Drug resistance is one of the most intractable issues in targeted therapy for cancer diseases.It has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory ca...Drug resistance is one of the most intractable issues in targeted therapy for cancer diseases.It has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory cancer cell populations.Focusing on how cancer cells develop resistance during the encounter with targeted drugs and the immune system,we propose a mathematical model for studying the dynamics of drug resistance in a conjoint heterogeneous tumor-immune setting.We analyze the local geometric properties of the equilibria of the model.Numerical simulations show that the selectively targeted removal of sensitive cancer cells may cause the initially heterogeneous population to become a more resistant population.Moreover,the decline of immune recruitment is a stronger determinant of cancer escape from immune surveillance or targeted therapy than the decay in immune predation strength.Sensitivity analysis of model parameters provides insight into the roles of the immune system combined with targeted therapy in determining treatment outcomes.展开更多
Objective To identify nivolumab resistance-related genes in patients with head and neck squamous cell carcinoma(HNSCC)using single-cell and bulk RNA-sequencing data.Methods The single-cell and bulk RNA-sequencing data...Objective To identify nivolumab resistance-related genes in patients with head and neck squamous cell carcinoma(HNSCC)using single-cell and bulk RNA-sequencing data.Methods The single-cell and bulk RNA-sequencing data downloaded from the Gene Expression Omnibus database were analyzed to screen out differentially expressed genes(DEGs)between nivolumab resistant and nivolumab sensitive patients using R software.The Least Absolute Shrinkage Selection Operator(LASSO)regression and Recursive Feature Elimination(RFE)algorithm were performed to identify key genes associated with nivolumab resistance.Functional enrichment of DEGs was analyzed with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses.The relationships of key genes with immune cell infiltration,differentation trajectory,dynamic gene expression profiles,and ligand-receptor interaction were explored.Results We found 83 DEGs.They were mainly enriched in T-cell differentiation,PD-1 and PD-L1 checkpoint,and T-cell receptor pathways.Among six key genes identified using machine learning algorithms,only PPP1R14A gene was differentially expressed between the nivolumab resistant and nivolumab sensitive groups both before and after immunotherapy(P<0.05).The high PPP1R14A gene expression group had lower immune score(P<0.01),higher expression of immunosuppressive factors(such as PDCD1,CTLA4,and PDCD1LG2)(r>0,P<0.05),lower differentiation of infiltrated immune cells(P<0.05),and a higher degree of interaction between HLA and CD4(P<0.05).Conclusions PPP1R14A gene is closely associated with resistance to nivolumab in HNSCC patients.Therefore,PPP1R14A may be a target to ameliorate nivolumab resistance of HNSCC patients.展开更多
Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicin...Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle.However,the patterns of transcript isoform expression in the cell cycle are unclear.Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies,but none of them have been designed or evaluated at the alternative splicing transcript level.The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown,and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare.Methods:To explore alternative splicing patterns during cell cycle progression,we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines,using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples,and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle.Genomics of Drug Sensitivity in Cancer(GDSC)drug sensitivity datasets and Cancer Cell Line Encyclopedia(CCLE)transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity.We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients.Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6(CDK4/6)inhibitors.Finally,alternative splicing transcripts associated with mitotic(M)phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis.Results:We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells.The results of the cell cycle assessment showed that 43,326,41,578 and 29,244 transcripts were found to be periodically expressed in HeLa,HCT116 and MDA-MB-231 cells,respectively,among which 1280 transcripts showed this expression pattern in all three cancer cell lines.Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes.Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904.The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts.Combined with the cell cycle-related drug screening,the results also showed that a set of periodic transcripts,for example,ENST00000314392(a dolichylphosphate mannosyltransferase polypeptide 2 isoform transcript),was more associated with drug sensitivity than the levels of their corresponding gene transcripts.Conclusions:In summary,we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity,providing novel insights into alternative splicing-related drug development and evaluation.展开更多
