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RASSF10 suppresses colorectal cancer growth by activating P53 signaling and sensitizes colorectal cancer cell to docetaxel.

Guo J, Yang Y, Yang Y, Linghu E, Zhan Q, Brock MV, Herman JG, Zhang B, Guo M - Oncotarget (2015)

Bottom Line: RASSF10 has previously been reported to be frequently methylated in a number of malignancies.RASSF10 was methylated in 60.7% (54/89) of primary colorectal cancers and was positively associated with tumor stage (p < 0.05) and metastasis (p < 0.05).RASSF10 was shown to activate P53 signaling in RKO and HCT116 cells after UV exposure, and sensitized these cells to docetaxel.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology & Hepatology, Chinese PLA General Hospital, Beijing 100853, P.R.China.

ABSTRACT
RASSF10 has previously been reported to be frequently methylated in a number of malignancies. To understand the importance of RASSF10 inactivation in colorectal carcinogenesis, eight colorectal cancer cell lines, 89 cases of primary colorectal cancer and 5 cases of normal colorectal mucosa were examined. Methylation specific PCR, western blot, siRNA, gene expression array and xenograft mice were employed. The expression of RASSF10 was regulated by promoter regional methylation in colorectal cancer cells. RASSF10 was methylated in 60.7% (54/89) of primary colorectal cancers and was positively associated with tumor stage (p < 0.05) and metastasis (p < 0.05). Restoration of RASSF10 led to inhibition of colorectal cancer cell proliferation in vitro and in vivo and increased apoptosis. Gene expression arrays discovered RASSF10 inhibition of MDM2 expression as a mediator of these effects, which was confirmed with RT-PCR and western blot. RASSF10 was shown to activate P53 signaling in RKO and HCT116 cells after UV exposure, and sensitized these cells to docetaxel. In conclusion, our study demonstrates RASSF10 is frequently methylated in human colorectal cancer leading to loss of expression. RASSF10 normally suppresses human colorectal cancer growth by activating P53 signaling in colorectal cancer, and restored expression sensitizes colorectal cancer to docetaxel.

No MeSH data available.


Related in: MedlinePlus

RASSF10 expression alters cell cycle regulations and sensitivity of colorectal cancer cells to docetaxel(A) Cell phase distribution in RASSF10 unexpressed and expressed RKO and HCT116 cells analysed by flow cytometry. *: p < 0.05. (B) The expression of RASSF10, CDC2 and cyclin B1 detected by western blot in RASSF10 unexpressed and expressed RKO and HCT116 cells. Actin: internal control. (C) The cell viability in RASSF10 unexpressed and re-expressed RKO and HCT116 cells after docetaxel treatment. IC50: the half maximal inhibitory concentration Points: three independent experiments. *: P < 0.05.
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Figure 3: RASSF10 expression alters cell cycle regulations and sensitivity of colorectal cancer cells to docetaxel(A) Cell phase distribution in RASSF10 unexpressed and expressed RKO and HCT116 cells analysed by flow cytometry. *: p < 0.05. (B) The expression of RASSF10, CDC2 and cyclin B1 detected by western blot in RASSF10 unexpressed and expressed RKO and HCT116 cells. Actin: internal control. (C) The cell viability in RASSF10 unexpressed and re-expressed RKO and HCT116 cells after docetaxel treatment. IC50: the half maximal inhibitory concentration Points: three independent experiments. *: P < 0.05.

Mentions: To further examine growth inhibition, we determined cell cycle distribution before and after restoration of RASSF10 expression in RKO cells with the following findings: 51.8 ± 2.3% vs 42.4 ± 0.7% (P < 0.05) in G0/1 phase, 37.9 ± 1.6% vs 38.1 ± 0.5% in S phase and 10.4 ± 1.8% vs 19.5 ± 1.2% (P < 0.05) in G2/M phase. The cell phase distribution before and after restoration of RASSF10 expression in HCT116 cells was as follows: 43.0 ± 5.7% vs 35.7 ± 4.4% (P < 0.05) in G0/1 phase, 44.2 ± 5.7% vs 41.6 ± 1.8% in S phase and 12.8 ± 0.1% vs 22.7 ± 2.7% (P < 0.05) in G2/M phase. This suggested that G0/1 phase was reduced and G2/M phase was increased in RKO and HCT116 cells (Fig. 3A), suggesting G2/M checkpoint inhibition. To further validate the effect of RASSF10 on G2/M check point, the expression of cdc-2 and cyclin B1, important G2/M check point regulators, was determined using western blot. The expression of cdc-2 and cyclin B1 was reduced after re-expression of RASSF10 in RKO and HCT116 cells (Fig. 3B), providing a mechanism by which RASSF10 induces G2/M arrest in colorectal cancer.


