Three-dimensional cell culture is widely recognized as a model in vitro that can better simu-late the interaction between tumor cells in vivo and cell microenvironment. Compared with the traditional two-dimensional cell culture,it has obvious advantages in the study of the observation of tumor cells biological be-havior,tumor resistance,radiation insensitivity,gene expression in vivo and in other aspects of the study. It can provide a valuable model in vitro for experimental study on the basis of tumor.

The curriculum of oncology radiotherapy covers basic radiology,clinical oncology and other aspects.With the development of new radiation therapy technology and the extensive application of computer technology in the field of radiotherapy,the traditional lecture-based teaching model has not adapted to the rapid development of the needs of oncology radiotherapy any more.Teachers in the first affiliated hospital of Soochow university integrated computer multimedia with problem-based learning in the teaching of oncology radiotherapy.With those innovations,the quality of teaching as well as the creative and self-learning abilities of students have been enhanced.

Objective To analyze the curative effects,late phase reactions and their prognostic factors of nasopharyngeal carcinoma (NPC) treated with radiotherapy.Methods Retrospective analysis was made for 246 cases of NPC which were confirmed by pathological diagnosis and with complete follow-up data in the first affiliated hospital of Soochow university.Kaplan-Meier method was used for analysis of survival rate and the log rank method was used to compare the survival between groups.Cox regression was used for analysing the prognostic factors.Logistic regression was used for analysing the factors which affect the late phase reactions.Results The follow-up rate was 94.6％.The 1-year,3-year,5-year overall survival (OS) were 97.97％,81.82％,67.85％.The 1-year,3-year,5-year progression-free survival (PFS) were 83.33％,70.00％,39.29％ respectively.Age (x2=6.604,P=0.010),T stage (x2 =3.670,P=0.050),N stage (x2=19.658,P =0.001) and the clinical stage (x2 =4.626,P =0.031) were the prognostic factors for the OS.Cox multi-variate analysis showed that the independent prognostic factors for the OS were clinical stage and age.Logistic regression analysis showed that the independent prognostic factors for the late phase reactions were age and rehabilitation time.Conclusion The main factors for the long term survival of NPC patients after radiotherapy are early TNM stage and young age.Patients with younger age and longer rehabilitation time have lower incidence of late phase reactions.

Objective To evaluate the effect of Fat Mass and Obesity Associated (FTO) gene on radiosensitivity of human glioma cell A172 and investigate its potential mechanism by changing the expression of FTO gene.Methods Cells were divided into five groups according to their FTO protein expression level.The normal expression group was recorded as A172 Group,the low-expression and its negative control group was A172/siRNA and A172/NC Group,and the over-expression and its negative control group was A172/FTO and A172/PC group.FTO protein expressions were assayed by Western blot in A172 Group after irradiation.Clonogenic assay was executed to evaluate the relationship between FTO gene and radiosensitivity.Immunofluorescence and Western blot assay were applied to detect the proteins of DNA damage and repair.Results FTO protein expression level in A172 Group was significantly related to the irradiation dose and the time post-irradiation.The radiosensitization ratio (SERD0) of A172/siRNA and A172/FTO group were 1.829 and 0.812 respectively.Not only the number of γ-H2AX foci increased (t =-21.884,P ＜ 0.05) in A172/siRNA 1 h post-irradiation but the decreases of p-p95/NBS1 and Ku80 proteins were also detected (t =24.731,23.293,P ＜ 0.05) together with the increase of Rad50 protein (t =3.140,P ＜ 0.05).But the expressions of these proteins in A172/FTO group were opposite to the above phenomenon (t =0.642,-8.364,26.829,P ＜ 0.05).Conclusions FTO gene is a radiation-resistant gene,which may because the regulation of FTO gene could alter the primary injury and DNA damage repair in the irradiated tumor cells.

