Xiumei Zhou

Augmenting the Antitumor Effect of TRAIL by SOCS3 with Double-Regulated Replicating Oncolytic Adenovirus in Hepatocellular Carcinoma

Aberrant JAK/STAT3 pathway has been reported to be related to hepatocellular carcinoma (HCC) in many cell lines. In this study, a double-regulated oncolytic adenovirus vector that can replicate and induce a cytopathic effect in alpha-fetoprotein (AFP)-positive HCC cell lines with p53 dysfunction was successfully constructed. Two therapeutic genes, suppressor of cytokine signaling 3 (SOCS3) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were chosen and incorporated into this vector system, respectively. The combined treatment of AFP-D55-SOCS3 and AFP-D55-TRAIL (2:3 ratio) exhibited potent antitumor activity in AFP-positive HCC cell lines compared with any other treatment both in vitro and in vivo. Specific replication and low progeny yield in AFP-positive HCC cell lines rendered these double-regulated oncolytic adenoviruses remarkably safe. Our data demonstrated that restoration of SOCS3, which inhibits the JAK/STAT3 pathway, by AFP-D55-SOCS3 not only could antagonize HCC therapeutic resistance to TRAIL and adenoviruses, but could also induce cell cycle arrest in HCC cell lines. SOCS3 could down-regulate Cyclin D1 and anti-apoptotic proteins such as XIAP, Survivin, Bcl-xL, and Mcl-1, which are responsible for the synergistic inhibitory effects of AFP-D55-SOCS3 and AFP-D55-TRAIL. Dual gene and double-regulated oncolytic adenoviruses may provide safety and excellent antitumor effects for liver cancer, which is the advantage of a cancer-targeting gene virotherapy strategy.

Overexpression of tumor suppressor TSLC1 by a survivin-regulated oncolytic adenovirus significantly inhibits hepatocellular carcinoma growth.

PurposeHepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Oncolytic viruses represent a promising therapeutic agent or vehicle to human cancers due to their ability of selectively lysing cancer cells but not in normal cells. TSLC1, a novel tumor suppressor gene, was loss in many human cancers including HCC, not in normal cells. The current study is focused on the antitumor effect of TSLC1-armed survivin-regulated oncolytic adenovirus for HCC and to explore their molecular mechanism.MethodsThe expression of tumor suppressor TSLC1 and survivin was detected by quantitative PCR. The recombinant virus Ad.SP-E1A-E1B(Δ55)-TSLC1 (brief name as SD55-TSLC1) was constructed by inserting TSLC1 gene into the dual-regulated oncolytic adenovirus vector Ad.SP-E1A-E1B(Δ55). Then, we performed the antitumor experiments of SD55-TSLC1 in vitro and in nude mice xenografted with Huh7 liver cancer.ResultsThe expression of TSLC1 was lower in HCC cells than in normal cells, which implied TSLC1 is a tumor suppressor of liver cancer. Survivin expression is higher in detected HCC cells than in normal cells. The SD55-TSLC1 exhibited an excellent antitumor effect on HCC cell growth in vitro but does no or little damage to normal liver cells. Animal experiment further confirmed that SD55-TSLC1 achieved significant inhibition of Huh7 liver cancer xenografted growth. Furthermore, the mechanism of antitumor efficacy by SD55-TSLC1 was elucidated to be due to the activation of caspase apoptotic pathway including the inducement of caspase-3, caspase-8, and poly (ADP-ribose) polymerase cleavage. This is the first report of TSLC1 by oncolytic adenovirus with an excellent antitumor effect to liver cancer growth.ConclusionThese data suggest that an oncolytic adenovirus expressing TSLC1 is effective and support that SD55-TSLC1 may be a potent antitumoral agent for future clinical trials of liver cancer.

Synergistic suppression effect on tumor growth of hepatocellular carcinoma by combining oncolytic adenovirus carrying XAF1 with cisplatin.

