Promotes Breast Cancer Cell Metastasis Research Articles

Oral bacterium Streptococcus mutans promotes tumor metastasis through thrombosis formation.

Thrombosis is a well-known cardiovascular disease (CVD) complication that has caused death in many patients with cancer. Oral bacteria have been reported to contribute to systemic diseases, including CVDs, and tumor metastasis. However, whether oral bacteria-induced thrombosis induces tumor metastasis remains poorly understood. In this study, the cariogenic oral bacterium Streptococcus mutans was used to examine thrombosis invitro and invivo. Investigation of tumor metastasis to the lungs was undertaken by intravenous S. mutans implantation using a murine breast cancer metastasis model. The results indicated that platelet activation, aggregation, and coagulation were significantly altered in S. mutans-stimulated endothelial cells (ECs), with elevated neutrophil migration, thereby inducing thrombosis formation. Streptococcus mutans stimulation significantly enhances platelet and tumor cell adhesion to the inflamed ECs. Furthermore, S. mutans-induced pulmonary thrombosis promotes breast cancer cell metastasis to the lungs invivo, which can be reduced by using aspirin, an antiplatelet drug. Our findings indicate that oral bacteria promote tumor metastasis through thrombosis formation. Oral health management is important to prevent CVDs, tumor metastasis, and their associated death.

Small peptide LINC00511-133aa encoded by LINC00511 regulates breast cancer cell invasion and stemness through the Wnt/β-catenin pathway

LINC00511 is an long non-coding RNA (lncRNA) of ncRNAs,This study aimed to investigate whether the lncRNA LINC00511 could encode a small peptide, LINC00511-133aa, and whether this peptide could promote breast cancer cell metastasis and stemness by activating the wnt/β-catenin pathway. The LINC00511-133aa coding sequence vector and control vector were transfected into MCF-7 and MDA-MB-231 breast cancer cells, with subsequent assessment of peptide expression using PCR, western blotting, and immunofluorescence assays. Cell proliferation, invasion, and apoptosis were evaluated using CCK8, apoptotic, wound healing, and transwell invasion assays, while the characteristic changes of tumor stem cells were detected through sphere-forming assay and western blot analyses of the stemness markers Oct4, Nanog, and SOX2. Results showed that LINC00511-133aa was indeed encoded by LINC00511 and promoted the invasiveness and stemness of breast cancer cells while limiting apoptosis by modulating the expression levels of wnt/β-catenin pathway-related proteins Bax, c-myc, and CyclinD1, as well as facilitating β-catenin protein entry into the nucleus. This study provides evidence for the potential involvement of lncRNA LINC00511 and its peptide product in breast cancer progression via the regulation of the wnt/β-catenin pathway.

SIPA1 Regulates LINC01615 to Promote Metastasis in Triple-Negative Breast Cancer.

Simple SummaryBreast cancer is a malignant tumor that often endangers women. After undergoing surgery and supplementary chemotherapy, however, tumor recurrence has not been well researched. The primary cause is high metastatic rates. Hence, bioinformatic and functional analyses were performed to indicate the effect of LINC01615 on breast cancer. We revealed that LINC01615 is regulated by the transcription factor SIPA1 in promoting breast cancer cell malignancy.Long non-coding RNAs (lncRNAs) are reported to play an important regulatory effect in carcinogenesis and malignancy. We found by high-throughput sequencing that LINC01615 is upregulated in breast cancer patients and reduces patients’ overall survival. In vivo and in vitro experiments, we clarified that overexpression of LINC01615 can promote breast cancer cell metastasis ability. The expression of LINC01615 is regulated by the transcriptional activator SIPA1, thereby promoting carcinogenesis in breast cancer cells. Our research clarified that LINC01615 can act as an oncogenic factor in promoting the development of breast cancer.

The oral bacterium Streptococcus mutans promotes tumor metastasis by inducing vascular inflammation.

