PURPOSE: Patients with high-grade serous ovarian carcinoma (HGSOC) are virtually insensitive to immune checkpoint inhibitors (ICI) employed as standalone therapeutics, at least in part reflecting microenvironmental immunosuppression. Thus, conventional chemotherapeutics and targeted anticancer agents that not only mediate cytotoxic effects but also promote the recruitment of immune effector cells to the HGSOC microenvironment stand out as promising combinatorial partners for ICIs in this oncological indication. EXPERIMENTAL DESIGN: We harnessed a variety of transcriptomic, spatial, and functional assays to characterize the differential impact of neoadjuvant paclitaxel-carboplatin on the immunological configuration of paired primary and metastatic HGSOC biopsies as compared to neoadjuvant chemotherapy (NACT)-naïve HGSOC samples from five independent patient cohorts. RESULTS: We found NACT-driven endoplasmic reticulum stress and calreticulin exposure in metastatic HGSOC lesions culminates with the establishment of a dense immune infiltrate including follicular T cells (TFH cells), a prerequisite for mature tertiary lymphoid structure (TLS) formation. In this context, TLS maturation was associated with an increased intratumoral density of ICI-sensitive TCF1+PD1+ CD8+ T cells over their ICI-insensitive TIM-3+PD1+ counterparts. Consistent with this notion, chemotherapy coupled with a PD1-targeting ICI provided a significant survival benefit over either therapeutic approach in syngeneic models of HGSOC bearing high (but not low) tumor mutational burden. CONCLUSIONS: Altogether, our findings suggest that NACT promotes TLS formation and maturation in HGSOC lesions, de facto preserving an intratumoral ICI-sensitive T-cell phenotype. These observations emphasize the role of rational design, especially relative to the administration schedule, for clinical trials testing chemotherapy plus ICIs in patients with HGSOC. See related commentary by Bravo Melgar and Laoui, p. 10.

• MeSH
• CD8-Positive T-Lymphocytes * immunology   drug effects   MeSH
• Tertiary Lymphoid Structures * immunology   pathology   MeSH
• Hepatocyte Nuclear Factor 1-alpha * genetics   metabolism   MeSH
• Immune Checkpoint Inhibitors * therapeutic use   pharmacology   MeSH
• Carboplatin administration & dosage   pharmacology   therapeutic use   MeSH
• Humans MeSH
• Tumor Microenvironment * immunology   drug effects   MeSH
• Ovarian Neoplasms * drug therapy   immunology   pathology   MeSH
• Neoadjuvant Therapy methods   MeSH
• Paclitaxel administration & dosage   therapeutic use   pharmacology   MeSH
• Antineoplastic Combined Chemotherapy Protocols therapeutic use   pharmacology   MeSH
• Cystadenocarcinoma, Serous drug therapy   pathology   immunology   MeSH
• Endoplasmic Reticulum Stress drug effects   immunology   MeSH
• Lymphocytes, Tumor-Infiltrating immunology   drug effects   metabolism   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Hepatocyte Nuclear Factor 1-alpha * MeSH
• Immune Checkpoint Inhibitors * MeSH
• Carboplatin MeSH
• Paclitaxel MeSH

Intratumoral tertiary lymphoid structures (TLSs) have been associated with improved outcome in various cohorts of patients with cancer, reflecting their contribution to the development of tumor-targeting immunity. Here, we demonstrate that high-grade serous ovarian carcinoma (HGSOC) contains distinct immune aggregates with varying degrees of organization and maturation. Specifically, mature TLSs (mTLS) as forming only in 16% of HGSOCs with relatively elevated tumor mutational burden (TMB) are associated with an increased intratumoral density of CD8+ effector T (TEFF) cells and TIM3+PD1+, hence poorly immune checkpoint inhibitor (ICI)-sensitive, CD8+ T cells. Conversely, CD8+ T cells from immunologically hot tumors like non-small cell lung carcinoma (NSCLC) are enriched in ICI-responsive TCF1+ PD1+ T cells. Spatial B-cell profiling identifies patterns of in situ maturation and differentiation associated with mTLSs. Moreover, B-cell depletion promotes signs of a dysfunctional CD8+ T cell compartment among tumor-infiltrating lymphocytes from freshly isolated HGSOC and NSCLC biopsies. Taken together, our data demonstrate that - at odds with NSCLC - HGSOC is associated with a low density of follicular helper T cells and thus develops a limited number of mTLS that might be insufficient to preserve a ICI-sensitive TCF1+PD1+ CD8+ T cell phenotype. These findings point to key quantitative and qualitative differences between mTLSs in ICI-responsive vs ICI-irresponsive neoplasms that may guide the development of alternative immunotherapies for patients with HGSOC.

