Microbial contamination of food contact surfaces constitutes a significant vector for foodborne disease transmission, presenting substantial public health risks. Conventional surface sterilization methods, however, are often limited by suboptimal efficacy, poor stability, or the propensity to foster antimicrobial resistance. Consequently, the development of novel and highly effective antibacterial strategies remains imperative. In this study, an innovative ZIF-8@Apt composite antibacterial system by integrating Zeolitic Imidazolate Framework-8 (ZIF-8) with a tailored aptamer (Apt) specifically targeting the beta and beta' subunits of RNA polymerase was developed. The system works via a dual mechanism: ZIF-8 releases Zn2+ and induces reactive oxygen species (ROS) production to disrupt bacterial membrane integrity for aptamer entry, and the internalized aptamer binds to RNA polymerase to block transcription of critical bacterial genes by interfering with its active site. This synergistic approach achieves potent antibacterial effects, with minimum inhibitory concentrations (MICs) of 512 mu g & sdot;mL- 1 and 128 mu g & sdot;mL- 1 against Cronobacter sakazakii and Staphylococcus aureus, respectively. Furthermore, ZIF-8@Apt demonstrates remarkable biofilm inhibition and dispersal capabilities. Practical evaluation on food contact surfaces confirms that ZIF-8@Apt achieves rapid bactericidal activity within 20-30 min and sustains prolonged antibacterial efficacy for at least 2 h post-application. These findings underscore the potential of ZIF8@Apt as a broad-spectrum antibacterial solution for food safety applications.
It has been reported that PL2L60 proteins, a product of PIWIL2 gene which might be activated by an intragenic promoter, could mediate a common pathway specifically for tumorigenesis. In the present study, it was further identified by using western blot assay that the PL2L60 proteins could be degraded in cancer cells through a mechanism of selective autophagy in response to oxidative stress. The PL2L60 was downregulated in various types of cancer cells under the hypoxic condition independently of HIF-1 alpha, resulting in apoptosis of cancer cells. Inhibition of autophagy by small interfering RNA targeting of either Beclin-1 (BECN1) or Atg5 resulted in restoration of PL2L60 expression in hypoxic cancer cell. The hypoxic degradation of PL2L60 was also blocked by the attenuation of the autophagosome membrane protein Atg8/microtubule-associated protein 1 light chain 3 (LC3) or autophagy cargo protein p62 expression. Surprisingly, Immunofluorescence analysis demonstrated that LC3 could be directly bound to PL2L60 and was required for the transport of PL2L60 from the nucleus to the cytoplasm for lysosomal flux under basal or activated autophagy in cancer cells. Moreover, flow cytometric analysis displayed that knocking down of PL2L60 mRNA but not PIWIL2 mRNA effectively inhibited cancer cell proliferation and promoted apoptosis of cancer cells. The similar results were obtained from in vivo tumorigenic experiment, in which PL2L60 downregulation in necroptosis areas was confirmed by immunohistochemistry. These results suggested that various cancer could be suppressed by promoting autophagy. The present study revealed a key role of autophagic degradation of PL2L60 in hypoxia-induced cancer cell death, which could be used as a novel therapeutic target of cancer.
Background Colorectal cancer (CRC) is one of the most common tumors globally and a leading cause of cancer-related death. In China, CRC is the third most common cancer type. Sauchinone is known to exhibit anti-tumor and anti-inflammatory activity, but its effects on CRC have not been investigated to-date. Objective To investigate the effects of Sauchinone on CRC development and metastasis and its underlying mechanism(s) of action. Methods SW480 and HCT116 cells were treated with a range of concentrations of Sauchinone. Cell proliferation was measured using EDU assays and flow cytometry. Results Treatment with 50 & mu;M Sauchinone decreased the expression of MMP2 and MMP9 and downregulated PD-L1 expression (PD-1/PD-L1) leading to checkpoint inhibition. Sauchinone treatment also enhanced the cytotoxicity of SW840 and HCT116 cells co-cultured with CD8(+) T cells. The overexpression of PD-L1 rescued the anti-proliferative and cytotoxic effects of Sauchinone in both types. Conclusions We show that Sauchinone suppresses CRC cell growth through the downregulation of MMP2 and MM9 expression and PD-1/PD-L1 mediated checkpoint inhibition. Collectively, these data highlight the promise of Sauchinone as a future anti-CRC therapeutic.
