Objective:

2

To explore the proliferation inhibitory effect of quinones from

Blaps rynchopetera

defense secretion on colorectal tumor cell lines.

Methods:

2

Human colorectal cancer cell HT-29

human colorectal adenocarcinoma cell Caco-2 and normal human colon epithelial cell CCD841 were chosen for the evaluation of inhibitory activity of the main quinones of

B. rynchopetera

defense secretion

including methyl p-benzoquinone (MBQ)

ethyl p-benzoquinone (EBQ)

and methyl hydroquinone (MHQ)

through methyl thiazolyl tetrazolium assay. The tumor-related factors

cell cycles

related gene expressions and protein levels were detected by enzyme-linked immunosorbent assy

flow cytometry

RT-polymerase chain reaction and Western blot

respectively.

Results:

2

MBQ

EBQ

and MHQ could significantly inhibit the proliferation of Caco-2

with half maximal inhibitory concentration (IC 50 ) values of 7.04±0.88

10.92±0.32

9.35±0.83

HT-29

with IC 50 values of 14.90±2.71

20.50±6.37

13.90±1.30

and CCD841

with IC 50 values of 11.40±0.68

7.02±0.44 and 7.83±0.05 μg/mL

respectively. Tested quinones can reduce the expression of tumor-related factors tumor necrosis factor α

interleukin (IL)-10

and IL-6 in HT-29 cells

selectively promote apoptosis

and regulate the cell cycle which can reduce the proportion of cells in the G 1 phase and increase the proportion of the S phase. Meanwhile

tested quinones could up-regulate mRNA and protein expression of GSK-3β and APC

while down-regulate that of β-catenin

Frizzled1

c-Myc

and CyclinD1 in the Wnt/β-catenin pathway of HT-29 cells.

Conclusion:

2

Quinones from

B. rynchopetera

defense secretion could inhibit the proliferation of colorectal tumor cells and reduce the expression of related factors

which would be functioned by regulating cell cycle

selectively promoting apoptosis

and affecting Wnt/β-catenin pathway-related mRNA and protein expressions.