School of Medicine and Health Sciences Poster Presentations

Title

miR-141 Regulates CDC25a in Breast Cancer

Poster Number

3

Document Type

Poster

Publication Date

3-2016

Abstract

Background: The most aggressive strains of breast cancer cells are found to be ER-/PR-/HER2-. miR-141, a member of the miR-200 family of miRNAs, has been identified for its role in breast cancer progression and has demonstrated differential expression in breast cancer cell lines. Moreover, our bioinformatics analysis suggests that miR-141 targets CDC25A, a known protein phosphotase that regulates the transition of cells from G1 to S phase. We therefore hypothesize that miR-141 binds to and regulates CDC25A gene, acting as a tumor suppressor miRNA.

Methods: qRT-PCR analysis was used to determine the expression of miR-141 in five breast cell lines, including MCF-7, T47D, MCF-10A, MDA-MB-231 and HS578T. After microdissection from breast cancer FFPE samples, we analyzed the expression of miR-141 during the progression of breast cancer, from normal, ADH, DCIS to IDC. Based on our target scan analysis, we selected ten probable targets for miR-141, including CDC25A. CDC25A expression was analyzed in two representative cell lines by qRT-PCR and Western blot, MCF-7 and MDA-MB-231 when transfected with control miR, miR-141 mimic, miR-141 inhibitor and inhibitor-mock. MTT assays were also used to explore cell viability following transfection of control miR and mimic in these same cell lines. A luciferase assay is underway to determine the binding specificity of miR-141 to CDC25A.

Results: Expression of miR-141 was found to be hardly detectable in MDA-MB-231 and HS578T relative to the other three cell lines. In patient samples, miR-141 expression was downregulated in IDC compared to early stage in 40% of the cases, and upregulated in 47%, with no clear change observed in 13% (n = 15). qRT-PCR detection for CDC25A expression was decreased in MCF-7 and MDA-MB-231 cells when miR-141 was overexpressed. Western Blot analysis exhibited lower expression of CDC25A in MDA-MB-231 cells transfected with miR-141 mimic compared to those transfected with mock or inhibitor. The MTT assay revealed decreased cell proliferation in both MCF-7 and MDA-MB-231 when transfected by miR-141 mimic.

Conclusions: Overall, these data suggest that miR-141 targets CDC25A, regulating its expression. Therefore, miR-141 may provide a novel approach for decreasing cell proliferation and halting tumor growth in breast cancer.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Open Access

1

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Presented at: GW Research Days 2016

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miR-141 Regulates CDC25a in Breast Cancer

Background: The most aggressive strains of breast cancer cells are found to be ER-/PR-/HER2-. miR-141, a member of the miR-200 family of miRNAs, has been identified for its role in breast cancer progression and has demonstrated differential expression in breast cancer cell lines. Moreover, our bioinformatics analysis suggests that miR-141 targets CDC25A, a known protein phosphotase that regulates the transition of cells from G1 to S phase. We therefore hypothesize that miR-141 binds to and regulates CDC25A gene, acting as a tumor suppressor miRNA.

Methods: qRT-PCR analysis was used to determine the expression of miR-141 in five breast cell lines, including MCF-7, T47D, MCF-10A, MDA-MB-231 and HS578T. After microdissection from breast cancer FFPE samples, we analyzed the expression of miR-141 during the progression of breast cancer, from normal, ADH, DCIS to IDC. Based on our target scan analysis, we selected ten probable targets for miR-141, including CDC25A. CDC25A expression was analyzed in two representative cell lines by qRT-PCR and Western blot, MCF-7 and MDA-MB-231 when transfected with control miR, miR-141 mimic, miR-141 inhibitor and inhibitor-mock. MTT assays were also used to explore cell viability following transfection of control miR and mimic in these same cell lines. A luciferase assay is underway to determine the binding specificity of miR-141 to CDC25A.

Results: Expression of miR-141 was found to be hardly detectable in MDA-MB-231 and HS578T relative to the other three cell lines. In patient samples, miR-141 expression was downregulated in IDC compared to early stage in 40% of the cases, and upregulated in 47%, with no clear change observed in 13% (n = 15). qRT-PCR detection for CDC25A expression was decreased in MCF-7 and MDA-MB-231 cells when miR-141 was overexpressed. Western Blot analysis exhibited lower expression of CDC25A in MDA-MB-231 cells transfected with miR-141 mimic compared to those transfected with mock or inhibitor. The MTT assay revealed decreased cell proliferation in both MCF-7 and MDA-MB-231 when transfected by miR-141 mimic.

Conclusions: Overall, these data suggest that miR-141 targets CDC25A, regulating its expression. Therefore, miR-141 may provide a novel approach for decreasing cell proliferation and halting tumor growth in breast cancer.