Functional expression of TRAIL receptors TRAIL-R1 and TRAIL-R2 in esophageal adenocarcinoma

Carboxypeptidase A4 negatively regulates HGS-ETR1/2-induced pyroptosis by forming a positive feedback loop with the AKT signalling pathway

Pyroptosis, a mode of inflammatory cell death, has recently gained significant attention. However, the underlying mechanism remains poorly understood. HGS-ETR1/2 is a humanized monoclonal antibody that can bind to DR4/5 on the cell membrane and induce cell apoptosis by activating the death receptor signalling pathway. In this study, by using morphological observation, fluorescence double staining, LDH release and immunoblot detection, we confirmed for the first time that HGS-ETR1/2 can induce GSDME-mediated pyroptosis in hepatocellular carcinoma cells. Our study found that both inhibition of the AKT signalling pathway and silencing of CPA4 promote pyroptosis, while the overexpression of CPA4 inhibits it. Furthermore, we identified a positive regulatory feedback loop is formed between CPA4 and AKT phosphorylation. Specifically, CPA4 modulates AKT phosphorylation by regulating the expression of the AKT phosphatase PP2A, while inhibition of the AKT signalling pathway leads to a decreased transcription and translation levels of CPA4. Our study reveals a novel mechanism of pyroptosis induced by HGS-ETR1/2, which may provide a crucial foundation for future investigations into cancer immunotherapy.

Trail armed oncolytic poxvirus suppresses lung cancer cell by inducing apoptosis

Lung cancer has a high morbidity rate worldwide and is often resistant to therapy. Oncolytic virus therapy is a developing trend for cancer treatment. Thus, we constructed an oncolytic poxvirus carrying human trail gene that expresses a membrane-binding tumor necrosis factor and associated apoptosis-inducing ligand (TRAIL, Oncopox-trail). We hypothesized that the expression of trail would increase the efficacy of the oncolytic poxvirus. The effect of the TRAIL protein depends on the death receptors on the surface of different cancer cells. The expression of death receptors in lung cancer cell lines was analyzed by western blot analysis. In vitro, the oncolytic poxvirus carrying the trail gene displayed a better cytotoxicity at the cell level in the lung cancer cell line than that carrying the Oncopox-empty. TRAIL protein mainly induced apoptosis and inhibited necrosis. In vivo, two transplanted tumor models of human A549 lung cancer cells and mouse Lewis lung cancer cells were used to verify the anti-cancer effect of the oncolytic poxvirus carrying the trail gene. TUNEL staining results of the tumor histological sections also verified the anti-cancer effect. Similarly, through systemic administration of Oncopox-trail, the oncolytic poxvirus also exhibited anti-cancer effect.

Improvement of Pharmacokinetic Profile of TRAIL via Trimer-Tag Enhances its Antitumor Activity in vivo

TNF-related apoptosis-inducing ligand (TRAIL/Apo2L) has long been considered a tantalizing target for cancer therapy because it mediates activation of the extrinsic apoptosis pathway in a tumor-specific manner by binding to and trimerizing its functional receptors DR4 or DR5. Despite initial promise, both recombinant human TRAIL (native TRAIL) and dimeric DR4/DR5 agonist monoclonal antibodies (mAbs) failed in multiple human clinical trials. Here we show that in-frame fusion of human C-propeptide of α1(I) collagen (Trimer-Tag) to the C-terminus of mature human TRAIL leads to a disulfide bond-linked homotrimer which can be expressed at high levels as a secreted protein from CHO cells. The resulting TRAIL-Trimer not only retains similar bioactivity and receptor binding kinetics as native TRAIL in vitro which are 4-5 orders of magnitude superior to that of dimeric TRAIL-Fc, but also manifests more favorable pharmacokinetic and antitumor pharmacodynamic profiles in vivo than that of native TRAIL. Taken together, this work provides direct evidence for the in vivo antitumor efficacy of TRAIL being proportional to systemic drug exposure and suggests that the previous clinical failures may have been due to rapid systemic clearance of native TRAIL and poor apoptosis-inducing potency of dimeric agonist mAbs despite their long serum half-lives.

Esophageal cancer-selective expression of TRAIL mediated by MREs of miR-143 and miR-122

Esophageal cancer is one of the most common digestive system neoplasms and has a quite poor prognosis. TNF-related apoptosis-inducing ligand (TRAIL) induces the apoptosis in a wide range of cancer cells including esophageal cancers. However, TRAIL also activates apoptotic pathway in normal cells. To improve the specificity of TRAIL action, we employed the microRNA (miRNA) response elements (MREs) of miR-143 and miR-122 to restrict TRAIL expression mediated by an adenoviral vector (Ad-TRAIL-143-122) in esophageal cancer cells. The experiments showed that Ad-TRAIL-143-122 was able to highly express TRAIL in esophageal cancer cells, but not normal cells. The selective TRAIL expression also led to selective apoptosis in esophageal cancer cells. Ad-TRAIL-143-122 greatly reduced the viability of esophageal cancer cells without cytotoxicity to normal cells. In mice, Ad-TRAIL-143-122 suppressed the growth of esophageal cancer xenografts and protected liver from TRAIL-induced toxicity. In this study, we constructed a biologic vector that can express exogenous genes in a tumor-specific manner. This strategy can simultaneously treat cancer and prevent hepatoxicity and thus may be a promising way for esophageal cancer treatment.

