The Unfolded Protein Response Mediator PERK Governs Myeloid Cell-Driven Immunosuppression in Tumors through Inhibition of STING Signaling.

The primary mechanisms supporting immunoregulatory polarization of myeloid cells upon infiltration into tumors remain largely unexplored. Elucidation of these signals could enable better strategies to restore protective anti-tumor immunity. Here, we investigated the role of the intrinsic activation of the PKR-like endoplasmic reticulum (ER) kinase (PERK) in the immunoinhibitory actions of tumor-associated myeloid-derived suppressor cells (tumor-MDSCs). PERK signaling increased in tumor-MDSCs, and its deletion transformed MDSCs into myeloid cells that activated CD8+ T cell-mediated immunity against cancer. Tumor-MDSCs lacking PERK exhibited disrupted NRF2-driven antioxidant capacity and impaired mitochondrial respiratory homeostasis. Moreover, reduced NRF2 signaling in PERK-deficient MDSCs elicited cytosolic mitochondrial DNA elevation and, consequently, STING-dependent expression of anti-tumor type I interferon. Reactivation of NRF2 signaling, conditional deletion of STING, or blockade of type I interferon receptor I restored the immunoinhibitory potential of PERK-ablated MDSCs. Our findings demonstrate the pivotal role of PERK in tumor-MDSC functionality and unveil strategies to reprogram immunosuppressive myelopoiesis in tumors to boost cancer immunotherapy.

Using Voxel-based Dosimetry to evaluate sphere concentration and tumor dose in Hepatocellular Carcinoma treated with Y-90 Radiation Segmentectomy with glass microspheres.

PURPOSE: To utilize voxel-based dosimetry following radiation segmentectomy to understand microsphere distribution and validate current literature regarding radiologic and pathologic outcomes. METHODS: A retrospective, single-center analysis of solitary HCC patients (n=56) treated with Y90 radiation segmentectomy with glass microspheres (TheraSphere; Boston Scientific, Marlborough, MA, USA) from 2020 to 2022 was performed. Post-treatment voxel-based dosimetry was evaluated using Mirada DBx Build 1.2.0 Simplicit90Y software and utilized to calculate sphere concentration to tumor, as well as D70 (minimum dose to 70% total tumor volume), D90, and D99. Time to progression (TTP), treatment response, and adverse events were studied. RESULTS: Fifty-six solitary tumors were analyzed with a median tumor diameter of 3.4cm (range 1.2-6.8cm) and median tumor absorbed dose of 732Gy (range, 252-1776Gy). Median sphere activity (SA) at time of delivery was 1446Bq (range, 417-2621Bq). Median tumor sphere concentration was 12,868 spheres/mL (range, 2,655-37,183 spheres/mL). Sphere concentration into tumor and normal tissue inversely correlated with perfused treatment volume (R2=0.21 and 0.39, respectively). Of the 51 tumors with post-treatment imaging, objective response was noted in 49 patients (96%) and complete response in 42 patients (82%). The median TTP was not reached with a 2-year progression rate of 11%. 15 patients underwent liver transplant. Median tumor necrosis was 99% (range, 80-100%). Lower tumor volumes and higher D99 were associated with CPN (p<0.001 and p=0.022, respectively). CONCLUSION: Voxel-based dosimetry following Y90 radioembolization can be utilized to account for sphere deposition and distribution into tumor. Ablative RS with high SA yields durable radiologic and pathologic outcomes.

The stress-response sensor chop regulates the function and accumulation of myeloid-derived suppressor cells in tumors.

Adaptation of malignant cells to the hostile milieu present in tumors is an important determinant of their survival and growth. However, the interaction between tumor-linked stress and antitumor immunity remains poorly characterized. Here, we show the critical role of the cellular stress sensor C/EBP-homologous protein (Chop) in the accumulation and immune inhibitory activity of tumor-infiltrating myeloid-derived suppressor cells (MDSCs). MDSCs lacking Chop had decreased immune-regulatory functions and showed the ability to prime T cell function and induce antitumor responses. Chop expression in MDSCs was induced by tumor-linked reactive oxygen and nitrogen species and regulated by the activating-transcription factor-4. Chop-deficient MDSCs displayed reduced signaling through CCAAT/enhancer-binding protein-ß, leading to a decreased production of interleukin-6 (IL-6) and low expression of phospho-STAT3. IL-6 overexpression restored immune-suppressive activity of Chop-deficient MDSCs. These findings suggest the role of Chop in tumor-induced tolerance and the therapeutic potential of targeting Chop in MDSCs for cancer immunotherapy.

