Overexpression of soluble TRAIL induces apoptosis in human lung adenocarcinoma and inhibits growth of tumor xenografts in nude mice

Targeting Apoptosis in Cancer

PURPOSE OF REVIEW

Apoptosis is a major mechanism of cancer cell death. Thus, evasion of apoptosis results in therapy resistance. Here, we review apoptosis modulators in cancer and their recent developments, including MDM2 inhibitors and kinase inhibitors that can induce effective apoptosis.

RECENT FINDINGS

Both extrinsic pathways (external stimuli through cell surface death receptor) and intrinsic pathways (mitochondrial-mediated regulation upon genotoxic stress) regulate the complex process of apoptosis through orchestration of various proteins such as members of the BCL-2 family. Dysregulation within these complex steps can result in evasion of apoptosis. However, via the combined evolution of medicinal chemistry and molecular biology, omics assays have led to innovative inducers of apoptosis and inhibitors of anti-apoptotic regulators. Many of these agents are now being tested in cancer patients in early-phase trials. We believe that despite a sluggish speed of development, apoptosis targeting holds promise as a relevant strategy in cancer therapeutics.

GPX4-Regulated Ferroptosis Mediates S100-Induced Experimental Autoimmune Hepatitis Associated with the Nrf2/HO-1 Signaling Pathway

Autoimmune hepatitis (AIH) is an inflammatory autoimmune disease of the liver. Oxidative stress triggered by reactive oxygen radicals is a common pathophysiological basis for the pathogenesis of many liver diseases, and ferroptosis is associated with the toxic accumulation of reactive oxygen species. The signaling transduction pathways responsible for iron processing and lipid-peroxidation mechanisms are believed to drive ferroptosis. However, the specific mechanisms regulating ferroptosis remain unclear. The aims of this investigation were to identify the possible effector functions of ferroptosis, based on glutathione peroxidase 4 (GPX4) regulation in an S100-induced autoimmune hepatitis mouse model and hepatocyte injury models. The S100 liver antigen-induced AIH mouse model was used to detect ferroptotic biomarkers using western blotting. Upregulated levels of cyclooxygenase2 (COX2) and Acyl-Coenzyme A synthase long-chain family member 4 (ACSL4) were observed in the S100-induced AIH model group, while levels of GPX4 and ferritin heavy chain 1 (FTH1) were downregulated (P < 0.05). The expression profiles of COX2, ACSL4, GPX4, and FTH1 were restored following the administration of ferrostatin-1. In addition, Nrf2 and HO-1 levels in the S100-induced AIH model mice after treatment with ferrostatin-1 were downregulated compared to the nonferrostatin-1-treated S100-induced AIH model mice (P < 0.05). Moreover, COX2 and ACSL4 levels were significantly upregulated, with significant FTH1 downregulation, in the AIH model mice when liver-specific GPX4 was silenced using AAV8 constructs. These data indicate that inhibition of ferroptosis significantly ameliorated the influence of AIH on the Nuclear factor E2-related factor 2 (Nrf2)/Heme oxygenase-1 (HO-1) signaling pathway, and that ferroptosis may act as an initiator or intermediate mediator leading to AIH.

Doxorubicin hydrochloride enhanced antitumour effect of CEA-regulated oncolytic virotherapy in live cancer cells and a mouse model

Oncolytic adenovirus (OA) has attracted increasing attention due to their specific proliferation in tumour cells and resulting in lysis of tumour cells. To further improve the antitumour effect of OA, in this study, we combined CD55-TRAIL-IETD-MnSOD (CD55-TMn), a CEA-controlled OA constructed previously, and chemotherapy to investigate their synergistic effect and possible mechanisms. MTT assay was performed to detect antitumour effects. Hoechst 33 342 and flow cytometric analysis were used to examine cell apoptosis. Western blotting was performed to examine cell pyroptosis and apoptosis mechanism. Animal experiment was used to detect antitumour effect of doxorubicin hydrochloride (Dox) combined with CD55-TMn in vivo. We firstly found that Dox promotes gene expression mediated by CEA-regulated OA and virus progeny replication by activating phosphorylation of Smad3, and Dox can enhance antitumour effect of CEA-regulated CD55-TMn by promoting cell apotopsis and cell pyroptosis. Thus, our results provide an experimental and theoretical basis on tumour therapy by combination treatment of the oncolytic virotherapy and chemotherapy and it is expected to become a novel strategy for liver cancer therapy.

Towards Clinical Implementation of Adeno-Associated Virus (AAV) Vectors for Cancer Gene Therapy: Current Status and Future Perspectives

Adeno-associated virus (AAV) vectors have gained tremendous attention as in vivo delivery systems in gene therapy for inherited monogenetic diseases. First market approvals, excellent safety data, availability of large-scale production protocols, and the possibility to tailor the vector towards optimized and cell-type specific gene transfer offers to move from (ultra) rare to common diseases. Cancer, a major health burden for which novel therapeutic options are urgently needed, represents such a target. We here provide an up-to-date overview of the strategies which are currently developed for the use of AAV vectors in cancer gene therapy and discuss the perspectives for the future translation of these pre-clinical approaches into the clinic.

Antioxidant, Hypolipidemic and Hepatic Protective Activities of Polysaccharides from Phascolosoma esculenta

The aims of this study were to investigate the antioxidant, hypolipidemic and hepatic protective effects of Phascolosoma esculenta polysaccharides (PEP). PEP was prepared from Phascolosoma esculenta by enzyme hydrolysis and its characterization was analyzed. The antioxidant activities of PEP were evaluated by the assays of scavenging 1,1-Diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydroxyl radicals and chelating ferrous ion in vitro. It showed that PEP could scavenge radicals effectively and had favorable antioxidant activities. In the meantime, the hypolipidemic effect of PEP was investigated in vivo by using mice model fed with high-fat diet with or without PEP treatment. Compared with the hyperlipidemic mice without treatment, the serum levels of total cholesterol (TC) (30.1–35.7%, p < 0.01), triglyceride (TG) (24.5–50.8%, p < 0.01 or p < 0.05), low-density lipoprotein cholesterol (LDL-C) (49.6–56.8%, p < 0.01) and liver levels of TC (21.0–28.4%, p < 0.01), TG (23.8–37.0%, p < 0.01) decreased significantly, whereas serum high-density lipoprotein cholesterol (HDL-C) (47.7–59.9%, p < 0.01 or p < 0.05) increased significantly after treatment with different dosage of PEP (0.2, 0.4 and 0.8 g per kg body weight, respectively). In addition, superoxide dismutase (SOD) (10.2–22.2% and 18.8–26.9%, p < 0.05), glutathione peroxidase (GSH-Px) (11.9–15.4% and 26.6–30.4%, p < 0.05) activities in serum and liver enhanced markedly while aspartate aminotransferase (AST) (18.7–29.6% and 42.4–58.0%, p < 0.05), alanine transaminase (ALT) (42.7–46.0% and 31.2–42.2%, p < 0.05) activities, as well as the levels of malondialdehyde (MDA) (15.9–24.4% and 15.0–16.8%, p < 0.01 or p < 0.05) in serum and liver reduced markedly. Moreover, the histopathological observation of livers indicated that PEP could attenuate liver cell injury. The animal experimental results demonstrated that PEP exerted hypolipidemic and hepatoprotective roles in hyperlipidemic mice. In summary, our results above suggest that PEP might be a potential natural antioxidant and utilized as a therapeutic candidate for hyperlipidemia.

microRNA-143-3p attenuated development of hepatic fibrosis in autoimmune hepatitis through regulation of TAK1 phosphorylation

Autoimmune hepatitis (AIH) is a chronic liver disease due to autoimmune system attacks hepatocytes and causes inflammation and fibrosis. Intracellular signalling and miRNA may play an important role in regulation of liver injury. This study aimed to investigate the potential roles of microRNA 143 in a murine AIH model and a hepatocyte injury model. Murine AIH model was induced by hepatic antigen S100, and hepatocyte injury model was induced by LPS. Mice and AML12 cells were separated into six groups with or without the treatment of miRNA-143. Inflammation and fibrosis as well as gene expression were examined by different cellular and molecular techniques. The model was successfully established with the elevation of ALT and AST as well as inflammatory and fibrotic markers. Infection or transfection of mir-143 in mice or hepatocytes significantly attenuated the development of alleviation of hepatocyte injury. Moreover, the study demonstrated phosphorylation of TAK1-mediated miRNA-143 regulation of hepatic inflammation and fibrosis as well as hepatocyte injury. Our studies demonstrated a significant role of miRNA-143 in attenuation of liver injury in AIH mice and hepatocytes. miRNA-143 regulates inflammation and fibrosis through its regulation of TAK1 phosphorylation, which warrants TAK1 as a target for the development of new therapeutic strategy of autoimmune hepatitis.

