Acquired resistance to selective estrogen receptor (ER) modulators (SERM) and downregulators (SERD) is a significant clinical problem in the treatment of estrogen (E2) receptor-positive (ER þ ) breast cancers. There are two ER subtypes, ERa and ERb, which promote and inhibit breast cancer cell proliferation, respectively. Although ER þ breast cancers typically express a high ratio of ERa to ERb, the acquisition of SERM resistance in vitro and in vivo is associated with increased relative expression of the ERb. On some gene enhancers, ERb has been shown to function in opposition to the ERa in the presence of E2. Here, we demonstrate that two different ERb agonists, WAY-20070 and a novel "A-CD" estrogen called L17, produce a marked reduction in G 2 -M phase correlated with effects on cyclin D1 and cyclin E expression in a SERM/SERD-resistant breast cancer cell line. ERb agonists recruited both the ERa and ERb to the Bcl-2 E2-response element strongly reducing Bcl-2 mRNA and protein in an ERb-dependent manner. L17 recruited RIP140 to the Bcl-2 promoter in cells overexpressing ERb. Exposure to the ERb ligands also resulted in increased processing of LC3-I to LC3-II, indicative of enhanced autophagic flux. The coaddition of ERb agonist and the autophagy inhibitor chloroquine resulted in a significant accumulation of sub-G 1 DNA which was completely prevented by the addition of the caspase inhibitor Z-VAD-FMK. We propose that combined therapies with an ERb agonist and an inhibitor of autophagy may provide the basis for a novel approach to the treatment of SERM/SERD-resistant breast cancers. Mol Cancer Ther; 13(7); 1882-93. Ó2014 AACR.
Long-term use of estrogen supplements by women leads to an increased risk of breast and uterine cancers. Possible mechanisms include metabolism of estradiol and compounds related to tumor-initiating quinones, and ligand-induced activation of the estrogen receptors ERα and ERβ which can cause cancer cell proliferation, depending on the ratio of receptors present. One therapeutic goal would be to create a spectrum of compounds of variable potency for ERα and ERβ, which are resistant to quinone formation, and to determine an optimum point in this spectrum. We describe the synthesis, modeling, binding affinities, hormone potency, and a measure of quinone formation for a new family of A-CD estrogens, where the A-C bond is formed by ring coupling. Some substituents on the A-ring increase hormone potency, and one compound is much less quinone-forming than estradiol. These compounds span a wide range of receptor subtype selectivities and may be useful in hormone replacement therapy.
Based on the RECOVERY trial, glucocorticoids have become the mainstay of treatment for COVID-19, thus increasing the risk of opportunistic infections. We report a case of disseminated
Cryptococcus neoformans
with documented meningoencephalitis in a patient with severe COVID-19 in the setting of prolonged glucocorticoids administration with poor outcome likely due to adrenal involvement.
Vasomotor thermo-dysregulation (hot flashes) are an often debilitating symptom of menopause. Effective treatment is achieved primarily through activation of the estrogen receptor (ER)α with estrogens but is also associated with increased risk for breast and uterine cancer. In this study, we have tested novel compounds lacking the B ring of 17-hydroxy-β-estradiol (E2) (A-CD compounds) with differing ratios of ERα:ERβ binding affinities for the ability to reduce diurnal/nocturnal tail-skin temperatures (TSTs) in the ovariectomized female rat menopausal hot flash model. Normal mammary tissue expresses the predominantly antiproliferative ERβ. Therefore, we hypothesized that a preferential ERβ agonist with fractional ERα activity would safely reduce TSTs. The A-CD compound, L17, is a preferential ERβ agonist that has a ratio of ERβ:ERα binding affinity relative to E2 of 9.3 (where ERβ:ERα for E2, 1.0). In the ovariectomized rat, daily administration of low doses (1 mg/kg) of the A-CD compound TD81 (ERα:ERβ relative affinity, 15.2) was ineffective in temperature regulation, whereas L17 showed a trend toward TST reduction. Both E2 and the A-CD compound, TD3 (ERβ:ERα relative affinity, 5.0), also reduced TSTs but had marked proliferative effects on mammary and uterine tissues. At 2 mg/kg, L17 strongly reduced TSTs even more effectively than E2 but, importantly, had only minimal effect on uterine weight and mammary tissues. Both E2- and L17-treated rats showed similar weight reduction over the treatment period. E2 is rapidly metabolized to highly reactive quinones, and we show that L17 has 2-fold greater metabolic stability than E2. Finally, L17 and E2 similarly mediated induction of c-fos expression in neurons within the rat thermoregulatory hypothalamic median preoptic nucleus. Thus, the A-CD compound, L17, may represent a safe and effective approach to the treatment of menopausal hot flashes.
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