SLAMF1 is expressed and secreted by hepatocytes and the liver in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent forms of chronic liver disease in the United States and worldwide. Nonalcoholic steatohepatitis (NASH), the most advanced form of NAFLD, is characterized by hepatic steatosis associated with inflammation and hepatocyte death. No treatments are currently available for NASH other than lifestyle changes, and the disease lacks specific biomarkers. The signaling lymphocytic activation molecule family 1 (SLAMF1) protein is a self-ligand receptor that plays a role in orchestrating an immune response to some pathogens and cancers. We found that livers from humans and mice with NASH showed a more prominent immunohistochemistry staining for SLAMF1 than non-NASH controls. Furthermore, SLAMF1 levels are significantly increased in NASH plasma samples from mice and humans compared with their respective controls. In mice, the levels of SLAMF1 correlated significantly with the severity of the NASH phenotype. To test whether SLAMF 1 is expressed by hepatocytes, HepG2 cells and primary murine hepatocytes were treated with palmitic acid (PA) to induce a state of lipotoxicity mimicking NASH. We found that PA treatments of HepG2 cells and primary hepatocytes lead to significant increases in SLAMF1 levels. The downregulation of SLAMF1 in HepG2 cells improved the cell viability and reduced cytotoxicity. The in vivo data using mouse and human NASH samples suggests a potential role for this protein as a noninvasive biomarker for NASH. The in vitro data suggest a role for SLAMF1 as a potential therapeutic target to prevent hepatocyte death in response to lipotoxicity.NEW & NOTEWORTHY This study identified for the first time SLAMF1 as a mediator of hepatocyte death in nonalcoholic fatty liver disease (NASH) and as a marker of NASH in humans. There are no pharmacological treatments available for NASH, and diagnostic tools are limited to invasive liver biopsies. Therefore, since SLAMF1 levels correlate with disease progression and SLAMF1 mediates cytotoxic effects, this protein can be used as a therapeutic target and a clinical biomarker of NASH.

PD-1 expression in hepatocellular carcinoma predicts liver-directed therapy response and bridge-to-transplant survival.

BACKGROUND: Hepatocellular carcinoma (HCC) patients undergo liver-directed therapy (LDT) to control tumor burden while awaiting liver transplantation with response impacting waitlist survival. In this study, we investigate the link between absolute lymphocyte count (ALC) and PD-1 expression with response to LDT and bridge-to-transplant survival. METHODS: Treatment-naïve HCC patients (n = 86) undergoing LDT were enrolled at a single center from August 2016-March 2020. Response to LDT was determined using mRECIST. Blood samples were collected on the day of LDT and at follow-up. Cells were analyzed for phenotype by flow cytometry. Outcomes were liver transplantation or tumor progression. RESULTS: Incomplete response to initial LDT was associated with tumor progression precluding liver transplantation (OR: 7.6, 1.7 - 33.3, P < 0.001). Univariate analysis of baseline T cell phenotypes revealed ALC (OR: 0.44, 0.24-0.85, P = 0.009) as well as intermediate expression of PD-1 on CD4 (OR: 3.3, 1.03-10.3, P = 0.034) and CD8 T cells (OR: 3.0, 0.99-8.8 P = 0.043) associated with incomplete response to LDT. Elevations in PD-1 expression were associated with increased risk of bridge-to-transplant tumor progression (HR: 3.2, 1.2-9.4). In patients successfully bridged to liver transplantation, pre-treatment peripheral PD-1 profile was associated with advanced tumor staging (P < 0.005) with 2/4 of patients with elevations in PD-1 having T3-T4 TNM staging compared to 0 with low PD-1 expression. CONCLUSION: Low lymphocyte count or elevated expression of the PD-1 checkpoint inhibitor is associated with incomplete response to LDT and increased risk of bridge-to-transplant tumor progression. Patients with impaired T cell homeostasis may benefit from PD-1 immunotherapy to improve response to LDT and improve bridge-to-transplant outcomes.

Assessment of Response to Transcatheter Arterial Chemoembolization with Doxorubicin-eluting Microspheres: Tumor Biology and Hepatocellular Carcinoma Recurrence in a 5-year Transplant Cohort.