To study the characteristics of drug-resistant genetic mutation of rpoB on coal workers＇ pneumoconiosis complicated with L-form of Mycobacterium tuberculosis. Methods： A total of 42 clinical isolated strains of Myco...To study the characteristics of drug-resistant genetic mutation of rpoB on coal workers＇ pneumoconiosis complicated with L-form of Mycobacterium tuberculosis. Methods： A total of 42 clinical isolated strains of Mycobacterium tuberculosis L-forms were collected, including 31 drug-resistant strains. Their genomes DNA were extracted, the target genes were amplified by PCR, and the hot regions in the rpoB gene were analyzed by automated DNA sequenator. Results： No mutation of rpoB gene was identified in 11 rifampicin-sensitive strains while conformation changes were found in 31 rifampicin-resistant strains. The mutation rate was 93.55% （29/31） in resistant strains, mainly concentrated in codon 531 （51.6%, 16/31） and 526 （32.26%, 10/31）. Base substitutions happened, including 27 unit point mutation and 2 two point mutation. The mutation of codon 516 that new found wasn＇t reported by internal and overseas scholars. Conclusion： The substitution of highly conserved amino acids encoded by rpoB gene results in the molecular mechanism responsible for rifampicin resistance in Mycobacterium tuberculosis L-forms. It also proves that rpoB gene is diversiform.展开更多
Objective：To investigate the expression of CXCR4 on HL-60 cell line and the proliferation, apoptosis of HL-60 cell line cocultured with bone marrow stromal cells, so as to assess the possibility of 12G5, an anti-CXCR...Objective：To investigate the expression of CXCR4 on HL-60 cell line and the proliferation, apoptosis of HL-60 cell line cocultured with bone marrow stromal cells, so as to assess the possibility of 12G5, an anti-CXCR4 monoclonal antibody, in eradicating the minimal residual disease. Methods：The activity of SDF-1 was inhibited by 10 μg/ml 12G5. After treatment with 12G5, the status of adhesion was observed, and the adhesion rates, apoptosis and cell cycles were detected after 24 h of treatment. Cell growth rates were measured by trypan blue exclusion. Cell growth curve was plotted, and the expression of PCNA and apoptosis related protein including PCNA, Bcl-2 and Fas were detected with immunohistochemical technique. Results：（1） There was middling degree expression of CXCR4 on HL-B0 membrane. From 0 h to 6 h, as the time of 12G5 incubation along, the expression of CXCR4 decreased gradually. （2） After treatment for 24 h, the adhesion rates in the experiment group and the control were （39.4±7.9）% and （51.4±5.9）%, respectively. （3）After treatment for 24 h, the percentage of HL-60 cells in G0/G1 phase were （55.21±4.9）%, and that in S phase and G2/M phase were （30.40±4.1）% and （14.39± 5.2）%, respectively, with the corresponding proportions being （44. 67±2.2）%, （45.30±3.7）%, and （10. 03±2.6）% in the control. （4） The percentage of apoptotic HL-60 cells was （8.95±1.7）% in the experiment group, compared to （3. 97±2. 4）% in the control. （5）The survival rates of HL-60 cells decreased markedly at 48 h to 96 h, and the proliferation slowed down at this time duration. （6）The expression of PCNA and Bcl-2 down-regulated significantly, but the Fas protein expression was up-regulated. Conclusion：12G5 could inhibit the capability of adhesion and proliferation of HL-60 cells and it can induce more cells to enter G0/G1 phase and promote apoptosis. It may be helpful by inhibiting the bioactivity of SDF-1 with 12G5 in the therapy of marrow residual disease.展开更多
P-glycoprotein plays an important role in highly drug resistant cells. But its high expression cannot be acheived by chemotherapy. In order to study the effect of P-glycoprotein on clinical tumors, we established a lo...P-glycoprotein plays an important role in highly drug resistant cells. But its high expression cannot be acheived by chemotherapy. In order to study the effect of P-glycoprotein on clinical tumors, we established a low ADM resistant colon cancer cell line HR/ADM and determined the amplification and expression of mdr-1 gene. The GLC/ADM showed a resistant pattern similar to classical MDR and the transcription of mdr-1 gene determined by RT-PCR increased. The immunocytochemical analysis showed strong positive staining with monoclonal antibody. The gene amplification of mdr-1 was clearly demonstrated by southernblot. Our results suggested that moderate expression of P-glycoprotein might be enough for a high resistantpattern.展开更多
