AIBP promotes cell proliferation and migration through the ERK1/2-MAPK signaling pathway in hepatocellular carcinoma

As a highly aggressive cancer, hepatocellular carcinoma (HCC) is often found at an advanced stage and has a poor prognosis. Therefore, in addition to the surgical treatment of HCC, the drug therapy for HCC is still under continuous exploration. The primary apolipoprotein of high-density lipoproteins (HDLs) is apolipoprotein A-I binding protein (AIBP), which has a significant impact on cholesterol metabolism, angiogenesis, and a wide range of inflammatory disorders, including cancer. The AIBP function in HCC is, however, yet unknown. This study aims to reveal the underlying mechanisms of AIBP influencing HCC proliferation and migration through mitogen-activated protein kinase (MAPK) pathways.

AIBP expression and its clinical prognostic association were investigated using The Cancer Genome Atlas (TCGA) data. The AIBP expression was studied in human HCC tissues using immunohistochemistry (IHC) and western blotting. Colony formation assays (CFAs) and cell counting kit-8 (CCK-8) were used to determine in vitro cell proliferation. Cell migration and invasion were evaluated using wound-healing and transwell assays. A xenograft tumor model was employed to investigate HCC cell proliferation in nude mice.

Tissues from HCC patients had much increased AIBP expression compared to nearby normal tissues. The prognosis for patients was bleak when AIBP expression was high. When AIBP was overexpressed in SMMC-7721 cells, the cells may become more proliferative, migrative, and invasive. In contrast, the HCC-LM3 cells' ability to proliferate, migrate, and invade was drastically decreased once AIBP was knocked down in vitro. Furthermore, in vivo research showed that AIBP overexpression may enhance cell proliferation in HCC. Finally, we discovered that AIBP could control the MAPK signaling pathway-involved genes expression, including P-MEK, MEK, c-Myc, P-ERK1/2, and ERK1/2, and that GDC-0994, a specific ERK1/2 inhibitor, could suppress the AIBP overexpression induced cell migration and proliferation abilities.

These findings demonstrated that the ERK/MAPK signaling pathway might be stimulated by AIBP in HCC tissues, leading to increased cell invasion, migration, and proliferation. It was hypothesized that AIBP might act as a useful prognostic and diagnostic marker for HCC.