Combination of the natural compound Periplocin and TRAIL induce esophageal squamous cell carcinoma apoptosis in vitro and in vivo: Implication in anticancer therapy

BACKGROUND

Esophageal cancer is one of the most common malignant tumors in the world. With currently available therapies, only 20% ~ 30% patients can survive this disease for more than 5 years. TRAIL, a natural ligand for death receptors that can induce the apoptosis of cancer cells, has been explored as a therapeutic agent for cancers, but it has been reported that many cancer cells are resistant to TRAIL, limiting the potential clinical use of TRAIL as a cancer therapy. Meanwhile, Periplocin (CPP), a natural compound from dry root of Periploca sepium Bge, has been studied for its anti-cancer activity in a variety of cancers. It is not clear whether CPP and TRAIL can have activity on esophageal squamous cell carcinoma (ESCC) cells, or whether the combination of these two agents can have synergistic activity.

METHODS

We used MTS assay, flow cytometry and TUNEL assay to detect the effects of CPP alone or in combination with TRAIL on ESCC cells. The mechanism of CPP enhances the activity of TRAIL was analyzed by western blot, dual luciferase reporter gene assay and chromatin immunoprecipitation (ChIP) assay. The anti-tumor effects and the potential toxic side effects of CPP alone or in combination with TRAIL were also evaluated in vivo.

RESULTS

In our studies, we found that CPP alone or in combination with TRAIL could inhibit the proliferation of ESCC cells and induce apoptosis, and we certificated that combination of two agents exert synergized functions. For the first time, we identified FoxP3 as a key transcriptional repressor for both DR4 and DR5. By down-regulating FoxP3, CPP increases the expression of DR4/DR5 and renders ESCC cells much more sensitive to TRAIL. We also showed that CPP reduced the expression of Survivin by inhibiting the activity of Wnt/β-catenin pathway. All these contributed to synergistic activity of CPP and TRAIL on ESCC cells in vitro and in vivo.

CONCLUSION

Our data suggest that CPP and TRAIL could be further explored as potential therapeutic approach for esophageal cancer.

Development of a hybrid nanocarrier-recognizing tumor vasculature and penetrating the BBB for glioblastoma multi-targeting therapy

The success of glioma chemotherapy is hampered by poor drug penetration ability across the blood-brain barrier (BBB) and low intratumoral drug concentration. Novel tumor-targeted delivery systems are useful in specifically accumulating in the tumor foci and penetrating into the glioma core after entering into the brain. Here we show that a multi-targeting hybrid nanocarrier (Pep-MLHA HNPs) system based on hyaluronic acid (HA)-modified polymer and a functional peptide possesses multi-target capability and stronger penetration ability into the core of three-dimensional tumor spheroids, could migrate efficiently across the BBB in vitro. The intensity of the Pep-MLHA HNPs after transporting across the BBB was 5.2-fold and 5.6-fold higher than that of ML NPs in C6 and U87 cells, respectively. More interestingly, this multi-targeting hybrid system displayed high colloidal stability in PBS solution, and weak negative zeta potential (-1.99 ± 0.655 mV) minimizing nonspecific interactions with plasma proteins and promoting long-term circulation in vivo. Additionally, the multi-targeting hybrid system induced enhanced tumor localization in U87 in situ-bearing nude mice and xenograft-bearing nude mice after systemic administration. Furthermore, docetaxel (DTX)-loaded Pep-MLHA HNPs showed negligible systemic toxicity and enhanced therapeutic efficacy, with significantly improved survival rates in intracranial C6 glioma-bearing rats. The 50% survival rate of DTX/Pep-MLHA HNPs-treated rats (40 days) was significantly longer than that of rats treated with NS (22 days), Taxotere® (25 days), DTX/ML NPs (25 days), DTX/Pep NPs (32 days) and DTX/MLHA NPs (29 days). All the results suggested that the multi-targeting hybrid nanocarrier system is promising for glioma treatment.

Interferon beta increases NK cell cytotoxicity against tumor cells in patients with nasopharyngeal carcinoma via tumor necrosis factor apoptosis-inducing ligand

BACKGROUND

Nasopharyngeal carcinoma (NPC) is an EBV-associated neoplasm occurring endemically in Southeast Asia and sporadically all over the world. In children and adolescents, high cure rates have been obtained using chemotherapy, radiochemotherapy and maintenance therapy with interferon beta (IFNβ). The mechanism by which IFNβ contributes to a low systemic relapse rate has not yet been fully revealed.

PATIENTS AND METHODS

NK cells and serum samples from two patients with NPC were analyzed before and at different time points during IFNβ therapy, for assessment of TRAIL expression and NK cell cytotoxicity. Cytotoxicity was measured using the calcein release assay and the contribution of different death effector pathways was analyzed using specific inhibitors.

RESULTS

Treatment with IFNβ induced TRAIL expression on patients' NK cells and increased their cytotoxicity against NPC targets in vitro. NK cell-mediated cytotoxicity was predominately mediated via TRAIL. IFNβ also induced the production of soluble TRAIL (sTRAIL) by NK cells and its release upon contact with NPC cells. IFNβ treatment increased serum levels of sTRAIL in patients. Moreover, sTRAIL concentrated from patients' serum samples induced apoptosis ex vivo in NPC cells from a patient-derived xenograft.

CONCLUSION

Increased cytotoxicity of NK cells against NPC cells and increased serum levels of biologically active TRAIL in patients treated with IFNβ could be a means to eliminate micrometastatic disease and explain the low systemic relapse rate in this patient group.

Chitosan for gene delivery: Methods for improvement and applications

Gene therapy is a promising strategy for treating challenging diseases. The successful delivery of genes is a critical step for gene therapy. However, concerns about immunogenicity and toxicity are the main obstacles against the widespread use of effective viral systems. Therefore, nonviral vectors are regarded as good alternatives to viral vectors. Chitosan is a natural cationic polysaccharide that could be used to create nonviral gene delivery vectors. Various methods have been developed to improve the properties of chitosan related to gene delivery. This review introduces the features of chitosan in gene delivery, summarizes current progress toward methods promoting the properties of chitosan related to gene delivery, and presents different applications of chitosan in gene delivery vectors. Finally, future prospects of gene vectors based on chitosan are discussed.

Chemotherapy-induced miR-141/MAP4K4 signaling suppresses progression of colorectal cancer

One of the treatment failures for colorectal cancer (CRC) is resistance to chemotherapy drugs. miRNAs have been demonstrated to be a new regulator of pathobiological processes in various tumors. While few studies have explored the specific role of miR-141 in mediating 5-fluorouracil (5-FU) sensitivity of CRC cells, the present study aimed to detect the contribution of miR-141 in 5-FU sensitivity. The CRC cells viability was measured by MTS assay and cell colony forming. The expression of miR-141 and its downstream targets were assessed by reverse transcription quantitative PCR, Western blotting, and immunohistochemistry. The functional assays were conducted using CRC cells and nude mice. At the present study, we found overexpression of miR-141 could inhibit proliferation, migration, tumor-forming and invasive potential of CRC cells in vitro and mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) was verified as a directed target of miR-141 The combination treatment of miR-141 with 5-FU, directly targetting MAP4K4, could better inhibit invasion and metastasis of CRC cells colony than either one alone. Furthermore, overexpression of miR-141, targetting MAP4K4, enhanced the effected of 5-FU and suppressed the malignant biological behaviors, in vivo Our findings showed that 5-FU inhibited malignant behavior of human CRC cells in vitro and in vivo by enhancing the efficiency of miR-141 Our data suggested that targetting the miR-141/MAP4K4 signaling pathway could be a potential molecular target that may enhance chemotherapeutic efficacy in the treatment of CRC.