PurposeThe potent anticancer efficacy of oncolytic viruses has been verified in Clinic in recent years. Cisplatin (DDP) is one of most common chemotherapeutic drugs, but is accompanied by side effects and drug resistance. Our previous studies have shown the strategy of cancer -targeting gene-viro-therapy (CTGVT) mediated by the oncolytic virus ZD55 containing the XAF1 cDNA (ZD55-XAF1), which exhibited potent antitumor effects in various tumor cells and no apparent toxicities on normal cells. In the study, the CTGVT strategy is broadened by combining DDP with ZD55-XAF1 for growth inhibition of hepatocellular carcinoma (HCC) cells.MethodsThe transgenic expression was evaluated by both in vitro and in vivo experiments, and the enhanced inhibitory effect of ZD55-XAF1 combined with cisplatin was assessed in HCC cells. The cytotoxicity on normal liver cells was evaluated by MTT assay and apoptotic cell staining. Activation of caspase-9 and PARP for apoptosis was further detected by Western blot analysis. The in vivo antitumor efficacy of combination treatment with cisplatin and ZD55-XAF1 was estimated in an HCC xenograft mouse model.ResultsWe found that the combination of ZD55-XAF1 and cisplatin showed enhanced inhibitory effects on the proliferation of HCC cells in vitro and tumor growth in mice. Furthermore, the combined treatment of ZD55-XAF1 and DDP decreases the chemotherapy dose needed to achieve the same inhibitory effect without overlapping toxicities on normal liver cells and induces tumor cell apoptosis via the activation of caspase-9/PARP pathway.ConclusionThus, these data suggest that the chemo-gene-viro-therapeutic strategy by combining ZD55-XAF1 and DDP reveals a novel therapeutic strategy for hepatocellular carcinoma.

A new oncolytic adenoviral vector carrying dual tumour suppressor genes shows potent anti-tumour effect

Cancer Targeting Gene‐Viro‐Therapy (CTGVT) is a promising cancer therapeutical strategy that strengthens the anti‐tumour effect of oncolytic virus by expressing inserted foreign anti‐tumour genes. In this work, we constructed a novel adenoviral vector controlled by the tumour‐specific survivin promoter on the basis of the ZD55 vector, which is an E1B55KD gene deleted vector we previously constructed. Compared with the original ZD55 vector, this new adenoviral vector (ZD55SP/E1A) showed much better ability of replication and reporter gene expression. We then combined anti‐tumour gene interleukine‐24 (IL‐24) with an RNA polymerase III‐dependent U6 promoter driving short hairpin RNA (shRNA) that targets M‐phase phosphoprotein 1 (MPHOSPH1, a newly identified oncogene) by inserting the IL‐24 and the shRNA of MPHOSPH1 (shMPP1) expression cassettes into the new ZD55SP/E1A vector. Our results demonstrated excellent anti‐tumour effect of ZD55SP/E1A‐IL‐24‐shMPP1 in vitro on multiple cancer cell lines such as lung cancer, liver cancer and ovarian caner. At high multiplicity‐of‐infection (MOI), ZD55SP/E1A‐IL‐24‐shMPP1 triggered post‐mitotic apoptosis in cancer cells by inducing prolonged mitotic arrest; while at low MOI, senescence was induced. More importantly, ZD55SP/E1A‐IL‐24‐shMPP1 also showed excellent anti‐tumour effects in vivo on SW620 xenograft nude mice. In conclusion, our strategy of constructing an IL‐24 and shMPP1 dual gene expressing oncolytic adenoviral vector, which is regulated by the survivin promoter and E1B55KD deletion, could be a promising method of cancer gene therapy.

