Estrogen Enhances the Cell Viability and Motility of Breast Cancer Cells through the ERα-ΔNp63-Integrin β4 Signaling Pathway

Navigating the Intricacies of Tumor Heterogeneity: An Insight into Potential Prognostic Breast Cancer Biomarkers

Breast cancer is a heterogeneous disease with diverse histological and molecular subtypes. Luminal breast tumors are the most diagnosed subtype. In luminal breast cancer, hormone receptors (including ER, PR, HER2) play a diagnostic and prognostic role. Despite the effectiveness of endocrine therapy in luminal breast tumors, tumor recurrence and resistance occur, and this may highlight evolutionary strategies for survival driven by stemness. In this review we thus consider the association between estrogen signaling and stemness in mediating tumor processes. Many studies report stemness as one of the factors promoting tumor progression. Its association with estrogen signaling warrants further investigation and provides an opportunity for the identification of novel biomarkers which may be used for diagnostic, prognostic, and therapeutic purposes. Breast cancer stem cells have been characterized (CD44+ CD24-) and their role in promoting treatment resistance and tumor recurrence widely studied; however, the complexity of tumor progression which also involve microenvironmental factors suggests the existence of more varied cell phenotypes which mediate stemness and its role in tumor progression.

Investigating the effect of hesperetin on estrogen receptor alpha (ERα) expression, phosphorylation and activity in MCF-7 cells

PURPOSE

The most common malignancy among women worldwide is breast cancer. The estrogen receptor plays a vital role in this cancer. One of the most well-known mechanisms that affects the activity of this receptor is its phosphorylation by protein kinase pathways. Hesperetin, a flavonoid abundant in citrus species such as lemons, grapefruits, and oranges, is the aglycone form of hesperidin. It has undergone thorough evaluation for its potential anti-cancer properties, particularly in the context of breast cancer. Studies have shown that hesperetin has an effect on intracellular kinase pathways. The aim of this study was to investigate the effect of hesperetin on the expression, phosphorylation and activity of estrogen receptor alpha (ERα) in MCF-7 breast cancer cell line.

STUDY DESIGN AND METHODS

MCF-7 cells were cultured in RPMI-1640 phenol red-free medium supplemented with charcoal-stripped FBS and treated with hesperetin. The MTT method was used to evaluate cell survival. The levels of the ERα protein and its phosphorylated form (Ser118) were determined via western blotting. A luciferase reporter vector was used to evaluate ERE activity.

RESULTS

The results of this study indicated that hesperetin reduced the survival of MCF-7 cells in a dose-dependent manner. The expression and phosphorylation (at Ser118) of the ERα significantly increased and decreased, respectively, in the groups treated with hesperetin. Hesperetin increased the activity of the ERα in the absence of E2, although these differences were not statistically significant. Conversely, in the presence of E2, hesperetin caused a significant decrease in receptor activity.

CONCLUSION

Based on the results of this study, it can be concluded that hesperetin has a significant effect on ERα expression, phosphorylation and activity.

Current understanding of the pathogenesis of placenta accreta spectrum disorder with focus on mitochondrial function

AIM

The refinement of assisted reproductive technology, including the development of cryopreservation techniques (vitrification) and ovarian stimulation protocols, makes frozen embryo transfer (FET) an alternative to fresh ET and has contributed to the success of assisted reproductive technology. Compared with fresh ET cycles, FET cycles were associated with better in vitro fertilization outcomes; however, the occurrence of pregnancy-induced hypertension, preeclampsia, and placenta accreta spectrum (PAS) was higher in FET cycles. PAS has been increasing steadily in incidence as a life-threatening condition along with cesarean rates worldwide. In this review, we summarize the current understanding of the pathogenesis of PAS and discuss future research directions.

METHODS

A literature search was performed in the PubMed and Google Scholar databases.