Purpose To assess response to transcatheter arterial chemoembolization (TACE) based on immune markers and tumor biology in patients with hepatocellular carcinoma (HCC) who were bridged to liver transplantation, and to produce an optimized pretransplantation model for posttransplantation recurrence risk. Materials and Methods In this institutional review board-approved HIPAA-compliant retrospective analysis, 93 consecutive patients (73 male, 20 female; mean age, 59.6 years; age range, 23-72 years) underwent TACE with doxorubicin-eluting microspheres (DEB) (hereafter, DEB-TACE) and subsequently underwent transplantation over a 5-year period from July 7, 2011, to May 16, 2016. DEB-TACE response was based on modified Response Evaluation Criteria in Solid Tumors. Imaging responses and posttransplantation recurrence were compared with demographics, liver function, basic immune markers, treatment dose, and tumor morphology. Treatment response and recurrence were analyzed with uni- and multivariate statistics, as well as internal validation and propensity score matching of factors known to affect recurrence to assess independent effects of DEB-TACE response on recurrence. Results Low-grade tumors (grade 0, 1, or 2) demonstrated a favorable long-term treatment response in 87% of patients (complete response, 49%; partial response, 38%; stable disease [SD] or local disease progression [DP], 13%) versus 33% of high-grade tumors (grade 3 or 4) (complete response, 0%; partial response, 33%; SD or DP, 67%) (P < .001). Of the 93 patients who underwent treatment, 82 were followed-up after transplantation (mean duration, 757 days). Recurrence occurred in seven (9%) patients (mean time after transplantation, 635 days). Poor response to DEB-TACE (SD or DP) was present in 86% of cases and accounted for 35% of all patients with SD or DP (P < .001). By using only variables routinely available prior to liver transplantation, a validated model of posttransplantation recurrence risk was produced with a concordance statistic of 0.83. The validated model shows sensitivity of 83.6%, specificity of 82.6%, and negative predictive value of 98.4%, which are pessimistic estimates. Conclusion Response to DEB-TACE is correlated with tumor biology and patients at risk for posttransplantation recurrence, and it may be associated with HCC recurrence after liver transplantation. © RSNA, 2017 Online supplemental material is available for this article.

Complement Activation in Liver Transplantation: Role of Donor Macrosteatosis and Implications in Delayed Graft Function.

The complement system anchors the innate inflammatory response by triggering both cell-mediated and antibody-mediated immune responses against pathogens. The complement system also plays a critical role in sterile tissue injury by responding to damage-associated molecular patterns. The degree and duration of complement activation may be a critical variable controlling the balance between regenerative and destructive inflammation following sterile injury. Recent studies in kidney transplantation suggest that aberrant complement activation may play a significant role in delayed graft function following transplantation, confirming results obtained from rodent models of renal ischemia/reperfusion (I/R) injury. Deactivating the complement cascade through targeting anaphylatoxins (C3a/C5a) might be an effective clinical strategy to dampen reperfusion injury and reduce delayed graft function in liver transplantation. Targeting the complement cascade may be critical in donor livers with mild to moderate steatosis, where elevated lipid burden amplifies stress responses and increases hepatocyte turnover. Steatosis-driven complement activation in the donor liver may also have implications in rejection and thrombolytic complications following transplantation. This review focuses on the roles of complement activation in liver I/R injury, strategies to target complement activation in liver I/R, and potential opportunities to translate these strategies to transplanting donor livers with mild to moderate steatosis.

Subpopulations of myeloid-derived suppressor cells impair T cell responses through independent nitric oxide-related pathways.

The accumulation of myeloid-derived suppressor cells (MDSC) in tumor-bearing hosts is a hallmark of malignancy-associated inflammation and a major mediator for the induction of T cell suppression in cancer. MDSC can be divided phenotypically into granulocytic (G-MDSC) and monocytic (Mo-MDSC) subgroups. Several mechanisms mediate the induction of T cell anergy by MDSC; however, the specific role of these pathways in the inhibitory activity of MDSC subpopulations remains unclear. Therefore, we aimed to determine the effector mechanisms by which subsets of tumor-infiltrating MDSC block T cell function. We found that G-MDSC had a higher ability to impair proliferation and expression of effector molecules in activated T cells, as compared to Mo-MDSC. Interestingly, both MDSC subgroups inhibited T cells through nitric oxide (NO)-related pathways, but expressed different effector inhibitory mechanisms. Specifically, G-MDSC impaired T cells through the production of peroxynitrites (PNT), while Mo-MDSC suppressed by the release of NO. The production of PNT in G-MDSC depended on the expression of gp91(phox) and endothelial NO synthase (eNOS), while inducible NO synthase (iNOS) mediated the generation of NO in Mo-MDSC. Deletion of eNOS and gp91(phox) or scavenging of PNT blocked the suppressive function of G-MDSC and induced anti-tumoral effects, without altering Mo-MDSC inhibitory activity. Furthermore, NO-scavenging or iNOS knockdown prevented Mo-MDSC function, but did not affect PNT production or suppression by G-MDSC. These results suggest that MDSC subpopulations utilize independent effector mechanisms to regulate T cell function. Inhibition of these pathways is expected to specifically block MDSC subsets and overcome immune suppression in cancer.

