1.Ectopic expression of hemoglobin subunits enhances the in vitro cytotoxicity of CAR-T cells against tumor cells under hypoxic conditions
YANG Jianxun1,2 ; ZHENG Rui3 ; LIANG Sixin3 ; PAN Jie4 ; LI Yanlong5 ; ZHAI Chenxi5 ; ZHAO Xiaojuan2 ; WANG Pengju3 ; DONG Hao4 ; YAN Bo2 ; SUN Zhihong1 ; YANG Angang3
Chinese Journal of Cancer Biotherapy 2026;33(3):233-242
[摘 要] 目的:探讨异位表达血红蛋白亚基(HBA/HBB)对缺氧条件下嵌合抗原受体T细胞(CAR-T细胞)功能障碍的改善作用及其对肿瘤细胞的杀伤效应。方法:全基因合成技术合成靶向HER2的CAR序列,构建共表达HBA或HBB的CAR慢病毒载体,包装慢病毒后感染人原代T淋巴细胞,制备异位表达HBA/HBB的CAR-T细胞,命名为HBA CAR-T和HBB CAR-T。采用缺氧探针检测小鼠实体瘤缺氧状态。通过流式细胞术检测瘤内CAR-T细胞占比、异位表达血红蛋白亚基的CAR-T细胞阳性率及CAR-T细胞的活性氧、凋亡水平。WB法检测HBA CAR-T和HBB CAR-T内相关血红蛋白亚基表达情况,采用细胞计数板计数检测细胞增殖水平,通过萤光素酶报告基因法检测CAR-T细胞对肿瘤细胞的杀伤能力,qPCR检测CAR-T细胞中缺氧诱导因子-1α(HIF-1α)表达水平,利用MitoXpress Intra试剂盒检测CAR-T细胞内氧气含量。结果:不同细胞构建的实体瘤模型均存在明显缺氧情况,且CAR-T细胞浸润水平与缺氧程度呈显著负相关(P < 0.000 1)。HBA CAR-T与HBB CAR-T构建成功(阳性率 > 60%),相应血红蛋白亚基可稳定表达。缺氧环境下HBA CAR-T和HBB CAR-T的ROS水平、凋亡水平显著下降,增殖、对肿瘤细胞的体外杀伤能力显著强于传统CAR-T细胞(均P < 0.05)。HBA CAR-T与HBB CAR-T内HIF-1α表达降低(均P < 0.001),且缺氧程度显著降低(均P < 0.001)。结论:异位表达血红蛋白亚基可改善缺氧条件下CAR-T细胞功能障碍并增强其对肿瘤细胞的体外杀伤作用。
2.Role of Innate Trained Immunity in Diseases
Chuang CHENG ; Yue-Qing WANG ; Xiao-Qin MU ; Xi ZHENG ; Jing HE ; Jun WANG ; Chao TAN ; Xiao-Wen LIU ; Li-Li ZOU
Progress in Biochemistry and Biophysics 2025;52(1):119-132
The innate immune system can be boosted in response to subsequent triggers by pre-exposure to microbes or microbial products, known as “trained immunity”. Compared to classical immune memory, innate trained immunity has several different features. Firstly, the molecules involved in trained immunity differ from those involved in classical immune memory. Innate trained immunity mainly involves innate immune cells (e.g., myeloid immune cells, natural killer cells, innate lymphoid cells) and their effector molecules (e.g., pattern recognition receptor (PRR), various cytokines), as well as some kinds of non-immune cells (e.g., microglial cells). Secondly, the increased responsiveness to secondary stimuli during innate trained immunity is not specific to a particular pathogen, but influences epigenetic reprogramming in the cell through signaling pathways, leading to the sustained changes in genes transcriptional process, which ultimately affects cellular physiology without permanent genetic changes (e.g., mutations or recombination). Finally, innate trained immunity relies on an altered functional state of innate immune cells that could persist for weeks to months after initial stimulus removal. An appropriate inducer could induce trained immunity in innate lymphocytes, such as exogenous stimulants (including vaccines) and endogenous stimulants, which was firstly discovered in bone marrow derived immune cells. However, mature bone marrow derived immune cells are short-lived cells, that may not be able to transmit memory phenotypes to their offspring and provide long-term protection. Therefore, trained immunity is more likely to be relied on long-lived cells, such as epithelial stem cells, mesenchymal stromal cells and non-immune cells such as fibroblasts. Epigenetic reprogramming is one of the key molecular mechanisms that induces trained immunity, including DNA modifications, non-coding RNAs, histone modifications and chromatin remodeling. In addition to epigenetic reprogramming, different cellular metabolic pathways are involved in the regulation of innate trained immunity, including aerobic glycolysis, glutamine catabolism, cholesterol