ASB3 promotes hepatocellular carcinoma progression by mediating DR5 ubiquitination in TRAIL resistance.

Ankyrin-repeat proteins with a suppressor of cytokine signaling box (ASB) proteins belong to the E3 ubiquitin ligase family. 18 ASB members have been identified whose biological functions are mostly unexplored. Here, we discovered that ASB3 was essential for hepatocellular carcinoma (HCC) development and high ASB3 expression predicted poor clinical outcomes. ASB3 silencing induced HCC cell growth arrest and apoptosis in vitro and in vivo. Liver-specific deletion of Asb3 gene suppressed diethylnitrosamine (DEN)-induced liver cancer development. Mechanistically, ASB3 interacted with death receptor 5 (DR5), which promoted ubiquitination and degradation of DR5. We further showed that ASB3 knockdown stabilized DR5 and increased the sensitivity of liver cancer cells to the treatment of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a DR5-dependent manner in cellular and in animal models. In summary, we demonstrated that ASB3 promoted ubiquitination and degradation of DR5 in HCC, suggesting the potential of targeting ASB3 to HCC treatment and overcome TRAIL resistance.

ELF3 plays an important role in defining TRAIL sensitivity in breast cancer by modulating the expression of decoy receptor 2 (DCR2).

BACKGROUND: TRAIL protein on binding to its cognate death receptors (DR) can induce apoptosis specifically in breast tumor cells sparing normal cells. However, TRAIL also binds to decoy receptors (DCR) thereby inhibiting the apoptotic pathways thus causing TRAIL resistance. Also, one of the barriers due to which TRAIL-based therapy could not become FDA-approved might be because of resistance to therapy. Therefore, in the current study we wanted to explore the role of transcription factors in TRAIL resistance with respect to breast cancer. METHODS: Microarray data from TRAIL-sensitive (TS) and TRAIL-resistant (TR) MDA-MB-231 cells were reanalyzed followed by validation of the candidate genes using quantitative PCR (qPCR), immunoblotting and immunofluorescence technique. Overexpression of the candidate gene was performed in MDA-MB-231 and MCF7 cells followed by cell viability assay and immunoblotting for cleaved caspase-3. Additionally, immunoblotting for DCR2 was carried out. TCGA breast cancer patient survival was used for Kaplan-Meier (KM) plot. RESULTS: Validation of the candidate gene i.e. ELF3 using qPCR and immunoblotting revealed it to be downregulated in TR cells compared to TS cells. ELF3 overexpression in MDA-MB-231 and MCF7 cells caused reversal of TRAIL resistance as observed using cell viability assay and cleaved caspase-3 immunoblotting. ELF3 overexpression also resulted in DCR2 downregulation in the MDA-MB-231 and MCF7 cells. Furthermore, KM analysis found high ELF3 and low DCR2 expression to show better patient survival in the presence of TRAIL. CONCLUSION: Our study shows ELF3 to be an important factor that can influence TRAIL-mediated apoptosis in breast cancer. Also, ELF3 and DCR2 expression status should be taken into consideration while designing strategies for successful TRAIL-based therapy.

IL-8 and PI3K pathway influence the susceptibility of TRAIL-sensitive colorectal cancer cells to TRAIL-induced cell death.

