OBJECTIVE: Plant-derived cytotoxic transgene expression, such as trichosanthin (tcs), regulated by recombinant adeno-associated virus (rAAV) vector is a promising cancer gene therapy. However, the cytotoxic transgene can hamper the vector production in the rAAV producer cell line, human embryonic kidney (HEK293) cells. Here, we explored microRNA-122 (miR122) and its target sequence to limit the expression of the cytotoxic gene in the rAAV producer cells. METHODS: A miR122 target (122T) sequence was incorporated into the 3' untranslated region of the tcs cDNA sequence. The firefly luciferase (fluc) transgene was used as an appropriate control. Cell line HEK293-mir122 was generated by the lentiviral vector-mediated genome integration of the mir122 gene in parental HEK293 cells. The effects of miR122 overexpression on cell growth, transgene expression, and rAAV production were determined. RESULTS: The presence of 122T sequence significantly reduced transgene expression in the miR122-enriched Huh7 cell line (in vitro), fresh human hepatocytes (ex vivo), and mouse liver (in vivo). Also, the normal liver physiology was unaffected by delivery of 122T sequence by rAAV vectors. Compared with the parental cells, the miR122-overexpressing HEK293-mir122 cell line showed similar cell growth rate and expression of transgene without 122T, as well as the ability to produce liver-targeting rAAV vectors. Fascinatingly, the yield of rAAV vectors carrying the tcs-122T gene was increased by 77.7-fold in HEK293-mir122 cells. Moreover, the tcs-122T-containing rAAV vectors significantly reduced the proliferation of hepatocellular carcinoma cells without affecting the normal liver cells. CONCLUSION HEK293-mir122 cells along with the 122T sequence provide a potential tool to attenuate the cytotoxic transgene expression, such as tcs, during rAAV vector production.
Animals ; Dependovirus/genetics* ; Genetic Therapy ; Genetic Vectors/genetics* ; HEK293 Cells ; Humans ; Mice ; MicroRNAs/genetics* ; Trichosanthin

PURPOSE: Reduced brain glucose metabolism and basal forebrain cholinergic neuron degeneration are common features of Alzheimer's disease and have been correlated with memory function. Although regions representing glucose hypometabolism in patients with Alzheimer's disease are targets of cholinergic basal forebrain neurons, the interaction between cholinergic denervation and glucose hypometabolism is still unclear. The aim of the present study was to evaluate glucose metabolism changes caused by cholinergic deficits. MATERIALS AND METHODS: We lesioned basal forebrain cholinergic neurons in rats using 192 immunoglobulin G-saporin. After 3 weeks, lesioned animals underwent water maze testing or were analyzed by 18F-2-fluoro-2-deoxyglucose positron emission tomography. RESULTS: During water maze probe testing, performance of the lesioned group decreased with respect to time spent in the target quadrant and platform zone. Cingulate cortex glucose metabolism in the lesioned group decreased, compared with the normal group. Additionally, acetylcholinesterase activity and glutamate decarboxylase 65/67 expression declined in the cingulate cortex. CONCLUSION: Our results reveal that spatial memory impairment in animals with selective basal forebrain cholinergic neuron damage is associated with a functional decline in the GABAergic and cholinergic system associated with cingulate cortex glucose hypometabolism.
Acetylcholine/metabolism ; Alzheimer Disease ; Animals ; Antibodies, Monoclonal/*pharmacology ; Basal Forebrain/*drug effects/metabolism ; Cholinergic Agents/administration & dosage/*pharmacology ; Cholinergic Neurons/*drug effects/metabolism ; Fluorodeoxyglucose F18 ; GABAergic Neurons/*drug effects/metabolism ; Glucose/*metabolism ; Gyrus Cinguli/*drug effects/metabolism ; Humans ; Injections ; Maze Learning ; Motor Activity/physiology ; Positron-Emission Tomography ; Rats ; Ribosome Inactivating Proteins, Type 1/*pharmacology

OBJECTIVELittle effort has been made to study the protein-encoding genes isolated from traditional Chinese medicine (TCM) drugs, and the delivery of these genes into malignant cells through recombinant adeno-associated virus (rAAV) vectors has not been attempted.