Lineage-specific regulation of PD-1 expression in early-stage hepatocellular carcinoma following 90yttrium transarterial radioembolization - Implications in treatment outcomes.

BACKGROUND: Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related deaths in the world. Liver-directed therapies, including 90Yttrium (90Y) radioembolization, play an integral role in the management of HCC with excellent response rates. This has led to clinical trials of immunotherapy in combination with 90Y. Elevated PD-1 expression and lymphopenia were recently shown as risk factors for disease progression in early-stage HCC treated with liver-directed therapies. The aim of this study was to investigate PD-1 expression dynamics in bridge/downstage to transplant in HCC patients receiving first-cycle 90Y and evaluate the impact of these changes on response rates and time-to-progression (TTP). METHODS: Patients with HCC receiving first-cycle 90Y as a bridge to liver transplantation (n = 99) were prospectively enrolled. Blood specimens were collected before 90Y and again during routine imagining follow-up to analyze PD-1 expression via flow cytometry. Complete and objective response rates (CR and ORR) were determined using mRECIST. RESULTS: In 84/88 patients with available follow-up imaging, 83% had a localized ORR with 63% having localized CR. For overall response, 71% and 54% experienced ORR and CR, respectively. Post-90Y PD-1 upregulation in CD8 + associated with HCC progression and decreased TTP. Treatment with 90Y was associated with an anticipated significant post-treatment drop in lymphocytes (P < 0.001) that was independent of PD-1 expression for either CD4+ or CD8+ T cells (P = 0.751 and P = 0.375) and not associated with TTP risk. The change in lymphocytes was not correlated with PD-1 expression following treatment nor TTP. CONCLUSIONS: Elevated PD-1 expression on peripheral T cells is associated with increased risk of HCC progression and shorter time to progression in bridging/downstaging to transplant HCC patients undergoing first-cycle 90Y. Treatment-induced lymphopenia was not associated with treatment response, or increased progression risk, suggesting this anticipated adverse event does not impact short-term HCC outcomes.

Imaging Delay Following Liver-Directed Therapy Increases Progression Risk in Early- to Intermediate-Stage Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related deaths in the world. Patients with early-stage HCC are treated with liver-directed therapies to bridge or downstage for liver transplantation (LT). In this study, the impact of HCC care delay on HCC progression among early-stage patients was investigated. Early-stage HCC patients undergoing their first cycle of liver-directed therapy (LDT) for bridge/downstaging to LT between 04/2016 and 04/2022 were retrospectively analyzed. Baseline variables were analyzed for risk of disease progression and time to progression (TTP). HCC care delay was determined by the number of rescheduled appointments related to HCC care. The study cohort consisted of 316 patients who received first-cycle LDT. The HCC care no-show rate was associated with TTP (p = 0.004), while the overall no-show rate was not (p = 0.242). The HCC care no-show rate and HCC care delay were further expanded as no-show rates and rescheduled appointments for imaging, laboratory, and office visits, respectively. More than 60% of patients experienced HCC care delay for imaging and laboratory appointments compared to just 8% for office visits. Multivariate analysis revealed that HCC-specific no-show rates and HCC care delay for imaging (p < 0.001) were both independently associated with TTP, highlighting the importance of minimizing delays in early-stage HCC imaging surveillance to reduce disease progression risk.

Radical-containing ultrafine particulate matter initiates epithelial-to-mesenchymal transitions in airway epithelial cells.

