Estrogen Response Research Articles

Lead Compound Development of SRC-3 Inhibitors with Improved Pharmacokinetic Properties and Anticancer Efficacy.

Steroid receptor coactivator 3 (SRC-3) is a critical mediator of many intracellular signaling pathways that are crucial for cancer proliferation and metastasis. In this study, we performed structure-activity relationship exploration and drug-like optimization of the hit compound SI-2, guided by in vitro/in vivo metabolism studies and cytotoxicity assays. Our efforts led to the discovery of two lead compounds, SI-10 and SI-12. Both compounds exhibit potent cytotoxicity against a panel of human cancer cell lines and demonstrate acceptable pharmacokinetic properties. A biotinylated estrogen response element pull-down assay demonstrated that SI-12 could disrupt the recruitment of SRC-3 and p300 in the estrogen receptor complex. Importantly, SI-10 and SI-12 significantly inhibited tumor growth and metastasis in vivo without appreciable acute toxicity. These results demonstrate the potential of SI-10 and SI-12 as drug candidates for cancer therapy, given their potent SRC-3 inhibition and promising pharmacokinetic and toxicity profiles.

Abstract 4207: Zoledronic acid reduces quiescent bone-disseminated human ER+ breast cancer tumor cell burden and estrogen-responsiveness in a pre-clinical model

Abstract Unique to early-stage ER+ breast cancer, ER+ tumor cells already bone disseminated at time of diagnosis can remain dormant at this site until an initiating event (e.g., activating ESR1 mutation acquisition) allows for osteolytic bone metastases (BMET) progression even decades later. Adjuvant use of anti-resorptive bisphosphonates, but not denosumab, reduces BMET risk in post-menopausal women with early stage breast cancer, suggesting protective effects may be unrelated to changes in bone turnover. Pre-clinical modeling of dormant, bone-disseminated ER+ breast cancer cells may enhance our understanding and thus our ability to better target these inherently treatment-resistant cells. In studies reported here, a model of bone-disseminated ER+ dormancy was characterized and used to query effects of zoledronic acid (ZA) on dormant cells. When female nude mice were inoculated (intracardiac) with human ER+ MCF-7 cells labelled with DiD, a membrane dye that dissipates with each cell division, DiD-positive tumor cell number in harvested tibial bone marrow remained unchanged from 24 hours to 28 days post-tumor cell inoculation. When 17ß-estradiol (E2) treatment (0.72 mg 60-day pellets) was initiated on D28 following tumor cell inoculation, detectable DiD+ tumor cell number in harvested tibial bone marrow increased 1.8-fold within one week (D35 vs. D28, p < 0.0001), consistent with initiation of E2-stimulated proliferation, and osteolytic, histology-confirmed BMET appeared subsequently with 60% incidence by 6-weeks post-start of E2 treatment. When mice were instead zoledronic acid-treated during the 28d dormancy period (70 ug/kg subcutaneously on D7 and on D21 post-inoculation), DiD-positive cell number in marrow harvested on D28 was reduced by more than half vs. vehicle-treated controls (p< 0.05). Moreover, DiD-positive cell numbers on D35, one week after start of E2-treatment, remained unchanged in tibial marrow of ZA-treated mice and were thus substantially (3.8-fold) lower than controls (p< 0.001). When followed for 6-weeks after initiation of E2 treatment, no osteolytic BMET were detected in ZA-treated mice. In toto, these results recapitulate clinical findings, thus validating the methodologic approach, and suggest that in addition to reducing dormant ER+ tumor cell burden in bone, bisphosphonates may also alter their estrogen responsiveness. Acknowledgements: Special thanks to undergraduates Alyssa Magee and Geethika Ameneni for assistance with data acquisition, and the METAvivor Foundation and NIH-NCI (NCI R03 CA181893, R01 CA174926, P30 CA023074, T32 CA009213) for financial support. Citation Format: Julia N. Cheng, Jennifer B. Frye, Susan A. Whitman, Janet L. Funk. Zoledronic acid reduces quiescent bone-disseminated human ER+ breast cancer tumor cell burden and estrogen-responsiveness in a pre-clinical model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4207.

Abstract 2168: Intermittent fasting in combination with carboplatin in a pre-clinical model of obesity-driven endometrial cancer

