A conserved function of Human DLC3 and Drosophila Cv-c in testis development

The identification of genes affecting gonad development is essential to understand the mechanisms causing Variations/Differences in Sex Development (DSD). Recently, a DLC3 mutation was associated with male gonadal dysgenesis in 46,XY DSD patients. We have studied the requirement of Cv-c, the Drosophila ortholog of DLC3, in Drosophila gonad development, as well as the functional capacity of DLC3 human variants to rescue cv-c gonad defects. We show that Cv-c is required to maintain testis integrity during fly development. We find that Cv-c and human DLC3 can perform the same function in fly embryos, as flies carrying wild type but not patient DLC3 variations can rescue gonadal dysgenesis, suggesting functional conservation. We also demonstrate that the StART domain mediates Cv-c's function in the male gonad independently from the GAP domain's activity. This work demonstrates a role for DLC3/Cv-c in male gonadogenesis and highlights a novel StART domain mediated function required to organize the gonadal mesoderm and maintain its interaction with the germ cells during testis development.This work was supported by María de Maeztu Unit excellence grants MDM-2016-0687 and CEX2020-001088 M and a Ministerio de Ciencia e Innovación grant PID2019-104656GB-I00 cofunded by the European Regional Development Fund (FEDER) to JC-GH. SV acknowledges support from the Swiss National Science Foundation (PP00P3_194807). This work was also supported by grants from the Swiss National Supercomputing Centre under project ID s1132 and has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 803952). AL-B acknowledges support from the Swiss National Science Foundation’s Grant 320030-184807. LL acknowledges support from the Swiss National Science Foundation (grant number SCOPES IZ73Z0_152347/1) and National Academy of Sciences of Ukraine, project 'Molecular-Genetic Mechanisms of Human Disorders of Sexual Development' [0121U110054]: With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (referencia del instituto). Por ejemplo: With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2020-001088)

DLC3/Cv-c function in testis development in humans and Drosophila: implication for variants of sex development

Identifying genes affecting gonad development is essential to understand the mechanisms causing Variants/Differences in Sex Development. Recently, a DLC3 mutation was associated with male gonadal dysgenesis in 46,XY DSD patients. We show that Cv-c, the Drosophila ortholog of DLC3, is also required to maintain testis integrity during fly development. We found that Cv-c and human DLC3 can perform the same function in fly embryos, as flies with wild type but not mutated DLC3 rescue gonadal dysgenesis, suggesting a functional conservation. Expression of different Cv-c protein variants demonstrated that the StART domain mediates the Cv-c function in the male gonad, independently from the GAP domain activity. This work demonstrates a role for DLC3/Cv-c in male gonadogenesis and highlights a novel StART-mediated function required for gonadal mesoderm-germ cell interaction during testis development

Metabolism of estrogens

High-grade serous ovarian cancer (HGSOC) is currently treated with cytoreductive surgery and platinum-based chemotherapy. The majority of patients show a primary responsehowever, many rapidly develop drug resistance. Antiestrogens have been studied as low toxic treatment options for HGSOC, with higher response rates in platinum-sensitive cases. Mechanisms for this difference in response remain unknown. Therefore, the present study investigated the impact of platinum resistance on steroid metabolism in six established HGSOC cell lines sensitive and resistant against carboplatin using a high-resolution mass spectrometry assay to simultaneously quantify the ten main steroids of the estrogenic metabolic pathway. An up to 60-fold higher formation of steroid hormones and their sulfated or glucuronidated metabolites was observed in carboplatin-sensitive cells, which was reversible by treatment with interleukin-6 (IL-6). Conversely, treatment of carboplatin-resistant cells expressing high levels of endogenous IL-6 with the monoclonal anti-IL-6R antibody tocilizumab changed their status to "platinum-sensitive", exhibiting a decreased IC$_{50}$ value for carboplatin, decreased growth, and significantly higher estrogen metabolism. Analysis of these metabolic differences could help to detect platinum resistance in HGSOC patients earlier, there by allowing more efficient interventions

Changes in the Tumor Immune Microenvironment during Disease Progression in Patients with Ovarian Cancer

Anti-PD1/PDL1 therapy has proven efficacious against many cancers but only reached modest objective response rates against recurrent ovarian cancer. A deeper understanding of the tumor microenvironment (TME) may reveal other immunosuppressive mechanisms that warrant investigation as immunotherapeutic targets for this challenging disease. Matched primary and recurrent tumors from patients with high-grade serous ovarian carcinoma (HGSC) were analyzed by multicolor immunohistochemistry/immunofluorescence for the presence of T cells, B cells, macrophages, and for the expression of immunosuppressive and HLA molecules. Cancer- and immune-related gene expression was assessed by NanoString analysis. Recurrent tumors showed increased infiltration by immune cells, displayed higher expression of PDL1, IDO, and HLA molecules, and contained more stromal tissue. NanoString analysis demonstrated increased expression of gene signatures related to chemokines and T cell functions in recurrent tumors. The ovarian tumors showed high gene expression of LAG3 and HAVCR2 (TIM3) and enhanced levels of TIGIT and CTLA4 in recurrent tumors compared to primary tumors. The majority of HGSC developed into a more inflamed phenotype during progression from primary to recurrent disease, including indications of adaptive immune resistance. This suggests that recurrent tumors may be particularly sensitive to inhibition of adaptive immune resistance mechanisms.Medicine, Faculty ofNon UBCMedical Genetics, Department ofObstetrics and Gynaecology, Department ofReviewedFacult