• MeSH
• CD8-Positive T-Lymphocytes MeSH
• Tertiary Lymphoid Structures * MeSH
• Phenotype MeSH
• Humans MeSH
• Tumor Microenvironment MeSH
• Lung Neoplasms * MeSH
• Ovarian Neoplasms * pathology   MeSH
• Carcinoma, Non-Small-Cell Lung * MeSH
• Lymphocytes, Tumor-Infiltrating MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Epithelial ovarian cancer (EOC) is among the top five causes of cancer-related death in women, largely reflecting early, prediagnosis dissemination of malignant cells to the peritoneum. Despite improvements in medical therapies, particularly with the implementation of novel drugs targeting homologous recombination deficiency, the survival rates of patients with EOC remain low. Unlike other neoplasms, EOC remains relatively insensitive to immune checkpoint inhibitors, which is correlated with a tumor microenvironment (TME) characterized by poor infiltration by immune cells and active immunosuppression dominated by immune components with tumor-promoting properties, especially tumor-associated macrophages (TAMs). In recent years, TAMs have attracted interest as potential therapeutic targets by seeking to reverse the immunosuppression in the TME and enhance the clinical efficacy of immunotherapy. Here, we review the key biological features of TAMs that affect tumor progression and their relevance as potential targets for treating EOC. We especially focus on the therapies that might modulate the recruitment, polarization, survival, and functional properties of TAMs in the TME of EOC that can be harnessed to develop superior combinatorial regimens with immunotherapy for the clinical care of patients with EOC.

• Keywords
• Immunomodulation, Immunotherapy, Macrophages, Tumor Biomarkers, Tumor Microenvironment,
• MeSH
• Carcinoma, Ovarian Epithelial therapy   pathology   MeSH
• Immunotherapy MeSH
• Carcinoma * pathology   MeSH
• Humans MeSH
• Tumor-Associated Macrophages pathology   MeSH
• Macrophages MeSH
• Tumor Microenvironment MeSH
• Ovarian Neoplasms * MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

Epithelial ovarian carcinoma (EOC) is a relatively rare malignancy but is the fifth-leading cause of cancer-related death in women, largely reflecting early, prediagnosis dissemination of malignant disease to the peritoneum. At odds with other neoplasms, EOC is virtually insensitive to immune checkpoint inhibitors, correlating with a tumor microenvironment that exhibits poor infiltration by immune cells and active immunosuppression. Here, we comparatively summarize the humoral and cellular features of primary and metastatic EOC, comparatively analyze their impact on disease outcome, and propose measures to alter them in support of treatment sensitivity and superior patient survival.

• Keywords
• female, genital neoplasms, immunologic surveillance, immunotherapy, tumor biomarkers, tumor microenvironment,
• MeSH
• Carcinoma, Ovarian Epithelial immunology   MeSH
• Immunosuppression Therapy methods   MeSH
• Immunotherapy methods   MeSH
• Humans MeSH
• Tumor Microenvironment MeSH
• Treatment Outcome MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

LTX-315 is a nonameric oncolytic peptide in early clinical development for the treatment of solid malignancies. Preclinical and clinical evidence indicates that the anticancer properties of LTX-315 originate not only from its ability to selectively kill cancer cells, but also from its capacity to promote tumor-targeting immune responses. Here, we investigated the therapeutic activity and immunological correlates of intratumoral LTX-315 administration in three syngeneic mouse models of breast carcinoma, with a focus on the identification of possible combinatorial partners. We found that breast cancer control by LTX-315 is accompanied by a reconfiguration of the immunological tumor microenvironment that supports the activation of anticancer immunity and can be boosted by radiation therapy. Mechanistically, depletion of natural killer (NK) cells compromised the capacity of LTX-315 to limit local and systemic disease progression in a mouse model of triple-negative breast cancer, and to extend the survival of mice bearing hormone-accelerated, carcinogen-driven endogenous mammary carcinomas. Altogether, our data suggest that LTX-315 controls breast cancer progression by engaging NK cell-dependent immunity.

• Keywords
• CTLA4, MPA/DMBA-driven mammary carcinomas, PD-1, TS/A cells, cDC1s, immune checkpoint inhibitors,
• MeSH
• Killer Cells, Natural MeSH
• Immunotherapy MeSH
• Humans MeSH
• Mice MeSH
• Tumor Microenvironment MeSH
• Oligopeptides * MeSH
• Triple Negative Breast Neoplasms * therapy   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• LTX-315 MeSH Browser
• Oligopeptides * MeSH