Effect of captopril on AGS nude mouse model of gastric cancer

AIM: To observe the effect of captopril on the genesis and development of gastric cancer, and to explore its clinical treatment feasibility for gastric cancer. METHODS: The human gastric cancer cell line AGS was used to establish a tumor model in nude mice, and the model mice were randomly divided into 3 groups: positive control (5-fluorouracil) group, normal control (saline) group and experimental (captopril) group. After intraperitoneal injection or intragastric administration of the drugs, the tumor growth curve was determined, and the tumor tissues were also sampled to detect the expression of Ki-67, STAT3, Bax and Bcl-2 by real-time quantitative PCR and immunohistochemistry. The apoptosis was detected by TUNEL+DAPI staining. RESULTS: The tumor growth curve showed that the tumor model in the nude mice was successfully established. The tumor volumes among groups showed significantly different after 14 d growth. The increase in the tumor volume in normal control group was significantly faster than that in the other two groups, and that in positive control group was the slowest. The expression of Bax in captopril group increased, and the expression of STAT3, Ki-67 and Bcl-2 was reduced as compared with normal control group and positive control group. Compared with normal control group, the apoptotic rate increased significantly, and the protein expression of p-STAT3 and STAT3 decreased obviously in positive control group and captopril group. CONCLUSION: With better feasibility, angiotensin-converting enzyme inhibitor captopril has a significant effect on treating gastric cancer in the AGS nude mouse model by regulating the expression of STAT3, Bax, Bcl-2 and Ki-67 to accelerate the apoptosis of cancer cells, thus inhibiting tumor growth.     

Inhibition of 17-DMAG on VEGF expression in transplanted human gastric cancer in nude mice

AIM: To observe the anti-tumor effects of heat shock protein 90(HSP90) inhibitor 17-dimethylaminoethylamino-17 demethoxygeldanamycin (17-DMAG) on the tumor growth and angiogenesis in implanted gastric cancer nude mouse model. METHODS: Human gastric cancer cell HGC-27 was subcutaneous inoculation into the nude mice to develop a tumor model. Ten days later, 24 mice with implanted tumor were randomly divided into 3 groups: 17-DMAG group (receiving 17-DMAG at dose of 25 mg/kg), control group (treated with NS at dose of 10 mL/kg) and 5-fluorouracil(5-FU) group (treated with 5-FU at dose of 20 mg/kg). Four weeks after treatment, the tumor volume and weight, and the inhibitory rates of tumor growth were evaluated. In the meantime, the expression of CD31 was detected by immunohistochemical staining. The expression of vascular endothelial growth factor (VEGF) was determined by Western blotting. RESULTS: The size of xenografts in 17-DMAG treatment group was (288.10±23.32)mm³, and that in 5-FU treatment group was (366.37±26.42)mm³, both were significantly smaller than that in control group (957.66±117.51)mm³. The tumor weight in 17-DMAG treatment group was (0.41±0.02)g, significantly less than that in control group (1.12±0.08)g. The inhibitory rate of 17-DMAG was 63%. A significant decease of MVD in 17-DMAG group (21.72±1.24) was observed as compared to 5-FU group (36.70±1.51) and control group (37.78±1.68). The expression of VEGF in 17-DMAG group (15.39±4.37) was significantly lower than that in 5-FU group (26.11±6.26) and control group (36.45±7.45). CONCLUSION: HSP90 inhibitor 17-DMAG suppresses the expression of VEGF and the angiogenesis of the gastric cancer to inhibit the tumor growth.     