Environmentally persistent free radicals (EPFRs) in combustion-generated particulate matter (PM) are capable of inducing pulmonary pathologies and contributing to the development of environmental asthma. In vivo exposure of infant rats to EPFRs demonstrates their ability to induce airway hyperresponsiveness to methacholine, a hallmark of asthma. However, the mechanisms by which combustion-derived EPFRs elicit in vivo responses remain elusive. In this study, we used a chemically defined EPFR consisting of approximately 0.2 µm amorphrous silica containing 3% cupric oxide with the organic pollutant 1,2-dichlorobenzene (DCB-230). DCB-230 possesses similar radical content to urban-collected EPFRs but offers several advantages, including lack of contaminants and chemical uniformity. DCB-230 was readily taken up by BEAS-2B and at high doses (200 µg/cm(2)) caused substantial necrosis. At low doses (20 µg/cm(2)), DCB-230 particles caused lysosomal membrane permeabilization, oxidative stress, and lipid peroxidation within 24 hours of exposure. During this period, BEAS-2B underwent epithelial-to-mesenchymal transition (EMT), including loss of epithelial cell morphology, decreased E-cadherin expression, and increased α-smooth muscle actin (α-SMA) and collagen I production. Similar results were observed in neonatal air-liquid interface culture (i.e., disruption of epithelial integrity and EMT). Acute exposure of infant mice to DCB-230 resulted in EMT, as confirmed by lineage tracing studies and evidenced by coexpression of epithelial E-cadherin and mesenchymal α-SMA proteins in airway cells and increased SNAI1 expression in the lungs. EMT in neonatal mouse lungs after EPFR exposure may provide an explanation for epidemiological evidence supporting PM exposure and increased risk of asthma.

Model combustion-generated particulate matter containing persistent free radicals redox cycle to produce reactive oxygen species.

Particulate matter (PM) is emitted during thermal decomposition of waste. During this process, aromatic compounds chemisorb to the surface of metal-oxide-containing PM, forming a surface-stabilized environmentally persistent free radical (EPFR). We hypothesized that EPFR-containing PM redox cycle to produce ROS and that this redox cycle is maintained in biological environments. To test our hypothesis, we incubated model EPFRs with the fluorescent probe dihydrorhodamine (DHR). Marked increases in DHR fluorescence were observed. Using a more specific assay, hydroxyl radicals ((•)OH) were also detected, and their level was further increased by cotreatment with thiols or ascorbic acid (AA), known components of epithelial lining fluid. Next, we incubated our model EPFR in bronchoalveolar lavage fluid (BALF) or serum. Detection of EPFRs and (•)OH verified that PM generate ROS in biological fluids. Moreover, incubation of pulmonary epithelial cells with EPFR-containing PM increased (•)OH levels compared to those in PM lacking EPFRs. Finally, measurements of oxidant injury in neonatal rats exposed to EPFRs by inhalation suggested that EPFRs induce an oxidant injury within the lung lining fluid and that the lung responds by increasing antioxidant levels. In summary, our EPFR-containing PM redox cycle to produce ROS, and these ROS are maintained in biological fluids and environments. Moreover, these ROS may modulate toxic responses of PM in biological tissues such as the lung.

Chronic alcohol induces M2 polarization enhancing pulmonary disease caused by exposure to particulate air pollution.

BACKGROUND: Chronic alcohol consumption causes persistent oxidative stress in the lung, leading to impaired alveolar macrophage (AM) function and impaired immune responses. AMs play a critical role in protecting the lung from particulate matter (PM) inhalation by removing particulates from the airway and secreting factors which mediate airway repair. We hypothesized AM dysfunction caused by chronic alcohol consumption increases the severity of injury caused by PM inhalation. METHODS: Age- and sex-matched C57BL/6 mice were fed the Lieber-DeCarli liquid diet containing either alcohol or an isocaloric substitution (control diet) for 8 weeks. Mice from both diet groups were exposed to combustion-derived PM (CDPM) for the final 2 weeks. AM number, maturation, and polarization status were assessed by flow cytometry. Noninvasive and invasive strategies were used to assess pulmonary function and correlated with histomorphological assessments of airway structure and matrix deposition. RESULTS: Co-exposure to alcohol and CDPM decreased AM number and maturation status (CD11c expression), while increasing markers of M2 activation (interleukin [IL]-4Rα, Ym1, Fizz1 expression, and IL-10 and transforming growth factor [TGF]-ß production). Changes in AM function were accompanied by decreased airway compliance and increased elastance. Altered lung function was attributable to elevated collagen content localized to the small airways and loss of alveolar integrity. Intranasal administration of neutralizing antibody to TGF-ß during the CDPM exposure period improved changes in airway compliance and elastance, while reducing collagen content caused by co-exposure. CONCLUSIONS: Combustion-derived PM inhalation causes enhanced disease severity in the alcoholic lung by stimulating the release of latent TGF-ß stores in AMs. The combinatorial effect of elevated TGF-ß, M2 polarization of AMs, and increased oxidative stress impairs pulmonary function by increasing airway collagen content and compromising alveolar integrity.

