OBJECTIVETo explore the mechanism of polypeptide extract from scorpion venom (PESV) on promoting anti-tumor effects of cyclophosphamide (CTX).

METHODSThe Lewis lung tumor model was established by subcutaneously implanting Lewis lung cells into C57BL/6 mice. The tumor-bearing mice were randomly divided into 4 groups, i. e., the model group, the cyclophosphamide (CTX) group, the polypeptide extract from scorpion venom (PESV) group, and the combination group (CTX + PESV), 10 mice in each group. The tumor growth curve was recorded. Changes of vascular endothelial growth factor-A (VEGF-A) and transforming growth factor-beta1 (TGF-beta1) expressions in the tumor microenvironment were detected using reverse transcription PCR and immunohistochemical assay. Changes of dendritic cells (DCs) phenotype CD80 and CD86 expressions in the tumor tissue were detected using immunofluorescence chemical assay.

RESULTSAfter 21 successive days of treatment, the growth of Lewis lung cancer transplantation tumor in the combination group was obviously inhibited (P<0.05). Compared with the model group,the expressions of CD80 and CD86 in the PESV group was somewhat enhanced, while those in the CTX group was somewhat lowered. Compared with the CTX group, the fluorescent signal strength and expressions in the combination group somewhat increased. Compared with the model group, the expressions of TGF-beta1 and VEGF-A mRNA decreased in the PESV group and the CTX group (both P<0.05). Compared with the PESV group and the CTX group, the expressions of TGF-beta1 and VEGF-A in the combination group both decreased (both P<0.05).

CONCLUSIONPESV could inhibit the expressions of VEGF and TGF-beta1, promote the maturation of DCs, recover its antigen uptake presentation function, and reverse the immune injury to the body by CTX, thus playing a role in inducing the tumor cell apoptosis.