miR-124 regulates radiosensitivity of colorectal cancer cells by targeting PRRX1 / 南方医科大学学报

<p><b>OBJECTIVE</b>To detect the expression of miR-124 in colorectal carcinoma (CRC) cells and tissue specimens and analyze its association with the radiosensitivity of the cells.</p><p><b>METHODS</b>The expression of miR-124 in CRC cell lines and tissues were detected using qRT-PCR. The effect of miR-124 in modulating cell radiosensitivity was assessed in CRC cells with miRNA-124 overexpression and miRNA-124 knockdown, and bioinformatics prediction and dual luciferase reporter system were employed to identify the direct target of miR-124.</p><p><b>RESULTS</b>s miR-124 expression was down-regulated in CRC cell lines and tissues. CRC cells over-expressing miR-124 showed an obviously enhanced radiosensitivity, whereas miR-124 knockdown resulted in a reduced radiosensitivity of the cells. Bioinformatics prediction and dual luciferase reporter system verified PRRX1 as a direct target of miR-124, which regulated the radiosensitivity of CRC cells by directly inhibiting PRRX1.</p><p><b>CONCLUSION</b>miR-124 can enhance the radiosensitivity of CRC cells by directly targeting PRRX1, which provides a target for improving the therapeutic effect of radiotherapy of CRC.</p>

Comparative analysis of the efficacies of entecavir capsules and lamivudine in chronic hepatitis B patients / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the efficacy profile of entecavir capsule (ETV) as a chronic hepatitis B therapy, as compared to lamivudine (LAM).</p><p><b>METHODS</b>In this multicenter, randomized, double-blind, parallel group evaluation of ETV, 232 subjects were administered a 96-week course of 0.5 mg/day ETV or 100 mg/day LAM. PCR measurement of hepatitis B virus (HBV) was conducted throughout the treatment course to determine achievement of complete virologic response (CVR; defined as less than 500 copies/ml of HBV DNA) or experience of virology rebound ( more than 500 copies/ml of HBV DNA after achievement of CVR).</p><p><b>RESULTS</b>After week-48 of treatment, the ETV group showed a higher CVR rate (90.3% vs. LAM: 59.4%) and lower virology rebound rate (1.9% vs. LAM: 13.9%). After week-96 of treatment, the ETV group continued to have a higher CVR rate (86.0% vs. LAM: 71.4%), and virology rebound was experienced by significantly less subjects in the ETV group (1.2% vs. LAM: 11.9%, P = 0.005).</p><p><b>CONCLUSION</b>ETV therapy can quickly and continuously suppress HBV replication in chronic hepatitis B patients, and has a lower resistance rate than LAM. Compared to LAM, ETV may be a superior long-term treatment choice for chronic hepatitis B.</p>

Lentivirus-mediated RNA interference suppresses APRIL expression and enhances chemosensitivity in colorectal cancer cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of lentivirus-mediated RNA interference (RNAi) targeting a proliferation-inducing ligand (APRIL) on the chemosensitivity to 5-FU of colorectal cancer cell line LoVo.</p><p><b>METHODS</b>The lentiviral vector siRNA-APRIL was constructed and verified by PCR and DNA sequencing. LoVo cells were transfected with siRNA-APRIL plasmid, non-targeting siRNA plasmid, or empty plasmid. Forty-eight hours after the transfection, the cells were examined for APRIL expression using Western blot. Seventy-two hours after treatment with 10 µg/ml 5-FU, flow cytometry was used to detect the cell apoptosis and cell cycle changes. The cell growth inhibition rate following 5-FU exposure was detected by MTT assay.</p><p><b>RESULTS</b>PCR analysis and DNA sequencing demonstrated that the RNAi sequence targeting APRIL gene was successfully inserted into the lentiviral vector. siRNA-APRIL transfection resulted in obviously reduced expression of APRIL in LoVo cells. After 5-FU exposure, the apoptosis rate of siRNA-APRIL-transfected cells were increased to (21.12∓3.35)%, significantly higher than that in cells transfected with the non-targeting plasmid or the empty plasmid [(13.06∓1.92)% and (12.28∓1.79)%, respectively, P<0.01]; the cell number in G0/G1 phase increased while that in G2/M phase decreased in siRNA-APRIL-transfected cells. The growth inhibition rate in siRNA-APRIL group was (59.67∓5.03)%, significantly higher than that in the other two groups [(42.33∓4.16)% and (39.67∓4.73)%, respectively, P<0.01].</p><p><b>CONCLUSION</b>Lentivirus-mediated RNAi targeting APRIL can effectively suppress the expression of APRIL in LoVo cells and enhance the chemosensitivity of the cells to 5-FU.</p>

