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The International Tamoxifen Pharmacogenomics Consortium was established to address the controversy regarding cytochrome P450 2D6 (CYP2D6) status and clinical outcomes in tamoxifen therapy. We performed a meta-analysis on data from 4,973 tamoxifen-treated patients (12 globally distributed sites). Using strict eligibility requirements (postmenopausal women with estrogen receptor-positive breast cancer, receiving 20 mg/day tamoxifen for 5 years, criterion 1); CYP2D6 poor metabolizer status was associated with poorer invasive disease-free survival (IDFS: hazard ratio = 1.25; 95% confidence interval = 1.06, 1.47; P = 0.009). However, CYP2D6 status was not statistically significant when tamoxifen duration, menopausal status, and annual follow-up were not specified (criterion 2, n = 2,443; P = 0.25) or when no exclusions were applied (criterion 3, n = 4,935; P = 0.38). Although CYP2D6 is a strong predictor of IDFS using strict inclusion criteria, because the results are not robust to inclusion criteria (these were not defined a priori), prospective studies are necessary to fully establish the value of CYP2D6 genotyping in tamoxifen therapy.

Tamoxifen (TAM) has both cytostatic and cytotoxic properties for breast cancer. TAM engaged mitochondrial estrogen receptor beta (ERβ) as an antagonist in MCF7-BK cells, increasing reactive oxygen species (ROS) concentrations from the mitochondria that were required for cytotoxicity. In part, this derived from TAM downregulating manganese superoxide dismutase (MnSOD) activity by causing the nitrosylation of tyrosine 34, thereby increasing ROS. ROS-activated protein kinase C delta and c-jun N-terminal kinases, resulting in the mitochondrial translocation of Bax and cytochrome C release. Interestingly, TAM failed to cause high ROS levels or induce cell death in MCF7-BK-TR cells due to stimulation of MnSOD activity through agonistic effects at mitochondrial ERβ. In several mouse xenograft models, lentiviral shRNA-induced knockdown of MnSOD caused tumors that grew in the presence of TAM to undergo substantial apoptosis. Tumor MnSOD and mitochondrial ERβ are therefore targets for therapeutic intervention to reverse TAM resistance and enhance a cell death response.

Methylation has been shown to play an important role in the down-regulation of oestrogen receptors (ER) in breast cancer cells. One critical question that remains unclear is whether methylation can account for the loss of ER expression in cells derived from an ER-positive cell line. This laboratory has established an in vitro cell system using long-term growth of human ER-positive breast cancer cell line T47D in oestrogen-free medium. A clonal cell line, T47D:C4:2 (C4:2), has been characterized. Unlike T47D:A18 (A18), which is a T47D line maintained in oestrogen medium, C4:2 has lost the expression of ER and hormone responsiveness. DNA fingerprinting and restriction fragment length polymorphism (RFLP) analysis results confirmed that C4:2 was of the same lineage as A18. These cell lines provide an invaluable system to study the mechanism of ER expression and regulatory pathways leading to hormone-independent growth. The results here clearly demonstrate that the ER CpG island in C4:2 cells remains unmethylated. The loss of ER in the cell line must be due to mechanisms other than methylation. We also evaluated the ER CpG island in the MDA-MB-231:10A (10A) cell line, which is a clone from the MDA-MB-231 line obtained from ATCC and the DNA from the MDA-MB-231 cell line used in the original report. Unlike the cell line from the report, which showed a full methylation pattern in the island, the 10A line only showed a partial methylation pattern in the CpG island. Possible mechanisms pertaining to the heterogeneous methylation pattern of the ER CpG island in the breast cancer cells are discussed.

The completion of the Study of Tamoxifen and Raloxifene (STAR) [Vogel VG, Costantino JP, Wickerham DL, et al. The Study of Tamoxifen and Raloxifene (STAR): Report of the National Surgical Adjuvant Breast and Bowel Project P-2 Trial. JAMA 2006;295:2727-2741.] and the ongoing studies with aromatase inhibitors [Goss PE. Breast cancer prevention-clinical trials strategies involving aromatase inhibitors. J Steroid Biochem Mol Biol 2003;86(3-5):487-93.] to assess their worth for the chemoprevention of breast cancer, creates an opportunity to consider the realistic future for chemoprevention as an option for women's healthcare and to identify strategies for future progress in an era of targeted therapeutics, managed healthcare and soaring costs. [ABSTRACT FROM AUTHOR]

