Objective To summarize the current advancement of preoperative radiotherapy for rectal cancer. Methods Relevant literatures about current advancement of preoperative radiotherapy for rectal cancer published domesticly and abroad recently were collected and reviewed. Results The lower local recurrence rate and longer disease-free survival time were observed in preoperative radiotherapy， compared with postoperative radiotherapy for rectal cancer. The recurrence rate was higher in short-course radiotherapy， compared with conventionally radiotherapy for stageⅢrectal cancer， but there was no significant difference for stageⅡrectal cancer. The biology molecular such as p53， CEA， Cox-2， EGFR， and VEGF had shown to be radiosensitive. Conclusions The proposal of preoperative radiotherapy for rectal cancer， could be prone to conventionally radiotherapy. There are more screening targets for preoperative radiotherapy in extensive exploration of diverse radiosensitivity. Biology molecular， developed gene expression profiling， and gene chips for rectal cancer may contribute to the individualization treatment.
Objective To investigate the radiation-sensitizing effects of Ku80 silencing by siRNA interference for A549 lung cancer cells. Methods The sequences of Ku80 siRNA and negative siRNA were chemically synthesized and transfected into A549 lung cancer cells by lipofectamine. RT-PCR and Western bolt analysis were used to determine Ku80 gene expression. The transfected cells in culture dishes were irradiated with X ray at doses of 2 Gy, 4 Gy, 6 Gy, 8 Gy, 10 Gy, respectively. Once all treatments were completed, the cells were processed with the colony formation assay. Results RT-PCR detection showed that Ku80 mRNA levels in A549 lung cancer cells were reduced after transfected with Ku80 siRNA at 24 h, 48 h and 72 h time points. Western blot analysis showed that Ku80 protein content decreased at 48 h and 72 h time points compared with the control group ( P lt; 0. 05 ) . Cloning formation assay indicated that radiosensitivity of A549 lung cancer cells was enhanced after transfected with Ku80 siRNA. Conclusion Ku80 siRNA can effectively inhibit Ku80 gene expression of A549 lung cancer cells, and therefore enhance its radiosensitivity.
We have studied the radiosenstivity of retinoblastoma cell [inc: HXO Rb~4,and found that the ceil growth reduced markedly after being treated by 3GyT-ray. From both clone for mation method and MTT assay,we identify that HXO-Rb44 cell is radiosensitive to T-ray.Oxygen can increase the radiosensitivity of HXO-Rb44 cell, but decrease the repair of sublethal damage.Oxygen enchaneement ratio(OER)is 2.77~3.01. （Chin J Ocul Fundus Dis,1994,10:217-219）
Objective To investigate the effects of X-ray dose on the expressions of microRNA-221 （miR-221） and phosphatase and a tensin homolog deleted from chromosome10 （PTEN） in human colorectal carcinoma （CRC） cells. Methods Human CRC-derived cell line， Caco2， was cultured conventionally. The cells were divided into five groups and exposed to different doses of X-ray （0， 2， 4， 6， and 8 Gy） respectively. The total RNA and protein of the Caco2 cells were extracted after irradiation， and the miR-221 and PTEN mRNA expressions were detected by real-time RT-PCR.Moreover， the protein alteration of PTEN in Caco2 cells was detected by Western-blot analysis. Results The radiation dose of X-ray significantly affected the expressions of miR-221 and PTEN protein in human Caco2 cells in a dose-depen-dent manner. Moreover， the miR-221 expression level was up-regulated gradually with the increase of irradiation dose， on the contrary， the PTEN protein expression level was down-regulated gradually （P＜0.01）. Conclusion The radiation dose can affect the miR-221 and PTEN protein expression pattern in CRC cells.
Objective To investigate the effects of matrine on proliferation, apoptosis and radiotherapy sensitivity of uveal melanoma cells. MethodsAn animal experiment study. In vitro experiment: MuM2B cells of human choroidal melanoma were randomly divided into control group and matrine 0.25, 0.50, 1.00, 2.00 g/L groups. The cell morphology was observed by transmission electron microscope. Cell proliferation was detected by thiazole blue colorimetry. The mRNA and relative expression levels of CyclinD D (CyclinD), B lymphoblastoma-2 (Bcl-2) and Bcl2-associated X protein (Bax) were detected by real-time polymerase chain reaction and Western blot. In vivo experiment: BALB/C mice were injected with MuM2B cell suspension subcutaneously on the back of forelimb to prepare transplanted tumor model. After successful modeling, they were randomly divided into blank group and matrine treatment group with different concentrations. Mice in blank group were injected with phosphate buffer subcutaneously. Mice in different matrine treatment groups were injected with 15, 25, 50, 100 mg/kg matrine subcutaneously, respectively, for 7 consecutive days. The tumor was weighed and its volume was measured after the last administration. Single factor analysis of variance was used to compare different groups. The t test was used for pairwise comparison between groups. ResultsIn the control group, the cell structure was normal, the distribution was uniform, and no or rare nuclear pyknosis was seen. With the increase of matrine dosage, the nuclear pyretosis increased gradually and cell morphology changed obviously. Compared with the control group, the cell survival rate in 0.50, 1.00 and 2.00 g/L groups gradually decreased with matrine concentration increasing and treatment time prolongating, the relative expression levels of CyclinD and Bcl-2 mRNA and protein gradually decreased, and the relative expression levels of Bax mRNA and protein gradually increased. Under the same radiation dose X-ray irradiation, the cell survival rate of 0.50, 1.00 and 2.00 g/L groups gradually decreased, and the differences were statistically significant (P＜0.05). Compared with blank group, the tumor weight and volume of mice in different doses of matrine group were significantly decreased, and the differences were statistically significant (P＜0.05). ConclusionMatrine can down-regulate the expression of CyclinD and Bcl-2, up-regulate the expression of Bax, promote the apoptosis of MuM2B human melanoma cells, inhibit cell proliferation, and enhance cell radiosensitivity.