Liver Xenografts Research Articles

MicroRNA-30b Suppresses Epithelial-Mesenchymal Transition and Metastasis of Hepatoma Cells

Epithelial-mesenchymal transition (EMT) is critical for induction of invasiveness and metastasis in HCC. Growing evidence indicates that upregulation of Snail, the major EMT inducer, significantly correlates with the metastasis and poor prognosis of HCC. Here, we investigate the underlying mechanism of miR-30b in suppressing metastasis of hepatoma cells by targeting Snail. In this study, we found that miR-30b was significantly downregulated and negatively associated with Snail production in HCC cell lines with higher metastatic potentials. Gain- and loss-of-function studies revealed that miR-30b could dramatically inhibit in vitro HCC cell migration and invasion. In vivo orthotopic liver xenograft model further demonstrated that stable over-expression of miR-30b significantly repressed the local invasion and lung metastasis of hepatoma cells. Meanwhile, the restoration of miR-30b expression suppressed the distant colonization of hepatoma cells. Both gain- and loss-of-function studies showed that miR-30b suppressed the EMT of hepatoma cells as indicated by the morphology changes and deregulation of epithelial and mesenchymal markers. Using RNAi, we further investigated the role of Snail in HCC cell EMT and demonstrated that knockdown of Snail significantly inhibited the EMT and cancer cell metastasis. Additionally, miR-30b exhibited inhibitory effects on HCC cell proliferation in vitro and in vivo. In conclusion, our findings highlight the significance of miR-30b downregulation in HCC tumor metastasis and invasiveness, and implicate a new potential therapeutic target for HCC metastasis. J. Cell. Physiol. 232: 625-634, 2017. © 2016 Wiley Periodicals, Inc.

Integrity of lipid nanocarriers in bloodstream and tumor quantified by near-infrared ratiometric FRET imaging in living mice

Lipid nanocarriers are considered as promising candidates for drug delivery and cancer targeting because of their low toxicity, biodegradability and capacity to encapsulate drugs and/or contrasting agents. However, their biomedical applications are currently limited because of a poor understanding of their integrity in vivo. To address this problem, we report on fluorescent nano-emulsion droplets of 100nm size encapsulating lipophilic near-infrared cyanine 5.5 and 7.5 dyes with a help of bulky hydrophobic counterion tetraphenylborate. Excellent brightness and efficient Förster Resonance Energy Transfer (FRET) inside lipid NCs enabled for the first time quantitative fluorescence ratiometric imaging of NCs integrity directly in the blood circulation, liver and tumor xenografts of living mice using a whole-animal imaging set-up. This unique methodology revealed that the integrity of our FRET NCs in the blood circulation of healthy mice is preserved at 93% at 6h of post-administration, while it drops to 66% in the liver (half-life is 8.2h). Moreover, these NCs show fast and efficient accumulation in tumors, where they enter in nearly intact form (77% integrity at 2h) before losing their integrity to 40% at 6h (half-life is 4.4h). Thus, we propose a simple and robust methodology based on ratiometric FRET imaging in vivo to evaluate quantitatively nanocarrier integrity in small animals. We also demonstrate that nano-emulsion droplets are remarkably stable nano-objects that remain nearly intact in the blood circulation and release their content mainly after entering tumors.

A Slow Maturation Process Renders Hepatitis B Virus Infectious.

Hepatitis B virus (HBV) replication is strictly limited to the liver. Virions attach to hepatocytes through interactions of the viral PreS envelope protein domain with heparan sulfate proteoglycans (HSPGs). However, HSPG is ubiquitously present on many cell types, suggesting that HBV employs mechanisms to avoid attachment at extrahepatic sites. We demonstrate that HBV particles are released from cells in an inactive form with PreS hidden in the interior. These HSPG-non-binding (N-type) particles develop receptor binding competence by translocating PreS across the envelope onto their surface. Conversion into HSPG-binding (B-type) particles occurs spontaneously and renders HBV infectious. Low-dose inoculation of mice with human liver xenografts demonstrates superiority of N-type particles in establishing infections, while mature B-type virions, generated via N-type conversion, are profoundly impaired, correlating with non-selective accumulation in extrahepatic tissues. This dynamic topology switch represents a maturation process utilized by HBV to most likely avoid non-productive docking outside the liver.

Melittin-MIL-2 fusion protein as a candidate for cancer immunotherapy.