Context: Tamoxifen is approved for the reduction of breast cancer risk, and raloxifene has demonstrated a reduced risk of breast cancer in trials of older women with osteoporosis.Objective: To compare the relative effects and safety of raloxifene and tamoxifen on the risk of developing invasive breast cancer and other disease outcomes.Design, Setting, and Patients: The National Surgical Adjuvant Breast and Bowel Project Study of Tamoxifen and Raloxifene trial, a prospective, double-blind, randomized clinical trial conducted beginning July 1, 1999, in nearly 200 clinical centers throughout North America, with final analysis initiated after at least 327 incident invasive breast cancers were diagnosed. Patients were 19,747 postmenopausal women of mean age 58.5 years with increased 5-year breast cancer risk (mean risk, 4.03% [SD, 2.17%]). Data reported are based on a cutoff date of December 31, 2005.Intervention: Oral tamoxifen (20 mg/d) or raloxifene (60 mg/d) over 5 years.Main Outcome Measures: Incidence of invasive breast cancer, uterine cancer, noninvasive breast cancer, bone fractures, thromboembolic events.Results: There were 163 cases of invasive breast cancer in women assigned to tamoxifen and 168 in those assigned to raloxifene (incidence, 4.30 per 1000 vs 4.41 per 1000; risk ratio [RR], 1.02; 95% confidence interval [CI], 0.82-1.28). There were fewer cases of noninvasive breast cancer in the tamoxifen group (57 cases) than in the raloxifene group (80 cases) (incidence, 1.51 vs 2.11 per 1000; RR, 1.40; 95% CI, 0.98-2.00). There were 36 cases of uterine cancer with tamoxifen and 23 with raloxifene (RR, 0.62; 95% CI, 0.35-1.08). No differences were found for other invasive cancer sites, for ischemic heart disease events, or for stroke. Thromboembolic events occurred less often in the raloxifene group (RR, 0.70; 95% CI, 0.54-0.91). The number of osteoporotic fractures in the groups was similar. There were fewer cataracts (RR, 0.79; 95% CI, 0.68-0.92) and cataract surgeries (RR, 0.82; 95% CI, 0.68-0.99) in the women taking raloxifene. There was no difference in the total number of deaths (101 vs 96 for tamoxifen vs raloxifene) or in causes of death.Conclusions: Raloxifene is as effective as tamoxifen in reducing the risk of invasive breast cancer and has a lower risk of thromboembolic events and cataracts but a nonstatistically significant higher risk of noninvasive breast cancer. The risk of other cancers, fractures, ischemic heart disease, and stroke is similar for both drugs.Trial Registration: clinicaltrials.gov Identifier: NCT00003906. [ABSTRACT FROM AUTHOR]

Twenty years ago, antiestrogen therapy with tamoxifen played only a secondary role in breast cancer care. All hopes to cure metastatic breast cancer were still pinned on either the discovery of new cytotoxic drugs or a dose-dense combination of available cytotoxic drugs with bone marrow transplantation. A similar strategy with combination chemotherapy was employed as an adjuvant for primary breast cancer. Simply stated, the goal was to kill the cancer with nonspecific cytotoxic drugs while keeping the patient alive with supportive care. However, medical research does not travel in straight lines, and an alternative approach emerged to solve the problem of controlling tumor growth with minimal side effects: targeted therapy. The approach of using long-term antihormone therapy to control early-stage breast cancer growth would revolutionize cancer care by targeting the tumor estrogen receptor (ER). The success of the strategy would contribute to a decrease in the national mortality figures for breast cancer. More importantly, translational research that targeted the tumor ER with a range of new antiestrogenic drugs would presage the current fashion of blocking survival pathways for the tumor by developing novel targeted treatments. But a surprise was in store when the pharmacology of 'antiestrogens' was studied in detail: The nonsteroidal 'antiestrogens' are selective ER modulators'ie, they are antiestrogens in the breast, estrogens in the bone--and they lower circulating cholesterol levels. This knowledge would establish a practical approach to breast cancer chemoprevention for women at high risk (tamoxifen) and low risk (raloxifene). [ABSTRACT FROM AUTHOR]

Tamoxifen is the most widely used hormonal treatment for all stages of breast cancer and has been approved for the prevention of breast cancer in high-risk women. The observation that tamoxifen acts as an antioestrogen on the breast but has paradoxical oestrogenic effects on bones and lipids heralded the development of the selective oestrogen-receptor modulators (SERM). Raloxifene, another of these drugs, is being used to prevent osteoporosis in postmenopausal women, but it seems, like tamoxifen, to prevent breast cancer. The molecular basis for these target-site-specific actions remains unclear but may involve the relative expressions of coregulatory proteins in target tissues. Several new SERM agents are in clinical development in an attempt to decrease the unwanted effects. Furthermore, two different classes of hormonal agents, the aromatase inhibitors and oestrogen-receptor downregulators, which have no oestrogen-like properties at any site, are promising new treatments for breast cancer. [ABSTRACT FROM AUTHOR]

