations by directly binding to the promoter of TP53, which promoted the stemness of TNBC cells via activation of the p-AKT/WIP/YAP/TAZ pathway. Moreover, circCFL1 can facilitate the immune escape of TNBC cells by promoting the expression of PD-L1 and suppressing the antitumor immunity of CD8+ T cells. In conclusion, the results revealed that circCFL1 plays an oncogenic role by promoting the HDAC1/c-Myc/mutp53 axis, which can serve as a potential diagnostic biomarker and therapeutic target for TNBC patients with TP53 mutations.

Convergent alterations in the tumor microenvironment of MYC-driven human and murine prostate cancer

How prostate cancer cells and their precursors mediate changes in the tumor microenvironment (TME) to drive prostate cancer progression is unclear, in part due to the inability to longitudinally study the disease evolution in human tissues. To overcome this limitation, we perform extensive single-cell RNA-sequencing (scRNA-seq) and molecular pathology of the comparative biology between human prostate cancer and key stages in the disease evolution of a genetically engineered mouse model (GEMM) of prostate cancer. Our studies of human tissues reveal that cancer cell-intrinsic activation of MYC signaling is a common denominator across the well-known molecular and pathological heterogeneity of human prostate cancer. Cell communication network and pathway analyses in GEMMs show that MYC oncogene-expressing neoplastic cells, directly and indirectly, reprogram the TME during carcinogenesis, leading to a convergence of cell state alterations in neighboring epithelial, immune, and fibroblast cell types that parallel key findings in human prostate cancer.

Phosphorylation of USP27X by PIM2 promotes glycolysis and breast cancer progression via deubiquitylation of MYC

Aberrant cell proliferation is a hallmark of cancer, including breast cancer. Here, we show that USP27X is required for cell proliferation and tumorigenesis in breast cancer. We identify a PIM2-USP27X regulator of MYC signaling axis whose activity is an important contributor to the tumor biology of breast cancer. PIM2 phosphorylates USP27X, and promotes its deubiquitylation activity for MYC, which promotes its protein stability and leads to increase HK2-mediated aerobic glycolysis in breast cancer. Moreover, the PIM2-USP27X-MYC axis is also validated in PIM2-knockout mice. Taken together, these findings show a PIM2-USP27X-MYC signaling axis as a new potential target for breast cancer treatment.

Disrupting prostate cancer research: Challenge accepted; report from the 2023 Coffey-Holden Prostate Cancer Academy Meeting

INTRODUCTION

The 2023 Coffey-Holden Prostate Cancer Academy (CHPCA) Meeting, themed "Disrupting Prostate Cancer Research: Challenge Accepted," was convened at the University of California, Los Angeles, Luskin Conference Center, in Los Angeles, CA, from June 22 to 25, 2023.

METHODS

The 2023 marked the 10th Annual CHPCA Meeting, a discussion-oriented scientific think-tank conference convened annually by the Prostate Cancer Foundation, which centers on innovative and emerging research topics deemed pivotal for advancing critical unmet needs in prostate cancer research and clinical care. The 2023 CHPCA Meeting was attended by 81 academic investigators and included 40 talks across 8 sessions.

RESULTS

The central topic areas covered at the meeting included: targeting transcription factor neo-enhancesomes in cancer, AR as a pro-differentiation and oncogenic transcription factor, why few are cured with androgen deprivation therapy and how to change dogma to cure metastatic prostate cancer without castration, reducing prostate cancer morbidity and mortality with genetics, opportunities for radiation to enhance therapeutic benefit in oligometastatic prostate cancer, novel immunotherapeutic approaches, and the new era of artificial intelligence-driven precision medicine.

DISCUSSION

This article provides an overview of the scientific presentations delivered at the 2023 CHPCA Meeting, such that this knowledge can help in facilitating the advancement of prostate cancer research worldwide.

The Engineered Drug 3'UTRMYC1-18 Degrades the c-MYC-STAT5A/B-PD-L1 Complex In Vivo to Inhibit Metastatic Triple-Negative Breast Cancer

c-MYC is overexpressed in 70% of human cancers, including triple-negative breast cancer (TNBC), yet there is no clinically approved drug that directly targets it. Here, we engineered the mRNA-stabilizing poly U sequences within the 3'UTR of c-MYC to specifically destabilize and promote the degradation of c-MYC transcripts. Interestingly, the engineered derivative outcompetes the endogenous overexpressed c-MYC mRNA, leading to reduced c-MYC mRNA and protein levels. The iron oxide nanocages (IO-nanocages) complexed with MYC-destabilizing constructs inhibited primary and metastatic tumors in mice bearing TNBC and significantly prolonged survival by degrading the c-MYC-STAT5A/B-PD-L1 complexes that drive c-MYC-positive TNBC. Taken together, we have described a novel therapy for c-MYC-driven TNBC and uncovered c-MYC-STAT5A/B-PD-L1 interaction as the target.