METHODSWe synthesized the cDNAs of five known cytotoxic proteins isolated from TCM drugs and the FLAG epitope-tagged cDNAs were subcloned into a rAAV plasmid vector. The protein expression was confirmed by Western blot assay. Various cancer cell lines were transfected with the above plasmids and cell growth was monitored both in vitro and in vivo. The best cytotoxic gene was further packaged into rAAV vectors, under the control of a liver cancer-specific promoter. The liver tumor growth was then monitored following intratumor administration of the rAAV vectors.

RESULTSThe expression plasmids, encoding individual potential cytotoxic genes tagged with FLAG epitope, were successfully generated and sequenced. Among these genes, trichosanthin (TCS) gene yielded the most promising results for the inhibition of cancer cell growth in vitro. The over-expressed TCS functioned as a type I ribosome-inactivating protein, followed by inducing apoptosis that is associated with the Bcl-PARP signaling pathway. Furthermore, intratumor injection of rAAV vectors containing the TCS gene significantly inhibited the growth of human hepatocellular carcinoma tumors in a murine xenograft model.

CONCLUSIONOur studies suggest that the use of TCM cytotoxic genes is a useful therapeutic strategy for treating human cancers in general, and liver tumors in particular.

Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; physiology ; Cell Line, Tumor ; DNA, Complementary ; Dependovirus ; Genetic Vectors ; Humans ; Liver Neoplasms ; physiopathology ; Medicine, Chinese Traditional ; methods ; Mice ; Neoplasms ; physiopathology ; Trichosanthin ; genetics ; pharmacology

OBJECTIVETo observe the effects of high expression of recombinant trichosanthin (rTCS) on the cell proliferation and cell cycle of human cervical cancer Caski cells.

METHODEukaryotic expression plasmid pcDNA3.1(-)/6His-TCS was constracted and stably transfected into Caski cells. RT-PCR,Western-blot were used to select the clones with rTCS high-expressing. Using pcDNA3.1(-)-transfected cells as the control, MTT assay and flowcytometry were used to elucidate the effects of rTCS high expression on cell growth and cycle regulation in Caski cells.

RESULTThe Caski cells with stable high expression of rTCS was successfully established, which could inhibit the cell growth (P<0.01) and arrest Caski cells in G1 and G2 phases (P<0.05) obviously.

CONCLUSIONHigh expression of rTCS can inhibit the growth of Caski cervical cancer cells, which might provide a new pathway for the therapy of cervical cancer.

Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Female ; Humans ; Recombinant Proteins ; pharmacology ; Transfection ; methods ; Trichosanthin ; pharmacology ; Uterine Cervical Neoplasms ; pathology

OBJECTIVETo clone the pokeweed anti-viral protein (PAP) gene, to express it in Pichia pastoris, and to study the inhibitory effect of PAP on U251 in vitro.

METHODSThe cDNA sequence encoding PAP was cloned by Real-time PCR from Phytolacca americana. The recombinant PAP was subcloned into the expression vector pPICZaA and expressed in Pichia pastoris GSI15 after methanol induction. SDS-PAGE analysis showed that the expressed PAP existed in the yeast culture supernatant. The drug cytotoxicity to U251 cells was assessed using MTT assay and the obvious apoptotic nuclei of the tumor cells detected using the method of single cell gel electrophoresis.

RESULTSThe full-length PAP gene was cloned. The recombinant expression plasmid pPICZaA-PAP was constructed successfully. SDS-PAGE analysis showed that the relative molecular mass (M) of the recombinant protein was about 35 kDa. The degradation of the genome of the apoptotic cells induced by PAP was detected using the method of single cell gel electrophoresis. PAP possessed very high ability to inhibit the growth of U251. The anti-tumor activities (IC50) to U251 cells of PAP was 81.0 microg/mL.

CONCLUSIONPAP could be a potent anti-tumor candidate for inhibiting the growth of U251 and inducing its apoptosis.