Apoptosis of implanted tumor of human primary gastric cancer cells in nude mice induced by resveratrol

AIM: To investigate the molecular mechanism of the apoptosis of implanted tumor of human primary gastric cancer cells in nude mice induced by resveratrol. METHODS: Human primary gastric cancer cells were planted into nude mice to establish the cancer model. Resveratrol at different doses were injected near the carcinoma on the nude mice. After treatment, transmission electron microscope and TUNEL staining method were used to detect the apoptosis of implanted tumor cells. Immunohistochemical staining and RT-PCR were used to detect the expression of apoptosis-related genes bcl-2 and bax in implanted tumor. RESULTS: Resveratrol significantly inhibited carcinoma growth when it was injected near the carcinoma. The apoptotic cells in implanted tumor induced by resveratrol were detected by transmission electron microscope and TUNEL staining, immunohistochemical staining and RT-PCR showed resveratrol inhibited bcl-2 expression and increased bax expression in human primary gastric cancer cells. CONCLUSION: Resveratrol inhibits implanted tumor of human primary gastric cancer cells in nude mice through inducing apoptosis. This apoptosis may be mediated by down-regulation of bcl-2 expression and up-regulation of bax expression.     

The anticancer activity of genistein on implanted tumor of human primary gastric carcinoma cells in nude mice

AIM: To investigate the apoptosis of implanted tumor of primary human gastric cancer cells in nude mice induced by genistein and the relation between this apoptosis and expression of bcl-2 and bax.METHODS: Establishing a transplanted tumor model by injecting human primary gastric cancer cells into subcutaneous tissue of nude mice.The different doses of genistein (0.5mg/kg,1mg/kg and 1.5 mg/kg ) were directly injected beside tumor body respectively,for six times at an interval of two days.Then changes of tumor volume were measured continuously and tumor inhibition rate of each group was calculated.We observed the morphologic alteration by electron microscope,measured the apoptotic rate by TUNEL staining method,detected the expression of apoptosis-regulated gene bcl-2 and bax by immunohistochemical staining and RT-PCR.RESULTS: Genistein could significantly inhibit carcinoma growth when it was injected near the carcinoma.Genistein induced implanted tumors cells to undergo apoptosis with apoptotic characteristics by transmission electron microscope.The apoptosis index of above three groups was increased progressively.Positive rate of Bcl-2 protein of above three groups was decreased progressively and positive rate of Bax protein of above three groups was increased progressively by immunohistochemical staining.The density of bcl-2 mRNA decreased progressively and the density of bax mRNA increased progressively with elongation of time by RT-PCR.CONCLUSION: Genistein is able to induce the apoptosis of transplanted tumor cells.This apoptosis may be mediated by down-regulating bcl-2 and up-regulating bax mRNA and its protein.     

Effects of MAGEA3 inhibition by shRNA on apoptosis in human hepatocellular cancer cells

AIM:To investigate the inhibitory effect of vector-based RNA interference ( RNAi) on the expression of melanoma associated antigen A3 (MAGEA3) protein in hepatocellular carcinoma cells and on apotposis of hepatocellular carcinoma cells. METHODS:A vector for transcribing specific small hairpin RNA ( shRNA) targeting MAGEA3 gene was constructed ,introduced into hepatocellular carcinoma MEL-ED1 cells by Lipofectamine 2000. The MAGEA3 protein and mRNA expression levels of MEL-ED1 cells were detected by Western blotting and RT-PCR, respectively. The cell apoptosis was studied by DNA fragmentation, electron microscopy ，TUNEL assay, and annexin V/PI staining. RESULTS:The vector of RNA interference was successfully constructed and MAGEA3 expression was descreased significantly in MEL-ED1 cells. After the shRNA expression vector was transfected into the MEL-ED1 cells, the expression of MAGEA3 gene was inhibited significantly ( by 90% ). DNA fragmentation，electron microscopy and TUNEL assay showed classic apoptosis characters in the MEL-ED1 cells transfected with pSilencer-MAGEA3 plasmid with an apoptosis rate of 21.41% ±1.98%, significantly higher than those in the negative control group transfected with pSilencer-neo and in the non-transfected group (both P<0.01). CONCLUSION:The specific small hairpin RNA targeting MAGEA3 mRNA can inhibit the expression of MAGEA3 and cause apoptosis of hepatocellular carcinoma cells , which suggests inhibitory effect of MAGEA3 on apoptosis in cancer and provides an experimental basis for treating human tumors with RNAi.     