Improved anti-colorectal carcinomatosis effect of tannic acid co-loaded with oxaliplatin in nanoparticles encapsulated in thermosensitive hydrogel

Tannic acid, a hydrolysable tannin, exists commonly in food plants. Tannic acid has already been shown various anticancer mechanisms such as inhibiting the proliferation, inducing a higher apoptotic rate and slowing down the metastasis of different cancers. Moreover, tannic acid was reported to reduce the side effects caused by chemotherapeutics on patients. But whether the tannic acid can improve the treatment of oxaliplatin on colorectal carcinomatosis has yet been studied. In this study, we developed an injectable drug delivery system by physical incorporation of oxaliplatin (OXA) and tannic acid (TA) polymeric nanoparticles (OXA/TA NPs) into a thermo-sensitive hydrogel, OXA/TA NPs-hydrogel (OXA/TA NPs-H). The OXA/TA NPs-H was injected into the peritoneal cavity for the treatment of colorectal peritoneal carcinoma. Firstly, a water-in-oil-in-water double-emulsion (w/o/w) method and solvent-evaporation procedure were used in the preparation of the biodegradable OXA/TA NPs. Then, we prepared the biodegradable thermo-sensitive poly(3-caprolactone) (PCL)-10R5-PCL (PCLR) hydrogel with a low critical solution temperature (LCST) which undergoes gelation process at body temperature. Transmission electron microscopy (TEM) showed the spherical profile of OXA/TA NPs. Fourier-transform infrared (FTIR) spectra demonstrated that OXA and TA were both encapsulated into the OXA/TA NPs. In this study, intraperitoneal application of OXA/TA NPs-H restricted the growth of CT26 peritoneal colon cancer in vivo, improved the quality of life and prolonged the survival time of the model mice. Our study suggested that OXA/TA NPs-H might have potential application in the treatment of colorectal cancer.

Combination of oncolytic adenovirus and luteolin exerts synergistic antitumor effects in colorectal cancer cells and a mouse model

In recent years, oncolytic viruses have attracted increasing interest due to their potent antitumor effects. Luteolin, a natural product, has additionally been observed to exhibit various pharmacological antitumor activities. Previously, a novel dual-targeting oncolytic adenovirus, complement decay-accelerating factor (CD55)-tumor necrosis factor ligand superfamily member 10 (TRAIL), was constructed, which exhibited significant growth inhibitory effects in various types of tumor cell. The present study investigated whether the combination of luteolin and CD55-TRAIL was able to exert a synergistic antitumor effect in colorectal carcinoma (CRC) cells. The cytotoxicity and tumor cell apoptosis mediated by combination treatment in CRC cells were detected via an MTT assay, Hoechst staining and western blotting, respectively. Tumor growth in vivo was examined in a CRC mouse xenograft model following various treatments. The results demonstrated that the addition of luteolin enhanced oncolytic adenovirus-mediated enhanced green fluorescent protein, early region 1A and TRAIL expression. The combination of CD55-TRAIL with luteolin synergistically inhibited tumor growth and promoted CRC cellular apoptosis in vitro and in vivo. Additionally, the combination of CD55-TRAIL with luteolin significantly decreased cytotoxicity in lung/bronchial normal epithelial cells, compared with single treatment. Therefore, the combination of CD55-TRAIL with luteolin may be a novel efficient therapeutic strategy for CRC in the future.

Effects of tumor microenvironments on targeted delivery of glycol chitosan nanoparticles

In cancer theranostics, the main strategy of nanoparticle-based targeted delivery system has been understood by enhanced permeability and retention (EPR) effect of macromolecules. Studies on diverse nanoparticles provide a better understanding of different EPR effects depending on their structure, physicochemical properties, and chemical modifications. Recently the tumor microenvironment has been considered as another important factor for determining tumor-targeted delivery of nanoparticles, but the correlation between EPR effects and tumor microenvironment has not yet been fully elucidated. Herein, ectopic subcutaneous tumor models presenting different tumor microenvironments were established by inoculation of SCC7, U87, HT29, PC3, and A549 cancer cell lines into athymic nude mice, respectively. In the five different types of tumor-bearing mice, tumor-targeted delivery of self-assembled glycol chitosan nanoparticles (CNPs) were comparatively evaluated to identify the correlation between the tumor microenvironments and targeted delivery of CNPs. As a result, neovascularization and extents of intratumoral extracellular matrix (ECM) were both important in determining the tumor targeted delivery of CNPs. The EPR effect was maximized in the tumors which include large extent of angiogenic blood vessels and low intratumoral ECM content. This comprehensive study provides substantial evidence that the EPR effects based tumor-targeted delivery of nanoparticles can be different depending on the tumor microenvironment in individual tumors. To overcome current limitations in clinical nanomedicine, the tumor microenvironment of the patients and EPR effects in clinical tumors should also be carefully studied.

Combination of AAV-TRAIL with miR-221-Zip Therapeutic Strategy Overcomes the Resistance to TRAIL Induced Apoptosis in Liver Cancer

TNF-related apoptosis-inducing ligand (TRAIL) possesses the capacity to induce apoptosis in a wide variety of tumor cells without affecting most normal cells. However, it has now emerged that many primary cancer cells are resistant to TRAIL monotherapy. Overcoming the intrinsic or acquired TRAIL resistance is desirable for TRAIL-mediated cancer therapy. In this study, we found that the miR-221/222 cluster was up-regulated in TRAIL-resistant liver cancer cells. Specific inhibitors of miR-221 and/or miR-222, called sponge, TuD and miR-Zip were constructed, and their ability to overcome TRAIL resistance was compared. Among them, AAV-mediated gene therapy using co-expression of TRAIL with miR-221-Zip showed the most synergistic activity in the induction of apoptosis in vitro. In vivo treatment of nude mice bearing human TRAIL-resistant liver cancer xenografts with AAV-TRAIL-miR-221-Zip also led to growth inhibition. This sensitizing effect of miR-221-Zip was associated with increased expression of PTEN, the miR-221 target, as well as with decreasing levels of Survivin. Moreover, miR-221 expression was concomitant with promotion of Survivin expression and suppression of PTEN expression. TRAIL sensitivity of cancer cells isolated from liver cancer tissues or from patients was significantly correlated with miR-221 expression. And miR-221 blood expression levels in liver cancer patients were correlated with TRAIL sensitivity, thus it had the potential to be a predictor of TRAIL sensitivity in liver cancer. These data suggested the potential of combining AAV-TRAIL with miR-221-Zip as a therapeutic intervention for liver cancer.

Preclinical study of rAAV2-sTRAIL: pharmaceutical efficacy, biodistribution and safety in animals

The recombinant sTRAIL has been in clinical trial for various human malignancies. However, the half-life time of sTRAIL is very short, which might be an important factor influencing its clinical efficacy for cancer therapy. We previously reported the recombinant adeno-associated virus (AAV)-encoding sTRAIL_95-281-mediated sTRAIL expression in vivo up to 8 months and suppressed tumor growth markedly in mouse xenografts. In the present study, we further evaluated the clinical potency for cancer gene therapy and the safety in mouse and non-human primates. The mouse models with HCT-116, NCI-H460 and BEL-7402 cancers were injected intraperitoneally with a single dose of 1.0 × 10¹¹, 1.0 × 10¹⁰ and 1.0 × 10⁹ vg of rAAV2-sTRAIL_95-281 virus, respectively. The cynomolgus monkeys were injected (i.m.) with a single dose of rAAV2-sTRAIL_95-281 of 1 × 10¹¹, 3 × 10¹¹ and 1 × 10¹² vg, corresponding to 6-, 20- and 60-fold of intended use dosage for humans, respectively. The efficacy, pharmacology and toxicity of rAAV-sTRAIL in the animals were analyzed accordingly. The tumor inhibitory rates reached 44-76%, 48-52% and 55-74% in the three tumor models, respectively, and they had no influence on mouse spontaneous activity. Administration (s.c.) of a single dose of rAAV2-sTRAIL_95-281 virus of 1.0 × 10⁹ or 1.0 × 10¹⁰ vg in mice with implanted tumor led to mainly distribution in the spleen, liver, implanted tumor, blood, injected site of muscle and bone marrow. Two weeks later, there was no rAAV2-sTRAIL_95-281 detected in blood and bone marrow, and it significantly decreased in other tissues and organs and then gradually cleared away in 4-12 weeks after administration. There was no rAAV2-sTRAIL accumulation in the animal's body and no influence on the body weights. Administration (i.v.) did not cause animal death, and no dose-related abnormal clinical symptoms were found in the mice. There were no abnormal tissue and organ found in all animals. Long-term toxicity test in cynomolgus monkeys did not cause rAAV2-sTRAIL_95-281-related toxic and side effects, except that anti-AAV and anti-sTRAIL antibodies were generated. In conclusion, these data demonstrated that administration of rAAV2-sTRAIL_95-281 in mice and in cynomolgus monkeys is safe without obvious toxic and side effects to the animals, and throw light on pharmacokinetics and safety in human clinical trials for cancer gene therapy.

