Search

Purpose: To compare the effectiveness of transarterial embolization (TAE) using a liquid embolic (LE) to TAE using a particle embolic (PE) based on radiographic and histologic response in a translational rat model of hepatocellular carcinoma (HCC)., Materials and Methods: HCC was induced in Wistar rats using diethylnitrosamine. Tumor response was determined through RECIST applied to T2-weighted MRI scans. Tumor necrosis and hypoxia were assessed through hematoxylin and eosin and pimonidazole staining, respectively. Statistical analyses were performed using chi-square tests, Kaplan-Meier estimates, logistic regression and one-way analysis of variance (ANOVA), with significance set at p<0.05., Results: Twenty-nine rats were randomized to TAE with LE (n=13), PE (n=13), or sham (n=3). LE TAE demonstrated a significantly higher objective response rate (83%) compared to PE TAE (28%; χ2 = 11.25, P=0.0008). Complete responses were observed in 50% of the LE-treated tumors versus 10% in the PE-treated group. LE TAE prolonged local progression-free survival (hazard ratio = 0.31; P=0.032). Histological analysis of an additional 16 rats randomized to TAE with LE (n=7), PE (n=6), or sham (n=3), showed greater necrosis in LE-treated tumors compared to PE. LE induced a significant reduction in viable tumor tissue (p=0.009) and increased necrotic and necrotic + hypoxic tissue areas as compared to PE (p=0.003)., Conclusion: LE significantly enhanced the therapeutic efficacy of TAE in a rat model of HCC compared to PE. These results highlight the potential of LE's to improve ischemia and necrosis, thereby offering a promising option for improving the efficacy of embolization for HCC treatment., (Copyright © 2024. Published by Elsevier Inc.)

Background & Aims: Transarterial chemoembolization (TACE) is the most common treatment for hepatocellular carcinoma (HCC) worldwide; however, response rates and durability vary widely. With the growing armamentarium of therapies for HCC patients, identifying predictors of response to TACE has become increasingly important for a patient population with limited hepatic reserve. We hypothesized that a distinct metabolic phenotype associated with β-catenin pathway mutations render HCC tumors more susceptible to TACE-induced ischemia., Material and Methods: HCC patients referred for TACE were enrolled in a prospective cohort study at two academic medical centers from April 2016 to October 2021. Liver biopsies were acquired at the time of TACE, and mutational profiles were determined using next generation sequencing. Tumor response was determined by MRI using modified Response Evaluation Criteria in Solid Tumors. HCC cell lines with and without B-catenin mutations were grown in standard and ischemic cell culture conditions (1% O 2 , low nutrient media). Cell viability was measured by WST-1 reagent and Annexin-V PI assay. ATP concentration and metabolites were measured using CellTiter Glo and a YSI biochemical analyzer, respectively. Mitochondrial function was assessed through Seahorse XF Mito Stress Test., Results: 53 HCC tumors from 50 HCC patients were biopsied prior to TACE, including 22/53 (41.5%) tumors with β-catenin pathway mutations. Despite larger tumor size (4.9 cm vs 3.0 cm p=0.01), tumors with these mutations demonstrated increased rates of complete response after TACE at first imaging (9/22, 40.9% vs 6/31, 19.4%, p=0.06) and best response (12/22, 54.5% vs 7/31, 22.6%, p=0.02), as well as a longer time to tumor progression (median not yet reached vs 8.3 months, p=0.02). In vitro modeling confirmed that β-catenin mutant HCC cells have reduced viability (21.4% vs 59.9%, p<0.01) and ATP levels (8.47 vs 4.26 pM/cell, p<0.001) under ischemic conditions compared to β-catenin wild type HCC cells. β-catenin mutant HCC cells had a dramatic increase in their susceptibility to glycolysis inhibition that was not seen in wild type HCC cells (0.09 vs 0.79 IC50 ration for ischemic vs standard conditions, p=0.004), suggesting a change from predominantly aerobic to anaerobic metabolism under ischemia specific to β-catenin mutant. This was further supported by increased sensitivity of β-catenin mutant cells to inhibition of the electron transport chain (43.9% vs 59.5%, p=0.02,) as well as significantly higher basal oxygen consumption rates (0.74 vs 0.39 pmoles/min, p=0.04), maximal respiratory capacity (1.46 vs 0.51 pmoles/min, p=0.01) and ATP-linked respiration (0.58 vs 0.29 pmoles/min, p=0.04)., Conclusions: HCC tumors with activating B-catenin pathway mutations demonstrate a superior response to TACE, driven by enhanced susceptibility to ischemia due to a greater dependence on oxidative phosphorylation for bioenergetic homeostasis. These findings hold the potential to provide a molecular basis for treatment selection in patients with HCC., Impact and Implications: With the growing armamentarium of locoregional and systemic therapies for patients with HCC, identifying predictors of response to individual therapies has become increasingly important for a patient population with limited hepatic reserve. Current treatment guidelines fail to incorporate molecular biomarkers to inform therapy. In a prospective clinical study of HCC patients undergoing transarterial chemoembolization (TACE), we demonstrated that tumors with activating mutations in the Wnt/B-catenin pathway have increased rates of complete response and longer time to local progression. We further characterized this finding in vitro by modeling the post-TACE ischemic environment and demonstrated that B-catenin mutant HCC cells have a distinct metabolic phenotype that renders this subtype more susceptible to ischemia. These findings provide the rationale for genotype-based strategies to enable precision medicine for patients with HCC patients.

