High Levels Of Androgen Receptor Research Articles

8743 Regulation Of Tryptophan 2,3-Dioxygenase 2 And Androgen Receptor In Triple-Negative Breast Cancer

Abstract Disclosure: L. Kuo: None. K. Lacey: None. N. Spoelstra: None. J.K. Richer: None. Background: Triple Negative Breast Cancer (TNBC) is an aggressive subtype with a peak recurrence rate within 3-5 years after initial diagnosis. Androgen receptor (AR) and Tryptophan 2,3-dioxygenase 2 (TDO2) are elevated in TNBC cells grown under anchorage-independent conditions and facilitate anoikis resistance. Several studies reported that the luminal AR subset of TNBC showed a positive enrichment of the tryptophan (TRP) catabolism pathway gene signature. Recent studies have demonstrated that aryl hydrocarbon receptor (AhR) inhibition decreases AR promoter transcriptional activity in prostate cancer. We have observed that TNBC with high AR have high levels of genes/proteins in the tryptophan catabolism pathway including the rate limiting enzyme TDO2. Hypothesis: TDO2 activity regulates AR expression through the downstream tryptophan catabolite kynurenine (KYN), which binds and activates AhR and AhR and AR may work together to promote TNBC progression. Methods: Human TNBC cell lines: MDA-MB-453, BT549, SUM159PT ​ were used in this study and the expression of TDO2 and AR were examined by immunohistochemistry (IHC) and western blot. TDO2 was stably knocked down (KD) via shRNA or overexpressed (OE) using lentivirus transduction. Mass spectrometry-based metabolomics were used to measure changes in TRP catabolite levels, and a cytokine array (R&D) was utilized to analyze conditioned media. Results: TDO2 and AR protein are positively correlated in human TNBC cell lines. Although overexpression of TDO2 did not alter AR protein expression in SUM159PT, in the human MDA-MB-453, which have high levels of AR, knockdown of TDO2 (shTDO2) reduced AR protein by 40% and production of kynurenine (KYN) was reduced by 50% (p<0.0001). This suggests that TDO2 activity, specifically KYN binding to AhR, may influence AR protein levels. Conditioned media (CM) from TDO2 OE and KD respectively increased and decreased CXCL5 and IGFBP2. Lastly, TCGA database analysis of TNBC tumors with high levels of both AhR and AR showed significantly shorter patient survival (HR=1.47, log rank p=0.046) compared to those with tumors with lower amounts of both genes. Conclusion: TDO2 and AR are positively correlated in human TNBC cell lines. Tumors with high levels of both AR and AhR result in significantly shorter survival time for TNBC patients. Knockdown of TDO2 significantly reduced KYN production and AR expression in luminal AR TNBC cell lines and future experiments will focus on the underlying mechanism behind this and whether it is dependent on KYN-mediated activation of AhR and if AhR stabilizes AR in TNBC. Presentation: 6/3/2024

8743 Regulation of Tryptophan 2,3-Dioxygenase 2 and Androgen Receptor in Triple-Negative Breast Cancer

Abstract Disclosure: L. Kuo: None. K. Lacey: None. N. Spoelstra: None. J.K. Richer: None. Background: Triple Negative Breast Cancer (TNBC) is an aggressive subtype with a peak recurrence rate within 3-5 years after initial diagnosis. Androgen receptor (AR) and Tryptophan 2,3-dioxygenase 2 (TDO2) are elevated in TNBC cells grown under anchorage-independent conditions and facilitate anoikis resistance. Several studies reported that the luminal AR subset of TNBC showed a positive enrichment of the tryptophan (TRP) catabolism pathway gene signature. Recent studies have demonstrated that aryl hydrocarbon receptor (AhR) inhibition decreases AR promoter transcriptional activity in prostate cancer. We have observed that TNBC with high AR have high levels of genes/proteins in the tryptophan catabolism pathway including the rate limiting enzyme TDO2. Hypothesis: TDO2 activity regulates AR expression through the downstream tryptophan catabolite kynurenine (KYN), which binds and activates AhR and AhR and AR may work together to promote TNBC progression. Methods: Human TNBC cell lines: MDA-MB-453, BT549, SUM159PT ​ were used in this study and the expression of TDO2 and AR were examined by immunohistochemistry (IHC) and western blot. TDO2 was stably knocked down (KD) via shRNA or overexpressed (OE) using lentivirus transduction. Mass spectrometry-based metabolomics were used to measure changes in TRP catabolite levels, and a cytokine array (R&D) was utilized to analyze conditioned media. Results: TDO2 and AR protein are positively correlated in human TNBC cell lines. Although overexpression of TDO2 did not alter AR protein expression in SUM159PT, in the human MDA-MB-453, which have high levels of AR, knockdown of TDO2 (shTDO2) reduced AR protein by 40% and production of kynurenine (KYN) was reduced by 50% (p<0.0001). This suggests that TDO2 activity, specifically KYN binding to AhR, may influence AR protein levels. Conditioned media (CM) from TDO2 OE and KD respectively increased and decreased CXCL5 and IGFBP2. Lastly, TCGA database analysis of TNBC tumors with high levels of both AhR and AR showed significantly shorter patient survival (HR=1.47, log rank p=0.046) compared to those with tumors with lower amounts of both genes. Conclusion: TDO2 and AR are positively correlated in human TNBC cell lines. Tumors with high levels of both AR and AhR result in significantly shorter survival time for TNBC patients. Knockdown of TDO2 significantly reduced KYN production and AR expression in luminal AR TNBC cell lines and future experiments will focus on the underlying mechanism behind this and whether it is dependent on KYN-mediated activation of AhR and if AhR stabilizes AR in TNBC. Presentation: 6/3/2024

