OBJECTIVETo observe the effect of Feiyanning Granule (FYN) on tumor growth and cell cycle distribution in mice with Lewis lung cancer, as well as its influence on G1/S cell cycle checkpoint dominating signaling RB-E2F1 bio-axis.

METHODSModeled C57BL/6 mice were randomly divided into 6 groups: the model group (A), the DDP treated group (B) peritoneally injected with cisplatin 0.1 mg on d1, d3 and d5 after modeling, and the 4 FYN treated groups (C-F), administered via gastrogavage with FYN Decoction, and FYN Granule in small-, median- and high- dose respectively for 14 days. The tumour inhibiting rate, tumour weight, and body weight of mice were observed after treatment; cell cycle distribution was detected by flow cytometry (FCM), RB-E2F1mRNA expressions in tumour tissue were analyzed by RT-PCR, and their protein expressions by Western blot.

RESULTSTumour weight in the 5 treated groups was lower than that in the model group (P < 0.05, P < 0.01). Body weight in group E was significantly higher than that in group A and B (P < 0.05, P < 0.01). FCM analysis showed the proportion of G0/G1 phase was higher in group E than in group A, B and C (P < 0.01), and cancer cell proliferation index (PI) in group E was lower than in group B (P < 0.05, P < 0.01). RT-PCR showed mRNA level of E2F1 was lower, but that of RB was significantly higher in group E than those in group A, B and C respectively (P < 0.01). Westem blot analysis showed the protein expression of E2F1 was lower in group E and B than that in group A (P < 0.05), while the protein expression of Rb in group E was higher than that in group A, B and C (P < 0.05).

CONCLUSIONThe effect of FYN in inhibiting Lewis lung cancer growth was related to its intervention on cancer cell cycle distribution which blocks most tumor cells in G0/G1 phase. Moreover, FYN can reduce MDM2 expression, enhance P53 expression to influence cell cycle G1/S checkpoint dominating signaling, so as to achieve the effect of antagonizing lung cancer cell proliferation.