The NO TRAIL to YES TRAIL in cancer therapy (Review)

Clinical Cancer Research, 2007

Based on preclinical studies demonstrating that tumor necrosis factor^related apoptosis-inducing ligand (TRAIL) exerts a potent and cancer cell^specific proapoptotic activity, recombinant TRAIL as well as agonistic anti^TRAIL-R1and anti^TRAIL-R2 antibodies recently entered clinical trials. Additionally, gene therapy approaches using TRAIL-encoding adenovirus (Ad-TRAIL) are currently being developed to overcome the limitations inherent to TRAIL receptor targeting, i.e., pharmacokinetic of soluble TRAIL, pattern of receptor expression, and tumor cell resistance. To optimize gene therapy approaches, CD34 + cells transduced with Ad-TRAIL (CD34-TRAIL +) have been investigated as cellular vehicles forTRAIL delivery. Transduced cells exhibit a potent tumor killing activity on a variety of tumor cell types both in vitro and in vivo and are also cytotoxic against tumor cells resistant to solubleTRAIL. Studies in tumor-bearing nonobese diabetic/severe combined immunodeficient mice suggest that the antitumor effect of CD34-TRAIL + cells is mediated by both direct tumor cell killing due to apoptosis and indirect tumor cell killing due to vasculardisrupting mechanisms. The clinical translation of cell and gene therapy approaches represent a challenging strategy that might achieve systemic tumor targeting and increased intratumor delivery of the therapeutic agent.

Pharmacology & Therapeutics, 2015

TRAIL/Apo-2L is a member of the TNF superfamily first described as an apoptosis-inducing cytokine in 1995. Similar to TNF and Fas ligand, TRAIL induces apoptosis in caspase-dependent manner following TRAIL death receptor trimerization. Because tumor cells were shown to be particularly sensitive to this cytokine while normal cells/tissues proved to be resistant along with being able to synthesize and release TRAIL, it was rapidly appreciated that TRAIL likely served as one of our major physiologic weapons against cancer. In line with this, a number of research laboratories and pharmaceutical companies have attempted to exploit the ability of TRAIL to kill cancer cells by developing recombinant forms of TRAIL or TRAIL receptor agonists (e.g., receptor-specific mAb) for therapeutic purposes. In this review article we will describe the biochemical pathways used by TRAIL to induce different cell death programs. We will also summarize the clinical trials related to this pathway and discuss possible novel uses of TRAILrelated therapies. In recent years, the physiological importance of TRAIL has expanded beyond being a tumoricidal molecule to one critical for a number of clinical settings -ranging from infectious disease and autoimmunity to cardiovascular anomalies. We will also highlight some of these conditions where modulation of the TRAIL/TRAIL receptor system may be targeted in the future.

Biochemical and Biophysical Research Communications, 2010

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptors (TRAIL-R1 and TRAIL-R2) are promising targets for tumor therapy. However, their clinical use is limited because some tumors show resistance to TRAIL-treatment. Here, we analyzed epitopes of nine TRAIL-R1-specific human monoclonal antibodies and demonstrated at least five tentative epitopes on human TRAIL-R1. We found that some of the five were post-translationally modified on some tumor cell lines. Interestingly, one of them, an epitope of TR1-272 antibody (TR1-272-epitope) disappeared on the tumor cells that are more susceptible to TRAIL-induced apoptosis compared to TR1-272-epitope positive cells. Treatment of TR1-272-epitope negative cells with TRAIL induced large cluster formation of TRAIL-R1, while treatment of TR1-272-epiope positive cells with TRAIL did not. These results suggest that TR1-272-antibody might distinguish the TRAIL-R1 conformation that could deliver stronger death signals. Further analysis of epitope-appearance and sensitivity to TRAIL should clarify the mechanisms of TRAIL-induced apoptosis of tumor cells and would provide useful information about tumor therapy using TRAIL and TRAIL-R signaling.