Abstract 4102: Treatment with androgen receptor targeting vaccines provides an overall survival benefit in AR-V7 expressing tumor models

Abstract Background: Androgen receptor (AR) signaling inhibition is part of the mechanism behind many effective prostate cancer therapies, including androgen deprivation and next generation anti-androgens. However in castration resistant prostate cancer up to 50% of treatment resistance has been linked to AR amplification or expression of the constitutively active RNA splice variant, AR-V7. Although the use of immune checkpoint blockade has failed to demonstrate clinical success, immunotherapeutic interventions remain attractive as prostate cancer’s relatively slow progression provides time for anti-tumor immune responses to develop. Cancer specific vaccines have the potential to enable and enhance tumor specific immune responses by stimulating and directing T cell immunity to important oncologic targets. We hypothesized that a cancer vaccine designed to induce a T cell response against cells expressing high levels of AR would result in an anti-tumor effect and potentially prevent or delay the development of therapeutic resistance. Methods: Adenoviral vaccines against AR (Ad-AR) or AR splice variant 7 (Ad-AR-V7) were used to evaluate the potential of AR targeting vaccination in mouse models. We evaluated AR and AR variant specific adaptive responses produced by our vaccines with naïve and tumor-bearing mice by ex vivo peptide restimulation. We challenged vaccinated mice with multiple syngeneic subcutaneous tumor models that we engineered to express AR-V7, including a PTEN-/- p53-/- prostate tumor cell line. Finally we tested our vaccines in a therapeutic regimen, vaccinating mice after implanting our subcutaneous AR-V7 expressing models. Results: Across multiple strains of mice, AR or AR-V7 targeting adenoviral vaccination induced robust adaptive immune responses against the N-terminal domain of AR. Vaccination with either Ad-AR or Ad-AR-V7 resulted in significant anti-tumor responses, providing a significant overall survival benefit and complete tumor rejection by the majority of mice vaccinated against AR or AR-V7. Similarly tumor bearing mice treated with Ad-AR or Ad-AR-V7 vaccination displayed tumor growth inhibition or complete tumor regression resulting in an overall survival benefit. Additionally, we found that vaccine responses were unaffected by the use of the approved antiandrogen drug enzalutamide, suggesting that vaccinations could be deployed in tandem with standard-of-care therapies. Conclusions: Vaccination against AR and AR splice variants can induce AR specific adaptive immune responses capable of inhibiting the growth of AR-V7 expressing tumor models, illustrating the potential of AR and its splice variants as immunologic targets in prostate cancer. Citation Format: Robert D. Marek, Junping Wei, Tao Wang, Xiao-Yi Yang, Gangjun Lei, Zachary C. Hartman. Treatment with androgen receptor targeting vaccines provides an overall survival benefit in AR-V7 expressing tumor models [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 4102.

The use of transcriptomic data in developing biomarkers in breast cancer

AbstractHER2 and hormone receptors are biomarkers for selecting breast cancer therapy and predicting outcomes. In the era of antibody‐drug conjugates (ADC), a relatively low HER2 expression level is adequate for targeting tumor cells. We explored the potential of RNA profiling, determined by next generation sequencing (NGS), to provide more flexible clinical biomarkers as compared with immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH). Data from 57 breast cancers was used to study biomarker levels as detected by routine clinical transcriptomic tests. HER2 (ERBB2), estrogen receptor alpha (ESR1), and androgen receptor (AR) mRNA levels were compared with IHC and FISH results. There was a significant overlap in the levels of ERBB2 mRNA between cases scored by IHC as zero, 1+, and 2+. This variation correlated with progression‐free survival (PFS). Similarly, the ESR1 RNA accurately reflected estrogen receptor (ER) status. Patients with high AR mRNA had better PFS (p = 0.05). Patients expressing high ER and AR levels had better PFS than those expressing low ESR1 and AR (p = 0.03). These findings suggest that RNA analysis can be an alternative to IHC and FISH and provides continuous data that can better determine cut‐off points for predicting response to ADC.

Newly developed preclinical models reveal broad-spectrum CDK inhibitors as potent drugs for CRPC exhibiting primary resistance to enzalutamide.