A Single-Step Immunocapture Assay to Quantify HCC Exosomes Using the Highly Sensitive Fluorescence Nanoparticle-Tracking Analysis.

Introduction: Extracellular vesicles could serve as a non-invasive biomarker for early cancer detection. However, limited methods to quantitate cancer-derived vesicles in the native state remain a significant barrier to clinical translation. Aim: This research aims to develop a rapid, one-step immunoaffinity approach to quantify HCC exosomes directly from a small serum volume. Methods: HCC-derived exosomes in the serum were captured using fluorescent phycoerythrin (PE)-conjugated antibodies targeted to GPC3 and alpha-fetoprotein (AFP). Total and HCC-specific exosomes were then quantified in culture supernatant or patient-derived serums using fluorescence nanoparticle tracking analysis (F-NTA). The performance of HCC exosome quantification in the serum was compared with the tumor size determined by MRI. Results: Initially we tested the detection limits of the F-NTA using synthetic fluorescent and non-fluorescent beads. The assay showed an acceptable sensitivity with a detection range of 104-108 particles/mL. Additionally, the combination of immunocapture followed by size-exclusion column purification allows the isolation of smaller-size EVs and quantification by F-NTA. Our assay demonstrated that HCC cell culture releases a significantly higher quantity of GPC3 or GPC3+AFP positive EVs (100-200 particles/cell) compared to non-HCC culture (10-40 particles/cell) (p<0.01 and p<0.05 respectively). The F-NTA enables absolute counting of HCC-specific exosomes in the clinical samples with preserved biological immunoreactivity. The performance of F-NTA was clinically validated in serum from patients ± cirrhosis and with confirmed HCC. F-NTA quantification data show selective enrichment of AFP and GPC3 positive EVs in HCC serum compared to malignancy-free cirrhosis (AUC values for GPC3, AFP, and GPC3/AFP were found 0.79, 0.71, and 0.72 respectively). The MRI-confirmed patient cohort indicated that there was a positive correlation between total tumor size and GPC3-positive exosome concentration (r:0.78 and p<0.001). Conclusion: We developed an immunocapture assay that can be used for simultaneous isolation and quantification of HCC-derived exosomes from a small serum volume with high accuracy.

The number of hepatocellular carcinoma foci as predictor of poor response to tumor-directed therapies in patients awaiting liver transplantation: a prospective cohort study.

BACKGROUND AND AIMS: Tumor-directed therapies (TDTs) are a constitutive part of hepatocellular carcinoma (HCC) treatment in patients awaiting liver transplantation (LT). While most patients benefit from TDTs as a bridge to LT, some patients drop out from the waiting list due to tumor progression. The study aimed to determine the risk factors for poor treatment outcome following TDTs among patients with HCC awaiting LT. METHODS: A total of 123 patients with HCC were evaluated with 92 patients meeting Milan Criteria enrolled in the prospective cohort study. Tumor response was evaluated using the modified Response Evaluation Criteria for Solid Tumors for HCC 1 month after the procedure. The risk factors for progressive disease (PD) and dropout were evaluated. RESULTS: After TDT, 55 patients (59.8%) achieved complete or partial response (44.6% and 15.2% respectively), 17 patients (18.5%) had stable disease, and 20 patients (21.7%) were assessed as PD. Multivariate analysis revealed a significant and independent association between the number of HCC foci and PD ( P  = 0.03, OR = 2.68). There was no statistically significant association between treatment response and demographics, MELDNa score, pre-and post-treatment alpha-fetoprotein (AFP), cumulative tumor burden the largest tumor size, or TDT modality. PD was the major cause of dropout in our cohort. Pre-treatment AFP levels ≥200 ng/ml had a strong association with dropout after TDTs ( P  = 0.0005). CONCLUSION: This study demonstrated the presence of multifocal HCC is the sole prognostic factor for PD following TDTs in HCC patients awaiting LT. We recommend prioritizing patients with multifocal HCC within Milan criteria by exception points for LT to improve the dropout rate.

Distinct Gene Expression Profiles in Viable Hepatocellular Carcinoma Treated With Liver-Directed Therapy.