BackgroundCytokine fusion protein that modulates the immune response holds great potential for cancer immunotherapy. IL-2 is an effective treatment against advanced cancers. However, the therapeutic efficacy of IL-2 is limited by severe systemic toxicity. Several mutants recombinant IL-2 can increase antitumor activity and minimize systemic toxicity. Melittin is an attractive anticancer candidate because of its wide-spectrum lytic properties. We previously generated a bifunctional fusion protein melittin-MIL-2, composed of melittin and a mutant IL-2. The melittin-MIL-2 inhibited the growth of human ovarian cancer SKOV3 cells in vitro and in vivo tumor growth. However, whether this antitumor effect could also be used in cancer immunotherapy was unknown. To assess its cancer immunotherapy potential, we further investigated its more effective antitumor immune response and antitumor effect against cancers of different tissue origins in vitro and in vivo.MethodsThe specific IL-2 activity of the melittin-MIL-2 fusion protein was tested on the cytokine growth dependent cell line CTLL-2. The cytolytic activity was detected by standard 4-h 51Cr-release assays. PBMC stimulation in response to the melittin-MIL-2 was determined by IFN-γ release assay. We observed the cancer cell proliferation of different tissue origins by MTT assay. The ability of melittin-MIL-2 to inhibit tumor growth in vivo was evaluated by using human liver (SMMC-7721 cancer cells), lung (A549 cancer cells) and ovarian (SKOV3 cancer cells) cancer xenograft models. To assess the immunity within the tumor microenvironment, the level of some cytokines including IFN-γ, TNF-α, IL-12 and IL-4 was analyzed by ELISA. We injected the MDA-MB-231 cells and the melittin-MIL-2 into mice, and the anti-metastatic effect was examined by counting nodules in the lung.ResultsThe melittin-MIL-2 was more effective in inducing T cell and NK-cell cytotoxicity. The fusion protein significantly increased IFN-γ production in PBMCs. In vitro, the melittin-MIL-2 mediated immune cells killing or directly killed the cancer cell lines of different tissue origins. In vivo, the fusion protein exhibited stronger inhibition on the growth of transplanted human tumors compared to rIL-2. The melittin-MIL-2 treatment promoted the IFN-γ secretion in tumor tissues and decreased the immunosuppressive cells in vivo. Furthermore, the fusion protein reduced lung metastasis of breast cancer.ConclusionsThis study provides the evidence that the melittin-MIL-2 can produce stronger immune stimulation and antitumor effects, and the fusion protein is a potent candidate for cancer immunotherapy.

Effects of Anti-repulsive Guidance Molecule C (RGMc/Hemojuvelin) Antibody on Hepcidin and Iron in Mouse Liver and Tumor Xenografts.

Hepcidin is a peptide hormone produced by the liver that regulates systemic iron homeostasis. Hepcidin is also synthesized by tumors, where it contributes to tumor growth by increasing the tumoral retention of iron. Targeted reduction of hepcidin may therefore be useful in reducing tumor growth. H5F9-AM8 is an antibody in preclinical development for the anemia of chronic disease that reduces hepcidin synthesis by binding to RGMc, a co-receptor involved in the transcriptional induction of hepcidin by BMP6. We explored the ability of H5F9-AM8 to act as an anti-tumor agent. Effects of anti-hemojuvelin antibody on hepcidin synthesis were assessed by qRTPCR in tissue culture and in tumor xenografts and livers of mice treated with H5F9-AM8 or saline. Tumor growth was assessed using caliper measurements. Serum iron was measured colorimetrically and tissue iron was measured using western blotting and inductively coupled mass spectrometry. In tissue culture, the anti-hemojuvelin antibody H5F9-AM8 significantly reduced BMP6-stimulated hepcidin synthesis in HepG2 and other cancer cells. In mice, H5F9-AM8 reduced hepcidin in the liver and increased serum iron, total liver iron, and liver ferritin. Although hepcidin in tumors was also significantly decreased, H5F9-AM8 did not reduce tumor iron content, ferritin, or tumor growth. Anti-hemojuvelin antibody successfully reduces hepcidin in both tumors and livers but has different effects in these target organs: it reduces iron content and ferritin in the liver, but does not reduce iron content or ferritin in tumors, and does not inhibit tumor growth. These results suggest that despite their ability to induce hepcidin in tumors, the anti-tumor efficacy of systemic, non-targeted hepcidin antagonists may be limited by their ability to simultaneously elevate plasma iron. Tumor-specific hepcidin inhibitors may be required to overcome the limitations of drugs that target the synthesis of both systemic and tumor hepcidin.