Systemic delivery and activation of the TRAIL gene in lungs, with magnetic nanoparticles of chitosan controlled by an external magnetic field

Recently, functional therapies targeting a specific organ without affecting normal tissues have been designed. The use of magnetic force to reach this goal is studied in this work. Previously, we demonstrated that nanocarriers based on magnetic nanoparticles could be directed and retained in the lungs, with their gene expression under the control of a promoter activated by a magnetic field. Magnetic nanoparticles containing the TRAIL gene and chitosan were constructed using the ionic gelation method as a nanosystem for magnetofection and were characterized by microscopy, ζ-potential, and retention analysis. Magnetofection in the mouse melanoma cell line B16F10 in vitro induced TRAIL-protein expression and was associated with morphological changes indicative of apoptosis. Systemic administration of the nanosystem in the tail vein of mice with melanoma B16F10 at the lungs produced a very significant increase in apoptosis in tumoral cells that correlated with the number of melanoma tumor foci observed in the lungs. The high levels of apoptosis detected in the lungs were partially related to mouse survival. The data presented demonstrate that the magnetofection nanosystem described here efficiently induces apoptosis and growth inhibition of melanoma B16F10 in the lungs. This new approach for systemic delivery and activation of a gene based in a nanocomplex offers a potential application in magnetic gene delivery for cancer.

Adeno-associated virus (AAV) vectors in cancer gene therapy

Gene delivery vectors based on adeno-associated virus (AAV) have been utilized in a large number of gene therapy clinical trials, which have demonstrated their strong safety profile and increasingly their therapeutic efficacy for treating monogenic diseases. For cancer applications, AAV vectors have been harnessed for delivery of an extensive repertoire of transgenes to preclinical models and, more recently, clinical trials involving certain cancers. This review describes the applications of AAV vectors to cancer models and presents developments in vector engineering and payload design aimed at tailoring AAV vectors for transduction and treatment of cancer cells. We also discuss the current status of AAV clinical development in oncology and future directions for AAV in this field.

Systemically administered AAV9-sTRAIL combats invasive glioblastoma in a patient-derived orthotopic xenograft model

Adeno-associated virus (AAV) vectors expressing tumoricidal genes injected directly into brain tumors have shown some promise, however, invasive tumor cells are relatively unaffected. Systemic injection of AAV9 vectors provides widespread delivery to the brain and potentially the tumor/microenvironment. Here we assessed AAV9 for potential glioblastoma therapy using two different promoters driving the expression of the secreted anti-cancer agent sTRAIL as a transgene model; the ubiquitously active chicken β-actin (CBA) promoter and the neuron-specific enolase (NSE) promoter to restrict expression in brain. Intravenous injection of AAV9 vectors encoding a bioluminescent reporter showed similar distribution patterns, although the NSE promoter yielded 100-fold lower expression in the abdomen (liver), with the brain-to-liver expression ratio remaining the same. The main cell types targeted by the CBA promoter were astrocytes, neurons and endothelial cells, while expression by NSE promoter mostly occurred in neurons. Intravenous administration of either AAV9-CBA-sTRAIL or AAV9-NSE-sTRAIL vectors to mice bearing intracranial patient-derived glioblastoma xenografts led to a slower tumor growth and significantly increased survival, with the CBA promoter having higher efficacy. To our knowledge, this is the first report showing the potential of systemic injection of AAV9 vector encoding a therapeutic gene for the treatment of brain tumors.

Enhanced antitumor effect of combining TRAIL and MnSOD mediated by CEA-controlled oncolytic adenovirus in lung cancer

Lung cancer, especially adenocarcinoma, is one of the leading causes of death in the world. Carcinoembryonic antigen (CEA), a superb non-small-cell lung cancer marker candidate, showed a beneficial effect in cancer therapy with oncolytic adenovirus in recent studies. Cancer-targeting dual gene-virotherapy delivers two therapeutic genes, linked by a connexon, in the replication-deficient vector instead of one gene so that they can work in common. In this study, we constructed a tumor-specific oncolytic adenovirus, CD55-TRAIL-IETD-MnSOD. The virus has the fusion protein complementary DNAs for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and for manganese superoxide dismutase (MnSOD) complementary DNA linked through a 4-amino acid caspase-8 cleavage site (IETD), and uses a CEA promoter to control virus E1A express. This is the first work to use a CEA promoter-regulated oncolytic adenovirus carrying two therapeutic genes for cancer research. Its targeting and anticancer capacity was evaluated by in vitro and in vivo experiments. The results indicated that CD55-TRAIL-IETD-MnSOD caused more cell apoptosis than CD55-TRAIL or CD55-MnSOD alone, or their combination in vitro, with low cytotoxicity of normal cells. In the A549 tumor xenograft model in nude mice, data showed that CD55-TRAIL-IETD-MnSOD could effectively suppress tumor growth than single gene groups, with no histological damage in liver, spleen or kidney tissues. Thus, the CEA-regulated dual-gene oncolytic virus CD55-TRAIL-IETD-MnSOD may be a novel potential therapy for lung cancer.

Tumor necrosis factor-related apoptosis-inducing ligand induces the expression of proinflammatory cytokines in macrophages and re-educates tumor-associated macrophages to an antitumor phenotype

This study reveals that tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) induces expression of IL-1β, IL-6, and tumor necrosis factor α in macrophages, especially in tumor-associated macrophages (TAMs). TRAIL re-educates TAMs to an M1-like phenotype and induces their cytotoxicity to tumor cells. This study provides new evidence for TRAIL in immune regulation of macrophages and sheds light on TRAIL-based antitumor therapy in human patients.

Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer therapy, because it can induce apoptosis in various tumor cells but not in most normal cells. Although it is well known that TRAIL and its receptors are expressed in many types of normal cells, including immune cells, their immunological effects and regulatory mechanisms are still obscure. In the present study, we demonstrated that TRAIL affected the activity of NF-κB (nuclear factor-κB) and the expression of its downstream proinflammatory cytokines IL-1β (interleukin-1β), IL-6, and tumor necrosis factor α in macrophages. TRAIL also induced microRNA-146a (miR-146a) expression in an NF-κB–dependent manner. As a result, miR-146a was involved as a negative-feedback regulator in the down-regulation of proinflammatory cytokine expression. In addition, the suppression of histone deacetylase (HDAC) activities by trichostatin A improved miR-146a expression due to the up-regulation of the DNA-binding activity of NF-κB at the miR-146a promoter in TRAIL-induced macrophages, suggesting that histone acetylation was involved in the suppression of miR-146a expression. Further investigation revealed that the HDAC subtype HDAC1 directly regulated the expression of miR-146a in TRAIL-stimulated macrophages. Finally, the TRAIL-sensitive human non small cell lung carcinoma cell line NCI-H460 was used to elucidate the physiological significance of TRAIL with respect to tumor-associated macrophages (TAMs). We demonstrated that TRAIL re-educated TAMs to an M1-like phenotype and induced cytotoxic effects in the tumor cells. These data provide new evidence for TRAIL in the immune regulation of macrophages and may shed light on TRAIL-based antitumor therapy in human patients.