MYC and p53 alterations cooperate through VEGF signaling to repress cytotoxic T cell and immunotherapy responses in prostate cancer

Patients with castration-resistant prostate cancer (CRPC) are generally unresponsive to tumor targeted and immunotherapies. Whether genetic alterations acquired during the evolution of CRPC impact immune and immunotherapy responses is largely unknown. Using our innovative electroporation-based mouse models, we generated distinct genetic subtypes of CRPC found in patients and uncovered unique immune microenvironments. Specifically, mouse and human prostate tumors with MYC amplification and p53 disruption had weak cytotoxic lymphocyte infiltration and an overall dismal prognosis. MYC and p53 cooperated to induce tumor intrinsic secretion of VEGF, which by signaling through VEGFR2 expressed on CD8+ T cells, could directly inhibit T cell activity. Targeting VEGF-VEGFR2 signaling in vivo led to CD8+ T cell-mediated tumor and metastasis growth suppression and significantly increased overall survival in MYC and p53 altered CPRC. VEGFR2 blockade also led to induction of PD-L1, and in combination with PD-L1 immune checkpoint blockade produced anti-tumor efficacy in multiple preclinical CRPC mouse models. Thus, our results identify a genetic mechanism of immune suppression through VEGF signaling in prostate cancer that can be targeted to reactivate immune and immunotherapy responses in an aggressive subtype of CRPC.

Significance

Though immune checkpoint blockade (ICB) therapies can achieve curative responses in many treatment-refractory cancers, they have limited efficacy in CRPC. Here we identify a genetic mechanism by which VEGF contributes to T cell suppression, and demonstrate that VEGFR2 blockade can potentiate the effects of PD-L1 ICB to immunologically treat CRPC.

Suppression of interferon α and γ response by Huwe1-mediated Miz1 degradation promotes SARS-CoV-2 replication

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been demonstrated to limit the host interferon response; however, the underlying mechanism remains unclear. Here, we found that SARS-CoV-2 infection upregulated the E3 ubiquitin ligase Huwe1, which in turn facilitated the degradation of the transcription factor Miz1. The degradation of Miz1 hampered interferon alpha and gamma responses, consequently fostering viral replication and impeding viral clearance. Conversely, silencing or inhibiting Huwe1 enhanced the interferon responses, effectively curbing viral replication. Consistently, overexpressing Miz1 augmented the interferon responses and limited viral replication, whereas silencing Miz1 had the opposite effect. Targeting Huwe1 or overexpressing Miz1 elicited transcriptomic alterations characterized by enriched functions associated with bolstered antiviral response and diminished virus replication. Further study revealed Miz1 exerted epigenetic control over the transcription of specific interferon signaling molecules, which acted as common upstream regulators responsible for the observed transcriptomic changes following Huwe1 or Miz1 targeting. These findings underscore the critical role of the Huwe1-Miz1 axis in governing the host antiviral response, with its dysregulation contributing to the impaired interferon response observed during COVID-19.

Engineered Immunologic Niche Monitors Checkpoint Blockade Response and Probes Mechanisms of Resistance

Antibodies to programmed cell death protein1 (anti-PD-1) have become a promising immunotherapy for triple negative breast cancer (TNBC), blocking PD-L1 signaling from pro-tumor cells through T cell PD-1 receptor binding. Nevertheless, only 10-20% of PD-L1+ metastatic TNBC patients who meet criteria benefit from ICB, and biomarkers to predict patient response have been elusive. We have previously developed an immunological niche, consisting of a microporous implant in the subcutaneous space, that supports tissue formation whose immune composition is consistent with that within vital organs. Herein, we investigated dynamic gene expression within this immunological niche to provide biomarkers of response to anti-PD-1. In a 4T1 model of metastatic TNBC, we observed sensitivity and resistance to anti-PD-1 based on primary tumor growth and survival. The niche was biopsied before, during, and after anti-PD-1 therapy, and analyzed for cell types and gene expression indicative of treatment refractivity. Myeloid cell-to-lymphocyte ratios were altered between ICB-sensitivity and resistance. Longitudinal analysis of gene expression implicated dynamic myeloid cell function that stratified sensitivity from resistance. A niche-derived gene signature predicted sensitivity or resistance prior to therapy. Analysis of the niche to monitor immunotherapy response presents a new opportunity to personalize care and investigate mechanisms underlying treatment resistance.

