1.Role of antibiotic delivery system targeting bacterial biofilm based on ε-poly- L-lysine and cyclodextrin in treatment of bone and joint infections.
Tiexin LIU ; Junqing LIN ; Xianyou ZHENG
Chinese Journal of Reparative and Reconstructive Surgery 2025;39(3):362-369
OBJECTIVE:
To explore the mechanism of antibiotic delivery system targeting bacterial biofilm with linezolid (LZD) based on ε-poly- L-lysine (ε-PLL) and cyclodextrin (CD) (ε-PLL-CD-LZD), aiming to enhance antibiotic bioavailability, effectively penetrate and disrupt biofilm structures, and thereby improve the treatment of bone and joint infections.
METHODS:
ε-PLL-CD-LZD was synthesized via chemical methods. The grafting rate of CD was characterized using nuclear magnetic resonance. In vitro biocompatibility was evaluated through live/dead cell staining after co-culturing with mouse embryonic osteoblast precursor cells (MC3T3-E1), human umbilical vein endothelial cells, and mouse embryonic fibroblast cells (3T3-L1). The biofilm-enrichment capacity of ε-PLL-CD-LZD was assessed using Staphylococcus aureus biofilms through enrichment studies. Its biofilm eradication efficacy was investigated via minimum inhibitory concentration (MIC) determination, scanning electron microscopy, and live/dead bacterial staining. A bone and joint infection model in male Sprague-Dawley rats was established to validate the antibacterial effects of ε-PLL-CD-LZD.
RESULTS:
In ε-PLL-CD-LZD, the average grafting rate of CD reached 9.88%. The cell viability exceeded 90% after co-culturing with three types cells. The strong biofilm enrichment capability was observed with a MIC of 2 mg/L. Scanning electron microscopy observations revealed the effective disruption of biofilm structure, indicating potent biofilm eradication capacity. In vivo rat experiments demonstrated that ε-PLL-CD-LZD significantly reduced bacterial load and infection positivity rate at the lesion site ( P<0.05).
CONCLUSION
The ε-PLL-CD antibiotic delivery system provides a treatment strategy for bone and joint infections with high clinical translational significance. By effectively enhancing antibiotic bioavailability, penetrating, and disrupting biofilms, it demonstrated significant anti-infection effects in animal models.
Biofilms/drug effects*
;
Animals
;
Anti-Bacterial Agents/pharmacology*
;
Polylysine/chemistry*
;
Cyclodextrins/administration & dosage*
;
Humans
;
Linezolid/pharmacology*
;
Staphylococcus aureus/physiology*
;
Rats, Sprague-Dawley
;
Mice
;
Rats
;
Male
;
Drug Delivery Systems
;
Staphylococcal Infections/drug therapy*
;
Microbial Sensitivity Tests
;
Human Umbilical Vein Endothelial Cells
;
Osteoblasts/cytology*
2.Determination of Acetate Content in Hemodialysis Solutions and Dialysis Concentrates by HPLC.
Huadong WANG ; Yue WANG ; Dong LIU ; Xianghui LIU
Chinese Journal of Medical Instrumentation 2025;49(3):350-354
This study establishes a high-performance liquid chromatography (HPLC) method for the determination of acetate content in hemodialysis solutions and dialysis concentrates. In this study, Synergi Polar-RP column is utilized. Phosphate buffered saline (50 mmol/L, pH=2.5) is used as a mobile phase. The flow rate is 1.0 mL/min. The wavelength of detection is 212 nm. Results show that the linear relationship of acetate is good in the range of 0.1~20 mmol/L, r =0.999 9 and the spike recoveries are from 98.9%~99.5%, RSD<0.5% ( n=3). This method can easily and accurately determine the acetate content in hemodialysis solutions and dialysis concentrates, and can be applied to quality control in the production and use of such products.
Chromatography, High Pressure Liquid/methods*
;
Acetates/analysis*
;
Hemodialysis Solutions/analysis*
;
Dialysis Solutions/analysis*
;
Renal Dialysis
3.Lacticaseibacillus paracasei E6 improves vinorelbine-induced immunosuppression in zebrafish through its metabolites acetic acid and propionic acid.
Xu XINZHU ; Lina GUO ; Kangdi ZHENG ; Yan MA ; Shuxian LIN ; Yingxi HE ; Wen SHENG ; Suhua XU ; Feng QIU
Journal of Southern Medical University 2025;45(2):331-339
OBJECTIVES:
To explore the mechanism of Lacticaseibacillus paracasei E6 for improving vinorelbine-induced immunosuppression in zebrafish.
