DcR2 (TRAIL-R4) siRNA and adenovirus delivery of TRAIL (Ad5hTRAIL) break down in vitro tumorigenic potential of prostate carcinoma cells

Current Update on Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine Development with a Special Emphasis on Gene Therapy Viral Vector Design and Construction for Vaccination

Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease (COVID-19) caused by the novel coronavirus SARS-coronavirus 2 (CoV-2). To combat the devastating spread of SARS-CoV-2, extraordinary efforts from numerous laboratories have focused on the development of effective and safe vaccines. Traditional live-attenuated or inactivated viral vaccines are not recommended for immunocompromised patients as the attenuated virus can still cause disease via phenotypic or genotypic reversion. Subunit vaccines require repeated dosing and adjuvant use to be effective, and DNA vaccines exhibit lower immune responses. mRNA vaccines can be highly unstable under physiological conditions. On the contrary, naturally antigenic viral vectors with well-characterized structure and safety profile serve as among the most effective gene carriers to provoke immune response via heterologous gene transfer. Viral vector-based vaccines induce both an effective cellular immune response and a humoral immune response owing to their natural adjuvant properties via transduction of immune cells. Consequently, viral vectored vaccines carrying the SARS-CoV-2 spike protein have recently been generated and successfully used to activate cytotoxic T cells and develop a neutralizing antibody response. Recent progress in SARS-CoV-2 vaccines, with an emphasis on gene therapy viral vector-based vaccine development, is discussed in this review.

TRAIL therapy and prospective developments for cancer treatment

Tumor Necrosis Factor (TNF) Related Apoptosis-Inducing Ligand (TRAIL), an immune cytokine of TNF-family, has received much attention in late 1990s as a potential cancer therapeutics due to its selective ability to induce apoptosis in cancer cells. TRAIL binds to cell surface death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5) and facilitates formation of death-inducing signaling complex (DISC), eventually activating the p53-independent apoptotic cascade. This unique mechanism makes the TRAIL a potential anticancer therapeutic especially for p53-mutated tumors. However, recombinant human TRAIL protein (rhTRAIL) and TRAIL-R agonist monoclonal antibodies (mAb) failed to exert robust anticancer activities due to inherent and/or acquired resistance, poor pharmacokinetics and weak potencies for apoptosis induction. To get TRAIL back on track as a cancer therapeutic, multiple strategies including protein modification, combinatorial approach and TRAIL gene therapy are being extensively explored. These strategies aim to enhance the half-life and bioavailability of TRAIL and synergize with TRAIL action ultimately sensitizing the resistant and non-responsive cells. We summarize emerging strategies for enhanced TRAIL therapy in this review and cover a wide range of recent technologies that will provide impetus to rejuvenate the TRAIL therapeutics in the clinical realm.

Synthesis of ZnO nanoparticles using leaf extract of Tectona grandis (L.) and their anti-bacterial, anti-arthritic, anti-oxidant and in vitro cytotoxicity activities

The novelty of this present work is the investigation of the anti-bacterial, anti-arthritic, anti-oxidant andin vitrocytotoxicity activities of green synthesized Zinc Oxide Nanoparticles (ZnO NPs) using leaf aqueous extract ofTectona grandis(L.).

Analysis of TNF-related apoptosis-inducing ligand and receptors and implications in thymus biology and myasthenia gravis

Myasthenia Gravis is an autoantibody-mediated, neuromuscular junction disease, and is usually associated with thymic abnormalities presented as thymic tumors (~10%) or hyperplastic thymus (~65%). The exact role of thymus in Myasthenia Gravis development is not clear, yet many patients benefit from thymectomy. The apoptotic ligand TNF-Related Apoptosis-Inducing Ligand is thought to be involved in the regulation of thymocyte counts, although conflicting results are reported. We investigated differential expression profiles of TNF-Related Apoptosis-Inducing Ligand and its transmembrane receptors, Nuclear Factor-kB activation status, and apoptotic cell counts in healthy thymic tissue and pathological thymus from Myasthenia Gravis patients. All tissues expressed TNF-Related Apoptosis-Inducing Ligand and its receptors, with hyperplastic tissue having the highest expression levels of death receptors DR4 and DR5. No detectable Nuclear Factor-kB activation, at least via the canonical Protein Kinase A-mediated p65 Ser276 phosphorylation, was evident in any of the tissues studied. Apoptotic cell counts were higher in MG-associated tissue compared to the normal thymus. Possible use of the TNF-Related Apoptosis-Inducing Ligand within the concept of an apoptotic ligand-mediated medical thymectomy in thymoma- or thymic hyperplasia-associated Myasthenia Gravis is also discussed.

