Background: This study aimed to determine the effect and mechanism of Xiaoaiping (XAP) injection
combined with S-1 in inhibiting the invasion and metastasis of human GC cells.
Methods: BGC-823 and MGC-803 cells were incubated in vitro, and the effects of treatment on the cytotoxicity
and proliferation of BGC-823 and MGC-803 cells were evaluated by MTT assay. Cell adhesion tests and Transwell
assays were used to detect the effects of Xiaoaiping injection combined with S-1 on the metastatic ability
of BGC-823 and MGC-803 cells. The expression of VEGF, Metalloproteinases (MMPs) and proteins related to
the Epithelial-Mesenchymal Transition (EMT) were detected by Western blotting. Meanwhile, a tumour model
was established in nude mice, and the effect of XAP combined with S-1 on BGC-823 cells in vivo was studied.
Results: Compared with the single drug group, the combination of XAP with S-1 increased the inhibition rate
(P<0.05). The adhesion test showed that the combination group significantly inhibited the adhesion of BGC-823
and MGC-803 cells (P<0.05). The combination of XAP with S-1 reduced the migration and invasion potential
of human GC BGC-823 and MGC-803 cells. Western blotting showed that the expression of VEGF, MMP-9, Ncadherin
and vimentin was decreased and E-cadherin expression was increased in the combination group compared
with these expression values in either the XAP or S-1 alone group (P<0.05). In vivo, we found that XAP
combined with S-1 had a significant inhibitory effect on the growth of tumours compared with XAP or S-1
alone. Immunohistochemistry showed that XAP combined with S-1 was able to enhance the levels of E-cadherin
and downregulate N-cadherin and vimentin.
Conclusion: The combination of XAP with S-1 can enhance the inhibitory effect of a single drug on proliferation,
invasion and metastasis. The mechanism may be related to the decrease in the expression of VEGF and
MMP-9 proteins and the effect on EMT.