Effect of Survivin Down-Regulation by Egr1-Survivin shRNA Combined with Radiotherapy on Radiosensitivity of Esophageal Squamous Carcinoma / Efecto de la Regulación Negativa de Survivina por shRNA de Egr1-Survivina Combinado con Radioterapia sobre la Radiosensibilidad del Carcinoma Escamoso de Esófago

SUMMARY: This study is to investigate the effect of survivin down-regulation by Egr1-survivin shRNA combined with radiotherapy on the apoptosis and radiosensitivity of esophageal squamous cell carcinoma ECA109 and KYSE150 cells. ECA109 and KYSE150 cells were transfected with Egr1-survivin shRNA, and then treated with radiotherapy. After 24 h, the mRNA and protein levels of Egr1-survivin were detected by qPCR and Western-Blot. Cell cycle and apoptosis were detected by flow cytometry. Western blot also detected levels of cleavaged Caspase 3 and Caspase 9. YM155 was used as a positive control to inhibit survivin expression. The levels of survivin mRNA and protein in ECA109 and KYSE150 cells treated with Egr1-survivin shRNA combined with radiotherapy were significantly lower than those of the blank control group, the empty vector control group, and, the YM155 + radiotherapy group (P<0.05). Meanwhile, after survivin down-regulation, the ratio of G2 to S phase of ECA109 and KYSE150 cells increased significantly, leading to significant G2 and S phase arrest. Additionally, apoptosis of ECA109 and KYSE150 cells increased significantly (P <0.01). Further, protein levels of cleavaged Caspase 3 and Caspase 9 significantly increased in Egr1-survivin shRNA combined with radiotherapy group. Egr1-survivin shRNA combined with radiotherapy can down-regulate survivin expression, which further increases the apoptosis, and enhances the radiosensitivity of ECA109 and KYSE150 cells.

Este estudio tuvo como objetivo investigar el efecto de la regulación negativa de survivina por el shRNA de Egr1-survivina combinado con radioterapia sobre la apoptosis y la radiosensibilidad del carcinoma de células escamosas de esófago Células ECA109 y KYSE150. Las células ECA109 y KYSE150 se transfectaron con shRNA de survivina Egr1 y luego se trataron con radioterapia. Después de 24 h, los niveles de ARNm y proteína de Egr1-survivina se detectaron mediante qPCR y Western-Blot. El ciclo celular y la apoptosis se detectaron mediante citometría de flujo. La transferencia Western también detectó niveles de Caspasa 3 y Caspasa 9 escindidas. Se usó YM155 como control positivo para inhibir la expresión de survivina. Los niveles de ARNm y proteína de survivina en células ECA109 y KYSE150 tratadas con shRNA de survivina Egr1 combinado con radioterapia fueron significativamente más bajos que los del grupo control en blanco, el grupo control de vector vacío y el grupo de radioterapia YM155 + (P <0,05). Mientras tanto, después de la regulación negativa de survivina, la proporción entre las fases G2 y S de las células ECA109 y KYSE150 aumentó significativamente, lo que llevó a una detención significativa de las fases G2 y S. Además, la apoptosis de las células ECA109 y KYSE150 aumentó significativamente (P <0,01). Además, los niveles de proteína de Caspasa 3 y Caspasa 9 escindidas aumentaron significativamente en el shRNA de Egr1- survivina combinado con el grupo de radioterapia. El shRNA de survivina de Egr1 combinado con radioterapia puede regular negativamente la expresión de survivina, lo que aumenta aún más la apoptosis y mejora la radiosensibilidad de las células ECA109 y KYSE150.

Inhibitory effect of pshuttle-Egr-1-hSmac plasmid combined with X-ray irradiation on proliferation of breast cancer MDA-MB-435 cells / 吉林大学学报(医学版)

