用超速离心结合密度梯度离心法从蚕蛹中提取家蚕80S核糖体,经尿素变性聚丙烯酰胺凝胶电泳,结果表明家蚕核糖体的RNA同大鼠核糖体RNA在序列长度上有明显差异,家蚕5.8S rRNA高于大鼠5.8S rRNA,而家蚕5S rRNA的序列长度则略低于大鼠。用核...用超速离心结合密度梯度离心法从蚕蛹中提取家蚕80S核糖体,经尿素变性聚丙烯酰胺凝胶电泳,结果表明家蚕核糖体的RNA同大鼠核糖体RNA在序列长度上有明显差异,家蚕5.8S rRNA高于大鼠5.8S rRNA,而家蚕5S rRNA的序列长度则略低于大鼠。用核糖体失活蛋白R ic in分析鉴定家蚕核糖体的Sarc in/R ic in结构域,结果是家蚕Sarc in/R ic in结构域比大鼠Sarc in/R ic in结构域离28S rRNA的3′末端更近。展开更多
BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies, and has a poor prognosis. Despite efforts made in multiple fields, there has been little success in improving the disease-free survival rate of...BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies, and has a poor prognosis. Despite efforts made in multiple fields, there has been little success in improving the disease-free survival rate of patients. This study was undertaken to investigate the effectiveness and feasibility of using intra-tumoral injection of ricin-loaded thermosensitive hydrogel for treatment of pancreatic cancer xenografts, attempting to develop a new treatment for human pancreatic cancer. METHODS: BALB/c-(nu/nu) nude mice were inoculated subcutaneously in the right flank with the human pancreatic cancer cells, SW1990. Fourteen days after inoculation, 32 mice, bearing tumors of volume 1.5-2.0 cm(3), were randomly assigned to one of four groups, and given an intra-tumoral injection of: (1) saline; (2) 23% w/w thermosensitive hydrogel alone; (3) ricin, 10 mu g/kg; or (4) 10 mu g/kg ricin loaded in thermosensitive hydrogel. On day 14 after administration, the tumors were excised to calculate the inhibition rate of tumor growth and perform histopathological examination. Tumor cell apoptosis was detected by flow cytometry, and RT-PCR was performed to evaluate the mRNA expression levels of Bc12 and Bax. RESULTS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel resulted in remarkable control of tumor growth. The tumor became necrotic by day 14 after administration. The histological results clearly confirmed that the tumor cells were lysed. The percentage of apoptotic cells detected by flow cytometry was higher in the ricin hydrogel group than in the other groups. Semi-quantitative RT-PCR revealed that the mRNA expression level of Bc12 was down-regulated whereas Bax was upregulated. CONCLUSIONS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel may provide an effective approach for interstitial chemotherapy in pancreatic cancer. Inducing apoptosis by downregulating Bcl2 expression and upregulating Bax expression may be a key molecular mechanism.展开更多
In this report,purified Ricinus communis agglutinin (RCAl) was employed for analysis ofoligosaccharide molecules in serum of patients with lung cancer or benign diseases.By meansof DEAE-Sephadex A-50 and Sephadex G-10...In this report,purified Ricinus communis agglutinin (RCAl) was employed for analysis ofoligosaccharide molecules in serum of patients with lung cancer or benign diseases.By meansof DEAE-Sephadex A-50 and Sephadex G-100 chromatography,RCAl was purified from the ex-tracts of castor beans.After characterizing its bioactivity by means of red blood coagglutination andpurification by SDS-PAGE,RCAl was coupled with CNBr-activated Sepharose 4B.By RCAl af-finity chromatography,the gtycoproteins containing Galβl-4GlcNAc-linked unit at the nonreducingend of the carbohydrate chain were isolated from the gastric cancer tissue.By means of RCAl andthis glycoproteins labelled with horseradish peroxidase,a competitive binding assay was establishedand employed to detect the level of the oligosaccharides defined by RCAl in serum of pateins withlung cancer or benign diseases and of normal persons.The results suggest that expression of theseoligosaccharide molecules is higher in serum of patient with lung cancer than in serum of patientwith a benign disease of the respiratory system and healthy individuals.The positive rates were60.6%(20/33) in serum of patients with lung cancer,21.4% (6/28) with benign diseases and 4.0%(1/25) of normal persons.It is confirmed that detection of these oligosaccharide molecules in serumcan be helpful in the study and diagnosis of lung cancer.展开更多
The proteins encoded by oncogene were thought to be tumor associated antigen. The protein P110 in MGC803, a human gastric cancer cell line, was purified as immunogen. The IgY to the gastric cancer was extracted from e...The proteins encoded by oncogene were thought to be tumor associated antigen. The protein P110 in MGC803, a human gastric cancer cell line, was purified as immunogen. The IgY to the gastric cancer was extracted from eggs laid by immunized hen. The IgY could react immunohistochemically with gastric cancers. Positive staining rates of PAF were 80% in gastric cancers and markedly higher than in cancers of other organs and normal gastric tissue. The IgY-Ricin A was synthesized by the IgY conjugated with Ricin A- chain. TCID50 of MGC803 treated by the IgY-Ricin A was 0. 01 mg/ml and markedly lower than other cell. These results showed the IgY-Ricin A were able to react with gastric cancers selectively.展开更多
