Effects of FSTL1 on cell proliferation in breast cancer cell line MDA‑MB‑231 and its brain metastatic variant MDA‑MB‑231‑BR

Differential expression of FSTL1 and its correlation with the pathological process of periodontitis

AIMS

This study aimed to elucidate the alterations in Follistatin-like protein 1 (FSTL1) and its association with the pathological process of periodontitis.

METHODS

This study included 48 patients with periodontitis and 42 healthy controls. The expression level of FSTL1 in the gingiva was determined by RT-qPCR, validated using the dataset GSE16134, and subsequently examined by western blotting. Bioinformatics analysis revealed a single-cell distribution of FSTL1, characteristic of angiogenesis and immune cell infiltration. The expression and distribution of FSTL1, vascular endothelial marker protein CD31 and myeloperoxidase (MPO), the indicator of neutrophil activity, were determined by immunohistochemistry (IHC). A series of correlation analyses was performed to determine the associations between FSTL1 and clinical parameters, including probing depth (PD) and clinical attachment loss (CAL), and their potential role in angiogenesis (CD31) and neutrophil infiltration (MPO).

RESULTS

FSTL1 was significantly upregulated in the gingiva of patients with periodontitis compared to their healthy counterparts. In addition, FSTL1 was positively correlated with the clinical parameters PD (r = .5971, p = .0005) and CAL (r = .6078, p = .0004). Bioinformatic analysis and IHC indicated that high FSTL1 expression was significantly correlated with angiogenesis and neutrophil infiltration in periodontitis. Moreover, receiver operating characteristic (ROC) analysis demonstrated that FSTL1 could serve as an independent indicator for evaluating the severity of periodontitis (area under the curve [AUC] = 0.9011, p < .0001).

CONCLUSION

This study demonstrated FSTL1 upregulation in periodontitis and its potential contribution to the disease via angiogenesis and neutrophil infiltration.

FSTL1: A double-edged sword in cancer development

Flolistatin-related protein 1 (FSTL1), a secreted glycoprotein that is involved in many physiological functions, has attracted much interest and has been implicated in a wide range of diseases, including heart diseases and inflammatory diseases. In recent years, the involvement of FSTL1 in cancer progression has been implicated and researched. FSTL1 plays a contradictory role in cancer, depending on the cancer type as well as the contents of the tumor microenvironment. As reviewed here, the structure and distribution of FSTL1 are first introduced. Subsequently, the expression and clinical significance of FSTL1 in various types of cancer as a tumor enhancer or inhibitor are addressed. Furthermore, we discuss the functional role of FSTL1 in various processes that involve tumor cell proliferation, metastasis, immune responses, stemness, cell apoptosis, and resistance to chemotherapy. FSTL1 expression is tightly controlled in cancer, and a multitude of cancer-related signaling cascades like TGF-β/BMP/Smad signaling, AKT, NF-κB, and Wnt-β-catenin signaling pathways are modulated by FSTL1. Finally, FSTL1 as a therapeutic target using monoclonal antibodies is stated. Herein, we review recent findings showing the double-edged characteristics and mechanisms of FSTL1 in cancer and elaborate on the current understanding of therapeutic approaches targeting FSTL1.

Follistatin-Like Proteins: Structure, Functions and Biomedical Importance

Main forms of cellular signal transmission are known to be autocrine and paracrine signaling. Several cells secrete messengers called autocrine or paracrine agents that can bind the corresponding receptors on the surface of the cells themselves or their microenvironment. Follistatin and follistatin-like proteins can be called one of the most important bifunctional messengers capable of displaying both autocrine and paracrine activity. Whilst they are not as diverse as protein hormones or protein kinases, there are only five types of proteins. However, unlike protein kinases, there are no minor proteins among them; each follistatin-like protein performs an important physiological function. These proteins are involved in a variety of signaling pathways and biological processes, having the ability to bind to receptors such as DIP2A, TLR4, BMP and some others. The activation or experimentally induced knockout of the protein-coding genes often leads to fatal consequences for individual cells and the whole body as follistatin-like proteins indirectly regulate the cell cycle, tissue differentiation, metabolic pathways, and participate in the transmission chains of the pro-inflammatory intracellular signal. Abnormal course of these processes can cause the development of oncology or apoptosis, programmed cell death. There is still no comprehensive understanding of the spectrum of mechanisms of action of follistatin-like proteins, so the systematization and study of their cellular functions and regulation is an important direction of modern molecular and cell biology. Therefore, this review focuses on follistatin-related proteins that affect multiple targets and have direct or indirect effects on cellular signaling pathways, as well as to characterize the directions of their practical application in the field of biomedicine.