Efficient and Targeted Transduction of Nonhuman Primate Liver With Systemically Delivered Optimized AAV3B Vectors

Recombinant adeno-associated virus serotype 3B (rAAV3B) can transduce cultured human liver cancer cells and primary human hepatocytes efficiently. Serine (S)- and threonine (T)-directed capsid modifications further augment its transduction efficiency. Systemically delivered capsid-optimized rAAV3B vectors can specifically target cancer cells in a human liver cancer xenograft model, suggesting their potential use for human liver-directed gene therapy. Here, we compared transduction efficiencies of AAV3B and AAV8 vectors in cultured primary human hepatocytes and cancer cells as well as in human and mouse hepatocytes in a human liver xenograft NSG-PiZ mouse model. We also examined the safety and transduction efficacy of wild-type (WT) and capsid-optimized rAAV3B in the livers of nonhuman primates (NHPs). Intravenously delivered S663V+T492V (ST)-modified self-complementary (sc) AAV3B-EGFP vectors led to liver-targeted robust enhanced green fluorescence protein (EGFP) expression in NHPs without apparent hepatotoxicity. Intravenous injections of both WT and ST-modified rAAV3B.ST-rhCG vectors also generated stable super-physiological levels of rhesus chorionic gonadotropin (rhCG) in NHPs. The vector genome predominantly targeted the liver. Clinical chemistry and histopathology examinations showed no apparent vector-related toxicity. Our studies should be important and informative for clinical development of optimized AAV3B vectors for human liver-directed gene therapy.

Impact of MET targeting on tumor-associated angiogenesis and growth of MET mutations-driven models of liver cancer

Deregulated expression of the MET receptor tyrosine kinase has been reported in up to 50% of patients with hepatocellular carcinoma, the most abundant form of liver cancers, and is associated with decreased survival. Consequently, MET is considered as a molecular target in this malignancy, whose progression is highly dependent on extensive angiogenesis. Here we studied the impact of MET small molecule inhibitors on angiogenesis-associated parameters and growth of xenograft liver models consisting of cells expressing MET-mutated variants M1268T and Y1248H, which exhibit constitutive kinase activity. We demonstrate that MET mutations expression is associated with significantly increased production of vascular endothelial growth factor, which is blocked by MET targeting only in cells expressing the M1268T inhibitor-sensitive but not in the Y1248H inhibitor-resistant variant. Decrease in vascular endothelial growth factor production is also associated with reduction of tyrosine phopshorylation of the vascular endothelial growth factor receptor 2 expressed on primary liver sinusoidal endothelial cells and with inhibition of vessel formation. Furthermore, MET inhibition demonstrated an efficient anti-tumor activity and considerable reduction in microvessel density only against the M1268T-derived intrahepatic tumors. Collectively, our data support the role of targeting MET-associated angiogenesis as a major biological determinant for liver tumor growth control.

Novel Aurora/vascular endothelial growth factor receptor dual kinase inhibitor as treatment for hepatocellular carcinoma.

We previously identified Aurora B kinase as the only independent factor predictive of the aggressive recurrence of hepatocellular carcinoma (HCC). In this preclinical study, JNJ-28841072, a novel Aurora/vascular endothelial growth factor receptor dual kinase inhibitor, was evaluated for treatment of HCC. In vitro and in vivo effects of JNJ-28841072 were analyzed using human HCC cell cultures and xenograft models. An orthotopic liver xenograft model was used for the pharmacobiological effects on Aurora kinase and vascularization in hepatic tumors. JNJ-28841072 suppressed in vitro phosphorylation of histone H3 with induction of cell polyploidy and death in a dose-dependent manner (IC50 = 0.8–1.2 μM). In s.c. human HCC xenografts, remarkable inhibition of tumor growth was observed after JNJ-28841072 treatment (P = 0.0005). In orthotopic liver xenografts, the treatment with JNJ-28841072 significantly suppressed in vivo phosphorylation of histone H3 (P = 0.0008), vessel formation (P = 0.018), normoxic area (P = 0.0001), and hepatoma growth (P = 0.038). Our preclinical studies indicate that JNJ-28841072 is a promising novel therapeutic approach for the treatment of HCC. It might be worthy of evaluation in further studies.

