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MiR-221 promotes stemness of breast cancer cells by targeting DNMT3b.

ABSTRACT: Cancer stem cells (CSCs) are a small part of the heterogeneous tumor cell population possessing self-renewal and multilineage differentiation potential as well as a great ability to sustain tumorigenesis. The molecular pathways underlying CSC phenotype are not yet well characterized. MicroRNAs (miRs) are small noncoding RNAs that play a powerful role in biological processes. Early studies have linked miRs to the control of self-renewal and differentiation in normal and cancer stem cells. We aimed to study the functional role of miRs in human breast cancer stem cells (BCSCs), also named mammospheres. We found that miR-221 was upregulated in BCSCs compared to their differentiated counterpart. Similarly, mammospheres from T47D cells had an increased level of miR-221 compared to differentiated cells. Transfection of miR-221 in T47D cells increased the number of mammospheres and the expression of stem cell markers. Among miR-221's targets, we identified DNMT3b. Furthermore, in BCSCs we found that DNMT3b repressed the expression of various stemness genes, such as Nanog and Oct 3/4, acting on the methylation of their promoters, partially reverting the effect of miR-221 on stemness. We hypothesize that miR-221 contributes to breast cancer tumorigenicity by regulating stemness, at least in part through the control of DNMT3b expression.

SUBMITTER: Roscigno G

PROVIDER: S-EPMC4808019 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature

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MiR-221 promotes stemness of breast cancer cells by targeting DNMT3b.

Roscigno Giuseppina G Quintavalle Cristina C Donnarumma Elvira E Puoti Ilaria I Diaz-Lagares Angel A Iaboni Margherita M Fiore Danilo D Russo Valentina V Todaro Matilde M Romano Giulia G Thomas Renato R Cortino Giuseppina G Gaggianesi Miriam M Esteller Manel M Croce Carlo M CM Condorelli Gerolama G

Oncotarget 20160101 1

Cancer stem cells (CSCs) are a small part of the heterogeneous tumor cell population possessing self-renewal and multilineage differentiation potential as well as a great ability to sustain tumorigenesis. The molecular pathways underlying CSC phenotype are not yet well characterized. MicroRNAs (miRs) are small noncoding RNAs that play a powerful role in biological processes. Early studies have linked miRs to the control of self-renewal and differentiation in normal and cancer stem cells. We aime ...[more]

PMID: 26556862

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Project description:Breast malignancy remains one of the most common causes of cancer-associated mortalities among women. MicroRNA (miR)-221 and miR-222 are homologous miRs and have a substantial impact on cancer progression. In the present study, the regulatory mechanisms of miR-221/222 and its target annexin A3 (ANXA3) in breast cancer cells were investigated. Breast tissue samples were collected to evaluate the expression patterns of miR-221/222 levels in breast cancer cell lines and cancer tissues according to clinical characteristics. The levels of miR-221/222 were increased or decreased in cancer cell lines compared with normal breast cell lines according to cell line subtype. Subsequently, the changes in the progression and invasion of breast cancer cells were investigated using cell proliferation, invasion assay, gap closure and colony formation assays. Western blotting of cell cycle proteins and flow cytometry were performed to evaluate the possible pathway of miR-221/222 and ANXA3 axis. Chemosensitivity tests were performed to explore the suitability of the miR-221/222 and ANXA3 axis as a therapeutic target in breast cancer. The expression levels of miR-221/222 were associated with aggressive characteristics of breast cancer subtypes. Cell transfection assay demonstrated the regulation of breast cancer proliferation and invasiveness by miR-221/222. MiR-221/222 directly targeted the 3'-untranslated region of ANXA3 and suppressed the expression of ANXA3 at the mRNA and protein levels. In addition, miR-221/222 negatively regulated cell proliferation and the cell cycle pathway in breast cancer cells by targeting ANXA3. In combination with adriamycin, downregulation of ANXA3 may sensitize adriamycin-induced cell death to induction of persistent G2/M and G0/G1 arrest. Decreased expression of ANXA3 through increased expression of miR-221/222 reduced breast cancer progression and increased the effectiveness of the chemotherapy drug. The present results indicated the miR-221/222 and ANXA3 axis to be a possible novel therapeutic target for the treatment of breast cancer.

Project description:BackgroundColorectal cancer is one of the most common malignancy in the world. It has been reported that cancer stem cells (CSCs) serve as the primary drivers of tumorigenesis and tumor progression. There is an urgent need to explore novel molecules that regulate CSCs or their signatures. Increasing evidence has shown that miRNAs are involved in tumorigenesis and progression. Here, we aim to explore the regulatory effect and mechanism of miR-3065-3p on the stemness of colorectal cancer.MethodsThe expression of miR-3065-3p in colorectal cancer and the association of miR-3065-3p expression with prognosis of patients with colorectal cancer were analyzed using TCGA dataset or clinical cases. Gain or loss of function in different models, including colorectal cancer cell lines and orthotopic xenograft or liver metastatic mouse model, were used to investigate the effects of miR-3065-3p on colorectal cancer stemness and metastasis in vitro and in vivo. Cancer stemness was analyzed by detecting the ability of migration and invasion, NANOG, OCT4, and SOX2 expression, ALDH activity and sphere formation. In addition, the interaction of miR-3065-3p and cytokine receptor-like factor 1 (CRLF1) was analyzed theoretically and identified by the luciferase reporter assay. Moreover, the correlation between CRLF1 expression and miR-3065-3p was analyzed in colorectal cancer tissues. Finally, the effect of CRLF1 on the stemness and metastasis of colorectal cancer in vitro and in vivo was assessed.ResultsIn this report, we found that miR-3065-3p was overexpressed in colorectal cancer and that its high expression was associated with poor prognosis of patients with colorectal cancer. miR-3065-3p promotes the stemness and metastasis of colorectal cancer. Furthermore, CRLF1 was the downstream target of miR-3065-3p and inhibited the stemness of colorectal cancer. In addition, CRLF1 expression was negatively correlated with miR-3065-3p in colorectal cancer tissues. And, CRLF1 mediated the effects of miR-3065-3p on promoting stemness of colorectal cancer cells.ConclusionOur data suggest that miR-3065-3p promoted the stemness and metastasis of colorectal cancer by targeting CRLF1. miR-3065-3p might serve as a promising prognostic marker as well as a therapeutic target for colorectal cancer.

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MiR-221 promotes stemness of breast cancer cells by targeting DNMT3b.

Publications

MiR-221 promotes stemness of breast cancer cells by targeting DNMT3b.

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