Estrogen Receptor Positive Breast Cancer

Dissecting multiple ESR1-mutant cell models revealed the different clinical relevance of cell model engineering and identified high-confidence mutant-ER targets, such as NPY1R. These examples demonstrate how EstroGene2.0 helps investigate breast cancer's response to endocrine therapies and explore resistance mechanisms.

Using this adopted method, we are able to culture and passage purified hormone sensing (HS) cells that retain ER responsiveness upon estrogen stimulation in long-term culture. This culture system presents a valuable platform to study the events involved in initiation and evolution of ER-positive breast cancer.

We proved that this strategy is capable of targeting ERα for degradation through ubiquitination, leading to the inhibition of proliferation in ERα+ breast cancer cells and tamoxifen-resistant breast cancer cells. Furthermore, we investigated the mechanisms involved in overcoming resistance. By circumventing drug resistance associated with LBD mutations in ERα, our approach provides a promising avenue for the discovery of new therapeutic agents.

P3, N=510, Active, not recruiting, Olema Pharmaceuticals, Inc. | Recruiting --> Active, not recruiting

P2, N=100, Completed, Northwestern University | Recruiting --> Completed | Phase classification: P2b --> P2

This review describes how sex steroid hormones, particularly estrogens and androgens, affect stromal cells in the breast cancer microenvironment. We summarize recent findings focusing on the effects of ER/AR signaling in breast cancer cells on stromal cells, as well as the direct effects of ER/AR signaling in stromal cells.

P3, N=812, Recruiting, Hoffmann-La Roche | Trial completion date: Sep 2032 --> Dec 2030 | Trial primary completion date: Aug 2026 --> Mar 2027

Our results support the possibility to omit radiotherapy after breast-conserving surgery in a well-defined subgroup of women aged ≥ 65 years with low-risk, ER-positive, pT1N0 breast cancer receiving adjuvant endocrine therapy.

Our study suggests differential tamoxifen benefit by menopausal status. Improved long-term endocrine therapy prediction in premenopausal patients is needed and could involve molecular markers because standard tumor characteristics cannot predict benefit beyond 10 years.

P2, N=23, Not yet recruiting, Guangzhou Women and Children's Medical Center

P=N/A, N=419, Completed, MedSIR | Active, not recruiting --> Completed | Trial primary completion date: Oct 2024 --> May 2024

P=N/A, N=128, Not yet recruiting, Assiut University

P3, N=240, Recruiting, MedSIR | Not yet recruiting --> Recruiting | Initiation date: Sep 2024 --> Dec 2024

Therefore, we suggest that there is an underappreciated association between the HER2-low subtype and endocrine resistance. In this perspective piece, we explore the evidence linking the HER2-low subtype with the various pathways to endocrine resistance and suggest that there are signaling networks in HER2-low tumors that intersect endocrine resistance and can be effectively targeted.

Considering the estrogen receptor positive invasive breast cancer of no special type cases, we showed that TSR had a positive prognostic value with an optimal threshold of 10 %. This study is one of the first to show inverse correlations between tumoural stroma amount and intra- and peritumoural lymphocyte percentages, which supports the hypothesis that tumoural stroma can prevent the recruitment of lymphocytes around and within the tumour.

P1/2, N=136, Terminated, Sanofi | Trial completion date: Dec 2027 --> Nov 2024 | Active, not recruiting --> Terminated | Trial primary completion date: Dec 2027 --> Nov 2024; Sponsor decision to prematurely stop the study, not linked to any safety concern.

P1, N=31, Active, not recruiting, Eisai Inc. | Trial completion date: Aug 2025 --> Mar 2026

These results suggest that the suppression of FOXO3a and ERα led to the increased expression of TGF-α, EGFR, and HER2 and subsequent cell proliferation in Ful-R. This study highlights the potential development of therapeutic drugs targeting FOXO3a for the treatment of HER2-positive, estrogen, and progesterone receptor-negative her2-type proliferative breast cancers.

Mechanistically, increased p110α levels result from inhibited degradation by E3 ubiquitin ligase NEDD4L. These findings suggest N6AMT1 as a potential luminal breast cancer biomarker and highlight the N6AMT1-p110α pathway as a therapeutic target to sensitize cells to tamoxifen.

Further, IGFBP-3 expression was increased by treatment with the GPER1 agonist G-1 and attenuated upon treatment with P17, a YAP/TAZ inhibitor. These data suggest that IGFBP-3 modulates breast cancer cells and is a mediator of breast cancer cell response to fulvestrant and tamoxifen.

We term this method SAM-DNMT3A and show that induction of global DNA methylation is a unique vulnerability in ER-positive breast cancer suggesting a therapeutic approach. Our findings highlight the need of caution when using CRISPR based approaches for inducing DNA methylation and demonstrate a method for global induction of DNA methylation.

