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Objective To evaluate if 18F-FLT PET imaging could be used as a new clinical method to predict tumor radiosensitivity.Methods MDA-MB-231 and LN229 cells were irradiated with doses of 0,8 and 16 Gy of 6 MV photon energy,then soft agar assay and cellular uptake of 18F-FLT were performed on the 2 cell lines.The t test and one-way analysis of variance were used for the two groups and data before and after irradiation.The MDA-MB-231 and LN229 tumor xenografts were prepared by injecting the tumor cells into the right limbs of female BALB/c nu/nu mice.Once tumors reached a diameter of 10 mm,the two types of mice were divided randomly into 3 groups (20 mice per group) according to the irradiation doses (0,8 and 16 Gy).After irradiation,18F-FLT PET imaging and immunohistochemical staining were conducted.Then correlations between 18F-FLT SUVtumor/SUVmuscle ratio (T/M ratio) and TK1 labeling index percentages (LITK1) were tested using linear correlation analysis.Results The survival fraction of MDA-MB-231 and LN229 cells after irradiated with 8 Gy were (59.73 ± 4.3) ％ and (93.41 ± 3.75) ％,respectively (t =-13.20,P ＜ 0.001).When the dose increased to 16 Gy,the survival fraction decreased to (43.57 ±4.06) ％ and (81.77 ± 4.42) ％,respectively(t =-14.24,P ＜ 0.001).In MDA-MB-231 cells,the cellular uptake of 18F-FLT after irradiation with 8 Gy declined rapidly to (18.32 ± 1.38) kBq/105 cells ((128.22 ± 8.24) kBq/105 cells with the dose of 0 Gy,F =266.41,P ＜ 0.01),and maintained this low level till 72 h.For the LN229 cells,the cellular uptake decreased to (9.87 ± 1.30) kBq/105 cells after 8 Gy irradiation ((134.88 ± 6.59) kBq/105 cells with the dose of 0 Gy,F =346.06,P ＜ 0.01),then increased gradually to (127.17 ± 9.08) kBq/105 cells at 72 h (F =346.06,P ＞ 0.05).The dynamic changes of 18F-FLT cellular uptake in the two cells had the same pattern after being treated with 16 Gy irradiation.In the 18F-FLT PET image of MDA-MB-231 tumor mice after 8 Gy radiotherapy,the T/M ratio decreased to 0.78 ± 0.39 at the first day,but it was 2.84 ± 0.29 before radiotherapy (F =39.78,P ＜0.01).Then the ratio increased slowly,and it was still lower than the baseline at 7 d after radiation (F =39.78,P ＜0.01).The same pattern could be seen in the group of 16 Gy irradiation.In LN229 tumor mice treatment with 8 Gy irradiation,the T/M ratio increased to 2.41 ±0.47 at the first day,and it was 1.58 ±0.29 before radiotherapy (F =34.01,P ＜ 0.05).The ratio decreased steadily to 0.66 ± 0.32 (F =34.01,P＜0.05) at 7 d after radiotherapy.However,in the treatment group with 16 Gy,the T/M ratio decreased gradually and reached 0.44 ± 0.22 at 7 d (F =41.85,P ＜ 0.01).A correlation was found between 18F-FLT T/M ratio and LITK1 (8 Gy:r=0.67,0.73; 16 Gy:r=0.73,0.69; all P＜0.01) in both tumor models.Conclusion 18F-FLT PET imaging may be used as a new assay to predict tumor radiosensitivity,but further investigation is needed before clinical application.
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Objective To evaluate whether 18F-fluorothymidine(FLT) can be used to monitor early response to irradiation in colorectal cancer (CRC).Methods SW480 cells were cultured and irradiated with 0, 10, and 20 Gy.Twenty-four hours later, morphological changes, apoptosis, necrosis, proliferation,and cell cycle phases were observed.Uptake of 18F-FLT was measured in these tumors in vitro from 24 h to 72 h after irradiation.The one-way analysis of variance was used to analyze the data.Results Apoptotic and necrotic cells were detected 24 h after radiotherapy.SW480 cells proliferation was significantly delayed after irradiation in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide (MTI) assay.Cell cycle analysis showed that SW480 cells had a decreased fraction of cells in S phase( from 33.23% to 9.24%,then to 5.43% ) and an arrested fraction in G0-G1.After SW480 cells were cultured for60 min, the uptake of 18F-FLT was (5.21 ± 1.60) %; and 24 h after irradiation of 10 Gy, the uptake decreased significantly to (4.27±0.48)% (F=8.253, P=0.009).And 72 h after irradiation, the uptake further decreased significantly to (3.39 ± 0.59) % ( F = 36.715, P＜0.001 ).In tumor tissue, the uptake of 18F-FLT reduced significantly 72 h after radiotherapy (10 Gy:F = 12.388, P = 0.007; 20 Gy:F = 16.744, P = 0.004) and the attenuation degree increased with the radiation dose.Conclusion The uptake of 18F-FLT in SW480 cells or in CRC could reflect the changes of SW480 cells in proliferation, cell cycle re-distribution, cell apoptosis and necrosis.The results suggest that 18F-FLT may be used for monitoring early response to irradiation of CRC.