Antineoplastic Agents, Phytogenic ; biosynthesis ; pharmacology ; Apoptosis ; Cell Line, Tumor ; Humans ; Pichia ; metabolism ; Ribosome Inactivating Proteins, Type 1 ; biosynthesis ; pharmacology

OBJECTIVETo investigate the effects of different PAP domains on hepatitis B virus replication.

METHODSThe full length and two truncated PAP mutants were cloned into a eukaryotic expression plasmid, and were transfected into HepG2.2.15 cells using lipofectamine 2000. 3 days after transfection, the medium and cells were collected. HBsAg and HBeAg were measured using ELISA. The titers of HBV DNA were quantified using fluorogenic quantitative PCR (FQ-PCR). HepG2 cells were used to determine the cytotoxicity of the plasmids transfection by MTT assays.

RESULTSThe inhibitory effect on HBV replication of the C-terminal 25 amino acids deleted PAP mutant (pXF3H-PAP14) was not significantly different from that of the full length PAP (pXF3H-PAP12) (Chi-square test = 0.5, 2.0, 0.02, probability value more than 0.05), however, the cytotoxicity of pXF3H-PAP14 was lower than that of pXF3H-PAP12 (Chi-square test = 7.7, probability value less than 0.01). Both N-terminal 69 amino acids deleted mutant and C-terminal 25 amino acids deleted mutant had no cytotoxicity and no antiviral activity.

CONCLUSIONC-terminal 25 amino acid of PAP is related to cytotoxicity but not related to antiviral activity of PAP. N-terminal 69 amino acid of PAP is related to the anti-HBV effect of PAP.

Amino Acid Sequence ; Antiviral Agents ; pharmacology ; Blotting, Western ; DNA, Viral ; drug effects ; metabolism ; Hep G2 Cells ; Hepatitis B Surface Antigens ; metabolism ; Hepatitis B e Antigens ; metabolism ; Hepatitis B virus ; drug effects ; genetics ; physiology ; Humans ; Liposomes ; Plasmids ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Ribosome Inactivating Proteins, Type 1 ; genetics ; metabolism ; pharmacology ; Sequence Deletion ; Transfection ; Virus Replication ; drug effects

The clinical or experimental study proves that Chinese medicine such as Tripteryglum wilfordii, Lignum Sappan, Caulis Sinomenii, Radix Trichosanthis and Herba Artemisiae Annuae have good immunosuppressive activity. Further researches on the immunosuppressive active components from Chinese medicine have been the main direction in recent years. The recent researches on immunosuppressive effect and possible mechanisms for the monomers such as triperine, triptolide, bazilein, potosappanin A, sinomenine, trichosanthin and artemisinin extracted from those Chinese medicine are introduced in this review.
Animals ; Artemisinins ; pharmacology ; therapeutic use ; Diterpenes ; pharmacology ; therapeutic use ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Epoxy Compounds ; pharmacology ; therapeutic use ; Humans ; Immunosuppressive Agents ; pharmacology ; therapeutic use ; Morphinans ; pharmacology ; therapeutic use ; Phenanthrenes ; pharmacology ; therapeutic use ; Plants, Medicinal ; chemistry ; Trichosanthin ; pharmacology ; therapeutic use

OBJECTIVETo construct mature protein curcin gene prokaryotic expression vectors in Escherichia coli and choose the optimal inducing condition of the recombinant strains.

METHODThe gene encoding of curcin was amplified from the genome of Jatropha curcas seeds by PCR and cloned into the expression vectors pQE-30 and pET-32 obtaining recombinant vectors pQE-R and pET-R respectively. The two vectors were transferred into E. coli BL21 (DE3) and the recombinant strains PRM and PRB were attained respectively. PRM and PRB were induced by different revulsants and under different temperature and time.

RESULTThe gene encoding of mature protein curcin was amplified by PCR and the recombinant strains PRM and PRB were obtained.

CONCLUSIONThe results showed that PRB could not produce recombinant protein under such conditions. However, PRM could highly produce recombinant protein induced by 0.5 mmol x L(-1) IPTG at 28 degrees C for 6 h.