Objective To evaluate the radiosensitization effect of low-temperature plasma on HepG2, A549, and HeLa cells.Methods Cells were divided into three groups, radiation group (R) , plasma treatment group(P), and plasma plus radiation group (P + R).After radiation, cell survival was detected by a cloning assay.Cell cycle distribution, apoptosis and ROS content were tested by flow cytometry.Western blot was used to measure the expressions of Caspase-3 and Bcl-2.Results Lowtemperature plasma showed radiosensitization effects on three different human malignant cell lines with a sensitivity enhancement ratio(SERD0) of 1.28,1.32 and 1.29.respectively.In these three different human malignant cell lines, compared with radiation alone group (R) , the G2/M arrest, apoptosis rate and ROS level in the group P + R were enhanced (the prolongation of G2/M arrest: t =9.52, 8.24, 9.53, P ＜ 0.05;the apoptosis rate: t =10.67, 38.56, 6.74, P ＜0.05;ROS content: t =9.41, 15.42, 13.53, P ＜0.05).In HepG2 cells and A549 cells, compared with group P, the prolongation of G2/M arrest, the apoptosis rate and ROS content of group P + R were enhanced (the prolongation of G2/M arrest: t =8.75, 20.37, P＜0.05;the apoptosis rate: t =8.43, 9.99, P ＜0.05;ROS content: t =4.82, 5.27, P ＜ 0.05).The expression level of Bcl-2 protein was downregulated in group P + R;by contrast, the expression level of Caspase-3 protein in group P + R was upregulated.Conclusions Low-temperature plasma can increase the radiosensitization of HepG2, A549 and HeLa cells with the enhancement of G2/M phase arrest, apoptosis induction and ROS generation.

Objective To compare the radiosensitivity effect of celecoxib on oln93 and u373 cells,and to explore the related mechanism.Methods Both oln93 cells and u373 cells were respectively divided into control group,drug group,radiation group and combined group when treated with celecoxib and irradiation.Cell survival ratio was evaluated by MTT assay and clogenic assay.Flow cytometry and Western blot assay were used to measure cell cycle and protein expression.Results Celecoxib had a similar effect on oln93 and u373 cells in enhancing the radiosensitivity (t =2.215-30.996,P ＜ 0.05 ; t =0.383-11.732,P＜0.05)and blocking cellcycle in G0/G1(t=-6.1-5.141,P＜0.05).Compared with the radiation group,the combined group showed S phase arrest(t =-18.174,P ＜ 0.05),and increase of Cyclin A protein (t =-8.087,P ＜ 0.05) in oln93 cells,and G2/M arrest and decrease of Cyclin B1 and DNA-PKcs and MRE11 protein (t =-8.838-10.45,P ＜ 0.05) in u373 cells.Conclusions Celecoxib illustrates a more sensitive radiosensitivity to u373 cells by regulating its cell cycle and DNA damage repair.

Objective To investigate the radiosensitizing effect of knock-down the expression of miR-21 on human SHG-44 glioma cells and explore the possible mechanism. Methods Antisense oligonuleotidas of miR-21, mediated by LipofectamineTM 2000, were transfected to SHG-44 cells. Three groups were: blank control group ( mock group), negative control and antisense transfected group ( AS-miR-21 gorup). Cells of each group were irradiated with 6 MeV X-rays at the doses of 0,1,2,4,6 and 8 Gy.Dose-suvivial curve was established by colony-forming assay. The influence of AS-miR-21 on cell cycle and cell apoptosis was analyzed by flow cytometry assay after 6 Gy irradiation. Results The value of D0 and Dq of AS-miR-21 group declined obviously compared with the mock group and negative control group. Flow cytometric analysis showed that cell cycle distribution changed( G0/G1 phase arrest, S phase decreased)after transfected with AS-miR-21 (t = 8.18, -4.52,P ＜ 0.05 ). The sensitization enhancement ratios of D0 and Dq were 1.32 and 2.10 respectively. Apoptosis assay showed the early apoptosis rate was signiflcantely increased in AS-miR-21 、irradition alone and combined group than mock control group( t = 20.14,11.11,50.07, P ＜ 0.05). Conclusions AS-miR-21 can enhance the radiosensitivity of human glioma cells SHG-44 by promoting cell apoptosis and faciliating cell cycle redistribution.

