Objective: To study the mechanism of regulating the growth of the lung cancer stem cells containing by Xihuang pill drug serum. Method: Ten rabbits were divided5 groups

the therapeutic dose of 32

16

8 g·kg-1·d-1 ig of Xihuang pill liquid and 7.5 mg·kg-1·d-1 ip of cyclophosphamide(CTX) were given. Drug serum of rabbits were prepared. Side population cells (SP cells) of the human lung adenocarcinoma cells(LAC) were sorted by Fluorescence-activated cell sorting assay(FACS). Fifty C57BL/6 mice were divided model group

Xihuang pill low

middle and high-dose group

and the CTX group. SP cells were regulated to 1×107/mL and sc

Xihuang pill liquid (32

16

8 g·kg-1·d-1

ig) and CTX(7.5 mg·kg-1·d-1

ip) were given lasted 2 weeks. Then the tumors were weighted for calculating the tumor growth inhibition rate. SP cells were regulated to 2×106/mL and put into 5 culture bottles

divided into control group

Xihuang pill low

middle and high-dose groups

and the CTX group. Drug serum of groups were put into corresponding SP cells(drug serum occupies 70% of cell medium). The cell cycle was analyzed by flow cytometry (FCM). In the same way

SP cells were affected by drug serum of groups and the expression of Cyclin D1 mRNA and protein was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Result: The Xihuang pill middle

high-dose group and CTX group significantly inhibited tumors of all groups

compared with the control group (P<0.01). Cells in G1 phase of the Xihuang pill middle

high-dose group and CTX group increased

cells in G2 phase and S phase of the Xihuang pill middle

high-dose group and CTX group decreased (P<0.05). The Xihuang pill middle and high-dose group could regulate down the expression of Cyclin D1 mRNA and protein compared with the model group (P<0.05

P<0.01). Conclusion: Xihuang pill could down-regulate the expression of Cyclin D1of lung cancer stem cells. It could prevent their G1 period turning into S period

so as to block the growth of lung cancer cells.