an-immunohistopathologic-study-to-profile-folate-receptor-beta

An Immunohistopathologic Study to Profile the Folate Receptor Beta Macrophage and Vascular Immune Microenvironment in Giant Cell Arteritis

Giant cell arteritis (GCA) is a chronic immune-mediated disease of medium-to-large sized arteries that affects older adults. GCA manifests with arthritis ...

Wayne State University School of Medicine

Distal metastasis of luminal breast cancer is frequent and incurable, yet the metastasis mechanisms are poorly understood. Estrogen, even at postmenopausal concentrations, suppresses invasiveness of luminal breast cancer cells through the estrogen receptor (ER). Invasive tumors overexpress the short progesterone receptor A (PR-A) isoform. Even at postmenopausal concentrations, progesterone activates PR-A, inducing invasiveness by counteracting estrogen's effects, particularly when cells are hypersensitized to progesterone by PR-A overexpression. To interrogate the role of this cross-talk in metastasis, we investigated selective cross-talk mechanisms of PR-A with ER. We developed a quantitative PCR-based lymph node infiltration assay to address the slowness of metastasis of tumor xenografts. We found that 15 microRNAs (miRNAs) are regulated by progesterone via PR-A, but not the longer PR-B isoform, with increased progesterone sensitivity when PR-A was overexpressed. Two of these miRNAs whose induction (miR-92a-3p) or repression (miR-26b-5p) by estrogen was suppressed by progesterone plus PR-A were critical for the PR-A-ER cross-talk causing a gene-regulatory pattern of invasiveness and metastasis and complete rescue of invasiveness  Constitutive expression of miR-92a-3p or inhibition of miR-26b-5p profoundly suppressed metastasis. Finally, in primary breast tumors, PR-A expression was correlated negatively with miR-92a-3p expression and positively with miR-26b-5p expression. Therefore, hormonal cross-talk of PR-A with ER is probably a fundamental mechanism that enables metastasis of luminal breast cancer. Moreover, miRNA biomarkers of hyperactive PR-A may help predict metastatic potential of luminal breast tumors. Further, miR-92a-3p and miR-26b-5p may reveal target pathways for selective intervention to suppress hormone-regulated metastasis, both pre- and postmenopause.

Progesterone receptor A promotes invasiveness and metastasis of luminal breast cancer by suppressing regulation of critical microRNAs by estrogen.

Testosterone suppression in prostate cancer is limited by serious side effects and resistance via restoration of androgen receptor (AR) functionality. ELK1 is required for AR-dependent growth in various hormone-dependent and castration-resistant prostate cancer models. The amino-terminal domain of AR docks at two sites on ELK1 to coactivate essential growth genes. This study explores the ability of small molecules to disrupt the ELK1-AR interaction in the spectrum of prostate cancer, inhibiting AR activity in a manner that would predict functional tumor selectivity.

Strategy for Tumor-Selective Disruption of Androgen Receptor Function in the Spectrum of Prostate Cancer.

Dexamethasone (Dex), co-administered to lung adenocarcinoma patients with pemetrexed chemotherapy, protects against pemetrexed cytotoxicity by inducing reversible G1 arrest, reflected by the effect of Dex on FLT-PET images of patient tumors. However, perioperative Dex treatment increases survival but the mechanism is unknown. In cells with glucocorticoid receptor-α (GR) expression corresponding to higher clinical tumor levels, Dex-induced growth arrest was followed by marked cell expansion, beta-galactosidase expression and Ki67 negativity, despite variable p53 and K-RAS status. Dex induced a transient early surge in p21. However, a progressive, irreversible loss of clonogenic growth, whose time of onset was dependent on GR level and Dex dose, was independent of p21and caused by gradual accumulation of p27 due to transcriptional activation of p27 by Dex. This effect was independent of canonical pathways of senescence or p27 regulation. The in vitro observations were reflected by growth suppression and P27 induction in GR-overexpressing tumor xenografts compared with isogenic low-GR tumors. Extended Dex treatment induces irreversible cell cycle blockade and a senescence phenotype through chronic activation of the p27 gene in GR overexpressing lung tumor cell populations and hence could improve outcome of surgery/pemetrexed chemotherapy and sensitize tumors to immunotherapy.

Chronic p27 Induction by Dexamethasone Causes Senescence Phenotype and Permanent Cell Cycle Blockade in Lung Adenocarcinoma Cells Over-expressing Glucocorticoid Receptor.

Article	Year
Progesterone receptor A promotes invasiveness and metastasis of luminal breast cancer by suppressing regulation of critical microRNAs by estrogen. The Journal of biological chemistry\| PubMed ID: 29162724	2018
Strategy for Tumor-Selective Disruption of Androgen Receptor Function in the Spectrum of Prostate Cancer. Clinical cancer research : an official journal of the American Association for Cancer Research\| PubMed ID: 30185422	2018
Chronic p27 Induction by Dexamethasone Causes Senescence Phenotype and Permanent Cell Cycle Blockade in Lung Adenocarcinoma Cells Over-expressing Glucocorticoid Receptor. Scientific reports\| PubMed ID: 30375484	2018

Manohar Ratnam

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