Since the approval of gemtuzumab ozogamicin,an antibody-drug conjugate(ADC)targeting CD33 in 2000,13 ADC drugs have been approved by the FDA.Although these drugs have clearly improved the survival of patients with various types of advanced cancers,their significant toxicity has compromised their therapeutic benefits.The adverse reactions of ADC drugs are complex and include on-target and off-target toxicities,where the payload drug is a determining factor.Antibody and linker may also affect the degree of toxicity.Combination therapy becomes an important strategy in anticancer treatment because of its increased efficiency,but treatment-related adverse reactions also increase accordingly.This review comprehensively analyzes the toxicity mechanisms of current ADC drugs and proposes various optimization strategies,including but not limited to optimizing linker molecules,upgrading antibody design,and changing drug administration strategies,to improve the overall safety profile of ADC drugs.

Objective To explore the correlation of CPNE3 expression with long-term prognosis of patients with gastric cancer(GC)and the possible mechanism.Methods We retrospectively collected the data of 104 GC patients undergoing radical surgery in our hospital from February,2013 to October,2017.TCGA database and immunohistochemistry were used to analyze CPNE3 expression level in GC tissues and its effects on tumor progression and long-term prognosis of the patients.GO analysis was performed to predict the biological role of CPNE3 in GC.We also conducted cell experiments with MGC803 cells and observed the effects of CPNE3 knockdown,CPNE3 overexpression and LY294002(a PI3K/AKT inhibitor)treatment on cell apoptosis and cellular expressions of apoptotic proteins using flow cytometry and Western blotting.Results TCGA analysis and immunohistochemistry both showed high expressions of CPNE3 in GC(P<0.05).The patients with high CPNE3 expressions had a reduced 5-year survival(P<0.01),and a high CPNE3 expression,CEA level≥5 μg/L,CA19-9 level≥37 kU/L,T3-T4 stage,and N2-N3 stage were all independent risk factors for a lowered 5-year survival rate after surgery.The sensitivity and specificity of CPNE3 for predicting 5-year mortality was 79.59%and 74.55%,respectively(P<0.05).GO analysis predicted that CPNE3 negatively regulated GC cell apoptosis.In MGC803 cells,CPNE3 knockdown significantly increased cell apoptosis,enhanced Bax and Cleaved Caspase-3 expressions and decreased Bcl-2 expression,while CPNE3 overexpression produced the opposite results(P<0.05).The cellular expressions of p-PI3K and p-AKT were significantly decreased following CPNE3 knockdown and increased following CPNE3 overexpression(P<0.05).Treatment with LY294002 obviously attenuated the inhibitory effect of CPNE3 overexpression on apoptosis of MGC803 cells(P<0.05).Conclusion CPNE3 is highly expressed in GC tissues and affects the long-term prognosis of the patients possibly by inhibiting GC cell apoptosis through activation of PI3K/AKT signaling.

Objective To analyze the expression level of ATP5A1 in gastric carcinoma and its influence on the prognosis of the patients and glucose metabolism in the tumor cells.Methods We retrospectively analyzed the data of 115 patients undergoing radical resection of gastric carcinoma in our hospital from February,2013 to November,2016.ATP5A1 expression in the surgical specimens were detected using immunohistochemistry,and the long-term prognosis of the patients with high(n=58)and low ATP5A1 expression(n=57)were analyzed.In gastric carcinoma MGC803 cells,the effects of lentivirus-mediated ATP5A1 knockdown or overexpression on glucose metabolism were investigated.We also observed the growth and glucose metabolism of xenografts derived from MGC803 cells with ATP5A1 knockdown or overexpression in nude mice.Results ATP5A1 was significantly overexpressed in gastric carcinoma tissues in close correlation with blood CEA and CA19-9 levels,pathological grade,T stage and N stage(P<0.05).ATP5A1 overexpression was an independent risk factor for a significantly lowered 5-year survival rate of patients with gastric carcinoma(P<0.05).ROC curve analysis demonstrated the predictive value of high ATP5A1 expression for the patients'prognosis(P<0.001).In MGC803 cells,ATP5A1 overexpression significantly up-regulated cellular glucose uptake and lactate production and increased the protein levels of HK2,PFK1,and LDHA(P<0.05),while ATP5A1 knockdown produced the opposite changes(P<0.05).In the tumor-bearing mice,overexpression of ATP5A1 increased glucose metabolism of the tumor cells and promoted tumor growth(P<0.05).Overexpression of ATP5A1 promoted the expressions of p-JNK and p-JUN in MGC803 cells(P<0.05),and the JNK inhibitor SP600125 significantly inhibited the enhancement of cellular glucose metabolism induced by ATP5A1 overexpression(P<0.05).Conclusion High ATP5A1 expression in gastric cancer is associated a poor long-term prognosis of the patients,and its effect is mediated at least partly by promoting glucose metabolism of the cells through the JNK/JUN pathway.