RESULTS

Risk factors associated with PAS incidence include a primary defect of the decidua basalis or scar dehiscence, aberrant vascular remodeling, and abnormally invasive trophoblasts, or a combination thereof. Freezing, thawing, and hormone replacement manipulations have been shown to affect multiple cellular pathways, including cell proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and mitochondrial function. Molecules involved in abnormal migration and EMT of extravillous trophoblast cells are beginning to be identified in PAS placentas. Many of these molecules were also found to be involved in mitochondrial biogenesis and dynamics.

CONCLUSION

The etiology of PAS may be a multifactorial genesis with intrinsic predisposition (e.g., placental abnormalities) and certain environmental factors (e.g., defective decidua) as triggers for its development. A distinctive feature of this review is its focus on the potential factors linking mitochondrial function to PAS development.

A network map of cytoskeleton-associated protein 4 (CKAP4) mediated signaling pathway in cancer

Cytoskeleton-associated protein 4 (CKAP4) is a non-glycosylated type II transmembrane protein that serves as a cell surface-activated receptor. It is expressed primarily in the plasma membranes of bladder epithelial cells, type II alveolar pneumocytes, and vascular smooth muscle cells. CKAP4 is involved in various biological activities including cell proliferation, cell migration, keratinocyte differentiation, glycogenesis, fibrosis, thymic development, cardiogenesis, neuronal apoptosis, and cancer. CKAP4 has been described as a pro-tumor molecule that regulates the progression of various cancers, including lung cancer, breast cancer, esophageal squamous cell carcinoma, hepatocellular carcinoma, cervical cancer, oral cancer, bladder cancer, cholangiocarcinoma, pancreatic cancer, myeloma, renal cell carcinoma, melanoma, squamous cell carcinoma, colorectal cancer, and osteosarcoma. CKAP4 and its isoform bind to DKK1 or DKK3 (Dickkopf proteins) or antiproliferative factor (APF) and regulates several downstream signaling cascades. The CKAP4 complex plays a crucial role in regulating the signaling pathways including PI3K/AKT and MAPK1/3. Recently, CKAP4 has been recognized as a potential target for cancer therapy. Due to its biomedical importance, we integrated a network map of CKAP4. The available literature on CKAP4 signaling was manually curated according to the NetPath annotation criteria. The consolidated pathway map comprises 41 activation/inhibition events, 21 catalysis events, 35 molecular associations, 134 gene regulation events, 83 types of protein expression, and six protein translocation events. CKAP4 signaling pathway map data is freely accessible through the WikiPathways Database ( https://www.wikipathways.org/index.php/Pathway:WP5322 ). Generation of CKAP4 signaling pathway map.

Application of silver nanoparticles for improving motor recovery after spinal cord injury via reduction of pro-inflammatory M1 macrophages

Silver nanoparticles (AgNPs) possess anti-inflammatory activities and have been widely deployed for promoting tissue repair. Here we explored the efficacy of AgNPs on functional recovery after spinal cord injury (SCI). Our data indicated that, in a SCI rat model, local AgNPs delivery could significantly recover locomotor function and exert neuroprotection through reducing of pro-inflammatory M1 survival. Furthermore, in comparison with Raw 264.7-derived M0 and M2, a higher level of AgNPs uptake and more pronounced cytotoxicity were detected in M1. RNA-seq analysis revealed the apoptotic genes in M1 were upregulated by AgNPs, whereas in M0 and M2, pro-apoptotic genes were downregulated and PI3k-Akt pathway signaling pathway was upregulated. Moreover, AgNPs treatment preferentially reduced cell viability of human monocyte-derived M1 comparing to M2, supporting its effect on M1 in human. Overall, our findings reveal AgNPs could suppress M1 activity and imply its therapeutic potential in promoting post-SCI motor recovery.