metabolism and fatty acid synthesis, through a series of intracellular cascade responses triggered by the recognition of PRR specific ligands. In the view of evolutionary, trained immunity is beneficial in enhancing protection against secondary infections with an induction in the evolutionary protective process against infections. Therefore, innate trained immunity plays an important role in therapy against diseases such as tumors and infections, which has signature therapeutic effects in these diseases. In organ transplantation, trained immunity has been associated with acute rejection, which prolongs the survival of allografts. However, trained immunity is not always protective but pathological in some cases, and dysregulated trained immunity contributes to the development of inflammatory and autoimmune diseases. Trained immunity provides a novel form of immune memory, but when inappropriately activated, may lead to an attack on tissues, causing autoinflammation. In autoimmune diseases such as rheumatoid arthritis and atherosclerosis, trained immunity may lead to enhance inflammation and tissue lesion in diseased regions. In Alzheimer’s disease and Parkinson’s disease, trained immunity may lead to over-activation of microglial cells, triggering neuroinflammation even nerve injury. This paper summarizes the basis and mechanisms of innate trained immunity, including the different cell types involved, the impacts on diseases and the effects as a therapeutic strategy to provide novel ideas for different diseases.
3.Haematococcus pluvialis alleviates bleomycin-induced pulmonary fibrosis in mice by inhibiting transformation of lung fibroblasts into myofibroblast
Xiao ZHANG ; Jingzhou MAN ; Yong ZHANG ; YunJian ZHENG ; Heping WANG ; Yijun YUAN ; Xi XIE
Journal of Southern Medical University 2025;45(8):1672-1681
Objective To investigate the effect of Haematococcus pluvialis(HP)on bleomycin(BLM)-induced pulmonary fibrosis in mice and on TGF-β1-induced human fetal lung fibroblasts(HFL1).Methods Thirty male C57BL/6 mice were randomly divided into control group,BLM-induced pulmonary fibrosis model group,low-and high-dose HP treatment groups(3 and 21 mg/kg,respectively),and 300 mg/kg pirfenidone(positive control)group.The effects of drug treatment for 21 days were assessed by examining respiratory function,lung histopathology,and expression of fibrosis markers in the lung tissues of the mouse models.In TGF-β1-induced HFL1 cell cultures,the effects of treatment with 120,180 and 240 μg/mL HP or 1.85 μg/mL pirfenidone for 48 h on expression levels of fibrosis markers were evaluated.Transcriptome analysis was carried out using the control cells and cells treated with TGF-β1 and 240 μg/mL HP.Results HP obviously alleviated BLM-induced lung function damage and fibrotic changes in mice,evidenced by improved respiratory function,lung tissue morphology and structure,inflammatory infiltration,and collagen deposition and reduced expressions of fibrotic proteins.HP at the high dose produced similar effect to PFD.In TGF-β1-induced HFL1 cells,treatment with 240 μg/mL HP significantly reduced the mRNA and protein expression levels of α-SMA and FN.Transcriptome analysis revealed that multiple key genes and pathways mediated the protective effect of HP against pulmonary fibrosis.Conclusion HP alleviates pulmonary fibrosis in both the mouse model and cell model,possibly as the result of the synergistic effects of its multiple active components.
