Jiang, Jinmai

Abstract Previous work by us and others reported decreased expression of miR-199a-3p in hepatocellular carcinoma (HCC) tissues compared to adjacent benign tissue. We report here a significant reduction of miR-199a-3p expression in 7 HCC cell lines (Huh7, HepG2, SNU182, PLC/PRF/5, Hep3B, SNU423 and SNU449) compared to primary hepatocytes. To determine if miR-199a-3p has a tumor suppressive role, miR-199a-3p mimetic was transfected into the 7 HCC cell lines. miR-199a-3p mimetic reduced cell proliferation by approximately 60% compared to control oligonucleotide in only two cell lines (SNU449 and SNU423); the proliferation of the other 5 treated cell lines was similar to control oligonucleotide. A miR-199a-3p mimetic formulated with chemical modifications to enhance stability while preserving processing reduced cell proliferation in SNU449 and SNU423 to the same extent as the commercially available miR-199a-3p mimetic. Furthermore, only the duplex miR-199a-3p mimetic, and not the guide strand alone, was effective at reducing cell viability. Since a CD44 variant was essential for c-Met signaling (Orian-Rousseau, et al., Genes Dev. 2002) and c-Met is a known miR-199a-3p target, we hypothesized that miR-199a-3p may also target CD44. Indeed, miRNA target algorithms predict miR-199a-3p to be a putative target of CD44. Immunoblotting confirmed that only the HCC lines that were sensitive to the effects of miR-199a-3p mimetic (SNU449 and SNU423) were CD44+. Direct targeting of CD44 by miR-199a-3p was confirmed using luciferase reporter assays and immunoblotting. Transfection of miR-199a-3p into SNU449 cells reduced in vitro invasion and sensitized the cells to doxorubicin; both effects were enhanced when hyaluronic acid was added to the cell cultures. An inverse correlation between the expression of miR-199a-3p and CD44 protein was noted in primary HCC tissue specimens. The anti-proliferative and anti-invasive properties of miR-199a-3p mimetic on CD44+ HCC may be a useful targeted therapy for CD44+ HCC. 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 1183. doi:10.1158/1538-7445.AM2011-1183

Abstract Patients with advanced hepatocellular carcinoma (HCC) face a dismal prognosis because of a lack of any effective therapies. To address this situation, we conducted a preclinical investigation of the therapeutic efficacy of oligonucleotides directed against the oncogenic microRNA miR-221, which has been implicated in HCC. Of 9 chemistries evaluated, we determined that a 2′-O-methyl phosphorothioate-modified anti-miR-221 oligonucleotide was most effective at reducing proliferation in vitro. A cholesterol-modified isoform of anti-miR-221 (chol-anti-miR-221) exhibited improved pharmacokinetics and liver tissue distribution compared with unmodified oligonucleotide. Chol-anti-miR-221 significantly reduced miR-221 levels in liver within a week of intravenous administration and in situ hybridization studies confirmed accumulation of the oligonucleotide in tumor cells in vivo. Within the same period, chol-anti-miR-221 reduced tumor cell proliferation and increased markers of apoptosis and cell-cycle arrest, elevating the tumor doubling time and increasing mouse survival. Taken together, our findings offer a preclinical proof of efficacy for chol-anti-miR-221 in a valid orthotopic mouse model of HCC, suggesting that this targeted agent could benefit treatment for patients with advanced HCC. Cancer Res; 71(24); 7608–16. ©2011 AACR.

Abstract Purpose: MicroRNA (miRNA) is a new class of small, noncoding RNA. The purpose of this study was to determine if miRNAs are differentially expressed in hepatocellular carcinoma (HCC). Experimental Design: More than 200 precursor and mature miRNAs were profiled by real-time PCR in 43 and 28 pairs of HCC and adjacent benign liver, respectively, and in normal liver specimens. Results: Several miRNAs including miR-199a, miR-21, and miR-301 were differentially expressed in the tumor compared with adjacent benign liver. A large number of mature and precursor miRNAs were up-regulated in the adjacent benign liver specimens that were both cirrhotic and hepatitis-positive compared with the uninfected, noncirrhotic specimens (P < 0.01). Interestingly, all of the miRNAs in this comparison had increased expression and none were decreased. The expression of 95 randomly selected mRNAs was not significantly altered in the cirrhotic and hepatitis-positive specimens, suggesting a preferential increase in the transcription of miRNA. Comparing the miRNA expression in the HCC tumors with patient's survival time revealed two groups of patients; those with predominantly lower miRNA expression and poor survival and those with predominantly higher miRNA expression and good survival (P < 0.05). A set of 19 miRNAs significantly correlated with disease outcome. A number of biological processes including cell division, mitosis, and G1-S transition were predicted to be targets of the 19 miRNAs in this group. Conclusion: We show that a global increase in the transcription of miRNA genes occurs in cirrhotic and hepatitis-positive livers and that miRNA expression may prognosticate disease outcome in HCC.