Context: Raloxifene hydrochloride is a selective estrogen receptor modulator that has antiestrogenic effects on breast and endometrial tissue and estrogenic effects on bone, lipid metabolism, and blood clotting.Objective: To determine whether women taking raloxifene have a lower risk of invasive breast cancer.Design and Setting: The Multiple Outcomes of Raloxifene Evaluation (MORE), a multicenter, randomized, double-blind trial, in which women taking raloxifene or placebo were followed up for a median of 40 months (SD, 3 years), from 1994 through 1998, at 180 clinical centers composed of community settings and medical practices in 25 countries, mainly in the United States and Europe.Participants: A total of 7705 postmenopausal women, younger than 81 (mean age, 66.5) years, with osteoporosis, defined by the presence of vertebral fractures or a femoral neck or spine T-score of at least 2.5 SDs below the mean for young healthy women. Almost all participants (96%) were white. Women who had a history of breast cancer or who were taking estrogen were excluded.Intervention: Raloxifene, 60 mg, 2 tablets daily; or raloxifene, 60 mg, 1 tablet daily and 1 placebo tablet; or 2 placebo tablets.Main Outcome Measures: New cases of breast cancer, confirmed by histopathology. Transvaginal ultrasonography was used to assess the endometrial effects of raloxifene in 1781 women. Deep vein thrombosis or pulmonary embolism were determined by chart review.Results: Thirteen cases of breast cancer were confirmed among the 5129 women assigned to raloxifene vs 27 among the 2576 women assigned to placebo (relative risk [RR], 0.24; 95% confidence interval [CI], 0.13-0.44; P<.001). To prevent 1 case of breast cancer, 126 women would need to be treated. Raloxifene decreased the risk of estrogen receptor-positive breast cancer by 90% (RR, 0.10; 95% CI, 0.04-0.24), but not estrogen receptor-negative invasive breast cancer (RR, 0.88; 95% CI, 0.26-3.0). Raloxifene increased the risk of venous thromboembolic disease (RR, 3.1; 95% CI, 1.5-6.2), but did not increase the risk of endometrial cancer (RR, 0.8; 95% CI, 0.2-2.7).Conclusion: Among postmenopausal women with osteoporosis, the risk of invasive breast cancer was decreased by 76% during 3 years of treatment with raloxifene. [ABSTRACT FROM AUTHOR]

PURPOSE: Tamoxifen, a selective oestrogen receptor modulator (SERM), and brivanib alaninate, a vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitor, are two target specific agents that result in a substantial decrease in tumour growth when given alone. Tamoxifen activates SERM stimulated breast and endometrial tumour growth. Tamoxifen and brivanib alaninate have side-effects that can affect therapeutic outcomes. The primary goal of the current study was to evaluate the therapeutic effects of lower doses of both agents when given in combination to mice with SERM sensitive, oestrogen stimulated tumour xenografts (MCF-7 E2 tumours). Experiments were conducted to evaluate the response of SERM stimulated breast (MCF-7 Tam, MCF-7 Ral) and endometrial tumours (EnCa 101) to demonstrate the activity of brivanib alaninate in SERM resistant models. EXPERIMENTAL DESIGN: In the current study, tumour xenografts were minced and bi-transplanted into the mammary fat pads of athymic, ovariectomised mice. Preliminary experiments were conducted to determine an effective oral dose of tamoxifen and brivanib alaninate that had minimal effect on tumour growth. Doses of 125 microg of tamoxifen and 0.05 mg/g of brivanib alaninate were evaluated. An experiment was designed to evaluate the effect of the two agents together when started at the time of tumour implantation. An additional experiment was done in which tumours were already established and then treated, to obtain enough tumour tissue for molecular analysis. RESULTS: Brivanib alaninate was effective at inhibiting tumour growth in SERM sensitive (MCF-7 E2) and SERM stimulated (EnCa 101, MCF-7 Ral, MCF-7 Tam) models. The effect of the low dose drug combination as an anti-tumour strategy for SERM sensitive (MCF-7 E2) in early treatment was as effective as higher doses of either drug used alone. In established tumours, the combination is successful at decreasing tumour growth, while neither agent alone is effective. Molecular analysis revealed a decreased phosphorylation of VEGFR-2 in tumours that were treated with brivanib alaninate and an increase in VEGFA transcription to compensate for the blockade of VEGFR-2 by increasing the transcription of VEGFA. Tamoxifen increases the phosphorylation of VEGFR-2 and this effect is abrogated by brivanib alaninate. There was also increased necrosis in tumours treated with brivanib alaninate. CONCLUSION: Historically, tamoxifen has a role in blocking angiogenesis as well as the blockade of the ER. Tamoxifen and a low dose of an angiogenesis inhibitor, brivanib alaninate, can potentially be combined not only to maximise therapeutic efficacy but also to retard SERM resistant tumour growth. [ABSTRACT FROM AUTHOR]