Effect of HGF gene transfection on human lymphoma xenografts in nude mice

AIM：To explore the promotion effect of hepatocyte growth factor (HGF) gene transfection on human lymphoma xenografts in nude mice. METHODS：The model of human lymphoma xenograft in nude mice was established by transplantation of Raji cells, which were transfected with recombinant plasmid pVITRO2-HGF harboring the HGF gene. The body weight of the nude mice and the tumor size were dynamically monitored and the tumor tissues were obtained after 8 weeks. Additionally, the methods of terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) and immunohistochemistry were used to detect the apoptotic index (AI) and microvessel density (MVD). RESULTS：The success rate of the human lymphoma xenografts in nude mice was 96.7%. The tumor volume in HGF transfection group was significantly greater than that in HGF transfection+VP-16 group and control groups (non-transfection group and empty vector group). The tumor volume in HGF transfection+VP-16 group was also bigger than that in control groups. No difference of the tumor volume between non-transfection group and empty vector group was observed. AI in HGF transfection group was substantially lower than that in control groups. AI in HGF transfection+VP-16 group showed a little higher than that in HGF transfection group, yet was still lower than that in control groups. MVD in HGF transfection group was extraordinary higher than that in control groups, but decreased after VP-16 induction (P<0.01), which was still higher than that in control groups. CONCLUSION：HGF gene transfection significantly promotes the growth of human lymphoma xenografts in nude mice and substantially inhibits the apoptosis presumably owing to promoting tumor angiogenesis and inhibiting tumor cell apoptosis.     

Inhibition of survivin expression in BGC-823 cells by RNA interference

AIM: To investigate the feasibility and specificity of gastric carcinoma gene therapy by utilizing RNA interference (RNAi) to inhibit survivin expression in vitro and in vivo. METHODS: Small interference RNA (siRNA) homologous to survivin was designed. pTZU6+1-siRNA-survivin vector was constructed and transfected into BGC-823 cells. The transplanted BGC-823 tumor in nude mice was established to induce RNAi. The changes of survivin gene expression, tumor cell cycle and cell apoptosis were detected by flow cytometry, RT-PCR, Western blotting, immunochemistry and TUNEL. RESULTS: The expression of survivin was obviously inhibited by RNAi in vitro. The phase of cell cycle indicated the reduction of S phase, while G1/G0 phase increased. Cell apoptosis was obvious. Both the mRNA level and the protein expression of survivin decreased obviously. The tumor size reduced after treated with pTZU6+1-siRNA-survivin vector in vivo. The expression of survivin decreased in siRNA treatment group. In contrast, little change in control group in vitro and in vivo was observed. CONCLUSION: RNA interference down-regulates survivin gene expression, inhibits BGC-823 cell proliferation and induces cell apoptosis with good specificity, which may be a possible new approach for neoplasm gene therapy.     

The inhibitory action of rhTRAIL on mouse breast carcinoma

AIM:To explore the inhibitory action of recombinant human tumor necrosis factor-related apoptosis-inducing ligand(rhTRAIL) on mouse breast cancer.METHODS:Each mouse was inoculated 0.2 mL (1×106) D2F2 cells subcutaneously in the right lower limb and they were divided into five groups randomly.The control group was infused PBS 0.2 mL, while the low-dose, medium, high groups received purified rhTRAIL 2.5 mg/kg, 5.0 mg/kg, 10.0 mg/kg, respectively, the positive group was administered cyclophosphamide 30.0 mg/kg.Every group was operated by peritoneal injection once a day for fifteen days.The mice were weighed every day.The growth state was viewed and the size of the tumor was measured every 3 d to calculate the tumor volume and tumor suppression rate.All mice were killed after 15 d.The pathologic changes of the tumor were observed under light-microscopy and electronic microscopy.The cell cycle and apoptosis index of D2F2 cells were analyzed by flow cytometry.RESULTS: The body weight and tumor volume in low-dose, medium, high groups were lower than those in control group and the restriction effect was more significant than that in the control group (P<0.01).The body weight and tumor volume in low-dose, medium, high groups decreased with the increase in rhTRAIL concentration.The difference was significant (P<0.01).Both apoptosis and necrosis of tumor cells were observed in low-dose, medium, high groups.The area of cell apoptosis was large and most area didnt have tumor cells but only apoptotic bodise.The results of flow cytometry showed that rhTRAIL induced the apoptosis of D2F2 cells, and the apoptosis rates were 7.56 %, 21.37 %, 27.16 % respectively when rhTRAIL doses were 0.25 mg/L, 0.5 mg/L, 1.0 mg/L.Significant differences among three groups were observed (P<0.05).CONCLUSION:rhTRAIL induces apoptosis in mouse breast cancer cells and even the necrosis of tumor cells.rhTRAIL has significant effect on inhibiting the growth of D2F2 cells.     