AIM:To evaluate the ability of anti-ricin A-chain antibodies,delivered intracellularly,to protect against ricininduced cytotoxicity in RAW264.7 cells. METHODS:Anti-deglycosylated ricin A-chain antibody and RAC18 anti-...AIM:To evaluate the ability of anti-ricin A-chain antibodies,delivered intracellularly,to protect against ricininduced cytotoxicity in RAW264.7 cells. METHODS:Anti-deglycosylated ricin A-chain antibody and RAC18 anti-ricin A-chain monoclonal antibody were delivered intracellularly by encapsulating in liposomes or via conjugation with the cell-penetrating MTS-transport peptide.RAW264.7 cells were incubatedwith these antibodies either before or after ricin exposure.The changes in cytotoxicity were estimated by MTT assay.Co-localization of internalized antibody and ricin was evaluated by fluorescence microscopy. RESULTS:Internalized antibodies significantly increased cell viability either before or after ricin exposure compared to the unconjugated antibodies.Fluorescence microscopy confirmed the co-localization of internalized antibodies and ricin inside the cells. CONCLUSION:Intracellular delivery of antibodies to neutralize the ricin toxin after cellular uptake supports the potential use of cell-permeable antibodies for postexposure treatment of ricin intoxication.展开更多
A specific cytotoxic agent against gastric cancer was constructed by covalently coupling the ricin A chain to monoclonal artibody, MGb2. MGb2 was modified by SPDP to introduce the 3-(2-pyridylthio) propionyl radical a...A specific cytotoxic agent against gastric cancer was constructed by covalently coupling the ricin A chain to monoclonal artibody, MGb2. MGb2 was modified by SPDP to introduce the 3-(2-pyridylthio) propionyl radical and then treated with a reduced A chain to give a disulfide linked conjugate that retained the original binding specificity of the antibody moiety. The conjugate obtained retained the activity of the antibody and the biological activity of the A chain well.展开更多
AIM: To investigate the therapeutic potential of an RNA ligand (aptamer) specific for the catalytic ricin A-chain (RTA), the protective effects of a 31-nucleo-tide RNA aptamer (31RA), which formed a high affi nity com...AIM: To investigate the therapeutic potential of an RNA ligand (aptamer) specific for the catalytic ricin A-chain (RTA), the protective effects of a 31-nucleo-tide RNA aptamer (31RA), which formed a high affi nity complex with RTA, against ricin-induced toxicity in cellbased luciferase translation and cell cytotoxicity assays were evaluated. METHODS: To test the therapeutic potential of anti-RTA aptamers in Chinese hamster ovary (CHO) AA8 cells stably transfected with a tetracycline regulat-able promoter, ricin ribotoxicity was measured using luciferase and ricin-induced cytotoxicity was ascertained by MTS cell proliferation assay with tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium]. RESULTS: Inhibition of protein synthesis by ricin in CHO AA8 cells resulted in diminished luciferase activity and treatment with polyclonal antibody against degly-cosylated RTA (dgA) neutralized the inhibitory effects of ricin on luciferase activity and protected against ricin-induced cytotoxicity as measured by MTS assay. The 31RA anti-RTA aptamer inhibited the translation of luciferase mRNA in cell-free reticulocyte translation as- say. 31RA aptamer also partially neutralized the inhibitory effects of ricin on luciferase activity and partially protected against ricin-induced cytotoxicity in CHO AA8 cells. CONCLUSION: We have shown that anti-RTA RNA aptamer can protect against ricin ribotoxicity in cellbased luciferase and cell cytotoxicity assays. Hence, RNA aptamer that inhibits RTA enzymatic activity represents a novel class of nucleic acid inhibitor that has the potential to be developed as a therapeutic agent for the treatment of ricin intoxication.展开更多
Ricin is a highly toxic type 2 ribosome-inactivating protein(RIP)which is extracted from the seeds of castor beans.Ricin is considered a potential bioterror agent and no effective antidote for ricin exists so far.In t...Ricin is a highly toxic type 2 ribosome-inactivating protein(RIP)which is extracted from the seeds of castor beans.Ricin is considered a potential bioterror agent and no effective antidote for ricin exists so far.In this study,by structural modification of a retrograde transport blocker Retro-2cyc1,a series of novel compounds were obtained.The primary screen revealed that compound 27 has an improved antiricin activity compare to positive control.In vitro pre-exposure evaluation in Madin-Darby Canine Kidney(MDCK)cells demonstrated that 27 is a powerful anti-ricin compound with an EC50 of 41.05 nmol/L