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A recent systematic sequence analysis of well-annotated human protein coding genes or consensus coding sequences led to the identification of 189 genes displaying somatic mutations in breast and colorectal cancers. Based on their mutation prevalence, a subset of these genes was identified as cancer candidate (CAN) genes as they could be potentially involved in cancer. We evaluated the mutational profiles of 19 CAN genes in the highly aggressive tumors: glioblastoma, melanoma, and pancreatic carcinoma. Among other changes, we found novel somatic mutations in EPHA3, MLL3, TECTA, FBXW7, and OBSCN, affecting amino acids not previously found to be mutated in human cancers. Interestingly, we also found a germline nucleotide variant of OBSCN that was previously reported as a somatic mutation. Our results identify specific genetic lesions in glioblastoma, melanoma, and pancreatic cancers and indicate that CAN genes and their mutational profiles are tumor specific. Some of the mutated genes, such as the tyrosine kinase EPHA3, are clearly amenable to pharmacologic intervention and could represent novel therapeutic targets for these incurable cancers. We also speculate that similar to other oncogenes and tumor suppressor genes, mutations affecting OBSCN could be involved in cancer predisposition. [Cancer Res 2007;67(8):3545–50]

Supplementary Table 1 from Novel Somatic and Germline Mutations in Cancer Candidate Genes in Glioblastoma, Melanoma, and Pancreatic Carcinoma

Background and aims Messenger RNA (mRNA)-based therapeutics are rapidly progressing to the clinic and hold tremendous potential for benefiting millions of people worldwide. Therapeutic targeting of injuries that require transient restoration of proteins by mRNA delivery is an attractive aspect, however until recently, it has remained poorly explored. In this study, we examined for the first time, the therapeutic utility of mRNA delivery in liver fibrosis and cirrhosis, which contributes to millions of deaths, annually. Here, we aimed to demonstrate therapeutic efficacy of the human transcription factor hepatocyte nuclear factor alpha (HNF4A) encoding mRNA in chronically injured murine liver leading to fibrosis and cirrhosis. Methods We investigated restoration of hepatocyte functions by HNF4A mRNA transfection in vitro, and analyzed the attenuation of liver fibrosis and cirrhosis in multiple mouse models, by delivering hepatocyte-targeted biodegradable lipid nanoparticles (LNP) encapsulating HNF4A mRNA. To identify potential mechanisms, we performed microarray-based gene expression profiling, single cell RNA sequencing, and chromatin immunoprecipitation. We used primary liver cells and human liver buds for additional functional validation. Results Expression of HNF4A encoding mRNA led to restoration of metabolic activity of fibrotic primary murine and human hepatocytes in vitro. Repeated in vivo delivery of HNF4A mRNA encapsulated-LNP induced a robust inhibition of fibrogenesis in four independent mouse models of hepatotoxin- and cholestasis-induced liver fibrosis. Mechanistically, we discovered that paraoxonase 1 is a direct target of HNF4A and it contributes to HNF4A-mediated attenuation of liver fibrosis via modulation of liver macrophages and hepatic stellate cells. Conclusion Collectively, our findings provide the first direct preclinical evidence of the applicability of HNF4A mRNA therapeutics for the treatment of fibrosis in the liver. Lay summary Liver fibrosis and cirrhosis remain unmet medical needs and contribute to high mortality, worldwide. Herein, we take advantage of a promising, emerging mRNA therapy approach to treat liver fibrosis and cirrhosis. We demonstrate that restoration of a key gene, HNF4A, via mRNA encapsulated in lipid nanoparticles decreased injury in multiple mouse models of fibrosis and cirrhosis. Our study provides the proof-of-concept that mRNA therapy would be a promising strategy for reversing liver fibrosis and cirrhosis.

Simple Summary Gene therapy is a novel approach to treat diseases by introducing corrective genetic information into target cells. Adeno-associated virus vectors are the most frequently applied gene delivery tools for in vivo gene therapy and are also studied as part of innovative anticancer strategies. Here, we report on the natural preference of AAV2 vectors for hepatocellular carcinoma (HCC) compared to nonmalignant liver cells in mice and human tissue. This preference in transduction is due to the improved intracellular processing of AAV2 vectors in HCC, resulting in significantly more vector genomes serving as templates for transcription in the cell nucleus. Based on this natural tropism for HCC, novel therapeutic strategies can be designed or existing therapeutic approaches can be strengthened as they currently result in only a minor improvement of the poor prognosis for most liver cancer patients. Abstract Although therapeutic options are gradually improving, the overall prognosis for patients with hepatocellular carcinoma (HCC) is still poor. Gene therapy-based strategies are developed to complement the therapeutic armamentarium, both in early and late-stage disease. For efficient delivery of transgenes with antitumor activity, vectors demonstrating preferred tumor tropism are required. Here, we report on the natural tropism of adeno-associated virus (AAV) serotype 2 vectors for HCC. When applied intravenously in transgenic HCC mouse models, similar amounts of vectors were detected in the liver and liver tumor tissue. In contrast, transduction efficiency, as indicated by the level of transgene product, was moderate in the liver but was elevated up to 19-fold in mouse tumor tissue. Preferred transduction of HCC compared to hepatocytes was confirmed in precision-cut liver slices from human patient samples. Our mechanistic studies revealed that this preference is due to the improved intracellular processing of AAV2 vectors in HCC, resulting, for example, in nearly 4-fold more AAV vector episomes that serve as templates for gene transcription. Given this background, AAV2 vectors ought to be considered to strengthen current—or develop novel—strategies for treating HCC.

ObjectiveLiver fibrosis and cirrhosis resulting from chronic liver injury represent a major healthcare burden worldwide. Growth differentiation factor (GDF) 11 has been recently investigated for its role in rejuvenation of ageing organs, but its role in chronic liver diseases has remained unknown. Here, we investigated the expression and function of GDF11 in liver fibrosis, a common feature of most chronic liver diseases.DesignWe analysed the expression of GDF11 in patients with liver fibrosis, in a mouse model of liver fibrosis and in hepatic stellate cells (HSCs) as well as in other liver cell types. The functional relevance of GDF11 in toxin-induced and cholestasis-induced mouse models of liver fibrosis was examined by in vivo modulation of Gdf11 expression using adeno-associated virus (AAV) vectors. The effect of GDF11 on leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5)+ liver progenitor cells was studied in mouse and human liver organoid culture. Furthermore, in vivo depletion of LGR5+ cells was induced by injecting AAV vectors expressing diptheria toxin A under the transcriptional control of Lgr5 promoter.ResultsWe showed that the expression of GDF11 is upregulated in patients with liver fibrosis and in experimentally induced murine liver fibrosis models. Furthermore, we found that therapeutic application of GDF11 mounts a protective response against fibrosis by increasing the number of LGR5+ progenitor cells in the liver.ConclusionCollectively, our findings uncover a protective role of GDF11 during liver fibrosis and suggest a potential application of GDF11 for the treatment of chronic liver disease.