Background & Aims: Responses to immunotherapies in hepatocellular carcinoma (HCC) are suboptimal with no biomarkers to guide patient selection. "Humanized" mice represent promising models to address this deficiency but are limited by variable chimerism and underdeveloped myeloid compartments. We hypothesized that expression of human GM-CSF and IL-3 increases tumor immune cell infiltration, especially myeloid-derived cells, in humanized HCC patient-derived xenografts (PDXs)., Material and Methods: NOG (NOD/Shi- scid /IL-2R null ) and NOG-EXL (huGM-CSF/huIL-3 NOG) mice conditioned with Busulfan underwent i.v. injection of human CD34+ cells. HCC PDX tumors were then implanted subcutaneously (SQ) or orthotopically (OT). Following serial blood sampling, mice were euthanized at defined tumor sizes. Tumor, blood, liver, and spleen were analyzed by flow cytometry and immunohistochemistry., Results: Humanized NOG-EXL mice demonstrated earlier and increased human chimerism compared to humanized NOG mice (82.1% vs 43.8%, p<0.0001) with increased proportion of human monocytes (3.2% vs 1.1%, p=0.001) and neutrophils (0.8% vs 0.3%, p=0.02) in circulation. HCC tumors in humanized NOG-EXL mice had increased human immune cell infiltration (57.6% vs 30.2%, p=0.04), noting increased regulatory T cells (14.6% vs 6.8%, p=0.04), CD4+ PD-1 expression (84.7% vs 32.0%, p<0.01), macrophages (1.2% vs 0.6%, p=0.02), and neutrophils (0.5% vs 0.1%, p<0.0001). No differences were observed in tumor engraftment or growth latency in SQ tumors, but OT tumors required implantation at two rather than four weeks post-humanization for successful engraftment. Finally, utilizing adult bone marrow instead of fetal livers enabled partial HLA-matching to HCC tumors but required more CD34+ cells., Conclusions: Human GM-CSF and IL-3 expression in humanized mice resulted in features more closely approximating the immune microenvironment of human disease, providing a promising model for investigating critical questions in immunotherapy for HCC., Impact and Implications: This study introduces a unique mouse model at a critical point in the evolution of treatment paradigms for patients with hepatocellular carcinoma (HCC). Immunotherapies have become first line treatment for advanced HCC; however, response rates remain low with no clear predictors of response to guide patient selection. In this context, animal models that recapitulate human disease are greatly needed. Leveraging xenograft tumors derived from patients with advanced HCCs and a commercially available immunodeficient mouse strain that expresses human GM-CSF and IL-3, we demonstrate a novel but accessible approach for modeling the HCC tumor microenvironment.

Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: To evaluate the role of computed tomography (CT) and CT angiography in guiding endovascular arteriography (EA) and embolization in hemodynamically (HD) stable and unstable patients with abdominal and/or pelvic (AP) trauma., Materials and Methods: A retrospective review was performed of patients with AP trauma who underwent EA with or without embolization (from January 2012 to August 2020) at an urban, level I trauma center. Patients aged <18 years or those undergoing EA outside of the abdomen and/or pelvis were excluded. Demographics, imaging findings, procedure length, contrast agent administration, laboratory values, and outcomes were compared on the basis of preprocedural imaging technique and hemodynamic status., Results: A total of 190 patients with AP trauma underwent EA with or without embolization; among them, 123 were HD stable and underwent CT/CT angiography, whereas 67 were initially HD unstable and underwent operative management prior to EA. Of these patients, 38 underwent CT/CT angiography after hemodynamic stability was achieved prior to postoperative EA. The incidence of therapeutic embolization for arterial injury on EA was significantly higher in patients with preprocedural CT/CT angiography (65.8% vs 44.8%, P = .04). The positive and negative predictive values of CT angiography for arterial injury at the time of EA were 92.3% and 100%, respectively. Prior imaging was associated with a reduced contrast agent requirement at the time of EA and reduced transfusion requirement (P = .05 and P = .02). No significant differences were observed in adverse outcomes for patients undergoing preprocedural imaging., Conclusions: CT or CT angiography prior to EA for HD stable and unstable patients with AP trauma may improve the likelihood of therapeutic embolization and enable improved procedure metrics without increasing adverse outcomes., (Copyright © 2022 SIR. Published by Elsevier Inc. All rights reserved.)

Gastrointestinal cancers (GICs) and neuroendocrine tumors (NETs) are often refractory to therapy after metastasis. Adoptive cell therapy using chimeric antigen receptor (CAR) T cells, though remarkably efficacious for treating leukemia, is yet to be developed for solid tumors such as GICs and NETs. Here we isolated a llama-derived nanobody, VHH1, and found that it bound cell surface adhesion protein CDH17 upregulated in GICs and NETs. VHH1-CAR T cells (CDH17CARTs) killed both human and mouse tumor cells in a CDH17-dependent manner. CDH17CARTs eradicated CDH17-expressing NETs and gastric, pancreatic and colorectal cancers in either tumor xenograft or autochthonous mouse models. Notably, CDH17CARTs do not attack normal intestinal epithelial cells, which also express CDH17, to cause toxicity, likely because CDH17 is localized only at the tight junction between normal intestinal epithelial cells. Thus, CDH17 represents a class of previously unappreciated tumor-associated antigens that is 'masked' in healthy tissues from attack by CAR T cells for developing safer cancer immunotherapy., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background Transarterial embolization (TAE) is the most common treatment for hepatocellular carcinoma (HCC); however, there remain limited data describing the influence of TAE on the tumor immune microenvironment. Purpose To characterize TAE-induced modulation of the tumor immune microenvironment in a rat model of HCC and identify factors that modulate this response. Materials and Methods TAE was performed on autochthonous HCCs induced in rats with use of diethylnitrosamine. CD3, CD4, CD8, and FOXP3 lymphocytes, as well as programmed cell death protein ligand-1 ( PD-L1 ) expression, were examined in three cohorts: tumors from rats that did not undergo embolization (control), embolized tumors (target), and nonembolized tumors from rats that had a different target tumor embolized (nontarget). Differences in immune cell recruitment associated with embolic agent type (tris-acryl gelatin microspheres [TAGM] vs hydrogel embolics) and vascular location were examined in rat and human tissues. A generalized estimating equation model and t , Mann-Whitney U , and χ 2 tests were used to compare groups. Results Cirrhosis-induced alterations in CD8, CD4, and CD25/CD4 lymphocytes were partially normalized following TAE (CD8: 38.4%, CD4: 57.6%, and CD25/CD4: 21.1% in embolized liver vs 47.7% [ P = .02], 47.0% [ P = .01], and 34.9% [ P = .03], respectively, in cirrhotic liver [36.1%, 59.6%, and 4.6% in normal liver]). Embolized tumors had a greater number of CD3, CD4, and CD8 tumor-infiltrating lymphocytes relative to controls (191.4 cells/mm 2 vs 106.7 cells/mm 2 [ P = .03]; 127.8 cells/mm 2 vs 53.8 cells/mm 2 [ P < .001]; and 131.4 cells/mm 2 vs 78.3 cells/mm 2 [ P = .01]) as well as a higher PD-L1 expression score (4.1 au vs 1.9 au [ P < .001]). A greater number of CD3, CD4, and CD8 lymphocytes were found near TAGM versus hydrogel embolics (4.1 vs 2.0 [ P = .003]; 3.7 vs 2.0 [ P = .01]; and 2.2 vs 1.1 [ P = .03], respectively). The number of lymphocytes adjacent to embolics differed based on vascular location (17.9 extravascular CD68 + peri-TAGM cells vs 7.0 intravascular [ P < .001]; 6.4 extravascular CD68 + peri-hydrogel embolic cells vs 3.4 intravascular [ P < .001]). Conclusion Transarterial embolization-induced dynamic alterations of the tumor immune microenvironment are influenced by underlying liver disease, embolic agent type, and vascular location. © RSNA, 2022 Online supplemental material is available for this article. See also the editorials by Kennedy et al and by White in this issue.