Objective To explore the correlation of CPNE3 expression with long-term prognosis of patients with gastric cancer(GC)and the possible mechanism.Methods We retrospectively collected the data of 104 GC patients undergoing radical surgery in our hospital from February,2013 to October,2017.TCGA database and immunohistochemistry were used to analyze CPNE3 expression level in GC tissues and its effects on tumor progression and long-term prognosis of the patients.GO analysis was performed to predict the biological role of CPNE3 in GC.We also conducted cell experiments with MGC803 cells and observed the effects of CPNE3 knockdown,CPNE3 overexpression and LY294002(a PI3K/AKT inhibitor)treatment on cell apoptosis and cellular expressions of apoptotic proteins using flow cytometry and Western blotting.Results TCGA analysis and immunohistochemistry both showed high expressions of CPNE3 in GC(P<0.05).The patients with high CPNE3 expressions had a reduced 5-year survival(P<0.01),and a high CPNE3 expression,CEA level≥5 μg/L,CA19-9 level≥37 kU/L,T3-T4 stage,and N2-N3 stage were all independent risk factors for a lowered 5-year survival rate after surgery.The sensitivity and specificity of CPNE3 for predicting 5-year mortality was 79.59%and 74.55%,respectively(P<0.05).GO analysis predicted that CPNE3 negatively regulated GC cell apoptosis.In MGC803 cells,CPNE3 knockdown significantly increased cell apoptosis,enhanced Bax and Cleaved Caspase-3 expressions and decreased Bcl-2 expression,while CPNE3 overexpression produced the opposite results(P<0.05).The cellular expressions of p-PI3K and p-AKT were significantly decreased following CPNE3 knockdown and increased following CPNE3 overexpression(P<0.05).Treatment with LY294002 obviously attenuated the inhibitory effect of CPNE3 overexpression on apoptosis of MGC803 cells(P<0.05).Conclusion CPNE3 is highly expressed in GC tissues and affects the long-term prognosis of the patients possibly by inhibiting GC cell apoptosis through activation of PI3K/AKT signaling.

Objective To analyze the expression level of ATP5A1 in gastric carcinoma and its influence on the prognosis of the patients and glucose metabolism in the tumor cells.Methods We retrospectively analyzed the data of 115 patients undergoing radical resection of gastric carcinoma in our hospital from February,2013 to November,2016.ATP5A1 expression in the surgical specimens were detected using immunohistochemistry,and the long-term prognosis of the patients with high(n=58)and low ATP5A1 expression(n=57)were analyzed.In gastric carcinoma MGC803 cells,the effects of lentivirus-mediated ATP5A1 knockdown or overexpression on glucose metabolism were investigated.We also observed the growth and glucose metabolism of xenografts derived from MGC803 cells with ATP5A1 knockdown or overexpression in nude mice.Results ATP5A1 was significantly overexpressed in gastric carcinoma tissues in close correlation with blood CEA and CA19-9 levels,pathological grade,T stage and N stage(P<0.05).ATP5A1 overexpression was an independent risk factor for a significantly lowered 5-year survival rate of patients with gastric carcinoma(P<0.05).ROC curve analysis demonstrated the predictive value of high ATP5A1 expression for the patients'prognosis(P<0.001).In MGC803 cells,ATP5A1 overexpression significantly up-regulated cellular glucose uptake and lactate production and increased the protein levels of HK2,PFK1,and LDHA(P<0.05),while ATP5A1 knockdown produced the opposite changes(P<0.05).In the tumor-bearing mice,overexpression of ATP5A1 increased glucose metabolism of the tumor cells and promoted tumor growth(P<0.05).Overexpression of ATP5A1 promoted the expressions of p-JNK and p-JUN in MGC803 cells(P<0.05),and the JNK inhibitor SP600125 significantly inhibited the enhancement of cellular glucose metabolism induced by ATP5A1 overexpression(P<0.05).Conclusion High ATP5A1 expression in gastric cancer is associated a poor long-term prognosis of the patients,and its effect is mediated at least partly by promoting glucose metabolism of the cells through the JNK/JUN pathway.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.