Recent studies have demonstrated a relationship between oral bacteria and systemic inflammation. Endothelial cells (ECs), which line blood vessels, control the opening and closing of the vascular barrier and contribute to hematogenous metastasis; however, the role of oral bacteria-induced vascular inflammation in tumor metastasis remains unclear. In this study, we examined the phenotypic changes in vascular ECs following Streptococcus mutans (S. mutans) stimulation in vitro and in vivo. The expression of molecules associated with vascular inflammation and barrier-associated adhesion was analyzed. Tumor metastasis was evaluated after intravenous injection of S. mutans in murine breast cancer hematogenous metastasis model. The results indicated that S. mutans invaded the ECs accompanied by inflammation and NF-κB activation. S. mutans exposure potentially disrupts endothelial integrity by decreasing vascular endothelial (VE)-cadherin expression. The migration and adhesion of tumor cells were enhanced in S. mutans-stimulated ECs. Furthermore, S. mutans-induced lung vascular inflammation promoted breast cancer cell metastasis to the lungs in vivo. The results indicate that oral bacteria promote tumor metastasis through vascular inflammation and the disruption of vascular barrier function. Improving oral hygiene in patients with cancer is of great significance in preventing postoperative pneumonia and tumor metastasis.

Platinum nanoparticles promote breast cancer cell metastasis by disrupting endothelial barrier and inducing intravasation and extravasation

Platinum nanoparticles promote breast cancer cell metastasis by disrupting endothelial barrier and inducing intravasation and extravasation

O-GlcNAcylation of Blimp-1 in Lymphocytes Inhibits Its Transcriptional Function and Is Associated with Migration and Invasion of Breast Cancer Cells.

This study reveals a new mechanism by which the lymphatic system promotes breast cancer cell metastasis.

Dexamethasone enhances the lung metastasis of breast cancer via a PI3K-SGK1-CTGF pathway

Dexamethasone (Dex), as a pretreatment agent, is widely used to attenuate the side effects of chemotherapy in breast cancer treatment. However, whether and how Dex affects breast cancer metastasis remain to be furtherly understood. In this study, we established several mouse breast cancer metastatic models to study the effect of Dex in vitro and in vivo. Transwell, Western Blot and RNA interference were applied to study the molecular mechanism of Dex in promoting breast cancer cell migration. Meanwhile, the effect of Dex on lung metastasis of breast cancer in Dex combined with PTX chemotherapy was discussed. Our results confirmed that Dex could promote breast cancer cell metastasis both in vitro and in vivo. Mechanistic studies revealed that this pro-metastatic effect of Dex was mediated by the GR-PI3K-SGK1-CTGF pathway in tumor cells. Ligation of Dex and glucocorticoid receptor (GR) on tumor cells activated the PI3K signaling pathway and upregulated serum glucocorticoid-inducible kinase 1 (SGK1) expression, and then increased the expression of connective tissue growth factor (CTGF) through Nedd4l-Smad2. Moreover, Dex was the leading factor for lung metastasis in a standard regimen for breast cancer treatment with paclitaxel and Dex. Importantly, targeting SGK1 with the inhibitor GSK650394 remarkably reduced lung metastasis in this regimen. Our present data provide new insights into Dex-induced breast cancer metastasis and indicate that SGK1 could be a candidate target for the treatment of breast cancer metastasis.

MiR-934 promotes breast cancer metastasis by regulation of PTEN and epithelial–mesenchymal transition

Breast cancer (BC) is the most commonly diagnosed malignancy and the leading cause of cancer-related mortality among females. Over 90 % of the cases of death in BC patients are attributed to tumor cell metastasis. Therefore, it is urgently needed to investigate the molecular mechanisms of BC metastasis. The expression of miRNA in BC was evaluated by qRT-PCR and bioinformatics analysis. Clone formation, EdU assays, and subcutaneous xenograft model were used to test the growth of BC cells. Wound healing, transwell assays, and lung-metastasis model were used to explore the effect of miR-934 knockdown on cell metastasis. The miR-934 targets in BC were identified through bioinformatics analysis and luciferase reporter assays. The expression of protein was tested by western blot. The binding of mRNA and RNA-binding-protein was verified using RIP assays. miR-934 expression was significantly elevated in BC tissues, especially in those with lymph node metastasis and associated with poor patient prognosis. Experiments in vitro and in vivo showed that that upregulated miR-934 was not necessarily required for the growth of BC cells. However, miR-934 knockdown significantly inhibited the migration and invasion abilities of BC cells. Moreover, PTEN as identified as the direct target of miR-934 in BC, and miR-934 could promote BC cell metastasis by regulation of PTEN and epithelial–mesenchymal transition (EMT). Our results suggested that targeting miR-934 may be a practical treatment for BC cell metastasis.

