[Circ-LAMP1 Promotes Malignant Progression of Acute Myeloid Leukemia Cells by Regulating the miR-194-5p/SALL4 Axis]

To investigate the effect of circular RNA LAMP1 (circ-LAMP1) on the malignant progression of acute myeloid leukemia (AML) cells by regulating the miR-194-5p/SALL4 axis.

Bone marrow fluid samples were collected from patients with AML and patients with megaloblastic anemia (MA). Human bone marrow stromal cells HS-5 and AML cells HL-60 were cultured in vitro. Quantitative real-time PCR (qRT-PCR) was used to detect the expression levels of circ-LAMP1, miR-194-5p, and SALL4 mRNA in bone marrow samples and cells. HL-60 cells were divided into the following groups: control, si-NC, si-LAMP1, si-LAMP1+anti-miR-NC, and si-LAMP1+anti-miR-194-5p. CCK-8 assay and colony formation assay were used to detect cell proliferation ability; Transwell assay was used to detect cell invasion ability; Flow cytometry was used to detect cell apoptosis; Western blot was utilized to measure the expression levels of SALL4 protein and apoptosis-related proteins (Bax and Bcl-2) in cells; Dual-luciferase assay was conducted to verify the targeting relationship between miR-194-5p and circ-LAMP1, as well as between miR-194-5p and SALL4.

In the bone marrow samples of AML patients and HL-60 cells, the expression levels of circ-LAMP1 and SALL4 mRNA were significantly upregulated ( P < 0.05), while the level of miR-194-5p was significantly downregulated ( P < 0.05). After silencing circ-LAMP1 (si-LAMP1 group), the cell viability, colony formation ability, number of invasive cells, as well as the expression levels of circ-LAMP1, SALL4 mRNA, SALL4 protein and Bcl-2 protein in HL-60 cells were significantly decreased ( P < 0.05); Meanwhile, the apoptosis rate, miR-194-5p expression level, and Bax protein expression level were significantly increased ( P < 0.05). Inhibition of miR-194-5p significantly reversed the aforementioned effects mediated by circ-LAMP1 silencing. Dual-luciferase assay confirmed that circ-LAMP1 can specifically bind to miR-194-5p, and miR-194-5p directly targets the 3'UTR of SALL4 .

Circ-LAMP1 may promote the proliferation and invasion of AML cells and inhibit cell apoptosis by regulating the miR-194-5p/SALL4 axis.