Targeting adeno-associated virus and adenoviral gene therapy for hepatocellular carcinoma

Human hepatocellular carcinoma (HCC) heavily endangers human heath worldwide. HCC is one of most frequent cancers in China because patients with liver disease, such as chronic hepatitis, have the highest cancer susceptibility. Traditional therapeutic approaches have limited efficacy in advanced liver cancer, and novel strategies are urgently needed to improve the limited treatment options for HCC. This review summarizes the basic knowledge, current advances, and future challenges and prospects of adeno-associated virus (AAV) and adenoviruses as vectors for gene therapy of HCC. This paper also reviews the clinical trials of gene therapy using adenovirus vectors, immunotherapy, toxicity and immunological barriers for AAV and adenoviruses, and proposes several alternative strategies to overcome the therapeutic barriers to using AAV and adenoviruses as vectors.

Complete Eradication of Xenograft Hepatoma by Oncolytic Adenovirus ZD55 Harboring TRAIL-IETD-Smac Gene with Broad Antitumor Effect

Cancer-targeting dual-gene virotherapy (CTGVT-DG) is an important modification of CTGVT, in which two suitable genes are used to obtain an excellent antitumor effect. A key problem is to join the two genes to form one fused gene, and then to clone it into the oncolytic viral vector so that only one investigational new drug application, instead of two, is required for clinical use. Many linkers (e.g., internal ribosome entry site) are used to join two genes together, but they are not all equally efficacious. Here, we describe finding the best linker, that is, sequence encoding the four amino acids IETD, to join the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and the second mitochondria-derived activator of caspase (Smac) gene to form TRAIL-IETD-Smac and inserting it into oncolytic viral vector ZD55 to construct ZD55-TRAIL-IETD-Smac, which matched ZD55-TRAIL plus ZD55-Smac in completely eliminating xenograft hepatoma. ZD55-TRAIL-IETD-Smac works by quantitative cleavage at IETD↓by inducing caspase-8; activation or inhibition of caspase-8 could up- or downregulate cleavage, respectively. The cleaved product, TRAIL-IETD, does not affect the function of TRAIL. Numerous experiments have shown that the combined use of ZD55-TRAIL plus ZD55-X could completely eradicate many xenograft tumors, and therefore the IETD is potentially a useful linker to construct many antitumor drugs, for example, ZD55-TRAIL-IETD-X, where X has a compensative or synergetic effect on TRAIL. We found that the antitumor effect of ZD55-IL-24-IETD-TRAIL also has an equivalent antitumor effect compared with the combined use of ZD55-IL-24 plus ZD55-TRAIL, because ZD55-IL-24 could also induce caspase-8. This means that IETD, as a two-gene linker, may have broad use.

Tumor suppressor in lung cancer-1 (TSLC1) mediated by dual-regulated oncolytic adenovirus exerts specific antitumor actions in a mouse model

Aim:The tumor suppressor in lung cancer-1 (TSLC1) is a candidate tumor suppressor of lung cancer, and frequently inactivated in primary non-small cell lung cancer (NSCLC). In this study, we investigated the effects of TSLC1 mediated by a dual-regulated oncolytic adenovirus on lung cancer, and the mechanisms underlying the antitumor actions.Methods:The recombinant virus Ad·sp-E1A(Δ24)-TSLC1 was constructed by inserting the TSLC1 gene into the dual-regulated Ad·sp-E1A(Δ24) vector, which contained the survivin promoter and a 24 bp deletion within E1A. The antitumor effects of Ad·sp-E1A(Δ24)-TSLC1 were evaluated in NCI-H460, A549, and H1299 lung cancer cell lines and the normal fibroblast cell line MRC-5, as well as in A549 xenograft model in nude mice. Cell viability was assessed using MTT assay. The expression of TSLC1 and activation of the caspase signaling pathway were detected by Western blot analyses. The tumor tissues from the xenograft models were examined using H&E staining, IHC, TUNEL, and TEM analyses.Results:Infection of A549 lung cancer cells with Ad·sp-E1A(Δ24)-TSLC1 induced high level expression of TSLC1. Furthermore, the Ad·sp-E1A(Δ24)-TSLC1 virus dose-dependently suppressed the viability of NCI-H460, A549, and H1299 lung cancer cells, and did not affect MRC-5 normal fibroblast cells. Infection of NCI-H460, A549, and H1299 lung cancer cells with Ad·sp-E1A(Δ24)-TSLC1 induced apoptosis, and increased activation of caspase-8, caspase-3 and PARP. In A549 xenograft model in nude mice, intratumoral injection of Ad·sp-E1A(Δ24)-TSLC1 significantly suppressed the tumor volume, and increased the survival rate (from less than 15% to 87.5% at d 60). Histological studies showed that injection of Ad·sp-E1A(Δ24)-TSLC1 caused tumor cell apoptosis and virus particle propagation in tumor tissues.Conclusion:The oncolytic adenovirus Ad·sp-E1A(Δ24)-TSLC1 exhibits specific antitumor effects, and is a promising agent for the treatment of lung cancer.