Abstract Objectives: Endometrial cancer (EC) incidence and mortality continue to rise, with obesity a well-known driver of this disease. Obesity is associated with excess estrogen, hyperinsulinemia, activation of the Akt/mTOR pathway, chronic inflammation, and a heightened capacity to harvest dietary energy, all of which contribute to the development and progression of EC. Intermittent energy restriction (IER) is thought to have anti-tumorigenic benefits and has been shown to have synergistic effects with chemotherapy and hormonal therapy in various cancer types. Thus, we evaluated the anti-tumorigenic effects of a switch from high fat diet (HFD) to either IER or low fat diet (LFD) with carboplatin treatment in a mouse model of obesity-driven endometrioid EC. Methods: Lkb1fl/flp53fl/fl mice were fed either HFD or LFD starting at 4 weeks of age. At 12 weeks of age, the HFD-fed mice were randomized to three treatment groups: continuous HFD, HFD-LFD switch, and HFD-IER switch. The LFD-fed mice were continuously maintained on LFD. At 16 weeks of age, all mice were injected with AdCre into the left uterine horn to induce EC development. At 26 weeks of age, mice were treated with placebo or carboplatin (50 mg/kg intraperitoneally weekly) for 4 weeks (n=8-10 mice per group). EC incidence, tumor weight, and body weight were evaluated. EC gene expression was assessed by microarray analysis. Results: EC incidence was lowest in the HFD-IER group (~60%) and highest in the HFD group (~80%); rates were similar in the other diet groups (~75%). The continuous HFD-fed mice demonstrated a 76% increase in tumor size relative to continuous LFD-fed mice (p<0.001). At sacrifice and after carboplatin treatment, mean body weights were significantly higher (p<0.05) in the HFD group (38g) than groups receiving continuous LFD (26g), HFD-LFD switch (28g), or HFD-IER switch (21g), although mean body weights were not significantly different within diet groups between placebo and carboplatin-treated mice. In placebo-treated groups, mean tumor weights were significantly lower in mice fed continuous LFD (0.62g), HFD-LFD switch (0.60g) and HFD-IER switch (0.26g) relative to continuous HFD-fed mice (1.10 g; p<0.001). When comparing gene expression between the HFD-LFD and the HFD-IER placebo groups, genes related to cholesterol metabolism, estrogen response, and inflammation were preferentially up-regulated in the HFD-IER group. Carboplatin treatment reduced EC tumor size 42-69% across all diet groups (p<0.05); tumor size was the smallest in the HFD-IER group (0.15g) relative to mice receiving continuous HFD (0.34g), HFD-LFD (0.29g) or continuous LFD (0.34g). Conclusion: IER with carboplatin treatment may be an innovative combination treatment strategy in the management of EC, a highly obesity-driven cancer. Citation Format: Jennifer Haag, Olivia Lara, Chunxiao Zhou, Stephen D. Hursting, Victoria Bae-Jump. Intermittent fasting in combination with carboplatin in a pre-clinical model of obesity-driven endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2168.

Single-cell analysis reveals landscape of endometrial cancer response to estrogen and identification of early diagnostic markers.

The development of endometrial cancer (EC) is closely related to the abnormal activation of the estrogen signaling pathway. Effective diagnostic markers are important for the early detection and treatment of EC. We downloaded single-cell RNA sequencing (scRNA-seq) and spatial transcriptome (ST) data of EC from public databases. Enrichment scores were calculated for EC cell subpopulations using the "AddModuleScore" function and the AUCell package, respectively. Six predictive models were constructed, including logistic regression (LR), Gaussian naive Bayes (GaussianNB), k-nearest neighbor (KNN), support vector machine (SVM), extreme gradient boosting (XGB), and neural network (NK). Subsequently, receiver-operating characteristics with areas under the curves (AUCs) were used to assess the robustness of the predictive model. We classified EC cell coaggregation into six cell clusters, of which the epithelial, fibroblast and endothelial cell clusters had higher estrogen signaling pathway activity. We founded the epithelial cell subtype Epi cluster1, the fibroblast cell subtype Fib cluster3, and the endothelial cell subtype Endo cluster3 all showed early activation levels of estrogen response. Based on EC cell subtypes, estrogen-responsive early genes, and genes encoding Stage I and para-cancer differentially expressed proteins in EC patients, a total of 24 early diagnostic markers were identified. The AUCs values of all six classifiers were higher than 0.95, which indicates that the early diagnostic markers we screened have superior robustness across different classification algorithms. Our study elucidates the potential biological mechanism of EC response to estrogen at single-cell resolution, which provides a new direction for early diagnosis of EC.

Abstract 5480: Single cell and spatial transcriptomic profile of appendiceal tumour peritoneal disease

