Dataset Information

MiR-623 Targets Metalloproteinase-1 and Attenuates Extravasation of Brain Metastatic Triple-Negative Breast Cancer Cells.

ABSTRACT:

Background

Most breast cancer-related deaths result from metastasis. Understanding the molecular basis of metastasis is needed for the development of effective targeted and preventive strategies. Matrix metalloproteinase-1 (MMP1) plays an important role in brain metastasis (BM) of triple-negative breast cancer (TNBC) by promoting extravasation of cancer cells across the brain endothelium (BE). MMP1 expression is controlled by endogenous microRNAs. Preliminary bioinformatics analysis has revealed that miR-623, known to target the 3'UTR of MMP1, is significantly downregulated in brain metastatic tumors compared to primary BC tumors. However, the involvement of miR-623 in MMP1 upregulation in breast cancer brain metastatic cells (BCBMC) remains unexplored. Here, we investigated the role of miR-623 in MMP1 regulation and its impact on the extravasation of TNBC cells through the BE in vitro.

Materials and methods

A loss-and-gain of function method was employed to address the effect of miR-623 modulation on MMP1 expression. MMP1 regulation by miR-623 was investigated by real-time PCR, western blot, luciferase and transwell migration assays using an in vitro human BE model.

Results

Our results confirmed that brain metastatic TNBC cells express lower levels of miR-623 compared with cells having low propensity to spread toward the brain. miR-623 binds to the 3'-untranslated region of MMP1 transcript and downregulates its expression. Restoring miR-623 expression significantly decreased MMP1 expression, preserved the endothelial barrier integrity, and attenuated transmigration of BCBMC through the BE.

Conclusion

Our study elucidates, for the first time, the crucial role of miR-623 as MMP1 direct regulator in BCBMC and sheds light on miR-623 as a novel therapeutic target that can be exploited to predict and prevent brain metastasis in TNBC. Importantly, the presents study helps in unraveling a brain metastasis-specific microRNA signature in TNBC that can be used as a guide to personalized metastasis prediction and preventive approach with better therapeutic outcome.

SUBMITTER: Hammash D

PROVIDER: S-EPMC9354772 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Publications

miR-623 Targets Metalloproteinase-1 and Attenuates Extravasation of Brain Metastatic Triple-Negative Breast Cancer Cells.

Hammash Dua D Mahfood Mona M Khoder Ghalia G Ahmed Munazza M Tlili Abdelaziz A Hamoudi Rifat R Harati Rania R

Breast cancer (Dove Medical Press) 20220801

<h4>Background</h4>Most breast cancer-related deaths result from metastasis. Understanding the molecular basis of metastasis is needed for the development of effective targeted and preventive strategies. Matrix metalloproteinase-1 (MMP1) plays an important role in brain metastasis (BM) of triple-negative breast cancer (TNBC) by promoting extravasation of cancer cells across the brain endothelium (BE). MMP1 expression is controlled by endogenous microRNAs. Preliminary bioinformatics analysis has ...[more]

PMID: 35936987

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Project description:BackgroundThe triple-negative subtype of breast cancer is particularly challenging to treat due to its aggressiveness with a high risk of brain metastasis, and the lack of effective targeted therapies. Tubulin beta 2B class IIb (TUBB2B), a β-tubulin isoform regulating axon guidance during embryonic development, was found to be overexpressed in various types of cancers including triple-negative breast cancer (TNBC). However, its functional roles in breast cancer or metastasis remain unclear.MethodsTo identify TUBB2B as a novel molecular target in TNBC, we performed bioinformatics analysis to assess the association of TUBB2B expression and survival of patients. RNAscope in situ hybridization was used to examine TUBB2B expression in clinical breast tumor samples. The effect of TUBB2B knockdown on TNBC growth and brain metastasis colonization was evaluated by in vitro and in vivo assays. Mass spectrometry (MS) and biochemical experiments were performed to explore the underlying mechanisms. Preclinical efficacy of targeting TUBB2B was determined in xenograft studies using the siRNA-gold nanoparticle (siRNA-AuNP) approach.ResultsTUBB2B, but not other β-tubulin isoforms, is frequently overexpressed in TNBC primary tumors as well as brain metastases. We also find that upregulation of TUBB2B is associated with poor prognosis in breast cancer patients. Silencing TUBB2B induces tumor cell death and inhibits the outgrowth of brain metastasis. Mechanistically, we identify eukaryotic translation elongation factor 1 alpha 1 (eEF1A1) as a novel interacting partner of TUBB2B, revealing a previously unexplored role of TUBB2B in translational regulation. In line with its neural-related functions, TUBB2B overexpression in TNBC cells activates astrocytes, which in turn upregulate TUBB2B in tumor cells. These findings suggest a feed-forward interaction between TUBB2B in TNBC cells and astrocytes that promotes brain metastatic colonization. Furthermore, we demonstrate the potent inhibition of TNBC xenograft growth as well as brain metastatic colonization using TUBB2B siRNA-AuNP treatment, indicating potential clinical applications of targeting TUBB2B for TNBC.ConclusionsTUBB2B is a novel TNBC gene that plays a key role in promoting tumor cell survival and brain metastatic colonization, and can be targeted by siRNA-AuNPs as a treatment strategy.