MiR-4319 Suppress the Malignancy of Triple-Negative Breast Cancer by Regulating Self-Renewal and Tumorigenesis of Stem Cells

Background/Aims: High levels of cancer stem cells (CSCs) in patients with triple-negative breast cancer (TNBC) correlate with risk of poor clinical outcome and possibly contribute to chemoresistance and metastasis in patients with highly malignant TNBC. Aberrant microRNA expression is associated with the dysfunction of self-renewal and proliferation in cancer stem cells, while there is little information about the TNBC-specific microRNAs in regulating CSC ability. Methods: Solexa deep sequencing was performed to detect the expression levels of TNBC or non-TNBC stem cells (CSCs) microRNAs. Mammosphere formation assay, qRT-PCR and the xenograft model in nude mice were performed. Bioinformatic analysis and microarray were used to select the target gene, and luciferase reporter assays were used to confirm the binding sites. Results: Solexa sequencing data exhibited differential expression of 193 microRNAs between TNBC and non-TNBC stem cells. The gene ontology analysis and pathways analyses showed that genes were involved in the maintenance of stemness. MiR-4319 could suppress the self-renewal and formation of tumorspheres in TNBC CSCs through E2F2, and also inhibited tumor initiation and metastasis in vivo. Moreover, increased E2F2 could reverse the effect of miR-4319 on the self-renewal in TNBC CSCs. Conclusions: MiR-4319 suppresses the malignancy of TNBC by regulating self-renewal and tumorigenesis of stem cells and might be a remarkable prognostic factor or therapeutic target for patients with TNBC.

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Effects of Cancer Stem Cells in Triple-Negative Breast Cancer and Brain Metastasis: Challenges and Solutions

Cancers ◽

10.3390/cancers12082122 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2122

Author(s):

Kha-Liang Lee ◽

Gao Chen ◽

Tai-Yuan Chen ◽

Yung-Che Kuo ◽

Yu-Kai Su

Keyword(s):

Breast Cancer ◽

Stem Cells ◽

Cancer Stem Cells ◽

Brain Metastasis ◽

Triple Negative Breast Cancer ◽

Triple Negative ◽

Treatment Success ◽

Xenograft Model ◽

Disease Heterogeneity ◽

The Brain

A higher propensity of developing brain metastasis exists in triple-negative breast cancer (TNBC). Upon comparing the metastatic patterns of all breast cancer subtypes, patients with TNBC exhibited increased risks of the brain being the initial metastatic site, early brain metastasis development, and shortest brain metastasis-related survival. Notably, the development of brain metastasis differs from that at other sites owing to the brain-unique microvasculature (blood brain barrier (BBB)) and intracerebral microenvironment. Studies of brain metastases from TNBC have revealed the poorest treatment response, mostly because of the relatively backward strategies to target vast disease heterogeneity and poor brain efficacy. Moreover, TNBC is highly associated with the existence of cancer stem cells (CSCs), which contribute to circulating cancer cell survival before BBB extravasation, evasion from immune surveillance, and plasticity in adaptation to the brain-specific microenvironment. We summarized recent literature regarding molecules and pathways and reviewed the effects of CSC biology during the formation of brain metastasis in TNBC. Along with the concept of individualized cancer therapy, certain strategies, namely the patient-derived xenograft model to overcome the lack of treatment-relevant TNBC classification and techniques in BBB disruption to enhance brain efficacy has been proposed in the hope of achieving treatment success.

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Targeting Cancer Stem Cells in Triple-Negative Breast Cancer

Cancers ◽

10.3390/cancers11070965 ◽

2019 ◽

Vol 11 (7) ◽

pp. 965 ◽

Cited By ~ 30

Author(s):

Park ◽

Choi ◽

Nam

Keyword(s):