4.131I whole-body scanning and 131I-SPECT/CT for evaluating differentiated thyroid cancer after operation and initial radioactive iodine treatment
Huan XI ; Lin LIN ; Rong FAN ; Ke YANG ; Zhengmao WEI ; Yiqing ZHENG ; Xuejuan WANG ; Rong ZHENG
Chinese Journal of Medical Imaging Technology 2025;41(1):65-69
Objective To comparatively observe the value of 131I whole-body scanning(WBS)and 131I-SPECT/CT for evaluating residual thyroid tissue,lymph node and distant metastasis,as well as risk of recurrence of differentiated thyroid cancer(DTC)after surgical resection and initial radioactive iodine(RAI)treatment.Methods Totally 367 DTC patients who underwent initial RAI treatment after surgical resection and then 131I-WBS and 131I SPECT/CT scanning were retrospectively collected.131I-WBS and 131I SPECT/CT were compared for identifying residual thyroid,lymph node and distant metastases.According to follow-up results,the risk of DTC recurrence was evaluated based on 131I-WBS and 131I-SPECT/CT,respectively.Results Residual thyroid was detected in 353 cases and suspected in 3 cases with 131 I-WBS,which was diagnosed in 349 cases with 131I-SPECT/CT,and no significant difference was found between 2 methods(P=0.289).131I-WBS detected 36 cases with and suspected 67 cases with lymph node metastases,312 without distant metastases,while 131I-SPECT/CT diagnosed lymph node metastases in 52 cases;131I-WBS detected 20 cases with and suspected 35 cases with distant metastases,while 131I-SPECT/CT diagnosed 60 cases with distant metastases but could not diagnose in 3 cases,304 without distant metastases.The detection rate of 131I-SPECT/CT for lymph node and distant metastasis were both higher than that of 131I-WBS(P=0.018,P<0.001).During follow-up period,there were 94 cases with low risk,155 with medium risk and 118 with high risk of DTC recurrence according to 131I-SPECT/CT,while 116 cases of low risk,137 of medium risk and 114 of high risk based on 131I-SPECT/CT,and the evaluating results were different between 2 methods in 40 cases(40/367,10.90%).Conclusion Compared with 131I-WBS,131I-SPECT/CT had better clinical value for evaluating lymph node and distant metastases and assessing recurrence risk of DTC after initial RAI treatment.
5.Establishment of a rat model of comorbid chronic inflammatory pain and depression using different doses of complete Freund's adjuvant
Tian WANG ; Pu YANG ; Xi ZHANG ; Xin LI ; Wenjing HUANG ; Guangmei ZHENG ; Xinyu HUANG ; Zhiyi XU ; Ying HUANG ; Lili YIN ; Shengyong SU
Acta Laboratorium Animalis Scientia Sinica 2025;33(5):633-643
Objective To compare the success rate and stability of rat models of comorbid chronic pain and depression induced by different doses of complete Freund's adjuvant(CFA).Methods Sixty SD rats were divided randomly into a control group,low-dose CFA group(CFA-L),and high-dose CFA group(CFA-H)(n=20 rats per group).Rats in the CFA-L and CFA-H groups were injected with 50 and 100 μL CFA,respectively,and rats in the control group were injected with 0.9%sodium chloride solution.The general state,body weight,mechanical withdrawal threshold(MWT),and thermal withdrawal latency(TWL)were observed at 0,7,14,21,and 28 days after modeling.Depressive behavior was evaluated using the open field test(OFT),forced swim test(FST),and tail suspension test(TST).Glutamate(Glu)and γ-aminobutyric acid(GABA)levels in the anterior cingulate cortex were detected by enzyme-linked immunosorbent assay.Brain-derived neurotrophic factor(BDNF)expression in the anterior cingulate cortex was detected by immunohistochemistry,and pathological changes in the anterior cingulate cortex were observed by HE staining.Results(1)Regarding the general condition of the rats,the left ankle joint and toes were obviously red and swollen in the CFA-L and CFA-H groups on the 7th day after modeling,and the swelling was more severe in the CFA-H group.The redness and swelling of the left hind foot and ankle joint and toes gradually recovered in the CFA-L group on days 14,21,and 28 after modeling,but were still obvious in the CFA-H group,and the water and food intake decreased.