In the era of precision medicine, biopsies are playing an increasingly central role in cancer research and treatment paradigms; however, patient outcomes and analyses of biopsy quality, as well as impact on downstream clinical and research applications, remain underreported. Herein, we report biopsy safety and quality outcomes for percutaneous core biopsies of hepatocellular carcinoma (HCC) performed as part of a prospective clinical trial. Patients with a clinical diagnosis of HCC were enrolled in a prospective cohort study for the genetic, proteomic, and metabolomic profiling of HCC at two academic medical centers from April 2016 to July 2020. Under image guidance, 18G core biopsies were obtained using coaxial technique at the time of locoregional therapy. The primary outcome was biopsy quality, defined as tumor fraction in the core biopsy. 56 HCC lesions from 50 patients underwent 60 biopsy events with a median of 8 core biopsies per procedure (interquartile range, IQR, 7-10). Malignancy was identified in 45/56 (80.4%, 4 without pathology) biopsy events, including HCC (40/56, 71.4%) and cholangiocarcinoma (CCA) or combined HCC-CCA (5/56, 8.9%). Biopsy quality was highly variable with a median of 40% tumor in each biopsy core (IQR 10-75). Only 43/56 (76.8%) and 23/56 (41.1%) samples met quality thresholds for genomic or metabolomic/proteomic profiling, respectively, requiring expansion of the clinical trial. Overall and major complication rates were 5/60 (8.3%) and 3/60 (5.0%), respectively. Despite uniform biopsy protocol, biopsy quality varied widely with up to 59% of samples to be inadequate for intended purpose. This finding has important consequences for clinical trial design and highlights the need for quality control prior to applications in which the presence of benign cell types may substantially alter findings., (© 2021. The Author(s).)

In this study, we describe new methods for studying cancer cell metabolism with hyperpolarized 13 C magnetic resonance spectroscopy (HP 13 C MRS) that will enable quantitative studies at low oxygen concentrations. Cultured hepatocellular carcinoma cells were grown on the surfaces of non-porous microcarriers inside an NMR spectrometer. They were perfused radially from a central distributer in a modified NMR tube (bioreactor). The oxygen level of the perfusate was continuously monitored and controlled externally. Hyperpolarized substrates were injected continuously into the perfusate stream with a newly designed system that prevented oxygen and temperature perturbations in the bioreactor. Computational and experimental results demonstrated that cell mass oxygen profiles with radial flow were much more uniform than with conventional axial flow. Further, the metabolism of HP [1- 13 C]pyruvate was markedly different between the two flow configurations, demonstrating the importance of avoiding large oxygen gradients in cell perfusion experiments.