Androgen-deprivation therapy is a standard treatment for advanced prostate cancer. However, most patients eventually acquire resistance and progress to castration-resistant prostate cancer (CRPC). In this study, we established new CRPC cell lines, AILNCaP14 and AILNCaP15, from LNCaP cells under androgen-deprived conditions. Unlike most pre-existing CRPC cell lines, both cell lines expressed higher levels of androgen receptor (AR) and prostate-specific antigen (PSA) than parental LNCaP cells. Moreover, these cells exhibited primary resistance to enzalutamide. Since AR signaling plays a significant role in the development of CRPC, PSA promoter sequences fused with GFP were introduced into AILNCaP14 cells to conduct GFP fluorescence-based chemical screening. We identified flavopiridol, a broad-spectrum CDK inhibitor, as a candidate drug that could repress AR transactivation of CRPC cells, presumably through the inhibition of phosphorylation of AR on the serine 81 residue (pARSer81 ). Importantly, this broad-spectrum CDK inhibitor inhibited the proliferation of AILNCaP14 cells both in vitro and in vivo. Moreover, a newly developed liver metastatic model using AILNCaP15 cells revealed that the compound attenuated tumor growth of CRPC harboring highly metastatic properties. Finally, we developed a patient-derived xenograft (PDX) model of CRPC and DCaP CR from a patient presenting therapeutic resistance to enzalutamide, abiraterone, and docetaxel. Flavopiridol successfully suppressed the tumor growth of CRPC in this PDX model. Since ARSer81 was found to be phosphorylated in clinical CRPC samples, our data suggested that broad-spectrum CDK inhibitors might be a potent candidate drug for the treatment of CRPC, including those exhibiting primary resistance to enzalutamide.

Targeting androgen receptor (AR) with a synthetic peptide increases apoptosis in triple negative breast cancer and AR-expressing prostate cancer cell lines.

The androgen receptor (AR) has been studied as an approach to cancer therapy. We used human breast cancer-derived cells with high, low, and very low expression levels of AR, in addition to prostate cancer-derived LNCaP and DU-145 cells as a positive and negative controls to examine apoptosis caused by a synthetic peptide that targets ARs. The peptide was produced to inhibit AR transactivation in breast cancer cell lines. We then measured cell viability, caspase-3 activity, and the ratio of Bax/Bcl-2. The findings indicated that the peptide (100-500 nM) in the presence of dihydrotestosterone (DHT) reduced cell growth in cells with high and low expression level of AR (p < .001), but not in cells with very low levels of AR. Treatment with 100-500 nM of peptide activated caspase-3 and increased the ratio of Bax/Bcl-2 in cells with high and low expression levels of AR. Also, increasing concentrations of the peptide (100-500 nM) reduced BrdU incorporation in the presence of DHT and promoted apoptosis in cells with high and low expression levels of AR (p < .001). The findings indicate the peptide significantly increased apoptosis in cancer cells.

Sex differences in ILC2 function in influenza result from imprinted donor sex intrinsic factors independent of host sex in competitive female-male bone marrow chimeras

Abstract Historical influenza pandemics and the SARS-CoV-2 pandemic revealed gender differences in morbidity of respiratory virus infections. In human or murine influenza A virus (IAV) infection, females of reproductive age generate stronger innate and adaptive antiviral responses leading to immunopathology, while elderly males often experience more severe disease. Sex hormone levels play a role in this disparity, yet little is known about cell intrinsic regulation of immune cells by estrogen or androgen receptors (AR). Lung resident type 2 innate lymphocytes (ILC2s) express high levels of AR, a nuclear hormone receptor that regulates chromatin via epigenetic modifications. While female lungs contain higher ILC2 numbers in homeostasis, we showed that ILC2s in females were preferentially functionally suppressed during IAV infection, whereas ILC2s in males retained robust type 2 function, including IL-5 production. Here, we determined if sex differences in pulmonary ILC2s result from extrinsic factors present in host environments or from imprinted donor-intrinsic factors. We set up competitive bone marrow chimeras by transferring a mix of female and male lineage-depleted bone marrow cells into either male or female hosts. Female hosts harbored more pulmonary ILC2s than male hosts, suggesting the extrinsic sex hormone environment regulates ILC2 numbers. Upon IAV infection, an increased fraction of ILC2s from male donors retained high IL33R expression and produced IL-5, regardless of host sex, suggesting donor sex-intrinsic factors regulate the canonical ILC2 functional response. We are now testing the hypothesis that androgens/AR activity epigenetically imprint genes regulating type 2 function in male ILC2s upon sexual maturity.

