ATM Inhibition-Induced ISG15/IFI27/OASL Is Correlated with Immunotherapy Response and Inflamed Immunophenotype

Identification of IFI27 involvement in the progression of neuroblastoma through bioinformatics analysis and experimental assays

Neuroblastoma (NB) is a prevalent extracranial malignant neuroendocrine tumor in children, originating from the sympathetic nervous system. This study aims to investigate new therapeutic targets for NB. The differentially expressed genes were screened by analyzing the GSE35133 and GSE90689 datasets. Hub genes were identified by constructing a protein-protein interaction network. The diagnostic value of the hub genes was assessed through the analysis of receiver operating characteristic (ROC) curves and the expression, prognosis, and immune infiltration of IFI27 in pan-cancer were analyzed on the online website Sangerbox. The hub gene expression levels were validated by performing real-time reverse transcriptase-polymerase chain reaction. The functions of IFI27 in NB were investigated by Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine, wound healing, and Transwell assays. Six candidate genes (IFI27, TNFSF10, IFI44, DDX58, HIST1H1C, and HIST1H1E) were identified as potential diagnostic biomarkers for NB. The expression levels of IFI27, TNFSF10, IFI44, and DDX58 were significantly decreased, while HIST1H1C and HIST1H1E were elevated. Notably, IFI27 displayed correlations with prognosis and immune infiltration in multiple tumors. In vitro, functional assays demonstrated that the knockdown of IFI27 promoted the proliferation, migration, and invasion of U251 cells. Conversely, in SK-N-AS cells, IFI27 overexpression inhibited cell proliferation, migration, and invasion. IFI27 was lowly expressed in NB and participated in the progression of NB, which provides a new insight into the pathogenic mechanism and novel therapeutic strategy for NB.

IFI27 enhances bladder cancer immunotherapy response by modulating regulatory T cell enrichment

Bladder cancer (BCa) is the 10th most prevalent cancer globally. Neoadjuvant therapy has become the standard treatment for muscle-invasive bladder cancer, yet the pathologic complete response rate for patients is only approximately 35%. However, the mechanisms underlying neoadjuvant therapy resistance in bladder cancer patients remain unclear. We collected two sets of paired bladder cancer specimens before and after neoadjuvant therapy, and performed RNA sequencing. The findings revealed a significant decrease in IFI27 expression levels in the post-neoadjuvant therapy group compared to samples collected before treatment, suggesting that IFI27 may play a role in resistance to neoadjuvant combination therapy. IFI27, a member of the interferon-alpha (IFN-α) inducible gene family, influences the efficacy of immune checkpoint blockade therapy. Further analysis demonstrated that IFI27 is predominantly expressed in the cytoplasm of bladder cancer cells and exhibited low expression levels in bladder cancer tissues and cell lines. Subsequently, we investigated the inhibitory effects of IFI27 on bladder cancer proliferation, migration, epithelial-mesenchymal transition, and lymph node metastasis. Additionally, in a mouse model, PD-1Ab immunotherapy was found to upregulate IFI27 while downregulating the protein level of FOXP3, a key transcription factor for regulatory T cells. Flow cytometric analysis further demonstrated that IFI27 inhibits bladder cancer progression by suppressing regulatory T cell infiltration and enhancing anti-tumor immune responses. In conclusion, these findings establish IFI27 as a promising molecular marker for improving the efficacy of immunotherapy in bladder cancer and offer valuable insights into strategies for enhancing immunotherapy sensitivity.

ATM inhibition enhance immunotherapy by activating STING signaling and augmenting MHC Class I

Accumulating evidence supports the concept that DNA damage response targeted therapies can improve antitumor immune response by increasing the immunogenicity of tumor cells and improving the tumor immune microenvironment. Ataxia telangiectasia mutated (ATM) is a core component of the DNA repair system. Although the ATM gene has a significant mutation rate in many human cancers, including colorectal, prostate, lung, and breast, it remains understudied compared with other DDR-involved molecules such as PARP and ATR. Here, we found that either gene knockout or drug intervention, ATM inhibition activated the cGAS/STING pathway and augmented MHC class I in CRC cells, and these effects could be amplified by radiation. Furthermore, we found that MHC class I upregulation induced by ATM inhibition is dependent on the activation of the NFκB/IRF1/NLRC5 pathway and independent of STING. Animal experiments have shown increasing infiltration and cytotoxic function of T cells and better survival in ATM-deficient tumors. This work indicated that ATM nonsense mutation predicted the clinical benefits of radiotherapy combined with immune checkpoint blockade for patients with CRC. It also provides a molecular mechanism rationale for ATM-targeted agents for patients with CRC.

