Migration Of Triple-negative Breast Cancer Cells Research Articles

The Antimicrobial Peptide Merecidin Inhibit the Metastasis of Triple-Negative Breast Cancer by Obstructing EMT via miR-30d-5p/Vimentin.

Purpose: To investigate the inhibitory effect of antimicrobial peptide merecidin on triple-negative breast cancer (TNBC) and the mechanism of inhibiting epithelial-mesenchymal transformation (EMT) by regulating miR-30d-5p/vimentin. Methods: TNBC cell lines (MDA-MB-231, MDA-MB-468) were treated with merecidin to assess proliferation, migration, invasion ability, and EMT. Confocal laser localization was used to examine the role of merecidin and TNBC cells. The relationship between merecidin and miR-30d-5p was determined through RT-qPCR and dual-luciferase reporter gene, and the relationship between merecidin and vimentin was verified through pulling down the experiment. The effects of miR-30d-5p on the migration and invasion ability of TNBC cells were confirmed through scratch and transwell experiments. Vimentin levels, tumor volume, shape, size, and weight were observed in the MDA-MB-231 subcutaneous tumor model in nude mice. Results: merecidin inhibited the proliferation, migration, invasion, and EMT of TNBC cells. merecidin was primarily located in the cytoplasm of TNBC cells, and the expression of miR-30d-5p was low in TNBC cells. merecidin significantly up-regulated the expression of miR-30d-5p. miR-30d-5p negatively regulated vimentin. merecidin could bind to vimentin in vitro. miR-30d-5p inhibited the migration and invasion ability of TNBC cells, while vimentin promoted their migration and invasion ability. Down-regulation of miR-30d-5p or overexpression of vimentin partially counteracted the inhibitory effects of merecidin on TNBC cell migration, invasion ability, and EMT. In nude mouse tumor models, merecidin significantly suppressed tumor growth. Conclusion: Merecidin effectively blocks the EMT process and inhibits the migration and invasion of TNBC cells by regulating miR-30d-5p/vimentin.

ROR2 promotes invasion and chemoresistance of triple-negative breast cancer cells by activating PI3K/AKT/mTOR signaling.

This study aimed to investigate the role of receptor tyrosine kinase-like orphan receptor 2 (ROR2) in triple-negative breast cancer (TNBC). ROR2 expression in primary TNBC and metastatic TNBC tissues was analyzed by immunohistochemical staining and PCR. ROR2 expression in TNBC cell lines was detected by PCR and Western blot analysis. The migration, invasion and chemosensitivity of TNBC cells with overexpression or knockdown of ROR2 were examined. ROR2 expression was high in metastatic TNBC tissues. ROR2 knockdown suppressed the migration, invasion and chemoresistance of TNBC cells. ROR2 overexpression in MDA-MB-435 cells promoted the migration, invasion, and chemoresistance. Moreover, ROR2 knockdown in HC1599 and MDA-MB-435 adriamycin-resistant cells enhanced chemosensitivity to adriamycin. ROR2 could activate PI3K/AKT/mTOR signaling in TNBC cells. ROR2 is upregulated and promotes metastatic phenotypes of TNBC by activating PI3K/AKT/mTOR signaling.

Upregulated bone morphogenetic protein 8A (BMP8A) in triple negative breast cancer (TNBC) and its involvement in the bone metastasis.

