Suppression of tumor growth using antisense oligonucleotide against survivin in an orthotopic transplant model of human hepatocellular carcinoma in nude mice

Inhibition of survivin by 2'-O-methyl phosphorothioate-modified steric-blocking antisense oligonucleotides

Chemically modified antisense oligonucleotide (ASO) has been established as a successful therapeutic strategy for treating various human diseases. To date, ten ASO drugs, which are capable of either inducing mRNA degradation via RNase H recruitment (fomivirsen, mipomersen, inotersen, volanesorsen and tofersen) or splice modulation (eteplirsen, nusinersen, golodirsen, viltolarsen and casimersen), have been approved by the regulatory agencies for market entry. Nonetheless, none of these approved drugs are prescribed as cancer therapy. Towards this, we have developed steric-blocking ASOs targeting BIRC5 - a well-validated oncogene. Initial screening was performed by transfection of HepG2 cells with seven BIRC5 exon-2 targeting, uniformly 2'-OMe-PS modified ASOs at 400 nM respectively, leading to the identification of two best-performing candidates ASO-2 and ASO-7 in reducing the production of BIRC5 mRNA. Subsequent dose-response assay was conducted via transfection of HepG2 cells by different concentrations (400, 200, 100, 50, 25 nM) of ASO-2 and ASO-7 respectively, showing that both ASOs consistently and efficiently inhibited BIRC5 mRNA expression in a dose-dependent manner. Furthermore, western blot analysis confirmed that ASO-7 could significantly repress survivin production on protein level. Based on our preliminary results, we believe that ASO-7 could be a useful BIRC5 inhibitor for both research purpose and therapeutic development.

Survivin-Based Treatment Strategies for Squamous Cell Carcinoma

Survivin, an anti-apoptotic molecule abundantly expressed in most human neoplasms, has been reported to contribute to cancer initiation and drug resistance in a wide variety of human tumors. Efficient downregulation of survivin can sensitize tumor cells to various therapeutic interventions, generating considerable efforts in its validation as a new target in cancer therapy. This review thoroughly analyzes up-to-date information on the potential of survivin as a therapeutic target for new anticancer treatments. The literature dealing with the therapeutic targeting of survivin will be reviewed, discussing specifically squamous cell carcinomas (SCCs), and with emphasis on the last clinical trials. This review gives insight into the recent developments undertaken in validating various treatment strategies that target survivin in SCCs and analyze the translational possibility, identifying those strategies that seem to be the closest to being incorporated into clinical practice. The most recent developments, such as dominant-negative survivin mutants, RNA interference, anti-sense oligonucleotides, small-molecule inhibitors, and peptide-based immunotherapy, seem to be helpful for effectively downregulating survivin expression and reducing tumor growth potential, increasing the apoptotic rate, and sensitizing tumor cells to chemo- and radiotherapy. However, selective and efficient targeting of survivin in clinical trials still poses a major challenge.

Survivin downregulation using siRNA nanoliposomes inhibits cell proliferation and promotes the apoptosis of MHCC-97H hepatic cancer cells: An in vitro and in vivo study

At present, survivin is one of the most cancer-specific proteins that has been identified. The present study aimed to investigate the antitumor effects of novel survivin small interfering RNA (siRNA) nanoliposomes targeting survivin in human hepatocellular carcinoma MHCC-97H cells and xenograft mouse models. Survivin-targeted siRNA nanoliposomes were prepared and transfected into MHCC-97H cells and MHCC-97H-bearing nude mice. Survivin expression was analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Cell viability was analyzed using an MTT assay and apoptosis was evaluated using Hoechst and Annexin V-fluorescein isothiocyanate/propidium iodide staining. Tumor growth in MHCC-97H-bearing mice was monitored following treatment and tumor samples were obtained for survivin expression analysis using RT-qPCR, western blotting and immunohistochemistry staining. Survivin expression levels were significantly downregulated by nanoliposome-mediated survivin siRNA delivery and this was associated with a significant inhibition of cell growth and an increase in the apoptosis of MHCC-97H cells. Downregulation of survivin expression using survivin siRNA nanoliposomes inhibited tumor growth in the MHCC-97H xenograft models without significant treatment-associated toxicity. Therefore, a cationic nanoliposome-based survivin siRNA delivery system was constructed and demonstrated to be efficient for survivin siRNA delivery in in vitro and in vivo studies. These results demonstrate that survivin downregulation was able to significantly attenuate cell proliferation and induce the apoptosis of MHCC-97H cells, as well as inhibit tumor cell growth in MHCC-97H xenograft models, indicating that survivin suppression using siRNA may contribute to the inhibition of tumor development by suppressing cell proliferation and promoting apoptosis.

