Regulatory Mechanisms and Functional Roles of Hypoxia-Induced Long Non-Coding RNA MTORT1 in Breast Cancer Cells

Long non-coding RNAs (lncRNAs) have been found to participate in multiple genetic pathways in cancer. Also, mitochondria-associated lncRNAs have been discovered to modulate mitochondrial function and metabolism. Previously, we identified oxygen-responsive lncRNAs in MCF-7 breast cancer cells under different oxygen concentrations. Among them, a novel mitochondria-encoded lncRNA, mitochondrial oxygen-responsive transcript 1 (MTORT1), was chosen for further investigation. Nuclear, cytoplasmic, and mitochondrial fractionation assays were performed to evaluate the endogenous expression levels of MTORT1 in breast cancer cells. In vitro proliferation and migration assays were conducted to investigate the functions of MTORT1 in breast cancer cells by knockdown of MTORT1. RNA immunoprecipitation and luciferase reporter assays were used to examine the physical binding between MTORT1 and microRNAs. Our results showed that MTORT1 had low endogenous expression levels in breast cancer cells and was mainly located in the mitochondria. Knockdown of MTORT1 enhanced cell proliferation and migration, implying a tumor suppressor role of this novel mitochondrial lncRNA. MTORT1 served as sponge of miR-26a-5p to up-regulate its target genes, CREB1 and STK4. Our findings shed some light on the characterization, function, and regulatory mechanism of the novel hypoxia-induced mitochondrial lncRNA MTORT1, which functions as a microRNA sponge and may inhibit breast cancer progression. These data suggest that MTORT1 may be a candidate for therapeutic targeting of breast cancer progression.

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Macrophage conditioned media promotes adipocyte cancer-association, which in turn stimulates breast cancer proliferation and migration

10.21203/rs.3.rs-253267/v1 ◽

2021 ◽

Author(s):

Dale B. Bosco ◽

Yi Ren ◽

Karin A. Vallega ◽

Qing-Xiang Amy Sang

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Cancer Progression ◽

Breast Cancer Cells ◽

Conditioned Media ◽

Expression Levels ◽

Cell Counts ◽

And Migration ◽

Promote Breast Cancer ◽

Proliferation And Migration

Abstract Background Breast cancer is the most common cancer in women and the leading cause of female cancer deaths worldwide. Obesity causes chronic inflammation and is a risk factor for post-menopausal breast cancer and poor prognosis. Obesity triggers increased infiltration of macrophages into adipose tissue, yet little research has focused on the effects of macrophages in early stages of breast tumor development in obese patients. In this study, the effects of pro-inflammatory macrophages on breast cancer-adipocyte crosstalk were investigated.Methods An innovative human cell co-culture system was used to model the paracrine interactions among adipocytes, macrophages, and breast cancer cells, and how they facilitate tumor progression. The effects on cancer cells were examined using cell counts and migration assays. Quantitative reverse-transcription polymerase chain reaction was used to measure the expression levels of several cytokines and proteases to analyze adipocyte cancer-association.Results Macrophage conditioned media intensified the effects of breast cancer-adipocyte crosstalk. Adipocytes became delipidated and increased production of pro-inflammatory cytokines, even in the absence of cancer cells, although the expression levels were highest with all three cell components. As a result, co-cultured breast cancer cells became more aggressive, with increased proliferation and migration compared to adipocyte-breast cancer co-cultures treated with unconditioned media.Conclusions Macrophage conditioned media promotes adipocyte cancer-association. These macrophage-adipocyte paracrine interactions promote breast cancer cell proliferation and migration. Thus, macrophages may contribute to adipocyte inflammation and cancer-association and promote breast cancer progression.

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LncRNA NEAT1 accelerates breast cancer progression through regulating miR-410-3p/ CCND1 axis

Cancer Biomarkers ◽

10.3233/cbm-190721 ◽

2020 ◽

Vol 29 (2) ◽

pp. 277-290

Author(s):

Xuan Liu ◽

Weirong Yao ◽

Haiwei Xiong ◽

Qiang Li ◽

Yingliang Li

Keyword(s):