Abstract 967: Real-world transcriptomic biomarkers as replacement for immunohistochemistry and FISH studies in breast cancer

Abstract Background: Human epidermal growth factor receptor-2 (HER2) and hormone receptors are typically used as binary biomarkers for selecting breast cancer therapy. There is a need to explore the clinical relevance of these biomarkers as continuous variables. This is particularly relevant for the new class of antibody-drug conjugates (ADC), in which a relatively low HER2 expression level is adequate for targeting tumor cells. We explored the potential of RNA profiling, determined by next generation sequencing (NGS), to provide more flexible clinical biomarkers as compared with immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH). Methods: Clinical and laboratory data from 57 breast cancers collected by the COTA real-world data company were used to study biomarker levels as detected by routine clinical transcriptomic tests. HER2 (ERBB2), estrogen receptor alpha (ESR1), and androgen receptor (AR) mRNA levels were compared with reported HER2 and estrogen receptor (ER) IHC and FISH results. Results: RNA levels accurately reflected and predicted HER2 amplification (see table below). Importantly, RNA data showed significant variation and overlap in the levels of ERBB2 mRNA between cases scored by IHC as zero, 1+, and 2+. This variation correlated with progression-free survival (PFS). Similarly, the ESR1 RNA levels accurately reflected ER status and demonstrated significant variation between positive cases. RNA data also showed significant variations in the AR levels. Patients wssith high AR mRNA levels had significantly better PFS (P=0.05). Patients expressing high ER and AR levels had significantly better PFS than those expressing low ESR1 and AR levels (P=0.03). Conclusions: These findings suggest that RNA analysis using NGS is an alternative to IHC and FISH. RNA provides continuous data that can determine cut-off points predicting response to therapy and should be explored in predicting ADC response. ERBB2 mRNA levels (FPKM) in various HER2 IHC groupss IHC Score Valid N Mean Median Minimum Maximum Quartile Range Std.Dev. Zero 19 231 243 63 537 170 110 Zero vs one 3 151 155 45 253 208 104 Zero to one vs one 18 397 302 172 845 365 222 One Vs two 13 495 423 159 1094 273 284 Two vs three 4 7523 7649 937 13859 7183 5310 Citation Format: Maher Albitar, Andre Goy, Andrew Pecora, Deena Graham, Donna Donna McNamara, Ahmad Ahmad Charifa, Andrew IP, Wanlong Ma, Stanley Waintraub. Real-world transcriptomic biomarkers as replacement for immunohistochemistry and FISH studies in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 967.

Inceptor correlates with markers of prostate cancer progression and modulates insulin/IGF1 signaling and cancer cell migration

ObjectiveThe insulin/insulin-like growth factor 1 (IGF1) pathway is emerging as a crucial component of prostate cancer progression. Therefore, we investigated the role of the novel insulin/IGF1 signaling modulator inceptor in prostate cancer. MethodsWe analyzed the expression of inceptor in human samples of benign prostate epithelium and prostate cancer. Further, we performed signaling and functional assays using prostate cancer cell lines. ResultsWe found that inceptor was expressed in human benign and malignant prostate tissue and its expression positively correlated with various genes of interest, including genes involved in androgen signaling. In vitro, total levels of inceptor were increased upon androgen deprivation and correlated with high levels of androgen receptor in the nucleus. Inceptor overexpression was associated with increased cell migration, altered IGF1R trafficking and higher IGF1R activation. ConclusionsOur in vitro results showed that inceptor expression was associated with androgen status, increased migration, and IGF1R signaling. In human samples, inceptor expression was significantly correlated with markers of prostate cancer progression. Taken together, these data provide a basis for investigation of inceptor in the context of prostate cancer.