Protumorigenic Interferon-Stimulated Genes in Cancer: A Comprehensive Review

Interferon-stimulated genes (ISGs), whose production is triggered by interferons, are known to defend the host from pathogenic and cancer-specific antigens, one of which is by inducing apoptosis in infected or mutated cells. It has been reported recently that specific ISGs aid cancer cells in evading immunosurveillance and inflammatory cells by inhibiting the apoptosis process. This report reviewed four apoptosis-regulating ISG proteins: interferon-stimulated gene 15 (ISG15), interferon alpha-inducible protein 27 (IFI27), interferon alpha-inducible protein 6 (IFI6), and radical S-adenosyl methionine domain containing 2 (RSAD2), demonstrating anti-apoptosis function, and considered them protumorigenic.

DNA-PK and ATM drive phosphorylation signatures that antagonistically regulate cytokine responses to herpesvirus infection or DNA damage

The DNA-dependent protein kinase, DNA-PK, is an essential regulator of DNA damage repair. DNA-PK-driven phosphorylation events and the activated DNA damage response (DDR) pathways are also components of antiviral intrinsic and innate immune responses. Yet, it is not clear whether and how the DNA-PK response differs between these two forms of nucleic acid stress-DNA damage and DNA virus infection. Here, we define DNA-PK substrates and the signature cellular phosphoproteome response to DNA damage or infection with the nuclear-replicating DNA herpesvirus, HSV-1. We establish that DNA-PK negatively regulates the ataxia-telangiectasia-mutated (ATM) DDR kinase during viral infection. In turn, ATM blocks the binding of DNA-PK and the nuclear DNA sensor IFI16 to viral DNA, thereby inhibiting cytokine responses. However, following DNA damage, DNA-PK enhances ATM activity, which is required for IFN-β expression. These findings demonstrate that the DDR autoregulates cytokine expression through the opposing modulation of DDR kinases.

Multiplexed high-throughput immune cell imaging in patients with high-risk triple negative early breast cancer: Analysis from the International Breast Cancer Study Group (IBCSG) Trial 22-00

BACKGROUND

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer (BC) subtype, with dismal prognosis and limited option in advanced settings, yet stromal tumor infiltrating lymphocytes (sTILs) in this subtype has a predictive role.

PATIENTS AND METHODS

The International Breast Cancer Study Group (IBCSG) Trial 22-00 is a randomized phase III clinical trial testing the efficacy of low-dose metronomic oral Cyclophosphamide-Methotrexate (CM) maintenance following standard adjuvant chemotherapy treatment for early-stage hormone receptor-negative breast cancer patients. A case-cohort sampling was used. We characterized immune cells infiltrates in patients with TNBC by 6 plex immunofluorescence (IF) staining for CD4, FOXP3, CD3, cytokeratine and CD8 RESULTS: We confirmed that high immune CD3+ T cells as well as stromal and intra-epithelial Tregs (CD4+Foxp3+ T cells) infiltrates were associated with a better Distant Recurrence-Free Interval (DRFI), especially in LN+ patient, regardless of the treatment. More importantly, we showed that the spatial distribution of immune cells at baseline is crucial, as CM maintenance was detrimental for T cells excluded LN+ TNBC patients.

CONCLUSIONS

immune spatial classification on immune cells infiltrates seems crucial and could help patients' selection in clinical trial and greatly improve responses to specific therapies.

Targeting mitotic regulators in cancer as a strategy to enhance immune recognition

Eukaryotic DNA has evolved to be enclosed within the nucleus to protect the cellular genome from autoinflammatory responses driven by the immunogenic nature of cytoplasmic DNA. Cyclic GMP-AMP Synthase (cGAS) is the cytoplasmic dsDNA sensor, which upon activation of Stimulator of Interferon Genes (STING), mediates production of pro-inflammatory interferons (IFNs) and interferon stimulated genes (ISGs). However, although this pathway is crucial in detection of viral and microbial genetic material, cytoplasmic DNA is not always of foreign origin. It is now recognised that specifically in genomic instability, a hallmark of cancer, extranuclear material in the form of micronuclei (MN) can be generated as a result of unresolved DNA lesions during mitosis. Activation of cGAS-STING in cancer has been shown to regulate numerous tumour-immune interactions such as acquisition of 'immunologically hot' phenotype which stimulates immune-mediated elimination of transformed cells. Nonetheless, a significant percentage of poorly prognostic cancers is 'immunologically cold'. As this state has been linked with low proportion of tumour-infiltrating lymphocytes (TILs), improving immunogenicity of cold tumours could be clinically relevant by exhibiting synergy with immunotherapy. This review aims to present how inhibition of vital mitotic regulators could provoke cGAS-STING response in cancer and improve the efficacy of current immunotherapy regimens.