(2)The body mass was significantly lower in rats in the CFA-H group compared with those in the blank and CFA-L groups on days 14,21,and 28 after modeling(P<0.05,P<0.05).(3)Regarding pain-related behavior,the MWT and TWL were significantly decreased in the CFA-L and CFA-H groups on the 7th and 14th days after modeling,compared with the control group(P<0.05,P<0.05).On day 21 after modeling,MWT was significantly lower in the CFA-H group than in the blank and CFA-L groups(P<0.05,P<0.05),and TWL was significantly lower in the CFA-L and CFA-H groups than in the blank group(P<0.05,P<0.05).On day 28 after modeling,MWT and TWL were significantly lower in the CFA-H group than in the blank and CFA-L groups(P<0.05,P<0.05).(4)In terms of depression-related behaviors,the total OFT movement distance was significantly lower in the CFA-H group than in the blank and CFA-L groups on day 7 after modeling(P<0.05,P<0.05).The total OFT distance and central dwell time were significantly lower in the CFA-H group than in the blank and CFA-L groups on days 14,21,and 28 after modeling(P<0.05,P<0.05),and the result in the FST and TST were significantly higher than in the blank and CFA-L groups(P<0.05,P<0.05).(5)Glu,GABA,and BDNF expression levels were significantly higher in the CFA-H group than in the blank and CFA-L groups(P<0.05,P<0.05),while GABA,Glu/GABA,and BDNF levels were significantly lower in the CFA-H group than in the blank and CFA-L groups(P<0.05,P<0.05,P<0.05).(6)The CFA-L group showed less damage in the anterior cingulate cortex,more pyramidal cells,more arranged cells,clear nucleoli,and a small number of cells with karyokynesis and deep staining.Compared with the CFA-L group,rats in the CFA-H group showed a disordered cell arrangement in the injured area of the anterior cingulate cortex,a large number of pyknotic and hyperchromatic neurons,significantly fewer or absent pyramidal cells,and vacuoles,red blood cells,and neurofibrillary tangles in the interstitial space.Conclusions Injection of CFA 100 μL can be used to establish a rat model of chronic inflammatory pain and depression,showing hyperalgesia,depression-like behavioral changes,changes in levels of Glu,GABA,and BDNF in the anterior cingulate cortex,and pathological changes in the anterior cingulate cortex,consistent with the pathophysiological characteristics of chronic pain and depression.
6.Epidemiological investigation and analysis of occupational injuries of workers in metallurgical and shipbuilding and repairing industry
Xi LUO ; Zepeng LI ; Yingyin ZHANG ; Dan WANG ; Weijiang HU ; Jinnan ZHENG ; Shibiao SU
Chinese Journal of Industrial Hygiene and Occupational Diseases 2025;43(3):201-205
Objective:To understand the occupational injury situation of front-line workers in metallurgical and shipbuilding and repairing industry, and explore the risk factors of occupational injury.Methods:From September 2023 to March 2024, using cluster sampling method, front-line workers from 2 metallurgical enterprises in Shaoguan and Jinan City and 2 shipbuilding and repairing enterprises in Jiangmen and Shenzhen City were selected as the investigation objects. 6248 questionnaires were distributed and collected, and 6178 were effective questionnaires, with a effective recovery rate of 98.88%. The basic information, living habits, working system, protection and occupational injury of workers were investigated, and the data of occupational injury in factories was collected. The types, jobs and main causes of occupational injuries in different industries were analyzed, and the influencing factors of occupational injuries were analyzed by univariate and multi-factor logistic regression.Results:The incidence of occupational injury was 3.13% (128/4086) in metallurgical industry and 4.02% (84/2092) in shipbuilding and repairing industry. The top three occupational