Potent and Specific Antitumor Effect for Colorectal Cancer by CEA and Rb Double Regulated Oncolytic Adenovirus Harboring ST13 Gene

Cancer Targeting Gene-Viro-Therapy (CTGVT) is constructed by inserting an antitumor gene into an oncolytic virus (OV). It is actually an OV-gene therapy, which has much better antitumor effect than either gene therapy alone or virotherapy alone in our previously published papers. This study is a modification of CTGVT by inserting a colorectal cancer (CRC) specific suppressor gene, ST13, into a CRC specific oncolytic virus, the Ad·CEA·E1A(Δ24), to construct the Ad·(ST13)·CEA·E1A(Δ24) for increasing the targeting tropism to colorectal cancer and it was briefly named as CTGVT-CRC. Although many studies on CEA promoter and ST13 gene were reported but no construct has been performed to combine both of them as a new strategy for colorectal cancer (CRC) specific therapy. In addition to the CRC specificity, the antitumor effect of Ad·(ST13)·CEA·E1A(Δ24) was also excellent and got nearly complete inhibition (not eradication) of CRC xenograft since ST13 was an effective antitumor gene with less toxicity, and a Chinese patent (No. 201110319434.4) was available for this study. Ad·(ST13)·CEA·E1A(Δ24) caused cell apoptosis through P38 MAPK (i.e. P38) which upregulated CHOP and ATF2 expression. The mitochondrial medicated apoptosis pathway was activated by the increase of caspase 9 and caspase 3 expression.

GP73-regulated oncolytic adenoviruses possess potent killing effect on human liver cancer stem-like cells

Cancer stem cells (CSCs), also known as tumor-initiating cells, are highly metastatic, chemo-resistant and tumorigenic, and are critical for cancer development, maintenance and recurrence. Oncolytic adenovirus could targetedly kill CSCs and has been acted as a promising anticancer agent. Currently, a novel GP73-regulated oncolytic adenovirus GD55 was constructed to specifically treat liver cancer and exhibited obvious cytotoxicity effect. However, there remains to be confirmed that whether GD55 could effectively eliminate liver CSCs. We first utilized the suspension culture to enrich the liver CSCs-like cells, which acquires the properties of liver CSCs in self-renewal, differentiation, quiescence, chemo-resistance and tumorigenicity. The results indicated that GD55 elicited more significant cytotoxicity and stronger oncolytic effect in liver CSC-like cells compared to common oncolytic virus ZD55. Additionally, GD55 possessed the greater efficacy in suppressing the growth of implanted tumors derived from liver CSC-like cells than ZD55. Furthermore, GD55 induced remarkable apoptosis of liver CSC-like cells in vitro and in vivo, and inhibited the propogation of cells and angiogenesis in xenograft tumor tissues. Thus, GD55 may virtually represent an attractive therapeutic agent for targeting liver CSCs to achieve better clinical outcomes for HCC patients.

