1.Development of Ebp1 in tumor proliferation and invasion
Yuan LIU ; Fei ZHANG ; Ruifang NIU
Chinese Journal of Clinical Oncology 2014;(23):1536-1539
This work summarizes the research development and molecular mechanism of Ebp1, a member of the proliferation-associated 2G4 family, in tumor proliferation and invasion. This research serves as a basis and support for further research on the mechanism of tumor proliferation and invasion. The low expression of Ebp1 in various cancers promotes tumor proliferation and invasion. Ebp1 inhibits E2F1, cyclin D1, and cyclin E transcription by interacting with Rb, human histone deacetylase 2, and the transcriptional repressor Sin3A. This inhibition triggers cell cycle arrest and suppresses cell proliferation. Ebp1 also influences cancer invasion and migration. However, the underlying mechanisms remain unknown and require further exploration.
2.Analysis of VMAT dosimetric verifications with different techniques
Zhenyang NIU ; Zhenle FEI ; Zongjin DUAN ; Zhijie LI ; Lei WANG
Chinese Journal of Radiation Oncology 2017;26(8):929-933
Objective To investigate the gamma (γ) passing rates for volumetric-modulated arc therapy (VMAT) dosimetric verification with different techniques.Methods A total of 12 VMAT plans for the treatment of different anatomical sites in cancer patients were chosen.The Octavius 4D system was used to measure the dose distributions in two different settings:the gantry was rotating (three-dimensional (3D) and 2D γ-analysis) and the gantry was fixed at 0°(2D γ-analysis).The γ passing rates were analyzed with 3%/3 mm and 2%/2 mm criteria, using the paired t test or Wilcoxon signed-rank test.The 2D γ passing rates for different irradiation methods were calculated.Results For the 3D and 2D dose distributions obtained at a rotating gantry angle as well as the 2D dose distribution obtained at zero gantry angle, the average γ passing rates were 96.03%, 96.98%, and 98.90% for 3%/3 mm (P=0.227, P=0.000, P=0.003);82.08%, 84.04%, and 90.90% for 2%/2 mm (P=0.379, P=0.000, P=0.000).For the 2D dose distributions obtained with different irradiation methods, the average γ passing rate was 98.99% for 3%/3 mm and 93.68% for 2%/2 mm.Conclusions The VMAT dosimetric verification based on a 3D volumetric dosimeter at a rotating gantry position can be clinically useful for delivery quality assurance (QA), and can achieve the most reliable dose calculation for VMAT, which has more referential values.
3.Application of detector array in treatment planning system modeling adjustment
Zhenyang NIU ; Zhenle FEI ; Zongjin DUAN ; Zhijie LI ; Lei WANG
Chinese Journal of Radiation Oncology 2017;26(7):806-809
Objective To investigate the feasibility of detector array in Monaco modeling for MLC parameters adjustment.Methods One parameter was fixed, and then the other parameter was changed.The γ pass rates of the test beams, namely 3ABUT, 7SegA, and FOUR L, were assessed to determine the values of leaf transmission and leaf offset.A total of 12 tumor cases from different anatomical sites were randomly selected.Two-dimensional dose verification (rack angle zero) of Step& Shot and dMLC plans as well as three-dimensional dose validation of VMAT plan were performed using Octavius 4D system.The γ pass rates were analyzed at a standard of 3%/3 mm.Meanwhile, the point dose verification for these three plans was analyzed to obtain the dose deviations.Results The values of leaf transmission and leaf offset were 0.0105 and-0.08 mm, respectively.The average γ pass rates (%) of Step& Shot, dMLC, and VMAT plans were 88.59±2.94, 87.81±3.28, and 87.45±2.24 before adjustment and 98.45±1.23, 98.9±1.01, and 96.03±1.66 after adjustment.In addition, the average dose deviations (%) according to the point dose verification were 0.85±0.75, 0.95±0.39, and 0.98±0.40 before adjustment and 0.97±0.57, 1.08±0.76, and 0.86±0.45 after adjustment.Conclusions Octavius detector 729 ionization chamber array is a feasible and reliable device in Monaco modeling for MLC parameters adjustment.