Heat Shock Factor 1 (HSF1) cooperates with estrogen receptor α (ERα) in the regulation of estrogen action in breast cancer cells

Heat shock factor 1 (HSF1), a key regulator of transcriptional responses to proteotoxic stress, was linked to estrogen (E2) signaling through estrogen receptor α (ERα). We found that an HSF1 deficiency may decrease ERα level, attenuate the mitogenic action of E2, counteract E2-stimulated cell scattering, and reduce adhesion to collagens and cell motility in ER-positive breast cancer cells. The stimulatory effect of E2 on the transcriptome is largely weaker in HSF1-deficient cells, in part due to the higher basal expression of E2-dependent genes, which correlates with the enhanced binding of unliganded ERα to chromatin in such cells. HSF1 and ERα can cooperate directly in E2-stimulated regulation of transcription, and HSF1 potentiates the action of ERα through a mechanism involving chromatin reorganization. Furthermore, HSF1 deficiency may increase the sensitivity to hormonal therapy (4-hydroxytamoxifen) or CDK4/6 inhibitors (palbociclib). Analyses of data from The Cancer Genome Atlas database indicate that HSF1 increases the transcriptome disparity in ER-positive breast cancer and can enhance the genomic action of ERα. Moreover, only in ER-positive cancers an elevated HSF1 level is associated with metastatic disease.

About 70% of breast cancers rely on supplies of a hormone called estrogen – which is the main hormone responsible for female physical characteristics – to grow. Breast cancer cells that are sensitive to estrogen possess proteins known as estrogen receptors and are classified as estrogen-receptor positive. When estrogen interacts with its receptor in a cancer cell, it stimulates the cell to grow and migrate to other parts of the body. Therefore, therapies that decrease the amount of estrogen the body produces, or inhibit the receptor itself, are widely used to treat patients with estrogen receptor-positive breast cancers.

When estrogen interacts with an estrogen receptor known as ERα it can also activate a protein called HSF1, which helps cells to survive under stress. In turn, HSF1 regulates several other proteins that are necessary for ERα and other estrogen receptors to work properly. Previous studies have suggested that high levels of HSF1 may worsen the outcomes for patients with estrogen receptor-positive breast cancers, but it remains unclear how HSF1 acts in breast cancer cells.

Vydra, Janus, Kuś et al. used genetics and bioinformatics approaches to study HSF1 in human breast cancer cells. The experiments revealed that breast cancer cells with lower levels of HSF1 also had lower levels of ERα and responded less well to estrogen than cells with higher levels of HSF1. Further experiments suggested that in the absence of estrogen, HSF1 helps to keep ERα inactive. However, when estrogen is present, HSF1 cooperates with ERα and enhances its activity to help cells grow and migrate. Vydra, Janus, Kuś et al. also found that cells with higher levels of HSF1 were less sensitive to two drug therapies that are commonly used to treat estrogen receptor-positive breast cancers.

These findings reveal that the effect HSF1 has on ERα activity depends on the presence of estrogen. Therefore, cancer therapies that decrease the amount of estrogen a patient produces may have a different effect on estrogen receptor-positive tumors with high HSF1 levels than tumors with low HSF1 levels.

Integrin β4 as a Potential Diagnostic and Therapeutic Tumor Marker

Integrin β4 (ITGβ4) is a class of transmembrane adhesion molecules composed of hemidesmosomes (HDs). Its unique long intracellular domain provides intricate signal transduction functions. These signal transduction effects are especially prominent in tumors. Many recent studies have shown that integrin β4 is differentially expressed in various tumors, and it plays a vital role in tumor invasion, proliferation, epithelial–mesenchymal transition, and angiogenesis. Therefore, we categorize the research related to integrin β4, starting from its structure and function in tumor tissues, and provide a basic description. Based on its structure and function, we believe that integrin β4 can be used as a tumor marker. In clinical practice, it is described as a diagnostic marker for the targeted treatment of cancer and will be helpful in the clinical diagnosis and treatment of tumors.

