BACKGROUND Pancreatic cancer(PC)is one of the most aggressive malignancies characterized by rapid progression and poor prognosis.The involvement of cancer stem cells(CSCs)and Octamer transcription factor 4(OCT4)in PC ...BACKGROUND Pancreatic cancer(PC)is one of the most aggressive malignancies characterized by rapid progression and poor prognosis.The involvement of cancer stem cells(CSCs)and Octamer transcription factor 4(OCT4)in PC pathobiology is being increasingly recognized.AIM To investigate the role of OCT4 in pancreatic CSCs and its effect on PC cell prolif-eration,migration,drug sensitivity,and stemness maintenance.METHODS We analyzed OCT4 and CD133 expression in PC tissues and cell lines.BxPC-3 cells were used to assess the effects of OCT4 modulation on cellular behavior.Proliferation,migration,and stemness of BxPC-3 cells were evaluated,and the PI3K/AKT/mTOR pathway was examined to gain mechanistic insights.RESULTS OCT4 and CD133 were significantly overexpressed in PC tissues.OCT4 mo-dulation altered BxPC-3 cell proliferation,invasion,and stemness,with OCT4 overexpression(OV-OCT4)enhancing these properties and OCT4 interference decreasing them.OV-OCT4 activated the PI3K/AKT/mTOR pathway,which correlated with an increase in PC stem cells(PCSC).CONCLUSION OCT4 plays a crucial role in PCSCs by influencing the aggressiveness and drug resistance of PC cells,thus presenting itself as a potential therapeutic target.展开更多
Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the...Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry（ DESI-MS）, without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer（ m/z 841 ） is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range（pH = 1-5 ）, and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.展开更多
Octameric hemoglobins have been developed by the introduction of surface cysteines in either the alpha or beta chain. Originally designed as a blood substitute, we report here the structure and ligand binding function...Octameric hemoglobins have been developed by the introduction of surface cysteines in either the alpha or beta chain. Originally designed as a blood substitute, we report here the structure and ligand binding function;in addition the interaction with haptoglobin was studied. The recombinant Hbs (rHbs) with mutations alpha Asn78Cys or beta Gly83Cys spontaneously form octamers under conditions where the cysteines are oxidized. Oxygen binding curves and CO kinetic studies indicate a correct allosteric transition of the tetramers within the octamer. Crystallographic studies of the two rHbs show two disulfide bonds per octamer. Reducing agents may provoke dissociation to tetramers, but the octamers are stable when mixed with fresh human plasma, indicating that the reduction by plasma is slower than the oxidation by the dissolved oxygen, consistent with an enhanced stability. The octameric rHbs were also mixed with a solution of haptoglobin (Hp), which binds the dimers of Hb: there was little interaction for incubation times of 15 min;however, on longer timescales a complex was formed. Dynamic light scattering was used to follow the interaction of Hp with the alpha Asn78Cys octamer during 24 hours;a transition from a simple complex of 15 nm to a final size of 60 nm was observed. The results indicate a specific orientation of the αβ dimers may be of importance for the binding to haptoglobin.展开更多
Threonine-substituted serine octamer ions were generated by electrospray ionization（ESI） and investigated by mass spectrometry and infrared photodissociation（IRPD） spectroscopy. IRPD spectra of[L-Ser_7＋ L/D-Thr_1...Threonine-substituted serine octamer ions were generated by electrospray ionization（ESI） and investigated by mass spectrometry and infrared photodissociation（IRPD） spectroscopy. IRPD spectra of[L-Ser_7＋ L/D-Thr_1]H~＋and [L-Ser_6＋ L/D-Thr_2]H~＋were obtained in the range of 2700–3600 cm^（-1）. Chiral differentiation was achieved by comparing their IRPD spectra. The main difference located in the range of 3300–3500 cm^（-1）. And the results indicate the substitution of L-Ser by D-Thr could weaken the intermolecular H-bonds and loosen the original structures of serine octamers.展开更多