Abstract P4-08-01: Targeting CDK7 enhances the antitumor efficacy of enzalutamide in androgen receptor-positive triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. Among TNBC subtypes, the luminal androgen receptor (LAR) subtype expresses high levels of androgen receptor (AR), tends to be less proliferative, and generally responds poorly to neoadjuvant therapy. Previous studies have shown that AR inhibition suppressed proliferation of AR+ or LAR subtype TNBC cells and tumor growth in xenograft models. Thus, AR is a promising therapeutic target for this TNBC subtype. Here, we identified kinase targets for enhancing the antitumor efficacy of the AR inhibitor enzalutamide in preclinical models and investigated the underlying molecular mechanisms. Methods: We performed a nonbiased high-throughput kinome siRNA screening (targeting 709 genes) to identify a synergistic partner for enhancing the antitumor efficacy of the AR inhibitor enzalutamide in AR+ LAR TNBC. The growth inhibitory effects of enzalutamide alone or combined with kinase inhibitors were determined using the sulforhodamine B staining assay and clonogenic assay. The effect of treatments on the expression of target proteins of interest was examined by Western blot analysis. Results: Enzalutamide was not effective as a single agent to inhibit the proliferation of AR+ TNBC cells (IC50 &amp;gt;15 µM in MDA-MB-453, CAL-51, CAL-148, MFM223, HCC2185, SUM149, SUM159, and SUM185 cells). Nonbiased high-throughput kinome siRNA screening identified PI3K/AKT/mTOR, cell cycle, and JNK pathways as potential canonical targets for combination with enzalutamide to enhance its antitumor efficacy in AR+ LAR TNBC. Among these pathways, inhibition of cell cycle progression using the CDK7 inhibitor UD-017 showed the most synergistic anti-proliferation effect with enzalutamide in AR+ LAR MDA-MB-453 (50.61% reduction in proliferation compared with enzalutamide alone, P &amp;lt; 0.001; and 48.98% reduction in proliferation compared with UD-017 alone, P &amp;lt; 0.001) and SUM185 (40.41% reduction in proliferation compared with enzalutamide alone, P &amp;lt; 0.05; and 42.76% reduction in proliferation compared with UD-017 alone, P &amp;lt; 0.05) TNBC cells. Furthermore, CDK7 knockdown using siRNA significantly enhanced the sensitivity of MDA-MB-453 (60.98%, P &amp;lt; 0.01) and SUM185 (30.99%, P &amp;lt; 0.01) cells to enzalutamide, and AR knockdown significantly enhanced the sensitivity of MDA-MB-453 (32.64%, P &amp;lt; 0.01) and SUM185 (43.62%, P &amp;lt; 0.01) cells to UD-017, in both cases with a sensitivity similar to that of enzalutamide plus UD-017. This result suggests that the synergy of enzalutamide and UD-017 results from specific targeting of AR and CDK7. Downstream target analysis revealed that the combination of enzalutamide and UD-017 dramatically reduced the expression of c-MYC. c-MYC knockdown using siRNA dramatically suppressed colony formation in both MDA-MB-453 and SUM185 cells at a degree similar to that of enzalutamide plus UD-017, whereas c-MYC overexpression reversed the synergistic effect of the combination treatment. This result suggests that UD-017 synergizes with enzalutamide through inhibition of c-MYC–mediated tumorigenesis. Conclusion: Our results suggest that enzalutamide synergizes with UD-017 by inhibiting c-MYC–mediated oncogenic activity. These in vitro data warrant future in vivo studies of the antitumor synergy of enzalutamide plus UD-017 in AR+ LAR TNBC models. Citation Format: Xuemei Xie, Marwa Manai, Jon A. Fuson, Troy Pearson, Dileep R. Rampa, Debu Tripathy, Jangsoon Lee, Naoto T. Ueno. Targeting CDK7 enhances the antitumor efficacy of enzalutamide in androgen receptor-positive triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-01.

ODP441 NErbB-2 and Androgen Receptor Regulate a Gene Signature Involved in Immune Response and Favorable Outcome in TNBC

Abstract Triple negative breast cancer (TNBC) has poor prognosis and neither established biomarkers nor therapeutic targets. On the one hand, the androgen receptor (AR), a steroid hormone receptor (SR) which is expressed in 10-53% of TNBC and proved to be critical for BC proliferation, has been proposed as a new target in TNBC. On the other, we and others have shown that membrane ErbB-2 migrates to the nucleus (nuclear ErbB-2, NErbB-2) where it binds DNA at HER-2 associated sequences (HAS) to regulate BC proliferation and migration. Since we have previously shown a functional interplay between growth factors and SR signaling pathways in BC, we propose the existence of an interaction between AR and ErbB-2 which is involved in NErbB-2+/AR+ BC growth. The experimental model used was the human TNBC cell line MDA-MB-453 which displays high expression levels of AR and NErbB-2. We have previously shown that dihydrotestosterone (DHT)-activated AR induces Src-mediated ErbB-2 rapid activation and its migration to the nucleus where it binds to HAS sites in the DNA. By coimmunoprecipitation and WB studies, we have now shown that this crosstalk involves ErbB-2 and AR physical association which is inhibited by the AR antagonist enzalutamide. By microarray and bioinformatics analysis we have also previously identified a set of differentially expressed genes (DEGs) in the presence of DHT and NErbB-2 eviction to define an independent predictor of better clinical outcome in TNBC. By using the Tumor Immune Estimation Resource (TIMER) we found a significant association of the expression of the gene signature and the abundance of tumor immune infiltrates, in accordance with the involvement of the gene signature in the immune response and interferon pathways. We have validated the regulation of the gene signature in MDA-MB-453 cells and found that in the presence of DHT, eviction of NErbB-2 significantly induces the mRNA expression of the genes CXCL10, HLA-A, NMI, STAT1 and TAP1, members of said gene signature. We have also identified AREs and HAS sites in STAT1, NMI and TAP1 and studied AR and ErbB-2 recruitment to the chromatin by ChIP assays. We found that DHT induces ErbB-2 binding to its HAS sites in STAT1 in regulatory regions. Our findings evidence that DHT-activated AR induces ErbB-2 rapid activation and its migration to the nucleus where it binds to HAS sites in regulatory regions of a set of genes involved in the immune response in TNBC. Presentation: No date and time listed

Abstract 1029: The anti-androgen seviteronel sensitizes triple-negative breast cancer to chemotherapy