against one LC(lethal concentration,5.56 ng/mL)of ricin.Further studies surprisingly indicated that 27 confers post-exposure activity against ricin intoxication.An in vivo study showed that 1 h post-exposure administration of 27 can improve the survival rate as well as delay the death of ricin-intoxicated mice.A drug combination of 27 with monoclonal antibody mAb4 C13 rescued mice from one LD(lethal dose)ricin challenge and the survival rate of tested animals is 100%.These results represent,for the first time,indication that small molecule retrograde transport blocker confers both in vitro and in vivo post-exposure protection against ricin and therefore provides a promising candidate for the development of anti-ricin medicines.展开更多
Objective: To explore the effect of ricin temperature response gel on breast cancer and its regulatory effect on immune function in rats. Methods: Ricin was purified by chromatography and identified by immunoblottin...Objective: To explore the effect of ricin temperature response gel on breast cancer and its regulatory effect on immune function in rats. Methods: Ricin was purified by chromatography and identified by immunoblotting. The rat subcutaneously transplanted breast cancer model was established. Forty model rats with a tumor diameter of about 3.0 cm were subjected to the study. They were randomized into four groups equally: the model group and three treated groups (blank gel, ricin, ricin-gel) were administered with blank gel, ricin, and ricin temperature response gel via percutaneous intratumor injection, respectively. The tumor was isolated 10 days later for the estimation of tumor inhibition rate (FIR) by weighing, pathologic examination, and detection of tumor apoptosis-associated genes bcl-2 and bax with semiquantitative RT-PCR. Also, peripheral blood was obtained to test T-lymphocyte subsets, the killing function of lymphocytes, and the contents of tumor necrosis factor- oL (TNF- oL ) and interleukin-2 (IL-2). The outcomes were compared between groups. Results: The TIR in the ricin-gel group was 61.8%, with the pathologic examination showing extensive tumor tissue necrosis. Compared with the model group, after ricin temperature response gel treatment, bcl-2 expression was down- regulated, bax expression was up-regulated, CD4+ lymphocytes and CD4+/CD8+ ratio in peripheral blood were increased, the killing function of lymphocytes was enhanced, and the contents of TNF- α and IL-2 were elevated (P〈0.05 or P〈0.01). Conclusion: Intratumor injection of ricin temperature-responsive gel showed significant antitumor effect on breast cancer and could enhance the immune function in the tumor-bearing rat.展开更多
文摘用超速离心结合密度梯度离心法从蚕蛹中提取家蚕80S核糖体,经尿素变性聚丙烯酰胺凝胶电泳,结果表明家蚕核糖体的RNA同大鼠核糖体RNA在序列长度上有明显差异,家蚕5.8S rRNA高于大鼠5.8S rRNA,而家蚕5S rRNA的序列长度则略低于大鼠。用核糖体失活蛋白R ic in分析鉴定家蚕核糖体的Sarc in/R ic in结构域,结果是家蚕Sarc in/R ic in结构域比大鼠Sarc in/R ic in结构域离28S rRNA的3′末端更近。
文摘BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies, and has a poor prognosis. Despite efforts made in multiple fields, there has been little success in improving the disease-free survival rate of patients. This study was undertaken to investigate the effectiveness and feasibility of using intra-tumoral injection of ricin-loaded thermosensitive hydrogel for treatment of pancreatic cancer xenografts, attempting to develop a new treatment for human pancreatic cancer. METHODS: BALB/c-(nu/nu) nude mice were inoculated subcutaneously in the right flank with the human pancreatic cancer cells, SW1990. Fourteen days after inoculation, 32 mice, bearing tumors of volume 1.5-2.0 cm(3), were randomly assigned to one of four groups, and given an intra-tumoral injection of: (1) saline; (2) 23% w/w thermosensitive hydrogel alone; (3) ricin, 10 mu g/kg; or (4) 10 mu g/kg ricin loaded in thermosensitive hydrogel. On day 14 after administration, the tumors were excised to calculate the inhibition rate of tumor growth and perform histopathological examination. Tumor cell apoptosis was detected by flow cytometry, and RT-PCR was performed to evaluate the mRNA expression levels of Bc12 and Bax. RESULTS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel resulted in remarkable control of tumor growth. The tumor became necrotic by day 14 after administration. The histological results clearly confirmed that the tumor cells were lysed. The percentage of apoptotic cells detected by flow cytometry was higher in the ricin hydrogel group than in the other groups. Semi-quantitative RT-PCR revealed that the mRNA expression level of Bc12 was down-regulated whereas Bax was upregulated. CONCLUSIONS: Intra-tumoral injection of ricin-loaded thermosensitive hydrogel may provide an effective approach for interstitial chemotherapy in pancreatic cancer. Inducing apoptosis by downregulating Bcl2 expression and upregulating Bax expression may be a key molecular mechanism.
