Forkhead box A2 (FOXA2) and fibroblast growth factor two (FGFR2) in female reproductive tract development

A functional female reproductive tract (FRT) is fundamental to fertility in mammals since it provides the niche for fertilization, embryo implantation, and fetal development. Organogenesis of the FRT progresses from a pair of embryonic Müllerian ducts (MD) and is complete at birth; however, the uterus is not fully differentiated at birth, particularly lacking glands of the endometrium. During the first two weeks of postnatal life, the FRT undergoes morphogenesis to ensure proper organization and reach full functional capacity. There remain significant gaps in our knowledge of the molecular mechanisms governing FRT development. Aims of this thesis are: determine the role of forkhead box A2 (Foxa2) and fibroblast growth factor receptor two (Fgfr2) in the development of the FRT in mice. Those objectives were addressed by: (1) conditional deletion of Foxa2 and Fgfr2 using progesterone receptor (PGR) Cre recombinase in PGR expressing cells of the FRT after birth; and (2) conditional deletion of Foxa2 and Fgfr2 in epithelial cells of the fetal MD using wingless-type MMTV integration site family member 7A (Wnt7a) Cre recombinase. Results of these studies established that: (1) Foxa2 is required for gland development; (2) Fgfr2 is required to maintain uterine epithelium morphology, and is involved in the outgrowth and development of the forelimb and hindlimb; and (3) loss of Fgfr2 using Wnt7aCre results in perinatal lethality, and may elicit feminization of the male external genitalia. Collectively, these results support the role for Foxa2 in postnatal uterine gland development, while Fgfr2 maintains the luminal epithelium identity in the uterus and is involved in limb outgrowth and phalange patterning; and male external genitalia differentiation in the fetus

Mobilization of pre-existing polyclonal T cells specific to neoantigens but not self-antigens during treatment of a patient with melanoma with bempegaldesleukin and nivolumab

T cells that recognize self-antigens and mutated neoantigens are thought to mediate antitumor activity of immune checkpoint blockade (ICB) in melanoma. Few studies have analyzed self and neoantigen-specific T cell responses in patients responding to ICB. Here, we report a patient with metastatic melanoma who had a durable clinical response after treatment with the programmed cell death protein 1 inhibitor, nivolumab, combined with the first-in-class CD122-preferential interleukin-2 pathway agonist, bempegaldesleukin (BEMPEG, NKTR-214). We used a combination of antigen-specific T cell expansion and measurement of interferon-γ secretion to identify multiple CD4+ and CD8+ T cell clones specific for neoantigens, lineage-specific antigens and cancer testis antigens in blood and tumor from this patient prior to and after therapy. Polyclonal CD4+ and CD8+ T cells specific to multiple neoantigens but not self-antigens were highly enriched in pretreatment tumor compared with peripheral blood. Neoantigen, but not self-antigen-specific T cell clones expanded in frequency in the blood during successful treatment. There was evidence of dramatic immune infiltration into the tumor on treatment, and a modest increase in the relative frequency of intratumoral neoantigen-specific T cells. These observations suggest that diverse CD8+ and CD4+ T cell clones specific for neoantigens present in tumor before treatment had a greater role in immune tumor rejection as compared with self-antigen-specific T cells in this patient. Trial registration number: NCT02983045

Neoantigen-specific CD4 + T cells in human melanoma have diverse differentiation states and correlate with CD8 + T cell, macrophage, and B cell function

CD4+ T cells that recognize tumor antigens are required for immune checkpoint inhibitor efficacy in murine models, but their contributions in human cancer are unclear. We used single-cell RNA sequencing and T cell receptor sequences to identify signatures and functional correlates of tumor-specific CD4+ T cells infiltrating human melanoma. Conventional CD4+ T cells that recognize tumor neoantigens express CXCL13 and are subdivided into clusters expressing memory and T follicular helper markers, and those expressing cytolytic markers, inhibitory receptors, and IFN-γ. The frequency of CXCL13+ CD4+ T cells in the tumor correlated with the transcriptional states of CD8+ T cells and macrophages, maturation of B cells, and patient survival. Similar correlations were observed in a breast cancer cohort. These results identify phenotypes and functional correlates of tumor-specific CD4+ T cells in melanoma and suggest the possibility of using such cells to modify the tumor microenvironment