BACKGROUND: Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is an apoptosis inducer that exhibits an ideal therapeutic safety profile with less adverse effects than conventional chemotherapy. However, the occurrence of TRAIL resistance has been reported in various cancers including colorectal cancer (CRC). Substantial efforts have been channelled towards managing TRAIL resistance including identifying molecular targets. Interleukins (ILs) have been recently shown to play critical roles in modulating TRAIL sensitivity in cancer cells. METHODS AND RESULTS: This study investigated the roles of two ILs, IL-8 and IL⍺, in TRAIL resistance in CRC. TRAIL-resistant HT-29 and TRAIL-sensitive HCT 116 cells, were treated with human recombinant IL-8 and IL-1⍺. The results indicated that treatment with IL-8 (2.5 ng/mL) significantly protected TRAIL-sensitive HCT 116 cells from TRAIL-induced cell death (p < 0.05). However, IL-1⍺ did not play a role in modulating CRC cells' responses to TRAIL. Data from RT-qPCR and Western blotting revealed the molecular regulations of IL-8 on TRAIL decoy receptor genes (OPG) and autophagy-related genes (BECN1 and LC3B) expression. The activation of the phosphoinositide 3-kinase (PI3K) pathway was shown to counteract TRAIL-induced cell death. By inhibiting its activation with wortmannin, the protective role of IL-8 against TRAIL treatment was reversed, suggesting the involvement of the PI3K pathway. CONCLUSION: Collectively, findings from this study identified the role of IL-8 and PI3K in modulating CRC cells' sensitivity to TRAIL. Further validation of these two potential molecular targets is warranted to overcome TRAIL resistance in CRC.

Acquired Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) Resistance of Human Colorectal Cancer Cells Is Linked to Histone Acetylation and Is Synergistically Ameliorated by Combination with HDAC Inhibitors.

BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an attractive target for the treatment of various malignancies; however, its therapeutic potential is limited because of the frequent occurrence of tumor cell resistance. In this study, we determined whether TRAIL resistance acquired by repeated administration could be overcome by HDAC inhibition in human colorectal cancer cells. METHODS: TRAIL-resistant HCT116 human colorectal cancer cells (HCT116-TR) were generated by repeated treatment with 10 and 25 ng/mL TRAIL twice weekly for 28 days. RESULTS: The resulting TRAIL-resistant cells were noncross-resistant to other chemotherapeutic agents. The levels of histone acetylation-related proteins, such as ac-histone H4 and HDAC1, were altered in HCT116-TR cells compared with the parental HCT116 cell line. The combined treatment with TRAIL and HDAC inhibitors significantly increased apoptosis in HCT116-TR cells and indicated a synergistic effect. The mechanism by which HDAC inhibition sensitizes HCT116-TR cells to TRAIL is dependent on the intrinsic pathway. In addition, we found that HDAC inhibition enhanced the sensitivity of cells to TRAIL through mitogen-activated protein kinases/CCAAT/enhancer-binding protein homologs of protein-dependent upregulation of death receptor 5. CONCLUSION: These results suggest that histone acetylation is responsible for acquired TRAIL resistance after repeated exposure and acquired resistance to TRAIL may be overcome by combination therapies with HDAC inhibitors.

Selective CDK9 knockdown sensitizes TRAIL response by suppression of antiapoptotic factors and NF-kappaB pathway.

The aberrantly up-regulated CDK9 can be targeted for cancer therapy. The CDK inhibitor dinaciclib (Dina) has been found to drastically sensitizes cancer response to TRAIL-expressing extracellular vesicle (EV-T). However, the low selectivity of Dina has limited its application for cancer. We propose that CDK9-targeted siRNA (siCDK9) may be a good alternative to Dina. The siCDK9 molecules were encapsulated into EV-Ts to prepare a complexed nanodrug (siEV-T). It was shown to efficiently suppress CDK9 expression and overcome TRAIL resistance to induce strikingly augmented apoptosis in lung cancer both in vitro and in vivo, with a mechanism related to suppression of both anti-apoptotic factors and nuclear factor-kappa B pathway. Therefore, siEV-T potentially constitutes a novel, highly effective and safe therapy for cancers.

CDH1 overexpression sensitizes TRAIL resistant breast cancer cells towards rhTRAIL induced apoptosis.

