Mengdi He

Mannose Enhances Immunotherapy Efficacy in Ovarian Cancer by Modulating Gut Microbial Metabolites

Abstract The gut microbiome significantly influences the effectiveness of immune checkpoint blockade therapy. However, its clinical application is hindered by the absence of cost-effective production methods. In this study, we demonstrated that oral mannose supplementation inhibits ovarian tumor growth in immunocompetent mice through the enrichment of Faecalibaculum rodentium (F. rodentium). Administration of F. rodentium not only suppressed tumor progression but also enhanced antitumor immune responses. Mannose supplementation fostered an immune stimulatory tumor microenvironment, characterized by the expansion and differentiation of progenitor-exhausted CD8+ T cells (Tpex). Metabolomics analysis identified propionate and butyrate as critical metabolites driving the mannose-mediated tumor-suppressive effects, which was validated in vivo. Mechanistically, propionate and butyrate enhanced histone acetylation to promote Tpex-cell expansion. Moreover, a mannose-related gene signature was associated with favorable response to immune checkpoint blockade therapy across multiple cancer types. Supplementation with mannose also improved the efficacy of anti–PD-1 therapy and PARP inhibitor treatment. These findings highlight the role of F. rodentium–derived metabolites propionate and butyrate as key stimulators of Tpex-cell expansion, thereby activating antitumor immune responses. This underscores the therapeutic potential of mannose supplementation in enhancing cancer immunotherapy outcomes in high-grade serous ovarian cancer. Significance: Alterations to the gut microbiome induced by mannose engender an immune stimulatory tumor microenvironment responsive to immunotherapy, suggesting that mannose may be an effective and safe adjuvant therapy for stimulating immunotherapy sensitivity.

Attenuation of Sialylation Augments Antitumor Immunity and Improves Response to Immunotherapy in Ovarian Cancer

Abstract Aberrant sialylation functions as an important modulator of all steps of malignant transformation. Therefore, targeting sialylation regulators, such as sialyltransferases and neuraminidases, is a potential strategy for treating cancer. Here, we found that elevated α2,3-sialyltransferase III (St3gal3) was associated with dismal prognosis in high-grade serous ovarian carcinoma (HGSC). St3gal3 knockdown antagonized subcutaneous tumor growth in immunocompetent, but not immunodeficient mice, with enhanced accumulation of functional CD8+ T cells and antitumor immune gene signatures. St3gal3 knockdown inhibited intraperitoneal tumor growth and repolarized tumor-associated macrophages from a protumorigenic M2-like to a tumor-suppressive M1-like phenotype. In vitro, St3gal3 knockdown tumor cells guided bone marrow–derived macrophages (BMDM) toward the M1-like phenotype under both direct contact and distant Transwell coculture conditions. Depletion of macrophages rescued the suppressed tumor growth induced by St3gal3 knockdown and completely suppressed infiltration of functional CD8+ T cells that rely on macrophage-derived CXCL10. St3gal3 engendered an immunosuppressive HGSC microenvironment characterized by an abundance of pro-tumorigenic macrophages and reduced cytotoxic T-cell infiltration. In vivo, St3gal3 knockdown improved effectiveness of dual immune checkpoint blockade (ICB) with αPD-1 and αCTLA4 antibodies. Preclinical inhibition of sialylation with ambroxol resulted in decreased tumor growth and prolonged the survival of tumor-bearing mice, which was enhanced by the addition of dual ICB. These findings indicate that altered sialylation induced by St3gal3 upregulation promotes a tumor-suppressive microenvironment in HGSC and targeting α2,3-sialylation may reprogram the immunosuppressive tumor microenvironment and improve the efficacy of immunotherapy. Significance: Blocking sialylation augments antitumor immunity and enhances response to immune checkpoint blockade therapy, highlighting a potential therapeutic approach for treating patients with high-grade serous ovarian cancer.

