Breast cancer (BC) is malignant cancer that threatens the health of millions of females worldwide. Long non-coding RNA (lncRNA) small nucleolar RNA host gene 12 (SNHG12) has been identified as an oncogene in multiple cancers. However, the regulatory role of SNHG12 in BC cell progression is still obscured. The levels of SNHG12, miR-15a-5p, and Sal-like 4 (SALL4) in BC tumor tissues and cells were measured by qRT-PCR. Cell viability, apoptosis, migration, and invasion were examined by CCK8, flow cytometry, and transwell assay, respectively. The interaction between miR-15a-5p and SNHG12 or SALL4 was evaluated by dual-luciferase reporter assay. Protein expression of SALL4 was analyzed by western blot. Xenograft mice were established by subcutaneously injecting BC cells stably transfected with sh-SNHG12 and sh-NC. SNHG12 and SALL4 expressions were upregulated whereas miR-15a-5p was downregulated in BC tumors compared with normal tissues. Besides, miR-15a-5p was correlated with SNHG12 and SALL4 inversely as calculated by Pearson's correlation coefficient. More importantly, SNHG12 knockdown attenuated BC tumor growth in vitro and in vivo. Subsequently, dual-luciferase reporter assay confirmed the interaction between miR-15a-5p and SNHG12 or SALL4. The rescue experiments revealed that miR-15a-5p inhibitor restored SNHG12 silencing induced inhibition on BC cell proliferation, migration, invasion, and promotion of apoptosis. Additionally, SNHG12 was found to accelerate BC cell progression by absorbing miR-15a-5p to enhance SALL4 expression. SNHG12 promotes cell proliferation, migration, and invasion but suppresses apoptosis in BC by upregulating SALL4 expression via sponging miR-15a-5p, representing potential targets for the development of novel diagnosis and treatment methods.

ABSTRACT. Previous study has indicated that exposure to anesthesia in early development leads to neuro-apoptosis and is followed by longterm cognitive dysfunction. Given that larger numbers of pregnant women currently receive anesthesia during the first trimester, we wanted to mimic this process in vitro using mouse embryonic stem cells (mESCs) and to explore how different anesthetics affect the self-renewal of mESCs. In the present study, mESCs were exposed to dexmedetomidine, fentanyl, or remifentanil at clinical concentrations for 48 h. The mESCs were then analyzed for cell proliferation and apoptosis. Furthermore, we used flow cytometry to analyze the cell cycle and quantitative real-time polymerase chain reaction to detect the gene expression during the cell cycle as well as the relevant stemness markers. We found that prolonged anesthesia with dexmedetomidine or fentanyl significantly inhibited mESC proliferation, with fewer cell numbers as well as decreased expression of cyclin B and cyclin E mRNA compared to that in the control group; meanwhile, p21 and RB2 gene expression was increased. Additionally, increases or decreases in the proportion of cells in the G1 and S phases, respectively, were observed in the dexmedetomidine-and fentanyl-treated groups. These anesthetics also repressed the gene expression of mESC stemness makers such as Oct4 and Sox2. However, remifentanil seemed to have no significant influence on the self-renewal of mESCs. These results demonstrated that prolonged anesthesia with dexmedetomidine or fentanyl, but not remifentanil, inhibited mESC proliferation by blocking the G1 to S transition, and repressed the maintenance of mESC stemness.