injuries in the metallurgical industry were furnace worker (17.19%, 22/128), steel rolling worker (14.84%, 19/128), maintenance worker (10.16%, 13/128), and the top three injury types were mechanical injury (24.22%, 31/128), height fall (20.31%, 26/128) and object strikes (17.97%, 23/128). The top three occupational injuries in shipbuilding and repairing industry were welder (20.24%, 17/84), riveter (9.52%, 8/84) and crane (8.33%, 7/84). The top three injury types were hit by objects (34.52%, 29/84), hit by falling objects (22.62%, 19/84), and lifting injury (20.24%, 17/84). The injuries of workers in metallurgical industry and shipbuilding and repairing industry were mainly fractures, accounting for 32.03% (41/128) and 60.71% (51/84), respectively. The incidence of occupational injury was higher in males, with sleep disorder, high temperature exposure and chemical toxicity exposure ( P<0.05). There were significant differences in age, smoking degree, working age and emotional state between workers with occupational injury and those without occupational injury ( P<0.05). Multivariate analysis showed that male, age above 50 years old, moderate smoking, working years of 5-9 years, mild anxiety, poor health status and high temperature exposure were risk factors for occupational injury ( OR=25.57, 3.72, 14.27, 2.09, 1.50, 4.36, 0.66, P<0.05) . Conclusion:The incidence of occupational injury is higher in shipbuilding and repairing industry, and fracture is the main type of occupational injury. The occurrence of occupational injury is affected by gender, age, smoking, working age, emotional state, health status and high temperature exposure.
7.Establishment and evaluation of Pseudomonas aeruginosa-induced sepsis model in mice
Wei LIU ; Jingyi WANG ; Xi ZHENG ; Yue HAN ; Wenxiong LI ; Jin ZHANG
Journal of Capital Medical University 2025;46(2):324-332
Objective To establish a reliable Pseudomonas aeruginosa(PA)-induced sepsis model,providing an effective experimental method for investigating the pathogenicity,antibiotic resistance mechanism and infection-related inflammatory pathways of PA.Methods PA ATCC 27853 was selected as experimental strain.Different concentrations of bacterial suspension were applied to the surface of erector spinae muscle in mice.Echocardiography was performed 24 h after infection to examine cardiac function.Heart,lung,kidney tissue and blood samples were collected.Serum creatinine(Cr),blood urea nitrogen(BUN),inflammatory factors,and cardiac troponin Ⅰ(CTNI)were detected.The pathological changes in the heart,lung,and kidney tissues were observed.Results The survival rates of the 107 CFU/mL group,108 CFU/mL,109 CFU/mL,and 1010 CFU/mL groups were 100%,93.3%,73.3%,and 26.7%,respectively.The concentration of interleukin-6(IL-6)in the PA-infected group was significantly higher than that in the non-infected group.The concentration of tumor necrosis factor-α(TNF-α)in 108 CFU/mL group and 109 CFU/mL group were significantly higher than that in the non-infected group.The left ventricular ejection fraction(LVEF)of 108 CFU/mL and 109 CFU/mL groups decreased significantly compared to the non-infected group,and the CTNI level increased significantly in infected group compared to the non-infected group.Compared with the non-infected group,only the 109 CFU/mL group showed significant statistical differences in Cr and BUN levels,while no significant differences were observed in the other PA-infected groups.The results of histopathology showed that the heart,lung,and kidney tissues of mice in the 109 CFU/mL group were significantly infiltrated by inflammatory cells,with obvious edema of tissue cells,disordered structural arrangement,thickening of alveolar septa,and renal interstitial stenosis.Conclusion The experiment successfully established a sepsis model induced by PA with a bacterial concentration of 109 CFU/mL,which is stable and reliable,and can provide a model basis for exploring sepsis and PA infection diseases.