Gefitinib enhances the radiosensitivity of nasopharyngeal carcinoma cell line CNE2 in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the radiosensitizing effect of gefitinib on nasopharyngeal carcinoma cell line CNE2 in vitro.</p><p><b>METHODS</b>Nasopharyngeal carcinoma cell line CNE2 was cultured in RP2MI 1640. MTT assay was performed to evaluate the cell proliferation changes in response to gefitinib treatment and the radiosensitizing effect of gefitinib. The cell survival curves and sensitive enhancement ratio (SERs) were obtained with a clonogenic assay. Flow cytometry analysis was applied to detect the cell cycle changes and cell apoptosis.</p><p><b>RESULTS</b>MTT assay showed that cells exposed to gefitinib and radiation had a significantly lower survival ratio compared to the cells with radiation exposure only (0.582∓0.012 vs 0.398∓0.016, P=0.002), with a SER of 1.535∓0.134. The S phase cell percentage was significantly decreased and G(2)-M phase cells increased in gefitinib plus radiation group (P=0.000), suggesting a synergistic effect of gefitinib and radiation.</p><p><b>CONCLUSION</b>Gefitinib can enhance the radiosensitivity of nasopharyngeal carcinoma CNE2 cells in vitro possibly by inhibiting cell proliferation, inducing cell apoptosis, and causing changes in the cell cycle distribution.</p>

Radiation-induced G2 phase arrest may contribute to the radioresistance of breast cancer stem cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate radiation-induced cell cycle changes of human breast cancer stem cells enriched by suspension culture.</p><p><b>METHODS</b>The tumorigenicity of human breast cancer stem cell line MCF-7 cultured in serum-free media was confirmed in NOD/SCID mice, and the radiosensitivity of the cells was tested by clone formation assay following radiation exposure. Flow cytometry was performed to evaluate radiation-induced cell cycle changes, and the protein expression of pCDC25C (ser216) was measured by Western blotting.</p><p><b>RESULTS</b>After the exposure to 2 Gy radiation, the survived fraction of the cells in suspension culture and those in adherent culture was 0.856 ∓ 0.061 and 0.783 ∓ 0.097, respectively, and the cells in suspension culture showed an obviously greater capacity of tumorigenicity in NOD/SCID mice. The radiation exposure resulted in an obvious increase in the proportion of G2 phase cells from (22.03 ∓ 2.12)% to (45.83 ∓ 2.25)% and significantly increased the expression of pCDC25C (ser216).</p><p><b>CONCLUSION</b>Radiation- induced G2 phase arrest may contribute to the resistance of the breast cancer stem cells to radiotherapy.</p>

Effects of radiosensitivity and X-ray dose on miR-7 expression in nasopharyngeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of radiosensitivity and X-ray dose on the expression of miR-7 in nasopharyngeal carcinoma (NPC) cells.</p><p><b>METHODS</b>Low radiosensitive NPC cells CNE-1 and high radiosensitive NPC cells CNE-2 were exposed to 0, 2 and 8 Gy X-ray. The total RNAs of the cell lines were extracted 10 h after radiation for reverse transcription of miR-7 and 18S rRNA by stem-loop primer and random hexamers, respectively. The non-irradiated CNE-1 cells served as the control sample and the relative quantity of the expression level was calculated after real-time PCR using SyBR green.</p><p><b>RESULTS</b>miR-7 expression differed significantly between CNE-1 and CNE-2 cells (4.49-/+3.62 vs 1.29-/+1.10, F=135.483, P<0.001). The radiation dose also significantly affected the expression of miR-7 in NPC cells (F=39.565, P<0.001). CNE-1 cells with a 2 Gy exposure had the highest expression level of miR-7, while the non-irradiated CNE-1 cells had the lowest expression. CNE-2 cells exposed to 2 Gy X-ray had the lowest expression level of miR-7 and the non-irradiated CNE-2 cells had the highest.</p><p><b>CONCLUSION</b>Radiosensitivity and radiation dose of X-ray have significant effect on the expression of miR-7 in NPC cells, indicating that miR-7 plays an important role in radioresistance of NPC cells to X-ray, and suppressed miR-7 expression may elevate the radiosensitivity of NPC cells.</p>

