TITLE:
Role of p38 Signaling Pathway in Pentagastrin-Regulated Cell Proliferation of Colorectal Carcinoma Cell Line HT-29
AUTHORS:
Jiading Mao, Pei Wu, Jian Wu, Liang Tao, Ping Wu, Guang Yang, Wenwen Guo, Jun Wang
KEYWORDS:
Gastrin, p38, Proglumide, Proliferation Index, Apoptosis Rate, MAPK, Colorectal Carcinoma
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.7 No.6,
June
14,
2016
ABSTRACT: Objective: To investigate
the effects and mechanisms of p38 signaling pathway in pentagastrin-regulated cell
proliferation of colorectal carcinoma cell line HT-29. Methods: HT-29 cell line
of colorectal carcinoma was in vitro incubated
and divided into the control group, pentagastrin group, proglumide group, and pentagastrin
+ proglumide group. MTT reduction assay was performed to detect the proliferation
status of HT-29 cell line and determine the optimal dosage of pentagastrin and proglumide.
Annexin V-fluorescein isothiocyanate flow cytometry was used to detect the proliferation
index (PI) and apoptosis rate (AR) of HT-29 cells. Reverse transcriptase polymerase
chain reaction was performed to detect the mRNA expression of the pentagastrin receptor/cholecystokinin-B
receptor (CCK-BR) and p38. The protein and phosphorylation levels of p38 were estimated
by western blotting. Results: RT-PCR detection showed that CCK-BR mRNA was expressed
in the HT-29 cell line. Pentagatrin improved HT-29 cell proliferation in dosage
of 6.25 - 100 mg/L, and the optimal dosage of pentagastrin was 25.0 mg/L. Proglumide
had no significant effect on the proliferation of HT-29 cells, but significantly
inhibited the proliferation of HT-29 cells stimulated by pentagastrin when the dosage
of proglumide was 8.0 - 128.0 mg/L, and the optimal dosage was 32.0 mg/L. The AR
in the pentagastrin group was significantly lower than that in the control group
and in the pentagastrin + proglumide group. The PI in the pentagastrin group was
significantly higher than that in the control group and in the pentagastrin + proglumide
group. P38 phosphorylation level in the pentagastrin group was significantly lower
than that in the control group, and in the pentagastrin + proglumide group. There
were no significant differences in the mRNA and protein expression of p38 in the
control, pentagastrin, proglumide and pentagastrin + proglumide groups. Conclusion:
Pentagastrin can improve proliferation of the CRC cell line HT-29 and inhibit apoptosis
via the p38 signal transduction pathway. This mechanism may be associated with suppressed
p38 protein phosphorylation level due to inhibition of proglumide, a gastrin receptor
antagonist.