METHODS:
The intestinal colonization of L. paracasei E6 labeled by fluorescein isothiocyanate (FITC) in zebrafish was observed under fluorescence microscope. In a zebrafish model of vinorelbine-induced immunosuppression, the immunomodulatory activity of L. paracasei E6 was assessed by analyzing macrophage and neutrophil counts in the caudal hematopoietic tissue (CHT), the number of T-lymphocyte, and the expressions of interleukin-12 (IL-12) and interferon-γ (IFN-γ). The contents of short-chain fatty acids (SCFAs) in L. paracasei E6 fermentation supernatant and the metabolites of L. paracasei E6 in zebrafish were detected by LC-MS/MS-based targeted metabolomics. The immunomodulatory effects of the SCFAs including sodium acetate, sodium propionate and sodium butyrate were evaluated in the zebrafish model of immunosuppression.
RESULTS:
After inoculation, green fluorescence of FITC-labeled L. paracasei E6 was clearly observed in the intestinal ball, midgut and posterior gut regions of zebrafish. In the immunocompromised zebrafish model, L. paracasei E6 significantly alleviated the reduction of macrophage and neutrophil counts in the CHT, increased the fluorescence intensity of T-lymphocytes, and promoted the expressions of IL-12 and IFN-γ. Compared with MRS medium, L. paracasei E6 fermentation supernatant showed significantly higher levels of acetic acid, propionic acid and butyric acid, which were also detected in immunocompromised zebrafish following treatment with L. paracasei E6. Treatment of the zebrafish model with sodium acetate and sodium propionate significantly increased macrophage and neutrophil counts in the CHT and effectively inhibited vinorelbine-induced reduction of thymus T cells.
CONCLUSIONS
L. paracasei E6 can improve vinorelbine-induced immunosuppression in zebrafish through its SCFA metabolites acetic acid and propionic acid.
Animals
;
Zebrafish/immunology*
;
Acetic Acid/metabolism*
;
Propionates/metabolism*
;
Fatty Acids, Volatile/metabolism*
4.Acupuncture at Weizhong (BL40) attenuates acetic acid-induced overactive bladder in rats by regulating brain neural activity through the modulation of mast cells and tibial nerves.
Xin LIU ; Chao-Yue ZHANG ; Xiu-Yu DU ; Shan-Shan LI ; Yu-Qing WANG ; Yi ZHENG ; Han-Zhi DENG ; Xiao-Qin FANG ; Jia-Ying LI ; Zu-Qing WANG ; Shi-Fen XU ; Yi-Qun MI
Journal of Integrative Medicine 2025;23(1):46-55
OBJECTIVE:
The present study evaluated the effects of deep acupuncture at Weizhong acupoint (BL40) on bladder function and brain activity in a rat model of overactive bladder (OAB), and investigated the possible mechanisms around the acupuncture area that initiate the effects of acupuncture.
METHODS:
Adult female Sprague-Dawley rats were randomly divided into six groups, comprising a control group, model group, group treated with deep acupuncture at BL40, group treated with shallow acupuncture at BL40, group treated with acupuncture at non-acupoint next to BL40, and group treated with acupuncture at Xuanzhong (GB39). Urodynamic evaluation was used to observe the urination, and functional magnetic resonance imaging was used to observe the brain activation. The mechanism of acupuncture at BL40 in regulating bladder function was explored by toluidine blue staining and enzyme-linked immunosorbent assay, and the mechanism was verified by stabilizing mast cells (MCs) or blocking tibial nerve.
RESULTS:
Deep acupuncture at BL40 significantly increased the intercontraction interval in OAB rats and enhanced the mean amplitude of low frequency fluctuation of primary motor cortex (M1), periaquaductal gray matter (PAG), and pontine micturition center (PMC). It also increased the zero-lag functional connectivity between M1 and PAG and between PAG and PMC. Shallow acupuncture at BL40 and acupuncture at non-acupoint or GB39 had no effect on these indexes. Further studies suggested that deep acupuncture at BL40 increased the number and degranulation rate of MCs as well as the contents of 5-hydroxytryptamine, substance P, and histamine in the tissues around BL40. Blocking the tibial nerve by lidocaine injection or inhibiting MC degranulation by sodium cromoglycate injection obstructed the effects of acupuncture on restoring urinary function and modulating brain activation in OAB rats.