METTL3 orchestrates glycolysis by stabilizing the c-Myc/WDR5 complex in triple-negative breast cancer

BACKGROUND

The carcinogenic transcription factor c-Myc is the most aggressive oncogene, which drive malignant transformation and dissemination of triple-negative breast cancer (TNBC). Recruitment of many cofactors, especially WDR5, a protein that nucleates H3K4me chromatin modifying complexes, play a pivotal role in regulating c-Myc-dependent gene transcription, a critical process for c-Myc signaling to function in a variety of biological and pathological contexts. For this reason, interrupting the interaction between c-Myc and the transcription cofactor WDR5 may become the most promising new strategy for treating c-Myc driven TNBC.

METHODS

Immunoprecipitation and mass spectrometry (IP-MS) is used to screen proteins that bind c-Myc/WDR5 interactions. The interaction of METTL3 with c-Myc/WDR5 in breast cancer tissues and TNBC cells was detected by Co-IP and immunofluorescence. Subsequently, we further analyzed the influence of METTL3 expression on c-Myc/WDR5 protein expression and its interaction stability by Western blot and Co-IP. The correlation between METTL3 and c-Myc pathway was analyzed by ChIP-seq sequencing and METTL3 knockdown transcriptome data. The effect of METTL3 expression on c-Myc transcriptional activity was detected by ChIP-qPCR and Dual Luciferase Reporter. At the same time, the overexpression vector METTL3-MUT (m6A) was constructed, which mutated the methyltransferase active site (Aa395-398, DPPW/APPA), and further explored whether the interaction between METTL3 and c-Myc/WDR5 was independent of methyltransferase activity. In addition, we also detected the changes of METTL3 expression on TNBC's sensitivity to small molecule inhibitors such as JQ1 and OICR9429 by CCK8, Transwell and clonal formation assays. Finally, we further verified our conclusions in spontaneous tumor formation mouse MMTV-PyMT and nude mouse orthotopic transplantation tumor models.

RESULTS

METTL3 was found to bind mainly to c-Myc/WDR5 protein in the nucleus. It enhances the stability of c-Myc/WDR5 interaction through its methyltransferase independent mechanism, thereby enhancing the transcriptional activity of c-Myc on downstream glucose metabolism genes. Notably, the study also confirmed that METTL3 can directly participate in the transcription of glucose metabolism genes as a transcription factor, and knockdown METTL3 enhances the drug sensitivity of breast cancer cells to small molecule inhibitors JQ1 and OICR9429. The study was further confirmed by spontaneous tumor formation mouse MMTV-PyMT and nude mouse orthotopic transplantation tumor models.

CONCLUSION

METTL3 binds to the c-Myc/WDR5 protein complex and promotes glycolysis, which plays a powerful role in promoting TNBC progression. Our findings further broaden our understanding of the role and mechanism of action of METTL3, and may open up new therapeutic avenues for effective treatment of TNBC with high c-Myc expression.

N-MYC impairs innate immune signaling in high-grade serous ovarian carcinoma

High-grade serous ovarian cancer (HGSC) is a challenging disease, especially for patients with immunologically "cold" tumors devoid of tumor-infiltrating lymphocytes (TILs). We found that HGSC exhibits among the highest levels of MYCN expression and transcriptional signature across human cancers, which is strongly linked to diminished features of antitumor immunity. N-MYC repressed basal and induced IFN type I signaling in HGSC cell lines, leading to decreased chemokine expression and T cell chemoattraction. N-MYC inhibited the induction of IFN type I by suppressing tumor cell-intrinsic STING signaling via reduced STING oligomerization, and by blunting RIG-I-like receptor signaling through inhibition of MAVS aggregation and localization in the mitochondria. Single-cell RNA sequencing of human clinical HGSC samples revealed a strong negative association between cancer cell-intrinsic MYCN transcriptional program and type I IFN signaling. Thus, N-MYC inhibits tumor cell-intrinsic innate immune signaling in HGSC, making it a compelling target for immunotherapy of cold tumors.