Breast Cancer ◽

Tumor Growth ◽

Cancer Cells ◽

Cancer Progression ◽

Breast Cancer Cells ◽

Breast Cancer Progression ◽

Cell Counting ◽

Luciferase Reporter ◽

Cancer Tissues

BACKGROUND: Breast cancer is the most common malignant tumor and usually occurs in women. Studies have shown that lncRNA nuclear enriched abundant transcript 1 (NEAT1) contributes to breast cancer progression. This study intends to further investigate the molecular mechanism of NEAT1 in breast cancer. METHODS: The expression levels of NEAT1, miR-410-3p and Cyclin D1 (CCND1) were detected by quantitative real-time PCR (qRT-PCR) in breast cancer tissues and cells. Kaplan-Meier analysis and the log-rank test were performed to determine the relationship between NEAT1 and overall survival. Cell Counting Kit-8 (CCK-8) assay analyzed cell proliferation. Transwell assay was performed to examine cell migration and invasion. The protein levels of CCND1 and epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, N-cadherin and Vimentin) were measured by western blot. The target relationship was predicted by bioinformatics analysis, and confirmed by luciferase reporter assay and RNA Immunoprecipitation (RIP) assay. Xenograft analysis was used to evaluate the tumor growth in vivo. RESULTS: NEAT1 and CCND1 were upregulated, while miR-410-3p was down-regulated in breast cancer tissues and cells. Higher NEAT1 expression level was associated with lower survival rate of breast cancer patients. Knockdown of miR-410-3p restored silenced NEAT1-mediated the inhibition of on proliferation, migration, invasion and EMT of breast cancer cells. In addition, NEAT1 regulated CCND1 expression by sponging miR-410-3p in breast cancer cells. NEAT1 knockdown blocked the tumor growth in vivo. CONCLUSION: NEAT1 induced breast cancer progression by regulating the miR-410-3p/CCND1 axis, indicating that NEAT1 may be a potential therapeutic target in breast cancer.

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Hypoxia-Induced MALAT1 Promotes the Proliferation and Migration of Breast Cancer Cells by Sponging MiR-3064-5p

Frontiers in Oncology ◽

10.3389/fonc.2021.658151 ◽

2021 ◽

Vol 11 ◽

Author(s):

Chung-Hsien Shih ◽

Li-Ling Chuang ◽

Mong-Hsun Tsai ◽

Li-Han Chen ◽

Eric Y. Chuang ◽

...

Keyword(s):

Breast Cancer ◽

Tumor Growth ◽

Cancer Cells ◽

Cancer Progression ◽

Breast Cancer Cells ◽

Cellular Migration ◽

Expression Levels ◽

Promote Tumor Growth ◽

Rna Immunoprecipitation ◽

And Migration

Hypoxia, a common process during tumor growth, can lead to tumor aggressiveness and is tightly associated with poor prognosis. Long noncoding RNAs (lncRNAs) are long ribonucleotides (>200 bases) with limited ability to translate proteins, and are known to affect many aspects of cellular function. One of their regulatory mechanisms is to function as a sponge for microRNA (miRNA) to modulate its biological functions. Previously, MALAT1 was identified as a hypoxia-induced lncRNA. However, the regulatory mechanism and functions of MALAT1 in breast cancer are still unclear. Therefore, we explored whether MALAT1 can regulate the functions of breast cancer cells through miRNAs. Our results showed the expression levels of MALAT1 were significantly up-regulated under hypoxia and regulated by HIF-1α and HIF-2α. Next, in contrast to previous reports, nuclear and cytoplasmic fractionation assays and fluorescence in situ hybridization indicated that MALAT1 was mainly located in the cytoplasm. Therefore, the labeling of MALAT1 as a nuclear marker should be done with the caveat. Furthermore, expression levels of miRNAs and RNA immunoprecipitation using antibody against AGO2 showed that MALAT1 functioned as a sponge of miRNA miR-3064-5p. Lastly, functional assays revealed that MALAT1 could promote cellular migration and proliferation of breast cancer cells. Our findings provide evidence that hypoxia-responsive long non-coding MALAT1 could be transcriptionally activated by HIF-1α and HIF-2α, act as a miRNA sponge of miR-3064-5p, and promote tumor growth and migration in breast cancer cells. These data suggest that MALAT1 may be a candidate for therapeutic targeting of breast cancer progression.

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M2 macrophages contribute to cell proliferation and migration of breast cancer

10.21203/rs.3.rs-39373/v1 ◽

2020 ◽

Author(s):

Daoyuan Tu ◽

Jin Dou ◽

Mingkao Wang ◽

Haiwen Zhuang ◽

Xiaoyu Xiaoyu

Keyword(s):

Breast Cancer ◽

Cell Proliferation ◽

Cancer Cells ◽

Cancer Progression ◽

Breast Cancer Cells ◽

M2 Macrophage ◽

M2 Macrophages ◽

Cell Proliferation And Migration ◽

And Migration ◽

Proliferation And Migration

Abstract Background: Breast cancer is a kind of malignant tumor that severely threatens women’s health and life worldwide. Macrophages have been reported to mediate tumor progression, while the potential mechanism still needs further identification.Methods: Human monocytic cell line THP-1 was used to induce M2-macrophage. Real-time PCR and western blot were performed to determine gene expression in mRNA and protein level, respectively. Cell proliferation was determined using MTT assays, while cell migration was detected based on the scratch wound healing assays.Results: The supernatant medium of M2-macrophages incubated breast cancer cells showed increased cell proliferation and reduced expression of IRF-7. Overexpression of IRF-7 reversed the increased level of M2-macrophage induced cell proliferation and migration. The supernatant medium of M2-macrophages incubation promoted miR-1587 expression in breast cancer cells. miR-1587 overexpression promoted cell proliferation and migration of breast cancer. In addition, miR-1587 knockdown suppressed cell proliferation and migration that induced by M2-macrophages. miR-1587 targets IRF-7 to regulate its expression. Knockdown of IRF-7 reversed the effects of miR-1587 knockdown on cell proliferation and migration.Conclusion: Collectively, this study revealed that miR-1587/IRF-7 mediated the mechanism of M2-macrophages-induced breast cancer progression, and this would shed light on the further clinical therapy of breast cancer.

