Genomic characteristics of antimicrobial resistance and virulence factors of carbapenem-resistant Stutzerimonas nitrititolerans isolated from the clinical specimen.

BACKGROUND: Stutzerimonas nitrititolerans (S. nitrititolerans) is a rare human pathogenic bacterium and has been inadequately explored at the genomic level. Here, we report the first case of carbapenem-resistant S. nitrititolerans isolated from the peritoneal dialysis fluid of a patient with chronic renal failure. This study analyzed the genomic features, antimicrobial resistance, and virulence factors of the isolated strain through whole genome sequencing (WGS). METHODS: The bacterial isolate from the peritoneal dialysis fluid was named PDI170223, and preliminary identification was conducted through Matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS). WGS of the strain PDI170223 was performed using the Illumina platform, and a phylogenetic tree was constructed based on the 16S rRNA gene sequences. Antimicrobial susceptibility test (AST) was conducted using the TDR-200B2 automatic bacteria identification/drug sensitivity tester. RESULTS: S. nitrititolerans may emerge as a human pathogen due to its numerous virulence genes, including those encoding toxins, and those involved in flagellum and biofilm formation. The AST results revealed that the strain is multidrug- and carbapenem-resistant. The antimicrobial resistance genes of S. nitrititolerans are complex and diverse, including efflux pump genes and ß⁃lactam resistance genes. CONCLUSION: The analysis of virulence factors and antimicrobial resistance of S. nitrititolerans provides clinical insight into the pathogenicity and potential risks of this bacterium. It is crucial to explore the mechanisms through which S. nitrititolerans causes diseases and maintains its antimicrobial resistance, thereby contributing to development of effective treatment and prevention strategies.

Community-acquired pneumonia caused by Micrococcus antarcticus: a rare case report.

BACKGROUND: Micrococcus antarcticus (M. antarcticus) is an aerobic Gram-positive spherical actinobacterium that was initially isolated from Chinese Great-Wall station in Antarctica in 2000. M. antarcticus was considered to be of low pathogenicity, no previous cases of human infection by this organism have been reported. Here we describe the first report with community-acquired pneumonia (CAP) caused by M. antarcticus. CASE PRESENTATION: An 87-year-old female was presented to the Central Hospital of Wuhan in November 2023 with a chief complaint of cough, sputum production, and chest tightness for 2 weeks. Microbial culture of the patient's bronchoalveolar lavage fluid (BALF) and identification of the isolates using Matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing revealed M. antarcticus infection. Combined with clinical symptoms, laboratory and imaging examination, the patient was diagnosed with CAP. Then cefoperazone/sulbactam and levofloxacin was administrated, the patient's condition was improved and she was discharged after a week after admission, no abnormalities were detected during a 5-month follow-up. CONCLUSIONS: This case highlights that M. antarcticus, first identified from a patient with CAP, is an extremely rare pathogenic microorganism. Clinicians should be aware of its potential as a pathogen in the diagnosis and treatment of CAP.

Huaier suppresses cell viability, migration and invasion in human non-small cell lung cancer via lncRNA DLEU2/miR-212-5p/ELF3 axis.

Accumulating studies suggest that Huaier exerts anti-tumor effects through intricate mechanisms. Despite extensive research on its efficacy in lung cancer, further investigation is required to elucidate the molecular mechanism of Huaier. The involvement of long noncoding RNAs (lncRNAs) in the anti-lung cancer effects of Huaier remains unknown. In this study, we found Huaier suppressed cell viability, migration and invasion in non-small cell lung cancer (NSCLC) cells. LncRNA sequencing analysis revealed Deleted in lymphocytic leukemia 2 (DLEU2) to be significantly downregulated in Huaier-treated NSCLC cells. Furthermore, DLEU2 silencing was observed to suppress NSCLC progression, while DLEU2 overexpression attenuated the anti-tumor effects of Huaier in NSCLC, thereby promoting cell viability, migration and invasion of NSCLC. The ceRNA role of DLEU2 had been demonstrated in NSCLC, which directly interacted with miR-212-5p to rescue the repression of E74 Like ETS Transcription Factor 3 (ELF3) by this microRNA. Additionally, Huaier was found to regulate the expression of miR-212-5p and ELF3. Functionally, miR-212-5p inhibitor or ELF3 overexpression reversed the effects of DLEU2 silencing or Huaier treatment, resulting in increased colony formation, migration and invasion in NSCLC. Taken together, these results illuminate the mechanism underlying Huaier's anti-tumor effects via the DLEU2/miR-212-5p/ELF3 signaling pathway, which offers novel insights into the anti-tumor effects of Huaier and constitutes a promising therapeutic target for the treatment in NSCLC.