Background & aims: Hepatocellular carcinoma (HCC) is a cancer with multiple aetiologies and widespread prevalence. Largely refractory to current treatments, HCC is the fourth leading cause of cancer-related deaths worldwide. MicroRNAs (miRNAs) are important regulators in HCCs. We aimed to identify tumour suppressor miRNAs during tumour regression in a conditional c-MYC-driven mouse model (LT2/MYC) of HCC, and to evaluate their therapeutic potential for HCC treatment. Methods: We performed miRNA expression profiling of developed and regressing LT2/MYC tumours and in-depth in vitro gain- and loss-of-function analyses. The effect of adeno-associated virus (AAV) vector-mediated miR-342-3p treatment was evaluated in 3 HCC mouse models. Results: We identified miR-342-3p as a tumour suppressor miRNA in HCC, with increased expression in regressing tumours. Forced miR-342-3p expression in hepatoma cells showed significantly decreased cell proliferation, migration, and colony formation. In vivo administration of AAV-miR-342-3p led to significant attenuation of tumour development and increased overall survival. We identified monocarboxylic acid transporter 1 (MCT1) as a bona fide target of miR-342-3p in HCC. We show that the tumour suppressor role of miR-342-3p is executed partly by modulating the lactate transport function of MCT1. Importantly, we find miR-342-3p downregulated in tumours from patients with HCC compared with matched non-tumour tissues, inversely correlating with MCT1 expression. We observed similar findings in TCGA-LIHC data. Conclusions: In our study, we identified and validated miR-342-3p as a tumour suppressor miRNA in HCC. We demonstrated its therapeutic efficacy in significantly attenuating tumour development, and prolonging survival, in different HCC mouse models. Identification of miR-342-3p as an effective tumour suppressor opens a therapeutic avenue for miRNA-mediated attenuation of HCC development. Lay summary: Hepatocellular carcinoma (HCC), the most common type of liver cancer, affects diverse populations and has a global impact, being the fourth leading cause of cancer deaths worldwide. There are currently no systemic therapies for HCC that can significantly prolong long-term survival. Thus, novel effective treatment options are urgently required. To understand the molecular basis of tumour regression, we compared tumours and regressing liver tumours in mice. We show that a small non-coding miRNA, miR-342-3p, is a tumour suppressor in HCC. Expression of miR-342-3p is low in tumours and high in regressing tumours. When miR-342-3p is delivered to mouse livers with HCC, it can significantly slow down liver tumour development and improve survival. Our study highlights the promising therapeutic potential of miR-342-3p intervention in HCC. Deutsche Krebshilfe

The ability of the liver to regenerate and restore mass limits the increasing mortality rate due to life‐threatening liver diseases. Successful liver regeneration is accomplished in multiple stages, of which the priming and proliferation phases are well studied. However, the regulatory pathways, specifically microRNA (miRNA)‐mediated posttranscriptional regulation, which prevent uncontrolled proliferation and mediate the termination of liver regeneration, are not well understood. We identified differentially regulated miRNAs during the termination phase after 2/3 partial hepatectomy (PH) in mice, which is a well‐established mouse model of liver regeneration. We further evaluated the function of differentially regulated miRNAs in primary mouse hepatocytes by using mimics and inhibitors and in vivo by using adeno‐associated virus (AAV) serotype 8. A candidate miRNA target was identified by messenger RNA array in silico analyses and validated in primary mouse and human hepatocytes. Using miRNA profiling, we discovered miR‐125b‐5p as a novel regulator of hepatocyte proliferation in the late phase of liver regeneration. AAV‐mediated miR‐125b‐5p delivery in mice enhanced the endogenous regenerative capacity and resulted in improved restoration of liver mass after 2/3 PH. Further, we found that ankyrin repeat and BTB/POZ domain containing protein 1 (Abtb1) is a direct target of miR‐125b‐5p in primary mouse and human hepatocytes and contributes to the pro‐proliferative activity of miR‐125b‐5p by forkhead box G1 (FOXG1) and the cyclin‐dependent kinase inhibitor 1A (p21) pathway. Conclusion: miR‐125b‐5p has an important role in regulating hepatocyte proliferation in the termination phase of liver regeneration and may serve as a potential therapeutic target in various liver diseases that often exhibit deregulated hepatocyte proliferation.

The last decade has witnessed significant advancements in our understanding of how small noncoding RNAs, such as microRNAs (miRNAs), regulate disease progression. One such miRNA, miR-221, has been shown to play a key role in the progression of liver fibrosis, a common feature of most liver diseases. Many reports have demonstrated the upregulation of miR-221 in liver fibrosis caused by multiple etiologies such as viral infections and nonalcoholic steatohepatitis. Inhibition of miR-221 via different strategies has shown promising results in terms of the suppression of fibrogenic gene signatures in vitro, as well as in vivo, in independent mouse models of liver fibrosis. In addition, miR-221 has also been suggested as a noninvasive serum biomarker for liver fibrosis and cirrhosis. In this review, we discuss the biology of miR-221, its significance and use as a biomarker during progression of liver fibrosis, and finally, potential and robust approaches that can be utilized to suppress liver fibrosis via inhibition of miR-221.

Summary Adeno-associated virus (AAV)-based vectors are considered efficient and safe gene delivery systems in gene therapy. We combined two guide RNA genes, Cas9, and a self-linearizing repair template in one vector (AIO-SL) to correct fumarylacetoacetate hydrolase (FAH) deficiency in mice. The vector genome of 5.73 kb was packaged into VP2-depleted AAV particles (AAV2/8ΔVP2), which, however, did not improve cargo capacity. Reprogrammed hepatocytes were treated with AIO-SL.AAV2ΔVP2 and subsequently transplanted, resulting in large clusters of FAH-positive hepatocytes. Direct injection of AIO-SL.AAV8ΔVP2 likewise led to FAH expression and long-term survival. The AIO-SL vector achieved an ∼6-fold higher degree of template integration than vectors without template self-linearization. Subsequent analysis revealed that AAV8 particles, in contrast to AAV2, incorporate oversized genomes distinctly greater than 5.2 kb. Finally, our AAV8-based vector represents a promising tool for gene editing strategies to correct monogenic liver diseases requiring (large) fragment removal and/or simultaneous sequence replacement., Graphical Abstract, Highlights • Single AAV vector mediates efficient large fragment replacement in vivo and ex vivo • Fah-corrected iHeps repopulate the liver of recipient mice • Self-linearizing donor template enhances integration rate • AAV2 and AAV8 reveal differences in packaging the oversized AIO-SL vector genome, Genetics; Techniques in Genetics; Genetic Engineering