This study investigates the in vivo pharmacokinetics and pharmacodynamics of hyperpolarized [1- 13 C]-pyruvate in a translational cancer model in order to inform the application of dynamic nuclear polarization (DNP)-enhanced magnetic resonance spectroscopic imaging (MRSI) as a tool for imaging liver cancer. Intratumoral metabolism within autochthonous hepatocellular carcinomas in male Wistar rats was analyzed by MRSI following hyperpolarized [1- 13 C]-pyruvate injections with 80 mM (low dose [LD]) or 160 mM (high dose [HD]) pyruvate. Rats received (i) LD followed by HD injection, (ii) sequential LD injections with or without an interposed lactate dehydrogenase inhibitor (LDHi) injection, or (iii) a single LD injection. A subset of rats in (ii) were sacrificed immediately after imaging, permitting measurement of active LDH concentrations in tumor extracts. Urine and serum were collected before and after injections for rats in (iii). Comparison of LD and HD injections confirmed concentration-dependent variation of intratumoral metabolite fractions and intermetabolite ratios. In addition, quantification of the lactate-to-pyruvate ratio was sensitive to pharmacologic inhibition with intermetabolite ratios correlating with active LDH concentrations in tumor extracts. Finally, comparison of pre- and post-DNP urine collections revealed that pyruvate and the radical source are renally excreted after injection. These data demonstrate that DNP-MRSI facilitates real-time quantification of intratumoral metabolism that is repeatable and reflective of intracellular processes. A translational model system confirmed that interpretation requires consideration of probe dose, administration frequency and excretion., (© 2021 John Wiley & Sons, Ltd.)

Purpose: Targeted therapies for cancer have accelerated the need for functional imaging strategies that inform therapeutic efficacy. This study assesses the potential of functional genetic screening to integrate therapeutic target identification with imaging probe selection through a proof-of-principle characterization of a therapy-probe pair using dynamic nuclear polarization (DNP)-enhanced magnetic resonance spectroscopic imaging (MRSI)., Experimental Design: CRISPR-negative selection screens from a public dataset were used to identify the relative dependence of 625 cancer cell lines on 18,333 genes. Follow-up screening was performed in hepatocellular carcinoma with a focused CRISPR library targeting imaging-related genes. Hyperpolarized [1- 13 C]-pyruvate was injected before and after lactate dehydrogenase inhibitor (LDHi) administration in male Wistar rats with autochthonous hepatocellular carcinoma. MRSI evaluated intratumoral pyruvate metabolism, while T 2 -weighted segmentations quantified tumor growth., Results: Genetic screening data identified differential metabolic vulnerabilities in 17 unique cancer types that could be imaged with existing probes. Among these, hepatocellular carcinoma required lactate dehydrogenase (LDH) for growth more than the 29 other cancer types in this database. LDH inhibition led to a decrease in lactate generation ( P < 0.001) and precipitated dose-dependent growth inhibition ( P < 0.01 overall, P < 0.05 for dose dependence). Intratumoral alanine production after inhibition predicted the degree of growth reduction ( P < 0.001)., Conclusions: These findings demonstrate that DNP-MRSI of LDH activity using hyperpolarized [1- 13 C]-pyruvate is a theranostic strategy for hepatocellular carcinoma, enabling quantification of intratumoral LDHi pharmacodynamics and therapeutic efficacy prediction. This work lays the foundation for a novel theranostic platform wherein functional genetic screening informs imaging probe selection to quantify therapeutic efficacy on a cancer-by-cancer basis., (©2020 American Association for Cancer Research.)