Dual-Epigenetically Relieving the MYC-Correlated Immunosuppression via an Advanced Nano-Radiosensitizer Potentiates Cancer Immuno-Radiotherapy

Cancer cells can upregulate the MYC expression to repair the radiotherapy-triggered DNA damage, aggravating therapeutic resistance and tumor immunosuppression. Epigenetic treatment targeting the MYC-transcriptional abnormality may intensively solve this clinical problem. Herein, 5-Aza (a DNA methyltransferase inhibitor) and ITF-2357 (a histone deacetylase inhibitor) are engineered into a tungsten-based nano-radiosensitizer (PWAI), to suppress MYC rising and awaken robust radiotherapeutic antitumor immunity. Individual 5-Aza depletes MYC expression but cannot efficiently awaken radiotherapeutic immunity. This drawback can be overcome by the addition of ITF-2357, which triggers cancer cellular type I interferon (IFN-I) signaling. Coupling 5-Aza with ITF-2357 ensures that PWAI does not evoke the treated model with high MYC-related immune resistance while amplifying the radiotherapeutic tumor killing, and more importantly promotes the generation of IFN-I signal-related proteins involving IFN-α and IFN-β. Unlike the radiation treatment alone, PWAI-triggered immuno-radiotherapy remarkably enhances antitumor immune responses involving the tumor antigen presentation by dendritic cells, and improves intratumoral recruitment of cytotoxic T lymphocytes and their memory-phenotype formation in 4T1 tumor-bearing mice. Downgrading the radiotherapy-induced MYC overexpression via the dual-epigenetic reprogramming strategy may elicit a robust immuno-radiotherapy.

Residual OXPHOS is required to drive primary and metastatic lung tumours in an orthotopic breast cancer model

Background

Fast adaptation of glycolytic and mitochondrial energy pathways to changes in the tumour microenvironment is a hallmark of cancer. Purely glycolytic ρ0 tumour cells do not form primary tumours unless they acquire healthy mitochondria from their micro-environment. Here we explored the effects of severely compromised respiration on the metastatic capability of 4T1 mouse breast cancer cells.

Methods

4T1 cell lines with different levels of respiratory capacity were generated; the Seahorse extracellular flux analyser was used to evaluate oxygen consumption rates, fluorescent confocal microscopy to assess the number of SYBR gold-stained mitochondrial DNA nucleoids, and the presence of the ATP5B protein in the cytoplasm and fluorescent in situ nuclear hybridization was used to establish ploidy. MinION nanopore RNA sequence analysis was used to compare mitochondrial DNA transcription between cell lines. Orthotopic injection was used to determine the ability of cells to metastasize to the lungs of female Balb/c mice.

Results

OXPHOS-deficient ATP5B-KO3.1 cells did not generate primary tumours. Severely OXPHOS compromised ρ0D5 cells generated both primary tumours and lung metastases. Cells generated from lung metastasis of both OXPHOS-competent and OXPHOS-compromised cells formed primary tumours but no metastases when re-injected into mice. OXPHOS-compromised cells significantly increased their mtDNA content, but this did not result in increased OXPHOS capacity, which was not due to decreased mtDNA transcription. Gene set enrichment analysis suggests that certain cells derived from lung metastases downregulate their epithelial-to-mesenchymal related pathways.

Conclusion

In summary, OXPHOS is required for tumorigenesis in this orthotopic mouse breast cancer model but even very low levels of OXPHOS are sufficient to generate both primary tumours and lung metastases.

The interplay between autophagy and cGAS-STING signaling and its implications for cancer

Autophagy is an intracellular process that targets various cargos for degradation, including members of the cGAS-STING signaling cascade. cGAS-STING senses cytosolic double-stranded DNA and triggers an innate immune response through type I interferons. Emerging evidence suggests that autophagy plays a crucial role in regulating and fine-tuning cGAS-STING signaling. Reciprocally, cGAS-STING pathway members can actively induce canonical as well as various non-canonical forms of autophagy, establishing a regulatory network of feedback mechanisms that alter both the cGAS-STING and the autophagic pathway. The crosstalk between autophagy and the cGAS-STING pathway impacts a wide variety of cellular processes such as protection against pathogenic infections as well as signaling in neurodegenerative disease, autoinflammatory disease and cancer. Here we provide a comprehensive overview of the mechanisms involved in autophagy and cGAS-STING signaling, with a specific focus on the interactions between the two pathways and their importance for cancer.

Genetic mechanisms underlying tumor microenvironment composition and function in diffuse large B-cell lymphoma

ABSTRACT

Cells in the tumor microenvironment (TME) of diffuse large B-cell lymphoma (DLBCL) show enormous diversity and plasticity, with functions that can range from tumor inhibitory to tumor supportive. The patient's age, immune status, and DLBCL treatments are factors that contribute to the shaping of this TME, but evidence suggests that genetic factors, arising principally in lymphoma cells themselves, are among the most important. Here, we review the current understanding of the role of these genetic drivers of DLBCL in establishing and modulating the lymphoma microenvironment. A better comprehension of the relationship between lymphoma genetic factors and TME biology should lead to better therapeutic interventions, especially immunotherapies.