Oncology Reports, 2009

The tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a specific and potent inducer of apoptosis in cancer cells, but the resistance of many tumour cells to TRAIL still represents a major hurdle for the clinical treatment of tumours with TRAIL. As apoptosis is regulated by the balance of activities of several anti-apoptotic factors and pro-apoptotic factors, we analysed the relative contribution of the two sides and found that down-regulation of Bcl-x L and in particular XIAP, but not c-Flip, sensitised the TRAIL resistant pancreatic cancer cell line Panc-1. A combination of both XIAP and Bcl-x L knockdowns showed no substantial added benefit indicating that both act in the same pathway. Notably, the degree of sensitisation by silencing of anti-apoptotic genes was further elevated by concomitantly increasing the pro-apoptotic potential in Panc-1 cells through over-expression of TRAIL-R1 or IFN-cmediated increases in caspase-8 levels. Similar sensitisation effects were obtained for another TRAILresistant pancreatic tumour cell line, AsPC-1. Our findings demonstrate that modulation of the balance between anti-and pro-apoptotic pathways from both sides by inhibition of apoptosis-antagonists and stimulation of pro-apoptotic factors provides the best way to enhance the anti-tumourigenic effect of TRAIL.

Cancer Biology & Therapy, 2007

Expert Opinion on Therapeutic Targets, 2007

Since its identification in 1995, TRAIL (TNF-Related Apoptosis Inducing Ligand) has sparked growing interest in oncology due to its reported ability to selectively trigger cancer cell death. Contrary to other members of the TNF superfamily, TRAIL administration in vivo is harmless. The relative absence of toxic side effects of this naturally occurring cytokine in addition to its antitumoral properties has led to its preclinical evaluation. However, despite intensive investigations, little is known with regard to the mechanisms underlying TRAIL selectivity or efficiency. Appropriate understanding of its physiological relevance, regulatory pathways and of the mechanisms controlling cancer cells escape to TRAIL-induced cell death will be required to optimally use the cytokine in clinics. The current review focuses on recent advances in the understanding of TRAIL signal transduction and discusses the current and future challenges of TRAIL-based cancer therapy development.

Oncogene, 2014

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in cancer cells while sparing normal tissues. Despite promising preclinical results, few patients responded to treatment with recombinant TRAIL (Apo2L/Dulanermin) or TRAIL-R2-specific antibodies, such as conatumumab (AMG655). It is unknown whether this was due to intrinsic TRAIL resistance within primary human cancers or insufficient agonistic activity of the TRAIL-receptor (TRAIL-R)-targeting drugs. Fcγ receptors (FcγR)-mediated crosslinking increases the cancer-cell-killing activity of TRAIL-R2-specific antibodies in vivo. We tested this phenomenon using FcγR-expressing immune cells from patients with ovarian cancer. However, even in the presence of high numbers of FcγR-expressing immune cells, as found in ovarian cancer ascites, AMG655-induced apoptosis was not enabled to any significant degree, indicating that this concept may not translate into clinical use. On the basis of these results, we next set out to determine whether AMG655 possibly interferes with apoptosis induction by endogenous TRAIL, which could be expressed by immune cells. To do so, we tested how AMG655 affected apoptosis induction by recombinant TRAIL. This, however, resulted in the surprising discovery of a striking synergy between AMG655 and non-tagged TRAIL (Apo2L/TRAIL) in killing cancer cells. This combination was as effective in killing cancer cells as highly active recombinant isoleucine-zipper-tagged TRAIL (iz-TRAIL). The increased killing efficiency was due to enhanced formation of the TRAIL death-inducing signalling complex, enabled by concomitant binding of Apo2L/TRAIL and AMG655 to TRAIL-R2. The synergy of AMG655 with Apo2L/TRAIL extended to primary ovarian cancer cells and was further enhanced by combination with the proteasome inhibitor bortezomib or a second mitochondrial-derived activator of caspases (SMAC) mimetic. Importantly, primary human hepatocytes were not killed by the AMG655-Apo2L/TRAIL combination, also not when further combined with bortezomib or a SMAC mimetic. We therefore propose that clinical-grade non-tagged recombinant forms of TRAIL, such as dulanermin, could be combined with antibodies such as AMG655 to introduce a highly active TRAIL-R2-agonistic therapy into the cancer clinic.