Baicalin inhibits the TGF-β1/p-Smad3 pathway to suppress epithelial-mesenchymal transition-induced metastasis in breast cancer.

TGF-β1 is an epithelial-mesenchymal transition (EMT)-inducing factor that is critical in tumor progression. However, whether the effect of TGF-β1 on breast cancer is through the EMT pathway remains to be determined, and drug development based on this mechanism needs to be improved. Results of this study showed that TGF-β1 dysregulation significantly correlated with the expression levels of EMT-associated markers and transcriptional factors. Exogenous expression of TGF-β1 promoted breast cancer cell metastasis and EMT progression. In addition, direct binding of baicalin to TGF-β1 caused its inactivation, which subsequently blocked signal transduction and inhibited breast cancer cell metastasis. In vivo experiment results further invalidated the inhibitory effect of baicalin on TGF-β1-induced tumor metastasis. These results suggest that baicalin, an active ingredient used in traditional Chinese medicine, exhibits a potential therapeutic effect on breast cancer metastasis by regulating TGF-β1-dependent EMT progression.

ATXN3 promotes breast cancer metastasis by deubiquitinating KLF4.

Krüppel-like factor 4 (KLF4) is an important transcription factor implicated in a variety of essential cellular processes. Aberrant KLF4 expression is closely related to tumourigenesis and tumour progression. The rapid turnover of the KLF4 protein indicates an important role for the posttranslational modifications (PTMs) of KLF4. To date, E3 ligases mediating KLF4 ubiquitination have been widely reported, yet the deubiquitinating mechanism of KLF4 remains largely unknown. We screened a library of 65 deubiquitinating enzymes and identified ATXN3 as a deubiquitinating enzyme of KLF4. Subsequent immunoprecipitation assays confirmed that ATXN3 bound to KLF4, mediating the deubiquitination and stabilization of KLF4 protein levels. Furthermore, we demonstrated that ATXN3 promoted breast cancer cell metastasis via KLF4 in vitro and in vivo. Finally, the protein expression analysis of human breast cancer specimens demonstrated that ATXN3 significantly correlated with KLF4. High ATXN3/KLF4 expression was associated with a poor prognosis in breast cancer patients. Collectively, we identified ATXN3 as a novel deubiquitinating enzyme of KLF4, providing a new explanation for breast cancer metastasis, and proposed ATXN3 as a potential target for breast cancer metastasis treatment.

MicroRNA-4472 Promotes Tumor Proliferation and Aggressiveness in Breast Cancer by Targeting RGMA and Inducing EMT

BackgroundBreast cancer is the most common cause of cancer-related death in women worldwide. MicroRNA (miRNA) ectopic expression has been reported to be involved in the regulation of gene expression in breast cancer. We screened several differentially expressed miRNAs associated with breast cancer chemoresistance, growth, and metastasis using a miRNA microarray. Increased expression of miR-4472 has been associated with larger breast tumors and chemoresistance. However, the biologic function of miR-4472 and its molecular mechanisms in cancer progression have not yet been reported. Materials and MethodsReal-time quantitative polymerase chain reaction was used to measure the expression of miR-4472 in breast cancer tissue and cell lines. The biologic functions of miR-4472 and its target gene were explored using Transwell, cell proliferation, and flow cytometry assays. Bioinformatics tools, dual-luciferase reporter assays, and Western blot were used to identify the target genes of miR-4472. Western blot was used to explain the participation of miR-4472 and target gene in epithelial-to-mesenchymal transition. ResultsmiR-4472 was significantly upregulated in highly metastatic breast cancer tissues, and its expression was positively associated with larger tumor size and advanced pTNM stage. miR-4472 promoted breast cancer cell metastasis and growth. Repulsive guidance molecule A (RGMA) was a direct target gene of miR-4472. RGMA was identified as a suppressor in cancer metastasis. miR-4472 downregulated expression of RGMA and promoted epithelial-to-mesenchymal transition by suppressing E-cadherin and initiating vimentin, β-catenin, and Slug. ConclusionsmiR-4472 contributes to the progression of breast cancer by regulating RGMA expression and inducing epithelial-to-mesenchymal transition, indicating that miR-4472/RGMA might serve as a therapeutic target for breast cancer.