Non-viral nucleic acid containing nanoparticles as cancer therapeutics

INTRODUCTION

The delivery of nucleic acids such as DNA and short interfering RNA (siRNA) is promising for the treatment of many diseases, including cancer, by enabling novel biological mechanisms of action. Non-viral nanoparticles are a promising class of nucleic acid carriers that can be designed to be safer and more versatile than traditional viral vectors.

AREAS COVERED

In this review, recent advances in the intracellular delivery of DNA and siRNA are described with a focus on non-viral nanoparticle-based delivery methods. Material properties that have enabled successful delivery are discussed as well as applications that have directly been applied to cancer therapy. Strategies to co-deliver different nucleic acids are highlighted, as are novel targets for nucleic acid co-delivery.

EXPERT OPINION

The treatment of complex genetically-based diseases such as cancer can be enabled by safe and effective intracellular delivery of multiple nucleic acids. Non-viral nanoparticles can be fabricated to deliver multiple nucleic acids to the same cell simultaneously to prevent tumor cells from easily compensating for the knockdown or overexpression of one genetic target. The continued innovation of new therapeutic modalities and non-viral nanotechnologies to provide target-specific and personalized forms of gene therapy hold promise for genetic medicine to treat diseases like cancer in the clinic.

Optimization Studies on Prokaryotic Cell Expression of the Human Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)

The aim of the study was to optimize the in vitro induction and expression of the human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and also study the processes of its denaturation, renaturation, and purification. The pGEX-6P-1/TRAIL114-281 plasmid was induced by isopropyl-β-D-1-thiogalactopyranoside (IPTG) in Escherichia coli BL21 (DE3), and the expressed target protein was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein expressed in the form of inclusion body was first denaturalized and then renaturalized by dilution and dialysis technique. GST-rTRAIL114-281 fusion protein was purified by Glutathione-Superflow Resin affinity chromatography and confirmed by Western blot. The molecular weight of GST-rTRAIL expressed in E. coli BL21 (DE3) was approximately 40 kDa. GST-rTRAIL was mainly expressed in the form of inclusion bodies. An optimum expression was induced by IPTG at a concentration of 0.2 mM for 8 h at 37 °C. Glutathione-Superflow Resin affinity chromatography yielded the purified GST-rTRAIL protein which was confirmed by Western blot using anti-GST mouse monoclonal antibody. The optimum prokaryotic cell expression of the human GST-rTRAIL was obtained by 0.2 mM IPTG induction for 8 h at 37 °C. The denatured inclusion body protein can be refolded by dilution and dialysis and purified by Glutathione-Superflow Resin affinity chromatography.

MiRNA regulation of TRAIL expression exerts selective cytotoxicity to prostate carcinoma cells

Prostate carcinoma is the most common cancer for men and among the leading cancer-related causes. Many evidences have shown that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) potently induces apoptosis in cancer cells, and thus, is a promising biologic agent for prostate carcinoma therapy. However, TRAIL expression mediated by the current vectors lacks tumor specificity, thereby exerting cytotoxicity to normal cells. To solve this problem, we inserted miRNA response elements (MREs), miR-143 and miR-145, expression levels of which were reduced in prostate carcinoma, as well as that of miR-122, which is specifically expressed in hepatic cells, into adenoviral vectors to control TRAIL expression (Ad-TRAIL-M3). qPCR data confirmed that miR-143, miR-145, and miR-122 levels were all decreased in prostate carcinoma cell lines and prostate cancer samples from patients. Luciferase assays showed that MREs-regulated luciferase expression was potently suppressed in normal cells, but not in prostate cancer cells. Ad-TRAIL-M3, which expresses TRAIL in a MREs-regulated manner, produced high level of TRAIL and suppressed the survival of prostate cancer cells by inducing apoptosis, while Ad-TRAIL-M3 had no TRAIL expression in normal cells and thus exerted no cytotoxicity to them. The studies on PC-3 tumor xenograft in mice further confirmed that Ad-TRAIL-M3 was able to inhibit the growth of tumors and possessed high biosafety. In conclusion, we successfully generated an adenoviral vector that expresses TRAIL in miRNA-regulated mechanism. This miRNA-based gene therapy may be promising for prostate carcinoma treatment.

