Recurrent estrogen receptor α (ERα)-positive breast and ovarian cancers are often therapy resistant. Using screening and functional validation, we identified BHPI, a potent noncompetitive small molecule ERα biomodulator that selectively blocks proliferation of drug-resistant ERα-positive breast and ovarian cancer cells. In a mouse xenograft model of breast cancer, BHPI induced rapid and substantial tumor regression. Whereas BHPI potently inhibits nuclear estrogen-ERα-regulated gene expression, BHPI is effective because it elicits sustained ERα-dependent activation of the endoplasmic reticulum (EnR) stress sensor, the unfolded protein response (UPR), and persistent inhibition of protein synthesis. BHPI distorts a newly described action of estrogen-ERα: mild and transient UPR activation. In contrast, BHPI elicits massive and sustained UPR activation, converting the UPR from protective to toxic. In ERα + cancer cells, BHPI rapidly hyperactivates plasma membrane PLCγ, generating inositol 1,4,5-triphosphate (IP 3 ), which opens EnR IP 3 R calcium channels, rapidly depleting EnR Ca 2+ stores. This leads to activation of all three arms of the UPR. Activation of the PERK arm stimulates phosphorylation of eukaryotic initiation factor 2α (eIF2α), resulting in rapid inhibition of protein synthesis. The cell attempts to restore EnR Ca 2+ levels, but the open EnR IP 3 R calcium channel leads to an ATP-depleting futile cycle, resulting in activation of the energy sensor AMP-activated protein kinase and phosphorylation of eukaryotic elongation factor 2 (eEF2). eEF2 phosphorylation inhibits protein synthesis at a second site. BHPI's novel mode of action, high potency, and effectiveness in therapyresistant tumor cells make it an exceptional candidate for further mechanistic and therapeutic exploration.estrogen receptor | drug discovery | breast cancer | unfolded protein response | ovarian cancer E strogens, acting via estrogen receptor α (ERα), stimulate tumor growth (1-3). Approximately 70% of breast cancers are ERα-positive and most deaths due to breast cancer are in patients with ERα + tumors (2, 4). Endocrine therapy using aromatase inhibitors to block estrogen production, or tamoxifen and other competitor antiestrogens, often results in selection and outgrowth of resistant tumors. Although 30-70% of epithelial ovarian tumors are ERα-positive (1), endocrine therapy is largely ineffective (5-7). After several cycles of chemotherapy, tumors recur as resistant ovarian cancer (5), and most patients die within 5 years (8).Noncompetitive ERα inhibitors targeting this unmet therapeutic need, including DIBA, TPBM, TPSF, and LRH-1 inhibitors that reduce ERα levels, show limited specificity, require high concentrations (>5 μM), and usually have not advanced through preclinical development (9-12). These noncompetitive ERα inhibitors and competitor antiestrogens are primarily cytostatic and act by preventing estrogen-ERα action; therefore, they are largely ineffective in therapy-resistant ERα containing cancer cells that no longer requi...
Lung cancer is the most common cause of cancer mortality worldwide. Non-small-cell lung carcinomas (NSCLCs), which represent around 80% of lung tumors, exhibit poor prognosis and are usually refractory to conventional chemotherapy. Elucidating the molecular and cellular mechanisms that are dysregulated in NSCLCs may lead to new possibilities for targeted therapy or enhanced efficacy of current therapies. Here we demonstrate Wnt pathway activation in around 50% of human NSCLC cell lines and primary tumors, through different mechanisms, including autocrine Wnt pathway activation involving upregulation of specific Wnt ligands. Downregulation of activated Wnt signaling inhibited NSCLC proliferation and induced a more differentiated phenotype. Together, our findings establish importance of activated Wnt signaling in human NSCLCs and offer the possibility of targeting upregulated Wnt signaling as a new therapeutic modality for this disease.
E-cigarettes have a liquid that may contain flavors, solvents, and nicotine. Heating this liquid generates an aerosol that is inhaled into the lungs in a process commonly referred to as vaping. E-cigarette devices can also contain cannabis-based products including tetrahydrocannabinol (THC), the psychoactive component of cannabis (marijuana). E-cigarette use has rapidly increased among current and former smokers as well as youth who have never smoked. The long-term health effects are unknown, and emerging preclinical and clinical studies suggest that e-cigarettes may not be harmless and can cause cellular alterations analogous to traditional tobacco smoke. Here, we review the historical context and the components of e-cigarettes and discuss toxicological similarities and differences between cigarette smoke and e-cigarette aerosol, with specific reference to adverse respiratory outcomes. Finally, we outline possible clinical disorders associated with vaping on pulmonary health and the recent escalation of acute lung injuries, which led to the declaration of the vaping product use-associated lung injury (EVALI) outbreak. It is clear there is much about vaping that is not understood. Consequently, until more is known about the health effects of vaping, individual factors that need to be taken into consideration include age, current and prior use of combustible tobacco products, and whether the user has preexisting lung conditions such as asthma and chronic obstructive pulmonary disease (COPD).
We randomize advertising content motivated by the psychology literature on sympathy generation and framing effects in mailings to about 185,000 prospective new donors in India. We find significant impact on the number of donors and amounts donated consistent with sympathy biases such as the "identifiable victim," "in-group" and "reference dependence." A monthly reframing of the ask amount increases donors and amount donated relative to daily reframing. A second field experiment targeted to past donors, finds that the effect of sympathy bias on giving is smaller in percentage terms but statistically and economically highly significant in terms of the magnitude of additional dollars raised. Methodologically, the paper complements the work of behavioral scholars by adopting an empirical researchers' lens of measuring relative effect sizes and economic relevance of multiple behavioral theoretical constructs in the sympathy bias and charity domain within one field setting. Beyond the benefit of conceptual replications, the effect sizes provide guidance to managers on which behavioral theories are most managerially and economically relevant when developing advertising content.
Estrogens, acting through estrogen receptor α (ERα), stimulate breast cancer proliferation, making ERα an attractive drug target. Since 384-well format screens for inhibitors of proliferation can be challenging for some cells, inhibition of luciferase-based reporters is often used as a surrogate end-point. To identify novel small molecules inhibitors of 17β-estradiol (E2)-ERα-stimulated cell proliferation, we established a cell-based screen for inhibitors of E2-ERα induction of an estrogen response element ((ERE)3-luciferase) reporter. 75 “hits” were evaluated in tiered follow-up assays to identify where hits failed to progress and evaluate their effectiveness as inhibitors of E2-ERα induced proliferation of breast cancer cells. Only 8 of 75 hits from the luciferase screen inhibited estrogen-induced proliferation of ERα positive MCF-7 and T47D cells, but not control ERα negative MDA-MB-231 cells. While 12% of compounds inhibited E2-ERα-stimulated proliferation in only one of the ERα positive cell lines, 40% of compounds were toxic and inhibited growth of all the cell lines, and ~37% exhibited little or no ability to inhibit E2-ERα-stimulated cell proliferation. Representative compounds were evaluated in more detail and a lead ERα inhibitor was identified.
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