4.The research about bcl-2/bax/fas/fasL mRNA of splenic lymphocytes in HIBD rat model
Rui YAN ; Guilan CHU ; Rongxiu ZHENG ; Ruifang NIU ; Fei ZHANG
Chinese Journal of Microbiology and Immunology 2010;30(10):937-941
Objective To obtain the change of bcl-2/bax/fas/fasL in splenic lymphoctyes with different lasting time of hypoxicischemic brain damage (HIBD). Methods The newborn rat were divided into 6 groups by the time of being HIBD model randomly, includes 1/6/12/24/48/72 hour(s) (8 for every group),and control groups were established at the same time point. The following four apoptosis related genes bcl-2/bax/fas/fasL were tested by real time PCR. Results ( 1 ) bcl-2: the mRNA expressions of HIBD groups were lower than control groups at the same time ( P<0.01 ). Eliminated the control effects, the mRNA expressions of HIBD groups were differernt by the modeling time(P <0.01 ). (2)bax: the mRNA expressions of HIBD groups were higher than control groups at the same time( P <0.01 ), and in control group the expression of 6 h was much higher than any other groups (P<0.01 ). Eliminated the control effects, the mRNA expressions of H IBD groups were different by the modeling time( P<0.01 ). (3)bcl-2/bax: the ratios of HIBD groups were lower than control groups at the same time( P <0.05 ), the ratios in control groups were higher than 1 ( except for 1 h); while in HIBI) groups the ratios were lower than 1; Eliminated the control effects, the ratios were different in all the groups. (4)fas: the mRNA expressions of HIBD groups were higher than control groups at the same time ( P <0.01 ), and both were maximum at 6 h. (5)fasL: the mRNA expressions of HIBD groups were higher than control groups in 1 h and 6 h ( P<0.01 ), while lower than control group at other time points( P<0.01 ),the expression of 24 h was the maximum of control groups and 12 h was the maximum of HIBD groups. (6)fas/fasL: the ratios of HIBD groups were higher than control groups( P <0.01 ) (except for 6 h), and the ratios in control groups were lower than 1 ( P<0.01 ) ( except for 6 h), and not concentrated, while in HIBD groups were higher than 1 ( except for 24 h), between 0.69 to 5.65. Conclusion Pro-apoptosis genes ( include bax/fas/fasL) were promoted by HIBD, while anti-apoptosis gene(bcl-2) was inhibited. The maximum of pro-apoptosis genes became early in HIBD. Both the pro- and anti-apoptosis genes got their maximum at 6 h and 12 h of HIBD. The apoptosis suppression was the main effects in control groups from the ratio of bcl-2/bax, which was lower than 1. The apoptosis promotion was the main effects in HIBD groups from the ratio of bcl-2/bax, which was higher than 1, especially at 12 h. Thefas/fasL effect which is the major way of lymphocytes apoptosis was strengthened in HIBD.
5.Strategies of the phenomenon of college teachers' multimedia dependency
Juan WANG ; Fei JIAO ; Yuan YU ; Xinhua NIU ; Min YU
Chinese Journal of Medical Education Research 2011;10(7):819-821
Currently, multimedia teaching plays a more and more important role in colleges.However, the negative effects of multimedia teaching have gradually revealed because of the neglection of its limitations. In this article, strategies were proposed from three different aspects against disadvantages of multimedia teaching in colleges in order to improve its role more effectively.
6.Transmural mechanics at the infarcted myocardium of a dog model of acute myocardial infarction
Junli WANG ; Lixue YIN ; Liping FEI ; Qingying NIU ; Wenhua LI
Chinese Journal of Tissue Engineering Research 2014;(27):4293-4298
BACKGROUND:Acute myocardial infarction with acute onset is dangerous, but the aided diagnosis for hyperacute disease mainly depends on electrocardiogram. The advantages of tissue Doppler strain imaging were utilized to help early diagnosis of acute myocardial infarction.
OBJECTIVE:To observe left ventricular transmural peak radial strain and strain time-to-peak of subendocardiac muscle, midmyocardium and subepicardiac muscle using tissue Doppler strain imaging in dogs before and after acute myocardial infarction, and to assess its mechanical characteristics.