Objective To construct the pshuttle-Egr-1-hSmac plasmid and transfect human breast cancer MDA-MB-435 cells,and to observe its radiotherapy enhancing effect on tumor cells.Methods The empty vector pshuttle and pshuttle-Egr-1-hSmac plasmid were transfected into MDA-MB-435 cells by liposomal.At different time(4,8,12,24 and 48 h)after irradiation with 2.0 Gy X-ray and 24 h after irradiation with 0.5 -5.0 Gy,the total RNA and protein were collected and extracted from these cells to analyze the Smac mRNA and protein expression levels with RT-PCR and Western blotting methods. The cells were divided into control, pshuttle, pshuttle-Egr-1-hSmac,2.0 Gy irradiation group, pshuttle + 2.0 Gy irradiation and pshuttle-Egr-1-hSmac+2.0 Gy irradiation groups.MTT method was used to evaluate cell proliferation,and the cell survival ability was measured with clone formation assay;Annexin Ⅴ/PI double staining and PI single staining were used to examine the apoptosis and cell cycle of MDA-MB-435 cells. Results There was no Smac mRNA expression in MDA-MB-435 cells in control and pshuttle groups,but the Smac mRNA expression levels in MDA-MB-435 cells in pshuttle-Egr-1-hSmac plasmid group were gradually increased with the time prolongation, and reached the maximum at 24 and 48 h;the Smac mRNA expression levels in MDA-MB-435 cells were increased gradually 24 h after irradiation of 0.5 - 5.0 Gy X-ray with the increasing of irradiation doses, and reached the maximum after 2.0 and 5.0 Gy irradiation. The Smac protein expression levels in pshuttle-Egr-1-hSmac plasmid group were increased gradually with the time prolongation,and reached the maximum at 24 h.The Smac protein expression lervels were increased 24 h afer irradiation of 0,0.5,1.0,2.0 and 5.0 Gy X-ray,especially in 5.0 Gy group. The MTT results showed that the A490 values in 2.0 Gy,pshuttle+2.0 Gy and pshuttle-Egr-1-hSmac groups 24, 48,and 72 h after irradiation were lower than those in control group(P<0.01);the A490 values of MDA-MB-435 cells in pshuttle-Egr-1-hSmac group after 1.0-5.0 Gy X-ray irradiation were lower than those in 0 Gy group (P<0.05 or P<0.01);the survival fraction(SF)in pshuttle-Egr-1-hSmac group was lower than those in control group (P<0.01).The percentages of the cells at G0/G1 and S phase in pshuttle-Egr-1-hSmac group were lower than those in 2.0 Gy group(P<0.01),the percentage of the cells at G2/M phase was higher than that in 2.0 Gy group (P<0.01);the apoptotic rate of the cells in pshuttle-Egr-1-hSmac group was higher than that in 2.0 Gy group (P<0.01).Conclusion X-ray irradiation can significantly increase the Smac mRNA and protein expression levels in MDA-MB-435 cells transfected with pshuttle-Egr-1-hSmac plasmid,inhibit the cell survival rate,and induce G2/M arrest and apoptotic increasing;Smac gene combined with radiotherapy could significantly increase the radiosensitivity of breast cancer cells.

Enhanced Effects of TRAIL-endostatin-based Double-gene-radiotherapy on Suppressing Growth, Promoting Apoptosis and Inducing Cell Cycle Arrest in Vascular Endothelial Cells / 华中科技大学学报（医学）（英德文版）

This study examined the effects of TRAIL-endostatin-based gene-radiotherapy on cellular growth,apoptosis and cell cycle progression in human vascular endothelial cells ECV304 in vitro.The expression of TRAIL and endostatin protein in ECV304 cells was detected by ELISA after the transfection of recombinant plasmid pshuttle-Egrl-shTRAIL-shES and X-ray irradiation.Then MTT assay was used for determining the cellular proliferation,and flow cytometry (FCM) plus Annexin V and propidium iodide (PI) double-staining or PI single-staining were employed for the detection of apoptosis and cell cycle progression.The results showed that expression of TRAIL and endostatin protein exhibited a time- and dose-dependent change in ECV304 cells after pshuttle-Egrl-shTRAIL-shES transfection in conjunction with irradiation.In the TRAIL-endostatin-based single- or double-gene-radiotherapy,the cell viability declined in a time- and dose-dependent manner,the percentage of cells at G2/M phase and apoptotic rate was increased,and the percentage of cells at G0/G1 phase was lowered as compared with those receiving radiotherapy alone.Moreover,TRAIL-endostatin-based double-gene-radiotherapy demonstrated better effects on growth inhibition,promotion of apoptosis and induction of cell cycle arrest in ECV304 cells than single-gene-radiotherapy.

Anti-tumor effect of adenovirus-mediated suicide gene therapy under control of tumor-specific and radio-inducible chimeric promoter in combination with γ-ray irradiation in vivo / 中华放射医学与防护杂志

Objective To detect the selective inhibitory effects of irradiation plus adenovirusmediated horseradish peroxidase ( HRP)/indole-3-acetic acid (IAA) suicide gene system using tumorspecific and radio-inducible chimeric promoter on human hepatocellular carcinoma subcutaneously xenografted in nude mouse.MethodsRecombinant replicated-deficient adenovirus vector containing HRP gene and chimeric human telomerase reverse transcriptase (hTERT) promoter carrying 6 radioinducible CArG elements was constructed.A human subcutaneous transplanting hepatocellular carcinoma (MHCC97 cell line) model was treated with -γ-ray irradiation plus intra-tumor injections of adenoviral vector and intra-peritoneal injections of prodrug IAA.The change of tumor volume and tumor growth inhibiting rate,the survival time of nude mice,as well as histopathology of xenograft tumor and normal tissues were evaluated.Results Thirty one days after the treatment,the relative tumor volumes in the negative,adenovirus therapy,irradiation,and combination groups were 49.23 ± 4.55,27.71 :± 7.74,28.53 + 10.48 and 11.58 ± 3.23,respectively.There was a significantly statistical difference among them (F = 16.288,P ＜0.01 ).The inhibition effect in the combination group was strongest as compared with that in other groups,and its inhibition ratio was 76.5%.The survival period extended to 43 d in the combination group,which showed a significantly difference with that in the control group(x2 = 18.307 ,P ＜0.01 ).The area of tumors necrosis in the combination group was larger than that in the other groups,and the normal tissues showed no treatment-related toxic effect in all groups.However,multiple hepatocellular carcinoma metastases were observed in the liver in the control group,there were a few metastases in the monotherapy groups and no metastasis in the combination group.Conclusions Adenovirus-mediated suicide gene therapy plus radiotherapy dramatically could inhibit tumor growth and prolong median survival time.It might provide a promising therapeutic modality for hepatocellular carcinoma therapy.

