Fayyad-Kazan Mohammad, ElDirani Rim, Ghassibe-Sabbagh Michella, Hamade Eva, Hadifeh Nader, El Majzoub Rania, Fayyad-Kazan Hussein, Badran Bassam
College of Arts and Sciences, Department of Natural and Applied Sciences, The American University of Iraq-Baghdad (AUIB), Baghdad, Iraq.
Laboratory of Cancer biology and Molecular Immunology, Faculty of Sciences-I, Lebanese University, Hadath-Beirut, Lebanon.
Nucleosides Nucleotides Nucleic Acids. 2025;44(4):302-317. doi: 10.1080/15257770.2024.2351134. Epub 2024 Jul 14.
Hypoxia, a critical feature during cancer development, leads to the stabilization and activation of the hypoxia-inducible factor 1-alpha (HIF-1α) to drive the expression of many target genes which in turn can promote many aspects of breast cancer biology, mainly metastasis and resistance to therapy. MicroRNAs are known to modulate the expression of many genes involved in breast cancer tumorigenesis. In this study, we examined the regulatory effect of miRNAs on HIF1α expression.
MCF-7 and MDA-MB-231 were cultivated under normoxia or hypoxia conditions. TaqMan-Low Density Array (TLDA) was used to characterize the miRNA signatures. Wild-Type (WT) or mutated fragments of HIF-1α 3'UTR containing the miR-138 potential target site were cloned downstream of the Renilla luciferase gene in the psiCHECK-1 plasmid. Luciferase assays were then carried out. A lentiviral vector containing copGFP as a reporter gene was prepared and transduced into MCF-7 and MDA-MB-231 cells to assess the effect of identified deregulated miRNAs on HIF-1α expression.
Under hypoxic conditions, MCF-7 cells showed deregulated expression for 12 miRNAs. In the case of MDA-MB-231 cells, 16 miRNAs were deregulated in response to hypoxia. Interestingly, miR-138 that was downregulated in both MCF-7 and MDA-MB-231 cells cultivated under hypoxic conditions appeared to have a binding site in 3'UTR of HIF-1α. Moreover, our results indicated that miR-138 could down regulate HIF-1α expression, upon binding directly to its 3'UTR.
Interestingly, our data highlights miR-138 as a potential therapeutic target to reduce HIF-1α expression and subsequently restrain breast cancer invasion and metastasis.
缺氧是癌症发展过程中的一个关键特征，它会导致缺氧诱导因子1α（HIF-1α）的稳定和激活，从而驱动许多靶基因的表达，进而促进乳腺癌生物学的多个方面，主要是转移和对治疗的抗性。已知微小RNA（miRNA）可调节许多参与乳腺癌肿瘤发生的基因的表达。在本研究中，我们检测了miRNA对HIF1α表达的调节作用。
MCF-7和MDA-MB-231细胞在常氧或缺氧条件下培养。使用TaqMan低密度阵列（TLDA）来表征miRNA特征。将含有miR-138潜在靶位点的HIF-1α 3'非翻译区（UTR）的野生型（WT）或突变片段克隆到psiCHECK-1质粒中海肾荧光素酶基因的下游。然后进行荧光素酶测定。制备了一个含有copGFP作为报告基因的慢病毒载体，并将其转导到MCF-7和MDA-MB-231细胞中，以评估已鉴定的失调miRNA对HIF-1α表达的影响。
在缺氧条件下，MCF-7细胞中有12种miRNA的表达失调。在MDA-MB-231细胞中，有16种miRNA因缺氧而表达失调。有趣的是，在缺氧条件下培养的MCF-7和MDA-MB-231细胞中均下调的miR-138似乎在HIF-1α的3'UTR中有一个结合位点。此外，我们的结果表明，miR-138在直接与其3'UTR结合后可下调HIF-1α的表达。
有趣的是，我们的数据突出了miR-138作为一个潜在的治疗靶点，可降低HIF-1α的表达，进而抑制乳腺癌的侵袭和转移。
