Expression and Significance of PKM1 in Acute Myeloid Leukaemia.

OBJECTIVE: To investigate the expression level of pyruvate kinase M1 (PKM1) in patients with acute myeloid leukaemia (AML) as well as its clinical significance. STUDY DESIGN: A case-control study. Place and Duration of the Study: Department of Haematology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China, from January 2013 to 2023. METHODOLOGY: The expression levels of PKM1 and pyruvate kinase m2 (PKM2) in the bone marrow of 65 AML patients (excluding M3) and 31 healthy volunteers were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), a method that measures fluorescence in real-time. The associations between PKM1, PKM2 expressions, clinical parameters, and the survival and prognosis of AML patients were analysed. RESULTS: AML patients showed higher PKM1 expression compared to controls. The area under the curve (AUC) of the receiver operating characteristics (ROC) was 0.65 (p = 0.017). PKM1 expression was correlated with peripheral blood leukocyte count (r = -0.276, p = 0.026), CCAAT enhancer-binding protein alpha CEBPA mutation (r = -0.306, p = 0.014), and chemotherapy-induced response (r = -0.292, p = 0.018). Patients with high PKM1 expression had a lower remission rate (p = 0.019) and long-term survival rate (p = 0.034) than those with low PKM1 expression. Patients with AML showed a rise in PKM2 levels; however, the variation was not statistically significant (p >0.05). CONCLUSION: PKM1 expression is upregulated in AML and patients with high PKM1 expression have a lower survival rate. KEY WORDS: PKM1, Acute myeloid leukaemia, Clinical prognosis.

Differentiating ChatGPT-Generated and Human-Written Medical Texts: Quantitative Study.

BACKGROUND: Large language models, such as ChatGPT, are capable of generating grammatically perfect and human-like text content, and a large number of ChatGPT-generated texts have appeared on the internet. However, medical texts, such as clinical notes and diagnoses, require rigorous validation, and erroneous medical content generated by ChatGPT could potentially lead to disinformation that poses significant harm to health care and the general public. OBJECTIVE: This study is among the first on responsible artificial intelligence-generated content in medicine. We focus on analyzing the differences between medical texts written by human experts and those generated by ChatGPT and designing machine learning workflows to effectively detect and differentiate medical texts generated by ChatGPT. METHODS: We first constructed a suite of data sets containing medical texts written by human experts and generated by ChatGPT. We analyzed the linguistic features of these 2 types of content and uncovered differences in vocabulary, parts-of-speech, dependency, sentiment, perplexity, and other aspects. Finally, we designed and implemented machine learning methods to detect medical text generated by ChatGPT. The data and code used in this paper are published on GitHub. RESULTS: Medical texts written by humans were more concrete, more diverse, and typically contained more useful information, while medical texts generated by ChatGPT paid more attention to fluency and logic and usually expressed general terminologies rather than effective information specific to the context of the problem. A bidirectional encoder representations from transformers-based model effectively detected medical texts generated by ChatGPT, and the F1 score exceeded 95%. CONCLUSIONS: Although text generated by ChatGPT is grammatically perfect and human-like, the linguistic characteristics of generated medical texts were different from those written by human experts. Medical text generated by ChatGPT could be effectively detected by the proposed machine learning algorithms. This study provides a pathway toward trustworthy and accountable use of large language models in medicine.

Rapid phosphorylation of glucose-6-phosphate dehydrogenase by casein kinase 2 sustains redox homeostasis under ionizing radiation.