Background: Hepatocellular carcinoma is a heterogeneous tumor that accumulates a mutational burden and dysregulated signaling pathways that differ from early to advanced stages. Liver transplant candidates with early-stage hepatocellular carcinoma (HCC) undergo liver-directed therapy (LDT) to delay disease progression and serve as a bridge to liver transplantation (LT). Unfortunately, >80% of LDT-treated patients have viable HCC in the explant liver, dramatically increasing recurrence risk. Understanding the effect of LDT on early-stage HCC could help identify therapeutic targets to promote complete pathologic necrosis and improve recurrence-free survival. In this study, transcriptomic data from viable HCC in LDT-treated bridged to transplant patients were investigated to understand how treatment may affect tumor signaling pathways. Methods: Multiplex transcriptomic gene analysis was performed with mRNA extracted from viable tumors of HCC patients bridged to transplant using LDT. The NanoString nCounter® Tumor Signaling 360 panel was used that contained 780 genes from 48 pathways involved in tumor biology within the microenvironment as well as antitumoral immune responses. Results: Hierarchical clustering separated tumors into three subtypes (HCC-1, HCC-2, and HCC-3) each with distinct differences in anti-tumoral signaling and immune infiltration within the tumor microenvironment. Immune infiltration (neutrophils, T cells, and macrophages) were all lowest in subtype HCC-3. The tumor inflammatory signature consisting of 18 genes associated with PD-1/PD-L1 inhibition, antigen presentation, chemokine secretion, and adaptive immune responses was highest in subtype HCC-1 and lowest in HCC-3. History of decompensation and etiology were associated with HCC subtype favoring downregulations in inflammation and immune infiltration with upregulation of lipid metabolism. Gene expression among intrahepatic lesions was remarkably similar with >85% of genes expressed in both lesions. Genes differentially expressed (<8 genes per patient) in multifocal disease were all upregulated in LDT-treated tumors from pathways involving epithelial mesenchymal transition, extracellular matrix remodeling, and/or inflammation potentially implicating intrahepatic metastases. Conclusion: Incomplete response to LDT may drive expression patterns that inhibit an effective anti-tumoral response through immune exclusion and induce intrahepatic spread.

Hypoalbuminemia Is a Hepatocellular Carcinoma Independent Risk Factor for Tumor Progression in Low-Risk Bridge to Transplant Candidates.

Due to active hepatocellular carcinoma (HCC) surveillance, many patients are diagnosed with early-stage disease and are usually amendable to curative treatments. These patients lack poor prognostic factors associated with Milan Criteria and alpha fetoprotein (AFP) biomarker levels. There are currently limited strategies to assess prognosis in the patients who remain at risk of post-treatment HCC progression. In a cohort of liver transplant (LT) candidates with HCC, this study seeks to identify factors prior to liver-directed therapy (LDT) associated with time to progression (TTP). This is a retrospective analysis of prospectively collected data from LT candidates with recently diagnosed HCC and receiving LDT as a bridge to LT at three interventional oncology programs within a single system (n = 373). Demographics, clinical hepatology and serology, and factors related to HCC burden were extracted and analyzed for associations with TTP risk. Albumin level below the cohort median (3.4 g/dL) emerged as an independent risk factor for TTP controlling for AFP > 20 ng/mL as well as Milan, T-stage, and Barcelona Clinic Liver Cancer (BCLC) stage individually. In modality-specific subgroup survival analysis, albumin-based TTP stratification was restricted to patients receiving first cycle microwave ablation (p = 0.007). In n = 162 patients matching all low-risk criteria for Milan, T-stage, BCLC stage, and AFP, the effect of albumin < 3.4 g/dL remained significant for TTP (p = 0.004) with 2-year TTP rates of 68% (<3.4 g/dL) compared to 95% (≥3.4 g/dL). In optimal bridge to LT candidates with small HCC and low AFP biomarker levels, albumin level at treatment baseline provides an HCC-independent positive prognostic factor for risk of HCC progression prior to LT.

Impaired Autophagy Response in Hepatocellular Carcinomas Enriches Glypican-3 in Exosomes, Not in the Microvesicles.