Salmonella spp., as one of the foodborne pathogens, is a severe threat to global public health. Rapid screening of salmonella spp. in contaminated food with low infective doses is the key to preventing food poisoning. In this study, a fast visualization method for detecting Salmonella typhimurium (S. typhimurium) was developed based on photonic PCR and AuNPs lateral-flow immunochromatography strip (LFIS). In addition, quantitative detection of target bacteria could be achieved by utilizing the photothermal effect of AuNPs, and the sensitivity could be improved by amplifying the photothermal signal. On the optimized conditions, the developed photonic PCR-LFIS assay was highly sensitive, with a detection limit as low as 19 cfu mL-1 of bacteria in pure culture after laser irradiation, and highly specific, exhibiting no cross-reaction with Salmonella enteritidis, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus. Notably, S. typhimurium could be detected in pork, egg white, and milk without pre-treatment, with the recovery rates of the three samples between 81 % and 109 %. In conclusion, the photonic PCR-LFIS assay realizes sensitive, simple, and rapid detection of S. typhimurium.
There are numerous antibodies used for cancer therapy in clinic, but they are essentially less efficacy than expected. None of them has tumor-specific and broad-spectral properties. PIWIL2-like (PL2L) protein 60 (PL2L60) is a product of alienated activation of PIWIL2 gene, and has been found to be specifically and widely expressed in various types of cancers, including hematopoietic and solid ones. Current study aims to investigate whether a monoclonal antibody (mAb) to PL2L60 has both tumor-specific and broad-spectral properties, which can be used universally to treat various types of cancers. The expression of PL2L60 protein in the cell surface and cytoplasm were determined in a panel of human and mouse tumor cell lines by flow cytometry, immunofluorescent microscopy and Western Blotting. The apoptosis and the cell cycle arrest of the tumor cells treated with mAb KAO3 were evaluated by flow cytometry. The tumorigenesis of the mAb KAO3-pretreated tumor cells was determined by tumor incidence and tumor size, and the efficacy of mAb KAO3 treatment on tumor growth in tumors-bearing mice were kinetically evaluated. Complement-dependent cytotoxicity (CDC) assay was used to determine the capacity of mAb KAO3 to kill tumor cells. Treatment of human or mouse tumor cells from hematopoietic or solid tumors with mAb KAO3 at the time of inoculation efficiently inhibited tumorigenesis in the severe combined immunodeficient (SCID) mice. Moreover, injection of mAb KAO3 into established tumors significantly inhibited their growth, and prolonged survival of the tumor-bearing mice, including lymphoma, breast cancer, lung cancer and cervical cancer. The efficacy of mAb KAO3 treatment is likely associated with its binding to PL2L60 expressed on tumor cell surface, which may lead to cancer cell death through blocking cell cycling and/or activation of complement. In conclusion, we have identified a tumor-specific mAb to PL2L60 (KAO3), which may be used potentially to treat all the types of human cancers including from both hematopoietic and solid ones.
