Sonya Zabludoff

miR-21 inhibition reduces liver fibrosis and prevents tumor development by inducing apoptosis of CD24+ progenitor cells

miR-21 is upregulated in hepatocellular carcinoma and intrahepatic cholangiocarcinoma, where it is associated with poor prognosis. Here, we offer preclinical evidence that miR-21 offers a therapeutic and chemopreventive target in these liver cancers. In mice with hepatic deletion of Pten, anti-miR-21 treatment reduced liver tumor growth and prevented tumor development. These effects were accompanied with a decrease in liver fibrosis and a concomitant reduction of CD24(+) liver progenitor cells and S100A4(+) cancer-associated stromal cells. Notch2 inhibition also occurred in tumors following anti-miR-21 treatment. We further showed that miR-21 is necessary for the survival of CD24(+) progenitor cells, a cellular phenotype mediated by Notch2, osteopontin, and integrin αv. Our results identify miR-21 as a key regulator of tumor-initiating cell survival, malignant development, and growth in liver cancer, highlighting the role of CD24(+) cells in the expansion of S100A4(+) cancer-associated stromal cells and associated liver fibrosis.

Anti–miR-21 Suppresses Hepatocellular Carcinoma Growth via Broad Transcriptional Network Deregulation

Hepatocellular carcinoma (HCC) remains a significant clinical challenge with few therapeutic options available to cancer patients. MicroRNA 21-5p (miR-21) has been shown to be upregulated in HCC, but the contribution of this oncomiR to the maintenance of tumorigenic phenotype in liver cancer remains poorly understood. We have developed potent and specific single-stranded oligonucleotide inhibitors of miR-21 (anti-miRNAs) and used them to interrogate dependency on miR-21 in a panel of liver cancer cell lines. Treatment with anti–miR-21, but not with a mismatch control anti-miRNA, resulted in significant derepression of direct targets of miR-21 and led to loss of viability in the majority of HCC cell lines tested. Robust induction of caspase activity, apoptosis, and necrosis was noted in anti–miR-21-treated HCC cells. Furthermore, ablation of miR-21 activity resulted in inhibition of HCC cell migration and suppression of clonogenic growth. To better understand the consequences of miR-21 suppression, global gene expression profiling was performed on anti–miR-21-treated liver cancer cells, which revealed striking enrichment in miR-21 target genes and deregulation of multiple growth-promoting pathways. Finally, in vivo dependency on miR-21 was observed in two separate HCC tumor xenograft models. In summary, these data establish a clear role for miR-21 in the maintenance of tumorigenic phenotype in HCC in vitro and in vivo. Implications: miR-21 is important for the maintenance of the tumorigenic phenotype of HCC and represents a target for pharmacologic intervention. Mol Cancer Res; 13(6); 1009–21. ©2015 AACR.

Identification of the endosomal sorting complex required for transport-I (ESCRT-I) as an important modulator of anti-miR uptake by cancer cells

Mechanisms of unassisted delivery of RNA therapeutics, including inhibitors of microRNAs, remain poorly understood. We observed that the hepatocellular carcinoma cell line SKHEP1 retains productive free uptake of a miR-21 inhibitor (anti-miR-21). Uptake of anti-miR-21, but not a mismatch (MM) control, induces expression of known miR-21 targets (DDAH1, ANKRD46) and leads to dose-dependent inhibition of cell growth. To elucidate mechanisms of SKHEP1 sensitivity to anti-miR-21, we conducted an unbiased shRNA screen that revealed tumor susceptibility gene 101 (TSG101), a component of the endosomal sorting complex required for transport (ESCRT-I), as an important determinant of anti-proliferative effects of anti-miR-21. RNA interference-mediated knockdown of TSG101 and another ESCRT-I protein, VPS28, improved uptake of anti-miR-21 in parental SKHEP1 cells and restored productive uptake to SKHEP1 clones with acquired resistance to anti-miR-21. Depletion of ESCRT-I in several additional cancer cell lines with inherently poor uptake resulted in improved activity of anti-miR-21. Finally, knockdown of TSG101 increased uptake of anti-miR-21 by cancer cells in vivo following systemic delivery. Collectively, these data support an important role for the ESCRT-I complex in the regulation of productive free uptake of anti-miRs and reveal potential avenues for improving oligonucleotide free uptake by cancer cells.