P2, N=333, Completed, Queen Mary University of London | Unknown status --> Completed

The epithelial alternatively spliced FGFR2 IIIb isoform was significantly enriched in ER+ breast cancer, while the mesenchymal FGFR2 IIIc isoform was significantly prevalent in HER2+ cancer. Increased levels of FGFR2 and IIIb splice isoforms are associated with less aggressive breast cancer phenotypes, while decreased levels of FGFR2 and increased IIIc splice isoform are associated with more aggressive phenotypes.

Using proximity ligation assays, we showed that VPC-260724 disrupts the interaction between ER-AF2 and the coactivator SRC-3 and reduces the expression of ER target genes in various breast cancer models including the tamoxifen resistant cell line TamR3. In conclusion, we developed a novel ER-AF2 binder, VPC-260724, which shows antiproliferative activity in ER-positive breast cancer models. The use of an ER-AF2 inhibitor in combination with current treatments may provide a novel complementary therapeutic approach to target treatment resistance in ER-positive breast cancer.

LTP in layer 4 to layer 2/3 synapses in the somatosensory cortex was also reduced in slices from letrozole-treated mice, showing deficits in structural and functional plasticity resulting from aromatase inhibition. Ovariectomized mice performed worse than intact control mice in the novel object recognition test but, surprisingly, letrozole treatment rescued this deficit.

Despite guidelines being national, there were significant differences in adherence between regions in Sweden. As the largest differences were between age groups invited and not invited to mammography screening intervention should focus on women < 40 and ≥ 75 years at diagnosis. Further studies are needed to find strategies to increase overall adherence to AET in early BC.

Computational biomarkers, representing spatial properties of the tumor proliferation and immune cell infiltrates, provided independent prognostic information beyond conventional IHC markers in BC. Integrating Ki67-entropy and CD8-immunogradient indicators into prognostic models can improve patient stratification with regard to BCSS.

P3, N=624, Active, not recruiting, Pfizer | Recruiting --> Active, not recruiting

High expression of ZBTB7A in triple-negative breast cancer is significantly associated with poor response to neoadjuvant chemotherapy. Our work furthers the understanding of KDM5-mediated gene regulation and identifies mediators of sensitivity to KDM5i.

Tamoxifen (1-[4-(2-dimethylaminoethoxy)-phenyl]-1,2- diphenylbut-1(Z)-ene) is a nonsteroidal antiestrogen prodrug which formed pharmacologically active metabolite, 4-hydroxytamoxifen, largely used for endocrine therapy in pre and postmenopausal women with ER-positive breast cancer...Hence, can serve as potential lead against alpha Estrogen receptor (ER-α). The online version contains supplementary material available at 10.1007/s40203-024-00282-5.

Vepdegestrant 200 mg QD was well tolerated in Japanese patients with ER+/HER2- advanced breast cancer with no notable differences in pharmacokinetics from Western patients.

This treatment schedule is likely feasible. It is difficult to draw strong conclusions on safety/toxicity given the small numbers, but these seem in keeping with other recent reports of neoadjuvant breast radiotherapy.

YS mutant BC cells induced the conversion of fibroblasts into CAFs, via YAP, which represent a potential therapeutic target which interrupt the functional interactions between mutant cells/TME and to be implemented in the novel therapeutic strategy of a subset of metastatic BC patients carrying the frequent Y537S mutations.

P1, N=33, Active, not recruiting, Eisai Co., Ltd. | Trial completion date: Aug 2024 --> Mar 2026 | Trial primary completion date: Aug 2024 --> Mar 2026

P2, N=77, Recruiting, Asan Medical Center

Our findings challenge existing perceptions of cell permeability, emphasizing the possibly incomplete understanding of the structural determinants vital for cellular uptake of peptide-like macromolecules. Notably, while α helicity and lipophilicity are positive indicators, they alone are insufficient to determine high cell permeability, as evidenced by our less helical, more flexible, and less lipophilic FTDR-stapled peptides.

In contrast, anastrozole and letrozole show lower binding affinities for HER2 and EGFR due to their simpler structures but are potent aromatase inhibitors, making them effective in treating estrogen receptor-positive (ER-positive) breast cancers. In conclusion, DFT and molecular docking studies affirm the suitability of lapatinib, tucatinib, and neratinib for HER2-positive cancers, while anastrozole and letrozole are effective in ER-positive cancers, emphasizing the role of molecular structure and binding affinity in optimizing cancer treatment strategies.

In addition, we have presented four enhancer reprogramming mechanisms (transcription factor cooperation, pioneer factor binding, dynamic assisted loading, and tethering) and the multiple enhancer-promoter contact models. Based on these mechanisms and models, this review proposes that the combination of multiple therapy strategies such as agonists/antagonists of SHRs plus endocrine therapy and the adoption of the latest sequencing technologies are expected to improve the efficacy of ER positive breast cancer treatment.

According to literature, and TailorX trial data, our study confirms the importance of ODX as a tool able to guide therapeutic choices and ensure patients the most appropriate adjuvant treatment.

Our findings suggest that NSDHL regulates the BCSC/tumor-initiating cell population in MCF-7 spheroids and xenograft tumors.

No abstract available

P1, N=62, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Oct 2024 --> Oct 2025