Purpose: Recently, we reported that exposure of prostate cells in vitro or the in vivo prostate to high glucose results in release of Zn 2+ ions, a process now referred to as glucose-stimulated zinc secretion (GSZS). To our knowledge, the metabolic event(s) that trigger GSZS remain largely unknown. Here, we explore several signaling pathways both in vitro using a prostate epithelial cell line and in vivo from the rat prostate., Methods: PNT1A cells grown to confluence were washed and tagged with ZIMIR to monitor zinc secretion by optical methods. The expression levels of GLUT1, GLUT4, and Akt in cells cultured in either zinc-rich or zinc-poor media and after exposure to high versus low glucose were determined. Zinc secretion from the rat prostate in vivo as detected by MRI was compared in control animals after injection of glucose, deoxyglucose, or pyruvate to initiate zinc secretion and in animals pre-treated with WZB-117 (a GLUT1 inhibitor) or S961 (a peripheral insulin receptor inhibitor)., Results: PNT1A cells exposed to high levels of glucose secrete zinc whereas cells exposed to an equivalent amount of deoxyglucose or pyruvate do not. Expression of Akt was dramatically altered by zinc supplementation of the culture media but not after exposure to glucose while GLUT1 and GLUT4 levels were less affected. Rats pre-treated with WZB-117 prior to imaging showed a reduction in GSZS from the prostate compared to controls whereas rats pre-treated with S961 showed no difference. Interestingly, in comparison to PNT1A cells, pyruvate and deoxyglucose also stimulate zinc secretion in vivo likely through indirect mechanisms., Conclusions: GSZS requires metabolism of glucose both in vitro (PNT1A cells) and in vivo (rat prostate). Pyruvate also stimulates zinc secretion in vivo but likely via an indirect pathway involving rapid production of glucose via gluconeogenesis. These combined results support the conclusion that glycolytic flux is required to trigger GSZS in vivo., (© 2023. The Author(s), under exclusive licence to World Molecular Imaging Society.)

Background & Aims: Many liver diseases are driven by inflammation, but imaging to non-invasively diagnose and quantify liver inflammation has been underdeveloped. The inflammatory liver microenvironment is aberrantly oxidising owing in part to reactive oxygen species generated by myeloid leucocytes. We hypothesised that magnetic resonance imaging using the oxidatively activated probe Fe-PyC3A will provide a non-invasive biomarker of liver inflammation., Methods: A mouse model of drug-induced liver injury was generated through intraperitoneal injection of a hepatoxic dose of acetaminophen. A mouse model of steatohepatitis was generated via a choline-deficient, l-amino acid defined high-fat diet (CDAHFD). Images were acquired dynamically before and after intravenous injection of Fe-PyC3A. The contrast agent gadoterate meglumine was used as a non-oxidatively activated negative control probe in mice fed CDAHFD. The (post-pre) Fe-PyC3A injection change in liver vs. muscle contrast-to-noise ratio (ΔCNR) recorded 2 min post-injection was correlated with liver function test values, histologic scoring assigned using the NASH Clinical Research Network criteria, and intrahepatic myeloid leucocyte composition determined by flow cytometry., Results: For mice receiving i.p. injections of acetaminophen, intrahepatic neutrophil composition correlated poorly with liver test values but positively and significantly with ΔCNR (r = 0.64, p <0.0001). For mice fed CDAHFD, ΔCNR generated by Fe-PyC3A in the left lobe was significantly greater in mice meeting histologic criteria strongly associated with a diagnosis NASH compared to mice where histology was consistent with likely non-NASH ( p  = 0.0001), whereas no differential effect was observed using gadoterate meglumine. In mice fed CDAHFD, ΔCNR did not correlate strongly with fractional composition of any specific myeloid cell subpopulation as determined by flow cytometry., Conclusions: Magnetic resonance imaging using Fe-PyC3A merits further evaluation as a non-invasive biomarker for liver inflammation., Impact and Implications: Non-invasive tests to diagnose and measure liver inflammation are underdeveloped. Inflammatory cells such as neutrophils release reactive oxygen species which creates an inflammatory liver microenvironment that can drive chemical oxidation. We recently invented a new class of magnetic resonance imaging probe that is made visible to the scanner only after chemical oxidation. Here, we demonstrate how this imaging technology could be applied as a non-invasive biomarker for liver inflammation., Competing Interests: EMG holds equity in, and receives consulting income from Reveal Pharmaceuticals, and receives consulting income from Collagen Medical, LLC. PC holds equity in, and receives consulting income from Collagen Medical LLC, holds equity in Reveal Pharmaceuticals, and has research funding from Takeda, Pliant Therapeutics, and Janssen. Please refer to the accompanying ICMJE disclosure forms for further details., (© 2023 The Authors.)