Abstract Therapeutic strategies that improve survival outcomes for advanced-stage breast cancers have proven a major clinical challenge. Here, we define an androgen receptor (AR) signalling network that governs the maintenance and de novo formation of cancer stem cells in triple-negative breast cancer. In response to chemotherapy, AR activation switches cells into a cancer stem cell state, while AR antagonism suppresses cancer stem cell formation and function. In vivo, we validate that the AR antagonist, seviteronel, significantly improves chemotherapy-mediated inhibition of primary and metastatic tumour growth. Analysing three independent triple-negative breast cancer patient cohorts we identify that cytoplasmic AR expression prognosticates poor survival in treatment-naïve patients and predicts poor response to chemotherapy. Additionally, Phase II clinical trial data demonstrates that seviteronel treatment followed by chemotherapy improved survival outcomes in triple-negative breast cancer patients expressing high cytoplasmic AR levels. Seviteronel combined with chemotherapy represents a promising therapeutic strategy for triple-negative breast cancer patients. Citation Format: Beatriz P. San Juan, Soroor Hediyah-Zadeh, Laura Rangel, Vanina Rodriguez, Heloisa H. Milioli, Felix Kohane, Carley A. Purcell, Therese E. Hickey, Leonard D. Goldstein, John G. Lock, Melissa J. Davis, Christine L. Chaffer. The anti-androgen seviteronel sensitizes triple-negative breast cancer to chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1029.

Transcriptome profiling and proteomic validation reveals targets of the androgen receptor signaling in the BT-474 breast cancer cell line

BackgroundAccumulating evidence suggests that the androgen receptor (AR) and its endogenous ligands influence disease progression in breast cancer (BCa). However, AR-mediated changes in BCa differ among the various BCa subtypes according to their hormone receptor profile [i.e., presence/absence of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2, (HER2)]. Thus, we explored the androgen-regulated transcriptomic changes in the ER+PR+HER2+ BCa cell line, BT-474, and compared them with PR-mediated changes.MethodsWe performed RNA sequencing analysis in treated BT-474 cells with dihydrotestosterone (DHT) and progesterone. Validation of the top ten differentially androgen-regulated genes and a number of other genes found in enriched signaling pathways was performed by qRT-PCR in BT-474 and other BCa cell lines. In addition, a parallel reaction monitoring targeted proteomic approach was developed to verify selected transcripts at the protein level.ResultsIn total 19,450 transcripts were detected, of which 224 were differentially regulated after DHT treatment. The increased expression of two well-known androgen-regulated genes, KLK2 (p < 0.05) and KLK3 (p < 0.001), confirmed the successful androgen stimulation in BT-474 cells. The transcription factor, ZBTB16, was the most highly upregulated gene, with ~ 1000-fold change (p < 0.001). Pathway enrichment analysis revealed downregulation of the DNA replication processes (p < 0.05) and upregulation of the androgen signaling and fatty acid metabolism pathways (p < 0.05). Changes related to progesterone treatment showed opposite effects in gene expression than DHT treatment. Similar expression profiles were observed among other BCa cell lines expressing high levels of AR (ZR75.1 and MBA-MB-453). The parallel reaction monitoring targeted proteomic analysis further confirmed that altered protein expression (KLK3, ALOX15B) in the supernatant and cell lysate of DHT-treated BT-474 cells, compared to control cells.DiscussionOur findings suggest that AR modulates the metabolism of BT-474 cells by affecting the expression of a large number of genes and proteins. Based on further pathway analysis, we suggest that androgen receptor acts as a tumor suppressor in the BT-474 cells.

Androgens protect ILC2s from interferon-mediated functional suppression during influenza virus infection

Abstract Biological sex differences in morbidity upon influenza A virus (IAV) infection are linked to stronger interferon-centered immune responses in females, yet the regulatory role of sex hormone receptors in immune cell subsets is incompletely understood. Lung-resident group 2 innate lymphoid cells (ILC2s) express notably high levels of androgen receptors (AR). In IAV infection, ILC2s produce type 2 cytokines and facilitate tissue repair, but they also may be functionally suppressed by type 1 inflammation. Here we report sex differences in the magnitude of lung ILC2 functional suppression at the peak of sublethal IAV infection. Relative to males, ILC2s in female lungs showed attenuated proliferation, decreased propensity for IL-5 and amphiregulin production and reduced expression of GATA3 and IL-33R. Single cell RNA sequencing revealed sex-divergent transcriptomes, with female cells preferentially present in clusters of stressed, functionally suppressed ILC2s and male cells dominating in clusters of canonically activated ILC2s. Equivalent inflammatory cytokine levels and viral load suggested sex differences in ILC2-intrinsic factors. Indeed, naïve female ILC2s showed elevated IFNGR expression and higher phospho-STAT1 levels following IFNG stimulation, and lymphocyte-restricted STAT1 deficiency reversed IAV-induced suppression of female ILC2s. Lymphocyte-restricted AR deficiency or loss of androgens via orchiectomy led to increased IFNGR expression and suppression of male ILC2s. Collectively, these data show that ILC2-intrinsic AR activity regulates IFNGR-STAT1 signaling pathways to preserve canonical ILC2 function in males during IAV infection. Supported by grants from NIH (HL 119501) and the Presbyterian Health Foundation

Androgens can modulate immunoregulation directly through gut cells and indirectly through alteration of microbiota composition/function in a lupus mouse model.