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Objective To investigate the inhibitiory effect of tacrolimus(FK506) and adriamycin(ADM) on hepatocellular carcinoma.Methods HepG-2 cells were cultured,and divided into 4 groups,namely(control)、FK506、ADM、FK506+ADM groups,the cells were trated by the drugs for 24 to 48 hours(respectively).The inhibitory rate of the cells was measured by MTT assay,and cell cycle and cell apoptotic rate were detected by flow cytometry(FCM).Results The ability of tumor cell growth were inhibited by FK506 after 48h;the apoptosis ratio was increased when FK506 was below 100?g/L,and when it(exceeded) that value,the apoptosis ratio was decreased.FK506 and ADM significantly prolonged cell G_2 phase;combined tacrolimus and adriamycin had synergistic role effect on arresting the cell in G_2 phase,FK506 combined with adriamycin demonstrated synergistic effect on apoptosis.Conclusions FK506 could inhibit the growth of hepatocellular carcinoma,arrest the cell in G_2 phase,and increase apoptosis.FK506 combined with adriamycin demonstrated synergistic inhibitory effect on hepatocellular carcinoma.
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Objective To establish a human cervical carcinoma cell line. Methods A primary culture was initiated from malignant tissue collected by dissection of cervical biopsy specimens.Characterizing cells in culture which included morphological observation,biological and karyotypic analysis,experimental tumorigenesis and the expression of p53,bcl-2 and Ki67 genes was carried out. Results The new established cervical carcinoma cell line (CS1213) had been maintained in culture for over 170 generations.The cells which were nonadherent had a common,rounded appearance with a cell cycle time of 25-hour and a 19 colony formation rate in soft agar.Electron micrographs demonstrated abundant tonofilaments in the cytoplasm.The karyotype showed a hyperdiploid feature with a main chromosome stem number ranged from 80 to 88.The culture was not contaminated by mycoplasma and had a distinct lactic acid dehydrogenase isozyme pattern.High expression level of p53(31.9%),bcl-2(89.3%) and Ki67(33.7%) proteins was detected by flow cytometry.The xenogeneic tumors were grown in nude mice with the histological structure of the original one. Conclusions The novel CS1213 cells have the characteristics of human cervical squamous cells and could be used as an appropriate cellular model system for studying tumor invasion and metastasis.
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Objective: To observe the effect of imbalanced BCAA on metabolism of gastric cancer cell line 800-7901 in Vitro. Methods: L-Valine(L-Val) of MEM culture medium Were restricted to serial levels of 1/2, 1/4, 1/8 or 1/16 concentration of normal With increased L-Leucine(L-Leu) concentration to 1 fold, 2 folds cc 4 folds respectively. Gastric poor differentiated cancer cell line 800-7901 and fetal liver cell were cultured in these culture media. Morphologic character of two cell lines were observed everyday. Total protein mounts were recorded on the 3nd day and 5th day of incubation. Consuming volume of L-Val , L-Les and glucose of 800-7901 were detected respectively. Results :Restricted L-Val to less than 1/8 concentration retard 300-7901 cell's growth, reduced protein volume of SGC-7901. 300-7901 cell required more glucose when L-Val supply was subtracted. At same restricted level of L-Val, increasing L-Val to 4 times increased their glucose utilization. Few effect en fetal liver cell growth was found Con-elusion: Increasing L-Leu and restricting L-Val supply can inhibit growth of cancer cell. Gastric cancer uptake high mount of L-Val for both protein synthesis end energy supply through gluconeogenesis.
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Objective To investigate the anti tumor effects of cytotoxic T lymphocytes induced by tumor antigen specific dendritic cells. Methods Soluble tumor antigen was prepared by four freeze thaw cycles of gastric tumor cell line SCG7901. Anti gastric tumor vaccine was acquired by co incubation of tumor antigen and mouse bone marrow derived dendritic cells and cultured with granulocyte/macrophage colony stimulating factor and interleukin 4. Antigen specific cytotoxic T lymphocytes were induced by this tumor vaccine from the spleen and were applied to tumor bearing nude mice. Results Tumor growth was significantly inhibited and the apoptosis of tumor cells was promoted extensively. Conclusions Antigen specific dendritic cell tumor vaccine may play an important role in future immunotherapy of gastric cancer.