CNA2Subpathway: identification of dysregulated subpathway driven by copy number alterations in cancer

Biological pathways reflect the key cellular mechanisms that dictate disease states, drug response and altered cellular function. The local areas of pathways are defined as subpathways (SPs), whose dysfunction has been reported to be associated with the occurrence and development of cancer. With the development of high-throughput sequencing technology, identifying dysfunctional SPs by using multi-omics data has become possible. Moreover, the SPs are not isolated in the biological system but interact with each other. Here, we propose a network-based calculated method, CNA2Subpathway, to identify dysfunctional SPs is driven by somatic copy number alterations (CNAs) in cancer through integrating pathway topology information, multi-omics data and SP crosstalk. This provides a novel way of SP analysis by using the SP interactions in the system biological level. Using data sets from breast cancer and head and neck cancer, we validate the effectiveness of CNA2Subpathway in identifying cancer-relevant SPs driven by the somatic CNAs, which are also shown to be associated with cancer immune and prognosis of patients. We further compare our results with five pathway or SP analysis methods based on CNA and gene expression data without considering SP crosstalk. With these analyses, we show that CNA2Subpathway could help to uncover dysfunctional SPs underlying cancer via the use of SP crosstalk. CNA2Subpathway is developed as an R-based tool, which is freely available on GitHub (https://github.com/hanjunwei-lab/CNA2Subpathway).

Zinc oxide nanoparticles enhance expression of maspin in human breast cancer cells

Toxic and apoptotic impacts of zinc oxide nanoparticle (ZNP) on different cancer cells have been reported. Maspin (a mammary serine protease inhibitor) as a tumor suppressor gene can inhibit tumor growth and metastasis. The expression of maspin is modulated by p53, Bcl-2 family genes, and estrogen receptor α (ER-α). This study aimed to assess the ZNP effects on maspin expression in MCF-7 cells (a breast cancer cell). Experimental groups (ZNP5, ZNP10, and ZNP20) received 5, 10, and 20 μM/mL ZNP for 48 h, respectively. 17-β-estradiol (E2) was used to evaluate the role of ER-α in the anticancer impact of ZNP. Cell viability, Annexin V, migration assay, gene expression, and western blotting methods were applied to evaluate ZNP effects on the MCF-7 cells. ZNP at the concentrations of 10 and 20 μM/mL could significantly decrease the viability and migration rate, and significantly increase apoptosis percentage in the MCF-7 cells. ZNP significantly enhanced mRNA expression and protein level of maspin in MCF-7 cells in a concentration-dependent way. ZNP concentration-dependently elevated mRNA expression and protein level of p53 and Bax while reduced the expression of Bcl-2 and ER-α. E2 promoted cancer cell growth by enhancing survival and migration rates. E2 treatment reduced mRNA expression and protein level of maspin and p53, and elevated Bcl-2 expression. ZNP considerably changed these events induced by E2 in the MCF-7 cells. It is concluded that the maspin overexpression is one of the toxic mechanisms of the ZNP on the ER-α-positive breast cancer cells, and can suppress the migration of these cells.

H19-Dependent Transcriptional Regulation of β3 and β4 Integrins Upon Estrogen and Hypoxia Favors Metastatic Potential in Prostate Cancer

Estrogen and hypoxia promote an aggressive phenotype in prostate cancer (PCa), driving transcription of progression-associated genes. Here, we molecularly dissect the contribution of long non-coding RNA H19 to PCa metastatic potential under combined stimuli, a topic largely uncovered. The effects of estrogen and hypoxia on H19 and cell adhesion molecules’ expression were investigated in PCa cells and PCa-derived organotypic slice cultures (OSCs) by qPCR and Western blot. The molecular mechanism was addressed by chromatin immunoprecipitations, overexpression, and silencing assays. PCa cells’ metastatic potential was analyzed by in vitro cell-cell adhesion, motility test, and trans-well invasion assay. We found that combined treatment caused a significant H19 down-regulation as compared with hypoxia. In turn, H19 acts as a transcriptional repressor of cell adhesion molecules, as revealed by up-regulation of both β3 and β4 integrins and E-cadherin upon H19 silencing or combined treatment. Importantly, H19 down-regulation and β integrins induction were also observed in treated OSCs. Combined treatment increased both cell motility and invasion of PCa cells. Lastly, reduction of β integrins and invasion was achieved through epigenetic modulation of H19-dependent transcription. Our study revealed that estrogen and hypoxia transcriptionally regulate, via H19, cell adhesion molecules redirecting metastatic dissemination from EMT to a β integrin-mediated invasion.