文摘In this report,purified Ricinus communis agglutinin (RCAl) was employed for analysis ofoligosaccharide molecules in serum of patients with lung cancer or benign diseases.By meansof DEAE-Sephadex A-50 and Sephadex G-100 chromatography,RCAl was purified from the ex-tracts of castor beans.After characterizing its bioactivity by means of red blood coagglutination andpurification by SDS-PAGE,RCAl was coupled with CNBr-activated Sepharose 4B.By RCAl af-finity chromatography,the gtycoproteins containing Galβl-4GlcNAc-linked unit at the nonreducingend of the carbohydrate chain were isolated from the gastric cancer tissue.By means of RCAl andthis glycoproteins labelled with horseradish peroxidase,a competitive binding assay was establishedand employed to detect the level of the oligosaccharides defined by RCAl in serum of pateins withlung cancer or benign diseases and of normal persons.The results suggest that expression of theseoligosaccharide molecules is higher in serum of patient with lung cancer than in serum of patientwith a benign disease of the respiratory system and healthy individuals.The positive rates were60.6%(20/33) in serum of patients with lung cancer,21.4% (6/28) with benign diseases and 4.0%(1/25) of normal persons.It is confirmed that detection of these oligosaccharide molecules in serumcan be helpful in the study and diagnosis of lung cancer.
文摘The proteins encoded by oncogene were thought to be tumor associated antigen. The protein P110 in MGC803, a human gastric cancer cell line, was purified as immunogen. The IgY to the gastric cancer was extracted from eggs laid by immunized hen. The IgY could react immunohistochemically with gastric cancers. Positive staining rates of PAF were 80% in gastric cancers and markedly higher than in cancers of other organs and normal gastric tissue. The IgY-Ricin A was synthesized by the IgY conjugated with Ricin A- chain. TCID50 of MGC803 treated by the IgY-Ricin A was 0. 01 mg/ml and markedly lower than other cell. These results showed the IgY-Ricin A were able to react with gastric cancers selectively.
基金Supported by NIEHS Center Grant ES00260(Tchou-Wong KM)NIAID R21 Grant AI059476(Tchou-Wong KM)from the National Institutes of Health
文摘AIM:To evaluate the ability of anti-ricin A-chain antibodies,delivered intracellularly,to protect against ricininduced cytotoxicity in RAW264.7 cells. METHODS:Anti-deglycosylated ricin A-chain antibody and RAC18 anti-ricin A-chain monoclonal antibody were delivered intracellularly by encapsulating in liposomes or via conjugation with the cell-penetrating MTS-transport peptide.RAW264.7 cells were incubatedwith these antibodies either before or after ricin exposure.The changes in cytotoxicity were estimated by MTT assay.Co-localization of internalized antibody and ricin was evaluated by fluorescence microscopy. RESULTS:Internalized antibodies significantly increased cell viability either before or after ricin exposure compared to the unconjugated antibodies.Fluorescence microscopy confirmed the co-localization of internalized antibodies and ricin inside the cells. CONCLUSION:Intracellular delivery of antibodies to neutralize the ricin toxin after cellular uptake supports the potential use of cell-permeable antibodies for postexposure treatment of ricin intoxication.
文摘A specific cytotoxic agent against gastric cancer was constructed by covalently coupling the ricin A chain to monoclonal artibody, MGb2. MGb2 was modified by SPDP to introduce the 3-(2-pyridylthio) propionyl radical and then treated with a reduced A chain to give a disulfide linked conjugate that retained the original binding specificity of the antibody moiety. The conjugate obtained retained the activity of the antibody and the biological activity of the A chain well.