Hypericin-mediated photodynamic therapy induces apoptosis of myoloma SP2/0 cells depended on caspase activity in vitro

BACKGROUND

Photodynamic therapy (PDT) is becoming a promising therapeutic modality for hematological malignancies. Hypericin is a natural photosensitizer possessing anti-depressant, anti-virus and anti-cancer activities. The present study was designed to explore the effect and mechanism of hypericin-mediated PDT on the mouse multiple myeloma (MM) cells in vitro.

METHODS

The mouse myeloma SP2/0 cells were incubed with different concentrations of hypericin and then illuminated with different light doses. The inhibitory effect of hypericin-mediated PDT on tumor cell proliferation was assayed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method. The apoptosis related morphological changes of SP2/0 cells were observed by microscopy. The biochemical hallmarks of apoptosis such as DNA fragments, mitochondrial membrane potential changes were assessed. The expression of apoptosis related proteins were investigated by western blotting.

RESULTS

Hypericin-mediated PDT induced the proliferation inhibition and apoptosis of tumor cells in a dose dependent manner. Tumor cells showed obvious morphological changes of apoptosis and necrosis and DNA fragmentation after treated by hypericin mediated PDT (0.025 ~ 0.05 μM). The mitochondria membrane potential in SP2/0 cells was decreased significantly after incubated with the 0.025 μM and 0.5 μM hypericin (P < 0.05). The expression level of caspase-3 was decreased, while caspase activity was elevated with the increasing drug dosage. The apoptosis of SP2/0 cells was blocked by a pan-caspase inhibitor Z-VAD-FMK and caspase-3 inhibitor Ac-DEVD-CHO.

CONCLUSION

Hypericin-mediated PDT induced apoptosis mainly dependent on caspase related pathways. Hypericin-mediated PDT may be a potential and alternative therapy for MM.

Restoring TRAIL mediated signaling in ovarian cancer cells

Ovarian cancer has emerged as a multifaceted and genomically complex disease. Genetic/epigenetic mutations, suppression of tumor suppressors, overexpression of oncogenes, rewiring of intracellular signaling cascades and loss of apoptosis are some of the deeply studied mechanisms. In vitro and in vivo studies have highlighted different molecular mechanisms that regulate tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mediated apoptosis in ovarian cancer. In this review, we bring to limelight, expansion in understanding systematical characterization of ovarian cancer cells has led to the rapid development of new drugs and treatments to target negative regulators of TRAIL mediated signaling pathway. Wide ranging synthetic and natural agents have been shown to stimulate mRNA and protein expression of death receptors. This review is compartmentalized into programmed cell death protein 4, platelet-derived growth factor signaling and miRNA control of TRAIL mediated signaling to ovarian cancer. Mapatumumab and PRO95780 have been tested for efficacy against ovarian cancer. Use of high-throughput screening assays will aid in dissecting the heterogeneity of this disease and increasing a long-term survival which might be achieved by translating rapidly accumulating information obtained from molecular and cellular studies to clinic researches.

2'-hydroxyflavanone induces apoptosis of human osteosarcoma 143 B cells by activating the extrinsic TRAIL- and intrinsic mitochondria-mediated pathways

Flavanones demonstrate a propensity to antiproliferation and induce apoptosis of malignant cells. Among the 4 flavanones under study, 2'-hydroxyflavanone exhibited the greatest potency to reduce the cell viability of 143 B cells in 4 osteosarcoma cells. Flow cytometry analysis showed that 2'-hydroxyflavanone increased the hypodiploid cells in the sub-G1 phase but resulted in the reduced DNA content in the G0/G1 phase in 143 B cells. The 2'-hydroxyflavanone-induced apoptosis in 143 B cells was confirmed by 4'-6-diamidino-2-phenylindole staining and mitochondrial membrane potential (Δψm) assay. Increasing expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and death receptor 5 (DR5) were found in 2'-hydroxyflavanone-treated cells. Moreover, 2'-hydroxyflavanone increased the expressions of B-cell lymphoma-extra small, cytochrome c, and cleavage poly (ADP-ribose) polymerase but downregulated B-cell lymphoma/leukemia-2expressions in 143 B cells. Furthermore, in vivo experiments showed that 2'-hydroxyflavanone inhibited the tumor growth of 143 B cells. 2'-hydroxyflavanone induced the apoptosis of 143 B cells via the extrinsic TRAIL- and intrinsic mitochondrial-dependent pathways, indicating its potential for inducing cancer apoptosis in osteosarcoma.

Selective killing effect of oxytetracycline, propafenone and metamizole on A549 or Hela cells

OBJECTIVE

To determine the selective killing effect of oxytetracycline, propafenone and metamizole on A549 or Hela cells.

METHODS

Proliferation assay, lactate dehydrogenase (LDH) assay, apoptosis detecting, flow cytometry and western blot were performed.

RESULTS

It was found that treatment with propafenone at the concentration of 0.014 g/L or higher for 48 h could induce apoptosis in Hela cells greatly, while it was not observed in oxytetracycline and metamizole at the concentration of 0.20 g/L for 48 h. Oxytetracycline, propafenone and metamizole all displayed evident inhibitory effects on the proliferation of A549 cells. The results of LDH assay demonstrated that the drugs at the test range of concentration did not cause necrosis in the cells. Propafenone could elevate the protein level of P53 effectively (P<0.01).

CONCLUSIONS

Oxytetracycline, propafenone and metamizol (dipyrone) all displayed evident inhibitory effects on the proliferation of A549 cells. Propafenone also displayed evident inhibitory effects on the proliferation of Hela cells.

Luteolin sensitizes the antiproliferative effect of interferon α/β by activation of Janus kinase/signal transducer and activator of transcription pathway signaling through protein kinase A-mediated inhibition of protein tyrosine phosphatase SHP-2 in cancer cells

New negative regulators of interferon (IFN) signaling, preferably with tissue specificity, are needed to develop therapeutic means to enhance the efficacy of type I IFNs (IFN-α/β) and reduce their side effects. We conducted cell-based screening for IFN signaling enhancer and discovered that luteolin, a natural flavonoid, sensitized the antiproliferative effect of IFN-α in hepatoma HepG2 cells and cervical carcinoma HeLa cells. Luteolin promoted IFN-β-induced Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway activation by enhancing the phosphorylation of Jak1, Tyk2, and STAT1/2, thereby promoting STAT1 accumulation in the nucleus and endogenous IFN-α-regulated gene expression. Of interest, inhibition of phosphodiesterase (PDE) abolished the effect of IFN-β and luteolin on STAT1 phosphorylation. Luteolin also increased the cAMP-degrading activity of PDE bound with type I interferon receptor 2 (IFNAR2) and decreased the intracellular cAMP level, indicating that luteolin may act on the JAK/STAT pathway via PDE. Protein kinase A (PKA) was found to negatively regulate IFN-β-induced JAK/STAT signaling, and its inhibitory effect was counteracted by luteolin. Pull-down and immunoprecipitation assays revealed that type II PKA interacted with IFNAR2 via the receptor for activated C-kinase 1 (RACK-1), and such interaction was inhibited by luteolin. Src homology domain 2 containing tyrosine phosphatase-2 (SHP-2) was further found to mediate the inhibitory effect of PKA on the JAK/STAT pathway. These data suggest that PKA/PDE-mediated cAMP signaling, integrated by RACK-1 to IFNAR2, may negatively regulate IFN signaling through SHP-2. Inhibition of this signaling may provide a new way to sensitize the efficacy of IFN-α/β.

Level of TNF-related apoptosis-inducing-ligand and CXCL8 correlated with 2-[18F]Fluoro-2-deoxy-D-glucose uptake in anti-VEGF treated colon cancers

BACKGROUND

The changes and correlations of TRAIL (TNF-related apoptosis-inducing-ligand) and CXCL8 (IL8) prior to treatment and three months following therapy as well as the corresponding Positron emission tomography (PET/CT) (SUV(max): standardized uptake maximum values) results were evaluated.

MATERIAL AND METHODS

The measurements were taken before and after treatment for comparison purposes. The study population comprised 29 patients with Metastatic Colorectal cancer (MCRC), undergoing PET/CT scanning prior to treatment.

