AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal c...AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P 【 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.展开更多
The properties and characteristics of the polymer used for the preparation of matrix drug delivery systems considerably influence their performance and the extent of drug release and its mechanism. The objective of th...The properties and characteristics of the polymer used for the preparation of matrix drug delivery systems considerably influence their performance and the extent of drug release and its mechanism. The objective of this research was to examine the dimensional changes, and gel evolution of polymer matrices consisting of three different polymers Polyox, sodium alginate (hydrophilic) and Ethocel (hydrophobic), using an image analysis method. Furthermore to explore how these changes influence the release rate of a soluble drug namely, venlafaxine. All tablets displayed marked dimensional expansion and gel growth particularly those consisting of two hydrophilic polymers Polyox/sodium alginate (POL/SA/V) compared to those consisting of the hydrophilic/hydrophobic Polyox/Ethocel (POL/ET/V). Similarly the thickness of the gel layer in POL/SA/V matrices increased considerably with time up to 8 hours. In general our findings show that the POL/SA/V matrices, due to their thicker gel layer produced a more effective barrier which results in a more pronounced sustained release delivery. This accounts for the slower and smaller overall drug release observed with the POL/SA/V matrices compared to those containing POL/ET/V and indicates that the formation of a thick and durable gel barrier is a characteristic necessary for the preparation of sustained drug release systems. Moreover the solubility of venlafaxine in combination with the polymer’s properties appears to play an important role on the extent of drug release and the release mechanism. Overall the polymer mixtures examined comprise a useful and promising combination of materials for the development and manufacture of sustained release preparations based on these polymers.展开更多
Objective To provide suggestions for further improvement of China’s drug post-approval change management system.Methods The current legal and regulatory requirements of post-approval change management systems of drug...Objective To provide suggestions for further improvement of China’s drug post-approval change management system.Methods The current legal and regulatory requirements of post-approval change management systems of drugs in USA,EU and China were compared and analyzed.Results and Conclusion The post-approval change management of drugs is an important part of the whole life-cycle management of drugs.However,there are still some problems in China’s current post-approval change management systems.According to the model and requirements of the post-approval change management systems of the USA and EU,this paper proposes the following suggestions for the improvement of China’s post-approval change management system.Firstly,electronic files for licensed products should be created.Then,regulatory standards at the national level must be unified.Lastly,the concept of product life cycle management should be implemented.展开更多
Drug development in oncology is undergoing a substantial shift nowadays. The drivers for this are multi-factorial. On the one side, drug development is performed more rationally than ever, profiting from the scientifi...Drug development in oncology is undergoing a substantial shift nowadays. The drivers for this are multi-factorial. On the one side, drug development is performed more rationally than ever, profiting from the scientific advances in molecular biology in general and the elucidation of the various ＂omes＂ from genome to metabolome in particular.展开更多
In the field of biomedicine, stimuli-responsive drug delivery systems(DDSs) have become increasingly popular due to their site-specific release ability in response to a certain physiological stimulus, which may result...In the field of biomedicine, stimuli-responsive drug delivery systems(DDSs) have become increasingly popular due to their site-specific release ability in response to a certain physiological stimulus, which may result in both enhanced treatment outcome and reduced side effects. Reactive oxygen species(ROS) are the unavoidable consequence of cell oxidative metabolism. ROS play a crucial part in regulating biological and physiological processes,whereas excessive intracellular ROS usually lead to the oxidation stress which has implications in several typical diseases such as cancer, inflammation and atherosclerosis. Therefore,ROS-responsive DDSs have elicited widespread popularity for their promising applications in a series of biomedical research because the payload is only released in targeted cells or tissues that overproduce ROS. According to the design of ROS-responsive DDSs, the main release mechanisms of therapeutic agents can be ascribed to ROS-induced carrier solubility change, ROS-induced carrier cleavage or ROS-induced prodrug linker cleavage. This review summarized the latest development and novel design of ROS-responsive DDSs and discussed their design concepts and the applications in the biomedical field.展开更多
Isothermal titration calorimetry (ITC) was applied to investigate the interaction of drugs with liposomes. Two types of titration are possible. One type is when the liposome suspension in the cell is titrated by aliqu...Isothermal titration calorimetry (ITC) was applied to investigate the interaction of drugs with liposomes. Two types of titration are possible. One type is when the liposome suspension in the cell is titrated by aliquots of drug solution, and the other is when the drug and liposome solutions take the opposite roles. In this paper, we employed the latter type because the disturbance of liposomes may be minimal in this titration type. We derived an equation in which the accumulated heat-flow is expressed as a function of the added lipid concentration. In the derivation, the uniform binding model was used although there may be various binding sites. This equation contains a parameter n, the number of binding sites per lipid molecule. In addition, we derive the relation between the dissociation constant (Kd), partition coefficient (Pm) and n. Binding parameters such as Kd, n, the Gibbs energy change, enthalpy change and entropy change were estimated for ANS (1-anilino-8-naphtarenesulfonate), TPB (tetraphenylborate), amlodipine, nifedipine, amitriptyline, nortriptyline, imipramine, desipramine, propranolol, chlorpromazine, promethazine, miconazole, indomethacin, diclofenac and diflunisal. For some drugs, the enthalpy change was the major binding affinity instead of the classical hydrophobic interaction in which entropy takes the essential role. We proved an approximate rule that for drugs with smaller n (the number of binding sites per lipid molecule), the entropy change contributes more than the enthalpy change.展开更多
Drug regulation is the most important policy to ensure drug safety.In this article,we analyzed institutional changes and problems in China＇s drug regulation.In addition,suggestions were provided to enhance the capaci...Drug regulation is the most important policy to ensure drug safety.In this article,we analyzed institutional changes and problems in China＇s drug regulation.In addition,suggestions were provided to enhance the capacity of drug regulation,including a clearer functional positioning for drug regulation,increased resource inputs in drug regulation at central level,a more rational allocation of vertical drug regulatory functions,and an improved supervision mechanism for regulatory departments.展开更多
基金Project supported by the National Natural Science Foundation of China,No.39570806National Excel1ent Youth Scientific Foundation,No.3952020.
