Breast Cancer Research最新文献

Resistance to endocrine therapies remains a major clinical hurdle in breast cancer. Mutations to estrogen receptor alpha (ERα) arise after continued therapeutic pressure. Next generation selective estrogen receptor modulators and degraders/downregulators (SERMs and SERDs) show clinical efficacy, but responses are often non-durable. A tyrosine to serine point mutation at position 537 in the ERα ligand binding domain (LBD) is among the most common and most pathogenic alteration in this setting. It enables endocrine therapy resistance by superceding intrinsic structural-energetic gatekeepers of ER hormone-dependence, it enhances metastatic burden by enabling neomorphic ER-dependent transcriptional programs, and it resists SERM and SERD inhibiton by reducing their binding affinities and abilities to antagonize transcriptional coregulator binding. However, a subset of SERMs and SERDs can achieve efficacy by adopting poses that force the mutation to engage in a new interaction that favors the therapeutic receptor antagonist conformation. We previously described a chemically unconventional SERM, T6I-29, that demonstrates significant anti-proliferative activities in Y537S ERα breast cancer cells. Here, we use a comprehensive suite of structural-biochemical, in vitro, and in vivo approaches to better T6I-29's activities in breast cancer cells harboring Y537S ERα. RNA sequencing in cells treated with T6I-29 reveals a neomorphic downregulation of DKK1, a secreted glycoprotein known to play oncogenic roles in other cancers. Importantly, we find that DKK1 is significantly enriched in ER + breast cancer plasma compared to healthy controls. This study shows how new SERMs and SERDs can identify new therapeutic pathways in endocrine-resistant ER + breast cancers.

Background: Poly (ADP-Ribose) polymerase inhibitors are approved for treatment of tumors with BRCA1/2 and other homologous recombination repair (HRR) mutations. However, clinical responses are often not durable and treatment may be detrimental in advanced cancer due to excessive toxicities. Thus we are seeking alternative therapeutics to enhance PARP-directed outcomes. In an effort to expand the clinical use of PARP inhibitors to HRR proficient tumors, several groups have tested combinations of DNA methyltransferase inhibitors and PARP inhibitors. While this approach attenuated tumor cell proliferation in preclinical studies, subsequent clinical trials revealed little benefit. We hypothesized that benefit for this drug combination would only be specific to HRR deficient tumors, due to their inability to enact high fidelity DNA repair with subsequent cell death.

Methods: We generated hypomorphic BRCA1 and BRCA2 variants of the HRR proficient triple negative breast cancer cell line MDA-MB-231. We compared therapeutic response features such as RAD51 focus formation, cell cycle fraction alterations, DNA damage accumulation, colony formation, and cell death of these and other cell lines with and without intrinsic BRCA1/2 mutations. Results were confirmed in BRCA1/2 intact and deficient xenografts and PDX.

Results: Our targeted variants and cells with intrinsic BRCA1/2 mutations responded to low dose combination therapeutic treatment by G2M stalling, compounded DNA damage, severely attenuated colony formation, and importantly, increased cell death. In contrast, the parental MDA-MB-231 cells and other HRR proficient cell lines produced smaller cell populations with short term treatment, but with much less cumulative DNA damage, and minimal cell death. In animal studies, our BRCA-engineered hypomorphs and several independent PDX models with clinically relevant BRCA mutations were acutely more vulnerable to this drug combination.

Conclusions: We conclude that low dose DNA methyltransferase inhibition can cooperate with low dose PARP inhibition to increase DNA damage predominantly in cells with HRR deficiencies, ultimately producing more cell death than in HRR proficient tumors. We predict that clinical benefit will more likely be apparent in patients with DNA repair defective tumors and are focusing clinical exploration of this drug combination in these patients, with the goals of enhancing tumor cell death at minimal toxicities.

Background: Hereditary predisposition to breast and ovarian cancer syndrome (HBOC) is a pathological condition with increased cancer risk, including breast (BC), ovarian cancer (OC), and others. HBOC pathogenesis is caused mainly by germline pathogenic variants (GPV) in BRCA1 and BRCA2 genes. However, other relevant genes are related to this syndrome diagnosis, prognosis, and treatment, including TP53, PALB2, CHEK2, ATM, etc. This study aimed to identify the prevalence of non-BRCA genes in HBOC patients of Northeast Mexico.