The present study aimed to investigate the involvement of aberrant BMP8A expression in TNBC and bone metastasis. Aberrant expression of BMP8A in breast cancer was first determined by analyzing The Cancer Genome Atlas breast cancer cohort (TCGA-BRCA) and an immunohistochemical (IHC) staining of BMP8A in a breast cancer tissue microarray (TMA). Clinical relevance of deregulated BMP8A in breast cancer was assessed using Kaplan-Meier online analysis. The influence of BMP8A on cellular functions of two TNBC cell lines was assessed using in vitro assays. Conditional medium (CM) collected from the supernatant of hFOB cells and bone matrix extract (BME) was applied to mimic the bone micro-environment to evaluate the role played by BMP8A in bone metastasis. Correlations with both osteolytic and osteoblastic markers were evaluated in the TCGA-BRCA cohort. Expression of certain responsive genes was quantified in the BMP8A overexpression cell lines. Additionally, signal transduction through both Smad-dependent and independent pathways was evaluated using Western blot assay. Compared to the adjacent normal tissues, BMP8A expression was significantly increased in primary tumors (p < 0.05) which was associated with shorter distant metastasis free survival (DMFS) in TNBC (p < 0.05). BMP8A was observed to enhance cell invasion and migration within TNBC cells. In the simulated bone milieu, both MDA-MB-231BMP8Aexp and BT549BMP8Aexp cells presented enhanced invasiveness. BMP8A level was strongly correlated with most osteolytic and osteoblastic markers, suggesting the potential involvement of BMP8A in bone metastasis in TNBC. Receptor activator of nuclear factor kappa-B ligand (RANKL) expression was significantly increased in BMP8A overexpressed triple-negative cell lines (MDA-MB-231 and BT549). Furthermore, enhanced phosphorylation of Smad3 and increased expression of epidermal growth factor receptor (EGFR) were observed in MDA-MB-231 cells overexpressing BMP8A. BMP8A was upregulated in TNBC which was associated with poorer DMFS. BMP8A overexpression enhanced the invasion and migration of TNBC cells. With a putative role in osteolytic bone metastasis in TNBC, BMP8A represents a promising candidate for further investigation into its therapeutic potential.

Unveiling the therapeutic potential: KBU2046 halts triple-negative breast cancer cell migration by constricting TGF-β1 activation in vitro.

Triple-negative breast cancer (TNBC) is a heterogeneous, recurring cancer characterized by a high rate of metastasis, poor prognosis, and lack of efficient therapies. KBU2046, a small molecule inhibitor, can inhibit cell motility in malignant tumors, including breast cancer. However, the specific targets and the corresponding mechanism of its function remain unclear. In this study, we employed (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium) (MTS) assay and transwell assay to investigate the impact of KBU2046 on the proliferation and migration of TNBC cells in vitro. RNA-Seq was used to explore the targets of KBU2046 that inhibit the motility of TNBC. Finally, confirmed the predicted important signaling pathways through RT-qPCR and western blotting. In this study, we found that KBU2046 functioned as a novel transforming growth factor-β (TGF-β1) inhibitor, effectively suppressing tumor cell motility in vitro. Mechanistically, it directly down-regulated leucine-rich repeat-containing 8 family, member E (LRRC8E), latent TGFβ-binding protein 3 (LTBP3), dynein light chain 1 (DNAL1), and MAF family of bZIP transcription factors (MAFF) genes, along with reduced protein expression of the integrin family. Additionally, KBU2046 decreased phosphorylation levels of Raf and ERK. This deactivation of the ERK signaling pathway impeded cancer invasion and metastasis. In summary, these findings advocate for the utilization of TGF-β1 as a diagnostic and prognostic biomarker and as a therapeutic target in TNBC. Furthermore, our data underscore the potential of KBU2046 as a novel therapeutic strategy for combating cancer metastasis.

Cross-border regulation of the STK39/MAPK14 pathway by Lycium barbarum miR166a to inhibit triple-negative breast cancer.