FSTL1 promotes growth and metastasis in gastric cancer by activating AKT related pathway and predicts poor survival

Accumulating evidence on the role of Follistatin-like protein 1 (FSTL1) in tumorigenesis and cancer progression is conflicting. Nevertheless, the underlying mechanisms by which FSTL1 contributes to gastric cancer (GC) remain unknown. This study shows that FSTL1 was frequently upregulated in primary GC tissues and significantly correlated with infiltrating depth, lymph node metastasis, unfavorable tumor stage and poor prognosis of GC. Down or up-regulation of FSTL1 inhibited or increased, respectively, the proliferation by reducing apoptosis, clonogenicity, migration and invasion of GC cells in vitro. Moreover, the higher expression of FSTL1 promoted subcutaneous xenograft tumor growth and lung/liver tumor metastasis in vivo. Furthermore, we demonstrate that FSTL1 is involved in regulation of the AKT signaling through analyzing databases and experimental results. Mechanistic studies showed that FSTL1 promoted proliferation, migration and invasion in GC, at least partially, by activating AKT via regulating TLR4/CD14. In all, this study highlights the role of the FSTL1-TLR4/CD14-AKT axis, which provided novel insights into the mechanism of growth and metastasis in GC for the first time.

Follistatin-like 1 deficiency impairs T cell development to promote lung metastasis of triple negative breast cancer

Our study aims to detect the underlying mechanism of the suppressive effect of Follistatin-like 1 (FSTL1) on lung metastasis of triple negative breast cancer (TNBC). We found that FSTL1 had no effect on the proliferation and metastasis of 4T1 cells in vitro, while in the tumor-bearing Fstl1 heterozygous (Fstl1^+/-) mice, the number of anti-tumor T lymphocytes in the lung was significantly reduced with the increase in lung metastasis. Impaired development of T cells can cause dysfunction of adaptive immune system, which promotes cancer metastasis. Therefore the effect of FSTL1 on T cell development was further investigated. Lower population of T cells in periphery and decreased proliferation of CD4^- CD8^- double negative (DN) thymocytes and impairment development of T cells were found in Fstl1^+/- mice. Furthermore, high expression of FSTL1 in medullary thymus epithelial (mTEC) cells and decreased mRNA expression of inducible costimulator on activated T-cell ligand (Icosl) in mTEC^{sh Fstl1} were detected. Combining other studies that the generation of ICOSL by mTEC cells promotes CD4⁺ single positive (SP) thymocytes to produce IL-2, which promotes T cell development. Our results indicate FSTL1 deficiency in mTEC cells impairs T cell development to promote the lung metastasis of TNBC.

F-Box protein 4 inhibits progression of papillary thyroid cancer

OBJECTIVE

We aimed to investigate the role of F-Box protein 4 (FBXO4) in the progression of papillary thyroid cancer (PTC) and to reveal the underlying signaling pathways responsible for FBXO4 action in PTC.

METHODS

FBXO4 expression was evaluated in tissues from PTC patients as well as in cell lines. Overexpression of FBXO4 was re-introduced into PTC cell line B-CPAP, followed by analysis of cell migration, invasion, apoptosis and epithelial-mesenchymal transition (EMT) marker profile. An in vivo xenograft tumor mouse model was employed to address the role of FBXO4 in tumorigenesis as well.

RESULTS

Endogenous FBXO4 was downregulated in PTC patient tissues and cell lines. Upon re-introducing its expression, FBXO4 suppressed migration and invasion and induced apoptosis of PTC cells, as well as inhibited EMT. Using a xenograft tumor mouse model, the pro-apoptotic and anti-EMT functions of FBXO4 are also validated in vivo, resulting in considerably slowed tumor growth rate of inoculated FBXO4-expressing PTC cells.

CONCLUSION

Our results therefore propose the potential therapeutic value of FBXO4 in targeted treatments against PTC.

FSTL1 increases cisplatin sensitivity in epithelial ovarian cancer cells by inhibition of NF-κB pathway

OBJECTIVE

To investigate the effects of FSTL1-mediated NF-κB signaling pathway on cisplatin (DDP) sensitivity of EOC cells.