Methods: This multicentric study included 1285 patients with HBOC diagnosis from four oncologic centers in northeast Mexico from 2016 to 2023. Genomic and clinical data were analyzed based on multi-gene panel results and electronic records of the medical geneticist consultation. For the data analysis of qualitative and quantitative variants, JASP statistical software (version 0.18.1) was used, taking p < 0.05 as a significant result.

Results: We found that 32.7% of the patients had at least one GPV in non-BRCA genes. The five most frequent non-BRCA genes were CHEK2, PALB2, MUTYH, CDKN2A, and ATM. Among the group of non-BRCA genes, six are involved in the homologous repair pathway (HR), and three are related to DNA damage repair (DDR) pathways. In analyzing GPVs in molecular pathways, both have similar frequencies with no statistical difference for BC.

Conclusion: Multi-gene testing implementation improves the detection of often overlooked genes related to HBOC pathogenesis and treatment. Non-BRCA GPVs in Northern Mexico correspond to one-third of the HBOC cases, including HR and DDR pathways genes that would be misdiagnosed if not tested. HR patient carriers are potential targets of iPARP therapies. The optimal approach to cancer treatment for non-BRCA mutation carriers warrants further investigation to develop newer therapies.

Recent evidence indicates that endocrine resistance in estrogen receptor-positive (ER+) breast cancer is closely correlated with phenotypic characteristics of epithelial-to-mesenchymal transition (EMT). Nonetheless, identifying tumor tissues with a mesenchymal phenotype remains challenging in clinical practice. In this study, we validated the correlation between EMT status and resistance to endocrine therapy in ER+ breast cancer from a transcriptomic perspective. To confirm the presence of morphological discrepancies in tumor tissues of ER+ breast cancer classified as epithelial- and mesenchymal-phenotypes according to EMT-related transcriptional features, we trained deep learning algorithms based on EfficientNetV2 architecture to assign the phenotypic status for each patient utilizing hematoxylin & eosin (H&E)-stained slides from The Cancer Genome Atlas database. Our classifier model accurately identified the precise phenotypic status, achieving an area under the curve (AUC) of 0.886 at the tile-level and an AUC of 0.910 at the slide-level. Furthermore, we evaluated the efficacy of the classifier in predicting endocrine response using data from an independent ER+ breast cancer patient cohort. Our classifier achieved a predicting accuracy of 81.25%, and 88.7% slides labeled as endocrine resistant were predicted as the mesenchymal-phenotype, while 75.6% slides labeled as sensitive were predicted as the epithelial-phenotype. Our work introduces an H&E-based framework capable of accurately predicting EMT phenotype and endocrine response for ER+ breast cancer, demonstrating its potential for clinical application and benefit.

Background: Patients with estrogen receptor (ER)-positive breast cancer (BC) can be treated with endocrine therapy targeting ER, however, metastatic recurrence occurs in 25% of the patients who have initially been treated. Secreted proteins from tumors play important roles in cancer metastasis but previous methods for isolating secretory proteins had limitations in identifying novel targets.

Methods: We applied an in situ secretory protein labeling technique using TurboID to analyze secretome from tamoxifen-resistant (TAMR) BC. The increased expression of LGALS3BP was validated using western blotting, qPCR, ELISA, and IF. Chromatin immunoprecipitation was applied to analyze estrogen-dependent regulation of LGALS3BP transcription. The adhesive and angiogenic functions of LGALS3BP were evaluated by abrogating LGALS3BP expression using either shRNA-mediated knockdown or a neutralizing antibody. Xenograft mouse experiments were employed to assess the in vivo metastatic potential of TAMR cells and the LGALS3BP protein. Clinical evaluation of LGALS3BP risk was carried out with refractory clinical specimens from tamoxifen-treated ER-positive BC patients and publicly available databases.