705. Selective Advantage of Hepatocytes Expressing Wild-Type Alpha-1 Antitrypsin (AAT) in a Novel Human Liver Xenograft Model: A Model for Correction of a Gain-Of-Function Mutation

Hepatocytes play a central role in energy metabolism and secretion of plasma proteins and represent an important target for gene therapy of single gene disorders. Alpha-1 antitrypsin (AAT) deficiency is one such disorder, in which one common missense mutation (E342K, known as the PI*Z allele) results in impaired secretion of AAT. In the majority of patients with AAT deficiency, this causes a lung disease due to a lack of the normal AAT-mediated protection of lung elastin from neutrophil elastase. In a subset of patients, accumulation of Z-mutant AAT protein triggers hepatocyte injury leading to inflammation and cirrhosis. As vector-mediated methods for correction of these two defects have been developed for both in vivo and ex vivo use, we sought to determine whether correction of the Z-mutant defect in hepatocytes might confer a selective advantage for repopulation of hepatocytes within an intact liver. To test this concept, a transgenic mouse strain expressing a human PI*Z allele was crossed with the NOD-SCID-gamma chain knockout (NSG) strain to create a recipient strain (PI*Z-NSG) for human hepatocyte xenotransplantation. Initial comparisons indicated that PI*Z-NSG recipients support more efficient engraftment of normal (wt-AAT) human primary hepatocytes as compared with NSG recipients. A number of procedures to optimize primary hepatocyte engraftment, and pretreatment of the recipient with monocrotaline further accentuated the level of engraftment. Finally, we propose to test the paradigm of using the selective advantage of wt-AAT hepatocytes to model gene and cell therapy of AAT deficiency, through the introduction of a dual-function lentivirus vector expressing both a myc-tagged wild-type AAT and a synthetic miRNA to knockdown the endogenous allele. The NSG-PI*Z recipient strain could be used as a platform for future studies of both cell-based and genetic therapies of AAT deficiency and further could predict a selective advantage of corrected cells in AAT deficient patients. In addition this new liver xenograft model provides a setting in which to easily a reproducibly repopulate a mouse liver with human hepatocytes.

Control of temporal activation of hepatitis C virus-induced interferon response by domain 2 of nonstructural protein 5A

Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a multifunctional protein playing a crucial role in diverse steps of the viral replication cycle and perturbing multiple host cell pathways. We showed previously that removal of a region in domain 2 (D2) of NS5A (mutant NS5A(D2Δ)) is dispensable for viral replication in hepatoma cell lines. By using a mouse model and immune-competent cell systems, we studied the role of D2 in controlling the innate immune response. In vivo replication competence of NS5A(D2Δ) was studied in transgenic mice with human liver xenografts. Results were validated using primary human hepatocytes (PHHs) and mechanistic analyses were conducted in engineered Huh7 hepatoma cells with reconstituted innate signaling pathways. Although the deletion in NS5A removed most of the interferon (IFN) sensitivity determining-region, mutant NS5A(D2Δ) was as sensitive as the wild type to IFN-α and IFN-λ in vitro, but severely attenuated in vivo. This attenuation could be recapitulated in PHHs and was linked to higher activation of the IFN response, concomitant with reduced viral replication and virus production. Importantly, immune-reconstituted Huh7-derived cell lines revealed a sequential activation of the IFN-response via RIG-I (retinoic acid-inducible gene I) and MDA5 (Myeloma differentiation associated factor 5), respectively, that was significantly higher in the case of the mutant lacking most of NS5A D2. Our study reveals an important role of NS5A D2 for suppression of the IFN response that is activated by HCV via RIG-I and MDA5 in a sequential manner.