CONCLUSION
Deep acupuncture at BL40 may be more effective for inhibiting OAB by promoting degranulation of MCs around the acupoint and stimulating tibial nerve, thereby regulating the activation of the brain area that controls the lower urinary tract. Please cite this article as: Liu X, Zhang CY, Du XY, Li SS, Wang YQ, Zheng Y, Deng HZ, Fang XQ, Li JY, Wang ZQ, Xu SF, Mi YQ. Acupuncture at Weizhong (BL40) attenuates acetic acid-induced overactive bladder in rats by regulating brain neural activity through the modulation of mast cells and tibial nerves. J Integr Med. 2025; 23(1): 46-55.
Animals
;
Urinary Bladder, Overactive/physiopathology*
;
Mast Cells/physiology*
;
Rats, Sprague-Dawley
;
Female
;
Acupuncture Therapy
;
Acupuncture Points
;
Rats
;
Brain/physiopathology*
;
Tibial Nerve/physiopathology*
;
Acetic Acid
;
Urinary Bladder/physiopathology*
5.Cloning and functional analysis of the phenylalanine ammonia-lyase gene from Anthoceros angustus.
Haina YU ; Jian MO ; Jiayi YANG ; Xiaochun QIN
Chinese Journal of Biotechnology 2025;41(7):2855-2870
Anthoceros angustus Steph. is rich in phenolic acids such as rosmarinic acid (RA). Phenylalanine ammonia-lyase (PAL) is an entry enzyme in the phenylpropanoid pathway of plants, playing an important role in the biosynthesis of RA. To investigate the important role of PAL in rosmarinic acid synthesis, two PAL genes (designated as AanPAL1 and AanPAL2) were cloned from A. angustus, encoding 755 and 753 amino acid residues, respectively. The AanPAL deduced amino acid sequences contain the conserved domains of PAL and the core active amino acid residues Ala-Ser-Gly. The phylogenetic analysis indicated that AanPAL1 and AanPAL2 were clustered with PALs from bryophytes and ferns and had the shortest evolutionary distance with the PALs from Physcomitrella patens. Quantitative real-time PCR results showed that the expression of AanPAL1 and AanPAL2 was induced by exogenous methyl jasmonate (MeJA). HPLC results showed that the MeJA treatment significantly increased the accumulation of RA. AanPAL1 and AanPAL2 were expressed in Escherichia coli and purified by histidine-tag affinity chromatography. The recombinant proteins catalyzed the conversion of L-phenylalanine to generate trans-cinnamic acid with high efficiency, with the best performance at 50 ℃ and pH 8.0. The Km and kcat of AanPAL1 were 0.062 mmol/L and 4.35 s-1, and those of AanPAL2 were 0.198 mmol/L and 14.48 s-1, respectively. The specific activities of AanPAL1 and AanPAL2 were 2.61 U/mg and 8.76 U/mg, respectively. The two enzymes had relatively poor thermostability but good pH stability. The high activity of AanPAL2 was further confirmed via whole-cell catalysis with recombinant E. coli, which could convert 1 g/L L-phenylalanine into trans-cinnamic acid with a yield of 100% within 10 h. These results give insights into the regulatory role of AanPAL in the biosynthesis of RA in A. angustus and provide candidate enzymes for the biosynthesis of cinnamic acid.
Phenylalanine Ammonia-Lyase/metabolism*
;
Cloning, Molecular
;
Cinnamates/metabolism*
;
Recombinant Proteins/metabolism*
;
Rosmarinic Acid
;
Depsides/metabolism*
;
Escherichia coli/metabolism*
;
Amino Acid Sequence
;
Plant Proteins/metabolism*
;
Phylogeny
;
Acetates/pharmacology*
;
Cyclopentanes
;
Oxylipins
6.Differences in toxicity and serum metabolomics of ethyl acetate fraction of Euphorbiae Pekinensis Radix before and after vinegar processing.