To investigate the effects of Lycium barbarum miRNA166a (Lb-miR166a) on human gene expression regulation during the therapy for triple-negative breast cancer (TNBC). Transcriptome sequencing was used to analyze the distribution and composition of miRNA in Lycium barbarum fruit. Lb-miR166a was introduced into TNBC MB-231 cells by lentiviral transfection to study its effects on cell proliferation, apoptosis, invasion, and metastasis both in vivo and in vitro. Bioinformatic and dual-luciferase assays identified the target gene of Lb-miR166a. The role of STK39 in TNBC progression was elucidated through clinical data analysis combined with cellular studies. The influence of Lb-miR166a on the STK39/MAPK14 pathway was confirmed using a target-specific knockout MB-231 cell line. Lb-miR166a was found to be highly expressed in Lycium barbarum. It inhibited MB-231 cell proliferation, invasion, and metastasis, and promoted apoptosis. STK39 was overexpressed in TNBC and was associated with increased invasiveness and poorer patient prognosis. Gene enrichment analysis and dual-luciferase assays demonstrated that Lb-miR166a regulates STK39 expression cross-border and inhibits MAPK14 phosphorylation, impacting the phosphorylation of downstream target genes. The downregulation of STK39 and subsequent inhibition of MAPK14 phosphorylation by Lb-miR166a leads to reduced proliferation, migration, and invasion of TNBC cells. These findings suggest a novel therapeutic strategy for TNBC treatment, highlighting possible clinical applications of Lb-miR166a in managing this aggressive cancer type.

The use of MFAP2 for diagnosis, prognosis and immunotherapy of triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is characterized by significant heterogeneity, presenting a formidable challenge with a poor prognosis and a deficiency of efficacious treatment options. In this comprehensive study, we investigated the multifaceted role of Microfibril-associated glycoprotein 2 (MFAP2) in TNBC using a combination of bioinformatics analysis involving Gene Expression Omnibus (GEO), OncoDB, UALCAN, Human Protein Atlas (HPA), TIMER, STRING, DAVID, and GSCA databases and in vitro experiments, such as cell culture, MFAP2 gene knockdown, RT-qPCR, western Blot, colony formation, Cell counting kit-8, and wound healing assays. Our findings demonstrated a significant up-regulation of MFAP2 mRNA in TNBC cell lines, emphasizing its potential as a diagnostic biomarker. Validation across multiple datasets further affirmed the elevated expression of MFAP2 in TNBC tissues, underscoring its prognostic relevance. Notably, our study revealed a correlation between MFAP2 expression and immune cell infiltration, suggesting its role in shaping the tumor microenvironment. STRING analysis unveiled interactions with proteins involved in elastic fibers and extracellular matrix constituents. Furthermore, KEGG pathway analysis highlighted enrichment in the TGF-beta signaling pathway, implicating MFAP2 in key cancer-related processes. Drug sensitivity analysis identified potential therapeutic targets, supporting MFAP2's utility in personalized treatment strategies. In vitro experiments corroborated the oncogenic impact of MFAP2, demonstrating its influence on TNBC cell proliferation and migration. These comprehensive findings position MFAP2 as a promising biomarker and therapeutic target in TNBC, offering valuable insight for future research and clinical application.

Demethylase FTO inhibits the occurrence and development of triple-negative breast cancer by blocking m 6A-dependent miR-17-5p maturation-induced ZBTB4 depletion.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer, and its mechanisms of occurrence and development remain unclear. In this study, we aim to investigate the role and molecular mechanisms of the demethylase FTO (fat mass and obesity-associated protein) in TNBC. Through analysis of public databases, we identify that FTO may regulate the maturation of miR-17-5p and subsequently influence the expression of zinc finger and BTB domain-containing protein 4 (ZBTB4), thereby affecting the occurrence and progression of TNBC. We screen for relevant miRNAs and mRNAs from the GEO and TCGA databases and find that the FTO gene may play a crucial role in TNBC. In vitro cell experiments demonstrate that overexpression of FTO can suppress the proliferation, migration, and invasion ability of TNBC cells and can regulate the maturation of miR-17-5p through an m 6A-dependent mechanism. Furthermore, we establish a xenograft nude mouse model and collect clinical samples to further confirm the role and impact of the FTO/miR-17-5p/ZBTB4 regulatory axis in TNBC. Our findings unveil the potential role of FTO and its underlying molecular mechanisms in TNBC, providing new perspectives and strategies for the research and treatment of TNBC.