Exposure to ionizing radiation leads to oxidative damages in living cells. NADPH provides the indispensable reducing power to regenerate the reduced glutathione to maintain cellular redox equilibria. In mammalian cells, pentose phosphate pathway (PPP) is the major route to produce NADPH by using glycolytic intermediates, and the rate-limiting step of PPP is controlled by glucose-6-phosphate dehydrogenase (G6PD). Nevertheless, whether G6PD is timely co-opted under ionizing radiation to cope with oxidative stress remains elusive. Here we show that cellular G6PD activity is induced 30 min after ionizing radiation, while its protein expression is mostly unchanged. Mechanistically, casein kinase 2 (CK2) phosphorylates G6PD T145 under ionizing radiation, which consolidates the enzymatic activity of G6PD by facilitating G6PD binding with its substrate NADP+. Further, CK2-dependent G6PD T145 phosphorylation promotes NADPH production, decreases ROS level and supports cell proliferation under ionizing radiation. Our findings report a new anti-oxidative signaling route under ionizing radiation, by which CK2-mediated rapid activation of G6PD orchestrates NADPH synthesis to maintain redox homeostasis, thereby highlighting its potential value in the early treatment of ionizing radiation-induced injuries.

Cellular senescence implication in mustard keratopathy.

Mustard agents are vesicants that were used in warfare multiple times. They are potent alkylating agents that activate cellular pathways of apoptosis, increase oxidative stress, and induce inflammation. Eyes are particularly susceptible to mustard exposure with a wide range of ocular surface damage. Three main categories of mustard-related eye injuries are acute, chronic, and delayed-onset manifestations. Mustard keratopathy (MK) is a known complication characterized by corneal opacification, ulceration, thinning, and neovascularization that can lead to severe vision loss and discomfort. Recently, a few reports demonstrated the role of senescence induction as a new pathological mechanism in mustard-related injuries that could affect wound healing. We ran the first murine model of delayed-onset MK and nitrogen mustard-induced senescence, evaluating the pathological signs of senescence in the cornea using beta-galactosidase staining. Our results suggest that nitrogen mustard exposure causes senescence in the corneal cells, which could be the underlying mechanism for chronic and late-onset ocular surface damage. We also found a significant correlation between the percentage of positive beta-galactosidase staining and the degree of fibrosis in the cornea. This provides valuable insight into the possible role of anti-senescence drugs in the near future for accelerating corneal healing and restricting fibrosis in patients with mustard keratopathy.

Characterization of bone marrow heterogeneity in NK-AML (M4/M5) based on single-cell RNA sequencing.

Normal karyotype acute myeloid leukemia (NK-AML) is a heterogeneous hematological malignancy that contains a minor population of self-renewing leukemia stem cells (LSCs), which complicate efforts to achieve long-term survival. We performed single-cell RNA sequencing to profile 39,288 cells from 6 bone marrow (BM) aspirates including 5 NK-AML (M4/M5) patients and 1 healthy donor. The single-cell transcriptome atlas and gene expression characteristics of each cell population in NK-AML (M4/M5) and healthy BM were obtained. In addition, we identified a distinct LSC-like cluster with possible biomarkers in NK-AML (M4/M5) and verified 6 genes using qRT‒PCR and bioinformatic analyses. In conclusion, we utilized single-cell technologies to provide an atlas of NK-AML (M4/M5) cell heterogeneity, composition, and biomarkers with implications for precision medicine and targeted therapies.

MiR-181a-2-3p as a potential diagnostic and prognostic marker for myelodysplastic syndrome.

OBJECTIVE: Myelodysplastic syndrome (MDS) is a clonal bone marrow disorder with a high propensity to develop into acute myeloid leukemia (AML). Although abnormal microRNA expression has been implicated in MDS, the exact role of miR-181a-2-3p has not been entirely elucidated. Here, we investigated miR-181a-2-3p levels in bone marrow (BM), and described its utility as a potential indicator for MDS diagnosis and prognosis. METHODS: We evaluated miR-181a-2-3p expression in BM samples of 54 newly diagnosed MDS cases, 16 sAML patients and 32 healthy donors and then assessed its association with clinical characteristics and its potential value for MDS diagnosis and prognosis. RESULTS: Compared with healthy controls, miR-181a-2-3p levels were decreased in the total cohort of MDS patients. Additionally, in MDS patients with secondary AML (sAML), miR-181a-2-3p was over-expressed relative to levels in those without this form. The areas under the curve of receiver operating characteristic curves were 0.700 and 0.750 to distinguish MDS patients from controls and sAML from newly diagnosed MDS, respectively. Kaplan-Meier analysis showed a positive correlation between miR-181a-2-3p expression and overall survival (OS). Further, multivariate analysis indicated that miR-181a-2-3p was an independent prognostic index for MDS with respect to OS. CONCLUSION: Decreased miR-181a-2-3p expression in MDS patients may be considered as one of the underlying markers reflecting MDS progression and prognosis.

