Impact of adenomatous polyposis coli (APC) tumor supressor gene in human colon cancer cell lines on cell cycle arrest by apigenin

Abstract

This research assessed the importance of the adenomatous polyposis coli (APC) tumor suppressor mutation in the ability of apigenin to induce cell cycle arrest using HT29-APC cells, which contain inducible wild-type APC under the metallothionein promoter. HT29-GAL cells, containing beta-galactosidase (GAL), were included as control. Treatment with apigenin (0, 20, 40, 60, and 80 microM) for 48 h resulted in reduction in the cell number (P < 0.05) concurrent with flow cytometry results showing a dose-dependent accumulation of cells in the G2/M phase in both HT29-APC and HT29-GAL cells without ZnCl(2) treatment. Flow cytometric analysis showed an increase (P < 0.05) in the percentage of cells in G2/M when HT29-APC cells were treated with 80 microM apigenin for 120 h. This increase was not present in HT29-APC cells when treated with both 80 microM apigenin and 100 microM ZnCl(2) for 120 h. Western blot analysis verified the induction of APC protein expression in ZnCl(2)-treated HT29-APC cells but not in ZnCl(2)-treated HT29-GAL cells. Apigenin plus ZnCl(2) treatment increased the expression of APC protein in HT29-APC cells by 50 fold above expression observed with ZnCl(2) alone. Upon induction of the APC gene with ZnCl(2) in HT29-APC cells, the percentage of apoptotic cells increased significantly (P< 0.05) after 120-h treatment. Additionally, apigenin treatment (80 microM) further increased the percentage of apopototic HT29-APC following ZnCl(2) treatment to induce wild-type APC expression. These results suggest that APC dysfunction may be critical for apigenin to induce cell cycle arrest in human colon cancer cell lines and furthermore, apigenin enhances APC expression and apoptosis in cells with wild-type APC.

Evaluation of the Effects of the Flavonoid Apigenin on Apoptotic Pathway Gene Expression on the Colon Cancer Cell Line (HT29)

“…43,44 Although many flavonoid members with apoptotic effects on the HT29 cell line have been studied, [45][46][47][48][49] the number of those tackling apigenin administration to HT29 cells remains limited. [48][49][50][51][52][53][54][55] Four of these studies evaluated the effect of apigenin on cell viability. Treatment with 40lM apigenin for 24 hours; 49 60 lM and 80lM apigenin for 48 hours; 43 40 lM, 60 lM, and 80 lM apigenin for 48 hours; 54 and 130.6.lM apigenin for 72 hours 55 all resulted in statistically significant reductions in cell viability.…”

Molecular mechanisms for chemoprevention of colorectal cancer by natural dietary compounds

“…Curcumin has also been reported to inhibit cell invasion by downregulation of COX-2 and MMP-2 expression and inhibit colon cancer cell growth through suppressing EGFR gene expression and modulating Akt/mTOR signaling in CRC cells [39][40][41]. In another study, curcumin has been found to Suppresses the phosphorylation of EGFR and downstream signaling in colon carcinoma cells [19] Induces apoptosis through upregulation of p53, p21, and AMPK signaling [20] Reduces b-catenin/Tcf transcriptional activity, induces G2/M cell-cycle arrest through decreasing gene expression of cyclin D1 and survivin [21] Apigenin Induces apoptosis by enhancing APC protein expression in colon cancer cells [22] Reduces AOM-induced ACF number and increases apoptosis of luminal surface colonocytes [23] 5-Hydroxy-6,7,8,4…”

“…Apigenin, present in parsley and celery, evokes its inhibitory effect on carcinogenesis through the induction of apoptosis in human colon cancer cells and reduces azoxymethane (AOM)-induced ACF number in rats [22,23].…”

Apigenin suppresses the growth of colorectal cancer xenografts via phosphorylation and up-regulated FADD expression

“…Pre-treatment with apigenin induces the apoptosis of HCT-116 colon cancer cells (5) and inhibits the growth of colon carcinoma cell lines, including SW480, HT-29 and Caco-2 (6). A previous study showed that apigenin enhanced apoptosis in HT29 cells with wild-type adenomatous polyposis coli (7). In vivo studies showed that apigenin moderately reduces azoxymethane-induced colon carcinogenesis and inhibits the growth of colorectal cancer (8).…”