Is miR-144 an effective inhibitor of PTEN mRNA: a controversy in breast cancer Vahid Kia 1 & Maryam Sharif Beigli 2 & Vahedeh Hosseini 3,4 & Ameneh Koochaki 3 & Mahdi Paryan 5 & Samira Mohammadi-Yeganeh 3,4 Received: 10 February 2018 /Accepted: 23 July 2018 / Editor: Tetsuji Okamoto # The Society for In Vitro Biology 2018 Abstract Breast cancer is the first common cancer among women worldwide. One of the major signaling pathways playing a role in the onset and progression of this disease is PI3K/Akt/mTOR, which can be inhibited by PTEN. miRNAs are small non-coding molecules that regulate the expression of their targets by inhibition or suppression, and thus, their dysregulated expression results in the develop- ment of cancer. Using various software applications predicting miRNAs and evaluating GEO microarray data, miR-144 was selected as an inhibitor of PTEN. The expression of miR-144 and PTEN was evaluated in 18 triple negative breast cancer (TNBC) clinical samples and cell lines including 4T1, MDA-MB-231, MDA-MB-468, SK-BR-3, and MCF-7 in comparison with normal cells. PTEN and miR-144 expression analysis revealed their elevated expression in MCF-7 cells. MDA-MB-468, SK-BR-3, and MDA-MB-231 cells showed decreased levels of PTEN and increased levels of miR-144. In contrast, 4T1 cells had an increased expression of PTEN and decreased expression of miR-144. In clinical samples, miR-144 was up-regulated in 22% of the cases and PTEN was down-regulated in 78% of the cases. The results showed that the expression of PTEN and miR-144 was inversely correlated in metastatic breast cancer cell lines. However, in TNBC clinical samples, there was no correlation between the expres- sion of miR-144 and PTEN. Literature shows that there are other influencing factors affecting the expression of miRNAs. Therefore, care should be taken in interpreting the results of gene expression studies and its relation with cancer diagnosis/prognosis. Keywords Triple negative breast cancer . PTEN . miR-144 Introduction Breast cancer is the second most prevalent cancer among women after skin cancer (DeSantis et al. 2014). It is the cause of 33% of women’ s cancers and 19% of cancer-related deaths in women (Suva et al. 2011). It is one of the major concerns in various societies, and thanks to the improvements in screening and diagnostic methods, general knowledge about breast can- cer is more than other types of cancers (Smith et al. 2012). PTEN is located on 10q23 and has a product similar to phosphatase and tensin, hence its name. This chromosomal locus (PTEN/MMAC1/TEP1) encodes a tyrosine phosphatase that seems to have a tumor suppressor role, and inactivating mutations in the gene have been observed in a variety of cancers such as glioma (Rasheed et al. 1997), prostate (Cairns et al. 1997), and breast cancer (Tamura et al. 1999). Vahid Kia and Maryam Sharif Beigli contributed equally to this work. * Mahdi Paryan m_paryan@pasteur.ac.ir * Samira Mohammadi-Yeganeh s.mohammadiyeganeh@sbmu.ac.ir 1 Department of Medical Biotechnology and nanotechnology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran 2 Islamic Azad University, East Tehran branch Campus, Tehran, Iran 3 Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4 Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran 5 Department of Research and Development, Production and Research Complex, Pasteur Institute of Iran, P.O. Box: 3159915111, Tehran, Iran In Vitro Cellular & Developmental Biology - Animal https://doi.org/10.1007/s11626-018-0282-2