AIM To stably correct tyrosinaemia in proliferating livers of fumarylacetoacetate-hydrolase knockout (Fah-/-) mice by homologous-recombination-mediated targeted addition of the Fah gene. METHODS C57BL/6 Fah∆exon5 mice served as an animal model for human tyrosinaemia type 1 in our study. The vector was created by amplifying human Fah cDNA including the TTR promoter from a lentivirus plasmid as described. The Fah expression cassette was flanked by homologous arms (620 bp and 749 bp long) of the Rosa26 gene locus. Mice were injected with 2.1 × 108 VP of this vector (rAAV8-ROSA26.HAL-TTR.Fah-ROSA26.HAR) via the tail vein. Mice in the control group were injected with 2.1 × 108 VP of a similar vector but missing the homologous arms (rAAV8-TTR.Fah). Primary hepatocytes from Fah-/- recipient mice, treated with our vectors, were isolated and 1 × 106 hepatocytes were transplanted into secondary Fah-/- recipient mice by injection into the spleen. Upon either vector application or hepatocyte transplantation NTBC treatment was stopped in recipient mice. RESULTS Here, we report successful HR-mediated genome editing by integration of a Fah gene expression cassette into the “safe harbour locus” Rosa26 by recombinant AAV8. Both groups of mice showed long-term survival, weight gain and FAH positive clusters as determined by immunohistochemistry analysis of liver sections in the absence of NTBC treatment. In the group of C57BL/6 Fah∆exon5 mice, which have been transplanted with hepatocytes from a mouse injected with rAAV8-ROSA26.HAL-TTR.Fah-ROSA26.HAR 156 d before, 6 out of 6 mice showed long-term survival, weight gain and FAH positive clusters without need for NTBC treatment. In contrast only 1 out 5 mice, who received hepatocytes from rAAV8-TTR.Fah treated mice, survived and showed few and smaller FAH positive clusters. These results demonstrate that homologous recombination-mediated Fah gene transfer corrects the phenotype in a mouse model of human tyrosinaemia type 1 (Fah-/- mice) and is long lasting in a proliferating state of the liver as shown by withdrawal of NTBC treatment and serial transplantation of isolated hepatocytes from primary Fah-/- recipient mice into secondary Fah-/- recipient mice. This long term therapeutic efficacy is clearly superior to our control mice treated with episomal rAAV8 gene therapy approach. CONCLUSION HR-mediated rAAV8 gene therapy provides targeted transgene integration and phenotypic correction in Fah-/- mice with superior long-term efficacy compared to episomal rAAV8 therapy in proliferating livers.

Conjugates based on nanostructured, superparamagnetic particles, a thermolabile linker and a cytotoxic maytansinoid were developed to serve as a model for tumour-selective drug delivery and release. It combines chemo- with thermal therapy. The linker-modified toxin was prepared by a combination of biotechnology and semisynthesis. Drug release was achieved by hyperthermia through an external oscillating electromagnetic field that induces heat inside the particles. Efficacy of this release concept was demonstrated both for cancer cell proliferation in vitro, and for tumour growth in vivo, in a xenograft mouse model. Biocompatibility studies for these magnetic-nanoparticle/ansamitocin conjugates complement this work.

Direct induction of induced hepatocytes (iHeps) from fibroblasts holds potential as a strategy for regenerative medicine but until now has only been shown in culture settings. Here, we describe in vivo iHep formation using transcription factor induction and genetic fate tracing in mouse models of chronic liver disease. We show that ectopic expression of the transcription factors FOXA3, GATA4, HNF1A, and HNF4A from a polycistronic lentiviral vector converts mouse myofibroblasts into cells with a hepatocyte phenotype. In vivo expression of the same set of transcription factors from a p75 neurotrophin receptor peptide (p75NTRp)-tagged adenovirus enabled the generation of hepatocyte-like cells from myofibroblasts in fibrotic mouse livers and reduced liver fibrosis. We have therefore been able to convert pro-fibrogenic myofibroblasts in the liver into hepatocyte-like cells with positive functional benefits. This direct in vivo reprogramming approach may open new avenues for the treatment of chronic liver disease.

Cholangiocarcinoma (CCA) is a cancer type with high postoperative relapse rates and poor long-term survival largely due to tumor invasion, distant metastasis, and multidrug resistance. Deregulated microRNAs (miRNAs) are implicated in several cancer types including CCA. The specific roles of the miRNA let-7c in cholangiocarcinoma are not known and need to be further elucidated. In our translational study we show that microRNA let-7c expression was significantly downregulated in human cholangiocarcinoma tissues when compared to adjacent tissues of the same patient. Let-7c inhibited the tumorigenic properties of cholangiocarcinoma cells including their self-renewal capacity and sphere formation in vitro and subcutaneous cancer cell growth in vivo. Ectopic let-7c overexpression suppressed migration and invasion capacities of cholangiocarcinoma cell lines in vitro, however, promoted distant invasiveness in vivo. Furthermore, we found that let-7c regulated the aforementioned malignant biological properties, at least in part, through regulation of EZH2 protein expression and through the DVL3/β-catenin axis. The miRNA let-7c thus plays an important dual role in regulating tumorigenic and metastatic abilities of human cholangiocarcinoma through mechanisms involving EZH2 protein and the DVL3/β-catenin axis.

Background & Aims Fibrosis, a cardinal feature of a dysfunctional liver, significantly contributes to the ever-increasing mortality due to end-stage chronic liver diseases. The crosstalk between hepatocytes and hepatic stellate cells (HSCs) plays a key role in the progression of fibrosis. Although ample efforts have been devoted to elucidate the functions of HSCs during liver fibrosis, the regulatory functions of hepatocytes remain elusive. Methods Using an unbiased functional microRNA (miRNA) screening, we investigated the ability of hepatocytes to regulate fibrosis by fine-tuning gene expression via miRNA modulation. The in vivo functional analyses were performed by inhibiting miRNA in hepatocytes using adeno-associated virus in carbon-tetrachloride- and 3,5-di-diethoxycarbonyl-1,4-dihydrocollidine-induced liver fibrosis. Results Blocking miRNA-221-3p function in hepatocytes during chronic liver injury facilitated recovery of the liver and faster resolution of the deposited extracellular matrix. Furthermore, we demonstrate that reduced secretion of C–C motif chemokine ligand 2, as a result of post-transcriptional regulation of GNAI2 (G protein alpha inhibiting activity polypeptide 2) by miRNA-221-3p, mitigates liver fibrosis. Conclusions Collectively, miRNA modulation in hepatocytes, an easy-to-target cell type in the liver, may serve as a potential therapeutic approach for liver fibrosis. Lay summary Liver fibrosis majorly contributes to mortality resulting from various liver diseases. We discovered a small RNA known as miRNA-221-3p, whose downregulation in hepatocytes results in reduced liver fibrosis. Thus, inhibition of miRNA-221-3p may serve as one of the therapeutic approaches for treatment of liver fibrosis.

