The relationship between the Hippo signaling pathway and bone metastasis of breast cancer

WISP1 inhibition of YAP phosphorylation drives breast cancer growth and chemoresistance via TEAD4 activation

Wnt1-inducible signaling pathway protein 1 (WISP1) promotes breast cancer. The Hippo signaling pathway demonstrates a potential connection with WISP1, necessitating an exploration of their interaction. This study hypothesized that WISP1 boosts breast cancer by modulating the Hippo signaling pathway. The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases were used to analyze WISP1 expression and Hippo signaling in breast cancer patients. WISP1, yes-associated protein (YAP), and domain family member 4 (TEAD4) were overexpressed or silenced in breast cancer cells. Epithelial-mesenchymal transition (EMT), and chemoresistance of breast cancer cells were evaluated. Immunofluorescence, PCR, immunoprecipitation, and western blot were used to detect the expression of WISP1 and key Hippo signaling factors and their interactions. Enrichment analysis indicated activation of WISP1 and Hippo signaling pathway and correlated with a worse prognosis in breast cancer. WISP1 overexpression facilitated EMT and chemotherapy resistance in breast cancer. Importantly, overexpression of WISP1 promoted YAP's nuclear translocation. TEAD4 expression in YAP precipitates from nuclear of WISP1-overexpressing MCF-7 cells increased. The promoting effect of WISP1 on breast cancer was counteracted by silencing YAP or TEAD4. Moreover, in WISP1 small interfering RNA-transfected MCF-7 cells, p-YAP expression increased, while interaction between YAP and TEAD4 decreased. WISP1 silencing led to ubiquitin increase and TEAD reduction in the p-YAP precipitates. In conclusion, WISP1 promotes YAP nuclear translocation and binding with TEAD4 by inhibiting YAP phosphorylation, reducing ubiquitin recruitment, and participating in transcriptional regulation in breast cancer.

Molecular mechanisms of Hippo pathway in tumorigenesis: therapeutic implications

The Hippo signaling pathway is a pivotal regulator of tissue homeostasis, organ size, and cell proliferation. Its dysregulation is profoundly implicated in various forms of cancer, making it a highly promising target for therapeutic intervention. This review extensively evaluates the mechanisms underlying the dysregulation of the Hippo pathway in cancer cells and the molecular processes linking these alterations to tumorigenesis. Under normal physiological conditions, the Hippo pathway is a guardian, ensuring controlled cellular proliferation and programmed cell death. However, numerous mutations and epigenetic modifications can disrupt this equilibrium in cancer cells, leading to unchecked cell proliferation, enhanced survival, and metastatic capabilities. The pathway's interaction with other critical signaling networks, including Wnt/β-catenin, PI3K/Akt, TGF-β/SMAD, and EGFR pathways, further amplifies its oncogenic potential. Central to these disruptions is the activation of YAP and TAZ transcriptional coactivators, which drive the expression of genes that promote oncogenesis. This review delves into the molecular mechanisms responsible for the dysregulation of the Hippo pathway in cancer, elucidating how these disruptions contribute to tumorigenesis. We also explore potential therapeutic strategies, including inhibitors targeting YAP/TAZ activity and modulators of upstream signaling components. Despite significant advancements in understanding the Hippo pathway's role in cancer, numerous questions remain unresolved. Continued research is imperative to unravel the complex interactions within this pathway and to develop innovative and effective therapies for clinical application. In conclusion, the comprehensive understanding of the Hippo pathway's regulatory mechanisms offers significant potential for advancing cancer therapies, regenerative medicine, and treatments for chronic diseases. The translation of these insights into clinical practice will necessitate collaborative efforts from researchers, clinicians, and pharmaceutical developers to bring novel and effective therapies to patients, ultimately improving clinical outcomes and advancing the field of oncology.