MYD88 L265P elicits mutation-specific ubiquitination to drive NF-κB activation and lymphomagenesis.

Myeloid differentiation primary response protein 88 (MYD88) is a critical universal adapter that transduces signaling from Toll-like and interleukin receptors to downstream nuclear factor-κB (NF-κB). MYD88L265P (leucine changed to proline at position 265) is a gain-of-function mutation that occurs frequently in B-cell malignancies such as Waldenstrom macroglobulinemia. In this study, E3 ligase RING finger protein family 138 (RNF138) catalyzed K63-linked nonproteolytic polyubiquitination of MYD88L265P, resulting in enhanced recruitment of interleukin-1 receptor-associated kinases and elevated NF-κB activation. However, RNF138 had little effect on wild-type MYD88 (MYD88WT). With either RNF138 knockdown or mutation on MYD88 ubiquitination sites, MYD88L265P did not constitutively activate NF-κB. A20, a negative regulator of NF-κB signaling, mediated K48-linked polyubiquitination of RNF138 for proteasomal degradation. Depletion of A20 further augmented MYD88L265P-mediated NF-κB activation and lymphoma growth. Furthermore, A20 expression correlated negatively with RNF138 expression and NF-κB activation in lymphomas with MYD88L265P and in those without. Strikingly, RNF138 expression correlated positively with NF-κB activation in lymphomas with MYD88L265P, but not in those without it. Our study revealed a novel mutation-specific biochemical reaction that drives B-cell oncogenesis, providing a therapeutic opportunity for targeting oncogenic MYD88L265P, while sparing MYD88WT, which is critical to innate immunity.

Association of elevated mid-pregnancy maternal plasma ferritin concentrations and triglyceride concentrations with the risk of gestational diabetes mellitus: A prospective cohort study.

OBJECTIVE: Ferritin levels are well known to be associated with gestational diabetes mellitus (GDM). However, the association of the combination of ferritin and triglyceride (TG) levels in early mid-pregnancy with GDM has not been studied in depth. We investigated the independent and combined relationships of plasma ferritin and TG concentrations with the risk of GDM as well as the mediation effect of TG on ferritin. METHODS: We analysed 2071 pregnant women from the Tongji Maternal and Child Health Cohort who had their plasma ferritin and TG concentrations measured at 11-20 weeks of gestation. Associations between ferritin and TG concentrations and GDM risk were estimated using multivariable logistic regression models. Youden's index was calculated to find the cut-off values of ferritin and TG by ROC curve analysis. The mediation effect of the TG concentration on the ferritin level with GDM risk was explored by a mediation analysis. RESULTS: A total of 264 (12.3%) participants developed GDM. The median and IQR of ferritin was 53.9 (30.5-92.7) ng/mL. After adjusting for potential confounders, the relative risks (RRs) and 95% confidence intervals of GDM were 2.19 (1.42, 3.39) for ferritin and 2.02 (1.37, 2.97) for TG. The adjusted RR for combination was 2.40 (1.62, 3.55). Moreover, we found that the TG concentration mediated 15.0% of the total effect of the ferritin concentration on the risk of GDM. CONCLUSIONS: Women with a combination of both high plasma ferritin (˃55.7 ng/mL) and high TG (˃1.9 mmoL/L) were at the highest risk of GDM. Additionally, we have revealed for the first time that an elevated maternal TG concentration in early pregnancy mediates the relationship between ferritin concentration and GDM risk. TRIAL REGISTRATION: This trial is registered at https://ClinicalTrials.gov as NCT03099837.

Tat-NTS Suppresses the Proliferation, Migration and Invasion of Glioblastoma Cells by Inhibiting Annexin-A1 Nuclear Translocation.

