Biology subjects

Lange, C. A.

Publications and source records attributed to Lange, C. A..

5 recordsLinked to original sources

bioRxiv2026

Depletion of BRCA1 Potentiates Progestin-Induced Cytoskeletal Changes in an Ovarian Cancer Cell Model

Individuals with Hereditary Breast and Ovarian Cancer (HBOC) syndrome carry BRCA1/2 mutations that predispose them to various cancers. Notably, this condition increases the risk of developing an aggressive ovarian cancer (OC) subtype known as high-grade serous ovarian cancer (HGSOC). The impact of progesterone (P4) on the development of OC subtypes remains unclear. Research suggests a potential interplay between Progesterone Receptor (PR) signaling and BRCA1/2 actions. BRCA1 regulates PR expression and transcriptional activity, while P4 can drive estrogen receptor/PR complexes to BRCA1 DNA binding motifs. Normal fallopian tube tissues from healthy BRCA1/2 carriers (the cells of origin for HGSOC) exhibit gene signatures similar to those in HGSOC only during the luteal phase of the menstrual cycle, when circulating P4 levels are elevated. This implies a potential role for PR/BRCA complexes in modulating OC initiation and progression. To explore this interaction, BRCA1 was depleted in an ES-2 PR-B+ OC cell models using CRISPR-mediated gene editing. We hypothesized that BRCA1 depletion would alter PR-mediated signaling and reveal novel regulatory mechanisms. Depletion of BRCA1 led to increased total basal PR protein levels and site-specific hyperphosphorylation at S294 and S81 following R5020 (synthetic progestin) treatment. RNA sequencing of NE-1 and KO-BRCA1 pools treated with R5020 identified a high-confidence set of BRCA1-dependent, R5020-induced genes predominately involved with migration and cytoskeletal organization. Transwell assays revealed that R5020 treatment stimulates migration, an effect amplified upon BRCA1 depletion. Inhibition of PIP5K1C using UNC3230 blocked R5020-induced migration in one of the KO-BRCA1 cell pools with pan-Rho inhibitor CT04 showing similar results. The Rac1 inhibitor EHT-1864 suppressed all R5020-induced migration. In contrast, co-treatment with a pan-ROCK1/2 inhibitor Y-27632 resulted in an increase in R5020-induced migration, which was further enhanced with BRCA1 depletion. Overall, these findings establish a crosstalk between BRCA1 and PR signaling, where BRCA1 depletion sensitizes OC cells to progestin-induced migration by altering PR phosphorylation and remodeling cytoskeletal organization via PIP5K1C, Rho-GTPase, and Rac1-dependent mechanisms.

cancer biology↗

bioRxiv2025

Progesterone receptors drive advanced breast cancer phenotypes including circulating tumor- and stem-like cell expansion in the context of ESR1 mutation

Endocrine therapy resistance remains a major challenge in the treatment of advanced estrogen receptor positive (ER+) breast cancer. This can be driven by acquired mutations in the estrogen receptor gene (ESR1), such as Y537S or D538G, that primarily emerge in patients with prior aromatase inhibitor therapy and results in constitutive estrogen-independent ER activity. Progesterone receptors (PR) are important modifiers of ER activity, in part via direct binding. We previously showed that PR mediates expansion of cancer stem-like cell (CSC) populations and promotes tamoxifen resistance in nuclear ER/PR transcriptional complexes. In this study, we sought to define whether PR function changes in the context of ESR1 mutations. PR readily interacted with wild type (WT), but not Y537S or D538G ERs. RNA-seq and ChIP-seq studies demonstrated that ER+ breast cancer models expressing Y537S ER exhibited a distinct response to progesterone. CSC populations were enhanced in Y537S ER+ cells compared to WT ER+ cells. PR knockdown demonstrated that this property required PR expression but was unresponsive to antiprogestins. Moreover, we identified PR-dependent transcriptional programs such as the unfolded protein response (UPR) that can be leveraged to target CSC populations in Y537S ESR1-mutant breast cancer. The UPR activator ErSO, but not UPR inhibitors, blocked expansion of CSCs in WT as well as Y537S ER+ models. Together, our findings demonstrate a critical interplay between PR and mutant ER function and provide insight into PR-driven pathways including hyperactivation of the stress-sensing UPR that can be exploited as potential therapeutic avenues in advanced ER+ breast cancer.

cancer biology↗

bioRxiv2025

Mineralocorticoid and glucocorticoid receptor interaction drives TGFB1-induced triple-negative breast cancer progression to metastasis