LTBP1 promotes the progression of triple negative breast cancer via activating the RhoA/ROCK signaling pathway

&lt;p class="MsoNormal" style="text-align: justify;"&gt;&lt;span lang="EN-US"&gt;The latent transforming growth factor-beta (TGF-&amp;beta;) binding protein 1 (LTBP1) has been implicated in various cellular processes, but its role in triple-negative breast cancer (TNBC) remains unclear. In this study, we investigated the impact of LTBP1 on TNBC progression and its underlying mechanisms. Analysis of online datasets revealed elevated LTBP1 mRNA expression in breast cancer tissues compared to normal adjacent tissues. Kaplan-Meier Plotter analysis indicated that high LTBP1 expression was negatively correlated with relapse-free survival (RFS), distant-metastasis free survival (DMFS), and overall survival (OS) of breast cancer patients. Additionally, LTBP1 mRNA levels were associated with chemotherapy resistance. Functional assays in TNBC cells demonstrated that LTBP1 knockdown suppressed cell proliferation, induced apoptosis, and attenuated migration and invasion. In vivo studies confirmed that LTBP1 knockdown inhibited tumor growth in a xenograft mouse model. Mechanistically, LTBP1 positively correlated with genes involved in signaling regulation and organelle organization, with significant associations to GTPase binding and the RhoA/ROCK pathway. LTBP1 knockdown reduced RhoA activity and phosphorylation of Myosin Light Chain 2 (MLC2), suggesting inhibition of the RhoA/ROCK signaling pathway. Moreover, activation of the RhoA/ROCK pathway partially rescued the effects of LTBP1 knockdown on TNBC cell proliferation, apoptosis, migration, and invasion. In conclusion, our findings suggest that LTBP1 promotes TNBC progression through activation of the RhoA/ROCK signaling pathway, highlighting its potential as a therapeutic target for TNBC.&lt;/span&gt;&lt;/p&gt;

LncRNA PSMA3-AS1 activates the progression of triple-negative breast cancer cells by blocking miR-186-5p-mediated PSME3 inhibition.

Triple-negative breast cancer (TNBC) is an aggressive malignant tumor with a high death rate in the whole world. This cancer mainly occurs in young women group possessed with poor prognoses. Long noncoding RNAs (lncRNAs) are known for regulating human diseases and cancers. Even though growing researches have illuminated that lncRNAs have a close relation with TNBC progression, the function of lncRNAPSMA3 antisense RNA 1 (PSMA3-AS1) in TNBC has not been discussed and exposed yet. In the present research, the expression pattern and functional role of PSMA3-AS1 were analyzed and unveiled with the help of RT-qPCR and functional assays. The findings demonstrated that PSMA3-AS1 was notably upregulated in TNBC cells. Silencing of PSMA3-AS1 had suppressing effects on TNBC cell growth and migration. Mechanistically, PSMA3-AS1 induced upregulation of proteasome activator subunit 3 (PSME3) by functioning as a miR-186-5p sponge. Furthermore, rescue assays certified that overexpression of PSME3 or inhibition of miR-186-5p could abrogate the inhibiting role of silenced PSMA3-AS1 on TNBC cell functions. To summarize, PSMA3-AS1 abolishes miR-186-5p-mediated suppression on PSME3 to accelerate TNBC progression.

TRIM21-mediated Sohlh2 ubiquitination suppresses M2 macrophage polarization and progression of triple-negative breast cancer

Lung metastasis is the major cause of death in patients with triple-negative breast cancer (TNBC). Tumor-associated macrophages (TAMs) represent the M2-like phenotype with potent immunosuppressive activity, and play a pro-tumor role in TNBC lung metastasis. Sohlh2 belongs to the basic helix-loop-helix transcription factor family. However, its role in macrophages polarization remains unknown, especially in TNBC progression. Here we demonstrated that Sohlh2 overexpression promoted M2 macrophage polarization. Moreover, high expression of Sohlh2 in M2-like macrophage enhanced TNBC cell growth, migration and lung metastasis in vivo and in vitro. Mechanistically, we revealed that Sohlh2 functioned through up-regulating LXRα, ABCA1, ABCG1 expression and disturbing the lipid homeostasis on the membrane of macrophages. Sohlh2 could directly bind to the promoter of LXRα and promote its transcription activity. E3 ubiquitin ligase TRIM21 promoted Sohlh2 ubiquitination and degradation, and suppressed M2 macrophage polarization and TNBC progression. Collectively, our findings suggested that Sohlh2 in macrophage could be a novel therapeutic target for TNBC metastatic treatment.