Abstract Introduction: Appendiceal tumors (AT) are rare and often develop peritoneal disease (PD), with 5 year survival of 15-63% for high grade adenocarcinomas (HG) and 46-96% for low grade mucinous neoplasms (LG). While the mainstay of treatment is cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC), the role of systemic chemotherapy is less clear with limited biological characterization of AT and its tumor microenvironment (TME). The purpose of this study was to evaluate the TME of AT PD. Here we present an atlas of AT PD cells alongside a spatially resolved transcriptomic profile comparing HG and LG. Methods: We collected tissue from 29 patients with AT PD during CRS prior to HIPEC (18 LG, nine HG and two no tumor control). We performed comprehensive single-cell RNA sequencing (38224 cells) on fresh tissue specimens from nine patients (four HG, five LG), and whole transcriptome spatial analysis (>18000 genes) using the GeoMx Digital Spatial Profiler on formalin-fixed paraffin-embedded tissue from 22 patients (five HG, 13 LG). In the spatial profiling, we used anti-CK20, anti-CD45 and SYTO 83 as morphology markers to select areas of interest (AOIs): tumor (CK20), immune (CD45) and stroma (non-CK20/CD45). Analyses were performed with R and a false discovery rate threshold of 0.05. Results: Single-cell RNA sequencing showed that both LG and HG have a preponderance of T-lineage cells including CD8, CD4 and NK T-cells. Both LG and HG tumors display association of mesothelial cells with cancer-associated fibroblasts (CAF), and CAF subsets expressing genes of epithelial-mesenchymal transition (EMT). LG and HG tumors display different patterns of mucin gene expression - epithelial cells of HG express the secreted mucin MUC20 in addition to MUC2 and MUC5B also expressed in LG; a subset of mesothelial cells in LG but not HG express the transmembrane mucin genes MUC1, MUC3A, MUC12 and MUC16. Spatial analysis of tumor AOIs revealed HG compared to LG had increased expression of genes associated with MYC targets, oxidative phosphorylation, anti-tumor immune pathways (IFNα/γ response, intestinal immune network for IGA production), cell cycle pathways (E2F targets, G2M checkpoint) and EMT. LG compared to HG had increased expression of genes associated with inflammation-mediated disease (TNFα signaling via NFKB, inflammatory response), regulation of tumor growth (P53), hypoxia and early cell cycle (estrogen response) and glycosylation pathways. Immune and stromal AOIs did not have significant transcriptomic differences between LG and HG. Conclusion: This study provides novel insights into the biological profile of AT PD by describing TME cell types, immune function, tumor growth and cell cycle pathways. These findings may be used to identify clinically relevant biomarkers and new therapeutic targets. Citation Format: Madeleine C. Strach, Nicole Yeung, Eva Apostolov, Tony Wang, Hui-Ming Lin, Nabila Ansari, Cherry Koh, Joo-Shik Shin, James Kench, Alexander Swarbrick, Lisa Horvath, Kate L. Mahon. Single cell and spatial transcriptomic profile of appendiceal tumour peritoneal disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5480.

Abstract 6253: Single-cell RNA sequencing reveals metastatic site-specific biomarkers for predicting response to CDK4/6 inhibition in advanced HR+/HER2- breast cancer

Abstract Background: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), in combination with endocrine therapy, are established as standard treatment for advanced HR+/HER2- breast cancer (BC). However, response heterogeneity is observed, with approximately one-third of patients exhibiting intrinsic resistance. This study investigates the mechanisms of variable responses to CDK4/6i through single-cell RNA sequencing of metastatic site biopsies, revealing distinct biomarkers for predicting CDK4/6i response. Methods: Single-cell RNA sequencing analyzed metastatic tumors from advanced HR+/HER2- BC patients pre-CDK4/6i treatment at baseline (BL) and/or at disease progression. BL samples were from CDK4/6i responders (n = 8, median progression-free survival [mPFS] = 17 months), while progressors were categorized as early-progressors (EP, n = 3, mPFS = 3 months) and late-progressors (LP, n = 8, mPFS = 10 months). Metastatic sites included liver (10), pleural effusions (6), ascites (2), and bone (1). InferCNV distinguished tumor cells, and functional analysis utilized the Molecular Signatures Database. Results: Both EP and LP tumor cells exhibited reduced estrogen response and increased IFN-γ pathways compared to BL tumors. LP tumors displayed enhanced Myc targets, EMT, TNF-α, and inflammatory pathways compared to EP tumors, revealing differential mechanisms of early versus late progression. Predictive signatures, including TFF3 and MGP, were significantly upregulated in BL tumor cells across different metastatic sites. Metastasis-specific markers included APOA and SERPINA1 (liver), and AGR2 (pleural effusion). BL and LP responders showed increased tumor infiltrating CD8+ T cell and NK cells compared to EP non-responders. Notably, despite a high CD8+ T frequency in responder tumors, functional analysis revealed a significant upregulation of genes associated with stress/apoptosis and exhaustion in proliferative CD4+ and CD8+ T cells from BL compared to LP tumors, including HSP90 and HSPA8, associated with poor response to immune checkpoint inhibitors. These findings suggest potential benefits of immunotherapy for CDK4/6i late progressors. Longitudinal biopsies further revealed dynamic NK cell expansion and enhanced cytotoxic T cell activity alongside the downregulation of stress/apoptosis gene expression at progression compared to BL tumors. Conclusion: This study underscores the significance of metastatic site-specific biomarkers in predicting outcomes to CDK4/6i. Tumor-infiltration lymphocytes may also serve as baseline predictors, while stress/apoptosis gene signatures suggest checkpoint inhibitor usage in CDK4/6i late progressors. These potentially actionable findings emphasize the need to optimize therapeutic approaches based on microenvironment-specific changes following disease progression. Citation Format: Linjie Luo, Peng Yang, Sofia Mastoraki, Yan Wang, Nicole M. Kettner, Akshara Singareeka Raghavendra, Debasish Tripathy, Senthil Damodaran, Kelly K. Hunt, Ziyi Li, Khandan Keyomarsi. Single-cell RNA sequencing reveals metastatic site-specific biomarkers for predicting response to CDK4/6 inhibition in advanced HR+/HER2- breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6253.