Cloning, Molecular ; Escherichia coli ; genetics ; Gene Expression ; drug effects ; Genetic Vectors ; genetics ; metabolism ; Genome, Plant ; genetics ; Jatropha ; genetics ; Ribosome Inactivating Proteins, Type 1 ; biosynthesis ; genetics ; Temperature

OBJECTIVETo prepare the anticolon carcinoma vaccine with rich chaperone peptide and to examine its anticancer immunological efficacy.

METHODSCT26 colon carcinoma cells were cultured in 1 mg/L Trichosanthin 1640 medium at different temperatures to induce the chaperone expression and promote the synthesis of antigen peptides. Groups of these cells treated under the different condition were lysed by the sonic disintegration, and the lysates were centrifuged. The rawpurified proteins were obtained from the supernatants by precipitating with saturated ammonium sulfate and removing the molecules below 50,000 and above 300,000 in molecular weight via dialysis. Furthermore, the proteins with the molecular weights in 70,000, 90,000, 95,000, 110,000 and 170,000 were collected through gel filtration and SDS-PAGE. The purified proteins were analysed by Western blotting, and inspected on the anticancer immunological effects including lymphocyte proliferation and the activities of NK and CTL.

RESULTSMajor of the chaperone peptides of anticancer effects in CT26 cells, including antigen peptides joining with HSP70, HSP90, gp96, HSP110 and HSP170, was satisfactorily extracted and condensed, and rich chaperone peptide composites were successfully obtained. The composites prepared under various condition could all enhance lymphocyte proliferation and the activities of CTL and NK(P<0.01).

CONCLUSIONSThe rich chaperone peptide composites are successfully prepared via dialysis, salt fractionation and gel filtration combined with SDS-PAGE. Both the heat stress and Trichosanthin can increase the composites, which treated by 42 centi-degree heat stress and Trichosanthin are found to possess the strongest anticancer efficacy.

Animals ; Cancer Vaccines ; immunology ; Cells, Cultured ; Heat Stress Disorders ; metabolism ; Heat-Shock Proteins ; metabolism ; Mice ; Mice, Inbred BALB C ; Molecular Chaperones ; immunology ; Trichosanthin ; pharmacology

OBJECTIVETo evaluate the anti-tumor effect of recombinant toxin EGF-TCS against transplanted human hepatocellular carcinoma in nude mice.

METHODSHuman hepatocellular carcinoma BEL-7,402 cells were inoculated subcutaneously in the right axillary region of nude mice, and 6 days later, EGF-TCS was injected intravenously at 100, 50, and 25 microg/kg. The mice were executed on the next day of drug withdrawal and the tumors were weighed and the tumor inhibition rate calculated. Immunohistochemistry was also performed on the tumor tissues to provide clue for the possible pathways of tumor inhibition.

RESULTSEGF-TCS markedly inhibited the tumor growth in nude mice, with a tumor inhibition rate of 71.3%, 60.87% and 45.22% corresponding to EGF-TCS dosage of 100, 50, and 25 microg/kg, respectively. Variance analysis suggested that EGF-Linker-TCS could significantly inhibit the tumor growth in the mice (F=8.712, P=0.006), and immunohistochemistry showed significantly inhibited angiogenesis in the tumors by EGF-TCS. No blood vessels were found in the tumor tissues in high dosage group, and there were also reduced blood vessels in the other two smaller dose groups in comparison with the untreated model group, indicating that EGF-TCS inhibited tumor growth and migration by inhibiting tumor angiogenesis.

CONCLUSIONEGF-TCS can inhibit the growth of solid tumors in nude mice, suggesting the potential value of this preparation in cancer therapy.

Animals ; Antineoplastic Agents ; metabolism ; therapeutic use ; Carcinoma, Hepatocellular ; drug therapy ; Cell Line, Tumor ; Disease Models, Animal ; Epidermal Growth Factor ; Female ; Humans ; Immunotoxins ; genetics ; metabolism ; therapeutic use ; Liver Neoplasms ; drug therapy ; Male ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Random Allocation ; Recombinant Fusion Proteins ; genetics ; metabolism ; therapeutic use ; Trichosanthin ; genetics ; metabolism ; therapeutic use