Venous thromboembolism (VTE) is a complication of malignancy that is associated with significant mortality. The CLOT trial showed superiority of dalteparin in comparison to warfarin in preventing VTE recurrence. Rivaroxaban has been approved for treatment of deep venous thrombosis (DVT) and pulmonary embolism (PE). In the absence of large randomized trials in the oncology population, the efficacy and safety of rivaroxaban for the treatment of VTE in cancer patients needs to be assessed. A single-center retrospective chart review was conducted to assess the efficacy and safety of rivaroxaban compared with dalteparin in cancer-associated thrombosis. Out of 671 patients identified, 286 patients (107 in the rivaroxaban group and 179 in the dalteparin group) were eligible for analysis. The rivaroxaban group had a rate of VTE recurrence at 6 months of 4.9 versus 11.1% with dalteparin (p = 0.252). The incidence of recurrent DVT at 6 months was lower in patients treated with rivaroxaban (0%) compared with dalteparin (8.2%) at 6 months (p = 0.025). Incidence of recurrent PE in the rivaroxaban group (5%) versus dalteparin group (3.1%) at 6 months was not statistically significant (p = 0.675). No significant difference was identified between the rivaroxaban group and dalteparin group in the rate of major bleeding (2.8 vs. 1.1%, respectively). Rivaroxaban was comparable to dalteparin in prevention of VTE recurrence while having no significant differences with major or minor bleeding.

How MYC reprograms metabolism in primary tumors remains poorly understood. Using integrated gene expression and metabolite profiling, we identify six pathways that are coordinately deregulated in primary MYC-driven liver tumors: glutathione metabolism; glycine, serine, and threonine metabolism; aminoacyl-tRNA biosynthesis; cysteine and methionine metabolism; ABC transporters; and mineral absorption. We then focus our attention on glutathione (GSH) and glutathione disulfide (GSSG), as they are markedly decreased in MYC-driven tumors. We find that fewer glutamine-derived carbons are incorporated into GSH in tumor tissue relative to non-tumor tissue. Expression of GCLC, the rate-limiting enzyme of GSH synthesis, is attenuated by the MYC-induced microRNA miR-18a. Inhibition of miR-18a in vivo leads to increased GCLC protein expression and GSH abundance in tumor tissue. Finally, MYC-driven liver tumors exhibit increased sensitivity to acute oxidative stress. In summary, MYC-dependent attenuation of GCLC by miR-18a contributes to GSH depletion in vivo, and low GSH corresponds with increased sensitivity to oxidative stress in tumors. Our results identify new metabolic pathways deregulated in primary MYC tumors and implicate a role for MYC in regulating a major antioxidant pathway downstream of glutamine.

Hepatocellular carcinoma (HCC) is associated with poor survival for patients and few effective treatment options, raising the need for novel therapeutic strategies. MicroRNAs (miRNAs) play important roles in tumor development and show deregulated patterns of expression in HCC. Because of the liver’s unique affinity for small nucleic acids, miRNA-based therapy has been proposed in the treatment of liver disease. Thus, there is an urgent need to identify and characterize aberrantly expressed miRNAs in HCC. In our study, we profiled miRNA expression changes in de novo liver tumors driven by MYC and/or RAS, two canonical oncogenes activated in a majority of human HCCs. We identified an up-regulated miRNA megacluster comprised of 53 miRNAs on mouse chromosome 12qF1 (human homolog 14q32). This miRNA megacluster is up-regulated in all three transgenic liver models and in a subset of human HCCs. An unbiased functional analysis of all miRNAs within this cluster was performed. We found that miR-494 is overexpressed in human HCC and aids in transformation by regulating the G1/S cell cycle transition through targeting of the Mutated in Colorectal Cancer tumor suppressor. miR-494 inhibition in human HCC cell lines decreases cellular transformation, and anti-miR-494 treatment of primary MYC-driven liver tumor formation significantly diminishes tumor size. Conclusion: Our findings identify a new therapeutic target (miR-494) for the treatment of HCC. (Hepatology 2014;58:202–215)

The tightly controlled replication of hepatocytes in liver regeneration and uncontrolled proliferation of tumor cells in hepatocellular carcinoma (HCC) are often modulated by common regulatory pathways. Several microRNAs (miRNAs) are involved in HCC progression by modulating posttranscriptional expression of multiple target genes. miR-221, which is frequently up-regulated in HCCs, delays fulminant liver failure in mice by inhibiting apoptosis, indicating a pleiotropic role of miR-221 in hepatocytes. Here, we hypothesize that modulation of miR-221 targets in primary hepatocytes enhances proliferation, providing novel clues for enhanced liver regeneration. We demonstrate that miR-221 enhances proliferation of in vitro cultivated primary hepatocytes. Furthermore, applying two-thirds partial hepatectomy as a surgically induced liver regeneration model we show that adeno-associated virus-mediated overexpression of miR-221 in the mouse liver also accelerates hepatocyte proliferation in vivo. miR-221 overexpression leads to rapid S-phase entry of hepatocytes during liver regeneration. In addition to the known targets p27 and p57, we identify Aryl hydrocarbon nuclear translocator (Arnt) messenger RNA (mRNA) as a novel target of miR-221, which contributes to the pro-proliferative activity of miR-221. Conclusion: miR-221 overexpression accelerates hepatocyte proliferation. Pharmacological intervention targeting miR-221 may thus be therapeutically beneficial in liver failure by preventing apoptosis and by inducing liver regeneration. (HEPATOLOGY 2013;)

The dynamic behavior of porcine brain tissue, obtained from a series of in vitro observations and experiments, is analyzed and described here with the aid of a large strain, nonlinear, viscoelastic constitutive model. Mixed gray and white matter samples excised from the superior cortex were tested in unconfined uniaxial compression within 15h post mortem. The test sequence consisted of three successive load-unload segments at strain rates of 1, 0.1 and 0.01 s⁻¹, followed by stress relaxation (n=25). The volumetric compliance of the tissue was assessed for a subset of specimens (n=7) using video extensometry techniques. The tissue response exhibited moderate compressibility, substantial nonlinearity, hysteresis, conditioning and rate dependence. A large strain kinematics nonlinear viscoelastic model was developed to account for the essential features of the tissue response over the entire deformation history. The corresponding material parameters were obtained by fitting the model to the measured conditioned response (axial and volumetric) via a numerical optimization scheme. The model successfully captures the observed complexities of the material response in loading, unloading and relaxation over the entire range of strain rates. The accuracy of the model was further verified by comparing model predictions with the tissue response in unconfined compression at higher strain rate (10 s⁻¹) and with literature data in uniaxial tension. The proposed constitutive framework was also found to be adequate to model the loading response of brain tissue in uniaxial compression over a wider range of strain rates (0.01-3000 s⁻¹), thereby providing a valuable tool for simulations of dynamic transients (impact, blast/shock wave propagation) leading to traumatic brain injury.