Interferon-related secretome from direct interaction between immune cells and tumor cells is required for upregulation of PD-L1 in tumor cells

PD-L1, also known as CD274, plays a vital role in tumor cell related immune escape. It can be expressed on the cell surface of many solid tumors (Brahmer et al., 2012) and inhibits T cell proliferation and cytokine production by binding to the Tcell surface receptor programmed death 1 (PD-1) or B7-1 (McClanahan et al., 2015). In 2013, targeting PD-1/ PD-L1 signaling for cancer immunotherapy was selected as the No.1 scientific breakthrough of the year by the editors of Science. Interferons (IFNs) are a group of pleiotropic cytokines, demonstrated anti-viral, anti-tumor, and immune regulatory functions (York et al., 2015). Type I interferon binds a heterodimeric receptor composed of IFNAR1 and IFNAR2. This activates a canonical JAK/STAT signaling pathway that ultimately induces a set of interferon-stimulated genes to exert its biological activity (Ejlerskov et al., 2015). Recently, PD-L1 was reported to be downstream of IFN signaling in human oral squamous carcinoma, melanoma, and human acute myeloid leukemia blast cells (Chen et al., 2012; Furuta et al., 2014; Kronig et al., 2014). The tumor microenvironment plays an important role in tumor growth and metastasis. Different components of the tumor microenvironment such as T cells, B cells, NK cells, dendritic cells, mast cells, granulocytes, Treg cells, myeloid derived suppressor cells (MDSC), and tumor associated macrophages (TAM) are recruited by different pathways (Joyce and Fearon, 2015). Tumor cells have been shown to upregulate PD-L1 after interacting with infiltrating immune cells (Cho et al., 2011; Hou et al., 2014), but the mechanism by which this occurs is not well understood. In this study, we found that PD-L1 upregulation in tumors was dependent on direct interaction with immune cells and was driven by a secreted factor such as type I interferon after cell-cell contact. Previous studies have demonstrated a positive correlation between tumor-infiltrating immune cells and elevated PD-L1 expression in tumor cells, but the mechanism by which this occurs is poorly understood. To investigate this, we co-cultured murine B16F10 melanoma cells with syngeneic splenocytes for 48 h. In addition, to determine whether direct cell contact is required for immune cell-mediated PD-L1 expression, the two types of cells were separated by a transwell-membrane that blocked their direct cell-cell interactions. Furthermore, another condition was tested in which B16F10 cells and immune cells were co-cultured in the plate and B16F10 cells were cultured in the transwell insert (Fig. 1A). Then the non-adherent immune cells were removed and B16F10 cells were harvested and analyzed for PD-L1 expression by flow cytometry. PD-L1 was more highly expressed in B16F10 cells that were co-cultured with splenocytes than in those cultured alone (Fig. 1B). However, PD-L1 expression was not increased in B16F10 cells separated from the splenocytes by a transwell membrane. We also found that a B16F10-splenocyte co-culture was able to induce PD-L1 in tumor cells separated from the co-culture by a transwell membrane (Fig. 1B). These effects were also observed in PD-L1 mRNA level changes by qPCR (Fig. 1C). These results suggested that active factors were secreted into the supernatant after the direct cell-cell interaction that was able to induce PD-L1 expression in tumor cells. To identify whether the regulation of PD-L1 was indeed driven by a secreted factor, B16F10 cells and splenocytes were co-cultured for 48 h. The supernatant was collected and centrifuged, and then used to treat B16F10 cells independently. The corresponding supernatant derived from B16F10 cells and splenocytes alone was also used to treat B16F10 cells as control groups (Fig. 1D). After 24 h, B16F10 cells treated with supernatant from the co-culture expressed more PD-L1 than cells treated with supernatant from the control mono-cultures (Fig. 1E and 1F). In addition, co-cultures of B16F10 cells with bone marrow (BM)-derived cells (Fig. 1G) or lymph node (LN)-derived cells also upregulated PD-L1 expression (Fig. 1H). To determine whether a similar effect would be seen in other types of cancer cells, additional studies on MC38 and Hepa1-6 cells