The individual variability should be considered in precision medicine-prevention and treatment strategies.Medical research using genomics, proteomics, metabolomics, systems analyses, and other modern tools has made big progress.In 2002, the members of the Complex-Trait Consortium proposed to develop a new mouse genetics resource called the Collaborative Cross (CC).The CC is a genetic reference panel of recombinant inbred lines of mice, designed for the dissection of complex traits and gene networks.It will provide a powerful measure for functional studies of biological networks, which will be essential to understand the intricacies of disease processes.

Objective To study the curative effect of XRCC2 gene silencing mediated by shRNA combined with radiation on human colonic trans?planted carcinoma in nude mice. Methods Colonic carcinoma T84 cells were transfered into BALB/c nude mice to establish a tumor xenograft mod?el in vivo. Mice were divided into three groups:control,shRNA?SC and shRNA?XRCC2 and exposed to X?ray radiation. The change of volume and weight of the xenografts were examined after receiving radiotherapy and the pathological analysis of tumor tissues were conducted. Results Tumor xenografts transfected with shRNA?XRCC2 in nude mice grew slowly. The xenograft volume in the shRNA?XRCC2 group was decreased significant?ly from day 12 to day 28 after radiotherapy compared with the control group(P<0.01). The xenograft weight in the shRNA?XRCC2 group was small?er than in the control group,with statistically significant difference(t=18.843,P<0.01). The inhibited rate of xenografts in the shRNA?XRCC2 group(56.25%),was markedly higher than that in the shRNA?SC group(4.69%). Pathological analysis of colonic transplanted carcinoma showed that nuclear atypia was not obvious,karyokinesis was decreased and small areas of necrosis were present in tumor xenografts treated with shRNA?XRCC2 transfection. Conclusion XRCC2 gene silencing combined with radiation has significant inhibition effect on colonic transplanted carcino?ma in nude mice.

Objective To investigate the effects of pulsed electromagnetic fields (PEMF) on homing and proliferation-related genes of mouse osteoblasts.Methods 9 week-old C57BL/6 mice were treated with PEMF (70 Hz,1 mT) for 4～5 weeks,while mice in control group didn't not receive PEMF.Bone marrow cells of femurs and tibias were flushed out,and the bones were minced and incubated at 37 ℃ with a type Ⅰ collagenase.Bone associated mononuclear cells (MNCs) were isolated via density centrifugation with Lymphoprep.Magnetic cell sorting was used before flow-cytometric sorting,and the ALCAM+Sca-1-cells were collected.The homing and proliferation-related genes expressed in ALCAM+Sca-1-cells were detected with high throughput microarray and RT-PCR.Results The expression of Jag1 and Ang-1 in mouse osteoblasts increased under the effects of PEMF.Conclusions PEMF may have regulation effects on HSC (hematopoietic stem cell) survival through modulating the homing and proliferationrelated genes in ALCAM+Sca-1-osteoblasts.

OBJECTIVETo investigate the inhibitory effect of resveratrol on interleukin-1β (IL-1β) production in mesenchymal stem cells (MSCs) exposed to radiation and the action mechanism of resveratrol.

METHODSMSCs were divided into blank control group, radiation group, shRNA interference group, and resveratrol groups. The resveratrol groups were given different doses of resveratrol (50, 100, and 200 µmol/L) before radiation. The secretion and expression of IL-1β was measured by enzyme-linked immunosorbent assay, Western blot, and RT-PCR.

RESULTSCompared with the radiation group, the resveratrol groups had significantly decreased extracellular secretion of IL-1β (t = 83.34, 24.48, and 12.52, P < 0.05 for all) and significantly decreased intracellular expression of IL-1β protein and mRNA (t = 8.695, 14.77, and 13.9, P < 0.05 for all). Compared with those given 200 µmol/L resveratrol alone before radiation, the MSCs treated by SIRT1 silencing and given 200 µmol/L resveratrol before radiation had significantly increased extracellular secretion of IL-1β (t = 18.57, P < 0.05) and significantly increased intracellular expression of IL-1β protein and mRNA (t = 10.24, P < 0.05).

CONCLUSIONResveratrol can significantly inhibit the production of IL-1β in MSCs exposed to radiation, and SIRT1 may play a key regulatory role in the process of inflammation induced by radiation.

Cells, Cultured ; Humans ; Interleukin-1beta ; metabolism ; Mesenchymal Stromal Cells ; drug effects ; metabolism ; radiation effects ; Radiation ; Radiation Dosage ; Stilbenes ; pharmacology

Objective To investigate the effect of radiation on the expressions of RANKL and OPG in osteoblasts in order to disclose the molecular mechanism of bone injury induced by ionizing radiation.Methods The osteoblasts were differentiated from MC3T3-E1 cells.After 2 or 4 Gy137 Cs γ-irradiation,the mRNA and protein expression levels of RANKL and OPG of osteoblast precursor and osteoblast were detected by real-time PCR and Western blot.Results The expressions of RANKL mRNA (t=5.41,P＜0.05)and protein(t=68.37,P＜0.01)were up-regulated after 4 Gy irradiation,while the expressions of OPG mRNA(t=5.20,7.02,P＜0.05)and protein(t=7.78,9.45,P＜0.05)were down-regulated after 2 and 4 Gy irradiation.Conclusions 2 and 4 Gy ionizing radiation alters RANKL/RANK/OPG pathway in osteoblasts,which may promote the osteoclast differentiation and maturation and hence promote bone resorption of osteoclasts.