MicroRNA profiling in patients with hepatocellular carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the differential expression of microRNAs between human hepatocellular carcinoma (HCC) and liver cirrhosis (LC).</p><p><b>METHODS</b>The total RNA was extracted from 25 pairs of HCC and LC tissues. microRNA microarray was used to analyze the microRNA expression profiles, and validation of the microarray results was carried out by real-time quantitative RT-PCR (qRT-PCR).</p><p><b>RESULTS</b>Three microRNAs exhibited higher expression in the HCC samples than in the LC samples. In comparison with the LC samples, the HCC samples showed down-regulated expressions of 9 microRNAs. qRT-PCR verified that has-miR-122a, has-miR-199a, and has-miR-199b were downregulated in HCC, which was in agreement with the microarray results.</p><p><b>CONCLUSION</b>HCC and LC samples have significantly different microRNA expression profiles. These differentially expressed microRNAs may be involved in the pathogensis of HCC.</p>

PKC isoform selectivity and radiation-induced apoptosis of HepG2 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expressions of protein kinase C (PKC) isoforms in X-ray-exposed HepG2 cells and identify the PKC isoforms that induce radioresistance in HepG2 cells.</p><p><b>METHODS</b>Cultured HepG2 cells were divided into control group and 6 Gy radiation group for corresponding treatments. The fluorescence intensity (FI) and the percentage of positive cells were determined using flow cytometry.</p><p><b>RESULTS</b>The FI of PKCalpha and PKCdelta were 2.28 and 5.05 in the radiation group, respectively, significantly higher than those in the control group (P<0.05). The percentages of PKCalpha- and PKCdelta -positive cells were significantly higher in the radiation group than in the control group (P<0.05). The FI and the percentages of PKC zeta, gamma, epsilon, zeta positive cells were rather low and showed no significant differences between the two groups (P>0.05); PKCbeta expression was not detected in the two groups of cells. The apoptosis rates of the control and radiation groups were 1.73% and 20.90%, respectively.</p><p><b>CONCLUSION</b>PKCalpha and PKCdelta may be involved in protecting HepG2 cells from radiation-induced apoptosis.</p>

Ginsenoside Rg1 protects rat hippocampal neurons from radiation injury by regulating NOS activity / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the protective effect of ginsenoside Rg1 on cultured rat hippocampal neurons against radiation injury and explore new therapies for preventing radiation encephalopathy.</p><p><b>METHODS</b>Rat hippocampal neurons cultured for 12 days were subjected to a single-dose X-ray exposure of 30 Gy. 4',6-diamidino-2-phenylindole (DAPI) staining was used to detect the neuronal apoptosis and NOS activity kit utilized to evaluate NOS activity in the cells after the exposure.</p><p><b>RESULTS</b>Nuclear condensation was detected in (25.3-/+3.57)% of the neurons 24 h after 30 Gy X-ray exposure, a rate significantly higher than that in the control cells [(1.95-/+0.78)%, P<0.01]. In the neurons pretreated with ginsenoside Rg1, only (7.43-/+1.51)% of the cells presented with nuclear condensation after the exposure, significantly different from the rates in the control cultures and the exposed cultures (P<0.01). The NOS activity of exposed cultures was 6.46-/+0.95 U/ml, significantly higher than that in the control cultures (3.20-/+0.70 U/ml, P<0.01). The NOS activity of the neurons pretreated with ginsenoside Rg1 was 3.85-/+0.69 U/ml, significantly different from that in the control cultures (P<0.05) and the exposed cultures (P<0.01).</p><p><b>CONCLUSION</b>Ginsenoside Rg1 offers significant protective effect on rat hippocampal neurons from radiation-induced apoptosis by reducing the activity of NOS.</p>