Xia SHAO ; Li ZHANG ; Yu-Dan CAO
China Journal of Chinese Materia Medica 2024;49(21):5888-5897
This study aimed to investigate the toxicity differences of the ethyl acetate fraction of Euphorbiae Pekinensis Radix before and after vinegar processing and explore the detoxification mechanism of vinegar processing using non-targeted metabolomics. The changes in terpenoid components in the ethyl acetate fraction before and after vinegar processing were analyzed using UFLC-Q-TOF-MS. Normal rats were orally administered the raw and vinegar-processed ethyl acetate fractions of Euphorbia Pekinensis Radix. The toxicity differences in ethyl acetate fractions of Euphorbia Pekinensis Radix before and after vinegar processing were evaluated by pathological morphology, serum liver and kidney function, oxidative damage, and inflammatory injury indicators, and apoptosis factors. Serum metabolomics technology was utilized to identify changes in endogenous metabolites. Principal component analysis(PCA) and partial least squares discriminant analysis(PLS-DA) were employed to identify differential metabolites and metabolic pathways related to the detoxification of vinegar-processed Euphorbia Pekinensis Radix. The content of terpenoid components in the ethyl acetate fraction of Euphorbia Pekinensis Radix significantly decreased after vinegar processing. Histopathological sections and various indicators revealed that both the raw and vinegar-processed ethyl acetate fractions of Euphorbia Pekinensis Radix could induce toxicity in the liver, stomach, and intestine, with a reduction after vinegar processing. The toxicity was associated with oxidative damage, inflammatory injury, and apoptosis. A total of 13 differential metabolites and 5 main metabolic pathways related to Euphorbia Pekinensis Radix toxicity were identified by serum metabolomics. PCA and PLS-DA score plots indicated that both the raw and vinegar-processed ethyl acetate fractions disrupted the endogenous metabolic profiles in rats, mainly concentrating on lipid metabolism, primary bile acid biosynthesis, and arachidonic acid metabolism, with vinegar processing alleviating these metabolic disruptions. Therefore, the ethyl acetate fraction of Euphorbia Pekinensis Radix possesses liver, stomach, and intestinal toxicity, and vinegar processing reduces its toxicity by decreasing the content of terpenoid components. The detoxification mechanism may be related to alleviating oxidative damage, inflammatory injury, apoptosis, and improving lipid metabolism.
Euphorbia/chemistry*
;
Animals
;
Acetic Acid
;
Metabolomics
;
Rats
;
Acetates/chemistry*
;
Male
;
Drugs, Chinese Herbal/chemistry*
;
Rats, Sprague-Dawley
;
Liver/metabolism*
7.Regulation of Bifidobacterium-short chain fatty acid metabolism and improvement of intestinal toxicity of vinegar-processed Euphorbiae Pekinensis Radix.
Ling-Jun YE ; Xiao-Fen XU ; Sai-Ya CHEN ; Huan ZHANG ; Yi-Xuan GAN ; Tao MENG ; Rui DING ; Jing LI ; Gang CAO ; Kui-Long WANG
China Journal of Chinese Materia Medica 2024;49(23):6331-6341
To explore the mechanism by which vinegar-processed Euphorbiae Pekinensis Radix regulates gut microbiota and reduces intestinal toxicity, this study aimed to identify key microbial communities related to vinegar-induced detoxification and verify their functions. Using a derivatization method, the study measured the content of short-chain fatty acids(SCFAs) in feces before and after vinegar-processing of Euphorbiae Pekinensis Radix. Combined with the results of previous gut microbiota sequencing, correlation analysis was used to identify key microbial communities related to SCFAs content. Through single-bacterium transplantation experiments, the role of key microbial communities in regulating SCFAs metabolism and alleviating the intestinal toxicity of Euphorbiae Pekinensis Radix was clarified. Fecal extracts were then added to a co-culture system of Caco-2 and RAW264.7 cells, and toxicity differences were evaluated using intestinal tight junction proteins and inflammatory factors as indicators. Additionally, the application of a SCFAs receptor blocker helped confirm the role of SCFAs in reducing intestinal toxicity during vinegar-processing of Euphorbiae Pekinensis Radix. The results of this study indicated that vinegar-processing of Euphorbiae Pekinensis Radix improved the decline in SCFAs content caused by the raw material. Correlation analysis revealed that Bifidobacterium was positively correlated with the levels of acetic acid, propionic acid, isobutyric acid, n-butyric acid, isovaleric acid, and n-valeric acid. RESULTS:: from single-bacterium transplantation experiments demonstrated that Bifidobacterium could mitigate the reduction in SCFAs content induced by raw Euphorbiae Pekinensis Radix, enhance the expression of tight junction proteins, and reduce intestinal inflammation. Similarly, cell experiment results confirmed that fecal extracts from Bifidobacterium-transplanted mice alleviated inflammation and increased the expression of tight junction proteins in intestinal epithelial cells. The use of the free fatty acid receptor-2 inhibitor GLPG0974 verified that this improvement effect was related to the SCFAs pathway. This study demonstrates that Bifidobacterium is the key microbial community responsible for reducing intestinal toxicity in vinegar-processed Euphorbiae Pekinensis Radix. Vinegar-processing increases the abundance of Bifidobacterium, elevates the intestinal SCFAs content, inhibits intestinal inflammation, and enhances the expression of tight junction proteins, thereby improving the intestinal toxicity of Euphorbiae Pekinensis Radix.