PURPOSE: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is well known for its unique ability to induce apoptosis in cancer cells but not normal cells. However, a subpopulation of cancer cells exist that does not respond to toxic doses of TRAIL. In this study, we aimed to identify key factors regulating TRAIL resistance in breast cancer. METHODS: rhTRAIL (recombinant human TRAIL) resistant cells (TR) isolated from TRAIL sensitive MDA-MB-231 parental cells (TS) were confirmed using trypan blue assay, cell viability assay and AO/EtBr (acridine orange/ethidium bromide) staining. Microarray was performed followed by analysis using DAVID and Cytoscape bioinformatics software to identify the candidate hub gene. Gene expression of the candidate gene was confirmed using real-time PCR and western blot. Candidate gene was overexpressed via transient transfection to identify its significance in the context of rhTRAIL. Breast cancer patient data was obtained from The Cancer Genome Atlas (TCGA) database. RESULTS: Whole transcriptome analysis identified 4907 differentially expressed genes (DEGs) between TS and TR cells. CDH1 was identified as the candidate hub gene, with 18-degree centrality. We further observed CDH1 protein to be downregulated, overexpression of which increased apoptosis in TR cells after rhTRAIL treatment. TCGA patient data analysis also showed CDH1 mRNA to be low in TRAIL resistant patient group compared to TRAIL sensitive group. CONCLUSION: CDH1 overexpression sensitizes TR cells towards rhTRAIL induced apoptosis. Therefore, we can hypothesize that CDH1 expression should be taken into account while performing TRAIL therapy in breast cancer.

Isolation of Various Flavonoids with TRAIL Resistance-Overcoming Activity from Blumea lacera.

Eighteen compounds, including fourteen flavonoids (1-14), one steroid (15), two fatty acids (16,17), and one nitrogen-containing compound (18), were isolated from the methanol extract of the whole Blumea lacera plant collected in Thailand. Compounds 1-11 and 15-17 exhibited tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance-overcoming activity. Among them, bonanzin (2) and cirsilineol (7) had particularly strong TRAIL resistance-overcoming activity, where the IC50 values against the human gastric adenocarcinoma cell line AGS in the presence of TRAIL (100 ng/mL) were 10.7 µM and 5.9 µM, respectively.

Micelle-in-Liposomes for Sustained Delivery of Anticancer Agents That Promote Potent TRAIL-Induced Cancer Cell Apoptosis.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces cancer cell-specific apoptosis and has garnered intense interest as a promising agent for cancer treatment. However, the development of TRAIL has been hampered in part because most human cancer cells are resistant to TRAIL. A few small molecules including natural compounds such as piperlongumine (PL) have been reported to sensitize cancer cells to TRAIL. We prepared a novel type of nanomaterial, micelle-in-liposomes (MILs) for solubilization and delivery of PL. PL-loaded MILs were used to sensitize cancer cells to TRAIL. As visualized by cryo-TEM, micelles were successfully loaded inside the aqueous core of liposomes. The MILs increased the water solubility of PL by ~20 fold. A sustained PL release from MILs in physiologically relevant buffer over 7 days was achieved, indicating that the liposomes prevented premature drug release from the micelles in the MILs. Also demonstrated is a potent synergistic apoptotic effect in cancer cells by PL MILs in conjunction with liposomal TRAIL. MILs provide a new formulation and delivery vehicle for hydrophobic anticancer agents, which can be used alone or in combination with TRAIL to promote cancer cell death.

ISG12a and its interaction partner NR4A1 are involved in TRAIL-induced apoptosis in hepatoma cells.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in cancer cells while sparing normal cells, thereby leading to the development of TRAIL receptor agonists for cancer treatment. However, these agonist-based therapeutics exhibit little clinical benefits due to the lack of biomarkers to predict whether patients are responsive to the treatment, as well as determine the resistance of cancer cells to TRAIL-based agonists. Our previous study has demonstrated that ISG12a enhances TRAIL-induced apoptosis and might serve as a biomarker to predict the TRAIL response. The downstream mechanism by which ISG12a augments TRAIL-induced apoptosis remains to be elucidated. In this study, we found that ISG12a was localized in the mitochondria and nucleus and augmented TRAIL-induced apoptosis through intrinsic apoptotic pathway. In addition, ISG12a interacted with NR4A1 and promoted its nuclear-to-cytoplasm translocation. Upon translocate to cytoplasm, NR4A1 targeted mitochondria and induced Bcl2 conformational change, thereby exposing its BH3 domain. Moreover, TRAIL treatment can induce NR4A1 expression through the activation of NF-κB in TRAIL-resistant Huh7 hepatoma cells. Knockdown of NR4A1 could overcome TRAIL resistance. However, in TRAIL-sensitive LH86 liver cancer cells, TRAIL activated the Jun N-terminal kinases signalling pathway. Overall, these results showed that both ISG12a and its interaction partner NR4A1 are involved in TRAIL-mediated apoptosis in hepatoma cells.