Xenotransplantation literature update, November–December 2014

Xenotransplantation literature update, <scp>N</scp>ovember–<scp>D</scp>ecember 2014

Abstract 220: Preclinical studies of EpCAM-targeted therapy for human hepatocellular carcinoma with specific inhibition of stem cell features

Abstract Hepatocellular carcinoma (HCC) is known to demonstrate a morphological variety of macroscopic appearances, but their pathological and molecular differences remain unclear. First, the clinicopathologic characteristics as well as genome-wide gene expressions were analyzed in relation to the gross morphology of HCC. Among the patients with nodular type HCC, significantly poor prognosis was recognized in confluent multinodular (CM) type in overall survival as well as recurrence-free survival. Analysis of the genome-wide expression patterns revealed significant deference of CM-type HCC from other types of HCC. In particular, a stem cell marker EpCAM was dominantly expressed in CM-type HCC. Next, the effects of VB4-845, an immunotoxin targeting EpCAM, were evaluated in HCC. In vitro effects of VB4-845 on human HCC cells, the cytotoxic activity, sphere-forming ability, and expression of hepatic stem/progenitor markers were analyzed. In vivo effects of VB4-845 were evaluated using subcutaneous and orthotopic liver xenograft models. In all HCC cell lines expressing EpCAM, VB4-845 showed potent cytotoxicity and was significantly effective in combination with 5-FU. Although 5-FU did not affect the sphere-forming ability and increased the populations expressing other stem/progenitor markers CD133 and CD13, VB4-845 strongly suppressed the sphere-formation and decreased the population expressing CD133 and CD13. In subcutaneous xenograft models, the combination of VB4-845 plus 5-FU showed significant regression of tumors compared with the control. Moreover, in orthotopic liver xenograft models, the combination therapy dramatically decreased the tumor volume compared with the control. Our preclinical investigation suggests that EpCAM-targeted therapy may offer a promising and specific approach for the treatment of HCC with the poor prognostic phenotype. Citation Format: Shinji Tanaka, Kousuke Ogawa, Ayano Murakata, Kaoru Mogushi, Satoshi Matsumura, Arihiro Aihara, Daisuke Ban, Takanori Ochiai, Takumi Irie, Atsushi Kudo, Noriaki Nakamura, Hiroshi Tanaka, Shigeki Arii, Minoru Tanabe. Preclinical studies of EpCAM-targeted therapy for human hepatocellular carcinoma with specific inhibition of stem cell features. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 220. doi:10.1158/1538-7445.AM2014-220

A novel small-molecule activator of procaspase-3 induces apoptosis in cancer cells and reduces tumor growth in human breast, liver and gallbladder cancer xenografts

Purpose: Procaspase-3, a proenzyme of apoptotic executioner caspase-3, is overexpressed in numerous tumors. We aimed to characterize a novel procaspase-3 activator, WF-210, which may have potential as an anticancer drug.Experimental design: The procaspase-3 activating ability, antitumor efficacy, mechanisms of action, and toxicity profiles of WF-210 were investigated in vitro and in vivo, using normal cells, cancer cells, and mouse xenograft models. The role of procaspase-3 in WF-210-induced apoptosis was explored by manipulating procaspase-3 expression in cultured cells.Results: WF-210 activated procaspase-3 with an EC50 of 0.95 μM, less than half that of its mother compound PAC-1 (2.08 μM). The mechanism involved the chelation of inhibitory zinc ions, subsequently resulting in an auto-activation of procaspase-3. WF-210 was more cytotoxic than PAC-1 to human cancer cells, but less cytotoxic to normal cells. Cancer cells with high procaspase-3 expression, like HL-60 and U-937, were particularly sensitive. WF-210-induced the apoptosis of HL-60 and U-937 cells by activating procaspases and promoting proteasome-dependent degradation of XIAP and Survivin. The level of WF-210-induced apoptosis in cultured cells was related to the level of procaspase-3 expression. Finally, WF-210 was superior to PAC-1 in retarding the in vivo growth of breast, liver and gallbladder xenograft tumors which overexpress procaspase-3, and induced no substantial weight loss or neurotoxicity. WF-210 and PAC-1 had no effect on the growth of MCF-7 xenograft tumors, which do not express procaspase-3.Conclusion: We identified WF-210 as a potent small-molecule activator of procaspase-3. The favorable antitumor activity and acceptable toxicity profile of WF-210 provide a strong rationale for its clinical evaluation in the treatment of tumors with high procaspase-3 expression.

Pig-to-Baboon Liver Xenoperfusion Utilizing GalTKO.hCD46 Pigs and Glycoprotein Ib Blockade.