RESULTS

There were significant changes prior to treatment and three months later for sTRAIL (p=0.0080) and CXCL8 (p=0.0001)values. Generally, sTRAIL values were increasing during therapy, while a decrease was observed for CXCL8. Correlation analysis was applied to the data and revealed significant correlations for the SUV(max) in the primary tumor prior to treatment and CXCL8 prior to therapy (p=0.0303). Furthermore, significant correlations were observed for the SUV(max) and sTRAIL (p=0.0237) as well as CXCL8 (p=0.0002) three months after treatment initiation. CXCL8 prior to treatment was also correlated with the SUV three months after onset of treatment (p=0.0072). A significant correlation was noted for one combination of two variables, the SUV(max) in the metastases and CXCL8 prior to treatment (p=0.0175). These results are supported when we group the SUV(max) in the metastases following treatment into two groups with SUV(max) <5 and SUV(max) >5.

CONCLUSIONS

This study provides evidence that proteomics patterns of sTRAIL and CXCL8 predict tumor response und survival in MCRC patients treated with bevacizumab and within a high concordance of FDG-PET/CT findings.

A reliable and feasible qPCR strategy for titrating AAV vectors

BACKGROUND

Previous studies have revealed that traditional real-time quantitative PCR (qPCR) underestimates adeno-associated virus (AAV) titer. Because the inverted terminal repeat (ITR) exists in all AAV vectors, the only remaining element from the wild genome could form special configurations to interfere with qPCR titration. To solve this problem, a modified and universal qPCR method was tested and established.

MATERIAL AND METHODS

In this work, there was a great variation in titration of ssAAV2-EGFP (Enhanced Green Fluorescence Protein) and scAAV2-EGFP genome by traditional qPCR. For ssAAV2-EGFP, the highest titer was found by using the targeting EGFP primers and the lowest titer was measured by those targeting bovine growth hormone polyA element (pBGH) primers.

RESULTS

Experimental data were reverse for ssAAV2-EGFP and scAAV2-EGFP. Here we report an improved and universal SmaI qPCR method, based on cleaving all ITRs in AAV2 genome by SmaI with several advantages: (1) impact of all ITRs in ssAAV2 and scAAV2 was dismissed; (2) titers increased remarkably, up to 7-fold, especially for scAAV2; (3) the variation of titers was reduced when different primers were applied. A similar phenomenon was also observed in other ssAAV2 and scAAV2 products when the range of titration was at 3×107 to 7×109 V.G/µl in this study.

CONCLUSIONS

This modified qPCR strategy can increase rAAV' titer and reduce titration variance, possibly become a universal method for titrating AAV vectors.

Comparative analysis of the transduction efficiency of five adeno associated virus serotypes and VSV-G pseudotype lentiviral vector in lung cancer cells

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths in the US. Recombinant vectors based on adeno-associated virus (AAV) and lentivirus are promising delivery tools for gene therapy due to low toxicity and long term expression. The efficiency of the gene delivery system is one of the most important factors directly related to the success of gene therapy.

METHODS

We infected SCLC cell lines, SHP-77, DMS 53, NCI-H82, NCI-H69, NCI-H727, NCI-H1155, and NSCLC cell lines, NCI-H23, NCI-H661, and NCI-H460 with VSV-G pseudo-typed lentivirus or 5 AAV serotypes, AAV2/1, AAV2/2, AAV2/4, AAV2/5, and AAV2/8 expressing the CMV promoter mCherry or green fluorescent protein transgene (EGFP). The transduction efficiency was analyzed by fluorescent microscopy and flow cytometry.

RESULTS

Of all the serotypes of AAV examined, AAV2/1 was the optimal serotype in most of the lung cancer cell lines except for NCI-H69 and NCI-H82. The highest transduction rate achieved with AAV2/1 was between 30-50% at MOI 100. Compared to all AAV serotypes, lentivirus had the highest transduction efficiency of over 50% at MOI 1. Even in NCI-H69 cells resistant to all AAV serotypes, lentivirus had a 10-40% transduction rate. To date, AAV2 is the most widely-used serotype to deliver a transgene. Our results showed the transduction efficiency of AAVs tested was AAV2/1 > AA2/5 = AAV2/2> > AAV2/4 and AAV2/8.

CONCLUSIONS

This study demonstrated that VSV-G pseudotyped lentivirus and AAV2/1 can mediate expression of a transgene for lung cancer gene therapy. Overall, our results showed that lentivirus is the best candidate to deliver a transgene into lung cancer cells for treatment.

Urotensin II contributes to the formation of lung adenocarcinoma inflammatory microenvironment through the NF-κB pathway in tumor-bearing nude mice

Urotensin II (UII), a somatostatin-like cyclic peptide, was originally isolated from the fish urophysis. Our previous study showed that UII stimulates the proliferation of A549 lung adenocarcinoma cells and promotes tumor growth in a nude mouse xenograft model, suggesting that UII may contribute to the pathogenesis of lung adenocarcinoma. In this study, the underlying mechanism for UII to promote lung adenocarcinoma growth was explored by observing the effect of UII on the tumor inflammatory microenvironment in tumor-bearing nude mice. Immunohistochemical analysis showed that UII promoted the infiltration of CD68(+) tumor-associated macrophages (TAMs) in the tumor micro-environment. Enzyme-linked immunosorbent assay (ELISA) demonstrated that UII promoted the release of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-9 (MMP-9). Western blot analysis showed that UII promoted the activation of nuclear factor-κB (NF-κB). These findings suggest that the enhanced levels of IL-6, TNF-α and MMP-9 in the tumor microenvironment, which likely resulted from increased activation of NF-κB induced by UII, may be one of the important mechanisms by which UII promotes lung adenocarcinoma growth. These findings imply that antagonists of UII or urotensin II-receptor (UT-R) have potential for the prevention and treatment of lung adenocarcinoma.

Epirubicin potentiates recombinant adeno-associated virus type 2/5-mediated TRAIL expression in fibroblast-like synoviocytes and augments the antiarthritic effects of rAAV2/5-TRAIL

OBJECTIVE

Synovial cells in rheumatoid synovium display abnormal proliferation, which leads to joint destruction. TRAIL has been described as a proapoptotic factor in fibroblast-like synoviocytes (FLS). This study was undertaken to investigate the functions of rAAV2/5-TRAIL in human FLS and in arthritic mice.

METHODS

Primary human FLS were infected with rAAV2/5-TRAIL in the presence or absence of epirubicin. Transgene expression was monitored by both enzyme-linked immunosorbent assay and flow cytometry. The disease-modulating activity of epirubicin plus rAAV2/5-TRAIL was investigated in mice with collagen-induced arthritis (CIA).

RESULTS

Subtoxic doses of epirubicin potentiated rAAV2/5-mediated TRAIL expression in FLS and simultaneously enhanced the sensitivity of FLS to TRAIL. Epirubicin treatment up-regulated death receptor 4 (DR-4) and DR-5 expression and down-regulated FLIP expression, thereby enhancing the activation of procaspase 3, procaspase 8, and procaspase 9. An in vivo study showed that the combination of rAAV2/5-TRAIL gene therapy and epirubicin chemotherapy provided augmented antiarthritic effects in a mouse model of CIA. The intraarticular injection of rAAV2/5-TRAIL combined with epirubicin treatment significantly reduced the severity and incidence of CIA and joint swelling in the animals. Histologic evaluations revealed that inflammatory cell infiltration, cartilage destruction, and bone erosion were significantly reduced in the joints of the mice receiving the synthetic treatment. Results of a viral genome copy number assay indicated that epirubicin dramatically augmented the expression of rAAV2/5-TRAIL without altering its tissue distribution.

CONCLUSION

These results suggest that epirubicin enhances the antiarthritic effect of rAAV2/5-TRAIL and that combination treatment might be an important therapeutic alternative, with practical significance for rheumatoid arthritis.