Shift of microRNA profile upon glioma cell migration using patient-derived spheroids and serum-free conditions

Glioblastoma multiforme (GBM) is the most frequent malignant primary brain tumor. A major reason for the overall median survival being only 14.6 months is migrating tumor cells left behind after surgery. Another major reason is tumor cells having a so-called cancer stem cell phenotype being therefore resistant towards traditional chemo- and radiotherapy. A group of novel molecular targets are microRNAs (miRNAs). MiRNAs are small non-coding RNAs exerting post-transcriptional regulation of gene expression. The aim of this study was to identify differentially expressed miRNAs in migrating GBM cells using serum-free stem cell conditions. We used patient-derived GBM spheroid cultures for a novel serum-free migration assay. MiRNA expression of migrating tumor cells isolated at maximum migration speed was compared with corresponding spheroids using an OpenArray Real-Time PCR System. The miRNA profiling revealed 30 miRNAs to be differentially expressed. In total 13 miRNAs were upregulated and 17 downregulated in migrating cells compared to corresponding spheroids. The three most deregulated miRNAs, miR-1227 (up-regulated), miR-32 (down-regulated) and miR-222 (down-regulated), were experimentally overexpressed. A non-significantly increased migration rate was observed after miR-1227 overexpression. A significantly reduced migration rate was observed after miR-32 and miR-222 overexpression. In conclusion a shift in microRNA profile upon glioma cell migration was identified using an assay avoiding serum-induced migration. Both the miRNA profiling and the functional validation suggested that miR-1227 may be associated with increased migration and miR-32 and miR-222 with decreased migration. These miRNAs may represent potential novel targets in migrating glioma cells.

Abstract 1459: miR-221: A potential therapeutic target for hepatocellular carcinoma

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA microRNAs, which control post-transcriptional gene expression by repressing mRNA translation and/or causing mRNA degradation, play important roles in human cancers. miR-221 is one of the two microRNAs in the miR-221/222 cluster located in chromosome-X, targets key cancer pathways and inhibit translation of several tumor suppressors including p27, p57, and PTEN. miR-221 is up-regulated by >2-fold in 55% and >5-fold in 14% of human hepatocellular carcinoma (HCC) tumor samples. Importantly, it has been shown in preclinical HCC models that miR-221 overexpression accelerated tumorigenesis, while miR-221 inhibition reduced tumor growth. To identify novel microRNA antagonists that specifically inhibit miR-221 (refer to as miR-221 anti-miRs) for the treatment of HCC, we have generated a number of chemically-modified oligonucleotides and screened for their ability to inhibit miR-221 functions. A number of potent and metabolically stable miR-221 anti-miRs devoid of proinflammatory potential were identified. These miR-221 anti-miRs were tested in a number of human HCC cell lines that highly express miR-221 compare to normal adult human hepatocytes. We demonstrated the de-repression of both p27 mRNA and p27 protein in HCC cells following treatment with miR-221 anti-miRs. We also showed in HCC cells the de-repression of a novel miR-221 target gene recently identified through an argonuate pull-down assay (Ago-IP), alongside with the enrichment of global miR-221 target seeds (as defined by TargetScan) following miR-221 anti-miRs treatment. We then sought to determine the biologic consequences following miR-221 inhibition in HCC cells. In standard cell proliferation assays, we demonstrated that HCC cells responded to miR-221 anti-miRs treatment with IC50s of 125 to 500nM under free-uptake conditions and IC50s of 5 to 75 nM under transfection conditions. In addition, we also showed that miR-221 anti-miRs treatment disrupted HCC cell cycle transition. Altogether, our data showed that miR-221 inhibition de-repressed p27, blocked cell cycle progression and reduced cell proliferation in HCC cells, and supports the notion of miR-221 as a potential therapeutic target for the treatment of HCC. Further preclinical testing of our miR-221 anti-miRs is currently in progress. Citation Format: Edmund C. Lee, Jessica Xu, Thomas Vincent, Jie Chen, Michael Nelson, Xinqiang Huang, Eric Marcusson, John Androsavich, Scott Davis, Adam Pavlicek, Neil Gibson, Sonya Zabludoff. miR-221: A potential therapeutic target for hepatocellular carcinoma. [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 1459. doi:10.1158/1538-7445.AM2014-1459

