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Epidermal growth factor receptor 2 (HER2) is an oncogene involved in tumour genesis and progression. It is expressed in 7% of patients with colorectal cancer (CRC) and is associated with drug resistance of epidermal growth factor receptor monoclonal antibodies. With the emergence of the therapeutic dilemma of CRC and the survival benefits of targeting HER2 for patients with breast cancer and gastric cancer, the significance of HER2 in CRC and the prognostic value of anti-HER2 therapy have been widely concerned, clinical researches on HER2-positive CRC have been continuously carried out. Currently, the diagnostic criteria for HER2 positive CRC have gradually been unified. HER2-targeting therapies such as monoclonal antibodies, tyrosine kinase inhibitors, antibody-drug coupling and HER2-related immunotherapy alone or in combination have shown good efficacy and brought significant survival benefits for HER2 positive CRC. This paper reviews the research progress of HER2 in CRC.
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Objective: To obtain the conditionally replicative adenovirus with triple-targeting Smac overexpression using gene recombination technology, and to explore its effects on the apoptosis and cell cycle progression of MDA-MB-231 cells. Methods: The triple-targeting Smac overexpression vector pShuttle-Egrl-Smac-HRE-hTERT-ElA-ElBp-ElB55K was constructed by gene recombination technology, which was recombined with the skeleton vector pAdEasy in the BJ5183 bacteria (AdEasy-l +) to obtain the conditionally replicative adenovirus CRAd. pE-Smac. After the MDA-MB-231 cells were infected with CRAd. pE-Smac, the cancer cells were mimiced into hypoxic status with chemical reagent CoCl2, then control group, CRAd. pE-Smac group, hypoxia group and CRAd. pE-Smac + hypoxia group were set up; the cells were irradiated with 4 Gy X-rays, and each group was divided into nonirradiation group and irradiation group. The Smac protein expression was detected by Western blotting assay, the apoptotic rates and the percentages of cells at different phases were detected by flow cytometry. Results: The Western blotting results showed that the Smac protein expressions were increased after infection of CRAd. pE-Smac, hypoxia and 4 Gy irradiation, especially in CRAd. pE-Smac + hypoxia+4 Gy irradiation group. The FCM results showed that the apoptotic rates in CARd. pE-Smac, hypoxia, CARd. pE-Smac + hypoxia group were increased compared with control group (P<0. 05 or P<0. 01), and the apoptotic rates of cells irradiated with 4 Gy were significantly increased compared with the unirradiated cells (P<0. 05 or P<0. 01), especially in CRAd. pE-Smac + hypoxia + 4 Gy irradiation group; the percentages of the cells at S and G2/M phases in irradiation groups were significantly increased (P<0. 05 or P<0. 01), which had the similar regularity with the apoptotic change. Conclusion: After the MDA-MB-231 cells are infected with the conditionally replicative adenovirus CRAd. pE-Smac and treated with hypoxia and irradiation, the triple-targeting Smac overexpression can be achieved, and it has the role of promoting the cancer cell apoptosis and inducing the G2/M arrest.
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Objective:To obtain the conditionally replicative adenovirus with triple-targeting Smac overexpression using gene recombination technology,and to explore its effects on the apoptosis and cell cycle progression of MDA-MB-231 cells.Methods:The triple-targeting Smac overexpression vector pShuttle-Egr1-Smac-HRE-hTERT-E1A-E1Bp-E1B55K was constructed by gene recombination technology,which was recombined with the skeleton vector pAdEasy in the BJ5183 bacteria (AdEasy-1+-) to obtain the conditionally replicative adenovirus CRAd.pE-Smac.After the MDA-MB-231 cells were infected with CRAd.pE-Smac,the cancer cells were mimiced into hypoxic status with chemical reagent CoCl2,then control group,CRAd.pE-Smac group,hypoxia group and CRAd.pE-Smac+-hypoxia group were set up;the cells were irradiated with 4 Gy X-rays,and each group was divided into nonirradiation group and irradiation group.The Smac protein expression was detected by Western blotting assay,the apoptotic rates and the percentages of cells at different phases were detected by flow cytometry.Results:The Western blotting results showed that the Smac protein expressions were increased after infection of CRAd.pE-Smac,hypoxia and 4 Gy irradiation,especially in CRAd.pE-Smac +hypoxia+4 Gy irradiation group.The FCM results showed that the apoptotic rates in CARd.pE-Smac,hypoxia,CARd.pE-Smac + hypoxia group were increased compared with control group (P＜0.05 or P＜0.01),and the apoptotic rates of cells irradiated with 4 Gy were significantly increased compared with the unirradiated cells (P＜0.05 or P＜0.01),especially in CRAd.pE-Smac + hypoxia + 4 Gy irradiation group;the percentages of the cells at S and G2/M phases in irradiation groups were significantly increased (P＜ 0.05 or P＜0.01),which had the similar regularity with the apoptotic change.Conclusion:After the MDA-MB-231 cells are infected with the conditionally replicative adenovirus CRAd.pE-Smac and treated with hypoxia and irradiation,the triple-targeting Smac overexpression can be achieved,and it has the role of promoting the cancer cell apoptosis and inducing the G2/M arrest.