Results: TAMR secretome analysis revealed that 176 proteins were secreted at least 2-fold more from MCF7/TAMR cells than from sensitive cells, and biological processes such as cell adhesion and angiogenesis were associated with the TAMR secretome. Galectin-3 binding protein (LGALS3BP) was one of the top 10 most highly secreted proteins in the TAMR secretome. The expression level of LGALS3BP was suppressed by estrogen signaling, which involves direct ERα binding to its promoter region. Secreted LGALS3BP in the TAMR secretome helped BC cells adhere to the extracellular matrix and promoted the tube formation of human umbilical vein endothelial cells. Compared with sensitive cells, xenograft animal experiments with MCF7/TAMR cells showed increased pulmonary metastasis, which completely disappeared in LGALS3BP-knockdown TAMR cells. Finally, higher levels of LGALS3BP were associated with poor prognosis in ER-positive BC patients treated with adjuvant tamoxifen in the clinic.

Conclusion: TAMR secretome analysis identified secretory proteins, such as LGALS3BP, that are involved in biological processes closely related to metastasis. Secreted LGALS3BP from the TAMR cells promoted adhesion of the cells to the extracellular matrix and vasculature formation, which may support metastasis of TAMR cells.

Background: Alcohol intake is associated with a higher risk of estrogen receptor-positive (ER+) breast cancer (BC), presumably through its confirmed ability to increase sex hormone levels. Whether consuming alcohol within the recommended limit of one serving per day increases sex hormone levels among postmenopausal women taking aromatase inhibitors (AI) to inhibit estrogen production remains unknown. Therefore, we compared sex hormone levels following white wine to levels following white grape juice among ER + BC survivors taking AIs.

Methods: In this 10-week randomized controlled two-period crossover trial conducted from September 2022 to July 2023 among 20 postmenopausal women on AIs, we examined within-person changes in sex hormone levels following 3 weeks of 5 ounces of white wine daily versus 3 weeks of 6 ounces of white grape juice daily, with each drinking period preceded by two-week washouts and drinking period sequence allocated by randomization.

Results: All 20 participants completed the trial. Compared to daily grape juice, daily wine led to decreases in total estradiol (11.1%, 95%confidence interval[CI] -49.8%,57.2%), free estradiol index (0.7%, 95%CI -2%,0.7%), and free estradiol concentration (7.7%, 95%CI -48%, 63.9%) but increases in estrone (13.8%, 95%CI -9.5%,43.1%), dehydroepiandrosterone sulfate (DHEAS; 11.4%, 95%CI -3.3%,28.4%), and testosterone (12.6%, 95%CI -0.8%,27.7%) and decreased sex hormone-binding globulin (SHBG; -2.7%, 95%CI -21.9%,21.2%).

Conclusions: Five ounces of white wine daily did not lead to statistically significant increases in estradiol, but it led to changes in other sex hormones suggesting higher BC risk. Whether this level of alcohol intake diminishes AI effectiveness warrants further investigation.

Trials registration: Clinicaltrials.gov NCT05423730 registered June 14, 2022.

Background: Neoadjuvant chemotherapy (NACT) is the standard-of-care treatment for patients with locally advanced breast cancer (LABC), providing crucial benefits in tumor downstaging. Clinical parameters, such as molecular subtypes, influence the therapeutic impact of NACT. Moreover, severe adverse events delay the treatment process and reduce the effectiveness of therapy. Although metabolic changes during cancer treatment are crucial determinant factors in therapeutic responses and toxicities, related clinical research remains limited.

Methods: One hundred paired blood samples were collected from 50 patients with LABC before and after a complete NACT treatment cycle. Untargeted metabolomics was used by liquid chromatography-mass spectrometry (LC-MS) to investigate the relationship between dynamically changing metabolites in serum and the responses and toxicities of NACT.

Results: Firstly, we observed significant alterations in serum metabolite levels pre- and post-NACT, with a predominant enrichment in the sphingolipid and amino acid metabolism pathways. Second, pre-treatment serum metabolites successfully predicted the therapeutic response and hematotoxicities during NACT. In particular, molecular subtype variations in favorable treatment responses are linked to acyl carnitine levels. Finally, we discovered that the therapeutic effects of NACT could be attributed to essential amino acid metabolism.

Conclusion: This study elucidated the dynamic changes in metabolism during NACT treatment, providing a possibility for developing responsive metabolic signatures for personalized NACT treatment.