Anti-miR-17 therapy delays tumorigenesis in MYC-driven hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) remains a significant clinical challenge with few therapeutic options. Genomic amplification and/or overexpression of the MYC oncogene is a common molecular event in HCC, thus making it an attractive target for drug therapy. Unfortunately, currently there are no direct drug therapies against MYC. As an alternative strategy, microRNAs regulated by MYC may be downstream targets for therapeutic blockade. MiR-17 family is a microRNA family transcriptionally regulated by MYC and it is commonly overexpressed in human HCCs. In this study, we performed systemic delivery of a novel lipid nanoparticle (LNP) encapsulating an anti-miR-17 oligonucleotide in a conditional transgenic mouse model of MYC driven HCC. Treatment with anti-miR-17 in vivo, but not with a control anti-miRNA, resulted in significant de-repression of direct targets of miR-17, robust apoptosis, decreased proliferation and led to delayed tumorigenesis in MYC-driven HCCs. Global gene expression profiling revealed engagement of miR-17 target genes and inhibition of key transcriptional programs of MYC, including cell cycle progression and proliferation. Hence, anti-miR-17 is an effective therapy for MYC-driven HCC.

Lipid Nanoparticle–Mediated Delivery of Anti-miR-17 Family Oligonucleotide Suppresses Hepatocellular Carcinoma Growth

Hepatocellular carcinoma (HCC) is one of the most common human malignancies with poor prognosis and urgent unmet medical need. Aberrant expression of multiple members of the miR-17 family are frequently observed in HCC, and their overexpression promotes tumorigenic properties of HCC cells. However, whether pharmacologic inhibition of the miR-17 family inhibits HCC growth remains unknown. In this study, we validated that the miR-17 family was upregulated in a subset of HCC tumors and cell lines and its inhibition by a tough decoy inhibitor suppressed the growth of Hep3B and HepG2 cells, which overexpress the miR-17 family. Furthermore, inhibition of the miR-17 family led to a global derepression of direct targets of the family in all three HCC cell lines tested. Pathway analysis of the deregulated genes indicated that the genes associated with TGFβ signaling pathway were highly enriched in Hep3B and HepG2 cells. A miR-17 family target gene signature was established and used to identify RL01-17(5), a lipid nanoparticle encapsulating a potent anti-miR-17 family oligonucleotide. To address whether pharmacologic modulation of the miR-17 family can inhibit HCC growth, RL01-17(5) was systemically administrated to orthotopic Hep3B xenografts. Suppression of Hep3B tumor growth in vivo was observed and tumor growth inhibition correlated with induction of miR-17 family target genes. Together, this study provides proof-of-concept for targeting the miR-17 family in HCC therapy. Mol Cancer Ther; 16(5); 905–13. ©2017 AACR.

