Biology subjects

Lanz, R. B.

Publications and source records attributed to Lanz, R. B..

3 recordsLinked to original sources

bioRxiv2023

Steroid Receptor Coactivator-3 is a Key Modulator of Regulatory T Cell-Mediated Tumor Evasion

AbstractsSteroid receptor coactivator 3 (SRC-3) is most strongly expressed in regulatory T cells (Tregs) and B cells, suggesting that it plays an important role in the regulation of Treg function. Using an aggressive E0771 mouse breast cell line syngeneic immune-intact murine model, we observed that breast tumors were permanently eradicated in a genetically engineered tamoxifen-inducible Treg-cell specific SRC-3 knockout (KO) female mouse that does not possess a systemic autoimmune pathological phenotype. A similar eradication of tumor was noted in a syngeneic model of prostate cancer. A subsequent injection of additional E0771 cancer cells into these mice showed continued resistance to tumor development without the need for tamoxifen induction to produce additional SRC-3 KO Tregs. SRC-3 KO Tregs were highly proliferative and preferentially infiltrated into breast tumors by activating the Chemokine (C-C motif) ligand (Ccl) 19/Ccl21/ Chemokine (C-C motif) Receptor (Ccr)7 signaling axis, generating antitumor immunity by enhancing the interferon-{gamma}/C-X-C Motif Chemokine Ligand (Cxcl) 9 signaling axis to facilitate the entrance and function of effector T cells and Natural Killer cells. SRC-3 KO Tregs also show a dominant effect by blocking the immune suppressive function of WT Tregs. Importantly, a single adoptive transfer of SRC-3 KO Tregs into wild-type E0771 tumor-bearing mice can completely abolish pre-established breast tumors by generating potent antitumor immunity with a durable effect that prevents tumor reoccurrence. Therefore, treatment with SRC-3 deleted Tregs represents a novel approach to completely block tumor growth and recurrence without the autoimmune side-effects that typically accompany immune checkpoint modulators. Significance statementTregs are essential in restraining immune responses for immune homeostasis. SRC-3 is a pleiotropic coactivator, the second-most highly expressed transcriptional coactivator in Tregs, and a suspect in Treg function. The disruption of SRC-3 expression in Tregs leads to a complete lifetime eradication of tumors in aggressive syngeneic breast cancer mouse models because deletion of SRC-3 alters the expression of a wide range of key genes involved in efferent and afferent Treg signaling. SRC-3KO Tregs confer this long-lasting protection against cancer recurrence in mice without an apparent systemic autoimmune pathological phenotype. Therefore, treatment with SRC-3 deleted Tregs could represent a novel and efficient future target for eliminating tumor growth and recurrence without the autoimmune side-effects that typically accompany immune checkpoint modulators.

cancer biology↗

bioRxiv2020

SOX7 deficiency causes ventricular sepal defects through its effects on endocardial-to-mesenchymal transition and the expression of Wnt4 and Bmp2

SOX7 is located in a region on chromosome 8p23.1 that is recurrently deleted in individuals with septal defects. Sox7-/- embryos die of heart failure around E11.5 due to defects in vascular remodeling. These embryos have hypocellular endocardial cushions with severely reduced numbers of mesenchymal cells. We also observed a ventricular septal defect in a rare Sox7flox/-;Tie2-Cre embryo that escaped early lethality. This led us to hypothesize that SOX7 plays a critical developmental role in the endocardium of the atrioventricular (AV) canal. We subsequently used AV explant studies to show that SOX7 deficiency leads to a severe reduction in endocardial-to-mesenchymal transition (EndMT). Since SOX7 is a transcription factor, we hypothesized that it functions in the endocardium by regulating the expression of EndMT-related genes. To identify these genes in an unbiased manner, we performed RNA-seq on pooled E9.5 hearts tubes harvested from Sox7-/- embryos and their wild-type littermates. We found that Wnt4 transcript levels were severely reduced, which we confirmed by RNA in situ hybridization. Previous studies have shown that WNT4 is expressed in the endocardium and promotes EndMT by acting in a paracrine manner to increase the expression of BMP2 in the myocardium. Consistent with these findings, we found that Bmp2 transcript levels were diminished in Sox7-/- embryonic hearts. We conclude that SOX7 promotes EndMT in the developing AV canal by modulating the expression of Wnt4 and Bmp2. These data also provide additional evidence that haploinsufficiency of SOX7 contributes to the congenital heart defects seen in individuals with recurrent 8p23.1 microdeletions. SUMMARY STATEMENTIn the developing atrioventricular canal, SOX7 promotes endocardial-to-mesenchymal transition (EndMT) by positively regulating Wnt4 and Bmp2 expression. SOX7 deficiency leads to the development of hypocellular endothelial cushions and ventricular septal defects.

developmental biology↗

bioRxiv2019

Constitutive Expression of the Progesterone Receptor Isoforms Promotes Hormone-Dependent Development of Ovarian Neoplasms

Abnormal expression of the progesterone receptor (PGR) isoforms, PGRA and PGRB, is often observed in women with reproductive tract cancer. To assess the importance of the PGR isoform ratio in the maintenance of the healthy reproductive tract, mice with Cre recombinase- activated PGRA and PGRB transgenes were bred with the PGRCre mouse model to generate strains expressing either PGRA or PGRB in PGR positive tissues. The PGRB mice developed ovarian neoplasms at 23 weeks of age derived from ovarian luteal cells, while the PGRA expressing mice displayed a reduced frequency of tumor development. Transcriptomic analyses of the ovarian tumors revealed an enhanced AKT pathway signature, which is in agreement with expression changes found in human ovarian adenocarcinoma. Effective treatment with the PGR antagonist RU486 reduced tumor growth and the expression of cell cycle genes. We concluded that tumor growth and proliferation is hormone and PGR isoform dependent. Further analysis of the PGRB cistrome identified binding events of critical mitotic phase entry genes. This work suggests an intriguing mechanism whereby the expression of the PGR isoforms determines in vivo neoplasia through high-jacking of the cell cycle pathway.

cancer biology↗