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Objective:To explore the effect of ionizing radiation on apoptosis of lung cancer H460 cells after ATRX was silenced by RNAi and its mechanism.Methods:The lentivirus expression vectors targeting ATRX were transfected into the 293T cells,and the lung cancer H460 cells were infected with lentivirus twice,and the ATRX silenced cell model was obtained after puromycin positive screening,then they were named as sh-ATRX1-H460,sh-ATRX2-H460,and sh-ATRX3-H460 cells;the sh-control-H460 cells were regarded as control cells.The cells were divided into sh-control-H460 group and sh-ATRX3-H460 group,accroding to the silencing results and were irradiated by 0,2 and 8 Gy X-rays.The expression levels of ATRX,poly(ADP-ribose) polymerase 1(PARP1),and caspase-3 proteins were measured by Western blotting method;the apoptotic rate was measured by flow cytometry and AnnexinⅤ-FITC/PI kits.Results:The lung cancer cell model of sh-ATRX3-H460 silenced by ATRX was obtained successfully.After 2 and 8 Gy X-ray irradiation,compared with before irradiation,the expression level of ATRX protein in sh-control-H460 group was increased,while there was no expression of ATRX protein in sh-control-H460 group;compared with before irradiation,the apoptotic rates of cells in two groups were increased(P<0.05 or P<0.01);the apoptotic rate in sh-ATRX3-H460 group was significantly higher than that in sh-control-H460 group after 8 Gy X-ray irradiation (P<0.01).The expressions of cleaved PARP1 in the cells in both two groups after 2 Gy and 8 Gy X-ray irradiation were increased and showed similar rule.The expression level of procaspase-3 protein in sh-control-H460 group had little change,and it was increased significantly in sh-ATRX3-H460 group after 8 Gy X-ray irradiation.Conclusion:ATRX silencing can be achived by RNAi,then the silencing could increase the apoptosis induced by irradiation and its mechanism may be related to the PARP1-caspase-3 pathway.
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Objective To establish the MCF-7 cell models of Beclin 1 over-and low-expressions,and to detect the autophagic and apoptotic changes after 4 Gy irradiation,and to explore their molecular regulation mechanisms. Methods MCF-7,MCF-7 + 4Gy,MCF-7-Beclin 1 + 4Gy and MCF-7-Belcin 1 RNAi+ 4Gy groups were set up. Molecular biology method was used to construct Beclin 1 over-expression vector pcDNA3.1-Beclin 1,and to estabilish the Beclin 1 over- and low-expression cell models.After the cells were irradiated with 4 Gy, the autopahgic cell percentages were measured by fluorescence microscope with MDC staining, the apoptotic cell percentages were measured by FCM with AnnexinⅤ-FITC and PI staining,and the expressions of Beclin1,P53, Bcl-2 and Bax proteins were measured by Western blotting method.Results Compared with MCF-7 group,the autophagic and apoptotic cell percentages in MCF-7+4 Gy,MCF-7 Beclin 1 +4 Gy and MCF-7-Beclin 1 RNAi+4 Gy groups were significantly increased (P <0.05 or P <0.001 ),especially in MCF-7 Beclin 1+4 Gy group which was significantly higher than those in MCF-7 + 4 Gy (P < 0.05);while there was significant difference in the necrotic cell percentages between various groups. After 4 Gy irradiation, compared with MCF-7 group, the expression levels of Beclin 1,P53 and Bax proteins in MCF-7 + 4 Gy and MCF-7-Beclin 1 + 4 Gy groups were increased,but the expression levels of Bcl-2 protein were decreased,especially in MCF-7-Beclin 1 + 4 Gy group. Conclusion The MCF-7 cell models of Beclin 1 over-and low-expressions are successfully established,and ionizing radiation could induce the autophagy and apoptosis of MCF-7 cells,which is more obvious in Beclin 1 over-expression MCF-7 cells.Beclin 1 can activate P53,inhibit Bcl-2 and activate Bax,which forms the regulation of autophagy and apoptosis by P53 .
