Two novel sugar-conjugated 5-fluorocytosine(5-FC)antineoplastic compounds were designed and synthesized to improve the selective drug uptake by targeting the tumor-specific glucose transporter(GLUT).The antitumor acti...Two novel sugar-conjugated 5-fluorocytosine(5-FC)antineoplastic compounds were designed and synthesized to improve the selective drug uptake by targeting the tumor-specific glucose transporter(GLUT).The antitumor activity of these compounds was evaluated in four different human cancer cell lines:A549(human lung cancer cell line),HT29(human colorectal cancer cell line),H460(human lung cancer cell line),and PC3(human prostate cancer cell line).The sugar conjugates exhibited cytotoxicity similar to or higher than 5-FC and 1-hexylcarbamoyl-5-FC in A549,HT29,H460,and PC3.Furthermore,GLUT-mediated transport of the glycoconjugate was investigated with GLUT inhibitor-mediated cytotoxicity analysis in a GLUT-overexpressing HT29 cell line.The cell-killing potency of 5-FC glycoconjugate was found to depend significantly on the GLUT inhibitor,and the cellular uptake of molecules was regulated by GLUT-mediated transport.All the results demonstrate the potential advantages of glycoconjugation for Warburg effect-targeted drug design.展开更多
Background: Adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) play a crucial role in adenosine metabolism in healthy individuals. Adenosine is an inflammatory mediator of asthma. Changes in adenosine metab...Background: Adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) play a crucial role in adenosine metabolism in healthy individuals. Adenosine is an inflammatory mediator of asthma. Changes in adenosine metabolism and role of ADA and 5'-NT in regulating adenosine level in asthmatics and correlation of these changes with severity of asthma are not clearly understood. Methods: In this study, we screened 5217 patients, of which 2416 were diagnosed with asthma. Further, of 2416 asthmatics, only 45 patients who strictly fulfilled the selection criteria were enrolled in the study. The patients were classified into mild, moderate and severe persistent groups;each group consisted of fifteen patients. Fifteen healthy subjects served as controls. Adenosine levels and activities of 5'-NT, total ADA, ADA1 and ADA2 in serum, lymphocytes and erythrocytes were determined. The data were analysed statistically and p vice versa.展开更多
Background：Human sulfatase-1 （Hsulf-l） is an endosulfatase that selectively removes sulfate groups from heparan sulfate proteoglycans （HSPGs）,altering the binding of several growth factors and cytokines to HSPG t...Background：Human sulfatase-1 （Hsulf-l） is an endosulfatase that selectively removes sulfate groups from heparan sulfate proteoglycans （HSPGs）,altering the binding of several growth factors and cytokines to HSPG to regulate cell proliferation,cell motility,and apoptosis.We investigated the role of combined cancer gene therapy with Hsulf-l and cytosine deaminase/5-fluorocytosine （CD/5-FC） suicide gene on a hepatocellular carcinoma （HCC） cell line,HepG2,in vitro and in vivo.Methods：Reverse transcription polymerase chain reaction and immunohistochemistry were used to determine the expression of Hsulf-1 in HCC.Cell apoptosis was observed through flow cytometry instrument and mechanism of Hsulf-1 to enhance the cytotoxicity of 5-FC against HCC was analyzed in HCC by confocal microscopy.We also establish a nude mice model of HCC to address the effect of Hsulf-1 expression on the CD/5-FC suicide gene therapy in vivo.Results：A significant decrease in HepG2 cell proliferation and an increase in HepG2 cell apoptosis were observed when Hsulf-1 expression was combined with the CD/5-FC gene suicide system.A noticeable bystander effect was observed when the Hsulf-1 and CD genes were co-expressed.Intracellular calcium was also increased after HepG2 cells were infected with the Hsulf-1 gene.In vivo studies showed that the suppression of tumor growth was more pronounced in animals treated with the Hsulf-1 plus CD than those treated with either gene therapy alone,and the combined treatment resulted in a significant increase in survival.Conclusions：Hsulf-1 expression combined with the CD/5-FC gene suicide system could be an effective treatment approach for HCC.展开更多