3-Bromopyruvate potentiates TRAIL-induced apoptosis in human colon cancer cells through a reactive oxygen species- and caspase-dependent mitochondrial pathway.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising anticancer cytokine with minimal toxicity towards normal cells. Nevertheless, most primary cancers are often intrinsically TRAIL-resistant or can acquire resistance after TRAIL therapy. This study aimed to investigate the inhibitory effect of co-treatment of 3-bromopyruvate (3-BP) as a potent anticancer agent with TRAIL on colon cancer cells (HT-29). The results of present study indicated that combined treatment with 3-BP and TRAIL inhibited the proliferation of HT-29 cells to a greater extent (88.4%) compared with 3-BP (54%) or TRAIL (11%) treatment alone. In contrast, the combination of 3-BP and TRAIL had no significant inhibitory effect on the proliferation of normal cells (HEK-293) (8.4%). At a cellular mechanistic level, the present study showed that 3-BP sensitized human colon cancer cells to TRAIL-induced apoptosis via reactive oxygen species generation, upregulation of Bax, downregulation of Bcl-2 and survivin, release of cytochrome c into the cytosol, and activation of caspase-3. In normal cells, 3-BP, TRAIL, or combination of both had no significant effect on the reactive oxygen species levels, release of cytochrome c, and caspase-3 activity. Therefore, the combination of 3-BP and TRAIL can be a promising therapeutic strategy for treatment of colon cancer.

Improved Anticancer Effect of Recombinant Protein izTRAIL Combined with Sorafenib and Peptide iRGD.

One of the main problems in oncology is the development of drugs that cause the death of cancer cells without damaging normal cells. Another key problem to be solved is to suppress the drug resistance of cancer cells. The third important issue is to provide effective penetration of drug molecules to cancer cells. TRAIL (TNFα-related apoptosis inducing ligand)/Apo2L is a highly selective anticancer agent. However, the recombinant TRAIL protein having high efficiency against cancer cells in vitro was not effective in clinical trials. Recently we have discovered an acquisition of TRAIL resistance by cancer cells in confluent cultures, which is apparently a manifestation of the general phenomenon of multicellular resistance. The aim of this study was to evaluate whether the anticancer effect of the recombinant protein TRAIL in vivo can be improved by the suppression of multicellular TRAIL-resistance using sorafenib and a tumor-penetrating peptide iRGD, c(CRGDKGPDC). The results testified a great increase in the resistance of human fibrosarcoma HT-1080 cells to izTRAIL both in confluent cultures and in spheroids. Sorafenib administered at nontoxic concentration effectively suppressed confluent- or spheroid-mediated TRAIL-resistance of HT-1080 cells in vitro. Sorafenib combined with iRGD significantly improved the anticancer effect of the recombinant protein izTRAIL in HT-1080 human fibrosarcoma grafts in BALB/c nude mice. Consistent with this finding, multicellular TRAIL-resistance may be a reason of inefficacy of izTRAIL alone in vivo. The anticancer effect of the recombinant protein izTRAIL in vivo may be improved in combination with sorafenib, an inhibitor of multicellular TRAIL resistance and iRGD, the tumor-penetrating peptide.