Prevention of the nuclear translocation of ANXA1 with Tat-NTS was recently reported to alleviate neuronal injury and protect against cerebral stroke. However, the role that Tat-NTS plays in the occurrence and development of gliomas still needs to be elucidated. Therefore, human glioblastoma (GB) cells were treated with various concentrations of Tat-NTS for 24 h, and cell proliferation, migration and invasion were assessed with CCK-8 and Transwell assays. The nuclear translocation of ANXA1 was evaluated by subcellular extraction and immunofluorescence, and protein expression levels were detected by Western blot analysis. In addition, the activity of MMP-2/9 was measured by gelatin zymography. The results revealed that Tat-NTS significantly inhibited the nuclear translocation of ANXA1 in U87 cells and inhibited the proliferation, migration and invasion of GB cells. Tat-NTS also suppressed cell cycle regulatory proteins and MMP-2/-9 activity and expression. Moreover, Tat-NTS reduced the level of p-p65 NF-κB in U87 cells. These results suggest that the Tat-NTS-induced inhibition of GB cell proliferation, migration and invasion is closely associated with the induction of cell cycle arrest, downregulation of MMP-2/-9 expression and activity and suppression of the NF-κB signaling pathway. Thus, Tat-NTS may be a potential chemotherapeutic agent for the treatment of GB.

Association of maternal neutrophil count in early pregnancy with the development of gestational diabetes mellitus: a prospective cohort study in China.

OBJECTIVE: We evaluated the potential role of maternal serum levels of neutrophils in the first trimester of pregnancy in the prediction of gestational diabetes mellitus (GDM). METHODS: This prospective cohort study enrolled singleton pregnant women before gestational weeks 16 and evaluated them until delivery. Among the 1467 pregnant women who performed prenatal care before 14 weeks of gestation in the cohort, a total of 731 were eligible for the final analysis. The associations between neutrophil counts, white blood cell count, neutrophil to lymphocyte ratio, and GDM (assessed by a 75-g oral glucose tolerance test between 24 and 28 weeks) were evaluated by multivariate logistic regression. RESULTS: Neutrophil count outperformed the neutrophil to lymphocyte ratio and white blood cell count in predicting GDM occurrence. We applied a smoothing function and found that neutrophil count was associated with both fasting blood glucose (FBG) (p=.0149) and 1-h postprandial blood glucose (PBG) (p=.0187) after adjustment pre-pregnancy body mass index, family history of diabetes, and age. Logistic regression analysis found that the highest neutrophil count level (6.28-14.73 × 109/L) had a 1.85-fold (95% CI 1.10, 3.09) increased risk of GDM compared with that of the lowest tertile (1.47-4.82 × 109/L). CONCLUSIONS: The results indicated an association between higher neutrophil levels and GDM occurrence.

Long noncoding RNA PVT1 promotes breast cancer proliferation and metastasis by binding miR-128-3p and UPF1.

BACKGROUND: Mounting evidence supports that long noncoding RNAs (lncRNAs) have critical roles during cancer initiation and progression. In this study, we report that the plasmacytoma variant translocation 1 (PVT1) lncRNA is involved in breast cancer progression. METHODS: qRT-PCR and western blot were performed to detect the gene and protein expression. Colony formation would healing and transwell assays were used to detect cell function. Dual-luciferase reporter assay and RNA pull-down experiments were used to examine the mechanisms interaction between molecules. Orthotopic mouse models were established to evaluate the influence of PVT1 on tumor growth and metastasis in vivo. RESULTS: PVT1 is significant upregulated in breast cancer patients' plasma and cell lines. PVT1 promotes breast cancer cell proliferation and metastasis both in vitro and in vivo. Mechanistically, PVT1 upregulates FOXQ1 via miR-128-3p and promotes epithelial-mesenchymal transition. In addition, PVT1 binds to the UPF1 protein, thereby inducing epithelial-mesenchymal transition, proliferation and metastasis in breast cancer cells. CONCLUSION: PVT1 may act as an oncogene in breast cancer through binding miR-128-3p and UPF1 and represents a potential target for BC therapeutic development.

Carnitine palmitoyl transferase 1A is a novel diagnostic and predictive biomarker for breast cancer.