Rational evolution for altering the ligand preference of estrogen receptor alpha.

Estrogen receptor α is commonly used in synthetic biology to control the activity of genome editing tools. The activating ligands, estrogens, however, interfere with various cellular processes, thereby limiting the applicability of this receptor. Altering its ligand preference to chemicals of choice solves this hurdle but requires adaptation of unspecified ligand-interacting residues. Here, we provide a solution by combining rational protein design with multi-site-directed mutagenesis and directed evolution of stably integrated variants in Saccharomyces cerevisiae. This method yielded an estrogen receptor variant, named TERRA, that lost its estrogen responsiveness and became activated by tamoxifen, an anti-estrogenic drug used for breast cancer treatment. This tamoxifen preference of TERRA was maintained in mammalian cells and mice, even when fused to Cre recombinase, expanding the mammalian synthetic biology toolbox. Not only is our platform transferable to engineer ligand preference of any steroid receptor, it can also profile drug-resistance landscapes for steroid receptor-targeted therapies.

Integrated transcriptome sequencing and weighted gene co-expression network analysis reveals key genes of papillary thyroid carcinomas

ObjectivePapillary thyroid carcinoma (PTC) accounts for the majority of thyroid cancers and has a high recurrence rate. We aimed to screen key genes involved in PTC to provide novel insights into the mechanisms of PTC. MethodsSeven microarray datasets of PTC were downloaded from gene expression omnibus database. Differentially expressed genes (DEGs) between PTC and normal samples were screened in the merged dataset. Then, protein-protein interaction (PPIs) functional modules analysis and weighted gene co-expression network analysis (WGCNA) were utilized to identify PTC-associated key genes. The identified key genes were then characterized from various aspects, including gene set enrichment analysis (GSEA) and the associations with immune infiltration, methylation levels and prognosis. ResultsA large numbers of DEGs were identified, and these DEGs are involved in several cancer pathways. Nine key genes (including down-regulated genes GNA14, AVPR1A, and WFS1, and up-regulated genes LAMB3, PLAU, MET, MFGE8, PRSS23, and SERPINA1) were identified. Patients in the AVPR1A and GNA14 high expression groups had better disease-free survival (DFS) than those in the low expression group. Key genes were mainly involved in P53 pathway, estrogen response, apoptosis, glycolysis, NOTCH signaling, epithelial mesenchymal transition, WNT_beta catenin signaling, and inflammatory response. The expression of key genes was associated with immune cell infiltration and corresponding methylation levels. The verification results of key gene proteins and mRNA expression levels using external validation datasets were consistent with our expectations, implying the involvements of key genes in PTC. ConclusionThe key genes may serve as potential therapeutic targets for PTC. This study provides novel insights into the mechanisms underlying PTC development.

Identification of estrogen response-associated STRA6+ granulosa cells within high-grade serous ovarian carcinoma by single-cell sequencing

BackgroundHigh-grade serous ovarian carcinoma (HGSOC) is a pathologic subtype of ovarian cancer (OC) with a more lethal prognosis. Extensive heterogeneity results in HGSOC being more susceptible to treatment resistance and adverse treatment effects. Revealing the heterogeneity involved is crucial. MethodsWe downloaded the single-cell RNA-seq (scRNA) data from GEO database and performed a scRNA analysis for cell landscape of HGSOC by using the Seurat package. The highly expressed genes were uploaded into the DAVID and KEGG database for enrichment analysis, and the AUCell package was used to calculate cancer-associated hallmark score. The SCENIC analysis was used for key regulons, the estrogen response enrichment scores in TCGA-OV RNA-seq dataset were calculated by using the GSVA package. Besides, the expression of STRA6 and IRF1 and the cell invasion and migration in si-STRA6 OC cells were detected by using the quantitative reverse transcription (qRT)-PCR method and Transwell assay respectively. ResultsWe successfully constructed a single-cell atlas of HGSOC and delineated the heterogeneity of epithelial cells therein. There were five epithelial cell subpopulations, GLDC + Epithelial cells, PEG3+ leydig cells, STRA6+ granulosa cells, POLE2+ Epithelial cells, and AURKA + Epithelial cells. STRA6+ granulosa cells have the potential to promote tumor growth as well as the highest estrogen response early activity through the biological pathways analysis of highly expressed genes and estrogen response score of ssGSEA. We found that IRF1 and STRA6 expression was remarkably upregulated in the OC cancer cell line HEY. Silencing of STRA6 markedly decreased the invasion and migration ability of the OC cancer cell line HEY. ConclusionThere is extreme heterogeneity of epithelial cells in HGSOC, and STRA6+ granulosa cells may be able to promote cancer progression. Our findings are benefit to the heterogeneity identification of HGSOC and develop targeted therapy strategy for HGSOC patients.