Death receptors as targets in cancer

Anti-tumour therapies based on the use pro-apoptotic receptor agonists, including TNF-related apoptosis-inducing ligand (TRAIL) or monoclonal antibodies targeting TRAIL-R1 or TRAIL-R2, have been disappointing so far, despite clear evidence of clinical activity and lack of adverse events for the vast majority of these compounds, whether combined or not with conventional or targeted anti-cancer therapies. This brief review aims at discussing the possible reasons for the lack of apparent success of these therapeutic approaches and at providing hints in order to rationally design optimal protocols based on our current understanding of TRAIL signalling regulation or resistance for future clinical trials.

LINKED ARTICLES

This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.

PARP-1 regulates resistance of pancreatic cancer to TRAIL therapy

PURPOSE

Activating extrinsic apoptotic pathways targeting death receptors (DR) using agonistic antibodies or TNF-related apoptosis-inducing ligand (TRAIL) is promising for cancer therapy. However, most pancreatic cancers are resistant to TRAIL therapy. The present studies aimed to identify combination therapies that enhance the efficacy of TRAIL therapy and to investigate the underlying mechanisms.

EXPERIMENTAL DESIGN

A xenograft model in nude mice was used to determine pancreatic cancer tumorigenesis and therapeutic efficacy of TRA-8, a monoclonal agonistic antibody for DR5. Pancreatic cancer cells were used to characterize mechanisms underlying PARP-1 regulation of TRA-8-induced apoptosis in vitro.

RESULTS

PARP-1 was found highly expressed in the TRA-8-resistant PANC-1 and Suit-2 cells, compared with TRA-8-sensitive BxPc-3 and MiaPaca-2. Inhibition of PARP-1 with a pharmacologic inhibitor sensitized PANC-1 and Suit2 cells to TRA-8-induced apoptosis in a dose-dependent manner. Furthermore, siRNAs specifically knocking down PARP-1 markedly enhanced TRA-8-induced apoptosis in vitro and augmented the efficacy of TRA-8 therapy on tumorigenesis in vivo. PARP-1 knockdown increased TRA-8-induced activation of caspase-8 in the death-induced signaling complex (DISC). Immunoprecipitation with DR5 antibody identified the recruitment of PARP-1 and PARP-1-mediated protein poly-ADP-ribosylation (pADPr) modification in the DR5-associated DISC. Further characterization revealed that PARP-1-mediated pADPr modification of caspase-8 inhibited caspase-8 activation, which may contribute to its function in regulating TRA-8 resistance.

CONCLUSIONS

Our studies provide molecular insights into a novel function of PARP-1 in regulating the extrinsic apoptosis machinery and also support interventions combining PARP-1 inhibitors with DR agonists for pancreatic cancer therapy.

Resistance to TRAIL in non-transformed cells is due to multiple redundant pathways

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a cytokine and a selective inducer of apoptosis in a range of tumour cells, but not in normal, untransformed cells. A large number of chemotherapeutics as well as biological agents are being tested for their potential to sensitise resistant tumour cells to TRAIL as a means to broaden the range of tumours treatable with TRAIL. However, because of the incomplete understanding of the mechanism(s) underlying TRAIL resistance in non-malignant cells, it is unpredictable whether the effect of these sensitisers will be restricted to tumour cells or they would also sensitise non-transformed cells causing unwanted toxicity. In this study, we carried out a systematic analysis of the mechanisms driving TRAIL resistance in non-transformed cells. We found that cellular FLICE-like inhibitory protein, anti-apoptotic B-cell lymphoma 2 proteins, and X-linked inhibitor of apoptosis protein were independently able to provide resistance to TRAIL. Deficiency of only one of these proteins was not sufficient to elicit TRAIL sensitivity, demonstrating that in non-transformed cells multiple pathways control TRAIL resistance and they act in a redundant manner. This is contrary to the resistance mechanisms found in tumour cell types, many of them tend to rely on a single mechanism of resistance. Supporting this notion we found that 76% of TRAIL-resistant cell lines (13 out of 17) expressed only one of the above-identified anti-apoptotic proteins at a high level (≥1.2-fold higher than the mean expression across all cell lines). Furthermore, inhibition or knockdown of the single overexpressed protein in these tumour cells was sufficient to trigger TRAIL sensitivity. Therefore, the redundancy in resistance pathways in non-transformed cells may offer a safe therapeutic window for TRAIL-based combination therapies where selective sensitisation of the tumour to TRAIL can be achieved by targeting the single non-redundant resistance pathway.