Involvement of p38 Activation and Mitochondria in Death of Human Leukemia Cells Induced by an Agonistic Human Monoclonal Antibody Fab Specific to TRAIL Receptor 1.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces cancer cell death with minimal damage to normal cells; however, some cancer cells are resistant to TRAIL. TRAIL resistance may be overcome by agonistic antibodies to TRAIL receptors. In this study, we report the toxic effects of a novel recombinant agonistic human anti-TRAIL receptor 1 (DR4) monoclonal antibody Fab fragment, DR4-4, on various TRAIL-resistant and -sensitive cancer cell lines. The mechanisms of DR4-4 Fab-induced cell death in a human T cell leukemia cell line (Jurkat) were investigated using cell viability testing, immunoblotting, immunoassays, flow cytometry, and morphological observation. DR4-4 Fab-induced caspase-independent necrosis was observed to occur in Jurkat cells in association with p38 mitogen-activated protein kinase activation, cellular FLICE (FADD-like IL-1ß-converting enzyme)-inhibitory protein degradation, decreased mitochondrial membrane potential, and increased mitochondrial reactive oxygen species production. Increased cytotoxic effects of DR4-4 Fab were observed in combination with TRAIL or γ-irradiation. Our results indicate that the novel DR4-4 Fab might overcome TRAIL-resistance and induce death in leukemia cells via cellular mechanisms different from those activated by TRAIL. DR4-4 Fab may have application as a potential therapeutic antibody fragment in single or combination therapy for cancer.

Chaetospirolactone reverses the apoptotic resistance towards TRAIL in pancreatic cancer.

The pancreatic cancer is one of the most aggressive tumors. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can trigger apoptosis by interaction with death receptors. However, in TRAIL-resistant pancreatic cancer, responsiveness to TRAIL treatment is terribly poor. In current work, we have demonstrated that a natural product chaetospirolactone (CSL) isolated from an endophytic fungus Chaetomium sp. NF00754 can enhance the susceptibility of TRAIL-resistant pancreatic cancer cells to apoptosis. CSL can induce apoptosis in TRAIL-treated pancreatic cancer cells. Furthermore, combined CSL and TRAIL treatment significantly inhibits viability and migration of pancreatic cancer cells. Combinatorial TRAIL and CSL treatment repressed xenograft tumor growth without substantially toxic side effects. CSL can specifically upregulate expression of death receptor 4 (DR4). Further study revealed that CSL represses the activities of an epigenetic regulator enhancer of zeste homolog 2 (EZH2) and consistently reduces histone H3 lysine 27 trimethylation (H3K27me3) to allow DR4 transcription. Taken together, CSL treatment may reverse TRAIL resistance in pancreatic cancer cells via epigenetic regulation of DR4 implying that administration of CSL might represent a putative strategy for pancreatic cancer therapy.

Intracellular localization of DR5 and related regulatory pathways as a mechanism of resistance to TRAIL in cancer.

TNF-related apoptosis-inducing ligand (TRAIL) is a prominent cytokine capable of inducing apoptosis. It can bind to five different cognate receptors, through which diverse intracellular pathways can be activated. TRAIL's ability to preferentially kill transformed cells makes it a promising potential weapon for targeted tumor therapy. However, recognition of several resistance mechanisms to TRAIL-induced apoptosis has indicated that a thorough understanding of the details of TRAIL biology is still essential before this weapon can be confidently unleashed. Critical to this aim is revealing the functions and regulation mechanisms of TRAIL's potent death receptor DR5. Although expression and signaling mechanisms of DR5 have been extensively studied, other aspects, such as its subcellular localization, non-signaling functions, and regulation of its membrane transport, have only recently attracted attention. Here, we discuss different aspects of TRAIL/DR5 biology, with a particular emphasis on the factors that seem to influence the cell surface expression pattern of DR5, along with factors that lead to its nuclear localization. Disturbance of this balance apparently affects the sensitivity of cancer cells to TRAIL-mediated apoptosis, thus constituting an eligible target for potential new therapeutic agents.