Abstract 1461: A miR-221 multigene pharmacodynamic signature for assessing miR-221 inhibition

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA miR-221 targets key cancer pathways, inhibits translation of important tumor suppressors, and is overexpressed in hepatocellular carcinoma (HCC). Aberrant miR-221 expression has been linked to HCC progression, while inhibition of miR-221 has been shown to reduce tumor growth. In preclinical models, miR-221 inhibition can be assessed by measuring de-repression of known miR-221 target genes such as p27. However, changes in individual microRNA target genes are often small and model-dependent; and comprehensive assessment of pharmacodynamic (PD) effects following microRNA inhibition is often challenging. Herein, we present a miR-221 multigene PD signature that can assess miR-221 target engagement with a large dynamic window and work across different human HCC models following miR-221 inhibition. In the first stage, we transfected five different human HCC lines with two chemically-modified oligonucleotides that inhibit miR-221 functions (miR-221 anti-miRs) and a microRNA-duplex that mimics miR-221/222 functions (mimic). The resulting global mRNA expression changes were compared to mock treated cells using GeneChip Human Genome U133 Plus 2.0 Array (Affymetrix). Ninety unique human genes with transcripts containing conserved and/or 8-mer target seeds (TargetScan), that significantly went up and down after anti-miR-221s and mimic treatment respectively, were further profiled with qPCR in the second stage. Out of the 90 tested transcripts, 62 of them were significantly up-regulated by anti-miR-221s but not by control oligonucleotides (either mismatch or targeting unrelated microRNAs). From the 62 genes, an optimal multigene signature consisted of 13 unique human genes normalized by 6 reference housekeeping genes was identified. We also devised a “miR-221 signature score” and demonstrated that our multigene signature can separate miR-221 anti-miRs treatment from control oligonucleotides with a high degree of sensitivity and specificity. We further validated this multigene signature by demonstrating that it correctly distinguished miR-221 anti-miRs treatment from controls in three additional HCC cell lines in vitro and one HCC model in vivo. In summary, our miR-221 multigene PD signature analysis provided a comprehensive assessment of miR-221 inhibition, with significantly larger dynamic window compare to individual gene analysis, that may be used to discover, rank order and guide the development of novel miR-221 anti-miRs for the treatment of human cancers. Citation Format: Adam Pavlicek, Thomas Vincent, Oivin Guicherit, Nelson Chau, Sonya Zabludoff, Neil Gibson, Edmund C. Lee. A miR-221 multigene pharmacodynamic signature for assessing miR-221 inhibition. [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 1461. doi:10.1158/1538-7445.AM2014-1461

Abstract 5234: Serum microRNAs reflect microRNA expression in tumor tissues as well as systemic response to disease in HRAS-driven mouse models of HCC

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Circulating microRNAs are promising candidates as minimally-invasive biomarkers for tumor detection, disease monitoring, and patient stratification. Increases in serum concentrations have been reported for many microRNAs up-regulated in tumor cells. However, how well global changes in tumor microRNA expression are reflected in circulating microRNAs is less understood. To answer this question, we performed experiments in a Tet-regulated mouse HRAS model of hepatocellular carcinoma (HCC). Male mice develop detectable HCC within a few weeks from activation of the oncogenic HRAS allele. Matched serum and liver tissues for microRNA profiling were collected at three timepoints: right before HRAS activation (normal liver), 3 weeks after activation (moderate tumor burden), and 6 weeks after activation (pervasive tumors). To emulate the effect of targeted treatment, we inactivated the HRAS allele in a group of animals 3 weeks after activation and collected serum and liver tissues at the 6 weeks timepoint (3 weeks HRAS on, 3 weeks off). Global liver and serum microRNA profiles were measured using the OpenArray TaqMan qPCR Platform. The global microRNA profiling analysis revealed that the overall number of detected serum microRNAs as well as the overall serum expression increased with tumor progression and normalized after the HRAS withdrawal. In the liver, 3 weeks after the HRAS activation we observed small changes with just 7 differentially expressed microRNAs at FDR < 20%. The changes became much more pronounced at 6 weeks with 89 microRNAs passing the FDR < 20% threshold. Most of these changes reversed in the 3 weeks on/3 weeks off group and these samples resembled the normal liver controls. Many microRNAs differentially expressed in the liver were also altered in serum, albeit with smaller average fold changes in serum compared to liver. The fold changes were positively correlated between liver and serum samples (Pearson R = 0.25, p < 0.01). We detected additional significant changes in serum microRNAs not reflected in liver tissues samples. The serum-specific alteration included microRNAs linked to immune response, liver injury and other systemic responses to the tumor burden. Similarly to liver, the serum changes were most pronounced in the 6 weeks HRAS group and partially reverted to normal-like profiles in the 3 weeks on/3 weeks off group. In conclusion, using a mouse model of HCC we found that (1) deregulation of liver microRNA profiles increases with the tumor size and (2) that serum microRNA profiles reflect both changes in the tumor tissues and well systemic response to tumor burden. Importantly, most of the changes in both liver and serum are reversed upon inhibition of the driving oncogene. Thus circulating microRNAs are promising candidates for tumor detection, disease monitoring, and monitoring of treatment response. Citation Format: Adam Pavlicek, Vladyslava Ratushna, Shirley Phillips, Cynthia Heinlein, Jian Li, Vivek Kaimal, Sonya Zabludoff, Nelson Chau. Serum microRNAs reflect microRNA expression in tumor tissues as well as systemic response to disease in HRAS-driven mouse models of HCC. [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 5234. doi:10.1158/1538-7445.AM2014-5234