Many factors, including reproductive hormones, have been linked to a woman's risk of developing breast cancer (BC). We reviewed the literature regarding the relationship between ovulatory menstrual cycles (MCs) and BC risk. Physiological variations in the frequency of MCs and interference with MCs through genetic variations, pathological conditions and or pharmaceutical interventions revealed a strong link between BC risk and the lifetime number of MCs. A substantial reduction in BC risk is observed in situations without MCs. In genetic or transgender situations with normal female breasts and estrogens, but no progesterone (P4), the incidence of BC is very low, suggesting an essential role of P4. During the MC, P4 has a strong proliferative effect on normal breast epithelium, whereas estradiol (E2) has only a minimal effect. The origin of BC has been strongly linked to proliferation associated DNA replication errors, and the repeated stimulation of the breast epithelium by P4 with each MC is likely to impact the epithelial mutational burden. Long-lived cells, such as stem cells, present in the breast epithelium, can carry mutations forward for an extended period of time, and studies show that breast tumors tend to take decades to develop before detection. We therefore postulate that P4 is an important factor in a woman's lifetime risk of developing BC, and that breast tumors arising during hormonal contraception or after menopause, with or without menopausal hormone therapy, are the consequence of the outgrowth of pre-existing neoplastic lesions, eventually stimulated by estrogens and some progestins., (© 2023. The Author(s).)

Abstract: In 1971, Sir Alexander Haddow et al. delivered the inaugural David A. Karnofsky lecture at the American Society for Clinical Oncology. This award was designated American Society for Clinical Oncology's highest, as he had used translational research to identify the first clinical therapy, that is, synthetic estrogens to treat breast cancer. His lecture was entitled "Thoughts on Chemical Therapy." For 40 years, high-dose synthetic estrogens were used as palliative therapy, for some advanced breast cancer patients 5 years following menopause. Mechanisms were unknown. Tamoxifen, a failed "morning-after pill," is an antiestrogen in estrogen receptor-positive breast cancer, which was subsequently used to treat all stages of breast cancer and to prevent breast cancer. In 2008, Jordan was selected to present the 38th Karnofsky lecture entitled: "The Paradoxical Action of Estrogen in Breast Cancer-Survival or Death?" Unexpectedly, through a study of acquired resistance to long-term tamoxifen therapy, estrogen-induced apoptosis in long-term estrogen-deprived breast cancer was deciphered in Jordan's laboratory. These data and the biological rules established under laboratory conditions provided molecular mechanisms to aid in the interpretation of the Women's Health initiative in the United States and the Million Women Study in the United Kingdom. In addition, by establishing laboratory models to understand mechanisms of estrogen-induced apoptosis, new estrogen derivatives were successfully evaluated in the laboratory and tested as candidates for women after the therapeutic failure of antiestrogenic strategies to treat breast cancer. For the future, the knowledge obtained about estrogen-induced apoptosis in cancer holds the promise of discovering new therapies to control or cure cancer in general., Competing Interests: Conflicts of Interest and Sources of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. The Dallas/Fort Worth Living Legend Chair of Cancer Research, the George and Barbara Bush Endowment for Cancer Research, Specialized Program of Research Excellence in Breast Cancer Grant, CA-89018 (to V.C.J.), Department of Defense Center of Excellence Grant W81XWH-06-1-0590 (to V.C.J.), and NIH Cancer Center Core Grant NIH CA 16672 (principal investigator P. Pisters)., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Antiestrogen therapy of breast cancer has been a "gold standard" of treatment of estrogen receptor (ER)-positive breast cancer for decades. Resistance to antiestrogen therapy may develop, however, a vulnerability in long-term estrogen deprived (LTED) breast cancer cells was discovered. LTED breast cancer cells may undergo estrogen-induced apoptosis within a week of treatment with estrogen in vitro . This phenomenon has been also validated in vivo and in the clinic. The molecular ER-mediated mechanism of action of estrogen-induced apoptosis was deciphered, however, the relationship between the structure of estrogenic ligands and the activity of the ER in LTED breast cancer cells remained a mystery until recently. In this review we provide an overview of the structure-activity relationship of various estrogens with different chemical structures and the modulation of estrogen-induced apoptosis in LTED breast cancer cells resistant to antihormone therapy. We provide analysis of evidence gathered over more than a decade of structure-activity relationship studies by our group on the role of the change in the conformation of the estrogen receptor and the biological activities of different classes of estrogens and the receptor as well in LTED breast cancer., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Maximov, Fan, Abderrahman, Curpan and Jordan.)