Effect of N-cadherin knock-down on tumor formation of EC9706 cells in nude mice

AIM: To explore the effect of N-cadherin knock-down on the biological behavior of EC9706 cells in vivo.METHODS: The control vector pEGFP-MSCVneo and recombinant retroviral vector pMSCVneo/N-cadherin plasmids were transfected into esophageal squamous cell carcinoma(ESCC) cell line EC9706 according to the manufacturer's instructions. Stable EC9706 cell clones were selected using selection medium containing G418. Untreated EC9706 cells, control vector-transfected EC9706 cells and N-cadherin RNAi-transfected EC9706 cells were inoculated subcutaneously into the right flank of BALB/c mice (5 for each group), respectively. When tumors became palpable, the diameters of the tumors were measured with a caliper each week after subcutaneous implantation, and the volume (mm³) and weight (g) of the tumors were also calculated. Immunohistochemistry and Western blotting were employed to examine the expression levels of E-cadherin, N-cadherin and MMP-9 in the tumor tissues. The cell apoptosis was analyzed by TUNEL method.RESULTS: Compared with untreated group and control vector group, there was an obvious decrease in the volumes and weights of the tumors in N-cadherin RNAi group (P<0.05). No difference of E-cadherin expression in the 3 groups was observed. However, the expression of N-cadherin and MMP-9 in N-cadherin RNAi group was apparently reduced, and the positive number of cell apoptosis was obviously increased in N-cadherin RNAi group (106.81±6.47) as compared with that in untreated group (51.55±4.68) and control vector group (54.17±5.26). CONCLUSION: N-cadherin knock-down inhibits the tumor formation of EC9706 cells in nude mice by decreasing MMP-9 expression, resulting in less degradation of ECM and less aggression of the cancer cells. N-cadherin is an important factor in the progression and metastasis of ESCC,and may serve as a potential molecular target for biotherapy of ESCC.     

Apoptosis of colorectal cancer cells transfected with human mutant p27

AIM: To study the inducing effect of human mutant p27 gene on apoptosis of the colorectal cancer cells. METHODS: The recombinant adenovirus Ad-p27mt was constructed to infect the colorectal cancer cell SW480. The inducing effect of Ad-p27mt on apoptosis in colorectal cancer cells was measured by flow cytometry, DNA fragment analysis and TUNEL method. RESULTS: Ad-p27mt was successfully constructed. When the multiplicity of infection (MOI) was ≥50, the infection efficiency reached 100%. After 24 h of infection, there was an apoptotic hypodiploid peak observed by flow cytometry before G1 and there were apoptotic characteristic bands in the DNA electrophoresis. The apoptotic index detected by TUNEL method was 82.6±3.2 (Ad-p27mt group) and 5.0±3.5 (control group), respectively, the difference of which was significant (P<0.01). CONCLUSION: Human mutant p27 gene transfection effectively induces apoptosis in the colorectal cancer cells.     

