OBJECTIVETo explore the effect of Lignum Sappan (LS) containing serum on the proliferation cycle arrest of human lung cancer cell line PG and its molecular mechanism.

METHODSThe lung cancer PG cells were divided into four groups, i.e., the blank control group, the LS group, the LS plus cisplatin group, and the cisplatin group. They were cultured by RPMI-1640 with 20% blank serum, RPMI-1640 with 20% LS containing serum, RPMI-1640 with 20% LS containing serum plus 1 microg/mL cisplatin, and RPMI-1640 with 20% blank serum plus 1 microg/mL cisplatin, respectively. The morphology of PG cells was observed using light microscope and laser scanning confocal microscope in each group. The cell cycle arrest was observed using flow cytometry. The expression of P16 and Rb1 mRNA was tested by PCR method.

RESULTSUnder the light microscope and laser scanning confocal microscope, the apoptosis degree of PG cells in the LS group was significant, but less than that of the LS plus cisplatin group as well as the cisplatin group. Compared with the blank control group, the proportion of PG cells increased at G0/ G1 and S phases (P < 0.05) and decreased at G2/M phase (P < 0.01) in the LS group; The proportion of PG cells increased at G2/M and S phases (P < 0.05, P < 0.01) and decreased at G0/G1 phase (P < 0.01) in the LS plus cisplatin group as well as the cisplatin group. Compared with the LS group, the proportion of PG cells increased at G2/M and S phases (P < 0.05, P < 0.01) and decreased at G0/G1 phase (P < 0.01) in the LS plus cisplatin group as well as the cisplatin group. There was no statistical difference in PG cells at each phase between the cisplatin group and the LS plus cisplatin group (P > 0.05). The expression of P16 and Rb1 mRNA increased in the LS group, when compared with the blank control group. They also increased in the cisplatin group and the LS plus cisplatin group, higher than that of the LS group (P < 0.05). There was no statistical difference in the expression of P16 and Rb1 mRNA between the cisplatin group and the LS plus cisplatin group (P > 0.05).

CONCLUSIONLS containing serum induced PG cell apoptosis by up-regulating the mRNA transcription levels of P16 and Rb1, thus resulting in PG cell arrest at G0/G1 and S phases, which was different from the manner of cisplatin (achieved by arresting PG cells at G2/M and S phases through regulating cyclinB1 mRNA transcription).