Enolase is a conserved cytoplasmic metalloenzyme existing universally in both eukaryotic and prokaryotic cells.The enzyme can also locate on the cell surface and bind to plasminogen,via which contributing to the mucos...Enolase is a conserved cytoplasmic metalloenzyme existing universally in both eukaryotic and prokaryotic cells.The enzyme can also locate on the cell surface and bind to plasminogen,via which contributing to the mucosal surface localization of the bacterial pathogens and assisting the invasion into the host cells.The functions of the eukaryotic enzymes on the cell surface expression(including T cells,B cells,neutrophils,monocytoes,neuronal cells and epithelial cells)are not known.Streptococcus suis serotype 2(S.suis 2,SS2)is an important zoonotic pathogen which has recently caused two large-scale outbreaks in southern China with severe streptococcal toxic shock syndrome(STSS)never seen before in human sufferers.We recently identified the SS2 enolase as an important protective antigen which could protect mice from fatal S.suis 2 infection.In this study,a 2.4-angstrom structure of the SS2 enolase is solved,revealing an octameric arrangement in the crystal.We further demonstrated that the enzyme exists exclusively as an octamer in solution via a sedimentation assay.These results indicate that the octamer is the biological unit of SS2 enolase at least in vitro and most likely in vivo as well.This is,to our knowledge,the first comprehensive characterization of the SS2 enolase octamer both structurally and biophysically,and the second octamer enolase structure in addition to that of Streptococcus pneumoniae.We also investigated the plasminogen binding property of the SS2 enzyme.展开更多
An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is...An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu（II） mixed-ligand coordination polymer, {[Cu2（bpp）2（HzO）2（bpda）2]＇6H2O}n （1） （bpp = 1,3-bis（4-pyridyl）propane and H2bpda = 2,2＇-biphenyldicarboxylic acid）. The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2- are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly （H2O）10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.展开更多
We report a method to tune the second harmonic generation(SHG) frequency of a metallic octamer by employing cylindrical vector beams as the excitation. Our method exploits the ability to spatially match the polarizati...We report a method to tune the second harmonic generation(SHG) frequency of a metallic octamer by employing cylindrical vector beams as the excitation. Our method exploits the ability to spatially match the polarization state of excitations with the fundamental target plasmonic modes, enabling flexible control of the SHG resonant frequency.It is found that SHG of the octamer is enhanced over a broad band(400 nm) by changing the excitation from the linearly polarized Gaussian beam to radially and azimuthally polarized beams. More strikingly, when subjected to an azimuthally polarized beam, the SHG intensity of the octamer becomes 30 times stronger than that for the linearly polarized beam even in the presence of Fano resonance.展开更多
NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R.l. bv. viciae were determined by DNase I footpri...NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R.l. bv. viciae were determined by DNase I footprinting. A series of techniques based on gel retardation were used to analyze the NodD_target DNA interaction, showing that NodD binds to target DNA in isologous octamer.展开更多
Objective:Octamer transcription factor 1(OCT1),a transcription factor that interacts with androgen receptor,is involved in prostate cancer(PCa)progression.The OCT1 target gene,Anillin actin-binding protein(ANLN),is hi...Objective:Octamer transcription factor 1(OCT1),a transcription factor that interacts with androgen receptor,is involved in prostate cancer(PCa)progression.The OCT1 target gene,Anillin actin-binding protein(ANLN),is highly expressed in castration-resistant PCa tissue;however,it remains unclear whether ANLN expression in hormone-sensitive PCa tissue could be used as a predictive biomarker for poor prognosis of patients.We aimed to investigate ANLN expression in PCa tissue