PAK inhibitor FRAX486 decreases the metastatic potential of triple-negative breast cancer cells by blocking autophagy

BackgroundTriple-negative breast cancer (TNBC) is a unique breast cancer subtype with a high risk of metastasis and recurrence and a poor prognosis. Epithelial-mesenchymal transition (EMT) endows epithelial cells with the ability to move to distant sites, which is essential for the metastasis of TNBC to organs, including the lung. Autophagy, an intracellular degradation process that involves formation of double-layered lipid autophagosomes that transport cytosolic cargoes into lysosomes via autophagosome–lysosome fusion, is involved in various diseases, including cancer and neurodegenerative, metabolic, cardiovascular, and infectious diseases. The relationship between autophagy and cancer has become relatively clear. However, research on pharmacological drugs that block cancer EMT by targeting autophagy is still in the initial stages. Therefore, the re-evaluation of old drugs for their potential in blocking both autophagy and EMT was conducted.MethodsMore than 2000 small molecule chemicals were screened for dual autophagy/EMT inhibitors, and FRAX486 was identified as the best candidate inhibitor of autophagy/EMT. The functions of FRAX486 in TNBC metastasis were detected by CCK-8, migration and wound healing assays. The effects of FRAX486 on autophagy and its target PAK2 were determined by immunoblotting, immunofluorescence, immunoprecipitation analysis and transmission electron microscopy. The findings were validated in mouse models.ResultsHere, we report that FRAX486, a potent P21-activated kinase 2 (PAK2) inhibitor, facilitates TNBC suppression both in vitro and in vivo by blocking autophagy. Mechanistically, FRAX486 inhibits autophagy in TNBC cells by targeting PAK2, leading to the ubiquitination and proteasomal degradation of STX17, which mediates autophagosome–lysosome fusion. The inhibition of autophagy by FRAX486 causes upregulation of the epithelial marker protein E-cadherin and thus suppresses the migration and metastasis of TNBC cells.ConclusionsThe effects of FRAX486 on TNBC metastasis suppression were verified to be dependent on PAK2 and autophagy inhibition. Together, our results provide a molecular basis for the application of FRAX486 as a potential treatment for inhibiting the metastasis of TNBC.

Nuclear isoform of RAPH1 interacts with FOXQ1 to promote aggressiveness and radioresistance in breast cancer

Radioresistance limits the efficacy of radiotherapy against breast cancer, especially the most lethal subtype of breast cancer, triple-negative breast cancer (TNBC). Epithelial-to-mesenchymal transition (EMT) is closely related to tumor radioresistance. In this work, we attempted to identify the key EMT-related transcription factor(s) that can induce radioresistance in breast cancer cells. A set of 44 EMT transcription factors were analyzed in parental and radioresistant TNBC cell lines. The function of FOXQ1, a differentially expressed transcription factor, was determined in TNBC radioresistance. FOXQ1-interacting proteins were identified by co-immunoprecipitation and mass spectrometry. Compared with parental cells, FOXQ1 was significantly upregulated in radioresistant TNBC cells. Silencing of FOXQ1 increased the radiosensitiviy of radioresistant TNBC cells both in vitro and in vivo. FOXQ1 associated with a nuclear isoform of RAPH1 (named RAPH1-i3) in radioresistant TNBC cells. Overexpression of RAPH1-i3 enhanced TNBC cell proliferation and migration, and most interestingly, induced radioresistance in parental TNBC cells when co-expressed with FOXQ1. Similar findings were observed in estrogen receptor-positive breast cancer cell lines that had co-expression of RAPH1-i3 and FOXQ1. Mechanistically, co-expression of RAPH1-i3 and FOXQ1 activated STAT3 signaling and increased the expression of CCND1, MCL1, Bcl-XL, and MMP2. Depletion of RAPH1-i3 impaired the radioresistance of radioresistant TNBC cells. Additionally, RAPH1-i3 upregulation was associated with advanced tumor stage and reduced disease-free survival in TNBC patients. These results collectively show that RAPH1-i3 interacts with FOXQ1 to promote breast cancer progression and radioresistance. RAPH1-i3 and FOXQ1 represent therapeutic targets for the treatment of breast cancer including TNBC.