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Objective To investigate the influence of truncated apoptosis inducing factor (AIFΔ1-480 ) on the proliferation and invasion of MCF-7 cells,and to clarify the possibility of promoting cancer gene-radiotherapy. Methods The human breast cancer MCF-7 cells were transfected with AIFΔ1-480 recombinant expression vector pcDNA3.1-Egr-1-AIFΔ1-480 (pE-AIFΔ1-480 )mediated by Egr-1;24 h after 2 Gy X-ray irradiation,MTT assay and Transwell invasion assay were performed to measure the changes of cell proliferation and invasion.The MCF-7 cells were diveded into normal control,pcDNA3.1,pE-AIFΔ1-480 ,2 Gy irradiation and pE-AIFΔ1-480+ 2 Gy irradiation groups.Results After transfection and 2 Gy X-ray irradiation,the cells proliferated very fast in normal control, pcDNA3.1 and pE-AIFΔ1-480 groups, and the proliferation regularity was similar. Compared with normal control group,the cell proliferation abilities were significantly decreased in 2 Gy irradiation and pE-AIFΔ1-480 + 2 Gy irradiation groups (P<0.05 ), and it was more obvious in pE-AIFΔ1-480 + 2 Gy irradiation group, and it was significant lower than that in 2 Gy irradiation group (P<0.05).The number of the cells permeating membrane was basically same in normal control,pcDNA3.1 and pE-AIFΔ1-480 groups;compared with normal control group,they were significantly decreased in 2 Gy irradiation and pE-AIFΔ1-480+ 2 Gy irradiation groups(P<0.05 or P<0.01);and it was more significant in pE-AIFΔ1-480+ 2 Gy irradiation group than that in 2 Gy irradiation group (P<0.01). Conclusion AIFΔ1-480 and ionizing radiation could inhibit the proliferation and invasion of human breast cancer MCF-7 cells,both of them have a synergistic effect,and Egr-1 promoter can enhance the suppression effect under radiation conditions.
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Objective To detect the inhibiting effects of ionizing radiation combined with inhibitors or inducer of autophagy and apoptosis on MCF7 cell line,and to provide the evidence for human breast cancer therapy radiation.Methods MCF7 cells were exposed to X-rays and randomly divided into 4 groups,including 0 Gy,4 Gy,4 Gy+rapamycin,4 Gy+3-MA,and 4 Gy+z-VAD-fmk groups,including 0 Gy,4 Gy,4 Gy+rapamycin,4 Gy+3-MA,and 4 Gy+z-VAD-fmk groups,respectively.The growth doubling time was calculated by MTT method.The specific protein expressions of LC3 autophagy and beclinl were detected by using Western blot and the difference of Drotein contents wasLC3 autophagy and beclinl were detected by using Western blot and the difference of Drotein contents was compared.The percentage of apoptosis of MCF7 cells was measured by flow cytometry (FCM).Resuits The growth doubling time of MCF7 cells in 4 Gy group wag longer than that in O Gy group(t=4.41,P<O.05),but shorter than that in 4 Gy+rapamycin group(t=4.35,P<0.05).Compared to 4 Gy+rapamycin group,both of the growth doubling time in 4 Gy+3-MA and 4 Gy+z-VAD-fmk groups were shorter(t=4.32,P<O.05).The expressions of beclinl and LC3-Ⅱ proteins in 4 Gy+rapamycin group were the highest,while those in 4 Gy+3-MA group the lowest.Except for 4 Gy+3-MA and 4 Gv+z-VAD-fmk groups,there were significant differences among the other groups in two protein expressions(t=3.9 1-4.78,P<0.05).Conclusions Ionizing radiation could induce MCF7 cell autophagy,ptomote the apoptosis of tumor ceils in combination with autophagy inducer.Ionizing radiation combined with autophagy inhibitor might inhibit the development of autophagy,and delay the apoptosis of tumor cells.