Survivin-mediated therapeutic efficacy of gemcitabine through glucose-regulated protein 78 in hepatocellular carcinoma

BACKGROUND

Survivin is an antiapoptotic molecule that is widely expressed in cancers, including hepatocellular carcinoma (HCC). Survivin has become a general therapeutic target for cancers because of its selective overexpression in a majority of tumors. However, little is known regarding the effect of survivin expression in combination with gemcitabine on HCC.

METHODS

We generated survivin knockdown cells (survivin-KD) via a short interfering RNA (siRNA) technique. The antiproliferation effects of gemcitabine were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) assay, and cell cycle evaluation.

RESULTS

According to the MTT assay, we found that survivin-KD cells were more sensitive than parental cells and scrambled control cells to gemcitabine treatment. The apoptotic cell population increased in survivin-KD cells that were treated with gemcitabine in comparison to scrambled control cells, as observed by the cell cycle distribution and TUNEL assays. We found that survivin knockdown resulted in a reduction of glucose-regulated protein 78 (GRP78), which may be responsible for the observed increased survivin-KD cell sensitivity to gemcitabine.

CONCLUSIONS

We conclude that survivin knockdown may contribute to a therapeutic effect of gemcitabine through GRP78 on HCC cells.

Hepatocellular carcinoma: insight from animal models

Hepatocellular carcinoma (HCC) ranks as the third most common cause of death from cancer worldwide. Although major risk factors for the development of HCC have been defined, many aspects of the evolution of hepatocellular carcinogenesis and metastasis are still unknown. Suitable animal models are, therefore, essential to promote our understanding of the molecular, cellular and pathophysiological mechanisms of HCC and for the development of new therapeutic strategies. This Review provides an overview of animal models that are relevant to HCC development, metastasis and treatment. For HCC development, this Review focuses on transgenic mouse models of HBV and HCV infection, which provide experimental evidence that viral genes could initiate or promote liver carcinogenesis. Animal models of HCC metastasis provide platforms to elucidate the mechanisms of HCC metastasis, to study the interaction between the microenvironment and HCC invasion and to conduct intervention studies. In addition, animal models have been developed to investigate the effects of new treatment modalities. The criteria for establishing ideal HCC animal models are also discussed.

Survivin (BIRC5) cell cycle computational network in human no-tumor hepatitis/cirrhosis and hepatocellular carcinoma transformation

Survivin (BIRC5) relationship with tumor is presented in several papers. However, how the molecular network and interpretation concerning BIRC5 cell cycle between no-tumor hepatitis/cirrhosis and hepatocellular carcinoma (HCC) remains to be elucidated. Here, we constructed and analyzed significant higher expression gene BIRC5 activated and inhibited cell cycle network from HCC versus no-tumor hepatitis/cirrhosis patients (viral infection HCV or HBV) in GEO Dataset by combination of gene regulatory network inference method based on linear programming and decomposition procedure with the CapitalBio MAS 3.0 software based on the integration of public databases including Gene Ontology, KEGG, BioCarta, GenMapp, Intact, UniGene, OMIM, etc. Compared the same and different activated and inhibited BIRC5 network with GO analysis between no-tumor hepatitis/cirrhosis and HCC, our result showed BIRC5 cell cycle network weaker transcription factor activity in both no-tumor hepatitis/cirrhosis and HCC (1); stronger nucleus protein binding but weaker cytoplasm protein binding in no-tumor hepatitis/cirrhosis (2); stronger cytoplasm protein phosphatase binding but weaker ubiquitin-protein ligase activity in HCC (3). Therefore, we inferred BIRC5 cell cycle module less transcription from RNA polymerase II promoter in both no-tumor hepatitis/cirrhosis and HCC (4). We deduced BIRC5 cell cycle module different from more mitosis but less complex-dependent proteasomal ubiquitin-dependent protein catabolism as a result increasing cell division and cell numbers in no-tumor hepatitis/cirrhosis to more protein amino acid autophosphorylation but less negative regulation of ubiquitin ligase activity during mitotic cell cycle as a result increasing growth and cell volume in HCC (5).

Survivin-mediated cancer cell migration through GRP78 and epithelial-mesenchymal transition (EMT) marker expression in Mahlavu cells

BACKGROUND

Survivin has multiple functions during the progression of cancer. However, the role of survivin in the progression and metastasis of hepatocellular carcinoma (HCC) remains unknown.