APOE genotype-specific methylation patterns are linked to Alzheimer disease pathology and estrogen response

The joint effects of APOE genotype and DNA methylation on Alzheimer disease (AD) risk is relatively unknown. We conducted genome-wide methylation analyses using 2,021 samples in blood (91 AD cases, 329 mild cognitive impairment, 1,391 controls) and 697 samples in brain (417 AD cases, 280 controls). We identified differentially methylated levels in AD compared to controls in an APOE genotype-specific manner at 25 cytosine-phosphate-guanine (CpG) sites in brain and 36 CpG sites in blood. Additionally, we identified seven CpG sites in the APOE region containing TOMM40, APOE, and APOC1 genes with P < 5 × 10−8 between APOE ε4 carriers and non-carriers in brain or blood. In brain, the most significant CpG site hypomethylated in ε4 carriers compared to non-carriers was from the TOMM40 in the total sample, while most of the evidence was derived from AD cases. However, the CpG site was not significantly modulating expression of these three genes in brain. Three CpG sites from the APOE were hypermethylated in APOE ε4 carriers in brain or blood compared in ε4 non-carriers and nominally significant with APOE expression in brain. Three CpG sites from the APOC1 were hypermethylated in blood, which one of the 3 CpG sites significantly lowered APOC1 expression in blood using all subjects or ε4 non-carriers. Co-methylation network analysis in blood and brain detected eight methylation networks associated with AD and APOE ε4 status. Five of the eight networks included genes containing network CpGs that were significantly enriched for estradiol perturbation, where four of the five networks were enriched for the estrogen response pathway. Our findings provide further evidence of the role of APOE genotype on methylation levels associated with AD, especially linked to estrogen response pathway.

Phloretin Inhibits the Proliferation of Breast Cancer Cells Through the Down-regulation of Estrogen Receptor α.

Phloretin is a natural flavonoid compound found in some plants, such as apples and pears, as well as in the bark of apple trees. Phloretin has been shown to have inhibitory effects on glucose transporters in cells and can potentially inhibit the growth of cancer cells. However, the mechanism by which phloretin regulates the expression of estrogen receptor alpha (ERα), a key transcription factor in breast cancer, is still unclear. This study investigated how phloretin affects the growth of ERα positive human breast cancer cells. The growth of breast cancer cell lines, including MCF7 and T47D, was examined using cell proliferation and colony formation assays. Western blotting and semi-quantitative RT-PCR were used to examine protein and mRNA levels, respectively. Localization of cellular proteins was analyzed using subcellular fractionation. Transient transfection and reported gene assays were used to elucidate the impact of phloretin on cell proliferation and ERα transactivation. Phloretin decreased ERα expression at the mRNA and protein levels in MCF7 and T47D cells. It also inhibited the binding of ERα to the estrogen response element present in the promoter of target genes. Moreover, treatment with phloretin inhibited the expression of cyclin D1 and breast cancer marker gene pS2, which are known ERα target genes. Consequently, it inhibited the growth of ERα-positive human breast cancer cells. Furthermore, inhibition of breast cancer growth by phloretin was found to be mediated through both the ERα and ERK1/ERK2 pathways. Phloretin, a dihydrochalcone extracted from natural sources, exhibits the ability to regulate ERα function and suppress breast cancer cell proliferation.

In Silico Approach to Molecular Profiling of the Transition from Ovarian Epithelial Cells to Low-Grade Serous Ovarian Tumors for Targeted Therapeutic Insights.

This paper aims to elucidate the differentially coexpressed genes, their potential mechanisms, and possible drug targets in low-grade invasive serous ovarian carcinoma (LGSC) in terms of the biologic continuity of normal, borderline, and malignant LGSC. We performed a bioinformatics analysis, integrating datasets generated using the GPL570 platform from different studies from the GEO database to identify changes in this transition, gene expression, drug targets, and their relationships with tumor microenvironmental characteristics. In the transition from ovarian epithelial cells to the serous borderline, the FGFR3 gene in the "Estrogen Response Late" pathway, the ITGB2 gene in the "Cell Adhesion Molecule", the CD74 gene in the "Regulation of Cell Migration", and the IGF1 gene in the "Xenobiotic Metabolism" pathway were upregulated in the transition from borderline to LGSC. The ERBB4 gene in "Proteoglycan in Cancer", the AR gene in "Pathways in Cancer" and "Estrogen Response Early" pathways, were upregulated in the transition from ovarian epithelial cells to LGSC. In addition, SPP1 and ITGB2 genes were correlated with macrophage infiltration in the LGSC group. This research provides a valuable framework for the development of personalized therapeutic approaches in the context of LGSC, with the aim of improving patient outcomes and quality of life. Furthermore, the main goal of the current study is a preliminary study designed to generate in silico inferences, and it is also important to note that subsequent in vitro and in vivo studies will be necessary to confirm the results before considering these results as fully reliable.