Although transplantation of genetically-modified porcine livers into baboons has yielded recipient survival for up to 7 days, survival is limited by profound thrombocytopenia, which becomes manifest almost immediately after revascularization, and by subsequent coagulopathy. Porcine von Willebrand's factor (VWF), a glycoprotein that adheres to activated platelets to initiate thrombus formation, has been shown to constitutively activate human platelets via their glycoprotein Ib (GPIb) receptors. Here we report our pig-to-primate liver xenoperfusion model and evaluate whether targeting the GPIb-VWF axis prevents platelet sequestration. Methods: 12 baboons underwent cross-circulation with the following extracorporeal livers: one allogeneic control with a baboon liver, 4 xenogeneic controls with a GalTKO.hCD46 pig liver, 3 GalTKO.hCD46 pig livers in recipients treated with αGPIb antibody during perfusion, and 4 GalTKO.hCD46 pig livers pretreated with DDAVP in recipients treated with αGPIb antibody during perfusion. Results: All perfused livers appeared grossly and macroscopically normal, and produced bile. Xenograft liver perfusion experiments treated with αGPIb antibody may show less platelet sequestration during the initial two hours of perfusion. Portal venous resistance remained constant in all perfusion experiments. Platelet activation studies demonstrated platelet activation in all xenoperfusions, but not in the allogeneic perfusion. Conclusion: These observations suggest that primate platelet sequestration by porcine liver and the associated thrombocytopenia are multifactorial, and perhaps partially mediated by a constitutive interaction between porcine VWF and the primate GPIb receptor. Control of platelet sequestration and consumptive coagulopathy in liver xenotransplantation will likely require a multi-faceted approach in our clinically relevant perfusion model. DISCLOSURES:Ayares, D.: Employee, Revivicor. Pierson III, R.: Grant/Research Support, Revivicor.

Pig‐to‐baboon liver xenoperfusion utilizing GalTKO.hCD46 pigs and glycoprotein Ib blockade

Although transplantation of genetically modified porcine livers into baboons has yielded recipient survival for up to 7days, survival is limited by profound thrombocytopenia, which becomes manifest almost immediately after revascularization, and by subsequent coagulopathy. Porcine von Willebrand's factor (VWF), a glycoprotein that adheres to activated platelets to initiate thrombus formation, has been shown to constitutively activate human platelets via their glycoprotein Ib (GPIb) receptors. Here, we report our pig-to-primate liver xenoperfusion model and evaluate whether targeting the GPIb-VWF axis prevents platelet sequestration. Twelve baboons underwent cross-circulation with the following extracorporeal livers: one allogeneic control with a baboon liver, 4 xenogeneic controls with a GalTKO.hCD46 pig liver, 3 GalTKO.hCD46 pig livers in recipients treated with αGPIb antibody during perfusion, and 4 GalTKO.hCD46 pig livers pre-treated with D-arginine vasopressin (DDAVP) in recipients treated with αGPIb antibody during perfusion. All perfused livers appeared grossly and macroscopically normal and produced bile. Xenograft liver perfusion experiments treated with αGPIb antibody may show less platelet sequestration during the initial 2h of perfusion. Portal venous resistance remained constant in all perfusion experiments. Platelet activation studies demonstrated platelet activation in all xenoperfusions, but not in the allogeneic perfusion. These observations suggest that primate platelet sequestration by porcine liver and the associated thrombocytopenia are multifactorial and perhaps partially mediated by a constitutive interaction between porcine VWF and the primate GPIb receptor. Control of platelet sequestration and consumptive coagulopathy in liver xenotransplantation will likely require a multifaceted approach in our clinically relevant perfusion model.

10:12 AM Abstract No. 2 - Novel molecular targeting of Necl 5 to prevent intimal hyperplasia and restenosis

10:12 AM Abstract No. 2 - Novel molecular targeting of Necl 5 to prevent intimal hyperplasia and restenosis