obtained via radical prostatectomy and its correlation with clinical parameters.Methods:Immunohistochemical staining for ANLN was performed on 86 PCa specimens,followed by evaluation using immunoreactivity(IR)scores.Prognosis was analyzed by the log-rank test using the Kaplan–Meier method to generate a cancer-specific survival curve.The correlations between ANLN IR and clinical parameters as well as OCT1 IR were analyzed using the Chi-squared test.Results:The median IR score was 0 for ANLN.Accordingly,given the low median IR score,an IR score of≥3 was defined as positive.There were 17(19.8%)ANLN-positive cases,and these cases had a significantly poorer prognosis.Multivariate analysis revealed that the Gleason score,pathological tumor and lymph node stages,and positive ANLN expression were significant predictors of poor prognosis.Notably,patients with both positive ANLN and high OCT1 expression had a significantly decreased overall survival(p=0.001).Conclusion:ANLN,which is a OCT1 target gene especially in castration-resistant PCa,is expressed in a small number of hormone-sensitive PCa cases.Both positive ANLN expression and high OCT1 expression are significantly correlated with poor prognosis for PCa patients.展开更多
The expression of octamer binding factor 4 （Oct4） gene in bladder cancer cell line T24 and its effects on the biological characteristics of the cells were investigated. RT-PCR and Western blot were employed to detec...The expression of octamer binding factor 4 （Oct4） gene in bladder cancer cell line T24 and its effects on the biological characteristics of the cells were investigated. RT-PCR and Western blot were employed to detect the expression of Oct4 in T24 cells. The changes of biological characteristics in T24 cells were analyzed before and after gene-silencing by Boyden chamber and MTT. The results showed that the expression of Oct4 gene was detectable in T24 cells by RT-PCR and Western blot. The expression of Oct4 gene and protein was down-regulated by siRNA, and average number of transwell cells in interference group, negative control group and blank control group was 101.40±54.56, 104.20± 10.03 and 111.00±11.90, respectively. There was significant difference in the proliferation abilit,） of the cells from 48 h, 72 h to 96 h after the interference by siRNA between interference group and negative group or blank control group （P〈0.05）. It was suggested that Oct4 gene was related with proliferation ability of T24 cells, but not with invasive capability.展开更多
基金Supported by Inner Mongolia Natural Science Foundation and the 3rd Affiliated of Inner Medical University,No.2021MS08067.
文摘BACKGROUND Pancreatic cancer(PC)is one of the most aggressive malignancies characterized by rapid progression and poor prognosis.The involvement of cancer stem cells(CSCs)and Octamer transcription factor 4(OCT4)in PC pathobiology is being increasingly recognized.AIM To investigate the role of OCT4 in pancreatic CSCs and its effect on PC cell prolif-eration,migration,drug sensitivity,and stemness maintenance.METHODS We analyzed OCT4 and CD133 expression in PC tissues and cell lines.BxPC-3 cells were used to assess the effects of OCT4 modulation on cellular behavior.Proliferation,migration,and stemness of BxPC-3 cells were evaluated,and the PI3K/AKT/mTOR pathway was examined to gain mechanistic insights.RESULTS OCT4 and CD133 were significantly overexpressed in PC tissues.OCT4 mo-dulation altered BxPC-3 cell proliferation,invasion,and stemness,with OCT4 overexpression(OV-OCT4)enhancing these properties and OCT4 interference decreasing them.OV-OCT4 activated the PI3K/AKT/mTOR pathway,which correlated with an increase in PC stem cells(PCSC).CONCLUSION OCT4 plays a crucial role in PCSCs by influencing the aggressiveness and drug resistance of PC cells,thus presenting itself as a potential therapeutic target.
基金Supported by the National Natural Science Foundation of China(No.20505003).
文摘Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry（ DESI-MS）, without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer（ m/z 841 ） is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range（pH = 1-5 ）, and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.