8.Inhibition of excessive inflammatory response of macrophages by Ebselen against acute Escherichia coli infection
Xiao-wen LIU ; Xiao-qin MOU ; Chuang CHENG ; Shuang-shuang GONG ; Hao-ran ZHANG ; Jing HE ; Xi ZHENG ; Jun WANG ; Yue-qing WANG ; Li-li ZOU
Chinese Pharmacological Bulletin 2025;41(7):1346-1353
Aim To investigate the pharmacological mechanism of Ebselenin(Ebselen,EbSe)in the treat-ment of Escherichia coli(E.coli)infection,which had no significant inhibitory effect on Gram-negative bacte-ria,based on previous studies.Methods After EbSe intervention in E.coli infected Raw264.7 cells,the via-bility of Raw264.7 cells was determined by CCK-8 method,the morphology and structure of Raw264.7 cells were observed by electron microscope,and the in-tracellular bacterial load of Raw264.7 cells was calcu-lated by coated plate method.Polarization status of peritoneal macrophages,Raw264.7 intracellular NO and ROS content and intracellular HO-1 expression in Raw264.7 and E.coli acutely infected mice after E.co-li infection by flow cytometry.qPCR was used to detect the expression of related mRNAs in Raw264.7 cells.qPCR was used to detect the intracellular GSH content in Raw264.7 cells by spectrophotometric assay,and the state of cytoskeletal proteins was observed by immuno-fluorescence.Western blot assay was performed to de-tect the intracellular Txnrd1 expression level.Results Microtiter method,CCK-8,and electron microscopy observations showed that EbSe had no effect on the growth of E.coli and Raw264.7 cells in vitro.The re-sults of smear plate counting showed that EbSe reduced the intracellular bacterial load of Raw264.7 in the in-fected group.Flow cytometry results showed that EbSe upregulated the number of M2-type macrophages.The EbSe-treated infected group had reduced intracellular NO and ROS levels and increased GSH levels.The qPCR results showed that the expression of IL-6,IL-1β,and iNOS was decreased,and the expression of HO-1,Txnrd1,and Glut1 was increased in DHB4-in-fected Raw264.7 cells after EbSe treatment.Cytoskel-etal staining showed that the morphology of the EbSe-treated infected cells was similar to that of oxPAPC-in-duced cells.Western blot results showed the expres-sion of Txnrd1 protein in EbSe-treated infected cells in-creased.Conclusion EbSe exerts anti-E.coli acute infection effect by regulating macrophage polarization and inhibiting macrophage excessive inflammatory state.
9.Impact of ischemia time and storage periods on RNA quality of fresh-frozen breast cancer and esophageal cancer tissue samples in biobank
Yang-si ZHENG ; Xuan-hao LIN ; Fan LI ; Kun-sheng XIAO ; Xi-feng CHEN ; Chun-peng LIU ; Pei-xiu YAO ; Shao-hong WANG
Fudan University Journal of Medical Sciences 2025;52(3):437-445
Objective To investigate the effects of ischemia time and storage periods on RNA quality in fresh-frozen breast cancer(BC)and esophageal cancer(EC)tissue samples in order to establish evidence-based protocols for biobank sample management.Methods The tumor(T)and paired normal(N)tissue samples from 6 cases of BC and 6 cases of EC were collected and cryopreserved in Biobank,Shantou Central Hospital.Mirror paraffin-embedded tissues were simultaneously prepared into sections for morphological analysis.The samples were divided into two groups of<15 min and 15-30 min according to ischemia time,and RNA quality was analyzed at 4 storage periods of 8-10 months(T1),14-16 months(T2),26-28 months(T3)and 38-40 months(T4).Results In 96 analyzed samples,93.8%(90/96)exhibited high quality(RIN≥6),with 89.6%(43/48)in BC and 97.9%(47/48)in EC.Significant differences in RIN were observed between BC group and EC group(8.050 vs.8.600,P=0.009).In EC group,RIN value was significantly negatively correlated with RNA yield(P<0.001).Moreover,RIN values of tumor-normal pairs exhibited markedly significant differences(7.550 vs.9.000,P<0.001).In contrast,no significant difference was detected in BC group(8.200 vs.7.700,P=0.348).Statistical analysis showed that RIN value was positively correlated with 28S/18S(P<0.001),but had no correlation with tumor content(P=0.676)and necrotic content(P=0.055).Neither ischemia time(<15 min vs.15-30 min:8.200 vs.8.300,P=0.932)nor storage periods(T1-T4:8.400,7.700,8.450,8.600,P=0.163)compromised RNA quality.Conclusion Organ origin and tissue type could influence RNA quality of fresh-frozen tissue samples.However,limited ischemia time(≤30 min)and long-term storage period(38-40 months)do not adversely affect RNA quality in fresh-frozen breast cancer and esophageal cancer tissue samples.