The relationship of lncRNA NR2F1 and breast cancer angiogenesis via IL-8/lncRNA NR2F1/miR-200s/IL-8 loop.

e12573 Background: Angiogenesis is key for metastasis and predicts a poor prognosis in breast cancer. Among the pro-angiogenic factors, interleukin-8 (IL-8) could be secreted by tumor cells mediated by microRNA-200 family (miR-200s). Long non-coding RNA (LncRNA), was reported to absorb microRNA to play multiple roles in various diseases including breast cancer. Our preliminary results recognized lncRNA NR2F1 through Agilent Human LncRNA array from breast cancer cells overexpressing IL-8. However, the relationship between LncRNA NR2F1 and breast cancer angiogenesis remains unknown. Methods: Breast cancer cell migration, invasion, proliferation and angiogenesis were assessed by Transwell, CCK8, tube formation, and wound healing assays. The expression of LncRNA NR2F1, miR-200s and IL-8 were detected by qPCR, Western blotting and ELISA. Breast cancer metastasis and angiogenesis in vivo were measured in a zebrafish model. Results: We found that the basal expression of lncRNA NR2F1 is higher in breast cancer cell lines than it in normal cells. In vitro, lncRNA NR2F1 induced breast cancer migration, invasion, and proliferation. Meanwhile, lncRNA NR2F1 promoted human umbilical vascular endothelial cell (HUVEC) proliferation, tube formation, and migration both via breast cancer conditioned medium and via direct HUVEC transfection. In the zebrafish model, lncRNA NR2F1 promoted breast cancer cell metastasis and neo-angiogenesis. Further study disclosed that lncRNA NR2F1 downregulated the expression of miR-200s, which in turn upregulated the expression of IL-8 in breast cancer cells. Conclusions: Our findings suggest that LncRNA NR2F1, as a potential promoter of breast cancer, may induce breast cancer angiogenesis through IL-8/lncRNA NR2F1/miR-200s/IL-8 loop.

Lysophosphatidic acid receptor 2 regulate expression of hypoxia inducible factor-1α to influence metastasis and invasion breast cancer cell

Objective To research the influence of breast cancer cell metastasis and invasion for lysophosphatidic acid receptor2 (LPAR2) regulate expression of hypoxia inducible factor-1α (HIF-1α). Methods Small interfering RNA (siRNA) and plasmid transfection was used to regulate the expression of LPAR2 and HIF-1α in michigan cancer foundation-7 (MCF-7) cells. Real-time polymerase chain reaction (PCR) and Western blotting were used to detected the expression of LPAR2 mRNA and protein. Transwell assays were conduct to study the migration and invsaion of MCF-7 cells. Results The capacity of metastasis and invasion was increased in transfected MCF-7 cells with high expressed LPAR2 (P=0.000). At the same time, the capacity of metastasis and invasion was increased in transfected MCF-7 cells with high expressed HIF-1α and LPAR2 could regulate the expression of HIF-1α. Conclusion High expression of LPAR2 and HIF-1α promote metastasis and invasion of breast cancer cells. LPAR2 was upstream molecule to regulate HIF-1α expression. LPAR2 and HIF-1α have the potential of breast cancer therapy target. Key words: Lysophosphatidic acid receptor2; Hypoxia inducible factor-1α; Breast cancer; Metastasis and invasion

G1P3 (IFI6), a mitochondrial localised antiapoptotic protein, promotes metastatic potential of breast cancer cells through mtROS