Animals
;
Mice
;
Humans
;
Acetic Acid/chemistry*
;
Gastrointestinal Microbiome/drug effects*
;
Fatty Acids, Volatile/metabolism*
;
Bifidobacterium/genetics*
;
Caco-2 Cells
;
Intestines/microbiology*
;
Drugs, Chinese Herbal/chemistry*
;
Euphorbia/toxicity*
;
RAW 264.7 Cells
;
Male
;
Feces/chemistry*
;
Intestinal Mucosa/drug effects*
8.Identification and functional analysis of the transcriptional factor GeERF4B-1 in Gelsemium elegans.
Chuihuai YOU ; Ruiqi CHEN ; Xinlu SUN ; Yingying LI ; Yachun SU
Chinese Journal of Biotechnology 2024;40(11):4198-4210
Gelsemium elegans, a vine plant of Loganiaceae, has both medicinal and forage values. However, it is susceptible to low temperatures during growth. Exploring low temperature response genes is of great significance for cold resistance breeding of G. elegans. Ethylene response factors (ERFs) are the transcription factors of the AP2/ERF superfamily and play a crucial role in plant stress response. In this study, based on the unigene GeERF involved in the response to low temperature stress in the transcriptome of G. elegans, a full-length cDNA sequence of the transcription factor GeERF4B-1 was cloned from the leaves of G. elegans by reverse transcription-polymerase chain reaction (RT-PCR). Bioinformatics analysis showed that GeERF4B-1 had an open reading frame of 759 bp, encoding a protein composed of 252 amino acid residues and with a relative molecular weight of 27 kDa. The deduced protein was predicted to be an unstable, alkaline, and hydrophilic protein. The phylogenetic tree showed that GeERF4B-1 was in the same clade as the B-4 subfamily of the ERF family. The results of the subcellular localization experiment revealed that GeERF4B-1 was located in the nucleus. Real time quantitative PCR (RT-qPCR) analysis indicated that GeERF4B-1 was expressed in the root, stem, and leaf of G. elegans, with the highest expression level in the root. Compared with the control, the treatments with a low temperature (4 ℃), methyl jasmonate (MeJA), and abscisic acid (ABA) up-regulated the expression level of GeERF4B-1, which reached the peak at 24-48 h. This result revealed that GeERF4B-1 actively responded to low temperature, MeJA, and ABA stresses. However, both sodium chloride (NaCl) and drought treatments down-regulated the expression of GeERF4B-1. In addition, a prokaryotic expression vector of GeERF4B-1 was constructed, and a fusion protein of approximately 52 kDa was yielded after induced expression. The results of the plate stress assay showed that compared with the control, the prokaryotic strain expressing GeERF4B-1 demonstrated enhanced tolerance to low temperatures and sensitivity to salt and mannitol stresses. This study provides theoretical references and potential genetic resources for breeding G. elegans varieties with stress resistance.
Transcription Factors/metabolism*
;
Plant Proteins/metabolism*
;
Gelsemium/metabolism*
;
Acetates/pharmacology*
;
Gene Expression Regulation, Plant
;
Phylogeny
;
Cold Temperature
;
Amino Acid Sequence
;
Cyclopentanes/metabolism*
;
Oxylipins/metabolism*
;
Stress, Physiological/genetics*
;
Abscisic Acid/metabolism*
;
Cloning, Molecular
9.Characteristics of Gram-positive cocci infection and the therapeutic effect after liver transplantation.
Xiaoxia WU ; Lingli WU ; Lin SHU ; Chenpeng XIE ; Qiquan WAN
Journal of Central South University(Medical Sciences) 2023;48(5):707-715
OBJECTIVES:
Gram-positive cocci is the main pathogen responsible for early infection after liver transplantation (LT), posing a huge threat to the prognosis of liver transplant recipients. This study aims to analyze the distribution and drug resistance of Gram-positive cocci, the risk factors for infections and efficacy of antibiotics within 2 months after LT, and to guide the prevention and treatment of these infections.
METHODS:
In this study, data of pathogenic bacteria distribution, drug resistance and therapeutic efficacy were collected from 39 Gram-positive cocci infections among 256 patients who received liver transplantation from donation after citizens' death in the Third Xiangya Hospital of Central South University from January 2019 to July 2022, and risk factors for Gram-positive cocci infection were analyzed.