METHODS

FSTL1 expression was determined in epithelial ovarian cancer (EOC) tissues and corresponding adjacent tissues using immunohistochemistry. SKOV3 and SKOV3/DDP cells were transfected and grouped into Blank, Vector, and FSTL1 groups. The sensitivity and 50% inhibitory concentration (IC50) of cells treated with different concentrations of DDP were detected by MTT assay. SKOV3/DDP cells were treated with 20 μM DDP, followed by evaluation of cell proliferation, cell apoptosis and determination of NF-κB pathway-related proteins while SKOV3 cells without.

RESULTS

FSTL1 expression in EOC tissues and cells was significantly down-regulated, especially decreased in DDP-resistant EOC cells SKOV3/DDP. In SKOV3 cells and SKOV3/DDP cells, the cell viability was reduced and the DDP sensitivity was improved with the decreased IC50 after over-expressing FSTL1. Compared with Blank group, FSTL1 group had declined number of SKOV3 cell colonies and increased cell apoptosis, with obvious up-regulations of FSTL1, Bax/Bcl-2 and cleaved caspase-3 expression and the down-regulations of p-IκBα, p-p65 and survivin expression. Combination of up-regulation of FSTL1 and DDP treatment can also effectively reduce cell colony forming, increase cell apoptosis, and inhibit NF-κB pathway activity of SKOV3/DDP cells. Moreover, this combination can also significantly suppress the growth of subcutaneous xenograft tumors in nude mice.

CONCLUSION

FSTL1 may inhibit NF-κB signaling pathway to suppress the growth and promote the apoptosis of epithelial ovarian cancer cells, and thereby enhancing its DDP sensitivity.

Follistatin-like 1 (FSTL1) is a prognostic biomarker and correlated with immune cell infiltration in gastric cancer

Background

Follistatin-like 1 (FSTL1) plays a central role in the progression of tumor and tumor immunity. However, the effect of FSTL1 on the prognosis and immune infiltration of gastric cancer (GC) remains to be elucidated.

Methods

The expression of FSTL1 data was analyzed in Oncomine and TIMER databases. Analyses of clinical parameters and survival data were conducted by Kaplan-Meier plotter and immunohistochemistry. Western blot assay and real-time quantitative PCR (RT-qPCR) were used to analyze protein and mRNA expression, respectively. The correlations between FSTL1 and cancer immune infiltrates were analyzed by Tumor Immune Estimation Resource (TIME), Gene Expression Profiling Interactive Analysis (GEPIA), and LinkedOmics database.

Results

The expression of FSTL1 was significantly higher in GC tissues than in normal tissues, and bioinformatic analysis and immunohistochemistry (IHC) indicated that high FSTL1 expression significantly correlated with poor prognosis in GC. Moreover, FSTL1 was predicted as an independent prognostic factor in GC patients. Bioinformatics analysis results suggested that FSTL1 mainly involved in tumor progression and tumor immunity. And significant correlations were found between FSTL1 expression and immune cell infiltration in GC.

Conclusions

The study effectively revealed useful information about FSTL1 expression, prognostic values, potential functional networks, and impact of tumor immune infiltration in GC. In summary, FSTL1 can be used as a biomarker for prognosis and evaluating immune cell infiltration in GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-020-02070-9.

Developing Bioinspired Three-Dimensional Models of Brain Cancer to Evaluate Tumor-Homing Neural Stem Cell Therapy