Numerical Comparison of Iodine-Based and Indium-Based Antibody Biodistributions

Single-step iodination is often performed in preference to use of a radiometal label for initial animal biodistributions. Yet loss of iodine occurs in vivo so that it is important to measure uptake (%ID/g) differences between radiolabels. Murine biodistributions of four radioiodinated and (111)In-labeled cognate anti-carcinoembryonic antigen antibodies were compared. Uptakes were obtained in athymic mice out to 96 hours for diabody, minibody, scFv-Fc, and intact humanized (M5A) versions of the T84.66 antibody. Tissues included liver, spleen, kidneys, lungs, and human LS174T colorectal xenografts. Ratios (R) of iodine uptake to indium uptake were calculated. For all cognates, no significant differences were found in the blood uptakes between the two labels. In normal solid organs, iodine was generally cleared more rapidly with decreasing molecular weight (MW). In liver and spleen by 24 hours, the R value was 5% for diabody and minibody, whereas a value of 50% was seen for the intact mAb. Renal differences were even more marked for the two lower MW species. Tumor losses, however, were found to be essentially independent of MW and were modest; 50% by 48 hours. To test the generality of the results, comparisons were then made for normal organs and tumors of the R values found above for M5A and MN-14 intact antibody literature results. Good agreement, within estimated errors in R, was seen between these two cases, although (111)In and (88)Y were the respective radiometals. Loss of iodine from labeled antibodies can be marked in normal organs and that correction (by 1/R) of the iodine biodistribution to estimate the associated radiometal result may be possible. Explicit differences between the two types of biodistribution also imply that separate uptake results need to be considered when evaluating the impact on imaging and therapy using various possible radiolabels.

AAV shuffles to the liver: commentary on Lisowski et al.

AAV shuffles to the liver: commentary on Lisowski et al.

EpCAM-Targeted Therapy for Human Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies and the identification of new effective therapies for HCC is urgently needed. We have previously identified EpCAM, one of the hepatic stem/progenitor markers, as a prognostic predictor of patients who received curative hepatectomy for HCC. In this preclinical study, the effects of VB4-845, an immunotoxin targeting EpCAM, were evaluated in HCC. In vitro effects of VB4-845 on human HCC cells, the cytotoxic activity, sphere-forming ability, and expression of hepatic stem/progenitor markers were analyzed. In vivo effects of VB4-845 were evaluated using subcutaneous and orthotopic liver xenograft models. In all HCC cell lines expressing EpCAM, VB4-845 showed potent cytotoxicity and was significantly effective in combination with 5-FU (p < 0.05). Although 5-FU did not affect the sphere-forming ability and increased the populations expressing other stem/progenitor markers CD133 and CD13 (p < 0.05), VB4-845 strongly suppressed the sphere-formation and decreased the population expressing CD133 and CD13 (p < 0.0005, <0.01, respectively). In subcutaneous xenograft models, the combination of VB4-845 plus 5-FU showed significant regression of tumors compared with the control (p = 0.016). Moreover, in orthotopic liver xenograft models, the combination therapy dramatically decreased the tumor volume compared with the control (p = 0.0011). Our preclinical investigation suggests that EpCAM-targeted therapy may offer a promising and novel approach for the treatment of HCC with a poorer prognosis.

MicroRNA-148a suppresses the epithelial–mesenchymal transition and metastasis of hepatoma cells by targeting Met/Snail signaling

Metastasis is responsible for the rapid recurrence and poor survival of malignancies. Epithelial-mesenchymal transition (EMT) has a critical role in metastasis. Increasing evidence indicates that EMT can be regulated by microRNAs (miRNAs). miR-148a is a liver-abundant miRNA. However, the role of miR-148a in the development of liver cancer remains largely unknown. In this study, we found that, compared with normal livers, miR-148a was significantly decreased in hepatocellular carcinoma (HCC) tissues, especially in those with the portal vein tumor thrombus. An in vitro transwell assay and an in vivo orthotopic liver xenograft model showed that the restoration of miR-148a expression significantly repressed the migration and pulmonary metastasis of hepatoma cells. Linear regression analysis revealed a positive correlation between the expression of miR-148a and the mRNA level of E-cadherin gene in human HCC tissues. Both gain- and loss-of-function studies disclosed that miR-148a promoted the expression of epithelial marker (E-cadherin) and reduced the levels of mesenchymal markers (N-cadherin, fibronectin or vimentin) in hepatoma cells. These data suggest that miR-148a may suppress EMT and cancer metastasis. Further mechanistic investigations showed that miR-148a directly inhibited Met expression by binding to its 3'-UTR. Moreover, the reintroduction of miR-148a attenuated the downstream signaling of Met, like activated phosphorylation of AKT-Ser473 and inhibitory phosphorylation of GSK-3β-Ser9, and consequently reduced the nuclear accumulation of Snail, a transcription factor that promotes EMT. Taken together, miR-148a may negatively regulate Met/Snail signaling and therefore inhibit the EMT and metastasis of hepatoma cells. These findings highlight the significance of miR-148a downregulation in tumor progression and implicate miR-148a as an attractive candidate for cancer therapy.