The Influence Of Long Non-coding RNA Nene Z38 On Biological Characteristics Of Human Breast Cancer Cell BT549

It is a variety of mechanisms to regulate the structure and transcription of DNA, as well as the expression, conformation, and function of proteins by long noncoding RNA (lncRNA), and it has important impact in cellular, organizational, and individual levels. Through the previous research in our laboratory, we found a significant lncRNA gene named Z38. Researches have revealed that Z38 gene is highly expressed in breast cancer tissue, but displayed lower level of activity in para-tumor breast tissue.This paper takes Z38 gene as the research objects to probe the influence on biological characteristics of human breast cancer BT549 cells. The studies are mainly focused on cellular and animal levels. The following work is carried out.1. The lentiviral vector harboring RNAi sequence which targeted the Z38 gene was transfected into BT549 cells, and then screened by puromycin to acquire the stabled cell lines which Z38 gene was knockdown, and the fluorescent detection has been used to detect the infection. The expression level of Z38 gene was determined by RT-PCR. The results showed that the infection efficiency was almost 100%.2. The influences of cell viability and chemotherapy sensitivity from Z38 gene were determined by MTT assay. And the colony formation ability of cells was determined by cloning method. The OD(optical density) value was decreased markedly by MTT assay after interfering of the Z38 gene, namely a decrease in the cell viability. The data meant that the proliferation ability of the cells was weakened remarkably. The cell survival rate was decreased significantly when treated by adriamycin.3. The cell cycle distribution was analyzed before and after the interference of Z38 gene. The silencing of the Z38 gene could cause the cell cycle arrest clearly, thus achieved the goal in an inhibition of tumor growth.The block mainly occurred in the transition from S phase to G2 phase in interphase in cell division.4. The amount of CD44+/CD24-cells was compared between the transfected and the untransfected BT549 cells by the flow cytometry.The results revealed that the percentage of CD44+/CD24- cells with stem-cell-like properties declined significantly after the Z38 gene interference.5. The influence of differential expressions of Z38 in in vivo was tested by a xenograft model in nude mouse. The tumorigenesis abilities of BT549 cells were evaluated on the Z38 interference by measuring the tumor weight and volume.The results showed that inhibiting Z38 expression by gene silencing greatly suppressed breast cancer cell proliferation and tumorigenesis.The results of our experiment are concordant with our hypothesis, which support the same theory with the previous studies that Z38 may be a cancer-related gene.