A set of NF-κB-regulated microRNAs induces acquired TRAIL resistance in lung cancer.

TRAIL (TNF-related apoptosis-inducing ligand) is a promising anticancer agent that can be potentially used as an alternative or complementary therapy because of its specific antitumor activity. However, TRAIL can also stimulate the proliferation of cancer cells through the activation of NF-κB, but the exact mechanism is still poorly understood. In this study, we show that chronic exposure to subtoxic concentrations of TRAIL results in acquired resistance. This resistance is associated with the increase in miR-21, miR-30c, and miR-100 expression, which target tumor-suppressor genes fundamental in the response to TRAIL. Importantly, down-regulation of caspase-8 by miR-21 blocks receptor interacting protein-1 cleavage and induces the activation of NF-κB, which regulates these miRNAs. Thus, TRAIL activates a positive feedback loop that sustains the acquired resistance and causes an aggressive phenotype. Finally, we prove that combinatory treatment of NF-κB inhibitors and TRAIL is able to revert resistance and reduce tumor growth, with important consequences for the clinical practice.

Novel TRAIL sensitizer Taraxacum officinale F.H. Wigg enhances TRAIL-induced apoptosis in Huh7 cells.

TRAIL (TNF-related apoptosis inducing ligand) is a promising anti-cancer drug target that selectively induces apoptosis in cancer cells. However, many cancer cells are resistant to TRAIL-induced apoptosis. Therefore, reversing TRAIL resistance is an important step for the development of effective TRAIL-based anti-cancer therapies. We previously reported that knockdown of the TOR signaling pathway regulator-like (TIPRL) protein caused TRAIL-induced apoptosis by activation of the MKK7-c-Jun N-terminal Kinase (JNK) pathway through disruption of the MKK7-TIPRL interaction. Here, we identified Taraxacum officinale F.H. Wigg (TO) as a novel TRAIL sensitizer from a set of 500 natural products using an ELISA system and validated its activity by GST pull-down analysis. Furthermore, combination treatment of Huh7 cells with TRAIL and TO resulted in TRAIL-induced apoptosis mediated through inhibition of the MKK7-TIPRL interaction and subsequent activation of MKK7-JNK phosphorylation. Interestingly, HPLC analysis identified chicoric acid as a major component of the TO extract, and combination treatment with chicoric acid and TRAIL induced TRAIL-induced cell apoptosis via JNK activation due to inhibition of the MKK7-TIPRL interaction. Our results suggest that TO plays an important role in TRAIL-induced apoptosis, and further functional studies are warranted to confirm the importance of TO as a novel TRAIL sensitizer for cancer therapy. © 2015 Wiley Periodicals, Inc.

Sesquiterpenes with TRAIL-resistance overcoming activity from Xanthium strumarium.

The ability of TRAIL to selectively induce apoptosis in cancer cells while sparing normal cells makes it an attractive target for the development of new cancer therapy. In search of bioactive natural products for overcoming TRAIL-resistance from natural resources, we previously reported a number of active compounds. In our screening program on natural resources targeting overcoming TRAIL-resistance, activity-guided fractionations of the extract of Xanthium strumarium led to the isolation of five sesquiterpene compounds (1-5). 11α,13-dihydroxanthinin (2) and 11α,13-dihydroxanthuminol (3) were first isolated from natural resources and xanthinosin (1), desacetylxanthanol (4), and lasidiol p-methoxybenzoate (5) were known compounds. All compounds (1-5) showed potent TRAIL-resistance overcoming activity at 8, 20, 20, 16, and 16 µM, respectively, in TRAIL-resistant AGS cells. Compounds 1 and 5 enhanced the levels of apoptosis inducing proteins DR4, DR5, p53, CHOP, Bax, cleaved caspase-3, cleaved caspase-8, and cleaved caspase-9 and also decreased the levels of cell survival protein Bcl-2 in TRAIL-resistant AGS cells in a dose-dependent manner. Compound 1 also enhanced the levels of DR4 and DR5 proteins in a time-dependent manner. Thus, compounds 1 and 5 were found to induce both extrinsic and intrinsic apoptotic cell death. Compound 1 also exhibit TRAIL-resistance overcoming activity in DLD1, DU145, HeLa, and MCF7 cells but did not decrease viability in non-cancer HEK293 cells up to 8 µM.