AURKAIP1 actuates tumor progression through stabilizing DDX5 in triple negative breast cancer

Aurora-A kinase interacting protein 1 (AURKAIP1) has been proved to take an intermediary role in cancer by functioning as a negative regulator of Aurora-A kinase. However, it remains unclear whether and how AURKAIP1 itself would directly engage in regulating malignancies. The expression levels of AURKAIP1 were detected in triple negative breast cancer (TNBC) by immunohistochemistry and western blots. The CCK8, colony formation assays and nude mouse model were conducted to determine cell proliferation whereas transwell and wound healing assays were performed to observe cell migration. The interaction of AURKAIP1 and DEAD-box helicase 5 (DDX5) were verified through co-immunoprecipitation and successively western blots. From the results, we found that AURKAIP1 was explicitly upregulated in TNBC, which was positively associated with tumor size, lymph node metastases, pathological stage and unfavorable prognosis. AURKAIP1 silencing markedly inhibited TNBC cell proliferation and migration in vitro and in vivo. AURKAIP1 directly interacted with and stabilized DDX5 protein by preventing ubiquitination and degradation, and DDX5 overexpression successfully reversed proliferation inhibition induced by knockdown of AURKAIP1. Consequently, AURKAIP1 silencing suppressed the activity of Wnt/β-catenin signaling in a DDX5-dependent manner. Our study may primarily disclose the molecular mechanism by which AURKAIP1/DDX5/β-catenin axis modulated TNBC progression, indicating that AURKAIP1 might serve as a therapeutic target as well as a TNBC-specific biomarker for prognosis.

TNFRSF19 promotes endoplasmic reticulum stress-induced paraptosis via the activation of the MAPK pathway in triple-negative breast cancer cells.

TNFRSF19 is a member of the tumor necrosis factor receptor superfamily, and its function exhibits variability among different types of cancers. The influence of TNFRSF19 on triple-negative breast cancer (TNBC) has yet to be definitively established. In this study, bioinformatics analyses revealed that lower TNFRSF19 was associated with the poorer prognosis, higher lymph node metastasis and lower immune infiltration. Subsequently, data obtained from the TCGA database and collection of tissue samples revealed that the mRNA and protein expression levels of TNFRSF19 were observed to be significantly reduced in TNBC tissue compared to normal tissue. Additionally, the results of in vitro experiments have demonstrated that TNFRSF19 possessed the ability to inhibit the proliferation, migration and invasive capabilities of TNBC cells. In vivo trials elucidated that TNFRSF19 could suppress tumor xenografts growth. Mechanistically, TNFRSF19 initiated caspase-independent cell death and induced paraptosis. Moreover, rescue assays demonstrated that TNFRSF19 induced-paraptosis was facilitated by MAPK pathway-mediated endoplasmic reticulum (ER) stress. In conclusion, our findings demonstrated that the upregulation of TNFRSF19 functioned as a tumor suppressor in TNBC by stimulating paraptosis through the activation of the MAPK pathway-mediated ER stress, highlighting its potential to be a new therapeutic target for TNBC.

MicroRNA‑606 inhibits the growth and metastasis of triple‑negative breast cancer by targeting Stanniocalcin1.