Inactivation of the p53 tumor suppressor pathway allows cell survival in times of stress and occurs in many human cancers; however, normal embryonic stem cells and some cancers such as neuroblastoma maintain wild-type human TP53 and mouse Trp53 (referred to collectively as p53 herein). Here we describe a miRNA, miR-380-5p, that represses p53 expression via a conserved sequence in the p53 3' untranslated region (UTR). miR-380-5p is highly expressed in mouse embryonic stem cells and neuroblastomas, and high expression correlates with poor outcome in neuroblastomas with neuroblastoma derived v-myc myelocytomatosis viral-related oncogene (MYCN) amplification. miR-380 overexpression cooperates with activated HRAS oncoprotein to transform primary cells, block oncogene-induced senescence and form tumors in mice. Conversely, inhibition of endogenous miR-380-5p in embryonic stem or neuroblastoma cells results in induction of p53, and extensive apoptotic cell death. In vivo delivery of a miR-380-5p antagonist decreases tumor size in an orthotopic mouse model of neuroblastoma. We demonstrate a new mechanism of p53 regulation in cancer and stem cells and uncover a potential therapeutic target for neuroblastoma.

High polarization of nuclear spins in liquid state through hyperpolarized technology utilizing dynamic nuclear polarization has enabled the direct monitoring of 13C metabolites in vivo at a high signal-to-noise ratio (SNR) (1,2). Metabolic imaging studies thus far have focused on injecting hyperpolarized [1-13C]pyruvate and observing its uptake and conversion to [1-13C]lactate, [1-13C]alanine, 13C-bicarbonate, and 13CO2 (3–11). These studies have shown the potential of hyperpolarized technology for the metabolic imaging of cardiac disease (4,10,11) and cancer (5,7,8,12). The hyperpolarized cancer studies have demonstrated that in tumors the lactate dehydrogenase–catalyzed reaction involving pyruvate and lactate results in dramatically higher levels of hyperpolarized 13C lactate than in normal tissue (5,7,8,12). Mechanistically, lactate dehydrogenase catalyzes rapid exchange of the 13C label between pyruvate and lactate; thus, detected 13C lactate likely reflects the size of the preexisting endogenous lactate pool and lactate dehydrogenase expression (8). Hyperpolarization of clinically relevant substrates other than [1-13C]pyruvate is also an active area of research. Promising results have been reported for the hyperpolarization of [1-13C]lactate (13), [5-13C]glutamine (14), and 13C bicarbonate (15). Regardless of the specific in vivo application or substrate being hyperpolarized, the overriding limitation in dynamic nuclear polarization hyperpolarized spectroscopic imaging is the rapid decay of the hyperpolarized signal, which decreases exponentially with the spin-lattice T1 of the 13C nucleus (on the order of 30 to 70 sec for most substrates polarized). The hyperpolarized signal is also irretrievably lost due to saturation from radiofrequency excitation. These factors severely limit the number of phase encodes and thus the spatial resolution/coverage achievable, making accelerated imaging methods very important. Our approach in this project was to apply compressed sensing, a recently developed technique based on random undersampling and a nonlinear reconstruction (16– 19). Compressed sensing works well when underlying signals exhibit sparsity and have adequate SNR but may fail if those conditions are not met (20). The key design challenge in implementing compressed sensing for specific MRI applications is the development of pulse sequences and acquisition schemes that incorporate “incoherent” sampling, which is achieved by pseudorandom undersampling (20). In a prior study, an initial design incorporated pseudorandom undersampling in one spatial dimension into a spectroscopic imaging sequence to achieve 2-fold acceleration for 2-fold finer spatial resolution without increasing scan time (21). In this project, we advanced this compressed sensing methodology to two spatial dimensions and developed a 7.53-fold accelerated sequence for three-dimensional (3D) spectroscopic imaging, which was investigated through simulations, phantom testing, and in vivo experiments. In simulations, the limits of undersampling and the influence of noise on the compressed sensing nonlinear reconstruction were explored. We also applied this technique for hyperpolarized 13C imaging research in transgenic mice that express human oncogenes and develop liver cancer, a new animal model in which the higher spatial resolution is particularly beneficial.

Purpose To evaluate use of medical, laser, or incisional surgical interventions for glaucoma after laser peripheral iridotomy (LPI). Design Retrospective longitudinal cohort study. Methods All enrollees aged ≥21 years in a US managed-care network who underwent bilateral LPIs in 2001–2011 were identified. The mean numbers of pre- and post-LPI glaucoma medication classes prescribed and the proportion of enrollees requiring cataract or glaucoma surgery within 2 years after the LPIs were determined. Multivariable logistic regression assessed factors associated with enrollees' prescription of ≥1 glaucoma medication class after bilateral LPIs. Results Of the 1660 patients undergoing bilateral LPIs, 1280 (77.1%) had no pre- or post-LPI prescriptions for any glaucoma medication class. Of the remaining patients, 251 (66.1%) required more glaucoma medication classes after than before the procedures, whereas 44 (11.6%) used fewer after the procedures; 85 (22.4%) were prescribed the same number before and after the LPIs. A total of 167 patients (10.1%) underwent cataract surgery and 79 (4.8%) received glaucoma surgery over the 2-year follow-up. Black patients had a 130% increased odds for glaucoma medication–class prescriptions after bilateral LPIs, compared with white patients ( P = .02). The odds of post-LPI glaucoma medication use increased by 21% for every additional 5 years of age ( P Conclusion Most patients undergoing bilateral LPIs received no pre- or post-LPI glaucoma medication–class prescriptions and had no cataract or additional glaucoma surgery within 2 years after LPIs. Clinicians should alert black or older patients and those already taking glaucoma medications before the procedure of their higher odds of requiring medications afterward.

