Abstract:
Objective This study aims to investigate the effect of VAP33 on the proliferation, invasion, and metastasis of murine dendritic cell sarcoma.
Methods VAP33 cDNA was cloned, and gene recombinant technology was employed to construct a recombinant plasmid (pWPXL - VAP33) carrying the VAP33-GFP fusion gene. 293T cells were cotransfected with the recombinant plasmid and the helper plasmids PsPAX2 and MD2G using Lipofectamine 2000 to produce lentiviral particles. The recombinant lentiviruses were then used to infect DG6 cells with minimal endogenous VAP33 expression. Positive clones (DG6 - VAP33) were screened using fluorescence microscopy and Western blot analysis. The proliferation, invasion, metastasis, and cloning formation efficiency of DG6 - VAP33 cells were compared with those of DG6 through in vitro MTT, Transwell, and colony formation assays, respectively. Tumor models in KM mice were established to determine the effects of VAP33 on the behavior of malignant tumors in vivo. DG6 cells were used as the control in all experiments.
Results The recombinant plasmid expressing VAP33 - GFP fusion gene was successfully constructed with a titer of 6 × 107 IU/mL. After transfection, the VAP33 gene was highly expressed in the transfected DG6 cells. An in vitro assay showed that VAP33 overexpression decreased the proliferation of DG6 cells; the number of colonies formed by DG6 - VAP33 cells (52 ± 8 colonies / well) was lower than that in DG6 cells (36 ± 5 colonies / well; P < 0.05). The Transwell assay results showed that DG6-VAP33 had fewer membrane-penetrating cells than DG6 cells (36 ± 17 vs. 14 ± 11, P < 0.01), which indicated a decrease in invasiveness. When the DG6-VAP33 cells were subcutaneously transplanted into KM mice, the DG6-VAP33 cells exhibited a decreased proliferative ability. The tumorigenesis rate was 50 % (5 / 10), significantly lower than that of DG6 cells (100 %, 10 / 10; P < 0.05). Furthermore, the lung metastasis rate was 0 %, compared with 80 % for DG6.
Conclusion VAP33 overexpression decreased proliferation, tumorigenesis, invasion, and metastasis of murine dendritic cell sarcoma.