ABSTRACT
<p><b>OBJECTIVE</b>To study the methylation changes in promoter CpG islands induced by low-dose X-ray radiation (LDR).</p><p><b>METHODS</b>Twenty male BALB/c mice were randomly divided into control and fractionated radiation group exposed to 6 MV X-ray for 10 days (0.05 Gy/day). All the mice were sacrificed 2 h after the last radiation on day 10, and blood samples were collected for detecting DNA methylation changes using Roche-NimbleGen mouse DNA methylation 3×720K Promoter Plus CpG Island Array. MeDIP-qPCR was used to further validate the methylation status of specific genes.</p><p><b>RESULTS</b>A total of 811 genes were found to show specific hypermethylation in fractional radiation group as compared with the control group, involving almost all the main biological processes by GO analysis. Eight candidate genes (Rad23b, Tdg, Ccnd1, Ddit3, Llgl1, Rasl11a, Tbx2, and Slc6a15) were confirmed to be hypermethylated in LDR samples by MeDIP-qPCR, consistent with the results of the methylation chip study.</p><p><b>CONCLUSION</b>LDR induces promoter hypermethylation on specific genes, which may contribute to radiation-induced pathogenesis.</p>
Subject(s)
Animals , Male , Mice , CpG Islands , Radiation Effects , DNA Methylation , Dose-Response Relationship, Radiation , Genome , Mice, Inbred BALB C , X-RaysABSTRACT
Objective To investigate the role of epigallocatechin gallate ( EGCG) in reversing the CpG island methylation of Rad23b and Ddit3 gene promoter and its mRNA expression induced by 0?5 Gy X-rays. Methods Thirty BALB/c male mice were randomly divided into 6 groups: control group, irradiation group, low/high dose of EGCG group, low/high dose of EGCG with irradiation group. For the irradiation group, mice were fractionally exposed with 6 MV X-rays for 10 d (0?05 Gy/d × 10 d). 2 hours after the final irradiation, all mice were killed and such tissues as blood, kidney, liver, spleen, brain, and lung were collected. Methylation and expression levels of Rad23b and Ddit3 were measured by bisulfate sequencing primers ( BSP) and Real-time PCR, respectively. Results Compare to the control group, Rad23b was hypermethylated in PBMC, liver, spleen, brain and lung (t= -20?19, -14?80, -12?05,-28?42, -12?58, P<0?05) in the irradiation group. Meanwhile, its mRNA expression level was down-regulated in PBMC, liver, brain and lung (t=25?25, 17?43, 11?53, 22?85, P<0?05). Similarly, a significant hypermethylation change of Ddit3 was observed in PBMC, liver and lung after irradiation ( t=-52?89, -20?31, -3?85, P<0?05) so that the mRNA expression of Ddit3 decreased in PBMC and liver ( t = 11?89, 16?52, P < 0?05 ). Compared to the irradiation group, EGCG with different concentrations of 10, 20 mg/kg significantly reduced the methylation level of Rad23b and Ddit3 ( t =-13?39-7?99, P<0?05), and induced re-expression of mRNA (t= -34?02 - -2?89, P<0?05). This change was more notable in the irradiation group with the high dose of EGCG. Conclusions As a natural drug, EGCG may play an important role in affecting DNA methylation and hence protects DNA from radiation damage.
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Objective The invasion and metastasis of colon cancer often leads to treatment failure and mortality in patients . Our research is to investigate the influence of FoxM 1 to malignant human colon cancer line . Methods In two human colon cancer lines, the protein and mRNA expression levels of FoxM 1 were analyzed with the application of RT-PCR and Western blot , from which high-expressed HT-29 and low-expressed HCT-116 were determined.The expression of FoxM1 was down-regulated by RNA interfering in HT-29 and up-regulated by constructing overexpression transgenic line in HCT-116.The proliferation of the above cells was assayed by healing method;while the metastasis and invasion ability were examined by Transwell chamber assay . Results Two colon cancer lines were selected with high-expression or low-expression of FoxM1 separately named HT-29 and HCT-116.Application of PEX-2-FoxM1 raised after HCT-116 cells express FoxM1, cell scratches in HCT-116 experimetal group ([70.92 ±1.48]%) compared with HCT-116 control group([16.92 ±4.05]%)and HCT-116 blank control group([16.66 ±2.63]%) will markedly enhance its capabil-ity of healing (P<0.05), Transwell Chambers in membrane cells in HCT-116 experimetal group (186.0 ±6.8) compared with HCT-116 control group(42.0 ±2.0) and HCT-116 blank control grou (37.0 ± 2.2)was increased (P<0.05).On the other hand, the applied pG-PH-shFoxM1 can reduce FoxM1 expression in HT-29 cell, cell scrat-ches healing ability in HT-29 experimetal group ( [ 10 .37 ± 3.86]%) compared with HT-29 control group([34.63 ±2.35]%)and HT-29 blank control group([67.36 ±2.61]%) decreased significantly (P<0.05), Transwell Chambers in membrane cells in HT-29 experimetal group (53.0 ±1.8)compared with HT-29 control group(95.0 ±2.2)and HT-29 blank control grou(118.0 ±4.0) was also reduced (P<0.05). Conclusion The expression of FoxM1 is in close relation to the invasion and metastasis of CRC .The fact that the siRNA interfering FoxM1 could effectively inhibit the proliferation, metastasis and invasion, suggesting FoxM1 could po-tentially be a new molecular target for inhibiting the proliferation of human colon cancer line .
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We achieved satisfactory results in preventing post-colostomy cutaneous complications by targeted nursing interference.This article summarizes the experience in nursing three colorectal carcinoma patients against such complications after colostomy,with an analysis of the common causes of stomy-related cutaneous complications.