Synergistic antitumor effect of TRAIL and IL-24 with complete eradication of hepatoma in the CTGVT-DG strategy

The ZD55-tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and ZD55-interleukin (IL)-24 were constructed by inserting TRAIL or IL-24 gene separately into the oncolytic adenovirus named ZD55 (with adenovirus E1B-55kD deletion). The resulting ZD55-TRAIL and ZD55-IL-24 were used in combination to treat xenograft tumors in nude mice model. The results showed that it can not only completely eliminate BEL7404 hepatoma xenograft but also have excellent antitumor effect against gaster, lung, prostate, and breast carcinomas. It was also found that ZD55-TRAIL could not only suppress the tumor growth promoting effect by ZD55-IL-24 at lower dosage, but also substantially reduce the cancer cell viability in their combined use. This is because ZD55-IL-24 and ZD55-TRAIL could mutually enhance each other's antitumor effect greatly. All these findings conspicuously showed the synergistic antitumor effect of TRAIL and IL-24, which is also the reason for the antitumor effect by the combined use of TRAIL and IL-24 in vitro and also in vivo.

Induction of proapoptotic antibodies to triple-negative breast cancer by vaccination with TRAIL death receptor DR5 DNA

TNF-related apoptosis-inducing ligand receptor 2 [TRAIL-R2 or death receptor 5 (DR5)] is expressed at elevated levels in a broad range of solid tumors to mediate apoptotic signals from TRAIL or agonist antibodies. We tested the hypothesis that DR5 DNA vaccination will induce proapoptotic antibody to trigger apoptosis of tumor cells. BALB/c mice were electrovaccinated with DNA-encoding wild-type human DR5 (phDR5) or its derivatives. Resulting immune serum or purified immune IgG induced apoptosis in triple-negative breast cancer (TNBC) cells, which were also TRAIL sensitive. The proapoptotic activity of immune serum at dilutions of 0.5-2% was comparable to that of 1-2 μg/ml of TRAIL. Apoptotic activity of immune serum was enhanced by antibody crosslinking. Apoptotic cell death induced by anti-DR5 antibody was shown by the cleavage of PARP and caspase-3. In contrast, immune serum had no effect on the proliferation of activated human T cells, which expressed low levels of DR5. In vivo, hDR5 reactive immune serum prevented growth of SUM159 TNBC cells in severe combined immune-deficient mice. DR5-specific IFN-γ-secreting T cells were also induced by DNA vaccination. Furthermore, the feasibility to overcome immune tolerance to self DR5 was shown by the induction of mouse DR5-binding antibody after electrovaccination of BALB/c mice with pmDR5ectm-Td1 encoding a fusion protein of mouse DR5 and an immunogenic fragment of tetanus toxin. These findings support DR5 as a promising vaccine target for controlling TNBC and other DR5-positive cancers.

Adeno-associated virus-mediated doxycycline-regulatable TRAIL expression suppresses growth of human breast carcinoma in nude mice

Background

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells. Numerous studies have demonstrated the potential use of recombinant soluble TRAIL as a cancer therapeutic agent. We have showed previous administration of a recombinant adeno-associated virus (rAAV) vector expressing soluble TRAIL results in an efficient suppression of human tumor growth in nude mice. In the present study, we introduced Tet-On gene expression system into the rAAV vector to control the soluble TRAIL expression and evaluate the efficiency of the system in cancer gene therapy.

Methods

Controllability of the Tet-On system was determined by luciferase activity assay, and Western blotting and enzyme-linked immunoabsorbent assay. Cell viability was determined by MTT assay. The breast cancer xenograft animal model was established and recombinant virus was administrated through tail vein injection to evaluate the tumoricidal activity.

Results

The expression of soluble TRAIL could be strictly controlled by the Tet-On system in both normal and cancer cells. Transduction of human cancer cell lines with rAAV-TRE-TRAIL&rAAV-Tet-On under the presence of inducer doxycycline resulted in a considerable cell death by apoptosis. Intravenous injection of the recombinant virus efficiently suppressed the growth of human breast carcinoma in nude mice when activated by doxycycline.

Conclusion

These data suggest that rAAV-mediated soluble TRAIL expression under the control of the Tet-On system is a promising strategy for breast cancer therapy.

Increased serum sTRAIL levels were correlated with survival in bevacizumab-treated metastatic colon cancer

BACKGROUND

Colorectal cancer is the third most common cancer and the third leading cause of cancer-related death. Bevacizumab is a humanized monoclonal antibody developed against vascular endothelial growth factor (VEGF) for the treatment of metastatic cancer. The parameters of RECIST (Response Evaluation Criteria for Solid Tumors) are not adequate to detect important treatment effects and response. Our goal was to evaluate the possibility of using sTRAIL (serum-soluble TNF-related apoptosis-inducing ligand) and VEGF as markers of treatment efficacy and prognosis in patients with metastatic colon cancer.

METHODS

sTRAIL and VEGF levels were measured by ELISA in the sera of 16 bevacizumab-treated metastatic colon cancer patients and 10 presumably healthy age-matched controls. The measurements were taken before and after treatment for comparison purposes.

RESULTS

Elevated levels of sTRAIL were found in seven out of 16 patients after bevacizumab treatment. Although these patients had a median survival time of 20.6 months, the remaining bevacizumab-treated patients who did not show an increase in sTRAIL had a median survival time of 9.4 months. As expected, serum VEGF levels were decreased in all patients who received bevacizumab therapy and showed no correlation between serum VEGF levels and patient survival (data not shown).

CONCLUSIONS

Serum sTRAIL levels might be a useful predictor of prognosis in metastatic colon cancer, in the early evaluation stages following bevacizumab treatment.

Down-regulation of DcR2 sensitizes androgen-dependent prostate cancer LNCaP cells to TRAIL-induced apoptosis

Background

Dysregulation of many apoptotic related genes and androgens are critical in the development, progression, and treatment of prostate cancer. The differential sensitivity of tumour cells to TRAIL-induced apoptosis can be mediated by the modulation of surface TRAIL receptor expression related to androgen concentration. Our previous results led to the hypothesis that downregulation of TRAIL-decoy receptor DcR2 expression following androgen deprivation would leave hormone sensitive normal prostate cells vulnerable to the cell death signal generated by TRAIL via its pro-apoptotic receptors. We tested this hypothesis under pathological conditions by exploring the regulation of TRAIL-induced apoptosis related to their death and decoy receptor expression, as also to hormonal concentrations in androgen-sensitive human prostate cancer, LNCaP, cells.

Results

In contrast to androgen-insensitive PC3 cells, decoy (DcR2) and death (DR5) receptor protein expression was correlated with hormone concentrations and TRAIL-induced apoptosis in LNCaP cells. Silencing of androgen-sensitive DcR2 protein expression by siRNA led to a significant increase in TRAIL-mediated apoptosis related to androgen concentration in LNCaP cells.

Conclusions

The data support the hypothesis that hormone modulation of DcR2 expression regulates TRAIL-induced apoptosis in LNCaP cells, giving insight into cell death induction in apoptosis-resistant hormone-sensitive tumour cells from prostate cancer. TRAIL action and DcR2 expression modulation are potentially of clinical value in advanced tumour treatment.

Gene-viro-therapy targeting liver cancer by a dual-regulated oncolytic adenoviral vector harboring IL-24 and TRAIL

Cancer-targeting gene-viro-therapy is a promising cancer therapeutic strategy that strengthens the antitumor effect of oncolytic viruses by expressing an inserted foreign antitumor gene. To achieve liver cancer targeting and to improve the safety of the ZD55 vector (a widely-used E1B55KD gene-deleted oncolytic adenoviral vector (OV), we previously constructed), we designed a novel OV named Ad·AFP·D55 that selectively replicates in hepatocellular carcinoma (HCC) cells by replacing the E1A promoter with the liver-cancer specific α-Fetoprotein (AFP) promoter based on the ZD55 vector. We found that the oncolytic adenoviruses Ad·AFP·D55-IL-24 and Ad·AFP·D55-TRAIL express tumor-suppressor gene interleukin-24 (IL-24) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), respectively, significantly suppressed the HCC cell growth in vitro by inducing apoptosis by the caspase-8 and mitochondria-dependent caspase-9 signaling pathways. Furthermore, the combined treatment of Ad·AFP·D55-IL-24 and Ad·AFP·D55-TRAIL showed strong antitumor effects in vivo by significantly inhibiting the tumor growth in HCC HuH-7 cell xenograft mice, and markedly increasing animal survival rate. Therefore, this novel HCC cell-targeting OV carrying tumor-suppressor genes may provide a promising approach for liver cancer gene therapy.