Role of bcl-2 gene expression in inhabition of hepatocellular carcinoma by genistein in nude mice

AIM:To probe into the role of 1, 4, 5 - trisphosphate inositol (IP3) and bcl-2 gene expression in inhibiting hepatocellular carcinoma of nude mice by genistein. METHODS:Animals with hepatocellular carcinoma were treated with genistein 1 mg·kg-1·d-1 (ip) for 3 weeks. The volume and weight of tumaor were measured. IP3, bcl-2 mRNA, Bcl-2 protein were assayed by IP3-［3H］ Birtrak assay, RT-PCR, Western blotting, respectively. RESULTS:The tumor volume and weight of animals treated with genistein were lower than those in control (42.7mm3±27.8mm3 vs 52.3mm3±26.5mm3, 42.7mg±27.8 mg vs 91.3mg±31.4 mg). IP3 content was lower than that in control ［(13.4±1.4)nmol/g protein vs (35.3±6.6)nmol/g protein］. bcl-2 mRNA expression was lower in group treated with genistein than that in control (RI which was the gray degree multiply area of bcl-2 / the gray degree multiply area of β-actin 0.48±0.02 vs 0.56±0.15). Bcl-2 protein expression was lower in group treated with genistein than that in control (RI 1.69±0.52 vs 1.37±0.48). CONCLUSION:Genistein inhibits growth of transplanted hepatocellular carcinoma in nude mouse liver by reducing IP3 production and down-regulating bcl-2 gene expression.     

Resveratrol induces apoptosis in human primary gastric carcinoma cells

AIM: To investigate the apoptosis in primary gastric cancer cells induced by resveratrol, and the relation between this apoptosis and expression of bcl-2 and bax. METHODS: In in vitro experiments, MTT assay was used to determine the cell growth inhibitory rate. Transmission electron microscopy and TUNEL staining were used to quantitatively and qualitively detect the apoptosis of primary gastric cancer cells before and after the resveratrol treatment. Immunohistochemical staining and RT-PCR was used to detect the expression of apoptosis-regulated gene bcl-2 and bax. RESULTS: Resveratrol inhibited the growth of primary gastric cancer cells in a dose- and time-dependent manner. Resveratrol induced primary gastric cancer cells to undergo apoptosis with typically apoptotic characteristics. TUNEL assay showed that after the treatment of primary gastric cancer cells with resveratrol for 24, 48, 72, 96 hours, the apoptotic indexs were 4.93%±0.19%, 16.74%±0.43%, 27.88%±0.36%, 36.84%±1.07% respectively. Immunohistochemical staining showed that after the treatment of primary gastric cancer cells with resveratrol for 24, 48, 72, 96 hours, the positive rates of Bcl-2 proteins were 20.68%±0.49%, 10.84%±0.33%, 6.80%±0.34%, 3.91%±0.15% and the positive rates of Bax proteins were 19.79%±0.98%, 30.74%±0.85%, 40.14%±1.17%, 60.08%±1.64%. After exposed to resveratrol for 24 h, 48 h, 72 h and 96 h, the density of bcl-2 mRNA decreased progressively with elongation of time and the density of bax mRNA increased progressively with elongation of time by RT-PCR. CONCLUSION: Resveratrol is able to induce the apoptosis in primary gastric cancer. This apoptosis may be mediated by down-regulation of Bcl-2 and up-regulation of Bax.     