Estrogen receptor α (ERα) is a target for the treatment of ER-positive breast cancer patients. Paradoxically, it is also the initial site for estrogen (E 2 ) to induce apoptosis in endocrine-resistant breast cancer. How ERα exhibits distinct functions, in different contexts, is the focus of numerous investigations. Compelling evidence demonstrated that unfolded protein response (UPR) is closely correlated with ER-positive breast cancer. Treatment with antiestrogens initially induces mild UPR through ERα with activation of three sensors of UPR-PRK-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6)-in the endoplasmic reticulum. Subsequently, these sensors interact with stress-associated transcription factors such as c-MYC, nuclear factor-κB (NF-κB), and hypoxia-inducible factor 1α (HIF1α), leading to acquired endocrine resistance. Paradoxically, E 2 further activates sustained secondary UPR via ERα to induce apoptosis in endocrine-resistant breast cancer. Specifically, PERK plays a key role in inducing apoptosis, whereas IRE1α and ATF6 are involved in endoplasmic reticulum stress-associated degradation after E 2 treatment. Furthermore, persistent activation of PERK deteriorates stress responses in mitochondria and triggers of NF-κB/tumor necrosis factor α (TNFα) axis, ultimately determining cell fate to apoptosis. The discovery of E 2 -induced apoptosis has clinical relevance for treatment of endocrine-resistant breast cancer. All of these findings demonstrate that ERα and associated UPR are double-edged swords in therapy for ER-positive breast cancer, depending on the duration and intensity of UPR stress. Herein, we address the mechanistic progress on how UPR leads to endocrine resistance and commits E 2 to inducing apoptosis in endocrine-resistant breast cancer., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The discovery of 17β-estradiol (E 2 )-induced apoptosis has clinical relevance. Mechanistically, E 2 over activates nuclear estrogen receptor α that results in stress responses. The unfolded protein response (UPR) is initiated by E 2 in the endoplasmic reticulum after hours of treatment in endocrine-resistant breast cancer cells, thereby activating three UPR sensors-PRK-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6) with different functions. Specifically, PERK plays a critical role in induction of apoptosis whereas IRE1α and ATF6 are involved in the endoplasmic reticulum stress-associated degradation (ERAD) of PI3K/Akt/mTOR pathways. In addition to attenuating protein translation, PERK increases the DNA-binding activity of NF-κB and subsequent TNFα expression. In addition, PERK communicates with the mitochondria to regulate oxidative stress at mitochondria-associated endoplasmic reticulum membranes (MAM). Furthermore, PERK is a component enriched in MAMs that interacts with multifunctional MAM-tethering proteins and integrally modulates the exchange of metabolites such as lipids, reactive oxygen species (ROS), and Ca 2+ at contact sites. MAMs are also critical sites for the initiation of autophagy to remove defective organelles and misfolded proteins through specific regulatory proteins. Thus, PERK conveys signals from nucleus to these membrane-structured organelles that form an interconnected network to regulate E 2 -induced apoptosis. Herein, we address the mechanistic progress on how PERK acts as a multifunctional molecule to commit E 2 to inducing apoptosis in endocrine-resistant breast cancer., (©2021 The Authors; Published by the American Association for Cancer Research.)