RESULTS:
Enterococcus faecium was the dominant pathogenic bacteria (33/51, 64.7%), followed by Enterococcus faecalis (11/51, 21.6%). The most common sites of infection were abdominal cavity/biliary tract (13/256, 5.1%) and urinary tract (10/256, 3.9%). Fifty (98%) of the 51 Gram-positive cocci infections occurred within 1 month after LT. The most sensitive drugs to Gram-positive cocci were teicoplanin, tigecycline, linezolid and vancomycin. Vancomycin was not used in all patients, considering its nephrotoxicity. Vancomycin was not administered to all patients in view of its nephrotoxicity.There was no significant difference between the efficacy of daptomycin and teicoplanin in the prevention of cocci infection (P>0.05). Univariate analysis indicated that preoperative Model for End-Stage Liver Disease (MELD) score >25 (P=0.005), intraoperative red blood cell infusion ≥12 U (P=0.013) and exposure to more than 2 intravenous antibiotics post-LT (P=0.003) were related to Gram-positive cocci infections. Multivariate logistic regression analysis revealed that preoperative MELD score >25 (OR=2.378, 95% CI 1.124 to 5.032, P=0.024) and intraoperative red blood cell transfusion ≥ 12 U (OR=2.757, 95% CI 1.227 to 6.195, P=0.014) were independent risk factors for Gram-positive cocci infections after LT. Postoperative Gram-positive cocci infections were reduced in LT recipients exposing to more than two intravenous antibiotics post-LT (OR=0.269, 95% CI 0.121 to 0.598, P=0.001).
CONCLUSIONS
Gram-positive cocci infections occurring early after liver transplantation were dominated by Enterococcus faecalis infections at the abdominal/biliary tract and urinary tract. Teicoplanin, tigecycline and linezolid were anti-cocci sensitive drugs. Daptomycin and teicoplanin were equally effective in preventing cocci infections due to Gram-positive cocci. Patients with high preoperative MELD score and massive intraoperative red blood cell transfusion were more likely to suffer Gram-positive cocci infection after surgery. Postoperative Gram-positive cocci infections were reduced in recipients exposing to more than two intravenous antibiotics post-LT.
Humans
;
Daptomycin/therapeutic use*
;
Linezolid/therapeutic use*
;
Teicoplanin/therapeutic use*
;
Gram-Positive Cocci
;
Liver Transplantation/adverse effects*
;
Tigecycline/therapeutic use*
;
End Stage Liver Disease/drug therapy*
;
Gram-Positive Bacterial Infections/microbiology*
;
Severity of Illness Index
;
Anti-Bacterial Agents/pharmacology*
;
Vancomycin/therapeutic use*
;
Microbial Sensitivity Tests
10.Dichloroacetic acid and rapamycin synergistically inhibit tumor progression.
Huan CHEN ; Kunming LIANG ; Cong HOU ; Hai-Long PIAO
Journal of Zhejiang University. Science. B 2023;24(5):397-405
Mammalian target of rapamycin (mTOR) controls cellular anabolism, and mTOR signaling is hyperactive in most cancer cells. As a result, inhibition of mTOR signaling benefits cancer patients. Rapamycin is a US Food and Drug Administration (FDA)-approved drug, a specific mTOR complex 1 (mTORC1) inhibitor, for the treatment of several different types of cancer. However, rapamycin is reported to inhibit cancer growth rather than induce apoptosis. Pyruvate dehydrogenase complex (PDHc) is the gatekeeper for mitochondrial pyruvate oxidation. PDHc inactivation has been observed in a number of cancer cells, and this alteration protects cancer cells from senescence and nicotinamide adenine dinucleotide (NAD+) exhaustion. In this paper, we describe our finding that rapamycin treatment promotes pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1) phosphorylation and leads to PDHc inactivation dependent on mTOR signaling inhibition in cells. This inactivation reduces the sensitivity of cancer cells' response to rapamycin. As a result, rebooting PDHc activity with dichloroacetic acid (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, promotes cancer cells' susceptibility to rapamycin treatment in vitro and in vivo.
Humans
;
Sirolimus/pharmacology*
;
Dichloroacetic Acid/pharmacology*
;
Pyruvate Dehydrogenase Complex
;
TOR Serine-Threonine Kinases
;
Mechanistic Target of Rapamycin Complex 1
;
Neoplasms/drug therapy*

Result Analysis
Print
Save
E-mail