Engineered neural stem cells (NSCs) have recently emerged as a promising therapy. Acting as a tumor-homing drug-delivery system, NSCs migrate through brain tissue to seek out primary and invasive tumor foci. NSCs can deliver therapeutic agents, such as TNFα-related apoptosis-inducing ligand, directly to the tumor and suppress glioblastoma (GBM) in murine models. While the mainstays for evaluating NSC migration and efficacy have been two-dimensional chemotaxis assays and mouse models, these low-throughput and small-scale systems limit our ability to implant and track these cells for human translation. To circumvent these challenges, we developed a three-dimensional culture system using a matrix of poly-l-lactic acid 6100 microfibers suspended in agar. These bioinspired brain matrices were used to model tumor growth, NSC migration, and efficacy of NSC therapy at small and human scale. Kinetic fluorescent imaging confirmed growth of tumors in both small and human-sized bioinspired brain matrix. Tumors proliferated 50-fold and 3-fold for GBM and human metastatic breast cancer, respectively, over 7 days. We next explored the impact of tumor location on NSC migration. When NSCs were implanted 2 mm lateral from the tumor foci, NSCs colocalized with the GBM within 7 days. In models of multifocal disease, NSCs were found to colocalize with multiple tumors, preferentially migrating to tumor foci closest to the site of NSC implantation. Lastly, therapeutic NSCs were implanted at increasing distances (0, 2, 5, or 10 mm) laterally from GBM foci to investigate the effects of distance on NSC efficacy. Serial imaging showed reduced fluorescence at tumor sites, implicating GBM apoptosis across all distances. NSCs coinjected with tumor induced a near-complete response in <10 days, while NSCs implanted 10 mm laterally from the tumor induced a near-complete response by day 30. Lastly, GBM foci were established in each hemisphere of the model and control or therapeutic NSCs were implanted adjacent to tumor cells in the right hemisphere. Kinetic imaging showed that NSC therapy attenuated progression of GBM foci, while GBM cells treated with control NSC expanded rapidly over 21 days. In conclusion, we developed a new bioinspired model that supports growth of human brain cancer cells and enables rapid tracking of NSC therapy. Impact statement Tumor-homing and tumor-killing-engineered neural stem cell (NSC) therapies have shown immense promise in both preclinical and clinical trials. However, as cell therapies continue to evolve, cost-effective and high-throughput screening assays are needed to assess the proliferation, migration, and efficacy of these cells. In this study, we developed a bioinspired brain matrix for the evaluation of engineered NSCs. Importantly, this matrix is easy to fabricate, scalable, and allows for sterile real-time, noninvasive imaging using our custom bioreactor. We then utilized the bioinspired brain matrix system to answer key questions around the tumor-homing migration and efficacy of engineered NSC therapies that are challenging to address with traditional models.

Single-Cell Mapping of Human Brain Cancer Reveals Tumor-Specific Instruction of Tissue-Invading Leukocytes

Brain malignancies can either originate from within the CNS (gliomas) or invade from other locations in the body (metastases). A highly immunosuppressive tumor microenvironment (TME) influences brain tumor outgrowth. Whether the TME is predominantly shaped by the CNS micromilieu or by the malignancy itself is unknown, as is the diversity, origin, and function of CNS tumor-associated macrophages (TAMs). Here, we have mapped the leukocyte landscape of brain tumors using high-dimensional single-cell profiling (CyTOF). The heterogeneous composition of tissue-resident and invading immune cells within the TME alone permitted a clear distinction between gliomas and brain metastases (BrM). The glioma TME presented predominantly with tissue-resident, reactive microglia, whereas tissue-invading leukocytes accumulated in BrM. Tissue-invading TAMs showed a distinctive signature trajectory, revealing tumor-driven instruction along with contrasting lymphocyte activation and exhaustion. Defining the specific immunological signature of brain tumors can facilitate the rational design of targeted immunotherapy strategies.

Hsa_circ_0011290 regulates proliferation, apoptosis and glycolytic phenotype in papillary thyroid cancer via miR-1252/ FSTL1 signal pathway

OBJECTIVE

Despite of previous report regarding the aberrant overexpression of hsa_circ_0011290 in thyroid cancer, the regulatory mechanism and mechanistic involvements of which were still elusive currently in papillary thyroid cancer (PTC). Here we set out to characterize expression status and functional contributions of hsa_circ_0011290 in this disease especially through mode-of-action of sponging RNA.

METHODS

Relative expression of hsa_circ_0011290, microRNA (miR)-1252 and FSTL1 was quantified by real-time polymerase chain reaction. Glucose metabolism was determined by examination of glucose uptake, lactate production and ATP contents. The regulatory effects of miR-1252 on both hsa_circ_0011290 and Follistatin Like 1 (FSTL1) were interrogated by luciferase reporter assay. Direct binding between miR-1252 with hsa_circ_0011290 and FSTL1 transcripts were analyzed by RNA pulldown assay. Protein levels of FSTL1 was examined by Western blots.