BACKGROUND: Carnitine palmitoyl transferase 1A (CPT1A), the key regulator of fatty acid oxidation, contributes to tumor metastasis and therapeutic resistance. We aimed to identify its clinical significance as a biomarker for the diagnosis and prediction of breast cancer. METHODS: Western blot, ELISA and in silico analysis were used to confirm CPT1A levels in breast cancer cell lines, cell culture medium and breast cancer tissues. Four hundred thirty breast cancer patients, 200 patients with benign breast disease, and 400 healthy controls were enrolled and randomly divided into a training set and a test set with a 7:3 ratio. Training set was used to build diagnostic models and 10-fold cross validation was used to demonstrate the performance of the models. Then test set was aimed to validate the effectiveness of the diagnostic models. ELISA was conducted to detect individual serum CPT1A levels. Receiver operating characteristic (ROC) curves were generated, and binary logistic regression analyses were performed to evaluate the effectiveness of CPT1A as a biomarker in breast cancer diagnosis. CPT1A levels between post-operative and pre-operative samples were also compared. RESULTS: CPT1A was overexpressed in breast cancer tissues, cell lines and cell culture medium. Serum CPT1A levels were higher in breast cancer patients than in controls and were significantly associated with metastasis, TNM stage, histological grading and molecular subtype. CPT1A levels were decreased in post-operative samples compared with paired pre-operative samples. Moreover, CPT1A exhibited a higher efficacy in differentiating breast cancer patients from healthy controls (training set: area under the curve, AUC, 0.892, 95% CI, 0.872-0.920; test set, AUC, 0.904, 95% CI, 0.869-0.939) than did CA15-3, CEA, or CA125. CONCLUSION: CPT1A is overexpressed in breast cancer and can be secreted out of breast cancer cell. Serum CPT1A is positively associated with breast cancer progression and could serve as an indicator for disease monitoring. Serum CPT1A displayed a remarkably high diagnostic efficiency for breast cancer and could be a novel biomarker for the diagnosis of breast cancer.

MicroRNA-301a promotes pancreatic cancer invasion and metastasis through the JAK/STAT3 signaling pathway by targeting SOCS5.

Pancreatic cancer is one of the most lethal digestive malignant tumors. We had previously found that microRNA-301a (miR-301a) is a oncogenic microRNA whose recognized conduce to nuclear factor-kappa B (NF-κB) activation in pancreatic cancer, yet the underlying mechanisms of miR-301a in promoting pancreatic cancer invasion and migration is obscure. In this work we found that high expression of miR-301a in human pancreatic cancer patients is related to poor survival. Overexpression of miR-301a enhances pancreatic cancer cell invasion, angiogenesis and migration, whereas inhibition of miR-301a suppresses pancreatic cancer cell invasion and reduces orthotopic pancreatic tumor growth and metastasis. Furthermore, suppressor of cytokine signaling 5 (SOCS5) is identified as a target gene of miR-301a. We found that miR-301a suppressed the expression of SOCS5 leads to janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) activation and is related to poor overall survival of pancreatic cancer patients. Taken together, our data show for the first time that the feedback loop between miR-301a and JAK/STAT3 pathway may play a significant role in pancreatic cancer invasion and metastasis. Targeting the loop may prove beneficial to prevent metastasis and provide a more effective therapeutic strategy for pancreatic cancer.

Annexin-1 Mimetic Peptide Ac2-26 Suppresses Inflammatory Mediators in LPS-Induced Astrocytes and Ameliorates Pain Hypersensitivity in a Rat Model of Inflammatory Pain.

Ac2-26, a mimetic peptide of Annexin-A1, plays a vital role in the anti-inflammatory response mediated by astrocytes. In this study, we aimed to explore the underlying mechanisms of Ac2-26-mediated anti-inflammatory effect. Specifically, we investigated the inhibitory effects of Ac2-26 on lipopolysaccharide (LPS)-induced astrocyte migration and on pro-inflammatory cytokines and chemokines expressions, as well as one glutathione (GSH) reductase mRNA and total intracellular GSH levels in LPS-induced astrocytes. Additionally, we investigated whether mitogen-activated protein kinases (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathway were involved in this process. Finally, we evaluated the analgesic effect of Ac2-26 in complete Freund's adjuvant (CFA)-induced inflammatory pain model. Our results demonstrated that Ac2-26 inhibited LPS-induced astrocytes migration, reduced the production of pro-inflammatory mediators [tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1 (MIP-1α)] and upregulated GSH reductase mRNA and GSH levels in LPS-induced astrocytes in vitro. This process was mediated through the p38, JNK-MAPK signaling pathway, but not dependent on the NF-κB pathway. Furthermore, the p38 and JNK inhibitors mimicked the effects of Ac2-26, whereas a p38 and JNK activator anisomycin partially reversed its function. Finally, Ac2-26 treatment reduced CFA-induced activation of astrocytes and production of inflammatory mediators in the spinal cord. These results suggest that Ac2-26 attenuates pain by inhibiting astrocyte activation and the production of inflammatory mediators; thus, this work presents Ac2-26 as a potential drug to treat neuropathic pain.