Background : PL2L60 is a PIWIL2-like (PL2L) protein that is specifically and widely expressed in various types of hematopoietic and solid tumors. However, it is unknown whether PL2L60 is an effective target for cancer immunotherapy. The current study aimed to investigate the efficacy of an monoclonal antibody (mAb) to PL2L60 (clone KAO3;IgM isotype) in treatment of the cancers either from human or mouse. Methods : The expression of PL2L60 protein in the cell surface and cytoplasm were determined in a panel of human and mouse tumor cell lines by flow cytometry, immunofluorescent staining and Western Blotting. The apoptosis and the cell cycle arrest of the tumor cells treated with mAb KAO3 were evaluated by flow cytometry. The tumorigenesis of the mAb KAO3-pretreated tumor cells was determined by tumor incidence and tumor size, and efficacy of mAb KAO3 treatment on tumor growth in tumors-bearing mice were kinetically evaluated. Complement-dependent cytotoxicity tests were utilized to determine the mechanism of mAb KAO3 killing tumor cells. Results : Treatment of human or mouse tumor cells with mAb KAO3 at the time of inoculation efficiently inhibited their tumorigenesis in the immunodeficient mice. Moreover, injection of mAb KAO3 into established tumors significantly inhibited their growth, and prolonged survival of the tumor-bearing mice, including lymphoma, breast cancer, lung cancer and cervical cancer. The inhibitory effects of mAb KAO3 were likely associated with its binding to the PL2L60 expressed on tumor cell surface, which may induce cell apoptosis through either activation of complement or blocking cell cycling. The cell cycling was arrested at G 2 /M phase and DNA synthesis may be inhibited. Conclusion : We have identified the PL2L60 as a novel tumor-specific and broad-spectral biomarker, which is recognized by the mAb KAO3 as an efficient target for immunotherapy of both solid and hematopoietic cancers.
In some Gram-negative bacteria, ompF encodes outer membrane protein F (OmpF), which is a cation-selective porin and is responsible for the passive transport of small molecules across the outer membrane. However, there are few reports about the functions of this gene in Cronobacter sakazakii. To investigate the role of ompF in detail, an ompF disruption strain (ΔompF) and a complementation strain (cpompF) were successfully obtained. We find that OmpF can affect the ability of biofilm formation in C. sakazakii. In addition, the variations in biofilm composition of C. sakazakii were examined using Raman spectroscopy analyses caused by knocking out ompF, and the result indicated that the levels of certain biofilm components, including lipopolysaccharide (LPS), were significantly decreased in the mutant (ΔompF). Then, SDS-PAGE was used to further analyze the LPS content, and the result showed that the LPS levels were significantly reduced in the absence of ompF. Therefore, we conclude that OmpF affects biofilm formation in C. sakazakii by reducing the amount of LPS. Furthermore, the ΔompF mutant showed decreased (2.7-fold) adhesion to and invasion of HCT-8 cells. In an antibiotic susceptibility analysis, the ΔompF mutant showed significantly smaller inhibition zones than the WT, indicating that OmpF had a positive effect on the influx of antibiotics into the cells. In summary, ompF plays a positive regulatory role in the biofilm formation and adhesion/invasion, which is achieved by regulating the amount of LPS, but is a negative regulator of antibiotic resistance in C. sakazakii.
Aims: Dietary phytochemicals and diet types (e.g., the Mediterranean diet) have been shown to have anti-cancer properties. However, the effects of combined treatment with dietary phytochemicals and different diet types on primary and metastatic tumor growth have yet to be investigated. The purpose of this study is to investigate the effects of phytochemicals combined with diet types on breast cancer metastasis. Main methods: The inhibitory effects on breast cancer metastasis of three phytochemicals (allicin, hesperidin, astragalus polysaccharides) and two diet types (Mediterranean diet, restricted diet), separately or in combination, were evaluated based on: (i) detection of circulating tumor cells (CTCs) using an in vivo capture method; and (ii) primary tumor growth. Key findings: All dietary factors significantly inhibited the growth of primary tumors and metastases, with combinations showing enhancing the effects. Significance: Dietary phytochemicals and diet types should be further evaluated as adjunct therapies and lifestyle modifications in cancer patients. Furthermore, the in vivo CTC capture method allows dynamic monitoring of cancer metastasis over time, providing a useful approach to evaluating treatment effects in real-time.