Objective： To study the effect of the extract of Prunella vulgaris L. on multiple drugs resistant bacillus tuberculosis （MDR-TB）. Methods： Experimental animal model in rats was induced by MDR-TB. Normal group mode...Objective： To study the effect of the extract of Prunella vulgaris L. on multiple drugs resistant bacillus tuberculosis （MDR-TB）. Methods： Experimental animal model in rats was induced by MDR-TB. Normal group model group and Prunella vulgaris L. group were set up. The contents of IFN-7, IL-4, IL-10 and IL-12 were examined by ELISA. Their genome mRNAs were extracted, the target genes were amplified by PCR. RT-PCR was used to detect the mRNA levels of them. Results： The content of IFN-q, of the extract of Prunella vulgaris L. group was 1.98±0.67 pg/ml, IL-4 was 6.47±1.46 pg/ml, IL-10 was 12.13±3.43 pg/ml and IL-12 was 3.02±0.86 pg/ml. Compared with the model group, Prunella vulgaris L. group was notable difference in serum IFN-γ, IL-12 and IL-10 （P〈0.05）. The mRNA levels of IFN-γ, IL-12 increased and IL-10 decreased obviously, the differences were quite significant （P〈0.05）, but IL-4 had no obvious change. Conclusion： The extract of Prunella vulgaris L. can enhance the cellar immunological function in rats from up-regulation of the level of genetic transcription, accordingly provide the theory basis of healing of tuberculosis with it.展开更多
Background The epidemiological characteristics of drug-resistant tuberculosis （DR-TB） is fundamental to improving the prevention and control of DR-TB. Mutations in katG315 is thought to be the most predictive molecu...Background The epidemiological characteristics of drug-resistant tuberculosis （DR-TB） is fundamental to improving the prevention and control of DR-TB. Mutations in katG315 is thought to be the most predictive molecule markers for Isoniazid （INH） resistance in Mycobacterium tuberculosis （MTB）. However, mutations to these genes have not been thoroughly studied in China, and epidemiological evidence of their expression levels are especially lacking in the southwest of China, which has a high TB burden within the population. Methods MTB isolates were obtained from patients with active pulmonary tuberculosis at the TB dispensary and Chest hospital in Chongqing city between June 2003 and June 2006. Proportion methods were used to test the sensitivity to INH, RFP, SM and EMB of cultured MTB. A total of 100 MTB isolates were also randomly selected for analysis of the molecular mutation spectrum of katG by DNA sequencing. Results Totally 1 089 MTB isolates that completed positive sputum cultures and evaluated for their sensitivity to the four first-line drugs among 2 777 patients with TB. The prevalence of DR-TB and multi-drug resistant tuberculosis （MDR-TB） were 27.7% （302/1 089） and 7.3% （79/1 089）, respectively. The resistance to anti-TB drugs was found to be highest for SM （16.3%） and INH （14.0%）. There was also a significant increase in the prevalence of resistance to RFP and EMB （P〈0.01）, and an increase in MDR-TB between June 2003 and June 2004 and between July 2005 and June 2006. The total mutation rate of katG315 was 75＂5% （37/49） in INH-resistant MTB, and mutation sites included $315T, $315N and $315I with mutation rates of 81.1% （30/37）, 13.5% （5/37） and 5.4% （2/37）, respectively No katG315 mutants were found in any of the 48 INH-sensitive MTB. Our preliminary diagnostic results suggest that mutations in katG315 may potentially serve as molecular markers that can be used to diagnose the resistance to anti-TB drug of INH. Conclusion In the Chongqing, DR-TB and MDR-TB are increasing, and are becoming key problems for tuberculosis control. The use of katG315 mutations as potential molecule markers for drug resistance to INH may help improve patient treatment and decrease the spread of the disease展开更多
基金supported by the National Natural Science Foundation of China(11871238,11931019,12371486)。
文摘Drug resistance is one of the most intractable issues in targeted therapy for cancer diseases.It has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory cancer cell populations.Focusing on how cancer cells develop resistance during the encounter with targeted drugs and the immune system,we propose a mathematical model for studying the dynamics of drug resistance in a conjoint heterogeneous tumor-immune setting.We analyze the local geometric properties of the equilibria of the model.Numerical simulations show that the selectively targeted removal of sensitive cancer cells may cause the initially heterogeneous population to become a more resistant population.Moreover,the decline of immune recruitment is a stronger determinant of cancer escape from immune surveillance or targeted therapy than the decay in immune predation strength.Sensitivity analysis of model parameters provides insight into the roles of the immune system combined with targeted therapy in determining treatment outcomes.