mir-17-92, a potent polycistronic oncomir, encodes six mature miRNAs with complex modes of interactions. In the Eμ-myc Burkitt’s lymphoma model, mir-17-92 exhibits potent oncogenic activity by repressing c-Myc-induced apoptosis, primarily through its miR-19 components. Surprisingly, mir-17-92 also encodes the miR-92 component that negatively regulates its oncogenic cooperation with c-Myc. This miR-92 effect is, at least in part, mediated by its direct repression of Fbw7, which promotes the proteosomal degradation of c-Myc. Thus, overexpressing miR-92 leads to aberrant c-Myc increase, imposing a strong coupling between excessive proliferation and p53-dependent apoptosis. Interestingly, miR-92 antagonizes the oncogenic miR-19 miRNAs; and such functional interaction coordinates proliferation and apoptosis during c-Myc-induced oncogenesis. This miR-19:miR-92 antagonism is disrupted in B-lymphoma cells that favor a greater increase of miR-19 over miR-92. Altogether, we suggest a new paradigm whereby the unique gene structure of a polycistronic oncomir confers an intricate balance between oncogene and tumor suppressor crosstalk. DOI: http://dx.doi.org/10.7554/eLife.00822.001, eLife digest The role of genes, in very simple terms, is to be transcribed into messenger RNA molecules, which are then translated into strings of amino acids that fold into proteins. Each of these steps is extremely complex, and a wide range of other molecules can speed up, slow down, stop or otherwise disrupt the expression of genes as protein products. Genes can also code for nucleic acids that are not translated into proteins, such as microRNAs. These are small RNA molecules that can reduce the production of proteins by repressing the translation step and/or by partially degrading the messenger RNA molecules. mir-17-92 is a gene that exemplifies much of this complexity. It codes for six different microRNAs in a single primary transcript, and has been implicated in a number of cancers, including lung cancer, Burkitt’s lymphoma and other forms of lymphomas and leukemia. One of six microRNAs has a longer evolutionary history than the remaining five: mir-92 is found in vertebrates, chordates and invertebrates, whereas the other five are only found in vertebrates. However, it is not known how or why the mir-17-92 gene evolved to code for multiple different microRNAs. Olive et al. have studied how these mir-17-92 microRNAs functionally interact in mice with Burkitt’s lymphoma, a form of cancer that is associated with a gene called c-Myc being over-activated. Mutations in this gene promote the proliferation of cells, and in cooperation with other genetic lesions, this ultimately leads to cancer. mir-17-92 is implicated in this cancer because it represses the process of programmed cell death (which is induced by the protein c-Myc) that the body employs to stop tumors growing. Olive et al. found that deleting one of the six microRNAs, miR-92, increased the tendency of the mir-17-92 gene to promote Burkitt’s lymphoma. By repressing an enzyme called Fbw7, miR-92 causes high levels of c-Myc to be produced. While this leads to the uncontrolled proliferation of cells that promotes cancer, it also increases programmed cell death, at least in part, by activating the p53 pathway, a well-known tumor suppression pathway. The experiments also revealed that the action of miR-92 and that of one of the other microRNAs, miR-19, were often opposed to each other. These findings have revealed an unexpected interaction among different components within a single microRNA gene, which acts to maintain an intricate balance between pathways that promote and suppress cancer. DOI: http://dx.doi.org/10.7554/eLife.00822.002

BACKGROUND: Venous thromboembolism is a well-known complication of malignancy. The Khorana Risk Score (KRS) utilizes the type of cancer, blood counts, and body mass index to predict risk of thrombosis in cancer patients. Patients with a KRS of greater than 3 are considered high risk for developing blood clots and may benefit from prophylactic anticoagulation. We wanted to determine if the use of the KRS would have led to prophylactic anticoagulation (AC) in these cancer patients prior to their thrombotic events. METHODS: This study utilized a group of 286 patients treated at Moffitt Cancer Center between May 1, 2010 and June 30, 2015 with a wide variety of cancer diagnoses with known venous thromboembolic events (VTE) (pulmonary embolism or deep venous thrombosis). We aimed to validate the KRS by retrospective analysis to determine if the KRS would have predicted VTE in these patients on the day of their venous thromboembolic event. The demographics are summarized using descriptive statistics. Wilcoxon rank-sum test is used for testing the difference in continuous variables. Fisher exact test is used for testing the difference in categorical variables. RESULTS: We found that the majority of these cancer patients with known VTE (89%) would have been classified as low risk of having VTE. Only 11% would have been classified as high risk to where prophylactic anticoagulation might have been indicated. CONCLUSIONS: We found that in a diverse group of cancer patients who had thrombotic events, the KRS did not appropriately stratify patients at the highest risk of VTE. The majority of patients with VTE were actually found to be low risk which would not have led to improved awareness or medication prophylaxis. Improved risk stratification methods are needed for cancer patients to implement an effective prophylactic strategy. Table Table. Disclosures No relevant conflicts of interest to declare.

Summary Tumor cells have an altered metabolic phenotype characterized by increased glycolysis and diminished oxidative phosphorylation. Despite the suspected importance of glycolysis in tumorigenesis, the temporal relationship between oncogene signaling, in vivo tumor formation, and glycolytic pathway activity is poorly understood. Moreover, how glycolytic pathways are altered as tumors regress remains unknown. Here, we use a switchable model of Myc -driven liver cancer, along with hyperpolarized 13 C-pyruvate magnetic resonance spectroscopic imaging (MRSI) to visualize glycolysis in de novo tumor formation and regression. LDHA abundance and activity in tumors is tightly correlated to in vivo pyruvate conversion to lactate and is rapidly inhibited as tumors begin to regress, as are numerous glycolysis pathway genes. Conversion of pyruvate to alanine predominates in precancerous tissues prior to observable morphologic or histological changes. These results demonstrate that metabolic changes precede tumor formation and regression and are directly linked to the activity of a single oncogene.

Purpose To investigate the effect of a negative pressure fixation device on misregistration artifacts in contrast-enhanced (CE) MR subtraction images. Materials and Methods Nine patients, two of which had been previously diagnosed with breast cancer, were examined with T2-weighted (T2-w) turbo spin-echo (TSE) and three-dimensional (3D) spoiled gradient-recalled echo (SPGR) CE dynamic MRI. Baselines images were subtracted from the dynamic images. A device consisting of two stiff plastic domes was placed on the breasts of each patient. Negative pressure of 27 to 37 mmHg within the domes was maintained. The patient was positioned prone in the coil without the device and imaged as a baseline. Subsequently, the patient was placed into the negative pressure domes and reimaged. One of the nine patients was also imaged supine to establish feasibility for this positioning. Results With the use of the negative pressure fixation device, a reduction in misregistration artifact has been demonstrated in prone imaging. Patients reported improved comfort with the device and feasibility has been shown for supine imaging. Conclusion The device was shown to be MRI-compatible and successfully applied in this pilot study, opening other avenues of exploration. Supine positioning for breast imaging makes possible better access for biopsy and intervention. Further modifications to the device are in order for this purpose and to eliminate motion due to breathing in the prone position. J. Magn. Reson. Imaging 2009;30:430–436. © 2009 Wiley-Liss, Inc.