Potent antitumour activity of the combination of HSV-TK and endostatin armed oncolytic adeno-associated virus for bladder cancer in vitro and in vivo

BACKGROUND

Gene therapy may offer a new tool for the treatment of bladder cancer. Previously, we have shown a significant antitumour effect in bladder cancer xenografts in a nude mouse model using intratumoural herpes simple virus thymidine (HSV-TK) and Endostatin gene therapy.

OBJECTIVES

Given the high vascularity of human bladder cancer and the ability of HSV-TK or Endostatin monotherapy to eradicate the tumours, we decided to test a novel combination of cytotoxicity and antiangiogenisis gene therapy using intratumourally delivered HSV-TK and Endostatin adeno-associated viruses (AAVs).

METHODS

We constructed plasmid AAV-TK-IRES-Endostatin (pAAV-TIE) and packaged the AAV particles contain gene fragments of HSV-TK and Endostatin. The function of HSV-TK and Endostatin was evaluated separately in vitro via T24 bladder tumour cells and human umbilical vein endothelial (HUVEC) cells. The combination anticancer effect of recombinant AAV-TIE (rAAV-TIE) was measured in vivo while rAAV-HSV-TK and rAAV-Endostatin as control groups.

RESULTS

In vitro, rAAV-TIE was found to induce a significant increase in apoptosis in HUVEC cells equally as rAAV-Endostatin and confirmed that the inhibition of endothelial cells mediated by rAAV-TIE was associated with the apoptotic process. rAAV-TIE was found to induce a significant increase in apoptosis in T24 cells equally as rAAV-HSV-TK and confirmed that the inhibition of T24 cells mediated by rAAV-TIE was associated with the apoptotic process too. In vivo, our results showed that the tumours in mice injected with the rAAV-TIE not only took significantly longer to emerge but also that their growth, once established, was significant slower than that of tumours grown, compared with single HSV-TK or Endostatin treated animals.

CONCLUSIONS

We concluded that the inhibition of angiogenesis using Endostatin gene transfer, together with the cytotoxicity HSV-TK gene therapy, resulted in a significant antitumour effect compared to the single gene based therapy in BTCC. The results warrant further development of the combination gene therapy, and suggest that this approach, directed towards systemic efficiency, could be used as an additional treatment for human BTCC.

2A peptide-based, lentivirus-mediated anti-death receptor 5 chimeric antibody expression prevents tumor growth in nude mice

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, induces tumor cell death via death receptors on target cells, without adverse effects on most normal cells. Its receptors are therefore an attractive target for antibody-mediated tumor therapy. Here, we report the creation of a lentivirus vector constructed by linking the heavy chain and the light chain of the antibody with a 2A/furin self-processing peptide in a single open reading frame that expresses a novel chimeric antibody (named as zaptuximab) with tumoricidal activity, which is consisted of the variable region of a mouse anti-human DR5 monoclonal antibody, AD5-10, and the constant region of human immunoglobulin G1. Lentivirus-expressed zaptuximab bound specifically to its antigen, DR5, and exhibited significant apoptosis-inducing activity in various tumor cell lines. The packaged recombinant virus lenti-HF2AL showed strong apoptosis-inducing activity in vitro. Meanwhile, inoculated subcutaneous human colon HCT116 tumor formation in nude mice were inhibited significantly. Moreover, there was a synergistic effect of mitomycin C (MMC) on the observed tumoricidal efficacy, prolonging the life span of nude mice with orthotopic human lung tumor cancers. These data suggest that lentivirus-mediated, 2A peptide-based anti-DR5 chimeric antibody expression may have clinical utility as an anticancer treatment and may represent a rational adjuvant therapy in combination with chemotherapy.

NK-1 as a melanoma target

INTRODUCTION

Melanoma expresses both neurokinin-1 (NK-1) receptors and substance P (SP). After binding to the NK-1 receptor, SP induces tumor cell proliferation in melanoma cells, whereas after binding to the same NK-1 receptor, antagonists inhibit melanoma cell proliferation and cause tumor cell death by apoptosis. Thus, the NK-1 receptor could be a new and promising target in melanoma therapy.

AREAS COVERED

This review provides an overview of the underlying mechanism of action of the SP/NK-1 receptor system, and NK-1 receptor antagonists in human melanoma, over the last 7 years.

EXPERT OPINION

In stages III - IV, no effective treatment exists for melanoma and hence there is an urgent need to improve therapy in melanoma patients. The NK-1 receptor is a promising new target in human melanoma treatment, since preclinical assays (most of them in vitro assays) have reported that NK-1 receptor antagonists exert an antitumor action against melanoma. The NK-1 receptor antagonist aprepitant is used in clinical practice and exerts an antitumor action against human melanoma in vitro. In the future, such antitumor action should be tested in human clinical trials. This should be faster compared with less investigated NK-1 receptor antagonists, because a great part of the required safety and characterization studies for aprepitant have already been carried out.

Advances in Viral Vector-Based TRAIL Gene Therapy for Cancer

Numerous biologic approaches are being investigated as anti-cancer therapies in an attempt to induce tumor regression while circumventing the toxic side effects associated with standard chemo- or radiotherapies. Among these, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown particular promise in pre-clinical and early clinical trials, due to its preferential ability to induce apoptotic cell death in cancer cells and its minimal toxicity. One limitation of TRAIL use is the fact that many tumor types display an inherent resistance to TRAIL-induced apoptosis. To circumvent this problem, researchers have explored a number of strategies to optimize TRAIL delivery and to improve its efficacy via co-administration with other anti-cancer agents. In this review, we will focus on TRAIL-based gene therapy approaches for the treatment of malignancies. We will discuss the main viral vectors that are being used for TRAIL gene therapy and the strategies that are currently being attempted to improve the efficacy of TRAIL as an anti-cancer therapeutic.

Synergistic antitumor effect of AAV-mediated TRAIL expression combined with cisplatin on head and neck squamous cell carcinoma

Background

Adeno-associated virus-2 (AAV-2)-mediated gene therapy is quite suitable for local or regional application in head and neck cancer squamous cell carcinoma (HNSCC). However, its low transduction efficiency has limited its further development as a therapeutic agent. DNA damaging agents have been shown to enhance AAV-mediated transgene expression. Cisplatin, one of the most effective chemotherapeutic agents, has been recognized to cause cancer cell death by apoptosis with a severe toxicity. This study aims to evaluate the role of cisplatin in AAV-mediated tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression and the effect on HNSCC both in vitro and in vivo.

Methods

Five human HNSCC cell lines were treated with recombinant soluble TRAIL (rsTRAIL) and infected with AAV/TRAIL to estimate the sensitivity of the cancer cells to TRAIL-induced cytotoxicity. KB cells were infected with AAV/EGFP with or without cisplatin pretreatment to evaluate the effect of cisplatin on AAV-mediated gene expression. TRAIL expression was detected by ELISA and Western blot. Cytotoxicity was measured by MTT assay and Western blot analysis for caspase-3 and -8 activations. Following the in vitro experiments, TRAIL expression and its tumoricidal activity were analyzed in nude mice with subcutaneous xenografts of HNSCC.

Results

HNSCC cell lines showed different sensitivities to rsTRAIL, and KB cells possessed both highest transduction efficacy of AAV and sensitivity to TRAIL among five cell lines. Preincubation of KB cells with subtherapeutic dosage of cisplatin significantly augmented AAV-mediated transgene expression in a heparin sulfate proteoglycan (HSPG)-dependent manner. Furthermore, cisplatin enhanced the killing efficacy of AAV/TRAIL by 3-fold on KB cell line. The AAV mediated TRAIL expression was observed in the xenografted tumors and significantly enhanced by cisplatin. AAV/TRAIL suppressed the tumors growth and cisplatin augmented the tumoricidal activity by two-fold. Furthermore, Combination treatment reduced cisplatin-caused body weight loss in nude mice.

Conclusion

The combination of AAV-mediated TRAIL gene expression and cisplatin had synergistic therapeutic effects on head and neck cancers and reduced the potential toxicity of cisplatin. These findings suggest that the combination of AAV/TRAIL and cisplatin may be a promising strategy for HNSCC therapy.