Cytosine Deaminase (CD) from Aspergillus parasiticus was purified and characterized. Time course for maximal CD production (50 μmol/min/mg) was at 72 hrs. The enzyme was purified 387.73 folds with an overall yield of...Cytosine Deaminase (CD) from Aspergillus parasiticus was purified and characterized. Time course for maximal CD production (50 μmol/min/mg) was at 72 hrs. The enzyme was purified 387.73 folds with an overall yield of 13%. The CD had pH optimum of 7.2, a temperature optimum of 40℃ - 45℃, activation of energy (Ea) of 8.4 KJ/mol and a t1/2 of 1.10 hr. A. parasiticus CD stoichiometrically deaminated Cyto-sine and 5-fluorocytosine (5-FC) with the KM values of 0.19mM and 0.30 mM respectively. Studies on the effect of pH on KM and Vmax gave pKa1 of 5.8 and pKa2 of 6.3 with enthalpy of ionization of 43.01 KJ/mole suggesting histidine in the active site. The enzyme was strongly inhibited by Ca2+, Co2+, Zn2+ and Hg2+ and completely inhibited by Cu2+ and Fe2+ at 50 mM. Therefore, A. parasiticus CD can be compared with CDs from other sources that are used in suicide gene therapy.展开更多
AIM： To evaluate bacterial cytosine deaminase （bCD） mutant D314A and 5-fluorocytosine （5-FC） for treatment of colon cancer in a mouse model. METHODS： Recombinant lentivirus vectors that contained wild-type bCD g...AIM： To evaluate bacterial cytosine deaminase （bCD） mutant D314A and 5-fluorocytosine （5-FC） for treatment of colon cancer in a mouse model. METHODS： Recombinant lentivirus vectors that contained wild-type bCD gene （bCDwt）, and bCD mutant D314A gene （bCD-D314A） with green fluorescence protein gene were constructed and used to infect hu- man colon carcinoma LoVo cells, to generate stable transfected cells, LoVo/null, LoVo/bCDwt or LoVo/bCD- D314A. These were injected subcutaneously into Balb/c nude mice to establish xenograft models. Two weeks post-LoVo cell inoculation, PBS or 5-FC （500 mg/kg） was administered by intraperitoneal （i.p.） injection once daily for 14 d. On the day after LoVo cell injection, mice were monitored daily for tumor volume and survival. RESULTS： Sequence analyses confirmed the construction of recombinant lentiviral plasmids that contained bCDwt or bCD-D314A. The lentiviral vector had high elficacy for gene delivery, and RT-PCR showed that bCDwt or bCD-D314A gene was transferred to LoVo cells. Among these treatment groups, gene delivery or 5-FC administration alone had no effect on tumor growth. However, bCDwt/5-FC or bCD-D314A/5-FC treatment inhibited tumor growth and prolonged survival of mice significantly （P 〈 0.05）. Importantly, the tumor volume in the bCD-D314A/5-FC-treated group was lower than that in the bCDwt/5-FC group （P 〈 0.05）, and bCD- D314A plus 5-FC significantly prolonged survival of mice in comparison with bCDwt plus 5-FC （P 〈 0.05）. CONCLUSION： The bCD mutant D314A enhanced significantly antitumor activity in human colon cancer xenograft models, which provides a promising approach for human colon carcinoma therapy.展开更多
基金supported by the National Natural Science Foundation of China (No. 21772144 and No. 21801184)Tianjin Municipal Applied Basic and Key Research Scheme, China (No. 18JCQNIC06400)
文摘Two novel sugar-conjugated 5-fluorocytosine(5-FC)antineoplastic compounds were designed and synthesized to improve the selective drug uptake by targeting the tumor-specific glucose transporter(GLUT).The antitumor activity of these compounds was evaluated in four different human cancer cell lines:A549(human lung cancer cell line),HT29(human colorectal cancer cell line),H460(human lung cancer cell line),and PC3(human prostate cancer cell line).The sugar conjugates exhibited cytotoxicity similar to or higher than 5-FC and 1-hexylcarbamoyl-5-FC in A549,HT29,H460,and PC3.Furthermore,GLUT-mediated transport of the glycoconjugate was investigated with GLUT inhibitor-mediated cytotoxicity analysis in a GLUT-overexpressing HT29 cell line.The cell-killing potency of 5-FC glycoconjugate was found to depend significantly on the GLUT inhibitor,and the cellular uptake of molecules was regulated by GLUT-mediated transport.All the results demonstrate the potential advantages of glycoconjugation for Warburg effect-targeted drug design.
文摘Background: Adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) play a crucial role in adenosine metabolism in healthy individuals. Adenosine is an inflammatory mediator of asthma. Changes in adenosine metabolism and role of ADA and 5'-NT in regulating adenosine level in asthmatics and correlation of these changes with severity of asthma are not clearly understood. Methods: In this study, we screened 5217 patients, of which 2416 were diagnosed with asthma. Further, of 2416 asthmatics, only 45 patients who strictly fulfilled the selection criteria were enrolled in the study. The patients were classified into mild, moderate and severe persistent groups;each group consisted of fifteen patients. Fifteen healthy subjects served as controls. Adenosine levels and activities of 5'-NT, total ADA, ADA1 and ADA2 in serum, lymphocytes and erythrocytes were determined. The data were analysed statistically and p vice versa.