文摘AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P 【 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.
文摘The properties and characteristics of the polymer used for the preparation of matrix drug delivery systems considerably influence their performance and the extent of drug release and its mechanism. The objective of this research was to examine the dimensional changes, and gel evolution of polymer matrices consisting of three different polymers Polyox, sodium alginate (hydrophilic) and Ethocel (hydrophobic), using an image analysis method. Furthermore to explore how these changes influence the release rate of a soluble drug namely, venlafaxine. All tablets displayed marked dimensional expansion and gel growth particularly those consisting of two hydrophilic polymers Polyox/sodium alginate (POL/SA/V) compared to those consisting of the hydrophilic/hydrophobic Polyox/Ethocel (POL/ET/V). Similarly the thickness of the gel layer in POL/SA/V matrices increased considerably with time up to 8 hours. In general our findings show that the POL/SA/V matrices, due to their thicker gel layer produced a more effective barrier which results in a more pronounced sustained release delivery. This accounts for the slower and smaller overall drug release observed with the POL/SA/V matrices compared to those containing POL/ET/V and indicates that the formation of a thick and durable gel barrier is a characteristic necessary for the preparation of sustained drug release systems. Moreover the solubility of venlafaxine in combination with the polymer’s properties appears to play an important role on the extent of drug release and the release mechanism. Overall the polymer mixtures examined comprise a useful and promising combination of materials for the development and manufacture of sustained release preparations based on these polymers.
文摘Objective To provide suggestions for further improvement of China’s drug post-approval change management system.Methods The current legal and regulatory requirements of post-approval change management systems of drugs in USA,EU and China were compared and analyzed.Results and Conclusion The post-approval change management of drugs is an important part of the whole life-cycle management of drugs.However,there are still some problems in China’s current post-approval change management systems.According to the model and requirements of the post-approval change management systems of the USA and EU,this paper proposes the following suggestions for the improvement of China’s post-approval change management system.Firstly,electronic files for licensed products should be created.Then,regulatory standards at the national level must be unified.Lastly,the concept of product life cycle management should be implemented.
文摘Drug development in oncology is undergoing a substantial shift nowadays. The drivers for this are multi-factorial. On the one side, drug development is performed more rationally than ever, profiting from the scientific advances in molecular biology in general and the elucidation of the various ＂omes＂ from genome to metabolome in particular.
基金financially supported by Program for Liaoning Innovative Research Team in University (LT2014022)
文摘In the field of biomedicine, stimuli-responsive drug delivery systems(DDSs) have become increasingly popular due to their site-specific release ability in response to a certain physiological stimulus, which may result in both enhanced treatment outcome and reduced side effects. Reactive oxygen species(ROS) are the unavoidable consequence of cell oxidative metabolism. ROS play a crucial part in regulating biological and physiological processes,whereas excessive intracellular ROS usually lead to the oxidation stress which has implications in several typical diseases such as cancer, inflammation and atherosclerosis. Therefore,ROS-responsive DDSs have elicited widespread popularity for their promising applications in a series of biomedical research because the payload is only released in targeted cells or tissues that overproduce ROS. According to the design of ROS-responsive DDSs, the main release mechanisms of therapeutic agents can be ascribed to ROS-induced carrier solubility change, ROS-induced carrier cleavage or ROS-induced prodrug linker cleavage. This review summarized the latest development and novel design of ROS-responsive DDSs and discussed their design concepts and the applications in the biomedical field.
文摘Isothermal titration calorimetry (ITC) was applied to investigate the interaction of drugs with liposomes. Two types of titration are possible. One type is when the liposome suspension in the cell is titrated by aliquots of drug solution, and the other is when the drug and liposome solutions take the opposite roles. In this paper, we employed the latter type because the disturbance of liposomes may be minimal in this titration type. We derived an equation in which the accumulated heat-flow is expressed as a function of the added lipid concentration. In the derivation, the uniform binding model was used although there may be various binding sites. This equation contains a parameter n, the number of binding sites per lipid molecule. In addition, we derive the relation between the dissociation constant (Kd), partition coefficient (Pm) and n. Binding parameters such as Kd, n, the Gibbs energy change, enthalpy change and entropy change were estimated for ANS (1-anilino-8-naphtarenesulfonate), TPB (tetraphenylborate), amlodipine, nifedipine, amitriptyline, nortriptyline, imipramine, desipramine, propranolol, chlorpromazine, promethazine, miconazole, indomethacin, diclofenac and diflunisal. For some drugs, the enthalpy change was the major binding affinity instead of the classical hydrophobic interaction in which entropy takes the essential role. We proved an approximate rule that for drugs with smaller n (the number of binding sites per lipid molecule), the entropy change contributes more than the enthalpy change.
文摘Drug regulation is the most important policy to ensure drug safety.In this article,we analyzed institutional changes and problems in China＇s drug regulation.In addition,suggestions were provided to enhance the capacity of drug regulation,including a clearer functional positioning for drug regulation,increased resource inputs in drug regulation at central level,a more rational allocation of vertical drug regulatory functions,and an improved supervision mechanism for regulatory departments.