基金Supported by Grant from the National Institutes of Health (Tchou-Wong), No. ES-000260 and No. AI-059476
文摘AIM: To investigate the therapeutic potential of an RNA ligand (aptamer) specific for the catalytic ricin A-chain (RTA), the protective effects of a 31-nucleo-tide RNA aptamer (31RA), which formed a high affi nity complex with RTA, against ricin-induced toxicity in cellbased luciferase translation and cell cytotoxicity assays were evaluated. METHODS: To test the therapeutic potential of anti-RTA aptamers in Chinese hamster ovary (CHO) AA8 cells stably transfected with a tetracycline regulat-able promoter, ricin ribotoxicity was measured using luciferase and ricin-induced cytotoxicity was ascertained by MTS cell proliferation assay with tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium]. RESULTS: Inhibition of protein synthesis by ricin in CHO AA8 cells resulted in diminished luciferase activity and treatment with polyclonal antibody against degly-cosylated RTA (dgA) neutralized the inhibitory effects of ricin on luciferase activity and protected against ricin-induced cytotoxicity as measured by MTS assay. The 31RA anti-RTA aptamer inhibited the translation of luciferase mRNA in cell-free reticulocyte translation as- say. 31RA aptamer also partially neutralized the inhibitory effects of ricin on luciferase activity and partially protected against ricin-induced cytotoxicity in CHO AA8 cells. CONCLUSION: We have shown that anti-RTA RNA aptamer can protect against ricin ribotoxicity in cellbased luciferase and cell cytotoxicity assays. Hence, RNA aptamer that inhibits RTA enzymatic activity represents a novel class of nucleic acid inhibitor that has the potential to be developed as a therapeutic agent for the treatment of ricin intoxication.
基金the financial supports of the National Science and Technology Major Projects for"Major New Drugs Innovation and Development"(2018ZX09711003-001-001)of China.
文摘Ricin is a highly toxic type 2 ribosome-inactivating protein(RIP)which is extracted from the seeds of castor beans.Ricin is considered a potential bioterror agent and no effective antidote for ricin exists so far.In this study,by structural modification of a retrograde transport blocker Retro-2cyc1,a series of novel compounds were obtained.The primary screen revealed that compound 27 has an improved antiricin activity compare to positive control.In vitro pre-exposure evaluation in Madin-Darby Canine Kidney(MDCK)cells demonstrated that 27 is a powerful anti-ricin compound with an EC50 of 41.05 nmol/L against one LC(lethal concentration,5.56 ng/mL)of ricin.Further studies surprisingly indicated that 27 confers post-exposure activity against ricin intoxication.An in vivo study showed that 1 h post-exposure administration of 27 can improve the survival rate as well as delay the death of ricin-intoxicated mice.A drug combination of 27 with monoclonal antibody mAb4 C13 rescued mice from one LD(lethal dose)ricin challenge and the survival rate of tested animals is 100%.These results represent,for the first time,indication that small molecule retrograde transport blocker confers both in vitro and in vivo post-exposure protection against ricin and therefore provides a promising candidate for the development of anti-ricin medicines.
基金Supported by the Fujian Provincial Funds of Natural Sciences for Creative Items of Youth(No.2009J05066)
文摘Objective: To explore the effect of ricin temperature response gel on breast cancer and its regulatory effect on immune function in rats. Methods: Ricin was purified by chromatography and identified by immunoblotting. The rat subcutaneously transplanted breast cancer model was established. Forty model rats with a tumor diameter of about 3.0 cm were subjected to the study. They were randomized into four groups equally: the model group and three treated groups (blank gel, ricin, ricin-gel) were administered with blank gel, ricin, and ricin temperature response gel via percutaneous intratumor injection, respectively. The tumor was isolated 10 days later for the estimation of tumor inhibition rate (FIR) by weighing, pathologic examination, and detection of tumor apoptosis-associated genes bcl-2 and bax with semiquantitative RT-PCR. Also, peripheral blood was obtained to test T-lymphocyte subsets, the killing function of lymphocytes, and the contents of tumor necrosis factor- oL (TNF- oL ) and interleukin-2 (IL-2). The outcomes were compared between groups. Results: The TIR in the ricin-gel group was 61.8%, with the pathologic examination showing extensive tumor tissue necrosis. Compared with the model group, after ricin temperature response gel treatment, bcl-2 expression was down- regulated, bax expression was up-regulated, CD4+ lymphocytes and CD4+/CD8+ ratio in peripheral blood were increased, the killing function of lymphocytes was enhanced, and the contents of TNF- α and IL-2 were elevated (P〈0.05 or P〈0.01). Conclusion: Intratumor injection of ricin temperature-responsive gel showed significant antitumor effect on breast cancer and could enhance the immune function in the tumor-bearing rat.