Background and Aims: Advances in cancer treatment have improved survival; however, local recurrence and metastatic disease-the principal causes of cancer mortality-have limited the ability to achieve durable remissions. Local recurrences arise from latent tumor cells that survive therapy and are often not detectable by conventional clinical imaging techniques. Local recurrence after transarterial embolization (TAE) of hepatocellular carcinoma (HCC) provides a compelling clinical correlate of this phenomenon. In response to TAE-induced ischemia, HCC cells adapt their growth program to effect a latent phenotype that precedes local recurrence., Approach and Results: In this study, we characterized and leveraged the metabolic reprogramming demonstrated by latent HCC cells in response to TAE-induced ischemia to enable their detection in vivo using dynamic nuclear polarization (DNP) magnetic resonance spectroscopic imaging (MRSI) of 13 carbon-labeled substrates. Under TAE-induced ischemia, latent HCC cells demonstrated reduced metabolism and developed a dependence on glycolytic flux to lactate. Despite the hypometabolic state of these cells, DNP-MRSI of 1- 13 C-pyruvate and its downstream metabolites, 1- 13 C-lactate and 1- 13 C-alanine, predicted histological viability., Conclusions: These studies provide a paradigm for imaging latent, treatment-refractory cancer cells, suggesting that DNP-MRSI provides a technology for this application., (© 2019 by the American Association for the Study of Liver Diseases.)

Molecular imaging of biologic molecules and cellular processes is increasingly accessible through hyperpolarization of chemically-equivalent stable isotopes, most commonly 13 C. However, many molecules are poor candidates for imaging due to their biophysical properties, particularly short spin-lattice relaxation times (T 1 ). The inability to consistently predict the T 1 from molecular structure, lack of experimental data for many biologically-relevant molecules and the high cost of developing probes can limit the development of hyperpolarized probes. We describe an in silico pipeline for modeling the estimated T 1 of molecules of interest in order to address this deficiency. Applying a hybrid approach that incorporates molecular dynamics as well as quantum mechanics, this pipeline estimated T 1 values that closely matched empirically determined values providing proof-of-principle that this approach may be used to facilitate MR probe development., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Inc.)

Tumour cells frequently utilize glutamine to meet bioenergetic and biosynthetic demands of rapid cell growth. However, glutamine dependence can be highly variable between in vitro and in vivo settings, based on surrounding microenvironments and complex adaptive responses to glutamine deprivation. Soft tissue sarcomas (STSs) are mesenchymal tumours where cytotoxic chemotherapy remains the primary approach for metastatic or unresectable disease. Therefore, it is critical to identify alternate therapies to improve patient outcomes. Using autochthonous STS murine models and unbiased metabolomics, we demonstrate that glutamine metabolism supports sarcomagenesis. STS subtypes expressing elevated glutaminase (GLS) levels are highly sensitive to glutamine starvation. In contrast to previous studies, treatment of autochthonous tumour-bearing animals with Telaglenastat (CB-839), an orally bioavailable GLS inhibitor, successfully inhibits undifferentiated pleomorphic sarcoma (UPS) tumour growth. We reveal glutamine metabolism as critical for sarcomagenesis, with CB-839 exhibiting potent therapeutic potential.