Tumor circadian clock strength influences metastatic potential and predicts patient prognosis in luminal A breast cancer

Studies in shift workers and model organisms link circadian disruption to breast cancer. However, molecular circadian rhythms in noncancerous and cancerous human breast tissues and their clinical relevance are largely unknown. We reconstructed rhythms informatically, integrating locally collected, time-stamped biopsies with public datasets. For noncancerous breast tissue, inflammatory, epithelial-mesenchymal transition (EMT), and estrogen responsiveness pathways show circadian modulation. Among tumors, clock correlation analysis demonstrates subtype-specific changes in circadian organization. Luminal A organoids and informatic ordering of luminal A samples exhibit continued, albeit dampened and reprogrammed rhythms. However, CYCLOPS magnitude, a measure of global rhythm strength, varied widely among luminal A samples. Cycling of EMT pathway genes was markedly increased in high-magnitude luminal A tumors. Surprisingly, patients with high-magnitude tumors had reduced 5-y survival. Correspondingly, 3D luminal A cultures show reduced invasion following molecular clock disruption. This study links subtype-specific circadian disruption in breast cancer to EMT, metastatic potential, and prognosis.

Abstract A059: Heterogeneous cell populations in organoid models derived from breast preinvasive and invasive carcinomas after endocrine therapy

Abstract Approximately 80% of ductal carcinoma in situ (DCIS) and invasive breast cancers express hormone receptors (HR), and are typically treated with selective estrogen receptor modulators (SERMs) or aromatase inhibitors, or with additional HR-targeting agents in the research setting. However, the development of resistance poses a significant challenge. To better understand the mechanisms behind endocrine resistance and explore new treatment strategies, it is essential to have a reliable model system that accurately reflects the heterogeneous nature of breast lesions. In this study, we developed a protocol to generate patient-derived organoid cultures of pre-invasive and malignant breast lesions from patients with persistent or residual disease in the active surveillance or neoadjuvant setting after treatment with endocrine therapy. We generated n = 11 HR+ DCIS and n = 18 HR+ breast cancer organoids and used single-cell RNA-sequencing to characterize cell heterogeneity within individual organoid cultures. We observed mixed non-cancerous and malignant cells present within some cultures, and optimized protocols to minimize non-cancerous cell types. To better define endocrine sensitivity versus resistance, we also assessed responsiveness to estrogen and anti-estrogen therapy in individual cultures by monitoring organoid growth through live cell imaging and evaluating estrogen-response markers at the protein and RNA levels in response to treatment in vitro. Next, we applied our model system to evaluate endocrine resistance in heterogeneous tumor populations. We compared changes in cellular composition and signaling pathways in endocrine-resistant and endocrine-sensitive breast organoids based on in vitro metrics and/or correlation with clinical variables. In addition, within single cultures heterogeneous cell populations were identified with differential expression of ESR1 and HR target genes, generally falling into three cluster groups that could be defined based on different patterns of FOXA1, GATA3, TFF1, and XBP1 expression, among others. These populations also differed with evidence of co-expressed genes and signaling pathways related to breast tumorigenesis and differentiation (estrogen response, androgen response, mTOR signaling, metabolism) in putative HR-active cell populations in both pre-invasive and invasive breast cases. In summary, our study demonstrates that patient-derived breast and breast cancer organoids can be used to model estrogen responsiveness and endocrine resistance. We have established a platform that enables us to investigate the mechanisms underlying endocrine resistance at different premalignant and tumor stages to evaluate new treatment approaches. The ultimate goal of this work is to contribute to the development of new targeted therapies for endocrine-resistant breast lesions. Citation Format: Nadine Goldhammer, Shruti Warhadpande, Liana Beld, Cristian K. Maldonado Rodas, Allison Lam, Tam Binh Bui, Shoko Emily Abe, Michael Alvarado, Cheryl Ewing, Karen Goodwin, Rita Mukhtar, Jasmine Wong, Lamorna Brown Swigart, Gillian Hirst, Christopher Schwartz, Laura van't Veer, Laura Esserman, Jo Chien, Jennifer M. Rosenbluth. Heterogeneous cell populations in organoid models derived from breast preinvasive and invasive carcinomas after endocrine therapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A059.