Abstract Hormones and gut microbiota affect lupus. In female NZBxNZW1(BWF1) mice, androgen treatment abrogates lupus; castration/treatment with androgen receptor blocker (flutamide) induces disease in BWF1 male mice. Gut microbiota alterations have been reported in lupus. Our goal is to understand the androgen/gut microbiota relationship, and its affect on lupus. We found male castration decreases peripheral, not thymic, derived Tregs; this correlates with decreased gut CD103 dendritic cells (CD103DC) function (induce Treg conversion) and RALDH2 [required for retinoic acid (RA) production) expression. CD103DC have very low androgen receptor (AR) expression, thus unlikely to be affected by androgens. We found that lamina propria stromal cells (LPSC), a major source of RA (via RALDH1/2 expression) required for normal gut CD103DC development, express very high AR levels. Castration/flutamide treatment in male mice decreased RALDH1/2 expression in LPSC, suggesting androgens may affect CD103DC function through LPSC. Castration/flutamide treatment also altered gut microbiota composition. Interestingly, intact male microbiota transfer to castrated male mice restored RALDH2 expression and CD103DC function, suggesting male microbiota factors may also alter CD103DC function. Metabolomic analysis of castrated male feces showed reduced phytanic acid (PA) levels. Administration of PA in vitro/in vivo restored castrated CD103DC function. These data strongly suggest that androgens alter (1) immunoregulatory function through gut cells and (2) gut microbiota composition/function that in turn modulate immunoregulatory function, and reveal how androgens may influence lupus and provide the basis for effective therapy development. Funded by a TIL grant from the Alliance for Lupus Research and the NIH (R01AR067188)

Androgen Receptor: A New Marker to Predict Pathological Complete Response in HER2-Positive Breast Cancer Patients Treated with Trastuzumab Plus Pertuzumab Neoadjuvant Therapy.

(1) Background: Neoadjuvant therapy is the main therapeutic strategy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients, and the combination of trastuzumab and pertuzumab (HP) has become a routine treatment. How to predict and screen patients who are less likely to respond to neoadjuvant therapy is the focus of research. The androgen receptor (AR) is a biomarker that is widely expressed in all breast cancer subtypes and is probably related to treatment response and prognosis. In this study, we investigated the relationship between AR expression and treatment response in HER2-positive breast cancer patients treated with HP neoadjuvant therapy. (2) Methods: We evaluated early breast cancer patients treated with HP neoadjuvant therapy from Jan. 2019 to Oct. 2020 at Peking University First Hospital Breast Cancer Center. The inclusion criteria were as follows: early HER2-positive breast cancer patients diagnosed by core needle biopsy who underwent both HP neoadjuvant therapy and surgery. We compared the clinical and pathological features between pathological complete response (pCR) and non-pCR patients. (3) Results: We included 44 patients. A total of 90.9% of patients received neoadjuvant therapy of taxanes, carboplatin, trastuzumab and pertuzumab (TCHP), and the total pCR rate was 50%. pCR was negatively related to estrogen receptor (ER) positivity (OR 0.075 [95% confidence interval (CI) 0.008–0.678], p = 0.021) and positively related to high expression levels of AR (OR 33.145 [95% CI 2.803–391.900], p = 0.005). We drew a receiver operating characteristic (ROC) curve to assess the predictive value of AR expression for pCR, and the area under the curve was 0.737 (95% CI 0.585–0.889, p = 0.007). The optimal cutoff of AR for predicting pCR was 85%. (4) Conclusion: AR is a potential marker for the prediction of pCR in HER2-positive breast cancer patients treated with HP neoadjuvant therapy.

GLI3 and androgen receptor are mutually dependent for their malignancy-promoting activity in ovarian and breast cancer cells

Hedgehog signaling pathway has been previously elucidated to be inappropriately activated in many human cancers, including ovarian and breast cancer. However, mechanistic contribution of GLI3, one of the terminal effectors of the pathway, to ovarian and mammary cancer development is underexplored. In this study, we investigated whether GLI3 is necessary for the growth and migration of ovarian and breast cancer cells and further explored the underlying mechanism of GLI3-mediated oncogenesis. We report that GLI3 knockdown inhibited growth and migration of androgen receptor (AR)-positive ovarian and breast cancer cells, but not AR-negative ovarian and breast cancer cells. Furthermore, knockdown of AR expression was effective in inhibiting the growth and migration of AR-positive ovarian and breast cancer cells in the presence of GLI3, but not in GLI3 knockdown cells. Similarly, ectopic expression of AR promoted the growth and migration of AR-negative ovarian and breast cancer cells in the presence of GLI3, but not in GLI3 knockdown cells. GLI3 and AR co-immunoprecipitated each other. GLI3 expression was negatively associated with overall survival of ovarian or breast patients whose tumors expressed a high level of AR. Our findings suggest that GLI3 and AR not only physically interact, but also are mutually dependent for their malignancy-promoting activity in ovarian and breast cancer cells. GLI3-specific inhibitors may be novel therapeutics for AR-expressing ovarian and breast cancers.