基金supported by the National Innovation and Enterpreneurship Training Program for College Students(202210367002)the Key Laboratory Open Project of An-hui Province(AHCM2022Z004).
文摘Objective To identify nivolumab resistance-related genes in patients with head and neck squamous cell carcinoma(HNSCC)using single-cell and bulk RNA-sequencing data.Methods The single-cell and bulk RNA-sequencing data downloaded from the Gene Expression Omnibus database were analyzed to screen out differentially expressed genes(DEGs)between nivolumab resistant and nivolumab sensitive patients using R software.The Least Absolute Shrinkage Selection Operator(LASSO)regression and Recursive Feature Elimination(RFE)algorithm were performed to identify key genes associated with nivolumab resistance.Functional enrichment of DEGs was analyzed with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses.The relationships of key genes with immune cell infiltration,differentation trajectory,dynamic gene expression profiles,and ligand-receptor interaction were explored.Results We found 83 DEGs.They were mainly enriched in T-cell differentiation,PD-1 and PD-L1 checkpoint,and T-cell receptor pathways.Among six key genes identified using machine learning algorithms,only PPP1R14A gene was differentially expressed between the nivolumab resistant and nivolumab sensitive groups both before and after immunotherapy(P<0.05).The high PPP1R14A gene expression group had lower immune score(P<0.01),higher expression of immunosuppressive factors(such as PDCD1,CTLA4,and PDCD1LG2)(r>0,P<0.05),lower differentiation of infiltrated immune cells(P<0.05),and a higher degree of interaction between HLA and CD4(P<0.05).Conclusions PPP1R14A gene is closely associated with resistance to nivolumab in HNSCC patients.Therefore,PPP1R14A may be a target to ameliorate nivolumab resistance of HNSCC patients.
基金supported by grants from the National Key Research and Development Program of China(2021YFF1201300)the National Natural Science Foundation of China(81872280,82073094)+2 种基金the CAMS Innovation Fund for Medical Sciences(CIFMS)(2021-I2M-1-014)the Open Issue of State Key Laboratory of Molecular Oncology(SKL-KF-2021-16)the Independent Issue of State Key Laboratory of Molecular Oncology(SKL-2021-16).
文摘Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle.However,the patterns of transcript isoform expression in the cell cycle are unclear.Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies,but none of them have been designed or evaluated at the alternative splicing transcript level.The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown,and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare.Methods:To explore alternative splicing patterns during cell cycle progression,we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines,using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples,and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle.Genomics of Drug Sensitivity in Cancer(GDSC)drug sensitivity datasets and Cancer Cell Line Encyclopedia(CCLE)transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity.We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients.Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6(CDK4/6)inhibitors.Finally,alternative splicing transcripts associated with mitotic(M)phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis.Results:We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells.The results of the cell cycle assessment showed that 43,326,41,578 and 29,244 transcripts were found to be periodically expressed in HeLa,HCT116 and MDA-MB-231 cells,respectively,among which 1280 transcripts showed this expression pattern in all three cancer cell lines.Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes.Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904.The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts.Combined with the cell cycle-related drug screening,the results also showed that a set of periodic transcripts,for example,ENST00000314392(a dolichylphosphate mannosyltransferase polypeptide 2 isoform transcript),was more associated with drug sensitivity than the levels of their corresponding gene transcripts.Conclusions:In summary,we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity,providing novel insights into alternative splicing-related drug development and evaluation.