Triptolide induces apoptosis of rat synoviocytes in collagen-induced arthritis

AIM: To determine whether triptolide induce apoptosis of synovial cells in collagen-induced arthritis (CIA) in rats. METHODS: The male Wistar rats were used to make CIA models by immunized with Bovine collagen Ⅱ (BCⅡ) in Freund's complete adjuvant (FCA). A total of 20 CIA rats were randomly divided into 2 groups, triptolide group (10 rats) and CIA control group (10 rats). Triptolide group were administered with triptolide at 40 μg/kg body weight intramuscularly every three days. CIA control group and another 10 age-matched normal rats were given normal saline instead. The rats were sacrificed on the 31st day after the triptolide administration. The pieces of synovium of the rat knee joints were harvested. The synovium was examined by HE staining and electron microscope. The apoptosis was tested by TUNEL and flow cytometer. RESULTS: The earlier phase of apoptotic synoviocytes were observed under the electron microscope. The flow cytometry showed that the percentage of the apoptotic cells was (3.98±1.16)% in the triptolide group, (1.83±0.82)% in the CIA control group, and (0.87±0.24)% in the normal group (P<0.01: triptolide vs control group). While the percentage of the cells in DNA synthesis phase was (3.3±1.2)% in the triptolide group, (8.0±1.4)% in the CIA control group, and (3.4±0.7)% in the normal group. There is significantly different in the apoptosis changes between the triptolide group and the CIA control group (P<0.01: triptolide vs CIA control group). The TUNEL labeling demonstrated that the percentage of the apoptotic cells was (4.5±1.0)% in the triptolide group, (2.2±1.0)% in the CIA control group, and (1.0±0.4)% in the normal group. The difference of apoptotic rate between the triptolide group and the CIA control group is significant (P<0.01). CONCLUSION: This study demonstrates that triptolide can induce apoptosis in CIA rats, which may be one of the mechanisms that triptolide treats the rheumatoid arthritis.     

Effect of pentoxifylline on caspases expression in islet beta-cells of NOD mice

AIM: To investigate the intervention effect of pentoxifylline (PTX) on type 1 diabetes mellitus in non-obese diabetic (NOD)mice and explore its possible mechanism.METHODS: Eight-week-old NOD mice were treated with PTX to investigate the incidence of cyclophosphamide accelerating diabetes.The apoptosis of beta-cells was detected by TUNEL,the expressions of caspase-3 in islet of the NOD mice was checked by immunohistochemistry and the expressions of caspase-8 was determined by RT-PCR.RESULTS: The incidence of diabetes in PTX group was 40.63%,which was obviously lower than 69.70% in the control group (P<0.05). Apoptosis index of beta-cells was 4.80% in PTX group and was 9.04% in control group,of which the former was lower than the latter (P<0.01).The expression of caspase-3 in islet of the mice in PTX group was much lower than that in control group,and the expression of caspase-8 mRNA in pancreas in PTX group were also markedly lower than that in control group (P<0.01).CONCLUSION: PTX prevents NOD mice from developing type 1 diabetes,which may be related to the downregulation of caspase-3 and caspase-8 expressions in pancreas and then the decrease of beta-cell apoptosis.     

Inhibitory effect of survivin antisense oligodeoxyribonucleotide combined with DDP in nude mice bearing human osteosarcoma xenograft

AIM:To investigate the feasibility and its mechanisms of improving therapeutic effect by antisense gene therapy combined with chemotherapy in osteosarcoma. METHODS:The human osteosarcoma implanted tumor model in the nude mice was established. By intratumoral injection and abdominal cavity administration, the tumor bearing mice were treated with survivin ASODN in combination with diamminedichloroplatinum (DDP) for a week. Comparison with each single-agent therapy and control group was performed in aspects such as tumor growth condition, pathological changes of tumor tissues;survivin protein expression in tumor tissues by immunohistochemistry, survivin mRNA expression levels by RT-PCR method and tumor apoptosis by Tdt-mediated dUTP nick end labeling (TUNEL). RESULTS:All nude mice survived the therapy. As compared with the control group, the antisense gene therapy group presented synchronous decrease in survivin mRNA and protein expression;all therapy group displayed tumor growth inhibition and cell apoptosis with different extent;while in contrast to single-agent therapy group, the combined therapy group showed stronger inhibition of tumor growth and abundant tumor cell apoptosis with the highest apoptotic rate. CONCLUSION:Synergistic effect was achieved by combination of DDP with ASODN that may overcome drug resistant of DDP and the combined strategy may shed new light on the cancer therapy.     

