Comprehensive expression analysis of TNF-related apoptosis-inducing ligand and its receptors in colorectal cancer: Correlation with MAPK alterations and clinicopathological associations

Escaping cell death via TRAIL decoy receptors: a systematic review of their roles and expressions in colorectal cancer

The development of targeted therapy such as tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-based therapy has gained increasing attention as a promising new approach in cancer therapy. TRAIL specifically targets cancer cells while sparing the normal cells, thus, limiting the known side effects of the majority anti-cancer therapies. As more extensive research and clinical trials are conducted, resistance to TRAIL molecule has become one of the significant issues associated with the failure of TRAIL in treating colorectal cancer (CRC). To date, the exact mechanism by which TRAIL resistance may have occurred remains unknown. Interestingly, recent studies have revealed the critical role of the TRAIL decoy receptor family; consisting of decoy receptor 1 (DcR1; also known as TRAIL-R3), decoy receptor 2 (DcR2; also known as TRAIL-R4), and osteoprotegerin (OPG) in driving TRAIL resistance. This review highlights the expression of the decoy receptors in CRC and its possible association with the reduction in sensitivity towards TRAIL treatment based on the currently available in vitro, in vivo, and human studies. Additionally, discrepancies between the outcomes from different research groups are discussed, and essential areas are highlighted for future investigation of the roles of decoy receptors in modulating TRAIL-induced apoptosis. Overcoming TRAIL resistance through modulating the expression(s) and elucidating the role(s) of TRAIL decoy receptors hold great promise for TRAIL-based therapies to be extensively explored in treating human cancers including CRC.

MTOR/4EBP1 signaling and MMR status in colorectal cancer: New correlations and arising perspectives

This is the first study aiming to investigate mTOR signaling and its relation to mismatch repair status (MMR status) in colorectal cancer (CRC). MMR status and the phosphorylated proteins, pmTOR and p4EBP1, have been immunohistochemically analyzed in 108 formalin-fixed, paraffin-embedded CRC specimens. The correlations between them and with clinicopathological data, MAPK pathway (KRAS, NRAS, BRAF) as well as their impact on patients' overall survival have been statistically analyzed. Our results indicated that positive pmTOR expression was significantly associated with KRAS mutations (p = 0.004). From multivariate survival analysis, only p4EBP1 expression emerged as independent adverse prognostic factor for overall survival (HR, 3.322; 95%CI, 1.110-9.945; p = 0.032). Furthermore, MMR deficient carcinomas tend to express low p4EBP1 protein levels (p = 0.002). A survival analysis stratified by MMR status and p4EBP1 expression, showed that MMR proficient tumours with high p4EBP1 expression had the worst overall survival compared with the other examined subgroups (p = 0.019). In conclusion, MAPK and PI3k/Akt pathways seem to be simultaneously overactivated in CRC. P4EBP1 could be used as a prognostic biomarker. By further analyzing the significant association between MMR status and p4EBP1 expression, we suggest that MMR deficient tumours could represent a subpopulation most likely to derive treatment benefit from mTOR inhibition.

Revisiting the role of TRAIL/TRAIL-R in cancer biology and therapy

TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, can induce apoptosis in cancer cells, sparing normal cells when bound to its associated death receptors (DR4/DR5). This unique mechanism makes TRAIL a potential anticancer therapeutic agent. However, clinical trials of recombinant TRAIL protein and TRAIL receptor agonist monoclonal antibodies have shown disappointing results due to its short half-life, poor pharmacokinetics and the resistance of the cancer cells. This review summarizes TRAIL-induced apoptotic and survival pathways as well as mechanisms leading to apoptotic resistance. Recent development of methods to overcome cancer cell resistance to TRAIL-induced apoptosis, such as protein modification, combination therapy and TRAIL-based gene therapy, appear promising. We also discuss the challenges and opportunities in the development of TRAIL-based therapies for the treatment of human cancers.

Autophagy-related Proteins as a Prognostic Factor of Patients With Colorectal Cancer

Supplemental Digital Content is available in the text.

Autophagy plays a dual role in tumorigenesis. In the initial stages, it promotes cell survival and suppresses carcinogenesis, whereas in cancer development, it induces cancer cell survival. In this study, we investigate the role of autophagy as a protective or tumor suppressor mechanism in colorectal cancer (CRC) cell lines and evaluate its role as a potential biomarker in human tumor samples.

TRAIL receptors are differentially regulated and clinically significant in gallbladder cancer

Deregulation of the receptors of TNF-related apoptosis inducing ligand (TRAIL) has been reported in various cancers. In an effort to define the role of these receptors we profiled their expression in gallbladder cancer (GBC) and explored their clinical significance. Expression of TRAIL receptors' mRNA in GBC was analysed through reverse transcriptase polymerase chain reaction (RT-PCR), and protein through western blotting, immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). mRNA data show frequent higher expression of TRAIL receptors in GBC samples. Death receptors DR4 and DR5 showed significant negative correlation with tumour stage, T stage and tumour grade; DcR1 transcript showed positive correlation with tumour stage, N stage, M stage and tumour grade. Similarly, IHC showed frequent positive staining for DR4, DR5 and DcR1in GBC samples. Cytoplasmic and nuclear DR4 protein showed negative correlation with T stage and tumour grade, whereas cytoplasmic DcR1 protein showed positive correlation with tumour stage and N stage. Nuclear DcR1 showed positive correlation with N stage. ELISA results showed significantly higher expression of secretory DcR1 in GBC patients. Kaplan-Meier analysis demonstrated significantly decreased mean survival of patients with positive staining of cytoplasmic DcR1. High level of death receptors identified the patients with early gallbladder cancer, whereas high DcR1 expression served as a prognostic factor for poor outcome.