Objective To evaluate the correlation between homologous recombination repair protein RAD51 and methotrexate-enhanced radiosensitivity.Methods Western blot and RT-PCR assays were used to detect RAD51 expression in HOS osteosarcoma cells exposed to γ-ray irradiation alone and in combination with methotrexate.Colony formation assay was used to test the survival fraction of HOS cells exposed to γ-rays and methotrexate.Results Methotrexate inhibited both protein and RNA expressions of RAD51,and the combination of radiation and methotrexate enhanced the inhibition of RAD51 expression.Moreover,transfection of cells with RAD51 gene decreased cellular sensitivity to methotrexate and γ-rays.The sensitizer enhancerment ratios after irradiation in combination with methotrexate were 1.51 and 0.99,respectively.Methotrenate was a preferred radiosensitizer to HOS cell.Conclusions RAD51 might be involved in the methotrexate-enhanced radiosensitivity.

Objective To study the combined effect of interleukin-21 gene transfer and ionizing radiation on the growth of cervical carcinoma HeLa cells.Methods Previously constructed Ad-IL-21 gene was amplified by infecting 293A cells and the titer was measured by TCID50 method. HeLa cells were transfected with Ad-1L-21 and then irradiated with 6 Gy 137Cs γ-rays.The cells were divided into 5 groups,including blank control,Ad-LaeZ group,Ad-IL-21 group,radiation group and Ad-IL-21 combined with radiation group (combination group).The cell growth,cell cycle,apoptosis,and the expressions of IL-21 gene and protein in HeLa cells were detected.Results Ad-IL-21 was successfully amplified and the titer of Ad-11.-21 was 9 × 1010 pfu/ml.Compared with Ad-IL-21 group and radiation group,the cell growth of combination group was significantly inhibited at 96 h after transfection ( F =85.26,72.98,P ＜ 0.05 ).The cells in combination group were arrested in G1 phase and decreased at S phase( F =36.69,34.83,P ＜ 0.05),while the cellular apoptosis increased markedly ( F =28.23,25.57,P ＜ O.05 ). The gene expression of 1L-21 in the combination group was 1.54- and 2.43-fold of Ad-IL-21 group and blank control group,respectively (F=22.31,36.65, P ＜ 0.05 ), while the protein expression of IL-21 in the combination group was 1.62-fold and 2.31-fold of Ad-IL-21 group and blank control group,respectively ( F =27.36,35.86,P ＜ 0.05 ).Conclusions Ad-IL-21 gene transfection combined with radiation has synergic effect on the inhibition of cervical carcinoma cell growth.

Objective To study the influence of irradiation on the osteoblast function by the gene expression changes of RANKL and OPG.Methods Bone marrow stromal cells were induced to develop into early and mature osteoblasts in vitro.The characterization of osteoblasts was indentified by ALP staining.The RANKL and OPG mRNA levels in early and mature osteoblasts, which exposed to 0 -4 Gy radiation were determined by RT-PCR.Results Bone marrow stromal cells had been induced to early and mature osteoblasts by osteoblast differentiation medium in vitro.In early stage of osteoblast, RANKL mRNA expression levels treated with 1Gy irradiation was 2.83-fold higher than those other irradiation dosage groups.The RANKL mRNA expression levels of each group in early stage of osteoblasts were significantly higher than those in the mature counterpart ( t = 8.34 - 103.57, P ＜ 0.05 ).The ratio of RANKL/OPG mRNA was obviously greater in early osteoblast compared with the mature cells ( t = 2.84 - 20.99, P ＜0.05 ), and it was the highest in 1Gy irradiation treated early osteoblast.Conclusions Radiation exposure of the early osteoblasts promotes osteoclasts function and results in the bone loss.

Objective To screen and isolate the radioresistance related genes of IRM-2 mice.Methods cDNA library of IRM-2 mice was constructed by SMART technique.Total RNA was isolated from spleens of IRM-2 male mice.The first-strand cDNA was synthesized by using PowerScript reverse transeriptase,and double-strand cDNA was synthesized and amplified by long PCR.The PCR products were purified,digested with restriction enzyme Sfi I.The ds-cDNA fragment lessthan 500 bp was fractionated and ligated to the Sfi I-digested pDNR-LIB vector.The ligation mixture was transformed into E.coil DH5α by electroporution transformation to generate the unamplified cDNA library.The quality of cDNA library was identified by PCR technique.130 clones from cDNA library were sequenced and compared with GenBank database.Results The cDNA library contained 2.25 x 106 independent clones with an average insert size of 1.2 kb.The ratio of recombination and full-length was 95% and 55%,respectively.21 pieces of EST sequences from cDNA library were not the same as the known mice genes and registered into GenBank EST database,with registered number DW474856-DW474876.Conclusions cDNA library of IRM-2 mice has been constructed successfully.21 pieces of EST implies that radioresistance correlative genes may be in IRM-2 mice,which will lay a foundation for isolating and identifying radioresistance related genes in further study.

Objective To investigate the inhibition effect of silencing Ku80 gene combined with irradiation on growth of esophageal cancer xenografs. Methods shRNA-Ku80 vector was constructed.The expression of Ku80 protein was inhibited by shRNA-Ku80 vector by using Western blotting. 20 BALB/c nude mice were randomly divided into 4 groups, including control group, radiation group, shRNA-Ku80 group and combined group. The growth of esophageal cancer xenografs was observed. The expression of Ku80 was examined in esophageal cancer xenografs by IHC. Results Effective target sequence was selected. The growth of esophageal cancer xenografs was inhibited by shRNA-H2 and radiation, especially in combined group. The inhibition rate of growth in three groups above was 32.0% , 39. 9% and 68. 9% ,respectively. The expression of Ku80 was reduced to 58% by shRNA-H2 in esophageal cancer xenografs ( t = 3.77, P ＜ 0. 05 ). Conclusions Combination of silencing Ku80 and radiation could enhance radiotherapeut effect of esophageal cancer xenografs.