Membrane expression of the death ligand trail receptors DR4 and DR5 in the normal endometrium, endometrial atypical hyperplasia and endometrioid endometrial cancer

To assess membrane expression of DR4 and DR5 in the normal endometrium (NE), endometrial atypical hyperplasia (EAH) and endometrioid endometrial cancer (EEC), the study examined 101 patients: 20 NE, 14 EAH and 67 EEC. The expression of DR4 and DR5 was examined and presented as the total score (TS). DR4 expression was seen in 18 NE, 11 EAH and 10 EEC. DR5 expression was seen in 20 NE, 13 EAH and 21 EEC. A strong correlation between type of endometrial tissue and TS of both receptors was identified. In EEC TS of DR4 and DR5 was not related to grading, staging or survival. Malignant transformation in the endometrium is related to reduction of membrane DR4 and DR5 expression. The level of membrane staining of the receptors in EEC is not dependent on grading and staging, and is not sufficient to predict survival in EEC patients.

Membrane expression of TRAIL receptors DR4, DR5, DcR1 and DcR2 in the normal endometrium, atypical endometrial hyperplasia and endometrioid adenocarcinoma: a tissue microarray study

Purpose

To evaluate the membrane expression of DR4, DR5, DcR1 and DcR2 in the normal endometrium (NE), atypical endometrial hyperplasia (AEH) and endometrioid adenocarcinoma (EAC).

Methods

The study comprised 197 patients: 20 NE, 18 AEH and 159 EAC. Tissue microarrays were constructed. Membrane expression of DR4, DR5, DcR1 and DcR2 was examined and presented as total score (TS).

Results

In EAC, the membrane expression of DR4, DR5 and DcR2 was less common compared to NE (p < 0.001; p < 0.001; p = 0.018) and AEH (p < 0.001; p < 0.001; p = 0.004). In EAC the membrane expression of DcR1 did not differ when compared to NE (p = 0.055) and AEH (p = 0.173). A strong correlation was found between the type of endometrial tissue (NE/AEH/EAC) and the TS of DR4 (p < 0.001), DR5 (p < 0.001), DcR1 (p = 0.033) and DcR2 (p < 0.001). In EAC, the TS of DR4, DR5, DcR1 and DcR2 was not related to grading and staging. In EAC, the membrane expression of DR5, but not DR4, DcR1 and DcR2, was related to better disease-free survival (DFS). The overall survival (OS) was not related to membrane TRAIL receptors expression.

Conclusions

The membrane expression of the receptors for TRAIL DR4, DR5, DcR1 and DcR2 is greater in NE than EAC. The level of membrane staining of the receptors in EAC is not dependent on grading and staging. In EAC patients, membrane expression of DR4, DR5, DcR1 and DcR2 are not independent predictors of survival.

Emerging drugs for esophageal cancer

BACKGROUND

Cancer of the esophagus and gastro-esophageal junction is a disorder with a poor prognosis and increasing incidence.

OBJECTIVE

To provide a critical evaluation of current treatment strategies and new developments including targeted therapy for esophageal cancer.

METHODS

Published clinical trials as well as abstracts were selected regarding chemoradiation or targeted therapy for esophageal cancer.

RESULTS/CONCLUSIONS

Preoperative chemotherapy may offer a survival advantage compared to surgery alone, but the evidence is inconclusive. For preoperative chemoradiation, only 2 of 10 randomized trials showed advanced survival compared to surgery alone, and, therefore, more Phase III trials and, consequently, meta-analyses are needed. Until now, for palliative chemotherapy, no survival benefit has been shown. This is largely due to a lack of studies and difficulties in performing randomized trials. The application of targeted therapy is widespread and reported for several tumor types. For esophageal cancer, most studies have been performed with EGFR inhibitors, including cetuximab, gefitinib, erlotinib and trastuzumab. Limited experience is available with angiogenesis inhibitors, apoptosis inhibitors and COX-2 inhibitors. As yet, targeted therapies are proven to be safe often in combination with chemoradiation, but modestly effective for esophageal cancer. Phase III trials have not been published yet and, therefore, for targeted therapies also, possibly using new concepts, more studies are needed.

TRAIL receptor signalling and modulation: Are we on the right TRAIL?

