[Abnormal expression of APRIL in colorectal cancer cells promotes tumor growth and metastasis].

OBJECTIVE

To investigate the effects of a proliferation-inducing ligand (APRlL) on colorectal cancer (CRC) cell growth and migration, and to observe the role of APRIL in CRC biological behavior.

METHODS

The siRNA plasmid vector targeting APRIL gene (APRIL-siRNA) was transfected into human colorectal cancer SW480 cells and recombinant human APRIL (rhAPRIL) was used to stimulate human colorectal cancer HCT-116 cells. Cell proliferation activity was analyzed using cell counting kit-8 (CCK-8), cell cycle was detected by flow cytometry, and the protein expression of cyclin D1, p21 and Bcl-2 was detected by Western blot analysis. Tumor cell migration and invasion were measured by Transwell chambers. RT-PCR was applied to examine the mRNA expression level of MMP-2 and MMP-9. APRIL-siRNA was used to transfect directly SW480 cells, which were injected subcutaneously into nude mice, then the tumor growth and metastasis were observed.

RESULTS

Cell proliferation ability of APRIL-siRNA-transfected SW480 cells was drastically repressed, and the percentage of G0/G1 phase cells was significantly increased (t = 4.12, P < 0.05), accompanied with depressed cyclin D1, Bcl-2 expression and elevated p21 expression. Cell proliferation ability of rhAPRIL-stimulated HCT-116 cells was promoted with a decreased G0/G1 phase ratio (t = 3.31, P < 0.05). cyclin D1 and Bcl-2 protein expression was up-regulated while p21 was down-regulated by rhAPRIL stimulation. Metastatic and invasive capacities of APRIL-siRNA-transfected SW480 cells were significantly inhibited compared with their respective controls (both P < 0.05), accompanied with the deregulated MMP-2 and MMP-9 mRNA expression. Metastatic and invasive capacities of rhAPRIL-stimulated HCT-116 cells were promoted with up-regulated MMP-2 and MMP-9 mRNA expression(both P < 0.05). Tumor growth in the group transfected with APRIL-siRNA appeared to be slower than that in the control groups and the expression of MMP-2, MMP-9 in tumor tissues was depressed in the APRIL-siRNA group.

CONCLUSIONS

APRIL facilitates tumor growth and metastasis, and is associated with carcinogenesis and prognosis. Our findings suggest that APRIL might be used as a novel target for the intervention and therapy of colorectal cancer.