Background and Aim: HCC development in liver cirrhosis is associated with impaired autophagy leading to increased production of extracellular vesicles (EVs) including exosomes and microvesicles. The goal of the study is to determine which of these particles is primarily involved in releasing of HCC-specific biomarker glypican-3 (GPC3) when autophagy is impaired. Methods: Streptavidin-coated magnetic beads were coupled with either biotinylated CD63 or Annexin A1 antibodies. Coupled beads were incubated with EVs isolated from either HCC culture or serum. EVs captured by immuno-magnetic beads were then stained with FITC or PE fluorescent-conjugated antibodies targeting exosomes (CD81), and microvesicles (ARF6). The percentage of GPC3 enrichment in the microvesicles and exosomes was quantified by flow cytometry. The impact of autophagy modulation on GPC3 enrichment in exosomes and microvesicles was assessed by treating cells with Torin 1 and Bafilomycin A1. For clinical validation, GPC3 content was quantified in microvesicles, and exosomes were isolated from the serum of patients with a recent HCC diagnosis. Results: The immune-magnetic bead assay distinguishes membrane-derived microvesicles from endosome-derived exosomes. The GPC3 expression was only seen in the CD63 beads group but not in the Annexin A1 beads group, confirming that in HCC, GPC3 is preferentially released through exosomes. Furthermore, we found that autophagy induction by Torin1 decreased GPC3-positive exosome secretion and decreased microvesicle release. Conversely, autophagy inhibition by Bafilomycin A1 increased the secretion of GPC3-positive exosomes. Serum analysis showed CD81+ve EVs were detected in exosomes and ARF6+ve vesicles were detected in microvesicles, suggesting that immunoaffinity assay is specific. The exosomal GPC3 enrichment was confirmed in isolated EVs from the serum of patients with HCC. The frequency of GPC3-positive exosomes was higher in patients with HCC (12.4%) compared to exosomes isolated from non-cirrhotic and healthy controls (3.7% and 1.3% respectively, p<0.001). Conclusion: Our results show that GPC3 is enriched in the endolysosomal compartment and released in exosome fractions when autophagy is impaired.

Radical-containing particles activate dendritic cells and enhance Th17 inflammation in a mouse model of asthma.

We identified a previously unrecognized component of airborne particulate matter (PM) formed in combustion and thermal processes, namely, environmentally persistent free radicals (EPFRs). The pulmonary health effects of EPFRs are currently unknown. In the present study, we used a model EPFR-containing pollutant-particle system referred to as MCP230. We evaluated the effects of MCP230 on the phenotype and function of bone marrow-derived dendritic cells (BMDCs) in vitro and lung dendritic cells (DCs) in vivo, and the subsequent T-cell response. We also investigated the adjuvant role of MCP230 on airway inflammation in a mouse model of asthma. MCP230 decreased intracellular reduced glutathione (GSH) and the GSH/oxidized glutathione ratio in BMDCs, and up-regulated the expression of costimulatory molecules CD80 and CD86 on DCs. The maturation of DCs was blocked by inhibiting oxidative stress or the uptake of MCP230. BMDCs exposed to MCP230 increased their antigen-specific T-cell proliferation in vitro. In a model of asthma, exposure to MCP230 exacerbated pulmonary inflammation, which was attributed to the increase of neutrophils and macrophages but not eosinophils. This result correlated with an increase in Th17 cells and cytokines, compared with non-MCP230-treated but ovalbumin (OVA)-challenged mice. The percentage of Th2 cells was comparable between OVA and OVA + MCP230 mice. Our data demonstrate that combustion-generated, EPFR-containing PM directly induced the maturation of DCs in an uptake-dependent and oxidative stress-dependent manner. Furthermore, EPFR-containing PM induced a Th17-biased phenotype in lung, accompanied by significant pulmonary neutrophilia. Exposure to EPFR-containing PM may constitute an important and unrecognized risk factor in the exacerbation and development of a severe asthma phenotype in humans.

Scaffold Sheet Design Strategy for Soft Tissue Engineering.

Creating heterogeneous tissue constructs with an even cell distribution and robust mechanical strength remain important challenges to the success of in vivo tissue engineering. To address these issues, we are developing a scaffold sheet tissue engineering strategy consisting of thin (∼200 µm), strong, elastic, and porous crosslinked urethane-doped polyester (CUPE) scaffold sheets that are bonded together chemically or through cell culture. Suture retention of the tissue constructs (four sheets) fabricated by the scaffold sheet tissue engineering strategy is close to the surgical requirement (1.8 N) rendering their potential for immediate implantation without a need for long cell culture times. Cell culture results using 3T3 fibroblasts show that the scaffold sheets are bonded into a tissue construct via the extracellular matrix produced by the cells after 2 weeks of in vitro cell culture.