C-FLIP(L) contributes to TRAIL resistance in HER2-positive breast cancer.

Breast cancers with HER2 amplification have a poorer prognosis than the luminal phenotypes. TRAIL activates apoptosis upon binding its receptors in some but not all breast cancer cell lines. Herein, we investigated the expression pattern of c-FLIP(L) in a cohort of 251 invasive breast cancer tissues and explored its potential role in TRAIL resistance. C-FLIP(L) was relatively high-expressed in HER2-positive breast cancer in comparison with other molecular subtypes, co-expressed with TRAIL death receptors, and inversely correlated with the apoptosis index. Downregulation of c-FLIP(L) sensitized SKBR3 cells to TRAIL-induced apoptosis in a concentration- and time-dependent manner and enhanced the activities and cleavages of caspase-8 and caspase-3, without altering the surface expression of death receptors. Together, our results indicate that c-FLIP(L) promotes TRAIL resistance and inhibits caspase-3 and caspase-8 activation in HER2-positive breast cancer.

Isolation of bioactive phytochemicals from Crinum asiaticum L. along with their cytotoxic and TRAIL-resistance abrogating prospect assessment.

Crinum asiaticum L. (Amaryllidaceae) is a perennial bulbous herb, locally utilized for possessing multifaceted pharmacological properties including anticancer, immune-stimulating, analgesic, antiviral, antimalarial, antibacterial and antifungal, in addition to its popularity as an aesthetic plant. Separation of MeOH extract of C. asiaticum leaves yielded three known compounds as cycloneolitsol (1), hippeastrine (2) and ß-sitosterol (3). Among these, compounds 1 and 2 were subjected to the cytotoxic assay and found that they induced mild effect against HCT116, Huh7 and DU145 cell lines with the IC50 values from 73.76 to 132.53 µM. When tested for TRAIL-resistance abrogating activity, 1 (100 µM) along with TRAIL (100 ng/mL) showed moderate activity in AGS cells producing 25 % more inhibition than the agent alone. Whereas 2 (20 and 30 µM) in combination with TRAIL (100 ng/mL) exhibited strong activity in abrogating TRAIL-resistance and caused 34 % and 36 % more inhibition in AGS cells, respectively. The in-silico studies of compound 2 revealed high docking hits with the TRAIL-associated anti-apoptotic proteins which give a justification for the regulatory interactions to induce such abrogating activity. It is still recommended to conduct further investigations to understand their exact molecular mechanism.

Combining the constitutive TRAIL-secreting induced neural stem cell therapy with the novel anti-cancer drug TR-107 in glioblastoma.

Tumor-homing neural stem cell (NSC) therapy is emerging as a promising treatment for aggressive cancers of the brain. Despite their success, developing tumor-homing NSC therapy therapies that maintain durable tumor suppression remains a challenge. Herein, we report a synergistic combination regimen where the novel small molecule TR-107 augments NSC-tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) therapy (hiNeuroS-TRAIL) in models of the incurable brain cancer glioblastoma (GBM) in vitro. We report that the combination of hiNeuroS-TRAIL and TR-107 synergistically upregulated caspase markers and restored sensitivity to the intrinsic apoptotic pathway by significantly downregulating inhibitory pathways associated with chemoresistance and radioresistance in the TRAIL-resistant LN229 cell line. This combination also showed robust tumor suppression and enhanced survival of mice bearing human xenografts of both solid and invasive GBMs. These findings elucidate a novel combination regimen and suggest that the combination of these clinically relevant agents may represent a new therapeutic option with increased efficacy for patients with GBM.