为了解奶粉中阪崎克罗诺杆菌耐干燥性及多位点序列分型(multilocus sequence typing,MLST)间的关系,对实验室保存的35株阪崎克罗诺杆菌进行干燥试验,并采用MLST对所有菌株进行分子遗传学分析。经过6 d干燥试验处理,结果显示,35株阪崎克罗诺杆菌中,耐干燥能力较强的IQCC10409(1号)、IQCC10455(6号)和110609-3(31号)菌株失活率分别为63.73%、56.94%和44.43%,其中31号菌株耐干燥能力最强,它们分别属于ST73、ST73和ST23型。MLST分析表明,全部菌株共分成16个不同的序列型(sequence type,ST),其中,属于ST1型(20号、24号、27号、28号、33号)和ST4型(4号、6号、7号、9号、11号)的菌株较多,分别有5株菌。结果表明阪崎克罗诺杆菌基因多样性程度较高,而耐干燥性较强的菌株主要集中于ST73和ST4型,另外还发现,即使相同ST型的菌株,其耐干燥能力也不定相同。
通过建立一种将重组酶聚合酶恒温扩增(recombinase polymerase amplification,RPA)与乳胶微球试纸条(latex microsphere test strips,LMTS)相结合的方法,快速检测金黄色葡萄球菌。根据金黄色葡萄球菌保守区序列(nuc)设计特异性引物,经RPA扩增后用LMTS检测,确定RPA-LMTS检测金黄色葡萄球菌的灵敏度和特异性。灵敏度结果显示RPA-LMTS检测限为500 fg DNA和1.2×101 CFU/mL纯菌液;特异性结果表明与沙门氏菌、大肠杆菌O157∶H7、志贺氏菌、产气肠杆菌和单增李斯特菌无交叉反应,特异性良好;用食物样品评估RPA-LMTS检测效果,结果显示经过增菌3小时后,RPA-LMTS可检测1.2×100 CFU/mL(g)的金黄色葡萄球菌。
Locally applied radiation to the tumor is reported to stimulate systemic immune response. During radiotherapy to the abdominal cancer, spleen often receives certain dose, though as an important immune organ, little is known about the impact of splenic irradiation (SI) on systemic immune and local tumor control. Through a mice model, we found that the combination of SI with tumor irradiation (TI) helped in local control. The analysis of the tumor infiltrating leucocytes demonstrated that SI plus TI brought more T cell aggregation in the tumor microenvironment (TME), which helped in tumor control. Increased T cell infiltration may be partly due to higher expression of T cell chemokine in the TME and more expression of CXCR3 on the T cells in the spleen after SI. SI produced more IL-1β in the spleen, IL-1β stimulated the expression of CXCR3 on the T cells, and enhanced their migration ability. Taken together, radiation to the spleen combined with TI helped in local control through promoting T cell infiltration, and may be a considerable means to enhance the immunomodulatory of radiotherapy.
It is well-known that the activation status of the P53, signal transducer and activator of transcription (Stat)3 and nuclear factor (NF)‑κB signaling pathways determines the radiosensitivity of cancer cells. However, the function of these pathways in radiosensitive vs radioresistant cancer cells remains elusive. The present study demonstrated that adaptive expression of epidermal growth factor (EGF) following exposure to ionizing radiation (IR) may induce radiosensitization of pancreatic cancer (PC) cells through induction of the cyclin D1/P53/poly(ADP‑ribose) polymerase pathway. By contrast, adaptively expressed interleukin (IL)‑6 and insulin‑like growth factor (IGF)‑1 may promote radioresistance of PC cells, likely through activation of the Stat3 and NF‑κB pathways. In addition, cyclin D1 and survivin, which are specifically expressed in the G1/S and G2/M phase of the cell cycle, respectively, are mutually exclusive in radiosensitive and radioresistant PC cells, while Bcl‑2 and Bcl‑xL expression does not differ between radiosensitive and radioresistant PC cells. Therefore, adaptively expressed EGF and IL‑6/IGF‑1 may alter these pathways to promote the radiosensitivity of PC cancers. The findings of the present study highlight potential makers for the evaluation of radiosensitivity and enable the development of effective regimens for cancer radiotherapy.