Objective To investigate the effects of radiosensitivity enhancement and inhibition of migration ability of human lung adenocarcinoma cells by celecoxib,a selective cyclooxygenase (COX)-2 inhibitor.Methods Human lung adenocarcinoma cells of the line A549 were cultured and then inoculated into six-well plates and randomly divided into 4 groups:control group,celecoxib group administered with celecoxib at the subtoxic doses 30 and 50 μmol/L,irradiated group exposed to 0,1,2,4,6,or 8 Gy by linear accelerator,and combined treatment (celecoxib + irradiation) group.The radiosensitizing effect of celecoxib was assessed by clonogenic cell survival test.The migration ability of the A549 cells was measured by scratch-wound test and the content of metalloproteinase-2 (MMP-2) in culture supernatant was detected with ELISA.Results The sensitization enhancement ratio of the celexib group was increased dosedependently.The values of D0 ,Dq,SF2 and D0.01 of the celecoxib + irradiation group were all significantly lower than those of the irradiated group.Scratch-wound test showed that the no-scratch area of the celecoxib + irradiation group and celecoxib group were all significantly wider than those of the mere irradiation and control groups and there was a dose-dependent manner,and the no-scratch area of the celecoxib + irradiation group was wlider than that of the celecoxib group.ELISA showed that the MMP-2 levels in the supernatant of the celecoxib group and celecoxib + irradiation group were respectively significantly lower than those of the control group and mere irradiated group (t = 3.78,5.79、3.15,P ＜ 0.05),however,there was not significant difference between the mere irradiation and control groups (t = 2.73,2.38,P ＞ 0.05).Conclusions Celecoxib enhances concentration-dependently the radiosensitivity of human lung carcinoma cell and inhibits the secretion of MMP-2 of the carcinoma cells,thus inhibiting their migration ability.

Objective To detect DNA damage of peripheral blood lymphocytes in patients and family members of autosomal dominant polycystic kidney disease (ADPKD),and to study the effect of irradiation on genomic stability of lymphocytes. Methods Before and after 0.5 Gy radiation dose,single-cell gel electrophoresis (SCGE) was employed to analyze DNA damage of lymphocytes in 10 ADPKD patients (group A),3 members without clinical symptoms of a ADPKD family (group B) and 20 healthy control people (group C).The damage was estimated based on the content of DNA in tail (TDNA％) with comet analysis software (CASP). Results Both before and after irradiation,the TDNA％ (8.85％±0.14％,14.84％±0.77％) and the value-added (6.00％±0.77％) of TDNA％ of group A were significantly higher than those of group C (7.50％±0.37％,12.46％±0.26％,4.96％±0.44％) respectively.There were no significant differences between group B and group C or group A and group B.While 1 person in group B had higher TDNA％ as compared to group C both before and after irradiation. Conclusions The lymphocytes of ADPKD patients are more sensitive to ionizing radiation as compared to healthy people.The genomic instability in ADPKD patients or member of ADPKD family may trigger cystic formation in multi-organs when exposing to environmental agents. SCGE may provide a new approach to elucidate the pathogenesis and prognosis of ADPKD.

Objective To observe the differences of the radio-biological characteristics between the human malignant glioma cell line SHG-44 and its progeny cells SHG-4410 Gy and to probe the underlying mechanism.Methods The SHG-4410 Gy cells were the progeny of SHG cells that had been irradiated with 10 Gy X-rays and then passaged for 15 generations.The radiosensitivity of SHG-44 and SHG-4410 Gy wre measured by clonogenic assay and the multi-target single-hit model was used to fit the survival curve.The cell cycle redistribution and apoptosis were analyzed by flow cytometry assay.Quantitative Real Time-PCR (qRT-PCR) was used to determine the relative levels of cyclin B1 mRNA and miR-21.Stat3 protein levels were detected by Western blot.Results The values of D0,Dq and SF2 of SHG-4410 Gy cells were significantly higher than those of SHG-44 cells.Flow cytometric analysis showed that there was less G2/M phase arrest in SHG-4410 Gy (F =22.21,P ＜ 0.05).Radiation-induced early apoptotic population was increased from (17.60 ± 0.26) ％ to (28.00 ± 0.36) ％ for SHG-44 cells,but increased from only (4.20 ± 0.30)％ to (5.17 ± 0.65)％ for SHG-4410 Gy.miR-21 in SHG-4410 Gy cells were increased by 1.44 fold of SHG-44 cells,which was associated with the increase of Stat3 protein expression.Conclusions Radioresistance is observed in the progeny of human malignant glioma cell line SHG-44 which had been irradiated with 10 Gy X-rays.The underlying mechanisms may be relative to the upregulation of cyclin B1 that acts as a key downstream gene in the signaling pathway of G2/M phase transition.In addition,the upregulation of miR-21 may be involved in the apoptosis of SHG-4410 Gy cells.