Higher level of neutrophil-to-lymphocyte is associated with severe COVID-19.

In December 2019, cases of severe coronavirus 2019 (COVID-19) infection rapidly progressed to acute respiratory failure. This study aims to assess the association between the neutrophil-to-lymphocyte ratio (NLR) and the incidence of severe COVID-19 infection. A retrospective cohort study was conducted on 210 patients with COVID-19 infection who were admitted to the Central Hospital of Wuhan from 27 January 2020 to 9 March 2020. Peripheral blood samples were collected and examined for lymphocyte subsets by flow cytometry. Associations between tertiles of NLR and the incidence of severe illness were analysed by logistic regression.Of the 210 patients with COVID-19, 87 were diagnosed as severe cases. The mean NLR of the severe group was higher than that of the mild group (6.6 vs. 3.3, P < 0.001). The highest tertile of NLR (5.1-19.7) exhibited a 5.9-fold (95% CI 1.3-28.5) increased incidence of severity relative to that of the lowest tertile (0.6-2.5) after adjustments for age, diabetes, hypertension and other confounders. The number of T cells significantly decreased in the severe group (0.5 vs. 0.9, P < 0.001). COVID-19 might mainly act on lymphocytes, particularly T lymphocytes. NLR was identified as an early risk factor for severe COVID-19 illness. Patients with increased NLR should be admitted to an isolation ward with respiratory monitoring and supportive care.

microRNA-21 promotes breast cancer proliferation and metastasis by targeting LZTFL1.

BACKGROUND: Breast cancer is the most common cancer type in female. As microRNAs play vital role in breast cancer, this study aimed to explore the molecular mechanism and clinical value of miR-21 in breast cancer. METHODS: qRT-PCR was performed to detect miR-21 levels in plasma of 127 healthy controls, 82 benign breast tumor, 252 breast cancer patients, as well as in breast cancer cell lines. Transwell and wound healing assay were used to analyze breast cancer metastasis in response to miR-21 inhibitor. Colony formation and eFluor™ 670 based flow cytometric analysis were used to test breast cancer proliferation following miR-21 inhibitor treatment. Leucine zipper transcription factor-like 1 (LZTFL1), the target gene of miR-21 was predicted by MIRDB, TargetScan 5.1, PicTar and miRanda. Survival analysis of LZTFL1 levels in breast cancer prognosis was estimated with the Kaplan-Meier method by log-rank test according to data from the Cancer Genome Atlas. Luciferase activity assay was performed to confirm the regulation of miR-21 on LZTFL1. LZTFL1 siRNA and miR-21 inhibitor were co-transfected to breast cancer cells, then cell proliferation, migration and epithelial-mesenchymal transition (EMT) makers were tested. BALB/c nude mice were injected in situ with Hs578T cells stably overexpressing miR-21. Breast tumor growth, metastasis and the expression of EMT markers or LZTFL1 were detected in vivo. RESULTS: Plasma miR-21 levels were elevated in breast cancer patients compared with healthy controls and benign breast tumor patients, and the miR-21 levels were significantly decreased after surgery comparing with pre operation in 44 patients. Inhibition of miR-21 suppressed cell proliferation and metastasis in breast cancer cells. LZTFL1 was identified as a novel target gene of miR-21. Knockdown of LZTFL1 overcame the suppression of miR-21 inhibitor on cell proliferation, metastasis and the expression of EMT markers in breast cancer cells. miR-21 overexpression promoted breast cancer cell proliferation and metastasis in vivo. CONCLUSIONS: These results indicate that plasma miR-21 level is a crucial biomarker for breast cancer diagnosis and targeting miR-21-LZTFL1-EMT axis might be a promising strategy in breast cancer therapy. TRIAL REGISTRATION: Retrospectively registered.

miR-331-3p functions as an oncogene by targeting ST7L in pancreatic cancer.