RESULTS

Aberrant over-expression of hsa_circ_0011290 was associated with advanced stage and unfavorable prognosis of PTC. Knockdown of hsa_circ_0011290 greatly inhibited cell viability, proliferation and stimulated cell apoptosis in PTC cells. Meanwhile, glucose metabolism was significantly switched with decreased glucose uptake and lactate production, and increased ATP contents. We identified miR-1252 as target miR of hsa_circ_0011290, and miR-1252 evidently inhibited expressions of both luciferase reporter and endogenous hsa_circ_0011290, and miR-1252 was negatively regulated by hsa_circ_0011290 vice versa. We further suggested that FSTL1 as direct target of miR-1252, and provided direct evidences in support of binding between miR-1252 with both hsa_circ_0011290 and FSTL1. Through sponging miR-1252, hsa_circ_0011290 was capable of positively modulate FSTL1 expression. Notably, inhibition of miR-1252 completely reversed phenotypic effects of hsa_circ_0011290 knockdown including cell viability, proliferation, apoptosis and glucose metabolisms.

CONCLUSION

Our study uncovered the oncogenic contributions of hsa_circ_0011290-miR-1252-FSTL1 in PTCs.

The glycoprotein follistatin-like 1 promotes brown adipose thermogenesis

OBJECTIVES

The thermogenic brown adipose tissue (BAT) has been proposed as a potential target to prevent or treat obesity and related metabolic diseases. BAT secretes adipokines to regulate the thermogenic program in an autocrine or paracrine manner. Follistatin-like 1 (FSTL1), a glycoprotein involved in adipogenesis and obesity, however, the function of FSTL1 in BAT thermogenesis and in the regulation of systemic energy homeostasis are not fully understood.

METHODS

Whole-body ablation Fstl1 heterozygous mice (Fstl1^+/-) and its littermates control were injected with CL316,243 to assess energy balance. A series of FSTL1 overexpression and knockdown experiments were carried out to evaluate its function in regulating thermogenic gene expression in brown adipocytes.

RESULTS

FSTL1 expression was induced upon BAT activation during cold challenge or β3-adrenergic activation. FSTL1 haploinsufficiency in mice led to reduced thermogenic gene expression, impaired BAT recruitment, and decreased heat production. FSTL1 cell-autonomously promoted the β3-adrenergic signaling, which was required to upregulate PPARγ and UCP1 in brown adipocytes. Furthermore, only glycosylated FSTL1 could be secreted from brown adipocytes to induce the β3-adrenergic activation.

CONCLUSIONS

Our results suggest FSTL1 as a novel stimulator of the β-adrenergic signaling and BAT thermogenesis.

FSTL1 enhances chemoresistance and maintains stemness in breast cancer cells via integrin β3/Wnt signaling under miR-137 regulation

FSTL1 is a protein coding gene associated with cell signaling pathway regulation and the progression of a variety of disorders. In this study, we hypothesized that FSTL1 increases oncogenesis in breast cancer by enhancing stemness and chemoresistance. RT-PCR and IHC revealed significantly higher FSTL1 mRNA and protein levels in TNBC than in non-TNBC specimens and in breast cancer cell lines. We then found that FSTL1 levels were significantly increased in chemoresistant cells. LIVE/DEAD, MTT cell viability and colony formation assays did in fact demonstrate that FSTL1 is required for CDDP and DOX chemoresistance in breast cancer cell lines. FSTL1 overexpression caused significant elevation of stem cell biomarkers, as well as breast cancer cell proliferation. To determine whether the Wnt/β-catenin signaling pathway is involved in the observed effects of FSTL1, we assessed levels of pathway target. TOP/FOP flash, colony formation, and tumor sphere formation assays indicated that FSTL1 activates Wnt/β-catenin signaling through integrin β3. We then sought to identify a microRNA (miRNA) that regulates FSTL1 activity. Luciferase assays demonstrated that miR-137 reduces FSTL1 mRNA and protein levels. Ultimately, our findings indicate that there is an miR-137/FSTL1/integrin β3/Wnt/β-catenin signaling axis in breast cancer cells that regulates stemness and chemoresistance.

Deficiency of Follistatin-Like Protein 1 Accelerates the Growth of Breast Cancer Cells at Lung Metastatic Sites

Purpose

Follistatin-like protein 1 (FSTL1) is a secreted glycoprotein that has been shown to play a role in various types of cancer. However, the clinical significance and function of FSTL1 in breast cancer have not been reported. We investigated the role of FSTL1 in breast cancer in this study.