BackgroundRedox deregulations are ubiquitous in cancer cells. However, the role of mitochondrial redox deregulation in metastasis remains unclear. In breast cancer, upregulation of mitochondrial antiapoptotic protein G1P3 (IFI6) was associated with poor distance metastasis-free survival (DMFS). Therefore, we tested the hypothesis that G1P3-induced mitochondrial redox deregulation confers metastatic potentials in breast cancer cells.MethodsCell migration and invasion assays; confocal and immunofluorescence microscopy; and Illumina HumanHT-12 BeadChip to assess gene expression.ResultsConsequent to its localisation on inner-mitochondrial membrane, mtROS were higher in G1P3-expressing cells (MCF-7G1P3). G1P3-overexpressing cells migrated and invaded faster than the vector controls with increased number of filopodia and F-actin bundles (p ≤ 0.05). mtROS suppression with H2O2 scavengers and mitochondrial-specific antioxidants significantly decreased migratory structures and reversed G1P3-induced migration and invasion (p ≤ 0.05). Knocking down G1P3 decreased both migration and migratory structures in MCF-7G1P3 cells. Moreover, gene networks involved in redox regulation, metastasis and actin remodelling were upregulated in MCF-7G1P3 cells.ConclusionsG1P3-induced mtROS have a direct role in migratory structure formation and nuclear gene expression to promote breast cancer cell metastasis. Therefore, interrupting mitochondrial functions of G1P3 may improve clinical outcomes in breast cancer patients.

Long noncoding RNA LINP1 acts as an oncogene and promotes chemoresistance in breast cancer

ABSTRACTRecent studies have shown that long non-coding RNAs (lncRNAs) are involved in a number of biological processes; however, further study is still warranted to comprehensively reveal their functions. In this study, we showed that the lncRNA in non-homologous end joining (NHEJ) pathway 1 (LINP1) was related to breast cancer cell proliferation, metastasis and chemoresistance. Loss- and gain-of function studies were used to assess the role of LINP1 in promoting breast cancer progression. LINP1 knockdown mitigated breast cancer cell growth by inducing G1-phase cell cycle arrest and apoptosis. LINP1 also promoted breast cancer cell metastasis and influenced the expression of epithelial-mesenchymal transition-related markers. We identified p53 as a regulator of LINP1, and LINP1 overexpression could restore the metastatic effects of p53. Furthermore, LINP1 was upregulated in doxorubicin- and 5-fluorouracil-resistant cells and induced chemoresistance. We also observed that LINP1 enrichment played a critical functional role in chemoresistance by inhibiting chemotherapeutics-induced apoptosis. Moreover, LINP1 in tumors was associated with lower overall survival and disease-free survival. In conclusion, LINP1 may serve as a potential oncogene and chemoresistance-related regulator of breast cancer cells, suggesting that LINP1 might be a potent therapeutic target and might reduce chemoresistance in breast cancer.

Doxycycline inhibits breast cancer EMT and metastasis through PAR-1/NF-κB/miR-17/E-cadherin pathway.

Doxycycline displays high efficiency for cancer therapy. However, the molecular mechanism is poorly understood. In our previous study, doxycycline was found to suppress tumor progression by directly targeting proteinase-activated receptor 1 (PAR1). In this study, microRNAs were found to be involved in PAR1-mediated anti-tumor effects of doxycycline. Among these miRNAs, miR-17 was found to promote breast cancer cell metastasis both in vivo and in vitro. Moreover, miR-17 could reverse partial doxycycline inhibition effects on breast cancer. Employing luciferase and chromatin immunoprecipitation assays, nuclear factor-kappaB (NF-κB) was found to bind miR-17 promoters. Furthermore, E-cadherin was identified as the target gene of miR-17. These results showed that miR-17 can resist the inhibitory effects of doxycycline on breast cancer epithelial–mesenchymal transformation (EMT) by targeting E-cadherin.

SIRT7 antagonizes TGF-\u03b2 signaling and inhibits breast cancer metastasis

Distant metastasis is the main cause of breast cancer-related death; however, effective therapeutic strategies targeting metastasis are still scarce. This is largely attributable to the spatiotemporal intratumor heterogeneity during metastasis. Here we show that protein deacetylase SIRT7 is significantly downregulated in breast cancer lung metastases in human and mice, and predicts metastasis-free survival. SIRT7 deficiency promotes breast cancer cell metastasis, while temporal expression of Sirt7 inhibits metastasis in polyomavirus middle T antigen breast cancer model. Mechanistically, SIRT7 deacetylates and promotes SMAD4 degradation mediated by β-TrCP1, and SIRT7 deficiency activates transforming growth factor-β signaling and enhances epithelial-to-mesenchymal transition. Significantly, resveratrol activates SIRT7 deacetylase activity, inhibits breast cancer lung metastases, and increases survival. Our data highlight SIRT7 as a modulator of transforming growth factor-β signaling and suppressor of breast cancer metastasis, meanwhile providing an effective anti-metastatic therapeutic strategy.