MATERIALS AND METHODS

Survivin expression in HCC cells (Mahlavu and Hep3B) was assessed using reverse transcription real-time PCR and Western blot analyses. In addition, survivin expression in HCC cells was manipulated using small interfering RNA (siRNA) or overexpression and proliferation and transwell migration assays were performed to monitor the effect of manipulated survivin expression on the growth rate and migratory ability of the transfected cells.

RESULTS

Among the HCC cell lines tested, we found high endogenous expression of survivin mRNA and protein in Mahlavu cells. After silencing survivin expression in Mahlavu cells, there was a dramatic decrease in the cell growth rate and an increase in the metastatic potential of the cells. Overexpression of survivin in Hep3B cells suppressed the ability of the cell to migrate. The mechanism of enhanced cell migration caused by decreased survivin expression is mediated through the downregulation of glucose-regulated protein 78 (GRP78) and the upregulation of the epithelial-mesenchymal transition (EMT) marker, vimentin.

CONCLUSIONS

Survivin may mediate metastasis in HCC. The knockdown of survivin expression may enhance cancer metastasis through the downregulation of GRP78 and upregulation of vimentin expression.

Survivin knockdown by short hairpin RNA abrogates the growth of human hepatocellular carcinoma xenografts in nude mice

Abnormal high activation of survivin is involved in carcinogenesis of various types of cancer. Survivin has been shown to promote cell proliferation in human hepatocellular carcinoma (HCC). Survivin-targeting approaches have become a promising strategy for treating HCC. Here, we used a reporter system to screen effective survivin siRNA sequences. The effect of vector-based survivin short hairpin RNA (shRNA) on the malignant phenotype of HCC cells in vitro and in vivo was determined, and an adenovirus-mediated shRNA expression vector was developed to decrease survivin expression of the established HCC tumor in nude mice. In vitro study showed that stable survivin knockdown inhibited cancer cell proliferation, enhanced apoptotic susceptibility, arrested cell cycle in the G1 phase and resulted in apparent mitotic catastrophe. Moreover, cells stably expressing survivin shRNA showed decreased tumorigenicity in nude mice. An additional in vivo study showed that intratumoral injection of adenovirus-delivered survivin shRNA suppressed tumor growth by spontaneous apoptosis of cancer cells and significantly prolonged animal survival. In conclusion, we proved the therapeutic potential of survivin shRNA for the treatment of HCC. And our results indicated that adenovirus-delivered shRNA may serve as a novel therapeutic for HCC.

Overcoming biological barriers to in vivo efficacy of antisense oligonucleotides

Antisense oligonucleotides as a therapeutic platform have been slow to progress since the approval of the first antisense drug in 1998. Recently, there have been several examples of convincing antisense interventions in animal models and promising clinical trial data. This review considers the factors determining the success of antisense oligonucleotides as therapeutic agents. In order to produce target knockdown after systemic delivery, antisense oligonucleotides must avoid nuclease degradation, reticuloendothelial-system uptake and rapid renal excretion, and extravasate to the target cell type outside the vasculature. They then must enter the target cell, and escape the endosome-lysosome pathway so as to be free to interact with the target mRNA. We consider the significance of these limiting factors based on the literature and our own experience using systemic administration of antisense oligonucleotides.

Melatonin induces cell cycle arrest and apoptosis in hepatocarcinoma HepG2 cell line

Melatonin reduces proliferation in many different cancer cell lines. However, studies on the oncostatic effects of melatonin in the treatment of hepatocarcinoma are limited. In this study, we examined the effect of melatonin administration on HepG2 human hepatocarcinoma cells, analyzing cell cycle arrest, apoptosis and mitogen-activated protein kinase (MAPK) signalling pathways. Melatonin was dissolved in the cell culture media in 0.2% dimethyl sulfoxide and administered at different concentrations for 2, 4, 6, 8 and 10 days. Melatonin at concentrations 1000-10,000 microM caused a dose- and time-dependent reduction in cell number. Furthermore, melatonin treatment induced apoptosis with increased caspase-3 activity and poly(ADP-ribose) polymerase proteolysis. Proapoptotic effects of melatonin were related to cytosolic cytochrome c release, upregulation of Bax and induction of caspase-9 activity. Melatonin treatment also resulted in increased caspase-8 activity, although no significant change was observed in Fas-L expression. In addition, JNK 1,-2 and -3 and p38, members of the MAPK family, were upregulated by melatonin treatment. Growth inhibition by melatonin altered the percentage or cells in G0-G1 and G2/M phases indicating cell cycle arrest in the G2/M phase. The reduced cell proliferation and alterations of cell cycle were coincident with a significant increase in the expression of p53 and p21 proteins. These novel findings show that melatonin, by inducing cell death and cell cycle arrest, might be useful as adjuvant in hepatocarcinoma therapy.