p63 at the Crossroads between Stemness and Metastasis in Breast Cancer

After lung cancer, breast cancer (BC) is the most frequent cause of cancer death among women, worldwide. Although advances in screening approaches and targeted therapeutic agents have decreased BC incidence and mortality, over the past five years, triple-negative breast cancer (TNBC) remains the breast cancer subtype that displays the worst prognosis, mainly due to the lack of clinically actionable targets. Genetic and molecular profiling has unveiled the high intrinsic heterogeneity of TNBC, with the basal-like molecular subtypes representing the most diffuse TNBC subtypes, characterized by the expression of basal epithelial markers, such as the transcription factor p63. In this review, we will provide a broad picture on the physiological role of p63, in maintaining the basal epithelial identity, as well as its involvement in breast cancer progression, emphasizing its relevance in tumor cell invasion and stemness.

MicroRNA-22 inhibits proliferation, invasion and metastasis of breast cancer cells through targeting truncated neurokinin-1 receptor and ERα

HEADING AIMS

This topic aims to clarify whether miR-22 directly targets and downregulates the expression of ERα and NK1R-Tr to inhibit the malignant behaviors of breast cancer cells.

MATERIALS AND METHODS

RT-PCR and Western Blotting were used to detect the expression profile of miR-22, NK1R-Tr and ERα. Luciferase reporter assay and CHIP experiment were conducted to investigate the regulation network between miR-22, NK1R-Tr and ERα. MCF-7-ERαI and MDA-MB-231-ERα cell lines were constructed to study the biological behaviors. The SP-NK1R-ERK1/2 signaling pathway was analyzed using Western Blotting. The subcutaneous and metastases tumor models were employed to study the effects of miR-22 on cell proliferation and metastasis of breast cancer cells in vivo.

KEY FINDINGS

MiR-22 expression level was significantly lower in breast cancerous tissues and cell lines than the adjacent normality, while that of NK1R-Tr increased. The ERα could positively regulate NK1R-Tr expression at DNA level. The descent degree of NK1R-Tr in MCF-7-ERαI cells was far less than that in wild MCF-7 cells, while the findings in MDA-MB-231-ERα cells was more apparent than wild MDA-MB-231 cells. The malignant phenotype was decreased in miR-22 overexpressing cells compared with the wild type. The peak of ERK1/2 phosphorylation was delayed and weakened in miR-22 overexpressing MCF-7 cells, which was agreed with the findings using NK1R-Tr antagonist. The size and number of metastatic tumors declined compared to the controls.

SIGNIFICANCE

MiR-22 downregulated the expression of NK1R-Tr and ERα to delay and weaken phosphorylation of ERK1/2 to inhibit proliferation and metastasis of breast cancer cells.

Ethanol Enhances Estrogen Mediated Angiogenesis in Breast Cancer

Angiogenesis, a highly regulated process, is exploited by tumors like breast cancer to ensure a constant supply of oxygen and nutrients and is key for tumor survival and progression. Estrogen and alcohol independently have been observed to contribute to angiogenesis in breast cancer but their combinatorial effects have never been evaluated. The exact mechanism by which estrogen and alcohol contribute to breast cancer angiogenesis remains to be elucidated. In this study, we defined the in vitro effects of the combination of estrogen and alcohol in breast cancer angiogenesis using the tubulogenesis and scratch wound assays. Conditioned media, generated by culturing the murine mammary cancer cell line, TG1-1, in estrogen and ethanol, enhanced tubule formation and migration as well as modulated the MAP Kinase pathway in the murine endothelial cell line, SVEC4-10. Additionally, estrogen and ethanol in combination enhanced the expression of the pro-angiogenic factors VEGF, MMP-9, and eNOS, and modulated Akt activation. These observations suggest that TG1-1 cells secrete pro-angiogenic molecules in response to the combination of estrogen and ethanol that modulate the morphological and migratory properties of endothelial cells. The data presented in this study, is the first in attempting to link the cooperative activity between estrogen and ethanol in breast cancer progression, underscoring correlations first made by epidemiological observations linking the two.