Abstract B007: Vandetanib abrogates antiestrogen resistance in MAPK-driven ER+ breast cancer by halting key intracellular signaling pathways and multiple druggable kinases

Abstract Introduction: Vandetanib has been shown to abrogate ER+ breast cancer growth via inhibition of MAPK; we sought to elucidate the effects of Vandetanib on MAPK-driven endocrine-resistant breast cancer. Methods: Chronically treated MCF7-TAM (Tamoxifen), MCF7-EXE (Exemestane), and wild-type MCF7 ER+ breast cancer cell lines were treated with Vandetanib and/or Tamoxifen. Cell viability assays were conducted with CellTiter-Glo. Cells were treated with Vandetanib (10 uM) and vehicle for 24 hours, and mRNA sequencing was performed. To elicit TKI-specific proteomic changes, cells were treated with control or IC90 Vandetanib for 48 hours, and the signatures of kinase activity were determined using a multiplex inhibitor bead library coupled with mass spectrometry. Differential gene (DGE) and protein (DPE) expression analyses were performed to determine enriched and depleted transcripts and kinase activity with Vandetanib treatment. Gene set enrichment analysis was performed to determine the shared and unique pathways regulated by Vandetanib for each model. A Vandetanib response signature was compiled using the top 20 downregulated genes and analyzed with METABRIC and SCAN-B datasets to assess effects on survival in ER+ breast cancer patients. Results: MCF7-TAM and MCF7-EXE demonstrated lower Tamoxifen IC50 when treated with Vandetanib compared to Tamoxifen alone, which showed synergistic effects. Data analysis of mRNA libraries showed reduced tumor progression and signaling of MAPK, PI3K/AKT, RAS, CCND1, MYC, and EGFR across all three lines, as well as increased ERBB2 signaling, which may denote a potential adaptive bypass mechanism to Vandetanib treatment. Gene sets showed increased estrogen response, ESR1 activity, and sensitivity to tamoxifen across all three lines. Notable key players in PI3K/AKT and MAPK signaling such as TYRO3 were significantly downregulated at both the gene and protein levels. Additionally, JAK2 demonstrated dual upregulation and has been implicated with favorable prognosis due to associations with immune infiltration. The downregulated Vandetanib gene set conferred significantly improved OS (HR=0.75, p&amp;lt;0.0001, METABRIC; HR=0.87, p=0.034, SCAN-B) and RFS (HR=0.60, p&amp;lt;0.0001, METABRIC) in ER+ breast cancer patients from both datasets. Multiple druggable kinases such as RET, EGFR, FGFR2/3, CDK6, and SRC were depleted by Vandetanib treatment. Upregulated druggable kinases identified with Vandetanib treatment include MTOR, FGFR4, ERBB2, and JAK1. Conclusions: Vandetanib overcomes antiestrogen resistance in MAPK-driven models of ER+ breast cancer by halting key signaling pathways such as MAPK, PI3K/AKT, MYC, and ERBB2, among others. Upregulated druggable kinases may serve as targets to overcome resistance to Vandetanib. Downregulated targets with Vandetanib could serve as biomarkers to select patients most likely to benefit from Vandetanib treatment. Citation Format: Rasha T Kakati, Austin Whitman, Hyunsoo Kim, Philip M Spanheimer. Vandetanib abrogates antiestrogen resistance in MAPK-driven ER+ breast cancer by halting key intracellular signaling pathways and multiple druggable kinases [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr B007.

Revealing the Antiperspirant Components of Floating Wheat and Their Mechanisms of Action through Metabolomics and Network Pharmacology.

Floating wheat is a classical herbal with potential efficacy in the treatment of hyperhidrosis. Aiming at revealing the main components and potential mechanisms of floating wheat, a comprehensive and unique phytopharmacology profile study was carried out. First, common wheat was used as a control to look for chemical markers of floating wheat. In the screening analysis, a total of 180 shared compounds were characterized in common wheat and floating wheat, respectively. The results showed that floating wheat and common wheat contain similar types of compounds. In addition, in non-targeted metabolomic analysis, when taking the contents of the constituents into account, it was found that there indeed existed quite a difference between floating wheat and common wheat and 17 potential biomarkers for floating wheat. Meanwhile, a total of seven components targeted for hyperhidrosis were screened out based on network pharmacology. Seven key differential components were screened, among which kaempferol, asiatic acid, sclareol, enoxolone, and secoisolariciresinol had higher degree values than the others. The analysis of interacting genes revealed three key genes, namely, MAP2K1, ESR1, and ESR2. The Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses showed that various signaling pathways were involved. Prolactin signaling, thyroid cancer, endocrine resistance, gonadotropin secretion, and estrogen signaling pathways were the main pathways of the intervention of floating wheat in excessive sweating, which was associated with the estrogenic response, hormone receptor binding, androgen metabolism, apoptosis, cancer, and many other biological processes. Molecular docking showed that the screened key components could form good bindings with the target proteins through intermolecular forces. This study reveals the active ingredients and potential molecular mechanism of floating wheat in the treatment of hyperhidrosis and provides a reference for subsequent basic research.