Triple‑negative breast cancer (TNBC) is associated with a poor prognosis; however, treatments for TNBC are limited, with poor outcomes. MicroRNAs (miRNAs/miRs) are small non‑coding RNA molecules that are able to regulate gene expression. The present study aimed to identify differentially expressed miRNAs inpatients with breast cancer, and to investigate the functional role of the identified miRNA targets and their effects invitro and invivo. Transfection with miR‑606 suppressed TNBC cell proliferation, migration, invasion and tumor sphere‑forming ability, as determined using trypan blue, Transwell and sphere formation assays. Moreover, miR‑606 induced the apoptosis of TNBC cells, as determined by flow cytometric analysis. Furthermore, intratumoral injections of miR‑606 mimics suppressed tumor growth in MDA‑MB‑231 xenografts. In addition, MDA‑MB‑231 cells transfected with miR‑606 mimics exhibited decreased lung metastatic nodules in a mouse tail vein injection model. Notably, miR‑606 and STC1 expression had opposing effects on the overall survival ofpatients with TNBC. The results of the present study suggested a novel tumor suppressor function for miR‑606 in TNBC, thus indicating its potential application in the development of anticancer miRNA therapeutics.

Downregulation of TAB182 promotes cancer stem-like cell properties and therapeutic resistance in triple-negative breast cancer cells

TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.

Natural polyphenol-loaded cross-linked lipoic acid vesicles treat triple-negative breast cancer by cancer cell killing and metastasis inhibition

The high incidence of metastases remains a major hurdle for triple negative breast cancer (TNBC) treatment. Herein, we developed a fairly safe anticancer nanodrug for TNBC treatment by loading Epigallocatechin-3-gallate (EGCG) in cross-linked lipoic acid vesicles (EGCG@cLAVs), which cannot only directly kill TNBC cells through inducing apoptosis, but also significantly suppress the TNBC metastasis by metalloproteinases (MMPs) inhibition, a key event in tumor extracellular matrix (ECM) remodeling. The cytotoxicity assay revealed that the ICEGCG50 of EGCG@cLAVs (85.1 μM) fell in the range of common cytotoxic drugs. The in vitro antimetastasis results disclosed that the EGCG@cLAVs effectively suppressed the migration and invasion of TNBC cells (4T1) with low wound healing rate and relative invasion rate of 19.10 ± 2.12% and 15.0 ± 1.63%, 4.0 and 6.7 times lower than that of control, respectively. The outcomes of animal models revealed that EGCG@cLAVs not only achieved the comparable antitumor effect to that of first-line chemotherapeutic drug DOX, but also reduced the number of lung metastatic nodules from 31.4 (DOX) to 1.4. This nanodrug provides a promising candidate for TNBC therapy.

The chromatin architectural regulator SND1 mediates metastasis in triple-negative breast cancer by promoting CDH1 gene methylation

BackgroundSND1 participates in tumorigenesis, tumour invasion and metastasis in different cancers. Previous studies have shown that SND1 can promote the invasion and migration of breast cancer cells. Triple-negative breast cancer (TNBC) is a specific breast cancer subtype with high metastatic potential and poor prognosis. However, the specific roles and mechanisms of SND1 in TNBC metastasis remain unaddressed.MethodsImmunostaining was used to detect the SND1 expression in tissue samples of 58 TNBC and 10 glioblastomas (GBM) as positive control. The correlation between SND1 expression and patient prognosis was assessed using the Kaplan–Meier estimator. The gene expression was evaluated by qRT-PCR, Western blot and immunofluorescence analyses. Gene Ontology analysis, ChIP, a dual-luciferase reporter assay, EMSA, and 3C analysis were applied to identify SND1-activated target genes. Bisulfite sequencing PCR and MeDIP were used to detect DNA methylation. We also used wound healing, Transwell and orthotopic implantation assays to investigate the function of SND1 in TNBC cell migration and invasion.ResultsThe data of immunohistochemistry manifested that SND1 is the overexpression in metastasized TNBC and an independent factor for TNBC prognosis. SND1 knockdown inhibited the migration and invasion of TNBC cells. We found that SND1 promotes the metastatic phenotype of TNBC cells by epigenetically altering chromatin conformational interactions, which in turn activates DNMT3A transcription. Then, DNMT3A attenuates CCND1 expression by inducing CCND1 gene methylation, leading to TNBC metastasis.ConclusionSND1 can promote the invasion and migration of TNBC cells by promoting DNMT3A expression and suppressing CDH1 activity. SND1 is a potential biomarker and a promising therapeutic target for TNBC.