RASSF10 suppresses colorectal cancer growth by activating P53 signaling and sensitizes colorectal cancer cell to docetaxel.

Guo J, Yang Y, Yang Y, Linghu E, Zhan Q, Brock MV, Herman JG, Zhang B, Guo M - Oncotarget (2015)

RASSF10 expression alters cell cycle regulations and sensitivity of colorectal cancer cells to docetaxel(A) Cell phase distribution in RASSF10 unexpressed and expressed RKO and HCT116 cells analysed by flow cytometry. *: p < 0.05. (B) The expression of RASSF10, CDC2 and cyclin B1 detected by western blot in RASSF10 unexpressed and expressed RKO and HCT116 cells. Actin: internal control. (C) The cell viability in RASSF10 unexpressed and re-expressed RKO and HCT116 cells after docetaxel treatment. IC50: the half maximal inhibitory concentration Points: three independent experiments. *: P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414183&req=5

Figure 3: RASSF10 expression alters cell cycle regulations and sensitivity of colorectal cancer cells to docetaxel(A) Cell phase distribution in RASSF10 unexpressed and expressed RKO and HCT116 cells analysed by flow cytometry. *: p < 0.05. (B) The expression of RASSF10, CDC2 and cyclin B1 detected by western blot in RASSF10 unexpressed and expressed RKO and HCT116 cells. Actin: internal control. (C) The cell viability in RASSF10 unexpressed and re-expressed RKO and HCT116 cells after docetaxel treatment. IC50: the half maximal inhibitory concentration Points: three independent experiments. *: P < 0.05.
Mentions: To further examine growth inhibition, we determined cell cycle distribution before and after restoration of RASSF10 expression in RKO cells with the following findings: 51.8 ± 2.3% vs 42.4 ± 0.7% (P < 0.05) in G0/1 phase, 37.9 ± 1.6% vs 38.1 ± 0.5% in S phase and 10.4 ± 1.8% vs 19.5 ± 1.2% (P < 0.05) in G2/M phase. The cell phase distribution before and after restoration of RASSF10 expression in HCT116 cells was as follows: 43.0 ± 5.7% vs 35.7 ± 4.4% (P < 0.05) in G0/1 phase, 44.2 ± 5.7% vs 41.6 ± 1.8% in S phase and 12.8 ± 0.1% vs 22.7 ± 2.7% (P < 0.05) in G2/M phase. This suggested that G0/1 phase was reduced and G2/M phase was increased in RKO and HCT116 cells (Fig. 3A), suggesting G2/M checkpoint inhibition. To further validate the effect of RASSF10 on G2/M check point, the expression of cdc-2 and cyclin B1, important G2/M check point regulators, was determined using western blot. The expression of cdc-2 and cyclin B1 was reduced after re-expression of RASSF10 in RKO and HCT116 cells (Fig. 3B), providing a mechanism by which RASSF10 induces G2/M arrest in colorectal cancer.

Bottom Line: RASSF10 has previously been reported to be frequently methylated in a number of malignancies.RASSF10 was methylated in 60.7% (54/89) of primary colorectal cancers and was positively associated with tumor stage (p < 0.05) and metastasis (p < 0.05).RASSF10 was shown to activate P53 signaling in RKO and HCT116 cells after UV exposure, and sensitized these cells to docetaxel.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology & Hepatology, Chinese PLA General Hospital, Beijing 100853, P.R.China.

ABSTRACT
RASSF10 has previously been reported to be frequently methylated in a number of malignancies. To understand the importance of RASSF10 inactivation in colorectal carcinogenesis, eight colorectal cancer cell lines, 89 cases of primary colorectal cancer and 5 cases of normal colorectal mucosa were examined. Methylation specific PCR, western blot, siRNA, gene expression array and xenograft mice were employed. The expression of RASSF10 was regulated by promoter regional methylation in colorectal cancer cells. RASSF10 was methylated in 60.7% (54/89) of primary colorectal cancers and was positively associated with tumor stage (p < 0.05) and metastasis (p < 0.05). Restoration of RASSF10 led to inhibition of colorectal cancer cell proliferation in vitro and in vivo and increased apoptosis. Gene expression arrays discovered RASSF10 inhibition of MDM2 expression as a mediator of these effects, which was confirmed with RT-PCR and western blot. RASSF10 was shown to activate P53 signaling in RKO and HCT116 cells after UV exposure, and sensitized these cells to docetaxel. In conclusion, our study demonstrates RASSF10 is frequently methylated in human colorectal cancer leading to loss of expression. RASSF10 normally suppresses human colorectal cancer growth by activating P53 signaling in colorectal cancer, and restored expression sensitizes colorectal cancer to docetaxel.

No MeSH data available.


Related in: MedlinePlus