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Circular RNA circCCDC85A inhibits breast cancer progression via acting as a miR-550a-5p sponge to enhance MOB1A expression

Breast Cancer Research ◽

10.1186/s13058-021-01497-6 ◽

2022 ◽

Vol 24 (1) ◽

Author(s):

Lingjiao Meng ◽

Sheng Chang ◽

Yang Sang ◽

Pingan Ding ◽

Liuxin Wang ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Cancer Progression ◽

Breast Cancer Cells ◽

Breast Cancer Progression ◽

Luciferase Reporter Assay ◽

Luciferase Reporter ◽

Reporter Assay ◽

Qrt Pcr ◽

Cancer Tissues

Abstract Background A growing body of evidence indicates that abnormal expression of circular RNAs (circRNAs) plays a crucial role by acting as molecular sponges of microRNAs (miRNAs) in various diseases, including cancer. In this study, we explored whether circCCDC85A could function as a miR-550a-5p sponge and influence breast cancer progression. Methods We detected the expression of circCCDC85A in breast cancer tissues and cells using fluorescence in situ hybridization (FISH) and quantitative reverse transcription polymerase chain reaction (qRT-PCR). CCK-8 and colony formation assay were used to detect the proliferative ability of breast cancer cells. Wound healing assay and transwell migration and invasion assays were used to detect the migrative and invasive abilities of breast cancer cells. We also examined the interactions between circCCDC85A and miR-550a-5p using FISH, RNA-binding protein immunoprecipitation (RIP), and luciferase reporter assay. Moreover, we performed luciferase reporter assay, qRT-PCR, and Western blot to confirm the direct targeting of miR-550a-5p to MOB1A. Results The expression of circCCDC85A in breast cancer tissues was obviously lower than that in normal breast tissues. Over-expression of circCCDC85A substantially inhibited the proliferative, migrative, and invasive ability of breast cancer cells, while knocking down of circCCDC85A enhanced the aforementioned properties of breast cancer cells. Moreover, enforced expression of circCCDC85A inhibits the oncogenic activity of miR-550a-5p and increases the expression of MOB1A targeted by miR-550a-5p. Further molecular mechanism research showed that circCCDC85A may act as a molecular sponge for miR-550a-5p, thus restoring miR-550a-5p-mediated targeting repression of tumor suppressor MOB1A in breast cancer cells. Conclusion Our findings provide novel evidence that circCCDC85A inhibits the progression of breast cancer by functioning as a molecular sponge of miR-550a-5p to enhance MOB1A expression.

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Sympathetic activity in breast cancer and metastasis: partners in crime

Bone Research ◽

10.1038/s41413-021-00137-1 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Francisco Conceição ◽

Daniela M. Sousa ◽

Joana Paredes ◽

Meriem Lamghari

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Bone Remodeling ◽

Cancer Progression ◽

Breast Cancer Cells ◽

Sympathetic Innervation ◽

Breast Cancer Progression ◽

Vicious Cycle ◽

Native Bone ◽

Cancer Management

AbstractThe vast majority of patients with advanced breast cancer present skeletal complications that severely compromise their quality of life. Breast cancer cells are characterized by a strong tropism to the bone niche. After engraftment and colonization of bone, breast cancer cells interact with native bone cells to hinder the normal bone remodeling process and establish an osteolytic “metastatic vicious cycle”. The sympathetic nervous system has emerged in recent years as an important modulator of breast cancer progression and metastasis, potentiating and accelerating the onset of the vicious cycle and leading to extensive bone degradation. Furthermore, sympathetic neurotransmitters and their cognate receptors have been shown to promote several hallmarks of breast cancer, such as proliferation, angiogenesis, immune escape, and invasion of the extracellular matrix. In this review, we assembled the current knowledge concerning the complex interactions that take place in the tumor microenvironment, with a special emphasis on sympathetic modulation of breast cancer cells and stromal cells. Notably, the differential action of epinephrine and norepinephrine, through either α- or β-adrenergic receptors, on breast cancer progression prompts careful consideration when designing new therapeutic options. In addition, the contribution of sympathetic innervation to the formation of bone metastatic foci is highlighted. In particular, we address the remarkable ability of adrenergic signaling to condition the native bone remodeling process and modulate the bone vasculature, driving breast cancer cell engraftment in the bone niche. Finally, clinical perspectives and developments on the use of β-adrenergic receptor inhibitors for breast cancer management and treatment are discussed.

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