Endogenous immune response participates in tumor control, and radiotherapy has immune modulatory capacity, but the role of immune modulation in the tumor microenvironment invoked by radiotherapy in radiosensitivity is poorly defined. In the present study, a radio-resistant melanoma cell line was obtained after repeated irradiation to the parental tumor in C57BL/6 mice. Radiotherapy resulted in aggregation of CD8(+) and CD3(+) T cells, and decrease of myeloid-derived suppressor cells and dendritic cells in the parental tumor, but not in the resistant tumors. CD4(+) T cells and B cells did not change significantly. The CD8(+) T cell infiltration after radiotherapy is important for tumor response, because in the nude mice and CD8(+) T cell-depleted C57BL/6 mice, the parental and resistant tumor has similar radiosensitivity. Patients with good radiation response had more CD8(+) T cells aggregation after radiotherapy. Radiotherapy resulted in robust transcription of T cell chemoattractant in the parental cells, and the expression of CCL5 was much higher. These results reveal a novel mechanism of radioresistance, tumor cells inhibit the infiltration of CD8(+) T cell after radiotherapy and become radioresistant. Increasing CD8(+) T cell infiltration after RT may be an effective way to improve tumor radiosensitivity.
As traditional edible fungi, Monascus spp. have been widely used as folk medicine, food colorants, and fermentation starters in East Asian countries for more than a thousand years. However, the presence of citrinin, which has nephrotoxic, hepatotoxic, and carcinogenic activities, raises suspicions about the safety of Monascus products. Citrinin biosynthesis in Monascus is known to occur via a polyketide pathway and a citrinin biosynthesis gene cluster, which include the characterized polyketide synthetase pksCT. A gene, orf6, encodes a protein that shows significant similarity to glyoxalase and is located between ctnE and orf1. This study analyzed orf6 function, and successfully obtained an orf6 disruption strain (Δorf6). Citrinin production was significantly greater (3.6-fold) in the Δorf6 strain than in the wild-type Monascus purpureus YY-1, and RT-PCR analysis further revealed increased expression of numerous genes of the citrinin biosynthesis gene cluster in Δorf6. Therefore, orf6 proved to be a major inhibitor, directly involved in citrinin biosynthesis. Moreover, pigment production in Δorf6 was reduced by approximately 30%, while the transcription levels of many genes involved in Monascus pigments (MPs) biosynthesis had increased. This dichotomy indicated that MPs and citrinin yields may be improved simultaneously; however, a portion of the pigments was consumed to protect the cells from oxidative damage in the Δorf6 strain. An Δorf6 revertant restored the citrinin and pigment yields to normal levels. This study makes a contribution to explore the citrinin biosynthesis pathway and provides some theoretical guidance to improving the safety of Monascus-related products.
PIWIL2-like (PL2L) protein 60 (PL2L60), a product of aberrantly activated PIWIL2 gene, is widely expressed in various types of tumors and may promote tumorigenesis. However, the mechanisms underlying the activation of expression of PL2L60 remain unknown. In this study, an intragenic promoter responsible for the activation of PL2L60 within the human PIWIL2 gene has been identified, cloned and characterized. The promoter of PL2L60 is located in the intron 10 of the host gene PIWIL2. Bioinformatic and mutagenic analysis reveals that this intragenic promoter within the sequence of 50 nucleotides contains two closely arranged cis-acting elements specific for the hepatic leukemia factor (HLF) in the positive strand and signal transducer and activator of transcription 3 (STAT3) in the negative strand. Chromatin immunoprecipitation analysis demonstrates that both the HLF and polymerase II (Pol II), a hallmark of active promoters, directly bind to the sequence, although STAT3 does not. Knockdown of HLF and STAT3 alone or both by RNA interference significantly reduced both promoter activity and the PL2L60 protein expression, although there is no additive effect. The expression of PL2L60 proteins was enhanced when host gene Piwil2 was genetically disrupted in a murine cell model. Taken together, we have identified a PL2L60-specific intragenic promoter in the host gene of PIWIL2, which is interdependently activated by HLF and STAT3 through steric interaction. This activation is dependent on cellular milieu rather than the integrity of host gene PIWIL2, highlighting a novel, important mechanism for a cancer-causing gene to be activated during tumorigenesis.