Plexins are transmembrane high-affinity receptors for semaphorins, regulating cell guidance, motility, and invasion. Functional evidences implicate semaphorin signals in cancer progression and metastasis. Yet, it is largely unknown whether plexin genes are genetically altered in human tumors. We performed a comprehensive gene copy analysis and mutational profiling of all nine members of the plexin gene family (plexinome), in melanomas and pancreatic ductal adenocarcinomas (PDACs), which are characterized by high metastatic potential and poor prognosis. Gene copy analysis detected amplification of PLXNA4 in melanomas, whereas copy number losses of multiple plexin genes were seen in PDACs. Somatic mutations were detected in PLXNA4, PLXNB3, and PLXNC1; providing the first evidence that these plexins are mutated in human cancer. Functional assays in cellular models revealed that some of these missense mutations result in loss of plexin function. For instance, c.1613G>A, p.R538H mutation in the extracellular domain of PLXNB3 prevented binding of the ligand Sema5A. Moreover, although PLXNA4 signaling can inhibit tumor cell migration, the mutated c.5206C>T, p.H1736Y allele had lost this activity. Our study is the first systematic analysis of the "plexinome" in human tumors, and indicates that multiple mutated plexins may be involved in cancer progression

SummaryHepatoblastoma, the most common pediatric liver cancer, is tightly linked to excessive Wnt/β-catenin signaling. Here, we used microarray analysis to identify two tumor subclasses resembling distinct phases of liver development and a discriminating 16-gene signature. β-catenin activated different transcriptional programs in the two tumor types, with distinctive expression of hepatic stem/progenitor markers in immature tumors. This highly proliferating subclass was typified by gains of chromosomes 8q and 2p and upregulated Myc signaling. Myc-induced hepatoblastoma-like tumors in mice strikingly resembled the human immature subtype, and Myc downregulation in hepatoblastoma cells impaired tumorigenesis in vivo. Remarkably, the 16-gene signature discriminated invasive and metastatic hepatoblastomas and predicted prognosis with high accuracy.

A recent systematic sequence analysis of well-annotated human protein coding genes or consensus coding sequences led to the identification of 189 genes displaying somatic mutations in breast and colorectal cancers. Based on their mutation prevalence, a subset of these genes was identified as cancer candidate (CAN) genes as they could be potentially involved in cancer. We evaluated the mutational profiles of 19 CAN genes in the highly aggressive tumors: glioblastoma, melanoma, and pancreatic carcinoma. Among other changes, we found novel somatic mutations in EPHA3, MLL3, TECTA, FBXW7, and OBSCN, affecting amino acids not previously found to be mutated in human cancers. Interestingly, we also found a germline nucleotide variant of OBSCN that was previously reported as a somatic mutation. Our results identify specific genetic lesions in glioblastoma, melanoma, and pancreatic cancers and indicate that CAN genes and their mutational profiles are tumor specific. Some of the mutated genes, such as the tyrosine kinase EPHA3, are clearly amenable to pharmacologic intervention and could represent novel therapeutic targets for these incurable cancers. We also speculate that similar to other oncogenes and tumor suppressor genes, mutations affecting OBSCN could be involved in cancer predisposition. [Cancer Res 2007;67(8):3545–50]

Introduction: Venous thromboembolism (VTE) in the form of deep venous thrombosis (DVT) or pulmonary embolism (PE) is a complication of malignancy. Several studies have demonstrated the superiority of dalteparin (Fragmin®), a low molecular weight heparin (LMWH), in comparison to oral vitamin K antagonists in preventing VTE recurrence in the setting of active cancer. LMWH is the preferred treatment of cancer associated thrombosis. However, the cost of LMWH can be prohibitive and the need for daily subcutaneous injections can decrease patients' quality of life. While rivaroxaban (Xarelto®), a Factor Xa inhibitor, has been approved for the treatment and secondary prevention of DVT and PE, there is limited data regarding its use in cancer patients. The objective of our study is to determine the efficacy and safety of rivaroxaban compared to dalteparin in cancer associated thrombosis. Methods: This is a retrospective chart review of cancer patients greater than age 18 treated at H. Lee Moffitt Cancer Center between May 3, 2010 and June 30, 2015 on anticoagulation with rivaroxaban or dalteparin. Patients were excluded if the length of anticoagulant therapy was < 30 days, anticoagulant therapy was initiated > 6 months after VTE diagnosis, the indication for treatment was not DVT/PE, if patients had contraindications to either LMWH or rivaroxaban, or patients were not on treatment doses of therapy. Out of 459 patients identified, 226 patients (107 in the rivaroxaban group, and 119 in the dalteparin group) were eligible for analysis based on our exclusion criteria. Efficacy was determined by the incidence of recurrent VTE, such as recurrent DVT, new fatal or non-fatal PE within 30 days. The secondary endpoint of the study was to determine the safety of rivaroxaban compared to dalteparin in cancer patients for the treatment of VTE. Safety was determined by the incidence and severity of bleeding. Major bleeding was defined as clinically overt if it was associated with a fall in hemoglobin of 2 g/dL or more, required transfusions of ≥ 2 units of packed red blood cells, involved retroperitoneal, intracranial, or critical site bleeding, or if it contributed to death. Minor bleeding was defined as overt bleeding not meeting the criteria for major bleeding but associated with medical intervention, unscheduled contact with a physician, interruption or discontinuation of anticoagulation treatment, or associated with any other discomfort such as pain or impairment of activities of daily life. Descriptive statistical analyses were utilized. Chi square analysis and t- test were performed to compare categorical and continuous variables. All data was analyzed using SPSS version 21.0 statistical software. Results: Rivaroxaban had a similar rate of DVT and PE failure with 1 event versus 2 with dalteparin (p = 0.625). The rivaroxaban group had 0 major and 8 minor bleeds compared to 3 major and 8 minor bleeds in the dalteparin group with p values of 0.09 and 0.86 respectively. Comorbidities and risk factors for thrombosis were similar in both groups as summarized in Table 1. Table. Rivaroxaban vs. Dalteparin: No Significant Differences in the Efficacy and Safety Profile in Cancer Associated Thrombosis RivaroxabanN = 107 DalteparinN =119 P value DVT Failure within 30 days 1 (0.93%) 2 (1.68%) 0.625 PE Failure within 30 days 1 (0.93%) 1 (0.84%) 0.94 Major Bleeding 0 (0 %) 3 (2.5%) 0.09 Minor Bleeding 8 (7.5%) 8 (6.7%) 0.864 Median Age (Yrs) 61 65 0.93 MaleFemale 58 (54.2%) 49 (45.8%) 60 (50.4%) 59 (49.6%) 0.596 Active Cancer 96 (86.5%) 111 (93.2%) 0.350 Surgery within 30 Days 14 (13.1%) 13 (10.9%) 0.684 Hypertension 58 (54.2%) 61 (51.3%) 0.69 Diabetes 14 (13.1%) 14 (11.8%) 0.84 Coronary Artery Disease 6 (5.61%) 11 (9.2%) 0.326 History of Previous DVT 12 (11.2%) 5 (4.2%) 0.074 BMI >30 39 (36.4%) 48 (40.3%) 0.585 Creatinine Clearance (Cr Cl) 30 - 50 Cr Cl 50 - 70 7 (6.5%) 100 (93.3%) 7 (5.9%) 112 (94.1%) 0.837 Conclusions: Our study evaluated the safety and efficacy of rivaroxaban compared to dalteparin in patients with predominantly active cancer treated at a large comprehensive cancer center and found rivaroxaban to be comparable to dalteparin in this cohort. There were no significant differences in regards to recurrent VTE or major/minor bleeding with patients on rivaroxaban or dalteparin in our cohort of patients. Large randomized trials evaluating the efficacy and safety of rivaroxaban in the oncology population are needed to further validate our findings. Disclosures No relevant conflicts of interest to declare.