Abstract 4787: Targeting miR-21 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains a significant unmet medical need with few therapeutic options available. Micro RNA 21 (miR-21) has been shown to be upregulated in HCC, however, contribution of this onco-miR to the maintenance of tumorigenic phenotype in liver cancer remains poorly understood. We have developed potent and specific single-stranded oligonucleotide inhibitors of miR-21 (anti-miR-21) and used them to interrogate dependency on miR-21 in a panel of 20 commercially available HCC cell lines in vitro. Upon lipid-mediated transfection, anti-miR-21, but not its mismatched (MM) control, caused significant de-repression of known direct targets of miR-21 (ANKRD46, DDAH1, RECK1) and inhibited survival of a large subset of HCC cell lines. Treatment of these sensitive HCC cell lines with anti-miR-21 resulted in dose- and time-dependent induction of caspase 3/7 activity. In contrast, non-responder HCC cell lines failed to significantly upregulate caspase activity and maintained viability in the presence of anti-miR compound. Further analysis of responder cell lines revealed robust induction of cell death, inhibition of cell migration and suppression of clonogenic growth upon treatment with miR-21 inhibitor. To better understand the consequences of miR-21 suppression in HCC, we carried out global gene expression profiling of anti-miR-21 treated sensitive liver cancer cells. Striking enrichment in miR-21 targets was noted among upregulated transcripts. Gene ontology analysis identified key cellular processes affected by miR-21 inhibition, including deregulation of metabolic pathways. In addition to the induction of direct miR-21 targets, cyclin H was found to be significantly downregulated upon miR-21 inhibition in the majority of responder cell lines. We hypothesize that inhibition of cyclin H expression, while an indirect effect of miR-21 suppression, could contribute to the activity of anti-miR-21 compounds. In summary, our data suggest that inhibition of miR-21 merits further investigation in the treatment of hepatocellular carcinoma. Citation Format: Sonya Zabludoff, Timothy Wagenaar, Francisco Adrian, Charles Allerson, Heike Arlt, Raffaele Baffa, Bal Bhat, Hui Cao, Scott Davis, Carlos Garcia-Echeverria, Kathrin Heermeier, Shih-Min Huang, Lan Jiang, Eric Marcusson, Christiane Metz-Weidmann, Adam Pavlicek, Jack Pollard, Jennifer Rocnik, Sabine Scheidler, Chaomei Shi, Fangxian Sun, Tatiana Tolstykh, Qunyan Yu, Gang Zheng, Dmitri Wiederschain. Targeting miR-21 in hepatocellular carcinoma. [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 4787. doi:10.1158/1538-7445.AM2014-4787