AMPK phosphorylates NAMPT to regulate NAD+ homeostasis under ionizing radiation.

Radiation-induced oral mucositis is the most common complication for patients who receive head/neck radiotherapy. Nicotinamide adenine dinucleotide (NAD+) is vital for DNA damage repair under ionizing radiation, through functioning as either the substrate for protein poly(ADP-ribosyl)ation at DNA break sites or the cofactor for multiple DNA repair-related enzymes, which therefore can result in a significant consumption of cellular NAD+ during DNA repair. Mammalian cells produce NAD+ mainly by recycling nicotinamide via the salvage pathway, in which the rate-limiting step is governed by nicotinamide phosphoribosyltransferase (NAMPT). However, whether NAMPT is co-opted under ionizing radiation to timely fine-tune NAD+ homeostasis remains elusive. Here we show that ionizing radiation evokes NAMPT activation within 30 min without apparent changes in its protein expression. AMPK rapidly phosphorylates NAMPT at S314 under ionizing radiation, which reinforces the enzymatic activity of NAMPT by increasing NAMPT binding with its substrate phosphoribosyl pyrophosphate (PRPP). AMPK-mediated NAMPT S314 phosphorylation substantially restores NAD+ level in the irradiated cells and facilitates DNA repair and cell viability. Our findings demonstrate a new post-translational modification-based signalling route, by which cells can rapidly orchestrate NAD+ metabolism to support DNA repair, thereby highlighting NAMPT as a potential target for the prevention of ionizing radiation-induced injuries.

An immune-related gene prognostic index for acute myeloid leukemia associated with regulatory T cells infiltration.

Acute myeloid leukemia (AML) is a malignant clonal disease characterized by abnormal proliferation of immature myeloid cells and bone marrow failure. Regulatory T cells (Treg) play a suppressive role in the anti-tumor immune response in the tumor microenvironment. Screening biomarkers based on Treg immune-related genes may help to predict the prognosis and the efficacy of immunotherapy of AML.Gene expression profiles of AML (non-M3) were obtained from the TCGA and GEO databases. Gene module related to Treg was extracted using CIBERSORT and WGCNA algorithms. Univariate Cox regression and LASSO analyses were performed to identify hub genes and constructed the immune prognostic model. Molecular and immunological features associated with risk signature were explored, and TIDE was used to predict the efficacy of immunotherapy.A risk signature was constructed based on the five IRGs (IFI27L1, YIPF6, PARVB, TRIM32 and RHOBTB3). The risk signature could be served as an independent prognostic factor of AML. Patients in the high-risk group had a poorer OS than those in the low-risk group. In addition, patients in the high-risk group had higher TP53 mutation rate, higher infiltration of Treg, higher immune escape potential and less benefit from ICI therapy compared to low-risk group.Our study constructed a prognostic index based on five Treg-related biomarkers, which help to facilitate the differentiation of immunological and molecular characteristics of AML, predict patient prognosis and provide a reference for predicting benefits from ICI therapy.

Expression and clinical significance of RAG1 in myelodysplastic syndromes.

OBJECTIVE: To determine the expression level of RAG1 and its clinical significance in myelodysplastic syndromes (MDS). METHODS: To explore the candidate genes, the microarray datasets GSE19429, GSE58831, and GSE2779 were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) in MDS were screened using RStudio, and overlapped DEGs were obtained with Venn Diagrams. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, and protein-protein interaction network were performed. Quantitative real-time PCR (qRT-PCR) was employed to confirm the microarray results. RESULTS: This study identified 26 DEGs. Functional enrichment analyses indicated that these DEGs were significantly enriched in the immune response, and hematopoietic cell lineage. Eight core genes, for example, RAG1 and PAX5, were identified with a high degree of connectivity. The result of qRT-PCR showed that RAG1 was significantly down-regulated in MDS patients, which helped in distinguishing MDS patients from normal controls. The area under the curve of the receiver operator characteristic was 0.913 (P < 0.0001). MDS patients with low RAG1 expression level had a poor long-term survival (P = 0.031). What's more, the expression of RAG1 was significantly increased in the patients who received treatment. CONCLUSION: The results showed that the expression of RAG1 was down-regulated in MDS patients. Lower RAG1 expression was associated with adverse clinical outcomes. RAG1 may be a potential prognostic biomarker for MDS.