Recent research suggests that MYC activation in tumor cells leads to a unique metabolic phenotype that is characterized by glutamine addiction and TCA cycle activation. We wish to identify novel metabolic pathways that are altered in MYC-driven cancer in vivo. To that end, we have performed microarray-based transcriptomics and mass-spectrometry-based metabolomics profiling of tumors from a murine model of MYC-driven liver cancer. Using Fisher's exact test, we have identified glutathione metabolism as the most significantly enriched pathway across the two datasets. Notably, both the reduced and oxidized isoforms of glutathione, a major cellular antioxidant, are depleted in tumors relative to naïve control livers. We find that the rate-limiting enzyme of glutathione synthesis, Gclc, is attenuated by a MYC-regulated microRNA miR-18a. Loss of glutathione production is concomitant with increased glutamine conversion into TCA cycle metabolites in vivo. Despite loss of glutathione and another antioxidant, NADPH, our MYC-driven tumors do not exhibit markers of elevated oxidative stress. Instead, they appear to upregulate a host of alternative antioxidant pathways including Vitamin C and thioredoxins. In summary, while it is well established that MYC-driven tumors have increased dependence on glutamine resulting in increased glutamate production, whether MYC also regulates glutamate utilization decisions remains poorly understood. Here we show that MYC can regulate glutamate flux by attenuating glutathione production, shifting glutamate utilization towards the TCA cycle. Citation Format: Brittany Anderton, Asha Balakrishnan, Sanjeev Balakrishnan, Lionel Lim, Rebecca Kohnz, Dan Nomura, Andrei Goga. MYC regulates glutathione depletion and glutamine utilization via miR-18a in vivo. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A01.

micro-RNA-21 is frequently over-expressed and has been shown to correlate with poor outcome in multiple cancer types. Its genomic locus is amplified in some cancer types and miR-21 is also transactivated by several known cancer drivers (e.g. STAT3 and Ras). We have used a publically available data set from 86 patients to show that miR-21 is over-expressed in hepatocellular carcinoma (HCC). The treatment options for HCC are limited, thus making it the third leading cause of cancer related deaths worldwide. Additional treatments for HCC are greatly needed. We investigated the therapeutic potential of inhibiting miR-21 with chemically modified oligonucleotides known as anti-miRs using models of HCC, including a genetically engineered mouse model of HCC driven by an inducible, activated form of Ras. Short term treatment with the anti-miR led to a reduction in tumor formation. Furthermore, inhibition of miR-21 was clearly demonstrated by analysis of genome wide mRNA expression data from treated versus untreated tumors. This data showed that genes containing the mir-21 octamer sequence were the most significantly over-enriched among up-regulated genes compared to all of the other 65,535 possible octamers. We also determined the effect of long-term anti-miR-21 treatment on the survival in this mouse model of HCC. anti-miR-21 treated mice demonstrated a highly significant survival advantage (p Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4708. doi:10.1158/1538-7445.AM2011-4708

Combinations of genetic alterations in cancer genes lead to aberrant signaling properties and drive cellular transformation. Whether each oncogene gives rise to unique signals or combinations of oncogenes lead to new properties of cancer cells remains unclear. Using cell-based and animal model systems it has been shown that certain oncogenes can cooperate with each other to induce a fully malignant tumor phenotype. In addition, the combination of oncogenes and the extent of cooperation between them to give rise to a tumor may vary in different cancers. Cooperativity between MYC and RAS oncogenes has been observed in different cancer types. MYC is often overexpressed and sometimes amplified in cancer, while, activating RAS mutations occur in about 30% human cancers. Hepatocellular carcinoma (HCC) is among the four leading causes of cancer-related death. Currently, except for early surgical intervention or liver transplantation, no effective cures exist. Overexpression of both MYC and activated HRAS together in primary human liver tumors has been associated with aggressive forms of liver cancer with an especially poor prognosis. However, a systematic approach to understanding MYC and RAS cooperation in liver cancer has not yet been undertaken. We have discovered that transgenic mice overexpressing MYC, RAS or both MYC and RAS in their liver, give rise to distinct liver tumors. MYC and RAS coexpression led to faster tumor development and decreased survival. To gain a comprehensive view of the molecular changes that contribute to MYC and RAS oncogene cooperation in de novo liver tumors, we combined the conditional transgenic models of liver cancer with global gene expression, signaling pathway analyses and functional studies. Comparisons were made to clinically annotated human tumors and key pathways validated in cell lines and animal models. We show that tumors driven by either oncogene or a combination of both are phenotypically and molecularly distinct from each other with differential regulation of multiple genes and pathways. Our work suggests that MYC and RAS cooperate through specific genes, such as CCNE1 and multiple signaling pathways including proliferation, apoptosis, angiogenesis and multiple metabolic pathways, to contribute to liver cancer development. We also show molecular alterations across signaling pathways are comparable between mouse and human liver cancers. Primary human liver tumors can be segregated into distinct subsets based on differentially regulated gene sets from cooperating MYC and RAS tumors. These results indicate that molecular changes underlying MYC and RAS cooperation may serve as ideal molecular markers and therapeutic targets for liver cancer. Citation Information: Clin Cancer Res 2010;16(14 Suppl):B54.

Background Temozolomide is an alkylating agent used along with concurrent radiation therapy in the treatment of glioblastoma. The primary adverse effect of temozolomide is bone marrow suppression with resulting cytopenias. There have been reported cases of temozolomide-induced hepatotoxicity, including fatal liver failure, associated with reactivation of the hepatitis virus or with concurrent use of other hepatotoxic drugs. In this report, we describe a unique mechanism of temozolomide-induced liver injury with supporting histopathology. Case presentation Our patient, a 58-year-old African american woman with glioblastoma, was treated with concurrent radiation and temozolomide therapy. After 6 weeks of treatment, she developed worsening transaminitis and bilirubinemia with liver biopsy results consistent with drug-induced cholestasis and ductopenia. After cessation of drug treatment, her hyperbilirubinemia progressed with a peak bilirubin of 36.8 mg/dl. A repeat liver biopsy revealed severe biliary ductopenia consistent with vanishing bile duct syndrome. Conclusions We present a rare case of a patient with biliary ductopenia as an adverse effect of temozolomide. During radiation and temozolomide therapy, blood counts and liver enzymes should be carefully monitored for the development of cholestatic liver injury. We recommend monitoring with weekly liver function tests and minimizing drugs that are metabolized by the liver during chemoradiation for glioblastoma.