文摘Background：Human sulfatase-1 （Hsulf-l） is an endosulfatase that selectively removes sulfate groups from heparan sulfate proteoglycans （HSPGs）,altering the binding of several growth factors and cytokines to HSPG to regulate cell proliferation,cell motility,and apoptosis.We investigated the role of combined cancer gene therapy with Hsulf-l and cytosine deaminase/5-fluorocytosine （CD/5-FC） suicide gene on a hepatocellular carcinoma （HCC） cell line,HepG2,in vitro and in vivo.Methods：Reverse transcription polymerase chain reaction and immunohistochemistry were used to determine the expression of Hsulf-1 in HCC.Cell apoptosis was observed through flow cytometry instrument and mechanism of Hsulf-1 to enhance the cytotoxicity of 5-FC against HCC was analyzed in HCC by confocal microscopy.We also establish a nude mice model of HCC to address the effect of Hsulf-1 expression on the CD/5-FC suicide gene therapy in vivo.Results：A significant decrease in HepG2 cell proliferation and an increase in HepG2 cell apoptosis were observed when Hsulf-1 expression was combined with the CD/5-FC gene suicide system.A noticeable bystander effect was observed when the Hsulf-1 and CD genes were co-expressed.Intracellular calcium was also increased after HepG2 cells were infected with the Hsulf-1 gene.In vivo studies showed that the suppression of tumor growth was more pronounced in animals treated with the Hsulf-1 plus CD than those treated with either gene therapy alone,and the combined treatment resulted in a significant increase in survival.Conclusions：Hsulf-1 expression combined with the CD/5-FC gene suicide system could be an effective treatment approach for HCC.
文摘Cytosine Deaminase (CD) from Aspergillus parasiticus was purified and characterized. Time course for maximal CD production (50 μmol/min/mg) was at 72 hrs. The enzyme was purified 387.73 folds with an overall yield of 13%. The CD had pH optimum of 7.2, a temperature optimum of 40℃ - 45℃, activation of energy (Ea) of 8.4 KJ/mol and a t1/2 of 1.10 hr. A. parasiticus CD stoichiometrically deaminated Cyto-sine and 5-fluorocytosine (5-FC) with the KM values of 0.19mM and 0.30 mM respectively. Studies on the effect of pH on KM and Vmax gave pKa1 of 5.8 and pKa2 of 6.3 with enthalpy of ionization of 43.01 KJ/mole suggesting histidine in the active site. The enzyme was strongly inhibited by Ca2+, Co2+, Zn2+ and Hg2+ and completely inhibited by Cu2+ and Fe2+ at 50 mM. Therefore, A. parasiticus CD can be compared with CDs from other sources that are used in suicide gene therapy.
文摘AIM： To evaluate bacterial cytosine deaminase （bCD） mutant D314A and 5-fluorocytosine （5-FC） for treatment of colon cancer in a mouse model. METHODS： Recombinant lentivirus vectors that contained wild-type bCD gene （bCDwt）, and bCD mutant D314A gene （bCD-D314A） with green fluorescence protein gene were constructed and used to infect hu- man colon carcinoma LoVo cells, to generate stable transfected cells, LoVo/null, LoVo/bCDwt or LoVo/bCD- D314A. These were injected subcutaneously into Balb/c nude mice to establish xenograft models. Two weeks post-LoVo cell inoculation, PBS or 5-FC （500 mg/kg） was administered by intraperitoneal （i.p.） injection once daily for 14 d. On the day after LoVo cell injection, mice were monitored daily for tumor volume and survival. RESULTS： Sequence analyses confirmed the construction of recombinant lentiviral plasmids that contained bCDwt or bCD-D314A. The lentiviral vector had high elficacy for gene delivery, and RT-PCR showed that bCDwt or bCD-D314A gene was transferred to LoVo cells. Among these treatment groups, gene delivery or 5-FC administration alone had no effect on tumor growth. However, bCDwt/5-FC or bCD-D314A/5-FC treatment inhibited tumor growth and prolonged survival of mice significantly （P 〈 0.05）. Importantly, the tumor volume in the bCD-D314A/5-FC-treated group was lower than that in the bCDwt/5-FC group （P 〈 0.05）, and bCD- D314A plus 5-FC significantly prolonged survival of mice in comparison with bCDwt plus 5-FC （P 〈 0.05）. CONCLUSION： The bCD mutant D314A enhanced significantly antitumor activity in human colon cancer xenograft models, which provides a promising approach for human colon carcinoma therapy.