IL-6/STAT3 Axis Activates Glut5 to Regulate Fructose Metabolism and Tumorigenesis.

Cancer cells frequently use fructose as an alternative energy and carbon source, to fuel glycolysis and support the synthesis of various biomacromolecules. Glut5 is the only fructose-specific transporter, which lacks the ability to transport other carbohydrates such as glucose and galactose. Interplay between inflammatory factors and cancer cells renders inflammatory tissue environment as a predisposing condition for cancer development. Nevertheless, how inflammatory factors coordinate with fructose metabolism to facilitate tumor growth remains largely elusive. Here we show that treatment with IL-6 activates fructose uptake and fructolysis in oral squamous cell carcinoma (OSCC) cells and prostate cancer cells. Mechanistic study shows that transcription factor STAT3 associates with Glut5 promoter region and enhances Glut5 transcription in response to IL-6 treatment. Knockdown of Glut5 abolished IL-6-induced fructose uptake and utilization of fructose, and compromises IL-6-elicited tumor cell proliferation. Further, positive correlation between Glut5 and IL-6 expression is observed in multiple cancers. Our findings demonstrate a regulatory cascade underlying the crosstalk between inflammation and fructose metabolism in cancer cells, and highlights Glut5 as a novel oncogenic factor.

Hippo pathway monomerizes STAT3 to regulate prostate cancer growth.

Prostate cancer ranks among the most commonly diagnosed malignancies for men and has become a non-negligible threat for public health. Interplay between inflammatory factors and cancer cells renders inflammatory tissue environment as a predisposing condition for cancer development. The Hippo pathway is a conserved signaling pathway across multiple species during evolution that regulates tissue homeostasis and organ development. Nevertheless, whether Hippo pathway regulates cancer-related inflammatory factors remains elusive. Here, we show that high cell density-mediated activation of the Hippo pathway blunts STAT3 activity in prostate cancer cells. Hippo pathway component MST2 kinase phosphorylates STAT3 at T622, which is located in the SH2 domain of STAT3. This phosphorylation blocks the SH2 domain in one STAT3 molecule to bind with the phosphorylated Y705 site in another STAT3 molecule, which further counteracts IL6-induced STAT3 dimerization and activation. Expression of a nonphosphorylatable STAT3 T622A mutant enhances STAT3 activity and IL6 expression at high cell density and promotes tumor growth in a mice xenograft model. Our findings demonstrate that STAT3 is a novel phosphorylation substrate for MST2 and thereby highlight a regulatory cascade underlying the crosstalk between inflammation and the Hippo pathway in prostate cancer cells.

Colorimetric and ratiometric fluorescent dual-mode sensitive detection of Hg2+ based on UiO-66-NH2@Au composite.

A colorimetric and ratiometric fluorescent dual-mode assay is constructed for sensitive and specific Hg2+ sensing based on UiO-66-NH2 and Au composite (UiO-66-NH2@Au). The addition of Hg2+ stimulates the peroxidase-like activity of UiO-66-NH2@Au by the formation of Au-Hg amalgam, promoting the oxidizing of chromogenic substrate OPD to DAP with the aid of H2O2, which lead to the change of colorimetric and fluorescent signals. The absorbance of the sensing system at 450 nm is linear positive correlation with Hg2+ concentration of 30-1400 nM and the color of the solution under visible light shaded from light yellow to dark yellow. With the increase of Hg2+ concentration, the fluorescence signal at 570 nm (DAP) increased whereas that at 455 nm (intrinsic fluorescence of UiO-66-NH2) decreased due to inner filter effect (IFE), the fluorescence intensity ratio (F455/F570) decreasing linearly with Log [Hg2+] over the range 60-1700 nM; the fluorescence emission of sensing system under UV excitation changed from blue to yellow, which can easily be discerned visually. This assay was successfully applied to the determination of Hg2+ in tap water and river water. The results indicate that the colorimetric and ratiometric fluorescent dual-mode assay based on UiO-66-NH2@Au realized visual determination of Hg2+ rapidly and reliably, revealed application prospect in Hg2+ monitoring.