Role of TNF-related apoptosis-inducing ligand (TRAIL) in the pathogenesis of varicocele-induced testicular dysfunction

The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups: control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean±s.d. and were analyzed using computer software. The Kruskal-Wallis and Dunn's multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups (P=0.0031). The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups (P<0.0001). Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.

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.

Tracing of islet graft survival by way of in vivo fluorescence imaging

BACKGROUND

To increase the success rate in xenogeneic islet transplantation, proper assessment of graft mass is required following transplantation. For this reason, we aimed to develop a suitable fluorescence imaging system to monitor islet xenograft survival in diabetic mice.

METHODS

Adenovirus vector encoding enhanced green fluorescent protein-transduced rat pancreatic islets were transplanted under the renal capsule of streptozotocin-induced diabetic mice and the fluorescence signal was quantified over time using a cooled charge-coupled device. Non-fasting blood glucose levels were recorded during the same period. Insulin release from transduced and control islets was detected via enzyme-linked immunosorbent assay.

RESULTS

Adenovirus vector encoding enhanced green fluorescent protein infection did not alter the function or survival of pancreatic islets post transduction. A direct correlation was found between the number of islets (250-750) transplanted under the kidney capsule and the blood glucose recovery.

CONCLUSIONS

Fluorescence imaging appears to be a useful tool for quantitative assessment of islet cell viability post transplantation and could permit earlier detection of graft rejection.

Sensitization of human bladder tumor cells to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis with a small molecule IAP antagonist

Urothelial carcinoma of the bladder accounts for approximately 5% of all cancer deaths in humans. The large majority of bladder tumors are non-muscle invasive at diagnosis, but even after local surgical therapy there is a high rate of local tumor recurrence and progression. Current treatments extend time to recurrence but do not significantly alter disease survival. The objective of the present study was to investigate the tumoricidal potential of combining the apoptosis-inducing protein TNF-related apoptosis-inducing ligand (TRAIL) with a small molecule inhibitor of apoptosis proteins (IAP) antagonist to interfere with intracellular regulators of apoptosis in human bladder tumor cells. Our results demonstrate that the IAP antagonist Compound A exhibits high binding affinity to the XIAP BIR3 domain. When Compound A was used at nontoxic concentrations in combination with TRAIL, there was a significant increase in the sensitivity of TRAIL-sensitive and TRAIL-resistant bladder tumor lines to TRAIL-mediated apoptosis. In addition, modulation of TRAIL sensitivity in the TRAIL-resistant bladder tumor cell line T24 with Compound A was reciprocated by XIAP small interfering RNA-mediated suppression of XIAP expression, suggesting the importance of XIAP-mediated resistance to TRAIL in these cells. These results suggest the potential of combining Compound A with TRAIL as an alternative therapy for bladder cancer.

Screening siRNAs targeting a novel gene (HA117) and the development of a derivative recombinant adenovirus delivery system

A novel gene, HA117, was discovered in our previous work. Using the pSOS-HUS vector method which we designed at previous study, we screened for small interfering RNAs (siRNAs) that targeted HA117. The pSOS-HUS siRNA screening results were verified and a delivery system was developed that contained a recombinant adenovirus carrying DNA templates for the transcription of the HA117 siRNAs. Of five pairs of DNA templates, siRNA transcribed from HAi5 produced the strongest effect against HA117. A recombinant adenovirus containing HAi5 (Ad-HAi5) was successfully constructed and evaluated. This work has laid the foundation for further study of HA117 gene function using RNA interference technology and has showed the pSOS-HUS vector method was successfully utilized as a rapid and effective screen of siRNAs for a target gene.