Inhibition of CD36 and Nogo-B expression inhibited the proliferation and migration of triple negative breast cancer cells

Cluster of differentiation 36 (CD36) is a membrane glycoprotein receptor capable of binding and transporting fatty acid. Nogo-B regulates the metabolism of fatty acids in the liver and affects the development of liver cancer. To date, it remains unclear whether the interaction between CD36 and Nogo-B affects the proliferation and migration of breast cancer cells. In the current study, we aimed to determine whether the interference of CD36 and Nogo-B affects the proliferation and migration of triple-negative breast cancer (TNBC) cells. The results showed that inhibition of CD36 or Nogo-B alone can inhibit the proliferation and migration of TNBC cells, and the inhibitory effect was more pronounced when CD36 and Nogo-B were inhibited simultaneously. Meanwhile, it was found that inhibition of CD36 and Nogo-B expression can inhibit the expression of Vimentin, B-cell lympoma-2 (BCL2) and proliferating cell nuclear antigen (PCNA). In vivo, knockdown of CD36 or Nogo-B in E0771 cells reduced its tumorigenic ability, which was further enhanced by knockdown of CD36 and Nogo-B simultaneously. Mechanistically, inhibition of CD36 and Nogo-B expression can decrease fatty acid binding protein 4 (FABP4) and fatty acid transport protein 4 (FATP4) expression. Moreover, overexpression of CD36 and Nogo-B-induced cell proliferation was attenuated by FABP4 siRNA, indicating that inhibition of CD36 and Nogo-B expression could inhibit the absorption and transport of fatty acids, thereby inhibiting the proliferation and migration of TNBC. Furthermore, inhibition of CD36 and Nogo-B expression activated the P53-P21-Rb signaling pathway which contributed to the CD36 and Nogo-B-inhibited proliferation and migration of TNBC. Taken together, the results suggest that inhibition of CD36 and Nogo-B can reduce the proliferation and migration of TNBC, which provides new targets for the development of drugs against TNBC.

SILAC proteomics based on 3D cell spheroids unveils the role of RAC2 in regulating the crosstalk between triple-negative breast cancer cells and tumor-associated macrophages

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and is characterized by a high infiltration of tumor-associated macrophages (TAMs). TAMs contribute significantly to tumor progression by intricately interacting with tumor cells. Deeply investigating the interaction between TNBC cells and TAMs is of great importance for finding potential biomarkers and developing novel therapeutic strategies to further improve the clinical outcomes of TNBC patients. In this study, we confirmed the interplay using both 3D and 2D co-culture models. The stable-isotype labeling by amino acids in cell culture (SILAC)-based quantitative proteomics was conducted on 3D cell spheroids containing TNBC cells and macrophages to identify the potential candidate in regulating the crosstalk between TNBC and TAMs. Ras-related C3 botulinum toxin substrate 2 (RAC2) was identified as a potential molecule for further exploration, given its high expression in TNBC and positive correlation with M2 macrophage infiltration. The suppression of RAC2 inhibited TNBC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro. Meanwhile, knocking down RAC2 in TNBC cells impaired macrophage recruitment and M2 polarization. Mechanistically, RAC2 exerted its roles in TNBC cells and TAMs by regulating the activation of P65 NF-κB and P38 MAPK, while TAMs further elevated RAC2 expression and P65 NF-κB activation by secreting soluble mediators including IL-10. These findings highlight the significance of RAC2 as a crucial molecule in the crosstalk between TNBC and TAMs, suggesting it could be a promising therapeutic target in TNBC.