Anti-tumor effect of pEgr-1-endostatin-TNF-α recombinant plasmid expression induced by ionizing radiation / 中华放射医学与防护杂志

Objective To study the anti-tumor effects of pEgr-1-endostatin-TNF-α generadiotherapy on mice bearing Lewis lung carcinoma, and to explore the mechanism involved. Methods 240 mice with Lewis lung carcinoma were randomly divided into four groups, including control group,irradiation group, liposome group, and liposome combined irradiation group. The plasmids packed by liposome were injected locally into the tumors of the mice, and the tumors of liposome combined irradiation group were irradiated with 10 Gy γ-rays 24 h later. The expression levels of TNF-α and endostatin in mouse serum were measured by ELISA. Then the tumor growth rates at different time were observed. Tumor angiogenesis density were estimated on frozen sections stained with CD31 by using the Chalkley counting method to vessel hot-spots. The tumor inhibition rates were also calculated. Results Radiation induced the expression of pEgr-1-endostatin-TNFα. The endostatin and TNF-α were expressed steadily for about 4 weeks. The highest levels of expression of the endostatin and TNF-α were (52. 64 ±4. 19)and( 12. 01 ±0. 87 ) ng/ml at 2 week. The expression levels of TNF-α and endostatin were higher in combined therapy group than those in other groups( F = 29. 726,P ＜ 0.05 ). Compared with the control group, the density of tumor angiogenesis were depressed [ (4.7 ± 0. 8 ) vs ( 10.0 ± 1. 2)/field, t = 14. 063, P ＜ 0.05 ] and tumor growth were significantly inhibited compared to the control group and irradiation group [ (5907. 2 ±78.6), (4653.4±32.8) and (763.5 ± 12.3) mm3, F= 16.415,P ＜0.05)]. Conclusions The expression of pEgr-1-endostatin-TNFα could be induced by irradiation in dose- and time-dependent manner. The effect of antitumor and angiogenesis inhibition may be more significant than irradition.

Anti-tumor effects of Egr-IFNγ gene therapy combined with 125I-UdR radionuclide therapy / 中华放射医学与防护杂志

Objective To explore the anti-tumor effects of Egr-IFNγ gene therapy combined with 125I-UdR radionuclide therapy in mice bearing H22 hepatocarcinoma and its mechanism. Methods The recombinant plasmid pcDNAEgr-IFNγ mixed with liposome was injected into tumor. 48 h later, 370 kBq 125I-UdR was injected into tumor. The tumor growth rates at different times were observed. After 3 d gene-radionuclide therapy, the concentration of IFNγ in cytoplasm of H22 cells and cytotoxic activities of splenic CTL of the mice in different groups were examined. Results The tumor growth rates of pcDNAEgr-IFNγ +125 I-UdR group were obviously lower than those of control group, 125I-UdR group and pcDNAEgr-1 +125I-UdR group 6-15 d after gene-radionuclide therapy. IFNγ protein was found in cytoplasm of H22 cells in PcDNAEgr-1FNγ+125I-UdR group after 3 d gene-radionuclide therapy. Cytotoxic activity of splenic CTL in pcDNAEgr-IFN7 + 125I-UdR group was significantly higher than that in the other groups (P<0.01). Conclusions The anti-tumor effects in vivo of pcDNAEgr-IFNγ gene therapy combined with 125I-UdR radionuclide therapy are better than those of 125I-UdR therapy.

Cloning of the Regulatory Sequence of Mouse Egr-1 Gene and Characteristics of Its Radiation-Inducible Property / 中国肿瘤生物治疗杂志

Egr-1 is a radiation-inducible transcription factor. It was demonstrated that the regulatory sequence in 5' flanking region of Egr-1 gene could confer the radiation inducibility upon a tumoricidal gene to which it was linked, and was consequently used in experiments on the gene-radiotherapy to tumor. As a first step to test the possibility, we have isolated the 445 bp-long regulatory sequence of Egr-1 gene from BALB/c mouse gcnomic DNA with PCR method. Sequence analysis confirmed that nucleotide sequence of this cloned fragment was identical with one reported previously with only one base difference in A to G substitution at residue - 392, and had six CC( A + T)6GG domains which were essential to the radiation-inducible property of Egr-1 gene. This fragment then was inserted into the Mlu I-Bgl II site of pGL3, a reporter vector containing luciferase gene. The constructs were used to transfect mouse malignant melanoma cells (B16) to characterize the regulatory function of this CC ( A + T)_(6)GG-rich sequence after exposure to r-radiation by a ~(60) Co source. The results indicate that the activity of luciferase in transfectant increases by 138% as compared with control levels, demonstrating that r-radiation inducibility of gene expression can be conferred by the regulatory sequence.