Molecular Cancer …, 2009

Recombinant human tumor necrosis factor-related apoptosis-inducing ligand (rhTRAIL) is being evaluated clinically in treating various malignancies. Previous studies have shown that repeated application of high doses of rhTRAIL results in a subpopulation of parental cells that is unresponsive to the death ligand. However, it is not clear whether TRAIL-sensitive cancer cells could acquire resistance to TRAIL treatment. Here, we found that MDA-MB-231 breast cancer cells, which are highly sensitive to TRAIL-induced apoptosis, became resistant to TRAIL killing after a prolonged exposure to subtoxic doses of rhTRAIL. The resulting TRAIL-resistant cells were cross-resistant to antibodies against its death receptors (DR4 and DR5); however, they retained sensitivity to several clinically relevant chemotherapies. Surface expression of DR4 and DR5 was significantly reduced in the selected cells, resulting in failure in death-inducing signaling complex formation and caspase activation. In addition, real-time PCR analysis revealed an upregulation in multiple apoptosis-regulator genes, including c-FLIP, Stat5a, and Stat5b. Inhibition of Janus-activated kinase, an upstream activator of signal transducer and activator of transcription 5 (Stat5), or knockdown of Stat5 itself partially restored cellular sensitivity to TRAIL-induced apoptosis, suggesting that Stat5 signaling is also involved in the development of TRAIL resistance. Furthermore, we showed that acquired TRAIL resistance was effectively eliminated by combination with etoposide, doxorubicin, or paclitaxel. These results suggest that tumor cells could acquire resistance to TRAIL therapy especially when they are repeatedly exposed to low levels of the death ligand, highlighting the necessity of combination with therapies that target the resistance mechanisms. (Mol Cancer Res mixture of three siRNA sequences (see Materials and Methods) targeting different regions of the human c-FLIP transcript. After 24 h, cells were analyzed by immunoblotting for c-FLIP protein expression (top) or treated with rhTRAIL (20 ng/mL) at 37°C for an additional 4 h followed by FACS analysis for apoptosis (bottom). E. The effect of Stat5b knockdown was assessed similarly as in D (top, immunoblots for Stat5 using an anti-pan Stat5 antibody recognizing both Stat5a and Stat5b, Bcl-XL, and cyclin D1; bottom, apoptosis after incubation with TRAIL for 4 h at 20 ng/mL). F. Cells were pretreated with a cell-permeable JAK kinase inhibitor at the indicated concentrations for 1 h, followed by rhTRAIL (20 ng/mL) for an additional 4 h. The results are expressed as JAK inhibitioninduced apoptosis (apoptosis % induced by JAK inhibitor combining with rhTRAIL − apoptosis % by rhTRAIL alone; n = 3, mean ± SD).

Oncology Letters, 2014

Biochemistry (Moscow), 2015

Tumor necrosis factor superfamily cytokine TRAIL (tumor necrosis factor related apoptosis inducing ligand) induces apoptosis in tumor cells by binding to death receptors DR4 and DR5 without affecting normal cells. However, the therapeutic use of TRAIL is limited, because many tumor cells are resistant to it. The resistance is partially related to inter action of TRAIL with the decoy receptors DcR1 and DcR2, which do not trigger the apoptotic signal and inhibit signaling of death receptors. Previously, we designed a unique DR5 specific TRAIL mutant variant DR5 B, which binds to DR5 receptor as effectively as the original cytokine, but has practically no interaction with DR4 and DcR1 receptors, and its affinity for DcR2 is reduced 400 fold. In the present work, the cytotoxity of TRAIL and DR5 B was analyzed on 12 differ ent tumor cell lines and two types of normal cells. In nine of 12 tumor cell lines, DR5 B killed 1.5 5.0 times more tumor cells than TRAIL, and it did not exhibit toxicity towards normal cells. Chemotherapeutic drugs such as doxorubicin, pacli taxel, and bortezomib augmented the effect of both TRAIL variants, and the enhancing effect was more pronounced for DR5 B. Half maximal effective concentrations (EC 50 ) for DR5 B in combination with chemotherapeutic agents were 1.5 10.0 times lower than for wild type TRAIL. Thus, DR5 B is a promising candidate both for monotherapy and in combina tion with chemotherapy for treatment of TRAIL resistant tumors.