Construction, screening and evaluation of a derivative recombinant adenovirus for the optimal siRNA targeting of a novel gene (HA117)

At this study, we screened for an optimal siRNA to target a novel gene named HA117 and constructed and evaluated a recombinant adenovirus carrying the DNA template for the transcription of the optimal HA117 siRNA to examine the function of HA117 and its possible mechanism of action in CW-2 cell lines. An HAi5-carrying recombinant adenovirus (Ad-HAi5) was successfully constructed and evaluated. The results show that, among five pairs of DNA templates, siRNA transcribed from HAi5 gave the strongest interference with the novel gene HA117. The expression of the exogenous HA117 gene increased drug resistance in CW-2 cells. We hypothesized that this action may be a result of HA117 through inhibiting apoptosis in CW-2 cells.

Chemotherapy overcomes TRAIL-R4-mediated TRAIL resistance at the DISC level

TNF-related apoptosis-inducing ligand or Apo2L (Apo2L/TRAIL) is a promising anti-cancer drug owing to its ability to trigger apoptosis by binding to TRAIL-R1 or TRAIL-R2, two membrane-bound receptors that are often expressed by tumor cells. TRAIL can also bind non-functional receptors such as TRAIL-R4, but controversies still exist regarding their potential to inhibit TRAIL-induced apoptosis. We show here that TRAIL-R4, expressed either endogenously or ectopically, inhibits TRAIL-induced apoptosis. Interestingly, the combination of chemotherapeutic drugs with TRAIL restores tumor cell sensitivity to apoptosis in TRAIL-R4-expressing cells. This sensitization, which mainly occurs at the death-inducing signaling complex (DISC) level, through enhanced caspase-8 recruitment and activation, is compromised by c-FLIP expression and is independent of the mitochondria. Importantly, TRAIL-R4 expression prevents TRAIL-induced tumor regression in nude mice, but tumor regression induced by TRAIL can be restored with chemotherapy. Our results clearly support a negative regulatory function for TRAIL-R4 in controlling TRAIL signaling, and unveil the ability of TRAIL-R4 to cooperate with c-FLIP to inhibit TRAIL-induced cell death.

Clinical significance of TRAIL and TRAIL receptors in patients with head and neck cancer

BACKGROUND

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a death ligand currently under clinical trials for cancer. The molecular profile of TRAIL and TRAIL receptors has not yet been mapped for patients with laryngeal squamous cell carcinoma (SCC) or patients with oral cavity squamous cell carcinoma (OCSCC).

METHODS

Paraffin-embedded tissues from 60 patients with laryngeal SCC and 14 patients with OCSCC were retrospectively analyzed using immunohistochemistry.

RESULTS

An increase in decoy-R1 (DcR1) but a decrease in decoy-R2 (DcR2) expression were observed in patients with laryngeal SCC and in patients with OCSCC compared with control individuals with benign lesions. Clinical and pathologic grading revealed distinctive TRAIL and TRAIL receptor profiles in patients with squamous cell carcinoma of the head and neck (SCCHN).

CONCLUSIONS

TRAIL and a TRAIL receptor expression profile might be useful to follow-up disease progression by virtue of its connection with clinical staging and pathologic grading in patients with laryngeal SCC.

NF-κB targeting by way of IKK inhibition sensitizes lung cancer cells to adenovirus delivery of TRAIL

Background

Lung cancer causes the highest rate of cancer-related deaths both in men and women. As many current treatment modalities are inadequate in increasing patient survival, new therapeutic strategies are required. TNF-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in tumor cells but not in normal cells, prompting its current evaluation in a number of clinical trials. The successful therapeutic employment of TRAIL is restricted by the fact that many tumor cells are resistant to TRAIL. The goal of the present study was to test a novel combinatorial gene therapy modality involving adenoviral delivery of TRAIL (Ad5hTRAIL) and IKK inhibition (AdIKKβKA) to overcome TRAIL resistance in lung cancer cells.

Methods

Fluorescent microscopy and flow cytometry were used to detect optimum doses of adenovirus vectors to transduce lung cancer cells. Cell viability was assessed via a live/dead cell viability assay. Luciferase assays were employed to monitor cellular NF-κB activity. Apoptosis was confirmed using Annexin V binding.

Results

Neither Ad5hTRAIL nor AdIKKβKA infection alone induced apoptosis in A549 lung cancer cells, but the combined use of Ad5hTRAIL and AdIKKβKA significantly increased the amount of A549 apoptosis. Luciferase assays demonstrated that both endogenous and TRAIL-induced NF-κB activity was down-regulated by AdIKKβKA expression.