Background & Aims: During liver fibrosis, tissue repair mechanisms replace necrotic tissue with highly stabilized extracellular matrix proteins. Extracellular matrix stabilization influences the speed of tissue recovery. Here, we studied the expression and function of peroxidasin (PXDN), a peroxidase that uses hydrogen peroxide to cross-link collagen IV during liver fibrosis progression and regression., Methods: Mouse models of liver fibrosis and cirrhosis patients were analyzed for the expression of PXDN in liver and serum. Pxdn -/- and Pxdn +/+ mice were either treated with carbon tetrachloride for 6 weeks to generate toxin-induced fibrosis or fed with a choline-deficient L-amino acid-defined high-fat diet for 16 weeks to create nonalcoholic fatty liver disease fibrosis. Liver histology, quantitative real-time polymerase chain reaction, collagen content, flowcytometry and immunostaining of immune cells, RNA-sequencing, and liver function tests were analyzed. In vivo imaging of liver reactive oxygen species (ROS) was performed using a redox-active iron complex, Fe-PyC3A., Results: In human and mouse cirrhotic tissue, PXDN is expressed by stellate cells and is secreted into fibrotic areas. In patients with nonalcoholic fatty liver disease, serum levels of PXDN increased significantly. In both mouse models of liver fibrosis, PXDN deficiency resulted in elevated monocyte and pro-fibrolysis macrophage recruitment into fibrotic bands and caused decreased accumulation of cross-linked collagens. In Pxdn -/- mice, collagen fibers were loosely organized, an atypical phenotype that is reversible upon macrophage depletion. Elevated ROS in Pxdn -/- livers was observed, which can result in activation of hypoxic signaling cascades and may affect signaling pathways involved in macrophage polarization such as TNF-a via NF-kB. Fibrosis resolution in Pxdn -/- mice was associated with significant decrease in collagen content and improved liver function., Conclusion: PXDN deficiency is associated with increased ROS levels and a hypoxic liver microenvironment that can regulate recruitment and programming of pro-resolution macrophages. Our data implicate the importance of the liver microenvironment in macrophage programming during liver fibrosis and suggest a novel pathway that is involved in the resolution of scar tissue., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: This retrospective, about a single "mobile" laboratory in six locations on two continents, is intended as a case study in discovery for trainees and junior faculty in the medical sciences. Your knowledge of your topic is necessary to expect the unexpected., Historical Method: In 1972, there was no tamoxifen, only ICI 46, 474, a non-steroidal anti-estrogen with little chance of clinical development. No one would ever be foolish enough to predict that the medicine, 20 years later, would achieve legendary status as the first targeted treatment for breast cancer, and millions of women would benefit from long-term adjuvant tamoxifen therapy. The secret of tamoxifen's success was a translational research strategy proposed in the mid 1970's. This strategy was to treat only patients with estrogen receptor (ER)-positive breast cancer and deploy 5 or more years of adjuvant tamoxifen therapy to prevent recurrence. Additionally, tamoxifen prevented mammary cancer in animals. Could the medicine prevent breast cancer in women?, Results: Tamoxifen and the failed breast cancer drug raloxifene became the first selective estrogen receptor modulators (SERMs): a new drug group, discovered at the University of Wisconsin, Comprehensive Cancer Center. Serendipity can play a fundamental role in discovery, but there must be a rigorous preparation for the investigator to appreciate the possibility of a pending discovery. This article follows the unanticipated discoveries when PhD students "get the wrong answer." The secret of success of my six Tamoxifen Teams was their technical excellence to create models, to decipher mechanisms, that drove the development of new medicines. Discoveries are listed that either changed women's health or allowed an understanding of originally opaque mechanisms of action of potential therapies. These advances in women's health were supported entirely by government-sponsored peer-reviewed funding and major philanthropy from the Lynn Sage Breast Cancer Foundation, the Avon Foundation, and the Susan G. Komen Breast Cancer Foundation. The resulting lives saved or extended, families aided in a time of crisis and the injection of billions of dollars into national economies by drug development, is proof of the value of Federal or philanthropic investment into unencumbered research aimed at saving millions of lives., (© 2021. The Author(s).)

Objectives: In the United States, prostate cancer (PCa) is the most common cancer in men. Multi-parametric magnetic resonance imaging (MRI) is increasingly being relied upon for the diagnosis and characterization of PCa, but differentiating malignancy from benign prostatic hyperplasia (BPH) in the transition zone using MRI can be challenging. The characteristically high levels of zinc in human prostate tissue and a close relationship between malignant proliferation and zinc homeostatic dysregulation create opportunities to visualize PCa with novel contrast media. In mouse models, glucose-stimulated zinc secretion (GSZS) can be preferentially observed in healthy prostate tissue compared with malignant tissue; in vivo, these differences can be captured with MRI by using Gdl1, a gadolinium-based zinc-responsive contrast agent. In this study, we examined whether this technology can be applied in a large animal model by imaging older dogs with clinically diagnosed BPH., Materials and Methods: Four intact male dogs 6 years or older with enlarged prostates were imaged (T1-weighted turbo spin-echo, TE/TR, 12/400 milliseconds and T2-weighted, TE/TR, 112/5000 milliseconds) using a 3 T scanner before and at multiple time points after intravenous injection of 0.05 mmol/kg GdL1 plus either (a) 2 mL/kg of 50% dextrose in 1 session or (b) 2 mL/kg normal saline in another session. The two sessions were one week apart, and their order was randomly determined for each dog. During postprocessing, regions of interest were generated in prostate tissue and in paraspinal muscles to evaluate the contrast-to-noise ratio (CNR). The ratio of CNR at any postinjection time point compared with baseline CNR was defined as r-CNR. After the second imaging session, the dogs were euthanized, and their prostates were harvested for histopathological examination. Baseline and postintervention plasma and urine samples were analyzed for total zinc by inductively coupled plasma mass spectrometry., Results: The mean ± SD r-CNR values at 13 minutes postinjection in the dextrose versus saline imaging sessions were 134% ± 10% and 127% ± 7%, respectively (P < 0.01). The histopathologic evaluation of prostate tissues confirmed BPH in all dogs. Interestingly, prostatic intraepithelial neoplasia was detected in 1 animal, and a suspicious mass was found in the same region on T2-weighted scans. The r-CNR of the mass was calculated as 113% ± 4% and 111% ± 6% in the dextrose and saline groups, respectively, with no significant differences between the 2 interventions (P = 0.54), whereas there was a statistically significant difference between the r-CNR of the whole prostate in the dextrose (130% ±11%) and saline (125% ± 9%) interventions (P = 0.03). Inductively coupled plasma mass spectrometry analyses showed a significantly higher urinary zinc in the dextrose versus saline groups, but no differences were found in plasma zinc levels., Conclusions: T1-weighted MRI of the enlarged canine prostate showed higher r-CNR after injection of GdL1 plus dextrose compared with GdL1 plus saline, consistent with GSZS from BPH tissues. One small region of neoplastic tissue was identified in a single dog on the basis of less GSZS from that region by MRI. These findings suggest a new method for the detection of PCa by MRI that could facilitate the differentiation of BPH from PCa in the transition zone., Competing Interests: Conflicts of interest and sources of funding: Funding source has been disclosed in the submission. This work was supported by a research grant from the Cancer Prevention and Research Institute of Texas (RP180178)., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