Breast Cancer ◽

Stem Cells ◽

Cancer Stem Cells ◽

Triple Negative Breast Cancer ◽

Molecular Mechanisms ◽

Triple Negative ◽

Therapy Resistance ◽

Therapeutic Effects ◽

Self Renewal ◽

The Future

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer that lacks targeted therapy options, and patients diagnosed with TNBC have poorer outcomes than patients with other breast cancer subtypes. Emerging evidence suggests that breast cancer stem cells (BCSCs), which have tumor-initiating potential and possess self-renewal capacity, may be responsible for this poor outcome by promoting therapy resistance, metastasis, and recurrence. TNBC cells have been consistently reported to display cancer stem cell (CSC) signatures at functional, molecular, and transcriptional levels. In recent decades, CSC-targeting strategies have shown therapeutic effects on TNBC in multiple preclinical studies, and some of these strategies are currently being evaluated in clinical trials. Therefore, understanding CSC biology in TNBC has the potential to guide the discovery of novel therapeutic agents in the future. In this review, we focus on the self-renewal signaling pathways (SRSPs) that are aberrantly activated in TNBC cells and discuss the specific signaling components that are involved in the tumor-initiating potential of TNBC cells. Additionally, we describe the molecular mechanisms shared by both TNBC cells and CSCs, including metabolic plasticity, which enables TNBC cells to switch between metabolic pathways according to substrate availability to meet the energetic and biosynthetic demands for rapid growth and survival under harsh conditions. We highlight CSCs as potential key regulators driving the aggressiveness of TNBC. Thus, the manipulation of CSCs in TNBC can be a targeted therapeutic strategy for TNBC in the future.

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Chemotherapeutic stress influences epithelial-mesenchymal transition and stemness in cancer stem cells of triple‐negative breast cancer

10.1055/s-0040-1717860 ◽

2020 ◽

Author(s):

X Li ◽

J Strietz ◽

A Bleilevens ◽

E Stickeler ◽

J Maurer

Keyword(s):

Breast Cancer ◽

Stem Cells ◽

Cancer Stem Cells ◽

Triple Negative Breast Cancer ◽

Triple Negative ◽

Epithelial Mesenchymal Transition ◽

Mesenchymal Transition ◽

Stress Influences

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A novel humanized Frizzled-7-targeting antibody enhances antitumor effects of Bevacizumab against triple-negative breast cancer via blocking Wnt/β-catenin signaling pathway

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-020-01800-x ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Wei Xie ◽

Huijie Zhao ◽

Fengxian Wang ◽

Yiyun Wang ◽

Yuan He ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative Breast Cancer ◽

Molecular Mechanisms ◽

Near Infrared ◽

Triple Negative ◽

Vasculogenic Mimicry ◽

Xenograft Model ◽

Luciferase Reporter ◽

Antitumor Effects ◽

Mouse Xenograft Model

Abstract Background Anti-angiogenic therapy has been widely applied to the clinical treatment of malignant tumors. However, the efficacy of such treatments has been called into question, especially in triple-negative breast cancer (TNBC). Bevacizumab, the first anti-angiogenic agent approved by FDA, actually increases invasive and metastatic properties of TNBC cells, resulting from the activation of Wnt/β-catenin signaling in response to hypoxia. As a critical receptor of Wnt/β-catenin signaling, Frizzled-7 (Fzd7) is aberrantly expressed in TNBC, indicating Fzd7 a potential target for developing drugs to be combined with anti-angiogenic agents. Methods Hybridoma technique and antibody humanization technique were utilized to generate a Fzd7-targeting antibody (SHH002-hu1). Biolayer interferometry (BLI) assay and near infrared (NIR) imaging were conducted to detect the affinity and targeting ability of SHH002-hu1. Next, whether SHH002-hu1 could suppress the invasion and migration of TNBC cells induced by Bevacizumab were validated, and the underlying molecular mechanisms were elucidated by luciferase reporter and western blot assays. The nude-mice transplanted TNBC models were established to assess the anti-TNBC activities of SHH002-hu1 when combined with Bevacizumab. Then, the effects on putative TNBC stem-like cells and Wnt/β-catenin signaling were evaluated by immunofluorescence (IF). Further, the tumor-initiating and self-renew capacity of TNBC cells were studied by secondary nude mouse xenograft model and sphere formation assay. In addition, the effects of SHH002-hu1 on the adaptation of TNBC cells to hypoxia were evaluated by the detection of vasculogenic mimicry (VM) and hypoxia-inducible factor-1α (HIF-1α) transcriptional activity. Results The novel humanized antibody targeting Fzd7 (SHH002-hu1) exhibited extremely high affinity with Fzd7, and specifically targeted to Fzd7+ cells and tumor tissues. SHH002-hu1 repressed invasion, migration and epithelial-mesenchymal cell transformation (EMT) of TNBC cells induced by Bevacizumab through abating Wnt/β-catenin signaling. SHH002-hu1 significantly enhanced the capacity of Bevacizumab to inhibit the growth of TNBC via reducing the subpopulation of putative TNBC stem-like cells, further attenuating Bevacizumab-enhanced tumor-initiating and self-renew capacity of TNBC cells. Moreover, SHH002-hu1 effectively restrained the adaptation of TNBC cells to hypoxia via disrupting Wnt/β-catenin signaling. Conclusion SHH002-hu1 significantly enhances the anti-TNBC capacity of Bevacizumab, and shows the potential of preventing TNBC recurrence, suggesting SHH002-hu1 a good candidate for the synergistic therapy together with Bevacizumab.

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