Essential role of endogenous prolactin and CDK7 in estrogen-induced upregulation of the prolactin receptor in breast cancer cells

Our early studies have shown that Estradiol (E₂)/Estrogen Receptor α (ER) in a non-DNA dependent manner through complex formation with C/EBPβ/SP1 induced transcriptional activation of the generic hPIII promoter and expression of the Prolactin Receptor (PRLR) receptor in MCF-7 cells. Subsequent studies demonstrated effects of unliganded ERα with requisite participation of endogenous PRL on the activation of PRLR transcription. Also, EGF/ERBB1 in the absence of PRL and E₂ effectively induced upregulation of the PRLR. In this study we have delineated the transcriptional mechanism of upregulation of PRLR receptor induced by E₂ incorporating knowledge of the various transcriptional upregulation modalities from our previous studies. Here, we demonstrate an essential requirement of STAT5a induced by PRL via PRLR receptor which associates at the promoter and its interaction with phoshoERα S118. Knock-down of PRL by siRNA significantly reduced E₂-induced PRLR promoter activity, mRNA and protein expression, recruitment of ERα to the complex at promoter, C/EBPβ association to its DNA site and productive complex formation at hPIII promoter. The specific CDK7 inhibitor (THZ1) that attenuates E₂-induced ERα phosphorylation at S118 abrogated E₂-induced PRLR promoter activation. Further studies demonstrated that E₂ induced cell migration was inhibited by PRL siRNA and THZ1 indicating its dependence on PRL/PRLR and CDK7, respectively. Our studies have demonstrated the essential role of endogenous PRL and CDK7 in the upregulation of PRLR by E₂ and provide insights for therapeutic approaches that will mitigate the transcription/expression of PRLR and its participation in breast cancer progression fueled by E₂ and PRL via their cognate receptors.

Mechanisms of action of nonpeptide hormones on resveratrol-induced antiproliferation of cancer cells

Nonpeptide hormones, such as thyroid hormone, dihydrotestosterone, and estrogen, have been shown to stimulate cancer proliferation via different mechanisms. Aside from their cytosolic or membrane-bound receptors, there are receptors on integrin α_v β₃ for nonpeptide hormones. Interaction between hormones and integrin α_v β₃ can induce signal transduction and eventually stimulate cancer cell proliferation. Resveratrol induces inducible COX-2-dependent antiproliferation via integrin α_v β₃ . Resveratrol and hormone-induced signals are both transduced by activated extracellular-regulated kinases 1 and 2 (ERK1/2); however, hormones promote cell proliferation, while resveratrol induces antiproliferation in cancer cells. Hormones inhibit resveratrol-stimulated phosphorylation of p53 on Ser15, resveratrol-induced nuclear COX-2 accumulation, and formation of p53-COX-2 nuclear complexes. Subsequently, hormones impair resveratrol-induced COX-2-/p53-dependent gene expression. The inhibitory effects of hormones on resveratrol action can be blocked by different antagonists of specific nonpeptide hormone receptors but not integrin α_v β₃ blockers. Results suggest that nonpeptide hormones inhibit resveratrol-induced antiproliferation in cancer cells downstream of the interaction between ligand and receptor and ERK1/2 activation to interfere with nuclear COX-2 accumulation. Thus, the surface receptor sites for resveratrol and nonpeptide hormones are distinct and can induce discrete ERK1/2-dependent downstream antiproliferation biological activities. It also indicates the complex pathways by which antiproliferation is induced by resveratrol in various physiological hormonal environments. .