Conclusions

Combination treatment with Ad5hTRAIL and AdIKKβKA induced significant apoptosis of TRAIL-resistant A549 cells, suggesting that dual gene therapy strategy involving exogenous TRAIL gene expression with concurrent IKK inhibition may be a promising novel gene therapy modality to treat lung cancer.

TRAIL death receptor-4, decoy receptor-1 and decoy receptor-2 expression on CD8+ T cells correlate with the disease severity in patients with rheumatoid arthritis

Background

Rheumatoid Arthritis (RA) is a chronic autoimmune inflammatory disorder. Although the pathogenesis of disease is unclear, it is well known that T cells play a major role in both development and perpetuation of RA through activating macrophages and B cells. Since the lack of TNF-Related Apoptosis Inducing Ligand (TRAIL) expression resulted in defective thymocyte apoptosis leading to an autoimmune disease, we explored evidence for alterations in TRAIL/TRAIL receptor expression on peripheral T lymphocytes in the molecular mechanism of RA development.

Methods

The expression of TRAIL/TRAIL receptors on T cells in 20 RA patients and 12 control individuals were analyzed using flow cytometry. The correlation of TRAIL and its receptor expression profile was compared with clinical RA parameters (RA activity scored as per DAS28) using Spearman Rho Analysis.

Results

While no change was detected in the ratio of CD4⁺ to CD8⁺ T cells between controls and RA patient groups, upregulation of TRAIL and its receptors (both death and decoy) was detected on both CD4⁺ and CD8⁺ T cells in RA patients compared to control individuals. Death Receptor-4 (DR4) and the decoy receptors DcR1 and DcR2 on CD8⁺ T cells, but not on CD4⁺ T cells, were positively correlated with patients' DAS scores.

Conclusions

Our data suggest that TRAIL/TRAIL receptor expression profiles on T cells might be important in revelation of RA pathogenesis.

TNF-related apoptosis-inducing ligand (TRAIL): a new path to anti-cancer therapies

Since its discovery in 1995, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of the tumor necrosis factor super family, has been under intense focus because of its remarkable ability to induce apoptosis in malignant human cells while leaving normal cells unscathed. Consequently, activation of the apoptotic signaling pathway from the death-inducing TRAIL receptors provides an attractive, biologically-targeted approach to cancer therapy. A great deal of research has focused on deciphering the TRAIL receptor signaling cascade and intracellular regulation of this pathway, as many human tumor cells possess mechanisms of resistance to TRAIL-induced apoptosis. This review focuses on the current state of knowledge regarding TRAIL signaling and resistance, the preclinical development of therapies targeted at TRAIL receptors and modulators of the pathway, and the results of clinical trials for cancer treatment that have emerged from this base of knowledge. TRAIL-based approaches to cancer therapy vary from systemic administration of recombinant, soluble TRAIL protein with or without the combination of traditional chemotherapy, radiation or novel anti-cancer agents to agonistic monoclonal antibodies directed against functional TRAIL receptors to TRAIL gene transfer therapy. A better understanding of TRAIL resistance mechanisms may allow for the development of more effective therapies that exploit this cell-mediated pathway to apoptosis.

Inhibition of tumor growth and induction of apoptosis in prostate cancer cell lines by overexpression of tissue inhibitor of matrix metalloproteinase-3

The destruction of extracellular matrix by matrix metalloproteinases is a key event in cancer progression. The tissue inhibitors of metalloproteinases can restrain tumor growth by inhibiting these enzymes. We sought to determine whether overexpression of tissue inhibitor of metalloproteinase-3 (TIMP-3) could suppress the malignant phenotype of human prostate cancer cell line PC-3M. Stable overexpression of TIMP-3 inhibited cell proliferation significantly by MTT assay. Both early and late apoptosis were observed in TIMP-3 overexpressing cells, and flow cytometry analysis showed S-phase blocking of the cell cycle. Monolayer invasion assay and transwell invasion assay showed significantly decreased invasive potential in TIMP-3 overexpressing cells compared with control cells. Cell adhesion and motility were also lower after TIMP-3 was overexpressed. In vivo, cells stably overexpressing TIMP-3 completely lost the ability to form tumors after injection into nude mice. Transfection of TIMP-3 into established tumors by electroporation also had a significant antitumor effect. TIMP-3-treated tumor tissues had significant apoptosis by TUNEL assay. These results showed that overexpression of TIMP-3 inhibits invasion and proliferation of prostate cancer cells in vitro and inhibits tumor growth in vivo. The experiments suggest a potential use for TIMP-3 in the gene therapy of prostate cancer.