Purpose: To characterize angiographic and cross-sectional imaging anatomy of the rat visceral vasculature in 2 translational models., Materials and Methods: Animal studies were conducted in accordance with institutional guidelines and approval of the Institutional Animal Care and Use Committees. Retrospective review of digital subtraction arteriography was performed in 65 Wistar and 50 Sprague-Dawley male rats through a left common carotid artery or right common femoral artery approach. MR imaging of the abdomen was performed on the rats to correlate imaging modalities., Results: Aortography was performed in 3 locations, including cranial to the celiac artery, cranial to the renal arteries, and cranial to the caudal (inferior) mesenteric artery, enabling characterization of the visceral branch arteries in all 65 Wistar rats. Selective arteriography of first-, second-, and third-order branch vessels of the aorta was performed allowing characterization of normal and variant anatomy. Dedicated selective arteriography was performed of the celiac artery in 65 Wistar and 10 Sprague-Dawley rats, of the common hepatic artery in 65 Wistar and 50 Sprague-Dawley rats, and of the cranial mesenteric artery in 43 Wistar rats. MR imaging enabled correlation with the lobar and portal venous anatomy., Conclusions: Analysis of arteriography and MR imaging in these rat models will provide translational researchers with anatomic details needed to develop new endovascular protocols for small animal research in interventional radiology., (Copyright © 2019 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To establish the capability of near-infrared fluorescence (NIRF) imaging for the detection of matrix metalloproteinase 2 (MMP-2) activity as a biomarker of vascular remodeling (VR) in arteriovenous fistulae (AVFs) in vivo., Materials and Methods: AVFs were created in the right groins of Wistar rats (n = 10), and sham procedures were performed in the contralateral groins. Fistulography via a left common carotid artery approach confirmed stenosis (> 50%) in a subset of animals (n = 5) 4 weeks after AVF creation. After administration of MMP-2-activated NIRF probe, near-infrared imaging was performed in vivo and ex vivo of both the AVF and the sham-treated vessels to measure radiant efficiency of MMP-2-activated NIRF signal over background. Histologic analyses of AVF and sham-treated vessels were performed to measure VR defined as inward growth of the vessel caused by intimal thickening., Results: AVFs demonstrated a significantly higher percentage increase in radiant efficiency over background compared with sham vessels (45.5 ± 56% vs 16.1 ± 17.8%; P = .008). VR in AVFs was associated with increased thickness of neointima staining positively for MMP-2 (161.8 ± 45.5 μm vs 73.2 ± 36.7 μm; P = .01). A significant correlation was observed between MMP-2 activity as measured by relative increase in radiant efficiency for AVFs and thickness of neointima staining positively for MMP-2 (P = .039)., Conclusions: NIRF imaging can detect increased MMP activity in remodeled AVFs compared with contralateral sham vessels. MMP-2-activated NIRF signal correlates with the severity of intimal thickening. These findings suggest NIRF imaging of MMP-2 may be used as a biomarker of the vascular remodeling underlying stenosis., (Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose To characterize hepatocellular carcinoma (HCC) cells surviving ischemia with respect to cell cycle kinetics, chemosensitivity, and molecular dependencies that may be exploited to potentiate treatment with transarterial embolization (TAE). Materials and Methods Animal studies were performed according to institutionally approved protocols. The growth kinetics of HCC cells were studied in standard and ischemic conditions. Viability and cell cycle kinetics were measured by using flow cytometry. Cytotoxicity profiling was performed by using a colorimetric cell proliferation assay. Analyses of the Cancer Genome Atlas HCC RNA-sequencing data were performed by using Ingenuity Pathway Analysis software. Activation of molecular mediators of autophagy was measured with Western blot analysis and fluorescence microscopy. In vivo TAE was performed in a rat model of HCC with (n = 5) and without (n = 5) the autophagy inhibitor Lys05. Statistical analyses were performed by using GraphPad software. Results HCC cells survived ischemia with an up to 43% increase in the fraction of quiescent cells as compared with cells grown in standard conditions (P < .004). Neither doxorubicin nor mitomycin C potentiated the cytotoxic effects of ischemia. Gene-set analysis revealed an increase in mRNA expression of the mediators of autophagy (eg, CDKN2A, PPP2R2C, and TRAF2) in HCC as compared with normal liver. Cells surviving ischemia were autophagy dependent. Combination therapy coupling autophagy inhibition and TAE in a rat model of HCC resulted in a 21% increase in tumor necrosis compared with TAE alone (P = .044). Conclusion Ischemia induces quiescence in surviving HCC cells, resulting in a dependence on autophagy, providing a potential therapeutic target for combination therapy with TAE. © RSNA, 2017 Online supplemental material is available for this article.