Tumour necrosis factor-related apoptosis-inducing ligand or Apo2 ligand (TRAIL/Apo2L) is a member of the tumour necrosis factor (TNF) superfamily of cytokines that induces apoptosis upon binding to its death domain-containing transmembrane receptors, death receptors 4 and 5 (DR4, DR5). Importantly, TRAIL preferentially induces apoptosis in cancer cells while exhibiting little or no toxicity in normal cells. To date, research has focused on the mechanism of apoptosis induced by TRAIL and the processes involved in the development of TRAIL resistance. TRAIL-resistant tumours can be re-sensitized to TRAIL by a combination of TRAIL with chemotherapeutics or irradiation. Studies suggest that in many cancer cells only one of the two death-inducing TRAIL receptors is functional. These findings as well as the aim to avoid decoy receptor-mediated neutralization of TRAIL led to the development of receptor-specific TRAIL variants and agonistic antibodies. These molecules are predicted to be more potent than native TRAIL in vivo and may be suitable for targeted treatment of particular tumours. This review focuses on the current status of TRAIL receptor-targeting for cancer therapy, the apoptotic signalling pathway induced by TRAIL receptors, the prognostic implications of TRAIL receptor expression and modulation of TRAIL sensitivity of tumour cells by combination therapies. The mechanisms of TRAIL resistance and the potential measures that can be taken to overcome them are also addressed. Finally, the status of clinical trials of recombinant TRAIL and DR4-/DR5-specific agonistic antibodies as well as the pre-clinical studies of receptor-selective TRAIL variants is discussed including the obstacles facing the use of these molecules as anti-cancer therapeutics.

Prognostic significance of TRAIL-R1 and TRAIL-R3 expression in metastatic colorectal carcinomas

Drug resistance is believed to cause treatment failure in patients with metastatic colorectal carcinoma (CRC). Resistance to chemotherapy can involve different processes, including apoptosis, whose extrinsic pathway is regulated by expression of death-inducing TRAIL-R1 and -R2 and inhibitory TRAIL-R3 and -R4 cell surface receptors. Therefore, we investigated whether variations in their expression could influence the response to 5-Fluorouracil (5-FU) in metastatic CRC. We analysed TRAIL-R 1, -2, -3 and -4 expression by immuno-histochemistry in CRC, using tissue micro arrays, and found that concomitant low/medium TRAIL-R1 and high TRAIL-R3 expression in primary CRC is significantly associated with a poor response to 5-FU-based first-line chemotherapy and with shorter progression-free survival. Specifically, the median progression-free survival was 3.1 months (poor prognostic group) versus 10.1 in the good prognostic group. Thus, the combination of TRAIL-R1 and TRAIL-R3 expression might represent a predictive and prognostic factor of the response to 5-FU-based first-line chemotherapy in patients with metastatic CRC.

Novel targeted therapies for advanced esophageal cancer

Esophageal cancer is highly aggressive and is the sixth leading cause of cancer death worldwide. Recent advances in multimodality chemoradiotherapy and surgery has improved survival in patients with loco-regional disease, but most patients with advanced stage esophageal cancer have a poor prognosis. Elucidation of the processes involved in esophageal carcinogenesis has identified a number of promising novel targets for therapy. This review focuses on the current status of targeted therapies with potential application to the treatment of advanced esophageal and gastroesophageal junction cancer. The future challenge is to confirm the efficacy of these targeted agents in appropriately selected esophageal cancer patients, and successfully integrate these agents into effective therapies for all stages and subtypes of disease.

Lexatumumab (TRAIL-receptor 2 mAb) induces expression of DR5 and promotes apoptosis in primary and metastatic renal cell carcinoma in a mouse orthotopic model

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a variety of tumorigenic and transformed cell lines but not in many normal cells. Hence, TRAIL-agonist compounds have the potential of being excellent cancer therapeutic agents with minimal cytotoxicity. Here, we examine the efficacy of the TRAIL-receptor 2 agonist, lexatumumab (Human Genome Sciences, Inc., Rockville, MD), and identify molecular pathways that differentiate between lexatumumab-sensitive and lexatumumab-resistance renal cancer cells. In an orthotopic metastatic mouse model, we first demonstrate that lexatumumab was effective in reducing the tumor burden of primary and metastatic lexatumumab-sensitive xenografts. We demonstrate that lexatumumab-sensitive cells were capable of triggering both the extrinsic and the intrinsic apoptotic pathways as demonstrated by caspase 8 and caspase 9 activations, respectively, after treatment with lexatumumab. In addition, expression of c-FLIP(L) protein, an important regulator of TRAIL-induced apoptosis, decreased, while expression of the TRAIL-receptor 2, DR5, increased. This study serves as a pre-clinical model for using TRAIL-like therapies for patients with advanced RCC.