Landscape of T Cells in NK-AML(M4/M5) Revealed by Single-Cell Sequencing.

Normal karyotype acute myeloid leukemia (NK-AML) is a highly heterogeneous malignancy that resides within a complex immune microenvironment, complicating efforts to reveal the interaction between leukemia cells and immune cells. Understanding tumor-infiltrating T cells is crucial to the advancement of immune therapies and the improvement of the prognosis for NK-AML patients. We performed single-cell RNA sequencing on bone marrow cells from 5 NK-AML (M4/M5) patients and 1 normal donor and paired single-cell T cell receptor (TCR) sequencing on single T cells. As a result, we identified 8 T cell clusters based on the gene expression characteristics of each subset in NK-AML and described their developmental trajectories. In NK-AML patients, specific clusters, such as mucosal-associated invariant T cells (MAITs), were preferentially enriched and potentially clonally expanded. These transcriptome and TCR data analyses provide valuable insights and rich resources for understanding the immune environment of NK-AML.

Gene body methylation safeguards ribosomal DNA transcription by preventing PHF6-mediated enrichment of repressive histone mark H4K20me3.

DNA methylation shows complex correlations with gene expression, and the role of promoter hypermethylation in repressing gene transcription has been well addressed. Emerging evidence indicates that gene body methylation promotes transcription; however, the underlying mechanisms remain to be further investigated. Here, using methylated DNA immunoprecipitation sequencing (MeDIP-seq), bisulfite genomic sequencing, and immunofluorescent labeling, we show that gene body methylation is indeed positively correlated with rRNA gene (rDNA) transcription. Mechanistically, gene body methylation is largely maintained by DNA methyltransferase 1 (DNMT1), deficiency or downregulation of which during myoblast differentiation or nutrient deprivation results in decreased gene body methylation levels, leading to increased gene body occupancy of plant homeodomain (PHD) finger protein 6 (PHF6). PHF6 binds to hypomethylated rDNA gene bodies where it recruits histone methyltransferase SUV4-20H2 to establish the repressive histone modification, H4K20me3, ultimately inhibiting rDNA transcription. These findings demonstrate that DNMT1-mediated gene body methylation safeguards rDNA transcription by preventing enrichment of repressive histone modifications, suggesting that gene body methylation serves to maintain gene expression in response to developmental and/or environmental stresses.

Duramycin radiosensitization of MCA-RH 7777 hepatoma cells through the elevation of reactive oxygen species.

OBJECTIVE: The objective of this study is to explore the radiosensitization effects of duramycin against the liver cancer hepatoma cells and relationship to reactive oxygen species (ROS) generation. MATERIALS AND METHODS: MCA-RH 7777 cells were treated with various combinations of duramycin concentrations and radiation doses. After the treatment, cell viabilities were determined by a cell proliferation assay; intracellular ROS levels were detected with the flow cytometric method. RESULTS: MCA-RH 7777 cell viability was found significantly reduced after combining duramycin and radiation exposure (comparing to that of either treatment alone). Increased intracellular ROS levels were observed in cells treated with combinations of duramycin and radiation. CONCLUSION: Duramycin increased the intracellular ROS generation and also increased the radiosensitivity of MCA-RH 7777 cells.

ATF3 drives senescence by reconstructing accessible chromatin profiles.