基金Supported by the Natural Science Foundation of Universities of Anhui Province (KJ2008A152)the Natural Science Foundation of the Committee of Education of Anhui Province (2005KJ238)
文摘To study the characteristics of drug-resistant genetic mutation of rpoB on coal workers＇ pneumoconiosis complicated with L-form of Mycobacterium tuberculosis. Methods： A total of 42 clinical isolated strains of Mycobacterium tuberculosis L-forms were collected, including 31 drug-resistant strains. Their genomes DNA were extracted, the target genes were amplified by PCR, and the hot regions in the rpoB gene were analyzed by automated DNA sequenator. Results： No mutation of rpoB gene was identified in 11 rifampicin-sensitive strains while conformation changes were found in 31 rifampicin-resistant strains. The mutation rate was 93.55% （29/31） in resistant strains, mainly concentrated in codon 531 （51.6%, 16/31） and 526 （32.26%, 10/31）. Base substitutions happened, including 27 unit point mutation and 2 two point mutation. The mutation of codon 516 that new found wasn＇t reported by internal and overseas scholars. Conclusion： The substitution of highly conserved amino acids encoded by rpoB gene results in the molecular mechanism responsible for rifampicin resistance in Mycobacterium tuberculosis L-forms. It also proves that rpoB gene is diversiform.
基金Supported by the National Natural Scientific Foundation of China (No. 30170396)
文摘Objective：To investigate the expression of CXCR4 on HL-60 cell line and the proliferation, apoptosis of HL-60 cell line cocultured with bone marrow stromal cells, so as to assess the possibility of 12G5, an anti-CXCR4 monoclonal antibody, in eradicating the minimal residual disease. Methods：The activity of SDF-1 was inhibited by 10 μg/ml 12G5. After treatment with 12G5, the status of adhesion was observed, and the adhesion rates, apoptosis and cell cycles were detected after 24 h of treatment. Cell growth rates were measured by trypan blue exclusion. Cell growth curve was plotted, and the expression of PCNA and apoptosis related protein including PCNA, Bcl-2 and Fas were detected with immunohistochemical technique. Results：（1） There was middling degree expression of CXCR4 on HL-B0 membrane. From 0 h to 6 h, as the time of 12G5 incubation along, the expression of CXCR4 decreased gradually. （2） After treatment for 24 h, the adhesion rates in the experiment group and the control were （39.4±7.9）% and （51.4±5.9）%, respectively. （3）After treatment for 24 h, the percentage of HL-60 cells in G0/G1 phase were （55.21±4.9）%, and that in S phase and G2/M phase were （30.40±4.1）% and （14.39± 5.2）%, respectively, with the corresponding proportions being （44. 67±2.2）%, （45.30±3.7）%, and （10. 03±2.6）% in the control. （4） The percentage of apoptotic HL-60 cells was （8.95±1.7）% in the experiment group, compared to （3. 97±2. 4）% in the control. （5）The survival rates of HL-60 cells decreased markedly at 48 h to 96 h, and the proliferation slowed down at this time duration. （6）The expression of PCNA and Bcl-2 down-regulated significantly, but the Fas protein expression was up-regulated. Conclusion：12G5 could inhibit the capability of adhesion and proliferation of HL-60 cells and it can induce more cells to enter G0/G1 phase and promote apoptosis. It may be helpful by inhibiting the bioactivity of SDF-1 with 12G5 in the therapy of marrow residual disease.