文摘Octameric hemoglobins have been developed by the introduction of surface cysteines in either the alpha or beta chain. Originally designed as a blood substitute, we report here the structure and ligand binding function;in addition the interaction with haptoglobin was studied. The recombinant Hbs (rHbs) with mutations alpha Asn78Cys or beta Gly83Cys spontaneously form octamers under conditions where the cysteines are oxidized. Oxygen binding curves and CO kinetic studies indicate a correct allosteric transition of the tetramers within the octamer. Crystallographic studies of the two rHbs show two disulfide bonds per octamer. Reducing agents may provoke dissociation to tetramers, but the octamers are stable when mixed with fresh human plasma, indicating that the reduction by plasma is slower than the oxidation by the dissolved oxygen, consistent with an enhanced stability. The octameric rHbs were also mixed with a solution of haptoglobin (Hp), which binds the dimers of Hb: there was little interaction for incubation times of 15 min;however, on longer timescales a complex was formed. Dynamic light scattering was used to follow the interaction of Hp with the alpha Asn78Cys octamer during 24 hours;a transition from a simple complex of 15 nm to a final size of 60 nm was observed. The results indicate a specific orientation of the αβ dimers may be of importance for the binding to haptoglobin.
基金Financial support from the National Natural Science Foundation of China(No.21475065)
文摘Threonine-substituted serine octamer ions were generated by electrospray ionization（ESI） and investigated by mass spectrometry and infrared photodissociation（IRPD） spectroscopy. IRPD spectra of[L-Ser_7＋ L/D-Thr_1]H~＋and [L-Ser_6＋ L/D-Thr_2]H~＋were obtained in the range of 2700–3600 cm^（-1）. Chiral differentiation was achieved by comparing their IRPD spectra. The main difference located in the range of 3300–3500 cm^（-1）. And the results indicate the substitution of L-Ser by D-Thr could weaken the intermolecular H-bonds and loosen the original structures of serine octamers.
基金supported by National Natural Science Foundation of China(NSFC)a leading principal investigator of the NSFC Innovative Research Group(Grant No.81021003).
文摘Enolase is a conserved cytoplasmic metalloenzyme existing universally in both eukaryotic and prokaryotic cells.The enzyme can also locate on the cell surface and bind to plasminogen,via which contributing to the mucosal surface localization of the bacterial pathogens and assisting the invasion into the host cells.The functions of the eukaryotic enzymes on the cell surface expression(including T cells,B cells,neutrophils,monocytoes,neuronal cells and epithelial cells)are not known.Streptococcus suis serotype 2(S.suis 2,SS2)is an important zoonotic pathogen which has recently caused two large-scale outbreaks in southern China with severe streptococcal toxic shock syndrome(STSS)never seen before in human sufferers.We recently identified the SS2 enolase as an important protective antigen which could protect mice from fatal S.suis 2 infection.In this study,a 2.4-angstrom structure of the SS2 enolase is solved,revealing an octameric arrangement in the crystal.We further demonstrated that the enzyme exists exclusively as an octamer in solution via a sedimentation assay.These results indicate that the octamer is the biological unit of SS2 enolase at least in vitro and most likely in vivo as well.This is,to our knowledge,the first comprehensive characterization of the SS2 enolase octamer both structurally and biophysically,and the second octamer enolase structure in addition to that of Streptococcus pneumoniae.We also investigated the plasminogen binding property of the SS2 enzyme.
基金supported by the National Natural Science Foundation of China (50971063,21053001)the Natural Science Foundation of Fujian Province (2011J01047,2003F006,2010J01042)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of Chinathe Startup Package Funding of Huaqiao University (10BS210 and 11BS102)
文摘An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu（II） mixed-ligand coordination polymer, {[Cu2（bpp）2（HzO）2（bpda）2]＇6H2O}n （1） （bpp = 1,3-bis（4-pyridyl）propane and H2bpda = 2,2＇-biphenyldicarboxylic acid）. The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2- are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly （H2O）10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.