Chromatin organization and transcriptional profiles undergo tremendous reordering during senescence. However, uncovering the regulatory mechanisms between chromatin reconstruction and gene expression in senescence has been elusive. Here, we depicted the landscapes of both chromatin accessibility and gene expression to reveal gene regulatory networks in human umbilical vein endothelial cell (HUVEC) senescence and found that chromatin accessibilities are redistributed during senescence. Particularly, the intergenic chromatin was massively shifted with the increased accessibility regions (IARs) or decreased accessibility regions (DARs), which were mainly enhancer elements. We defined AP-1 transcription factor family as being responsible for driving chromatin accessibility reconstruction in IARs, where low DNA methylation improved binding affinity of AP-1 and further increased the chromatin accessibility. Among AP-1 transcription factors, we confirmed ATF3 was critical to reconstruct chromatin accessibility to promote cellular senescence. Our results described a dynamic landscape of chromatin accessibility whose remodeling contributes to the senescence program, we identified that AP-1 was capable of reorganizing the chromatin accessibility profile to regulate senescence.

Yttrium-90 Radioembolization and Tumor Hypoxia: Gas-challenge BOLD Imaging in the VX2 Rabbit Model of Hepatocellular Carcinoma.

RATIONALE AND OBJECTIVES: To use a rapid gas-challenge blood oxygen-level dependent magnetic resonance imaging exam to evaluate changes in tumor hypoxia after 90Y radioembolization (Y90) in the VX2 rabbit model. MATERIALS AND METHODS: White New Zealand rabbits (n = 11) provided a Y90 group (n = 6 rabbits) and untreated control group (n = 5 rabbits). R2* maps were generated with gas-challenges (O2/room air) at baseline, 1 week, and 2 weeks post-Y90. Laboratory toxicity was evaluated at baseline, 24 hours, 72 hours, 1 hours, and 2 weeks. Histology was used to evaluate tumor necrosis on hematoxylin and eosin and immunofluorescence imaging was used to assess microvessel density (CD31) and proliferative index (Ki67). RESULTS: At baseline, median tumor volumes and time to imaging were similar between groups (p = 1.000 and p = 0.4512, respectively). The median administered dose was 50.4 Gy (95% confidence interval:44.8-55.9). At week 2, mean tumor volumes were 5769.8 versus 643.7 mm3 for control versus Y90 rabbits, respectively (p = 0.0246). At two weeks, ΔR2* increased for control tumors to 12.37 ± 12.36sec-1 and decreased to 4.48 ± 9.00sec-1 after Y90. The Pearson correlation coefficient for ΔR2* at baseline and percent increase in tumor size by two weeks was 0.798 for the Y90 group (p = 0.002). There was no difference in mean microvessel density for control versus Y90 treated tumors (p = 0.6682). The mean proliferative index was reduced in Y90 treated tumors at 30.5% versus 47.5% for controls (p = 0.0071). CONCLUSION: The baseline ΔR2* of tumors prior to Y90 may be a predictive imaging biomarker of tumor response and treatment of these tumors with Y90 may influence tumor oxygenation over time.

Senescence-activated enhancer landscape orchestrates the senescence-associated secretory phenotype in murine fibroblasts.

The three-dimensional configuration of the chromatin architecture is known to be crucial for alterations in the transcriptional network; however, the underlying mechanisms of epigenetic control of senescence-related gene expression by modulating the chromatin architecture remain unknown. Here, we demonstrate frequent chromosomal compartment switching during mouse embryonic fibroblasts (MEFs) replicative senescence as characterized by senescence-inactivated (SIAEs) and -activated enhancers (SAEs) in topologically associated domains (TADs). Mechanistically, SAEs are closely correlated with senescence-associated secretory phenotype (SASP) genes, which are a key transcriptional feature of an aging microenvironment that contributes to tumor progression, aging acceleration, and immunoinflammatory responses. Moreover, SAEs can positively regulate robust changes in SASP expression. The transcription factor CCAAT/enhancer binding protein α (C/EBPα) is capable of enhancing SAE activity, which accelerates the emergence of SAEs flanking SASPs and the secretion of downstream factors, contributing to the progression of senescence. Our results provide novel insight into the TAD-related control of SASP gene expression by revealing hierarchical roles of the chromatin architecture, transcription factors, and enhancer activity in the regulation of cellular senescence.