文摘P-glycoprotein plays an important role in highly drug resistant cells. But its high expression cannot be acheived by chemotherapy. In order to study the effect of P-glycoprotein on clinical tumors, we established a low ADM resistant colon cancer cell line HR/ADM and determined the amplification and expression of mdr-1 gene. The GLC/ADM showed a resistant pattern similar to classical MDR and the transcription of mdr-1 gene determined by RT-PCR increased. The immunocytochemical analysis showed strong positive staining with monoclonal antibody. The gene amplification of mdr-1 was clearly demonstrated by southernblot. Our results suggested that moderate expression of P-glycoprotein might be enough for a high resistantpattern.
基金Supported by the Natural Science Foundation for Universities in Anhui Province (KJ2010A087 and KJ2008A152)
文摘Objective： To study the effect of the extract of Prunella vulgaris L. on multiple drugs resistant bacillus tuberculosis （MDR-TB）. Methods： Experimental animal model in rats was induced by MDR-TB. Normal group model group and Prunella vulgaris L. group were set up. The contents of IFN-7, IL-4, IL-10 and IL-12 were examined by ELISA. Their genome mRNAs were extracted, the target genes were amplified by PCR. RT-PCR was used to detect the mRNA levels of them. Results： The content of IFN-q, of the extract of Prunella vulgaris L. group was 1.98±0.67 pg/ml, IL-4 was 6.47±1.46 pg/ml, IL-10 was 12.13±3.43 pg/ml and IL-12 was 3.02±0.86 pg/ml. Compared with the model group, Prunella vulgaris L. group was notable difference in serum IFN-γ, IL-12 and IL-10 （P〈0.05）. The mRNA levels of IFN-γ, IL-12 increased and IL-10 decreased obviously, the differences were quite significant （P〈0.05）, but IL-4 had no obvious change. Conclusion： The extract of Prunella vulgaris L. can enhance the cellar immunological function in rats from up-regulation of the level of genetic transcription, accordingly provide the theory basis of healing of tuberculosis with it.
基金Supported by the National Natural Science Foundation of China(30700685)the Medical Science and Technology Research Project of Chongqing Municipal Health Bureau(2009-1-06)
文摘Background The epidemiological characteristics of drug-resistant tuberculosis （DR-TB） is fundamental to improving the prevention and control of DR-TB. Mutations in katG315 is thought to be the most predictive molecule markers for Isoniazid （INH） resistance in Mycobacterium tuberculosis （MTB）. However, mutations to these genes have not been thoroughly studied in China, and epidemiological evidence of their expression levels are especially lacking in the southwest of China, which has a high TB burden within the population. Methods MTB isolates were obtained from patients with active pulmonary tuberculosis at the TB dispensary and Chest hospital in Chongqing city between June 2003 and June 2006. Proportion methods were used to test the sensitivity to INH, RFP, SM and EMB of cultured MTB. A total of 100 MTB isolates were also randomly selected for analysis of the molecular mutation spectrum of katG by DNA sequencing. Results Totally 1 089 MTB isolates that completed positive sputum cultures and evaluated for their sensitivity to the four first-line drugs among 2 777 patients with TB. The prevalence of DR-TB and multi-drug resistant tuberculosis （MDR-TB） were 27.7% （302/1 089） and 7.3% （79/1 089）, respectively. The resistance to anti-TB drugs was found to be highest for SM （16.3%） and INH （14.0%）. There was also a significant increase in the prevalence of resistance to RFP and EMB （P〈0.01）, and an increase in MDR-TB between June 2003 and June 2004 and between July 2005 and June 2006. The total mutation rate of katG315 was 75＂5% （37/49） in INH-resistant MTB, and mutation sites included $315T, $315N and $315I with mutation rates of 81.1% （30/37）, 13.5% （5/37） and 5.4% （2/37）, respectively No katG315 mutants were found in any of the 48 INH-sensitive MTB. Our preliminary diagnostic results suggest that mutations in katG315 may potentially serve as molecular markers that can be used to diagnose the resistance to anti-TB drug of INH. Conclusion In the Chongqing, DR-TB and MDR-TB are increasing, and are becoming key problems for tuberculosis control. The use of katG315 mutations as potential molecule markers for drug resistance to INH may help improve patient treatment and decrease the spread of the disease