Targeting Yes-Associated Protein (YAP) in Breast Cancer: In Silico Molecular Dynamics, Luminescence-Based In Vitro, and In Vivo Validation of Rauvolfia tetraphylla-Derived Inhibitors

The study aims to elucidate the pharmacological mechanism of Rauvolfia tetraphylla against breast cancer through a comprehensive, multi-faceted approach. This includes molecular docking, molecular dynamics, and experimental validation. Initial screening via ADME analysis and network pharmacology identified key compounds and potential targets. Protein-protein interaction (PPI) network analysis pinpointed Yes-associated protein-1 (YAP) as a crucial target. Molecular docking revealed that three compounds-ajmaline, reserpine, and serpentine-exhibited strong binding affinities with YAP, with scores of -6.5 to -6.7 kcal/mol. Molecular dynamics simulations were conducted to assess the stability of these interactions further. Experimental validation showed R. tetraphylla inhibited breast cancer cell proliferation, with an IC50 of 348.69 μg/mL, while demonstrating cytoprotective effects on Vero cells (IC50: 1056.23 μg/mL). Migration assays indicated an 88.5% reduction in cell migration, and increased ROS levels signaled elevated stress in cancer cells. Apoptosis was confirmed by AO/EtBr staining. In vivo validation in a DMBA-induced mouse model confirmed significant tumor growth inhibition, supported by changes in YAP expression and histopathological analysis. These findings highlight R. tetraphylla as a promising therapeutic candidate against breast cancer, offering insights into its mechanisms and potential for future drug development and clinical applications.

Regulation of hippo signaling mediated apoptosis by Rauvolfia tetraphylla in triple-negative breast cancer

Rauvolfia tetraphylla is an essential medicinal plant that has been widely used in traditional medicine for various disease treatments. However, the tumor suppressor activity of R. tetraphylla and its phytocompounds were not explored against triple-negative breast cancer. The current research investigated the impact of R. tetraphylla methanolic extract (RTE) and its isolated compounds Ajmaline (RTC1) and Reserpine (RTC2) on triple-negative breast cancer cell line (MDA-MB-231) focusing on anti-proliferative effects. Our study imparts that RTE and RTC2 showed promising cytotoxic effects compared to RTC1. So further experiments have proceeded with RTE and RTC2, to evaluate its proliferation, migration, and apoptotic effect. The result shows around 80% of cells were observed in the G0/G1 phase in cell cycle analysis indicating the cell cycle inhibition and duel staining clearly showed the apoptotic effect. The migration of cells after the scratch was 60.45% observed in control and 90% in treated cells showing the inhibition of migration. ROS distribution was intense compared to control indicating the increased ROS stress in treated cells. Both RTE and RTC2-treated cells showed the potential to suppress proliferation and induce apoptotic change by upregulating BAX and MST-1 and suppressing Bcl2, LATS-1, and YAP, proving that deregulation of YAP resulting in the blockage of TEAD-YAP complex and inhibit proliferation. Therefore, R. tetraphylla extract and its isolated compounds were demonstrated to find its ability to act against MDA-MB-231 and these findings will help adjudicate it as a therapeutic drug against experimental triple-negative breast cancer.

Molecular characterization of breast cancer cell pools with normal or reduced ability to respond to progesterone: a study based on RNA-seq

BACKGROUND

About one-third of patients with estrogen receptor alpha (ERα)-positive breast cancer have tumors which are progesterone receptor (PR) negative. PR is an important prognostic factor in breast cancer. Patients with ERα-positive/PR-negative tumors have shorter disease-free and overall survival than patients with ERα-positive/PR-positive tumors. New evidence has shown that progesterone (P4) has an anti-proliferative effect in ERα-positive breast cancer cells. However, the role of PR in breast cancer is only poorly understood.

METHODS

We disrupted the PR gene (PGR) in ERα-positive/PR-positive T-47D cells using the CRISPR/Cas9 system. This resulted in cell pools we termed PR-low as P4 mediated effects were inhibited or blocked compared to control T-47D cells. We analyzed the gene expression profiles of PR-low and control T-47D cells in the absence of hormone and upon treatment with P4 alone or P4 together with estradiol (E2). Differentially expressed (DE) genes between experimental groups were characterized based on RNA-seq and Gene Ontology (GO) enrichment analyses.

RESULTS

The overall gene expression pattern was very similar between untreated PR-low and untreated control T-47D cells. More than 6000 genes were DE in control T-47D cells upon stimulation with P4 or P4 plus E2. When PR-low pools were subjected to the same hormonal treatment, up- or downregulation was either blocked/absent or consistently lower. We identified more than 3000 genes that were DE between hormone-treated PR-low and control T-47D cells. GO analysis revealed seven significantly enriched biological processes affected by PR and associated with G protein-coupled receptor (GPCR) pathways which have been described to support growth, invasiveness, and metastasis in breast cancer cells.

CONCLUSIONS

The present study provides new insights into the complex role of PR in ERα-positive/PR-positive breast cancer cells. Many of the genes affected by PR are part of central biological processes of tumorigenesis.