OBJECTIVETo explore the effect of HMGB1 on the VEGF-C expression and proliferation of esophageal squamous cancer cells as well as its possible mechanism.

METHODSA cassette encoding siRNA targeting HMGB1 mediated by rAAV was constructed, the rAAV-siHMGB1-hrGFP, and a vector encoding siRNA mismatching HMGB1 was constructed, the rAAV-miHMGB1-hrGFP. This experiment in vitro included three groups, namely, the blank control group (group A) of KYSE150 cells transfected by rAAV-hrGFP, negative mismatch control group (group B) of KYSE150 cells transfected with rAAV-miHMGB1-hrGFP, and RNA interference group (group C) of KYSE150 cells transfected with rAAV-siHMGB1-hrGFP. We examined the expression of HMGB1 mRNA and protein in the three group cells by real-time PCR and Western blot after 24 h and 48 h, respectively. Then, VEGF-C expression and cell proliferation in the three group cells with or without sRAGE, as an inhibitor of RAGE signal pathway, were assayed by ELISA and MTT after 24 h.

RESULTSThe expression of HMGB1 mRNA and protein in KYSE150 cells in vitro in the group C transfected with rAAV-siHMGB1-hrGFP at the final concentration of 2×10(6) v.g/cell was significantly lower than that of the group A or B after 24 h and 48 h (P < 0.01). The VEGF-C expression of KYSE150 cells was (502.43 ± 13.10) pg/ml in the group C, significantly reduced in comparison with that of the group A (686.40 ± 10.94) pg/ml or group B (682.31 ± 9.61) pg/ml after 24 h (P < 0.05). At the same time, the proliferation of KYSE150 cells in the group C was significantly inhibited compared with that of groups A and B after 24 h (P < 0.01). Moreover, sRAGE at the final concentration of 0.2 µg/ml inhibited the VEGF-C expression and proliferation of KYSE150 cells compared with the corresponding group without sRAGE after 24 h (P < 0.01 or P < 0.05). However, there was no significant difference of the VEGF-C expression and proliferation of KYSE150 cells with sRAGE in the group C compared with that of cells with sRAGE of the group A or group B after 24 h (P > 0.05).

CONCLUSIONSIn esophageal squamous cell carcinoma, HMGB1 can promote the VEGF-C expression and proliferation of the cancer cells through RAGE signal pathway, and HMGB1-RAGE may become a potential target for cell proliferation and lymph node metastasis of this cancer.