In triple-negative breast cancer (TNBC), p38 MAPK phosphorylates the glucocorticoid receptor (GR) at N-terminal Ser134 in response to cytokines, such as TGF{beta}1. Phospho-Ser134-GR (pSer134-GR) regulates genes that promote migratory/invasive behavior and altered metabolism. In addition to acting as ligands for GR, glucocorticoids also activate closely-related mineralocorticoid receptors (MR). Elevated MR activity via its physiological ligand aldosterone (aldo), mediates hypertension, inflammation and fibrosis. While GR/p-GR has been implicated in TNBC progression to metastasis, the contribution of MR remains unknown. The METABRIC dataset demonstrated significantly higher expression of MR transcripts in TNBC relative to luminal breast cancers. Further, high MR expression predicted worse overall survival in the KM-plotter database. We observed pSer134-GR- and p38-dependent association of cytoplasmic MR/p-GR complexes upon treatment of TNBC cells with TGF{beta}1, while nuclear MR-GR complexes predominated in response to dexamethasone (dex) and/or aldo. Cytoplasmic MR/p-GR complexes entered the nucleus within 4 hours. MR knockdown or inhibition with MR-selective antagonists (spironolactone, finerenone) significantly reduced aldo or TGF{beta}1-induced migratory and stemness properties. MR knockdown models exhibited reduced migration, attenuated stem cell expansion, and impaired metastasis to lungs following tail-vein injection, thereby phenocopying cells harboring phospho-mutant S134A-GR. MR activation by aldo or TGF{beta}1 transcriptionally upregulated both canonical MR-target genes (SGK1, ENaC1) and non-canonical target genes related to fibrosis (COL1A1, ICAM1 and CTGF). MR expression was essential for functionally intact p38 MAPK/p-Ser134-GR signaling downstream of TGF{beta}1 receptor activation. Our studies define a novel role of MR/p-GR complexes in regulation of TNBC cell migration, stemness potential, and metastasis. Pharmacological inhibition of MR with FDA-approved MR antagonists (MRAs) offers an exciting opportunity for improved clinical management of TNBC patients.

cancer biology↗

bioRxiv2025

Isoform-Specific Gene Regulation by Progesterone Receptors Drives Divergent Phenotypes in Breast Cancer Cells

Exposure to progesterone is a recognized risk factor for breast cancer, and PGR polymorphisms are associated with various malignancies. Two progesterone receptor (PR) isoforms, full length PR-B and truncated PR-A, are expressed from the PGR gene in breast tissue and play crucial roles in normal physiology and breast cancer progression. An imbalance in the expression ratio of these isoforms, favoring increased levels of PR-A, is common in breast cancer and is associated with resistance to tamoxifen in luminal A-type tumors. Notably, PRs have recently been implicated in promoting endocrine resistance and driving the expansion of cancer stem-like cell (CSC) populations. Despite this insight, the isoform-specific molecular and epigenetic mechanisms underlying PR action in estrogen receptor positive (ER+) breast cancers remain understudied. Phenotypic studies of T47D cell lines that express exclusively PR-A or PR-B showed that PR isoforms regulate divergent cell fates. PR-B-expressing cells have a higher proliferation rate, while PR-A-expressing cells produce more mammospheres. We profiled progesterone-driven gene expression in cells grown in both adherent (2D) and mammosphere (3D) growth conditions and found differential gene regulation by PR-A and PR-B that is consistent with the observed divergent phenotypes. Only the PR-A-driven gene signature of ER+ breast cancer cells maintained as non-adherent mammospheres robustly predicted poor clinical outcome in the METABRIC data set. We then performed CUT&RUN to identify the genomic binding patterns unique to each PR isoform and their suite of target genes. Our findings indicate that PR-A acts as a regulator of the cell cycle, while PR-B plays a pivotal role in metabolism and intracellular signaling. Our genomic profiling of PRs in this model system has unveiled novel isoform-specific functions of PR. This work has shifted our prior understanding of the role of PRs in gene regulation, offering potential insights for therapeutic interventions in ER+ breast cancer.

cancer biology↗

bioRxiv2020

PELP1/SRC-3-dependent regulation of metabolic kinases drives therapy resistant ER+ breast cancer

Recurrence of metastatic breast cancer stemming from acquired endocrine and chemotherapy resistance remains a health burden for women with luminal (ER+) breast cancer. Disseminated ER+ tumor cells can remain viable but quiescent for years to decades. Contributing factors to metastatic spread include the maintenance and expansion of breast cancer stem cells (CSCs). Breast CSCs frequently exist as a minority population in therapy resistant tumors. In this study, we show that cytoplasmic complexes composed of steroid receptor (SR) co-activators, PELP1 and SRC-3, modulate breast CSC expansion through upregulation of the HIF-activated metabolic target genes PFKFB3 and PFKFB4. Seahorse metabolic assays demonstrated that cytoplasmic PELP1 influences cellular metabolism by increasing both glycolysis and mitochondrial respiration. PELP1 interacts with PFKFB3 and PFKFB4 proteins, and inhibition of PFKFB3 and PFKFB4 kinase activity blocks PELP1-induced tumorspheres and protein-protein interactions with SRC-3. PFKFB4 knockdown inhibited in vivo emergence of circulating tumor cell (CTC) populations in mammary intraductal (MIND) models. Application of PFKFB inhibitors in combination with ER targeted therapies blocked tumorsphere formation in multiple models of advanced breast cancer, including tamoxifen (TamR) and paclitaxel (TaxR) resistant models and ER+ patient-derived organoids (PDxO). Together, our data suggest that PELP1, SRC-3, and PFKFBs cooperate to drive ER+ tumor cell populations that include CSCs and CTCs. SignificanceIdentifying non-ER pharmacological targets offers a useful approach to blocking metastatic escape from standard of care ER/estrogen (E2)-targeted strategies to overcome endocrine and chemotherapy resistance.

cancer biology↗