A Mn(II)-based zinc-sensitive MRI contrast agent, MnPyC3A-BPEN, was prepared, characterized, and applied in imaging experiments to detect glucose-stimulated zinc secretion (GSZS) from the mouse pancreas and prostate in vivo . Thermodynamic and kinetic stability tests showed that MnPyC3A-BPEN has superior kinetic inertness compared to GdDTPA, is less susceptible to transmetalation in the presence of excess Zn 2+ ions, and less susceptible to transchelation by albumin. In comparison with other gadolinium-based zinc sensors bearing a single zinc binding moiety, MnPyC3A-BPEN appears to be a reliable alternative for imaging β-cell function in the pancreas and glucose-stimulated zinc secretion from the prostate.

Patients with long-term estrogen-deprived breast cancer, after resistance to tamoxifen or aromatase inhibitors develops, can experience tumor regression when treated with estrogens. Estrogen's antitumor effect is attributed to apoptosis via the estrogen receptor (ER). Estrogen treatment can have unpleasant gynecologic and nongynecologic adverse events; thus, the development of safer estrogenic agents remains a clinical priority. Here, we study synthetic selective estrogen mimics (SEM) BMI-135 and TTC-352, and the naturally occurring estrogen estetrol (E 4 ), which are proposed as safer estrogenic agents compared with 17β-estradiol (E 2 ), for the treatment of endocrine-resistant breast cancer. TTC-352 and E 4 are being evaluated in breast cancer clinical trials. Cell viability assays, real-time PCR, immunoblotting, ERE DNA pulldowns, mass spectrometry, X-ray crystallography, docking and molecular dynamic simulations, live cell imaging, and Annexin V staining were conducted in 11 biologically different breast cancer models. Results were compared with the potent full agonist E 2 , less potent full agonist E 4 , the benchmark partial agonist triphenylethylene bisphenol (BPTPE), and antagonists 4-hydroxytamoxifen and endoxifen. We report ERα's regulation and coregulators' binding profiles with SEMs and E 4 We describe TTC-352's pharmacology as a weak full agonist and antitumor molecular mechanisms. This study highlights TTC-352's benzothiophene scaffold that yields an H-bond with Glu353, which allows Asp351-to-helix 12 (H12) interaction, sealing ERα's ligand-binding domain, recruiting E 2 -enriched coactivators, and triggering rapid ERα-induced unfolded protein response (UPR) and apoptosis, as the basis of its anticancer properties. BPTPE's phenolic OH yields an H-Bond with Thr347, which disrupts Asp351-to-H12 interaction, delaying UPR and apoptosis and increasing clonal evolution risk., (©2020 American Association for Cancer Research.)

Following the discovery and approval of the oral contraceptive, the pharmaceutical industry sought new opportunities for the regulation of reproduction. The discovery of the first non-steroidal anti-oestrogen MER25, with antifertility properties in laboratory animals, started a search for 'morning-after pills'. There were multiple options in the 1960s, however, one compound ICI 46,474 was investigated, but found to induce ovulation in subfertile women. A second option was to treat stage IV breast cancer. Although the patent for ICI 46,474 was awarded in the early 1960s in the UK and around the world, a patent in the USA was denied on the basis that the claims for breast cancer treatment were not supported by evidence. A trial at the Christie Hospital and Holt Radium Institute in Manchester, published in 1971, showed activity compared with alternatives: high-dose oestrogen or androgen treatment, but the US Patent Office was unswayed until 1985! The future of tamoxifen to be, was in the balance in 1972 but the project went forward as an orphan drug looking for applications and a translational research strategy was needed. Today, tamoxifen is known as the first targeted therapy in cancer with successful applications to treat all stages of breast cancer, male breast cancer, and the first medicine for the reduction of breast cancer incidence in high-risk pre- and post-menopausal women. This is the unlikely story of how an orphan medicine changed medical practice around the world, with millions of women's lives extended.