p35 and p25 expressions and Cdk5 kinase activity in primary cultured rat hippocampal neurons with X-ray exposure / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the expressions of p35 and p25 and Cdk5 kinase activity in cultured rats hippocampal neurons following X-ray exposure to provide experimental evidence for prevention and treatment of radiation encephalopathy.</p><p><b>METHODS</b>The hippocampal neurons cultured for 12 days were subjected to a single-dose X-ray exposure of 30 Gy. Western blotting was used to detect the p35 and p25 protein levels, and the effect of pretreatment with roscovitine, a Cdk5 inhibitor, on the apoptosis of the hippocampal neurons following the exposure was examined with 4',6-diamidino-2-phenylindole (DAPI) staining.</p><p><b>RESULTS</b>The protein level of p35 increased significantly 3.5 and 4 h after the irradiation by 1.51-/+0.13 and 1.45-/+0.14 folds in comparison with the control level, respectively (P<0.01), and the p25 level increased significantly 6 h after irradiation by 1.62-/+0.28 folds (P<0.05). Nuclear condensation occurred in (24.8-/+3.97)% of the neurons 24 h after 30 Gy X-ray exposure, a rate significantly higher than that in the nonexposed cells [(1.82-/+1.08)%, P<0.01) and that in roscovitine-pretreated neurons [(7.74-/+2.27)%, P<0.01).</p><p><b>CONCLUSION</b>X-ray exposure activates Cdk5 by increasing the p35 and p25 expressions in rat hippocampal neurons, and inhibition of Cdk5 activity with roscovitine can significantly protect the neurons from apoptosis.</p>

Rna interference of annexin II gene in PC3 cells by using small interference RNA synthesized with in vitro transcription / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To silence annexin II gene expression by using small interference RNA (siRNA) in prostate cancer cell line PC3.</p><p><b>METHODS</b>For in vitro transcription, four sequences of 29-nucleotide DNA template oligonucleotides were designed, and one pair of the sequences were complementary to annexin II gene. The other pair was negative control. The 8 nucleotides at the 3' end of each oligonucleotide were complementary to the T7 Promoter Primer. The sense and antisense siRNA templates were transcribed by T7 RNA polymerase and the resulting RNA transcripts were hybridized to create dsRNA. The siRNA was transfected into prostate cancer cell PC3. For assaying the efficiency of siRNA, confocal microscopy, Northern blotting, and Western blotting were employed to examine the expression of annexin II protein and its mRNA. 3H thymidine was used to measure DNA synthesis.</p><p><b>RESULTS</b>The siRNA sequence specific to annexin II gene was capable of inhibiting the expression of annexin II protein and its mRNA. And cellular DNA synthesis was significantly reduced in siRNA transfected cells.</p><p><b>CONCLUSIONS</b>The protocol for the synthesis of siRNA by T7 RNA polymerase is feasible. Annexin II might be involved in DNA synthesis.</p>

Expression of PCNA and GST-pi after stereotactic irradiation for liver cirrhosis and hepatocarcinoma in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the changes of the cytokines following stereotactic irradiation for hepatocarcinoma with cirrhosis in rabbits.</p><p><b>METHODS</b>Sixteen rabbits with liver cirrhosis and hepatocarcinoma (experimental group) were randomized into two equal groups to receive stereotactic irradiation at single dose of 20 and 30 Gy, respectively. Eight rabbits with hepatocarcinoma (control group) were divided into two equal groups and treated in identical manner. All the rabbits were killed 3 weeks after irradiation, and EV two-step method was used to observe the cytokine changes of proliferating cell nuclear antigen (PCNA) and glutathione S-transferase pi (GST-pi) after irradiation.</p><p><b>RESULTS</b>After irradiation, PCNA and GST-pi expression showed significant difference in the adjacent liver tissue between the experimental and control rabbits with irradiation at 20 Gy (P=0.010), but not with the irradiation dose of 30 Gy (P=1.000). Irradiation at different doses resulted in significant difference in the cytokine expression in the experimental rabbits (P=0.010). In the liver tissue exposed to irradiation, different irradiation doses resulted in significant difference in PCNA and GST-pi protein expression (P=0.010).</p><p><b>CONCLUSIONS</b>For hepatocarcinoma with cirrhosis in rabbits, radiation at the single dose of 30 Gy produces better response than 20 Gy, and PCNA and GST-pi may serve as good indexes for evaluating the therapeutic effect.</p>