Feasibility of Combination Intra-arterial Yttrium-90 and Irinotecan Microspheres in the VX2 Rabbit Model.

PURPOSE: To evaluate the combination of 90Y radioembolization (Y90) and drug-eluting bead irinotecan (DEBIRI) microspheres in the VX2 rabbit model. MATERIALS AND METHODS: An initial dose finding study was performed in 6 White New Zealand rabbits to identify a therapeutic but subcurative dose of Y90. In total, 29 rabbits were used in four groups: Y90 treatment (n = 8), DEBIRI treatment (n = 6), Y90 + DEBIRI treatment (n = 7), and an untreated control group (n = 8). Hepatic toxicity was evaluated at baseline, 24 h, 72 h, 1 week, and 2 weeks. MRI tumor volume (TV) and enhancing tumor volume were assessed baseline and 2 weeks. Tumor area and necrosis were evaluated on H&E for pathology. RESULTS: Infused activities of 84.0-94.4 MBq (corresponding to 55.1-72.7 Gy) were selected based on the initial dose finding study. Infusion of DEBIRI after Y90 was technically feasible in all cases (7/7). Overall, 21/29 animals survived to 2 weeks, and the remaining animals had extrahepatic disease on necropsy. Liver transaminases were elevated with Y90, DEBIRI, and Y90 + DEBIRI compared to control at 24 h, 72 h, and 1 week post-treatment and returned to baseline by 2 weeks. By TV, Y90 + DEBIRI was the only treatment to show statistically significant reduction at 2 weeks compared to the control group (p = 0.012). The change in tumor volume (week 2-baseline) for both Y90 + DEBIRI versus control (p = 0.002) and Y90 versus control (p = 0.014) was significantly decreased. There were no statistically significant differences among groups on pathology. CONCLUSION: Intra-arterial Y90 + DEBIRI was safe and demonstrated enhanced antitumor activity in rabbit VX2 tumors. This combined approach warrants further investigation.

Iron-Oxide Nanocluster Labeling of Clostridium novyi-NT Spores for MR Imaging-Monitored Locoregional Delivery to Liver Tumors in Rat and Rabbit Models.

PURPOSE: To label Clostridium novyi-NT spores (C. novyi-NT) with iron oxide nanoclusters and track distribution of bacteria during magnetic resonance (MR) imaging-monitored locoregional delivery to liver tumors using intratumoral injection or intra-arterial transcatheter infusion. MATERIALS AND METHODS: Vegetative state C. novyi-NT were labeled with iron oxide particles followed by induction of sporulation. Labeling was confirmed with fluorescence microscopy and transmission electron microscopy (TEM). T2 and T2* relaxation times for magnetic clusters and magnetic microspheres were determined using 7T and 1.5T MR imaging scanners. In vitro assays compared labeled bacteria viability and oncolytic potential to unlabeled controls. Labeled spores were either directly injected into N1-S1 rodent liver tumors (n = 24) or selectively infused via the hepatic artery in rabbits with VX2 liver tumors (n = 3). Hematoxylin-eosin, Prussian blue, and gram staining were performed. Statistical comparison methods included paired t-test and ANOVA. RESULTS: Both fluorescence microscopy and TEM studies confirmed presence of iron oxide labels within the bacterial spores. Phantom studies demonstrated that the synthesized nanoclusters produce R2 relaxivities comparable to clinical agents. Labeling had no significant impact on overall growth or oncolytic properties (P >.05). Tumor signal-to-noise ratio (SNR) decreased significantly following intratumoral injection and intra-arterial infusion of labeled spores (P <.05). Prussian blue and gram staining confirmed spore delivery. CONCLUSIONS: C. novyi-NT spores can be internally labeled with iron oxide nanoparticles to visualize distribution with MR imaging during locoregional bacteriolytic therapy involving direct injection or intra-arterial transcatheter infusion.