10.Preparation of nanosized hypoxia-inducible factor 1α inhibitor and its application in reversing chemoresistance in colorectal cancer cells
Chuanhao ZHENG ; Ruijue DAN ; Xi XI ; Wang YING ; Qiang LUO
Journal of Army Medical University 2025;47(11):1177-1189
Objective To modify YC-1,an inhibitor of hypoxia-inducible factor-1α(HIF-1α)into nanoparticles and explore its effect on reversing chemoresistance of colorectal cancer cells.Methods Nano-inhibitor mPEG350-YC-1(MYC-1)was prepared by the carboxyl condensation reaction of the active functional group hydroxyl(-OH)in the YC-1 molecule with methoxy polyethylene glycol carboxylic acid,and was verified by 1H nuclear magnetic resonance(1H-NMR).Its morphology was analyzed by transmission electron microscope(TEM),and its particle size distribution was analyzed by dynamic light scattering(DLS).By interacting FITC-labeled MYC-1(FYC-1)with HCT15 cells,the uptake ability of FYC-1 by the cells was observed using laser confocal microscopy.The cytotoxicity of MYC-1 was measured with CCK-8 assay.The sensitization effect of MYC-1 on the chemotherapy drug 5-Fu was detected through toxicity tests of resistant HCT15 cells(resistant HCT15,R-HCT15)and live/dead cell staining.The mechanism of MYC-1 reversing drug resistance was determined with immunofluorescence staining of HIF-1α and western blotting.Finally,a subcutaneous transplanted tumor model of R-HCT15 cells was constructed.The tumor bearing mice were randomly divided into PBS,5-Fu,MYC-1,and MYF groups,with 3 mice in each group.The tumor volume and weight were observed after treatment in each group to evaluate the ability of MYC-1 to reverse 5-Fu resistance in colorectal cancer.Results The nano-inhibitor MYC-1 was successfully prepared.TEM and DLS showed that MYC-1 could self-assemble into nanoparticles with a diameter of approximately 19.96±2.97 nm in aqueous solution.FYC-1 was also successfully prepared.When FYC-1 was interacted with HCT15 cells,FYC-1 could be better taken up by the cells,indicating that the amphiphilic MYC-1 could be better endocytosed into the cells to exert its function.When MYC-1 and 5-Fu acted in combination in colon cancer R-HCT15 cells,the resistance index(RI)was decreased from 7.99 to 1.55,and the relative reversal rate(RRR)of RI was 80.6%.Live(green)/dead(red)cell staining revealed that MYC-1 increased the toxicity of 5-Fu to R-HCT15 cells.Immunofluorescence staining(P<0.01)and Western blotting indicated that MYC-1 effectively inhibited the intracellular expression of HIF-1α.The combined action of MYC-1 and 5-Fu on mice with R-HCT15 subcutaneous transplanted tumors had the best therapeutic effect when compared with PBS(P<0.001),5-Fu(P<0.01),and MYC-1(P<0.01).Immunofluorescence staining of HIF-1α in tumor tissues displayed that the expression of HIF-1α was decreased in the MYC-1 and MYF groups.HE staining showed that there was no obvious damage to the important organs in each treatment group.Conclusion Nano-inhibitor MYC-1 can reverse the drug resistance of colorectal cancer to 5-Fu chemotherapy by reducing the expression of HIF-1α protein in colorectal cancer cells,thereby effectively improving the therapeutic effect of 5-Fu.

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