Cronobacter sakazakii is an important foodborne pathogen that causes neonatal meningitis and sepsis, with high mortality in neonates. However, very little information is available regarding the pathogenesis of C. sakazakii at the genetic level. In our previous study, a cellulose biosynthesis-related gene (bcsR) was shown to be involved in C. sakazakii adhesion/invasion into epithelial cells. In this study, the detailed functions of this gene were investigated using a gene knockout technique. A bcsR knockout mutant (ΔbcsR) of C. sakazakii ATCC BAA-894 showed decreased adhesion/invasion (3.9-fold) in human epithelial cell line HCT-8. Biofilm formation by the mutant was reduced to 50% of that exhibited by the wild-type (WT) strain. Raman spectrometry was used to detect variations in biofilm components caused by bcsR knockout, and certain components, including carotenoids, fatty acids, and amides, were significantly reduced. However, another biofilm component, cellulose, was increased in ΔbcsR, suggesting that bcsR negatively affects cellulose biosynthesis. This result was also verified via RT-PCR, which demonstrated up-regulation of five crucial cellulose synthesis genes (bcsA, B, C, E, Q) in ΔbcsR. Furthermore, the expression of other virulence or biofilm-related genes, including flagellar assembly genes (fliA, C, D) and toxicity-related genes (ompA, ompX, hfq), was studied. The expression of fliC and ompA in the ΔbcsR mutant was found to be remarkably reduced compared with that in the wild-type and the others were also affected excepted ompX. In summary, bcsR is a negative regulator of cellulose biosynthesis but positively regulates biofilm formation and the adhesion/invasion ability of C. sakazakii.
Both adaptive and acquired resistance significantly limits the efficacy of the epidermal growth factor receptor (EGFR) kinase inhibitors. However, the distinct or common mechanisms of adaptive and acquired resistance have not been fully characterized. Here, through systematic modeling of erlotinib resistance in lung cancer, we found that feedback reactivation of MAPK signaling following erlotinib treatment, which was dependent on the MET receptor, contributed to the adaptive resistance of EGFR inhibitors. Interestingly, acquired resistance to erlotinib was also associated with the MAPK pathway activation as a result of CRAF or NRAS amplification. Consequently, combined inhibition of EGFR and MAPK impeded the development of both adaptive and acquired resistance. These observations demonstrate that adaptive and acquired resistance to EGFR inhibitors can converge on the same pathway and credential cotargeting EGFR and MAPK as a promising therapeutic approach in EGFR mutant tumors.
目的 研究自然杀伤细胞(NK细胞)与自然杀伤树突状细胞(NKDCs)在免疫系统重建中的变化及相互关系.方法 利用骨髓重建小鼠模型,采用流式细胞仪分选NK细胞、树突状细胞(DCs)和NKDCs;免疫佐剂CpG体外刺激NK细胞和NKDCs,检测细胞因子IFN-γ的分泌情况.结果 在免疫系统重建过程中,骨髓或脾脏的NK细胞和NKDCs均在1周内出现升高,至第4周恢复到正常水平,提示天然免疫功能在骨髓重建过程中首先重建;其次,NK细胞和NKDCs在功能上是两群性质不同的细胞,NKDCs产生IFN-γ的能力高于NK细胞.CpG可以刺激NKDCs产生IFN-γ,但对NK细胞无相应作用.INF-γ的产生与NK细胞或NKDCs表达B220水平无关.结论 NKDCs可能在天然抗肿瘤免疫中起关键作用.
Although tumor immunotherapy has been proposed for many years,the consensus denoting it as an essential approach for fighting against cancer is reached only in recent years. Tumor immunotherapy can be categorized as active and passive ones. In order to successfully cure cancer,safe and efficient active immunotherapy is required. Dendritic cells (DCs)are not only the bridge linking innate and adaptive immunity,but also the key determinants of the quality of adaptive immunity:immunity versus immune tolerance. Therefore,the safe and efficient DC-based tumor-specific and broad-spectral tumor vaccine has an irreplaceable important position in tumor immunotherapy. Because of the high heterogeneity of DCs, the research on DC-based tumor vaccine has encountered a bottleneck. Here,we reviewed the progress in research on DC-based tumor vaccine and related problems needed to be resolved with the incorporation of our experiences.