Effect of specific hTERT-siRNA on growth of human tongue cancer cells in vivo and in vitro

AIM: To investigate the effect and mechanisms of siRNA-hTERT-induced inhibition of Tca8113 tongue cancer cells in vitro and in vivo. METHODS: A small interference RNA (siRNA) targeting to hTERT mRNA (siRNA-hTERT1) was constructed. The siRNA was transfected into Tca8113 tongue cancer cells in vivo and in vitro with cationic liposome. A non-specific siRNA (siRNA-hTERT2) and non-treatment were used as negative control group and blank group. The cell growth in vitro was detected by MTT method. The cell apoptosis in vitro was analyzed by flow cytometry. The effect of siRNA-hTERT1 on xenografts in nude mice was observed by determining the tumor size. The cell apoptosis in xenografts was analyzed by Hoechst staining. The expressions of hTERT mRNA in vitro and in vivo were detected by RT- PCR. RESULTS: The inhibition rates of cell growth in vitro 72 h after siRNA-hTERT1 treatment was 47.2％, significantly higher than that in siRNA-hTERT2 treatment group (2.6％, P<0.01). The cell apoptosis rate was 27.30%±0.18% in vitro, significantly increased at 48 h after transfection of siRNA-hTERT1, compared to negative control group and blank group (P<0.01). The size of xenografts in siRNA-hTERT1 treatment group was (298.8±138.7)mm3, significantly smaller than that in siRNA-hTERT2 treatment group and blank group (495.1±151.6)mm3 and (506.8±207.4)mm3, the inhibition rate was 40.0% (P<0.01). The numbers of apoptotic cells in xenografts significantly increased after transfection of siRNA-hTERT1, compared to negative control group and blank group (P<0.01). Compared to negative control group and blank group, the expression of hTERT mRNA in Tca8113 tongue cancer cells in vitro and in vivo was inhibited by siRNA-hTERT1. CONCLUSION: siRNA-hTERT1 powerfully inhibits the growth of Tca8113 tongue cancer cells in vitro and in vivo. The specific inhibition of hTERT mRNA expression and cell apoptosis may be its main mechanisms.     

Effects of RNA interference of FABP5 on subcutaneous tumor of human hepatocellular carcinoma cell line HepG 2 transplanted in nude mice

AIM: To investigate the effect of recombinant lentiviral vector for RNA interference (RNAi) on the expression of fatty acid-binding protein 5 (FABP5) gene in hepatocellular carcinoma HepG2 cells and tumor formation in nude mice.METHODS: RNAi lentiviral vector was used in the experiment. Human hepatocellular carcinoma HepG2 cells were divided into 3 groups:the HepG2 cells in experimental group were transfected with the recombinant lentivirirus vector LV-shRNA-FABP5, the cells in negative control group were transfected with a control lentiviral vector LV-shRNA-NC, and the cells in normal control group were without any treatment. The nude mice were randomly divided into 3 groups. The growth of the transplanted tumor cells in the nude mice was observed. The tumor growth curve, volume and weight were determined 4 weeks after the cell inoculation. The expression of FABP5 was detected by real-time PCR, Western blot and immunohistochemical staining.RESULTS: Transfection of the lentiviral vector FABP5-shRNA obviously reduced FABP5 expression in the HepG2 cells. Tumor formation was all positive in the 3 groups of the nude mice inoculated with the tumor cells. Compared with normal control group and negative control group, the tumor growth slowed significantly in experimental group with smaller volume and weight. FABP5 expression in the transplanted tumor tissues was significantly down-regulated at mRNA and protein levels in experimental group as compared with normal control group and negative control group.CONCLUSION: RNAi-induced down-regulation of FABP5 effectively inhibits the growth of transplanted hepatocellular carcinoma, suggesting that FABP5 gene may be an effective target for gene therapy in treating liver cancer.     

