Screening Of MicroRNAs Involved In Breast Cancer Cell Proliferation And Apoptosis

Cancers are class of diseases that are difficult to cure. Along with the process of medicine science, some therapeutic methods such as exairesis, radiotherapy and chemotherapy were developed to treat cancer. But it is hard to eradicate cancer since their limitless replicative potential and resistance of cell death. Breast cancer is common in female patients, and the mobidity of breast cancer has ranked the first among the female cancer patients. The roles of oncogenes in tumorigenesis and development of breast cancer are revealed in the past decades, they could regulate the proliferation, migration and survival of cancer cells. MicroRNA is a kind of single strand small non-coding RNA, length of about22nucleotides, widely distributed in eukaryote, mainly through the fully or partially complementary combination with3" untranslation region of its target mRNA, lead to target mRNA degradation or translation suppression. Several studies demonstrated that miRNA plays critical roles in the tumorigenesis of breast cancer, thus an exciting idea is that inhibit oncogenes via miRNA pathway in breast cancer.We use the human breast cancer cell line MCF-7as model to elucidate miRNA roles in breast cancer cell growth. Four main parts of our work are:1. miRNA selection. We predicted miRNA targets by using4microRNA target gene prediction software include miRanda, miRDB, PicTar and TargetScan. Then we selected miRNAs (miR-124, miR-181a-1, miR-211, miR-302a, miR-302b, miR-302c and miR-367) which mainly target to cell growth associated genes.2. Lenti-vector construction. Based on the sequence of pre-miRNA from miRBase, we synthesis two complementary oligos. Then annealing two oliogs to form a double-stranded DNA, then ligated into pLVX-shRNA2lentivirus expression vector.3. Lentivirus infection. Packaging lentiviruses in293T cell line via calcium phosphate based transfection, collect virus and infect human breast cancer cell line MCF-7.4. Evaluation of cell growth. After infection, we measured cell growth rate via CCK8method. Combined with estimating of oncogene expression, we validated several tumor-inhibitive miRNAs.