Objective To examine the changing antimicrobial resistance profile of Enterobacter spp.isolates in 53 hospitals across China from 2015 t0 2021.Methods The clinical isolates of Enterobacter spp.were collected from 53 hospitals across China during 2015-2021 and tested for antimicrobial susceptibility using Kirby-Bauer method or automated testing systems according to the CHINET unified protocol.The results were interpreted according to the breakpoints issued by the Clinical & Laboratory Standards Institute(CLSI)in 2021(M100 31st edition)and analyzed with WHONET 5.6 software.Results A total of 37 966 Enterobacter strains were isolated from 2015 to 2021.The proportion of Enterobacter isolates among all clinical isolates showed a fluctuating trend over the 7-year period,overall 2.5％in all clinical isolates amd 5.7％in Enterobacterale strains.The most frequently isolated Enterobacter species was Enterobacter cloacae,accounting for 93.7％(35 571/37 966).The strains were mainly isolated from respiratory specimens(44.4±4.6)％,followed by secretions/pus(16.4±2.3)％and urine(16.0±0.9)％.The strains from respiratory samples decreased slightly,while those from sterile body fluids increased over the 7-year period.The Enterobacter strains were mainly isolated from inpatients(92.9％),and only(7.1±0.8)％of the strains were isolated from outpatients and emergency patients.The patients in surgical wards contributed the highest number of isolates(24.4±2.9)％compared to the inpatients in any other departement.Overall,≤ 7.9％of the E.cloacae strains were resistant to amikacin,tigecycline,polymyxin B,imipenem or meropenem,while ≤5.6％of the Enterobacter asburiae strains were resistant to these antimicrobial agents.E.asburiae showed higher resistance rate to polymyxin B than E.cloacae(19.7％vs 3.9％).Overall,≤8.1％of the Enterobacter gergoviae strains were resistant to tigecycline,amikacin,meropenem,or imipenem,while 10.5％of these strains were resistant to polycolistin B.The overall prevalence of carbapenem-resistant Enterobacter was 10.0％over the 7-year period,but showing an upward trend.The resistance profiles of Enterobacter isolates varied with the department from which they were isolated and whether the patient is an adult or a child.The prevalence of carbapenem-resistant E.cloacae was the highest in the E.cloacae isolates from ICU patients.Conclusions The results of the CHINET Antimicrobial Resistance Surveillance Program indicate that the proportion of Enterobacter strains in all clinical isolates fluctuates slightly over the 7-year period from 2015 to 2021.The Enterobacter strains showed increasing resistance to multiple antimicrobial drugs,especially carbapenems over the 7-year period.

Objective To understand the changing distribution and antimicrobial resistance profiles of Proteus,Morganella and Providencia in hospitals across China from January 1,2015 to December 31,2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods Antimicrobial susceptibility testing was carried out following the unified CHINET protocol.The results were interpreted in accordance with the breakpoints in the 2021 Clinical & Laboratory Standards Institute(CLSI)M100(31 st Edition).Results A total of 32 433 Enterobacterales strains were isolated during the 7-year period,including 24 160 strains of Proteus,6 704 strains of Morganella,and 1 569 strains of Providencia.The overall number of these Enterobacterales isolates increased significantly over the 7-year period.The top 3 specimen source of these strains were urine,lower respiratory tract specimens,and wound secretions.Proteus,Morganella,and Providencia isolates showed lower resistance rates to amikacin,meropenem,cefoxitin,cefepime,cefoperazone-sulbactam,and piperacillin-tazobactam.For most of the antibiotics tested,less than 10％of the Proteus and Morganella strains were resistant,while less than 20％of the Providencia strains were resistant.The prevalence of carbapenem-resistant Enterobacterales(CRE)was 1.4％in Proteus isolates,1.9％in Morganella isolates,and 15.6％in Providencia isolates.Conclusions The overall number of clinical isolates of Proteus,Morganella and Providencia increased significantly in the 7-year period from 2015 to 2021.The prevalence of CRE strains also increased.More attention should be paid to antimicrobial resistance surveillance and rational antibiotic use so as to prevent the emergence and increase of antimicrobial resistance.