High TRAIL death receptor 4 and decoy receptor 2 expression correlates with significant cell death in pancreatic ductal adenocarcinoma patients

OBJECTIVES

The importance of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and TRAIL receptor expression in pancreatic carcinoma development is not known. To reveal the putative connection of TRAIL and TRAIL receptor expression profile to this process, we analyzed and compared the expression profile of TRAIL and its receptors in pancreatic tissues of both noncancer patients and patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Thirty-one noncancer patients and 34 PDAC patients were included in the study. TRAIL and TRAIL receptor expression profiles were determined by immunohistochemistry. Annexin V binding revealed the apoptotic index in pancreas. Lastly, the tumor grade, tumor stage, tumor diameter, perineural invasion, and number of lymph node metastasis were used for comparison purposes.

RESULTS

TRAIL decoy receptor 2 (DcR2) and death receptor 4 expression were up-regulated in PDAC patients compared with noncancer patients, and the ductal cells of PDAC patients displayed significant levels of apoptosis. In addition, acinar cells from PDAC patients had higher DcR2 expression but lower death receptor 4 expression. Increased DcR2 expression was also observed in Langerhans islets of PDAC patients.

CONCLUSIONS

Differential alteration of TRAIL and TRAIL receptor expression profiles in PDAC patients suggest that the TRAIL/TRAIL receptor system may play a pivotal role during pancreatic carcinoma development.

Molecular mechanisms of death ligand-mediated immune modulation: a gene therapy model to prolong islet survival in type 1 diabetes

Type 1 diabetes results from the T cell-mediated destruction of pancreatic beta cells. Islet transplantation has recently become a potential therapeutic approach for patients with type 1 diabetes. However, islet-graft failure appears to be a challenging issue to overcome. Thus, complementary gene therapy strategies are needed to improve the islet-graft survival following transplantation. Immune modulation through gene therapy represents a novel way of attacking cytotoxic T cells targeting pancreatic islets. Various death ligands of the TNF family such as FasL, TNF, and TNF-Related Apoptosis-Inducing Ligand (TRAIL) have been studied for this purpose. The over-expression of TNF or FasL in pancreatic islets exacerbates the onset of type 1 diabetes generating lymphocyte infiltrates responsible for the inflammation. Conversely, the lack of TRAIL expression results in higher degree of islet inflammation in the pancreas. In addition, blocking of TRAIL function using soluble TRAIL receptors facilitates the onset of diabetes. These results suggested that contrary to what was observed with TNF or FasL, adenovirus mediated TRAIL gene delivery into pancreatic islets is expected to be therapeutically beneficial in the setting of experimental models of type 1 diabetes. In conclusion; this study mainly reveals the fundamental principles of death ligand-mediated immune evasion in diabetes mellitus.

High levels of endogenous tumor necrosis factor-related apoptosis-inducing ligand expression correlate with increased cell death in human pancreas

OBJECTIVES

Type 1 diabetes (T1D) has been characterized by the T cell-mediated destruction of pancreatic beta cells. Although various members of the tumor necrosis factor (TNF) family, such as Fas ligand or TNF, have recently been implicated in the development of T1D, the lack of TNF-related apoptosis-inducing ligand (TRAIL) expression or function facilitates the onset of T1D. Thus, the goal of the present study was to investigate the expression profiles of TRAIL and its receptors in human pancreas.

METHODS

Pancreata of 31 patients were analyzed by immunohistochemistry using antibodies developed against TRAIL and its receptors. Apoptosis was confirmed by Annexin V-fluorescein isothiocyanate binding and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling assays.

RESULTS

Acinar cells displayed high levels of TRAIL and death receptor 4, but only low levels of death receptor 5. In contrast, only TRAIL and TRAIL decoy receptors (DcR1, DcR2) were detected in ductal cells. Similarly, Langerhans islets expressed only TRAIL and TRAIL decoy receptor. High levels of TRAIL expression in pancreas correlated with increased number of apoptotic cells.

CONCLUSIONS

Although the expression of TRAIL decoy receptors might be necessary for defense from TRAIL-induced apoptosis, high levels of TRAIL may provide protection for Langerhans islets from the immunological attack of cytotoxic T cells.