Urinary microRNAs can predict response to abiraterone acetate in castration resistant prostate cancer: A pilot study.

Despite novel agents have been introduced to treat castration resistant prostate cancer (CRPC) during the last decade, up to one-third of CRPC patients face primary resistance to new generation compounds. Therefore, sensitive molecular tools are urgently needed for reliable treatment selection and response prediction. This study aimed to evaluate urinary miRNAs and blood circulating androgen receptor (AR) transcript level as a tool for noninvasive outcome prediction for CRPC patients undergoing abiraterone acetate (AA) therapy. Prostate cancer-specific miR-148a, -365, -375, and -429 were analyzed in 129 urine samples collected from 100 CRPC patients before and during AA therapy via quantitative reverse transcription PCR. To test the prognostic value, urinary miRNA levels alone, as well as combined with AR level were associated with progression-free survival (PFS) and overall survival (OS). Level of urinary miR-375 was the highest in CRPC in comparison to noncancerous controls, as well as in combination with miR-429 was predictive for short PFS in AA-treated patients (HR = 2.2, 95% CI: 1.1-4.2, p = 0.023). Especially high prognostic power of all analyzed miRNAs was observed in CRPC cases with high blood AR levels. For PFS prediction a tandem of miR-429 and high AR reached HR of 5.0 (95% CI: 2.2-11.8, p < 0.001), while for prediction of OS the best combination was demonstrated by miR-148a and AR with HR of 3.1 (95% CI: 1.4-7.1, p = 0.006). Urinary miRNAs could be used as prognostic biomarkers for CRPC patients to predict response to AA therapy, especially for the cases with high blood AR levels.

MicroRNA target-based network predicts androgen receptor-linked mycotoxin stress

Stress-responsive microRNAs (miRNAs) contribute to the regulation of cellular homeostasis or pathological processes, including carcinogenesis, by reprogramming target gene expression following human exposure to environmental or dietary xenobiotics. Herein, we predicted the targets of carcinogenic mycotoxin-responsive miRNAs and analyzed their association with disease and functionality. miRNA target-derived prediction indicated potent associations of oncogenic mycotoxin exposure with metabolism- or hormone-related diseases, including sex hormone-linked cancers. Mechanistically, the signaling network evaluation suggested androgen receptor (AR)-linked signaling as a common pivotal cluster associated with metabolism- or hormone-related tumorigenesis in response to aflatoxin B1 and ochratoxin A co-exposure. Particularly, high levels of AR and AR-linked genes for the retinol and xenobiotic metabolic enzymes were positively associated with attenuated disease biomarkers and good prognosis in patients with liver or kidney cancers. Moreover, AR-linked signaling was protective against OTA-induced genetic insults in human hepatocytes whereas it was positively involved in AFB1-induced genotoxic actions. Collectively, miRNA target network-based predictions provide novel clinical insights into the progression or intervention against malignant adverse outcomes of human exposure to environmental oncogenic insults.

Intrinsic Subtypes and Androgen Receptor Gene Expression in Primary Breast Cancer. A Meta-Analysis.

Simple SummaryBreast cancer (BC) is the second largest cause of death for cancer in women worldwide. Different studies have shown that the androgen receptor (AR), a cytoplasmic ligand-dependent transcription factor, may play a role as a marker of BC biology. We aimed to assess the clinical significance of AR gene expression in BC by meta-analysis of large-scale microarray transcriptomic datasets. Our findings suggest that high mRNA levels of AR have the potential to be a promising non-invasive prognostic biomarker for the identification of the less aggressive BC subtypes.The androgen receptor (AR) is frequently expressed in breast cancer (BC), but its association with clinical and biological parameters of BC patients remains unclear. Here, we investigated the association of AR gene expression according to intrinsic BC subtypes by meta-analysis of large-scale microarray transcriptomic datasets. Sixty-two datasets including 10315 BC patients were used in the meta-analyses. Interestingly, AR mRNA level is significantly increased in patients categorized with less aggressive intrinsic molecular subtypes including, Luminal A compared to Basal-like (standardized mean difference, SMD: 2.12; 95% confidence interval, CI: 1.88 to 2.35; p < 0.001) or when comparing Luminal B to Basal-like (SMD: 1.53; CI: 1.33 to 1.72; p < 0.001). The same trend was observed when analyses were performed using immunohistochemistry-based surrogate subtypes. Consistently, the AR mRNA expression was higher in patients with low histological grade (p < 0.001). Furthermore, our data revealed higher levels of AR mRNA in BC patients expressing either estrogen or progesterone receptors (p < 0.001). Together, our findings indicate that high mRNA levels of AR are associated with BC subgroups with the less aggressive clinical features.