Background: Epidemiological studies associate an increase in breast cancer risk, particularly triple-negative breast cancer (TNBC), with lack of breastfeeding. This is more prevalent in African American women, with significantly lower rate of breastfeeding compared to Caucasian women. Prolonged breastfeeding leads to gradual involution (GI), whereas short-term or lack of breastfeeding leads to abrupt involution (AI) of the breast. Our previous study utilizing a murine model demonstrated precancerous changes, specifically hyperplasia, a non-obligate precursor of breast cancer in the mammary glands of AI mice. Here we investigated mechanisms during early events of AI that prompts precancerous changes in mouse mammary glands.

Methods: Uniparous FVB/N mice were randomized to AI and GI on postpartum day 7 when all pups were removed from AI dams. GI dams were allowed to nurse the pups till day 31. Cell death kinetics and gene expression were assessed by TUNEL assay and qPCR respectively. Immune cell changes were investigated by flow cytometry, cytokine array and multiplex immunofluorescence. 3D-organoid cultures were used for in vitro assay of luminal progenitor cells.

Results: AI results in rapid cell death, DNA repair response, and immunosuppressive myeloid cells infiltration, leading to a chronically inflamed microenvironment. GI elicits a more controlled immune response and extended cell death. At the peak of cell death, AI glands harbored more immunosuppressive myeloid-derived suppressor cells (MDSCs) and CD206 + M2-like macrophages, known to promote oncogenic events, compared to GI glands. AI glands exhibit an enrichment of CCL9-producing MDSCs and CD206 + M2-like macrophages that promote expansion of ELF5 + /ERα- luminal cells, both in vitro and in vivo. Multiplex imaging of AI glands demonstrated an increase in ELF5 + /WNT5a + luminal cells alongside a reduction in the ELF5 + /ERα + population when involution appeared histologically complete. A significantly higher number of CD206 + cells in post involution AI gland attests to a chronically inflamed state induced by AI.

Conclusions: Our findings reveal significant disparities between AI and GI gland dynamics at the early phase of involution. CCL9, secreted by immune cells at the peak of cell death promotes expansion of Elf5 + /ERα- luminal progenitor cells, the putative precursors of TNBC connecting early events of AI with increased breast cancer risk.

Background: Primary luminal breast cancer cells lose their identity rapidly in standard tissue culture, which is problematic for testing hormone interventions and molecular pathways specific to the luminal subtype. Breast cancer organoids are thought to retain tumor characteristics better, but long-term viability of luminal-subtype cases is a persistent challenge. Our goal was to adapt short-term organoids of luminal breast cancer for parallel testing of genetic and pharmacologic perturbations.

Methods: We freshly isolated patient-derived cells from luminal tumor scrapes, miniaturized the organoid format into 5 µl replicates for increased throughput, and set an endpoint of 14 days to minimize drift. Therapeutic hormone targeting was mimicked in these "zero-passage" organoids by withdrawing β-estradiol and adding 4-hydroxytamoxifen. We also examined sulforaphane as an electrophilic stress and commercial nutraceutical with reported anti-cancer properties. Downstream mechanisms were tested genetically by lentiviral transduction of two complementary sgRNAs and Cas9 stabilization for the first week of organoid culture. Transcriptional changes were measured by RT-qPCR or RNA sequencing (RNA-seq), and organoid phenotypes were quantified by serial brightfield imaging, digital image segmentation, and regression modeling of volumetric growth rates.

Results: We achieved > 50% success in initiating luminal breast cancer organoids from tumor scrapes and maintaining them to the 14-day zero-passage endpoint. Success was mostly independent of clinical parameters, supporting general applicability of the approach. Abundance of ESR1 and PGR in zero-passage organoids consistently remained within the range of patient variability at the endpoint. However, responsiveness to hormone withdrawal and blockade was highly variable among luminal breast cancer cases tested. Combining sulforaphane with knockout of NQO1 (a phase II antioxidant response gene and downstream effector of sulforaphane) also yielded a breadth of organoid growth phenotypes, including growth inhibition with sulforaphane, growth promotion with NQO1 knockout, and growth antagonism when combined.

Conclusions: Zero-passage organoids are a rapid and scalable way to interrogate properties of luminal breast cancer cells from patient-derived material. This includes testing drug mechanisms of action in different clinical cohorts. A future goal is to relate inter-patient variability of zero-passage organoids to long-term outcomes.