ERβ-activated LINC01018 promotes endometriosis development by regulating the CDC25C/CDK1/CyclinB1 pathway

Endometriosis refers to as an estrogen-dependent disease. Estrogen receptor β (ERβ), the main estrogen receptor subtype which is encoded by the estrogen receptor 2 (ESR2) gene, can mediate the action of estrogen in endometriosis. Although selective estrogen receptor modulators can target the ERβ, they are not specific due to the wide distribution of ERβ. Recently, long noncoding RNAs have been implicated in endometriosis. Therefore, we aim to explore and validate the downstream regulatory mechanism of ERβ, and to investigate the potential role of long intergenic noncoding RNA 1018 (LINC01018) as a nonhormonal treatment for endometriosis. Our study demonstrates that the expression levels of ESR2 and LINC01018 are increased in ectopic endometrial tissues and reveals a significant positive correlation between the ESR2 and LINC01018 expression. Mechanistically, ERβ directly binds to an estrogen response element located in the LINC01018 promoter region and activates LINC01018 transcription. Functionally, ERβ can regulate the CDC25C/CDK1/CyclinB1 pathway and promote ectopic endometrial stromal cell proliferation via LINC01018 in vitro. Consistent with these findings, the knockdown of LINC01018 inhibits endometriotic lesion proliferation in vivo. In summary, our study demonstrates that the ERβ/LINC01018/CDC25C/CDK1/CyclinB1 signaling axis regulates endometriosis progression.

Prolactin-activated PAK1 potentiates estrogen response to breast cancer cell epithelial-mesenchymal transition, migration and invasion.

Hormones estrogen and prolactin exert independent effects on breast cancer while their crosstalk synergistically enhance breast cancer cell proliferation. We have previously shown that the serine/threonine kinase PAK1 is responsible for this effect and proposed the mechanism of PAK1 action. Here we extended our previous data to demonstrate that the PAK1 kinase is a common interplay in PRL and E2 crosstalk to regulate epithelial-mesenchymal transition, cell migration and invasiveness of human breast cancer cells.

GDF-15 levels in patients with polycystic ovary syndrome treated with metformin: a combined clinical and in silico pathway analysis.

Polycystic ovary syndrome (PCOS) is an endocrine disease characterized by metabolic, reproductive, and psychological manifestations. Growth and differentiation factor 15 (GDF-15) is a cytokine associated with metabolic and inflammatory disorders. Metformin is commonly used for the treatment of PCOS. We investigated the relationship between GDF-15 levels and PCOS, the effect of metformin on GDF-15 levels, and potential biologic pathways related to GDF-15. The study included 35 women with PCOS and 32 women without PCOS (controls). Both groups were compared in terms of GDF-15 levels. Additional analysis was conducted on samples from 22 women with PCOS who were treated with either metformin (n = 7) or placebo (n = 15), retrieved from a previous randomized, controlled trial. Levels of GDF-15 were measured using MILLIPLEX. The biologic pathways related to GDF-15 were evaluated using the databases STRING, SIGNOR, and Pathway Commons. The statistical analysis was conducted using the software SPSS. Levels of GDF-15 were higher in the PCOS group compared with the non-PCOS group (p = 0.039). Among women with PCOS, GDF-15 levels were higher in those treated with metformin compared with placebo (p = 0.007). The proteins related to GDF-15 overlapped between the databases, and a significant interaction was found between GDF-15 and proteins related to PCOS and its complications, including those related to estrogen response, oxidative stress, ovarian infertility, interleukin (IL)-18, IL-4, the ratio of advanced glycation end products to their receptor (AGE/RAGE), leptin, transforming growth factor beta (TGF-β), adipogenesis, and insulin. The findings of the present study suggest a relationship between GDF-15 and PCOS and a potential increase in GDF-15 levels with metformin treatment. An additional finding was that GDF-15 could be involved in biologic pathways related to PCOS complications.

Inducible transgene expression in CHO cells using an artificial transcriptional activator with estrogen-binding domain.

Biopharmaceuticals, including therapeutic antibodies, are rapidly growing products in the pharmaceutical market. Mammalian cells, such as Chinese hamster ovary (CHO) cells, are widely used as production hosts because recombinant antibodies require complex three-dimensional structures modified with sugar chains. Recombinant protein production using mammalian cells is generally performed with cell growth. In this study, we developed a technology that controls cell growth and recombinant protein production to induce recombinant protein production with predetermined timing. Expression of green fluorescent protein (GFP) gene and a single-chain antibody fused with the Fc-region of the human IgG1 (scFv-Fc) gene can be induced and mediated by the estrogen receptor-based artificial transcription factor Gal4-ERT2-VP16 and corresponding inducer drugs. We generated CHO cells using an artificial gene expression system. The addition of various concentrations of inducer drugs to the culture medium allowed control of proliferation and transgene expression of the engineered CHO cells. Use of 4-hydroxytamoxifen, an antagonist of estrogen, as an inducing agent yielded high gene expression at a concentration more than 10-fold lower than that of β-estradiol. When scFv-Fc was produced under inducing conditions, continuous production was possible for more than 2weeks while maintaining high specific productivity (57 pg cell-1 day-1 ). This artificial gene expression control system that utilizes the estrogen response of estrogen receptors can be an effective method for inducible production of biopharmaceuticals.