Combination of Treg inhibition and intratumoral transfection of Ad.GM-CSF enhances the chemotherapeutic effect of doxorubicin against hepatocellular carcinoma

AIM: To explore the possibility that combination of regulatory T-cell (Treg) inhibition and intratumoral transfection of Ad.GM-CSF enhances the chemotherapeutic effect of doxorubicin against hepatocellular carcinoma (HCC). METHODS: C57BL/6J subcutaneous HCC model was established. The mice were randomly divided into 6 groups with 12 mice in each group when the tumor volume reached to 100-150 mm³: control group, cyclophosphamide(CTX) group, doxorubicin (DOX) group, Ad.GM-CSF group, CTX+DOX group and CTX+DOX+Ad.GM-CSF group. Four mice in each group were sacrificed for spleen cytotoxic T-cell(CTL) activity assay and tumor tissue histological examination 5 d after the final therapy. Eight mice in each group were examined for tumor growth and survival. RESULTS: CTX enhanced the chemotherapeutic effect of doxorubicin against HCC by inhibiting the tumor growth (P<0.05) and prolonging the mice survival (62.13 d±4.21 d vs 79.88 d±9.00 d, P<0.05), which was significantly strengthened by the combined use of Ad.GM-CSF (79.88 d±9.00 d vs 106.13 d±5.23 d, P<0.01). Compared with other groups, more tumor necrosis in tumor specimens and more infiltration of CD8⁺ T-lymphocytes in CTX+DOX+Ad.GM-CSF group were observed. Furthermore, the spleen cytotoxic T-cell(CTL) activity was significantly improved (P<0.05). CONCLUSION: Doxorubicin-based chemotherapy and immunotherapy by the method of Treg inhibition combined with intratumoral transfection of Ad.GM-CSF have synergistic effect against HCC.     

Effect of andrographolide on oral squamous cell carcinogenesis

AIM：To study the effect of andrographolide (Andro) on oral squamous cell carcinogenesis. METHODS：Chemical-induced hamster buccal pouch cancer model was used. The tumor cell proliferation, apoptosis and microvessel density (MVD) were detected by immunohistochemical staining. RESULTS：Compared with control group, the tumor volume, MVD and tumor cell proliferation in Andro group were significantly decreased. The cell apoptotic cell number in Andro group was higher than that in control group. Caspase-3 was also activated in Andro group. CONCLUSION:Andro inhibits tumor growth by suppressing proliferation, decreasing MVD and promoting apoptosis in the hamster buccal pouch. Furthermore, Andro promotes tumor cell apoptosis through caspase-3 pathway.     

Effect of γ radioactive stent on proliferation and apoptosis of smooth muscle cells

AIM: To observe effect of γ radioactive ［103Pd］ stent on the proliferation and apoptosis of smooth muscle cells, the mechanism of radioactive stent preventing in-stent restenosis was explored. METHODS: Fifty male New Zealand rabbits were randomized into stent group and ［103Pd］ stent group. Control group was set up. The materials were harvested on 3, 7, 14, 28, 56 days after operation and the following investigation were carried out, including pathomorphology, immunohistochemistry, apoptosis (TUNEL) and in situ hybridization studies.RESULTS: ① The severity of the stenosis in ［103Pd］ stent group was less severe than that in stent group. It was most obvious on 56 th day (P<0.01). ② The expression of proliferating cell nuclear antigen(PCNA) of ［103Pd］ stent group was lower than that in stent group on 3 to 28 days. It was most obvious on 7th day, 16.35%±0.79% vs 24.36±0.55% (P<0.01). ③ TUNEL method showed that the ［103Pd］ stent group had much more apoptosis of VSMC than that in stent group. The highest rate of apoptosis appeared on day 7, 14.72%±0.53% vs 12.42%±1.13% (P<0.01). ④ By calculating the ratio of PCNA/apoptosis (P〖KG*6〗∶〖KG-*2〗A), a much lower ratio was seen in ［103Pd］-stent groups than that in stent group at 3 to 28 days. There was significant statistic difference (P<0.05). ⑤ For bcl-2/bax ratio, the result in ［103Pd］-stent group was lower than that in stent group at 3 to 28 days. There was significant statistic difference (P<0.05).CONCLUSION: γ radioactive stent inhibits the proliferation and accelerates apoptosis of injured media vascular smooth muscle cells. It decreases the ratio of proliferation to apoptosis and relieves the severity of restenosis.