基金National Key R&D Program of China(2017YFA0303800)National Natural Science Foundation of China(NSFC)(11634010,51777168,61377035,61675170,61675171,61701303)+4 种基金Australian Research Council(ARC)(DP140100883)Natural Science Basic Research Plan in Shaanxi Province,China(2017JM6022)Fundamental Research Funds for the Central Universities,China(3102017zy017)Natural Science Foundation of Shanghai,China(17ZR1414300)Shanghai Pujiang Program,China(17PJ1404100)
文摘We report a method to tune the second harmonic generation(SHG) frequency of a metallic octamer by employing cylindrical vector beams as the excitation. Our method exploits the ability to spatially match the polarization state of excitations with the fundamental target plasmonic modes, enabling flexible control of the SHG resonant frequency.It is found that SHG of the octamer is enhanced over a broad band(400 nm) by changing the excitation from the linearly polarized Gaussian beam to radially and azimuthally polarized beams. More strikingly, when subjected to an azimuthally polarized beam, the SHG intensity of the octamer becomes 30 times stronger than that for the linearly polarized beam even in the presence of Fano resonance.
文摘NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R.l. bv. viciae were determined by DNase I footprinting. A series of techniques based on gel retardation were used to analyze the NodD_target DNA interaction, showing that NodD binds to target DNA in isologous octamer.
基金supported by funding from Takeda Science Foundation,and JSPS KAKENHI(grant numbers JP19H03793 to Obinata D,JP20K07350 to Takayama K,JP19K09740 to Takahashi S,JP20K07875 to Hara M,and JP20K21667 and JP21H04829 to Inoue S).
文摘Objective:Octamer transcription factor 1(OCT1),a transcription factor that interacts with androgen receptor,is involved in prostate cancer(PCa)progression.The OCT1 target gene,Anillin actin-binding protein(ANLN),is highly expressed in castration-resistant PCa tissue;however,it remains unclear whether ANLN expression in hormone-sensitive PCa tissue could be used as a predictive biomarker for poor prognosis of patients.We aimed to investigate ANLN expression in PCa tissue obtained via radical prostatectomy and its correlation with clinical parameters.Methods:Immunohistochemical staining for ANLN was performed on 86 PCa specimens,followed by evaluation using immunoreactivity(IR)scores.Prognosis was analyzed by the log-rank test using the Kaplan–Meier method to generate a cancer-specific survival curve.The correlations between ANLN IR and clinical parameters as well as OCT1 IR were analyzed using the Chi-squared test.Results:The median IR score was 0 for ANLN.Accordingly,given the low median IR score,an IR score of≥3 was defined as positive.There were 17(19.8%)ANLN-positive cases,and these cases had a significantly poorer prognosis.Multivariate analysis revealed that the Gleason score,pathological tumor and lymph node stages,and positive ANLN expression were significant predictors of poor prognosis.Notably,patients with both positive ANLN and high OCT1 expression had a significantly decreased overall survival(p=0.001).Conclusion:ANLN,which is a OCT1 target gene especially in castration-resistant PCa,is expressed in a small number of hormone-sensitive PCa cases.Both positive ANLN expression and high OCT1 expression are significantly correlated with poor prognosis for PCa patients.
文摘The expression of octamer binding factor 4 （Oct4） gene in bladder cancer cell line T24 and its effects on the biological characteristics of the cells were investigated. RT-PCR and Western blot were employed to detect the expression of Oct4 in T24 cells. The changes of biological characteristics in T24 cells were analyzed before and after gene-silencing by Boyden chamber and MTT. The results showed that the expression of Oct4 gene was detectable in T24 cells by RT-PCR and Western blot. The expression of Oct4 gene and protein was down-regulated by siRNA, and average number of transwell cells in interference group, negative control group and blank control group was 101.40±54.56, 104.20± 10.03 and 111.00±11.90, respectively. There was significant difference in the proliferation abilit,） of the cells from 48 h, 72 h to 96 h after the interference by siRNA between interference group and negative group or blank control group （P〈0.05）. It was suggested that Oct4 gene was related with proliferation ability of T24 cells, but not with invasive capability.