Geminin facilitates FoxO3 deacetylation to promote breast cancer cell metastasis.

Geminin expression is essential for embryonic development and the maintenance of chromosomal integrity. In spite of this protective role, geminin is also frequently overexpressed in human cancers and the molecular mechanisms underlying its role in tumor progression remain unclear. The histone deacetylase HDAC3 modulates transcription factors to activate or suppress transcription. Little is known about how HDAC3 specifies substrates for modulation among highly homologous transcription factor family members. Here, we have demonstrated that geminin selectively couples the transcription factor forkhead box O3 (FoxO3) to HDAC3, thereby specifically facilitating FoxO3 deacetylation. We determined that geminin-associated HDAC3 deacetylates FoxO3 to block its transcriptional activity, leading to downregulation of the downstream FoxO3 target Dicer, an RNase that suppresses metastasis. Breast cancer cells depleted of geminin or HDAC3 exhibited poor metastatic potential that was attributed to reduced suppression of the FoxO3-Dicer axis. Moreover, elevated levels of geminin, HDAC3, or both together with decreased FoxO3 acetylation and reduced Dicer expression were detected in aggressive human breast cancer specimens. These results underscore a prominent role for geminin in promoting breast cancer metastasis via the enzyme-substrate-coupling mechanism in HDAC3-FoxO3 complex formation.

Aberrant low expression of p85\u03b1 in stromal fibroblasts promotes breast cancer cell metastasis through exosome-mediated paracrine Wnt10b

P85α, which acts as a tumour suppressor, is frequently found to be downregulated in various human cancers. However, the role of p85α in the tumour microenvironment is unknown. Here, we report that aberrantly low expression of p85α in breast cancer stroma is clinically relevant to breast cancer disease progression. Stromal fibroblasts can acquire the hallmarks of cancer-associated fibroblasts (CAFs) as a result of the loss of p85α expression. Paracrine Wnt10b from p85α-deficient fibroblasts can promote cancer progression via epithelial-to-mesenchymal transition (EMT) induced by the canonical Wnt pathway. Moreover, exosomes have a key role in paracrine Wnt10b transport from fibroblasts to breast cancer epithelial cells. Our results reveal that p85α expression in stromal fibroblasts haves a crucial role in regulating breast cancer tumourigenesis and progression by modifying stromal–epithelial crosstalk and remodelling the tumour microenvironment. Therefore, p85α can function as a tumour suppressor and represent a new candidate for diagnosis, prognosis and targeted therapy.

MicroRNA-200c/141 upregulates SerpinB2 to promote breast cancer cell metastasis and reduce patient survival.

The microRNA-200 (miR-200) family is associated with tumor metastasis and poor patient prognosis. We found that miR-200c/141 cluster overexpression upregulated SerpinB2 in the MDA-MB-231 triple-negative (TN) breast cancer cell line. We observed transcription factor (c-Jun, c-Fos, and FosB) upregulation, nuclear localization of c-Jun, and increased SerpinB2 promoter-directed chloramphenicol acetyltransferase activity in miR-200c/141 cluster-overexpressing cells relative to controls. Additionally, miR-124a and miR-26b, which directly target SepinB2, were downregulated compared to controls. In mouse xenograft models, miR-200c/141 cluster overexpression promoted lymph node and lung metastasis, and siRNA-mediated SerpinB2 knockdown decreased lung metastasis, suggesting that SerpinB2 mediates miR-200c/141-induced lung metastasis. We also explored the clinical significance of SerpinB2 protein status through analysis of primary breast tumor samples and The Cancer Genome Atlas (TCGA) data. High SerpinB2 levels were associated with reduced survival and increased lymph node metastasis in breast cancer patients. SerpinB2 was overexpressed in the TN breast cancer subtype as compared to the luminal subtype. The present study demonstrates that SerpinB2 promotes miR-200c/141 cluster overexpression-induced breast cancer cell metastasis, and SerpinB2 overexpression correlates with increased metastatic potential and unfavorable outcomes in breast cancer patients. SerpinB2 may be a useful biomarker for assessing metastasis risk in breast cancer patients.