METHODS:A total of 16 Beagle dog models of acute myocardial ischemia were established by ligating left anterior descending coronary artery. The two-dimensional apical short-axis views of the left ventricle in five complete cardiac cycles were acquired and stored in TDI-Q workstation before and after acute myocardial ischemia. Transmural peak radial strain and strain time-to-peak of segment, subendocardiac muscle, midmyocardium and subepicardiac muscle at infarct region and baseline were observed.
RESULTS AND CONCLUSION:Peak radial strains at infarct and subendocardiac muscle, midmyocardium and subepicardiac muscle were decreased compared with the baseline (P<0.05). Peak strain gradient disappeared in each layer of infarct myocardium. Strain time-to-peak of the whole segment and infarct myocardium at different layers was significantly postponed (P<0.05). There was a positive correlation of peak radial strain between subendocardium and segment as wel as between medium and segment at baseline (r=0.617, P<0.01;r=0.556, P<0.01). This relationship disappeared at infarct region (r=0.338, P>0.05;r=0.218, P>0.05). Results indicated that after acute myocardial infarction, peak strain gradient disappeared at different layers at infarct region. Acute myocardial ischemia induces peak radial strain decrease at subendocardium, medium, subepicardium and strain time-to-peak at infarct region was significantly postponed, which reflected abnormal cardiac structure and dysfunction, resulted in uncoordinated cardiac motion and asynchronous heart movement. This may be an important mechanical mechanism triggering heart failure.
7.Simulation of respiratory motion effect on dose distributions in three-dimensional radiotherapy
Zhenle FEI ; Zhenyang NIU ; Zhijie LI ; Lei WANG
Chinese Journal of Radiation Oncology 2012;(6):554-556
Objective To evaluate the effects of respiratory on dose distributions in threedimensional conformal radiotherapy (3 DCRT) and intensity-modulated radiotherapy (IMRT).Methods The dose distributions were measured with a PTW 2D-ARRAY seven29 placed on a home-made moving platform to simulate the respirator.Dosimetric comparisions for 3DCRT and IMRT plans were performed by means of Gamma analysis with 3% and 3 mm,respectively.Dose distribution measured for static treatment plans.Results The respiratory could reduce the target does and conformal index.The r pass rate (3%3 mm in 3 DCRT was greater than it in IMRT ((53.58 ± 0.74) %,(30.71 ± 1.00) %,t =57.91,P < 0.01).The failed points were mainly near the field edge,but located in the whole target volumes for IMRT plans.Conclusions It is undesirable to use IMRT techniques for tumors with large motion amplitude.3DCRT can give a reliable dose distribution by reasonably selecting the PTV margin.
8.Research progress of hypoxia-inducible factor 1 inhibitors against tumors.
Fei NIU ; Yan LI ; Fangfang LAI ; Xiaoguang CHEN
Acta Pharmaceutica Sinica 2014;49(6):832-6
Hypoxia occurs in chronic and acute vascular diseases and tumor formation. The ability of tumor cells to maintain a balance between an adaptation to hypoxia and cell death is regulated by a family of transcription factors called hypoxia-inducible factor 1 (HIF-1). Tumor hypoxia mediated by HIF-1 would facilitate the likelihood of resistance to chemotherapy and radiotherapy, proliferation, metastasis and the invasive potential; all of which culminate in a decrease in patient survival. And HIF-1 alpha subunit decides the activity of HIF-1, which is regulated by oxygen. So understanding the role of HIF in signal pathway, drug resistance mechanism and its feature is crucial for developing novel anticancer therapies. In recent years, more attentions have focused on HIF-1 alpha inhibitors. It is expected that development of more potent and selective HIF inhibitors will provide an effective treatment of cancer and other HIF-related diseases. So we will focus on the biological characteristics and mechanism of HIF-1 to review currently studied HIF-1 inhibitors.
9.Development of a novel screening assay for inhibitors targeting HIF-1alpha and P300 interaction.
Fangfang LAI ; Fei NIU ; Hanze YANG ; Wanqi ZHOU ; Xiaoguang CHEN
Acta Pharmaceutica Sinica 2014;49(6):849-53
Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.