The Tumor Immune Contexture of Prostate Cancer.

One in seven men in North America is expected to be diagnosed with prostate cancer (PCa) during their lifetime (1, 2). While a wide range of treatment options including surgery, radiation, androgen deprivation and chemotherapy have been in practice for the last few decades, there are limited treatment options for metastatic and treatment resistant disease. Immunotherapy targeting T-cell associated immune checkpoints such as CTLA-4, PD-L1, and PD-1 have not yet proven to be efficacious in PCa. Tumor mutational burden, mutations in DNA damage repair genes, immune cell composition and density in combination with their spatial organization, and expression of immune checkpoint proteins are some of the factors influencing the success of immune checkpoint inhibitor therapies. The paucity of these features in PCa potentially makes them unresponsive to contemporary immune checkpoint inhibition. In this review, we highlight the hallmark events in the PCa tumor immune microenvironment and provide insights into the current state of knowledge in this field with a focus on the role of tumor cell intrinsic events that potentially regulate immune related events and determine therapeutic outcomes. We surmise that the cumulative impact of factors such as the pre-treatment immune status, PTEN expression, DNA damage repair gene mutations, and the effects of conventionally used treatments on the anti-tumor immune response should be considered in immunotherapy trial design in PCa.

MYC Protein Interactome Profiling Reveals Functionally Distinct Regions that Cooperate to Drive Tumorigenesis.

Transforming members of the MYC family (MYC, MYCL1, and MYCN) encode transcription factors containing six highly conserved regions, termed MYC homology boxes (MBs). By conducting proteomic profiling of the MB interactomes, we demonstrate that half of the MYC interactors require one or more MBs for binding. Comprehensive phenotypic analyses reveal that two MBs, MB0 and MBII, are universally required for transformation. MBII mediates interactions with acetyltransferase-containing complexes, enabling histone acetylation, and is essential for MYC-dependent tumor initiation. By contrast, MB0 mediates interactions with transcription elongation factors via direct binding to the general transcription factor TFIIF. MB0 is dispensable for tumor initiation but is a major accelerator of tumor growth. Notably, the full transforming activity of MYC can be restored by co-expression of the non-transforming MB0 and MBII deletion proteins, indicating that these two regions confer separate molecular functions, both of which are required for oncogenic MYC activity.

STING agonist therapy in combination with PD-1 immune checkpoint blockade enhances response to carboplatin chemotherapy in high-grade serous ovarian cancer.

BACKGROUND: High-grade serous carcinoma (HGSC) of the ovary is predominantly diagnosed at late stages and primarily treated with debulking surgery followed by platinum/taxane-based chemotherapy. Although certain patients benefit significantly from currently used chemotherapy, there are patients who either do not respond or have an inadequate duration of response. We previously showed that tumours from chemoresistant patients have an immunosuppressed pre-existing tumour immune microenvironment with decreased expression of Type I Interferon (IFN1) genes. METHODS: Efficacy of a 'STimulator of INterferon Genes' agonist was evaluated in combination with carboplatin chemotherapy and PD-1 immune checkpoint blockade therapy in the ID8-Trp53-/- immunocompetent murine model of HGSC. RESULTS: Treatment with STING agonist led to decreased ascites accumulation and decreased tumour burden. Survival of mice treated with a combination of carboplatin, STING agonist and anti-PD-1 antibody was the longest. Tumour immune transcriptomic profiling revealed higher IFN response, antigen presentation and MHC II genes in tumours from STING agonist-treated mice compared to vehicle controls. Flow cytometry analysis revealed significantly higher intra-tumoural PD-1+ and CD69+CD62L-, CD8+ T cells in STING agonist-treated mice. CONCLUSIONS: These findings will enable rational design of clinical trials aimed at combinatorial approaches to improve chemotherapy response and survival in HGSC patients.

Multi-omics in high-grade serous ovarian cancer: Biomarkers from genome to the immunome.

Epithelial ovarian cancer (EOC) is a lethal gynaecological disease that imposes significant burden on health care and patient quality of life. High-grade serous carcinoma of the ovary (HGSC) is the most prevalent histological type of EOC. A vast majority of HGSC cases are diagnosed at late stages of the disease, limiting the opportunity for clinical intervention and resulting in a 10-year survival rate of <20%. Recent innovations in high-throughput molecular analysis of patient-derived specimens may address these clinical challenges by providing an enhanced understanding of the molecular aetiology of ovarian cancer, in addition to offering several opportunities for rational biomarker and targeted therapy discovery. In this review, we highlight the most significant contributions of omics approaches and how the advent of immunomics can aid in personalized combination chemo-immunotherapy in ovarian cancer treatment. We further provide insights into immunogenomic correlates of pre-treatment tumour immune microenvironment and some of the potential interpretations of immunomic data that require further validation, based on stromal and immune contributions to biomarker signatures. We believe a comprehensive integrative approach via meta-analysis of large ovarian cancer molecular profiling data sets is urgently needed to define robust prognostic and predictive classifiers of disease progression and treatment response. These investigations will inform rationalized biomarker-driven combination chemo-immunotherapy trials for improving response and survival of ovarian cancer patients.