Pancreatic cancer (PC) is a highly invasive tumor with early metastasis and poor prognosis, yet the mechanisms for tumor progression have not been fully elucidated. Emerging evidence indicates that microRNA-331-3p (miR-331-3p) plays an important role in the progression of diverse human cancers. Here, we found that miR-331-3p was significantly upregulated in tumor specimens of PC patients and PC cell lines. Functional studies showed that downregulation of miR-331-3p inhibited PC cell proliferation and epithelial-mesenchymal transition (EMT)-mediated metastasis in vitro. Furthermore, suppression of tumorigenicity 7 like (ST7L) was identified as a novel target gene of miR-331-3p. Tumor promotion effects of miR-331-3p were partially reversed by ST7L re-expression. In addition, miR-331-3p antagomir suppressed PC tumor growth and metastasis via upregulation of ST7L in xenograft mice. In summary, these results demonstrate that miR-331-3p is a tumor-promoting microRNA (miRNA) in PC cells and a promising biomarker for PC.

The role of miR-200a in mammalian epithelial cell transformation.

Cancer is a multistep disease that begins with malignant cell transformation and frequently culminates in metastasis. MicroRNAs (miRNAs) are small regulatory 21-25 nt RNA molecules and are frequently deregulated in cancer. miR-200a is a member of the miR-200 family, which are known inhibitors of the epithelial-to-mesenchymal transition. As such, the tumor-suppressive role of miR-200a in oncogenesis has been well documented; however, recent studies have found a proliferative role for this miRNA as well as a prometastatic role in the later steps of cancer progression. Little is known about the role of this miRNA in the early stages of cancer, namely, malignant cell transformation. Here, we show that miR-200a alone transforms an immortalized rat epithelial cell line, and miR-200a cooperates with Ras to enhance malignant transformation of an immortalized human epithelial cell line. Furthermore, miR-200a induces cell transformation and tumorigenesis in immunocompromised mice by cooperating with a Ras mutant that activates only the RalGEF effector pathway, but not Ras mutants activating PI3K or Raf effector pathways. This transformative ability is in accordance with miR-200a targeting Fog2 and p53 to activate Akt and directly repress p53 protein levels, respectively. These results demonstrate an oncogenic role for miR-200a and provide a specific cellular context where miR-200a acts as an oncomiR rather than a tumor suppressor by cooperating with an oncogene in malignant cell transformation.

miR-25 targets the modulator of apoptosis 1 gene in lung cancer.

To determine the role of miR-25 in non-small cell lung cancer (NSCLC), we first detected miR-25 expression in clinical specimens and lung cancer cell lines by quantitative real-time polymerase chain reaction. The levels of miR-25 were elevated in the plasma of NSCLC patients and NSCLC cell lines. Transfection of A549 and 95-D cells with a miR-25 inhibitor resulted in reduced cell proliferation and enhanced apoptosis. Moreover, the modulator of apoptosis 1 (MOAP1) gene was identified as a novel target of miR-25. The ability of miR-25 to promote cell proliferation and block apoptosis is attributable to its effect on MOAP1 suppression. In addition, miR-25 antagomir significantly inhibited lung cancer growth via upregulation of MOAP1 in a mouse xenograft model. Collectively, these data demonstrate that miR-25 is an important biomarker for lung cancer, and miR-25 promotes cell proliferation and inhibits apoptosis in NSCLC cells by negatively regulating MOAP1 expression.

miR-301a as an NF-κB activator in pancreatic cancer cells.

NF-κB is constitutively activated in most human pancreatic adenocarcinoma, which is a deadly malignancy with a 5-year survival rate of about 5%. In this work, we investigate whether microRNAs (miRNAs) contribute to NF-κB activation in pancreatic cancer. We demonstrate that miR-301a down-regulates NF-κB-repressing factor (Nkrf) and elevates NF-κB activation. As NF-κB promotes the transcription of miR-301a, our results support a positive feedback loop as a mechanism for persistent NF-κB activation, in which miR-301a represses Nkrf to elevate NF-κB activity, which in turn promotes miR-301a transcription. Nkrf was found down-regulated and miR-301a up-regulated in human pancreatic adenocarcinoma tissues. Moreover, miR-301a inhibition or Nkrf up-regulation in pancreatic cancer cells led to reduced NF-κB target gene expression and attenuated xenograft tumour growth, indicating that miR-301a overexpression contributes to NF-κB activation. Revealing this novel mechanism of NF-κB activation by an miRNA offers new avenues for therapeutic interventions against pancreatic cancer.