Methods

Enzyme-linked immunosorbent assays, western blot analysis, and reverse transcription polymerase chain reaction were used to monitor the expression of FSTL1 in breast cancer tissue and in serum samples from breast cancer patients. We employed a 4T1 breast cancer model and Fstl1 ^+/- mice for in vivo studies. Hematoxylin and eosin staining, western blot analysis, and RNA sequencing were used to analyze the effect of FSTL1 on primary tumor growth and lung metastasis.

Results

We demonstrated that the expression of FSTL1 is reduced in both the breast cancer tissue and the serum of breast cancer patients. We showed that reduced levels of FSTL1 in serum correlate with elevated expression of Ki-67 and epidermal growth factor receptor (EGFR) in cancer tissues. Moreover, lowered expression of FSTL1 was associated with decreased survival in breast cancer patients. Experiments on the Fstl1 ^+/- mouse model established that FSTL1 deficiency had no effect on primary tumor growth, but increased the lung metastases of breast cancer cells, resulting in reduced survival of tumor-bearing mice. RNA sequencing found significantly reduced expression of Egln3 and increased expression of EGFR in Fstl1 ^+/- mice. Thus, our results suggest that FSTL1 may affect the expression of EGFR through Egln3, inhibiting the proliferation of breast cancer cells at lung metastatic sites.

Conclusion

In conclusion, we suggest a suppressor role of FSTL1 in breast cancer lung metastasis. Furthermore, FSTL1 may represent a potential prognostic biomarker and a candidate therapeutic target in breast cancer patients.

Follistatin-like 1 in development and human diseases

Follistatin-like 1 (FSTL1) is a secreted glycoprotein displaying expression changes during development and disease, among which cardiovascular disease, cancer, and arthritis. The cardioprotective role of FSTL1 has been intensively studied over the last years, though its mechanism of action remains elusive. FSTL1 is involved in multiple signaling pathways and biological processes, including vascularization and regulation of the immune response, a feature that complicates its study. Binding to the DIP2A, TLR4 and BMP receptors have been shown, but other molecular partners probably exist. During cancer progression and rheumatoid arthritis, controversial data have been reported with respect to the proliferative, apoptotic, migratory, and inflammatory effects of FSTL1. This controversy might reside in the extensive post-transcriptional regulation of FSTL1. The FSTL1 primary transcript also encodes for a microRNA (miR-198) in primates and multiple microRNA-binding sites are present in the 3'UTR. The switch between expression of the FSTL1 protein and miR-198 is an important regulator of tumour metastasis and wound healing. The glycosylation state of FSTL1 is a determinant of biological activity, in cardiomyocytes the glycosylated form promoting proliferation and the non-glycosylated working anti-apoptotic. Moreover, the glycosylation state shows differences between species and tissues which might underlie the differences observed in in vitro studies. Finally, regulation at the level of protein secretion has been described.

Oridonin inhibits VEGF-A-associated angiogenesis and epithelial-mesenchymal transition of breast cancer in vitro and in vivo

Metastasis is the primary cause of mortality in patients with breast cancer and lacks effective therapeutic agents. Oridonin, an active diterpenoid compound isolated from Rabdosia rubescens, was identified to be the most potent anti-tumor ingredient. However, the molecular mechanisms responsible for its anti-metastatic effects remain unclear. In the present study, oridonin significantly suppressed the migration, invasion and adhesion of MDA-MB-231 and 4T1 breast cancer cells, and inhibited tube formation of human umbilical vein endothelial cells in a dose-dependent manner. The expression levels of epithelial-mesenchymal transition (EMT)-associated marker and the hypoxia inducible factor 1α (HIF-1α)/vascular endothelium growth factor (VEGF) signaling pathway mRNA and proteins were determined by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively in vitro. The results demonstrated that oridonin effectively inhibited EMT as demonstrated by the significant increases in the expression levels of E-cadherin, and decreased expression of N-cadherin, Vimentin and Snail. In addition, oridonin exerted its anti-angiogenesis activity through significantly decreasing HIF-1α, VEGF-A and VEGF receptor-2 protein expression. Furthermore, oridonin was demonstrated to decrease the micro-vessel density as evidenced by the decreased expression of cluster of differentiation 31, a marker for neovasculature. In brief, oridonin inhibits tumor cell migration, invasion and adhesion, as well as tumor angiogenesis, which are mediated by suppressing EMT and the HIF-1α/VEGF signaling pathway. The results of the present study suggest that oridonin may be a promising anti-metastatic agent in breast cancer treatment.