Tumour-associated neutrophils orchestrate intratumoural IL-8-driven immune evasion through Jagged2 activation in ovarian cancer

Abstract Background Tumour associated neutrophils (TANs) play a controversial role in regulating immune surveillance and immune evasion in various malignancies. Here, we investigated the relevance of TANs with the prognosis and immune microenvironment of epithelial ovarian cancer (EOC). Methods We characterised TANs using flow cytometric analysis and immunofluorescence analysis. The prognostic merit of TANs in EOC was evaluated using cox regression analysis. Furthermore, we explored the therapeutic merit of targeting Notch signalling in EOC and determined its involvement in the immune microenvironment. Results High level of TANs is associated with a dismal prognosis and immune tolerance in EOC. TANs impaired cytotoxic effects of CD8+ T cells partly through Jagged2 (JAG2). Notch pathway blocked using γ-secretase inhibitor LY3039478 and anti-JAG2 antibody led to retarded tumour growth and augmented cytotoxic effects of CD8+ T cells. IL-8 contributes to the recruitment of TANs and the induction of JAG2 expression in TANs. Blockade of CXCR2 signalling reduces tumour growth rate, accompanied by a decreasing amount of TANs and increasing activity of CD8+ T cells. JAG2+TANs is an independent predictor of clinical outcomes. Conclusion JAG2+TANs are closely linked to IL-8-driven immune evasion microenvironment and may serve as a promising therapeutic target for the reinvigoration of anti-tumour immunity.

The prognostic significance of tumor-infiltrating lymphocytes in cervical cancer

To predict the prognosis of cervical cancer, we constructed a novel model with 5 specific cell types and identified a potential biomarker. We employed CIBERSORT and xCell method to evaluate the abundances of 23 cells types in tumor microenvironment. Five specific cell types were filtrated to determine different immunotypes by applying least absolute shrinkage and selection operator (LASSO) Cox regression method. The expression of immune checkpoints (ICPs) and effectors were validated by immunohistochemistry. Correlation analysis was performed to examine the relevance between PIK3CA mutational status and ICPs. Unsupervised clustering of patients on the basis of tumor infiltrating lymphocytes and fibroblasts identified patients with shorter overall survival (OS) (hazard ratio [HR]=3.0729; 95% confidence interval [CI]=1.5103-6.2522; p=0.0118). An immunoscore (IS) signature consisting of 5 immune cell types infiltrating in tumor core (CD8T, activated NK cells, neutrophils, activated mast cells, macrophages) was constructed using LASSO Cox regression analysis. Receiver operating characteristic curves confirmed that the area under the curve of IS was significantly higher to that of International Federation of Gynecology and Obstetrics staging alone (0.637 vs. 0.55). Survival analysis revealed patients in high IS group exhibited a poorer OS (HR=3.0113; 95% CI=1.8746-4.8373; p<0.0001). The multivariate analysis indicated the IS was an independent prognostic factor. In addition, the lower IS related to higher expression of ICPs and neoantigen load. The identification of IS in cervical cancer tissues could facilitate patient risk stratification and selection of immunotherapeutic responses, but more prospective studies are needed to assess its reliability.

The immune landscape during the tumorigenesis of cervical cancer

AbstractObjectiveDeciphering the determinants of the intralesional immune reaction in cervical carcinogenesis may be conducive to improving the understanding of the disease and then improve outcomes.MethodsPublic gene‐expression data and full clinical annotation were searched in Gene Expression Omnibus in the joint analysis of the array‐based four eligible cohorts. The infiltrating estimation was quantified using microenvironment cell populations‐counter algorithm and absolute‐mode CIBERSORT and verified by flow cytometry analysis. An unsupervised classification on immune genes strongly associated with progression, designated by linear mixed‐effects regression. We determined immune response and signaling features of the different developmental stages and immune phenotypes by functional annotation and systematically correlated the expression of immune checkpoints with cell‐infiltrating characteristics.ResultsWe identified the lesion‐intrinsic immunosuppression mechanism was triggered at precancerous stages, such as genome instability and mutation, aerobic glycolysis, activation of proto‐oncogene pathways and so forth. Predominant innate and adoptive cells were increasing from normalcy to cancer (B cell, total T cell, regulatory T cells [Tregs], monocytes, neutrophils, and M2‐like macrophages) together with the decrease of CD4+ T cell and CD8+ T cell through the development of cervical cancer. Immune escape initiated on the expression of immunosuppressive molecules from high‐grade squamous intraepithelial lesions (HSIL) and culminated in squamous cell carcinoma (SCC). Of note, the expression of immune checkpoints was escalated in the immune‐hot and immune‐warm phenotype largely encompassed by HSIL and SCC under the stress of both activated and suppressive immune responses.ConclusionsImmune surveillance is unleashing from low‐grade squamous intraepithelial lesions onwards and immune‐suppression mechanisms are triggered in HSIL. Thorough knowledge of the immune changing pattern during cervical tumorigenesis contributes to finding the potential therapeutic targets to susceptive patients towards immune checkpoints inhibitors.