Expression Of Death Receptor Research Articles

Modulation of Spheroid Forming Capacity and TRAIL Sensitivity by KLF4 and Nanog in Gastric Cancer Cells.

The expression of pluripotency factors, and their associations with clinicopathological parameters and drug response have been described in various cancers, including gastric cancer. This study investigated the association of pluripotency factor expression with the clinicopathological characteristics of gastric cancer patients, as well as changes in the expression of these factors upon the stem cell-enriching spheroid culture of gastric cancer cells, regulation of sphere-forming capacity, and response to cisplatin and TRAIL treatments by Nanog and KLF4. Nanog expression was significantly associated with the emergence of a new tumor and a worse prognosis in gastric cancer patients. The expression of the pluripotency factors varied among six gastric cancer cells. KLF4 and Nanog were expressed high in SNU-601, whereas SOX2 was expressed high in SNU-484. The expression of KLF4 and SOX2 was increased upon the spheroid culture of SNU-601 (KLF4/Nanog-high) and SNU-638 (KLF4/Nanog-low). The spheroid culture of them enhanced TRAIL-induced viability reduction, which was accompanied by the upregulation of death receptors, DR4 and DR5. Knockdown and overexpression of Nanog in SNU-601 and SNU-638, respectively, did not affect spheroid-forming capacity, however, its expression was inversely correlated with DR4/DR5 expression and TRAIL sensitivity. In contrast, KLF4 overexpression in SNU-638 increased spheroid formation, susceptibility to cisplatin and TRAIL treatments, and DR4/DR5 expression, while the opposite was found in KLF4-silenced SNU-601. KLF4 is supposed to play a critical role in DR4/DR5 expression and responses to TRAIL and cisplatin, whereas Nanog is only implicated in the former events only. Direct regulation of death receptor expression and TRAIL response by KLF4 and Nanog have not been well documented previously, and the regulatory mechanism behind the process remains to be elucidated.

Investigation of Apoptotic Effect of Klotho Protein on Human Colorectal Cancer Cells via TRAIL Death Receptors

Klotho is a transmembrane protein which is deficiency has pleiotropic effects in a number of aging-related disease processes and various cancers. In some recent studies about klotho protein disorders, it has been shown to klotho is effective in various cancers including lung, liver, breast, kidney, and colon. TNF-related apoptosis-inducing ligand (TRAIL), a TNF family molecule, is a cytokine that stimulates apoptosis through death receptors in many cancer types and therefore attracts attention for tumor therapies in various preclinical models. Interaction with TRAIL death receptors create an apoptotic effect in cancer treatments by reducing the proliferation of cancer cells. In this study, it was aimed to investigate the effects of exogen klotho administration on cell viability and apoptosis on TRAIL death receptors (TRAIL1 and TRAILR2) in human healthy colon cells (CCD 841 CoN) and TRAIL-resistant human colorectal cancer cells (caco2). For this purpose, cells were treated with different concentrations of klotho for 24 and 48 hours. To determine the cell viability, proliferation, and death receptors effects of klotho protein on cancer and healthy cells evaluations with WST-8 and Real-Time qRT-PCR analysis were performed. Our results showed that the increase in klotho protein concentration did not have a significant effect on cell viability in healthy colon cells, whereas it decreased cell viability and proliferation in apoptosis-resistant human colorectal cancer cells. Relative gene expression of TRAIL1 and TRAILR2 death receptors increased with klotho applied to the apoptosis-resistant colorectal cancer cell line caco-2. Therefore, targeting the ligand-receptors that induce TNF-related apoptosis with the klotho protein can be considered as a potential therapeutic approach for cancer therapy.

Decitabine enhances the tumoricidal potential of TRAIL via the epigenetic regulation of death receptor 4 in gastric cancer

Deoxyribonucleic acid (DNA) methyltransferase inhibitors, such as decitabine, have made great advances in cancer therapy as combinational drugs. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has an obvious anti-tumor effect; however, some gastric cancer (GC) cells are resistant to TRAIL-induced cell death. This study sought to explore the synergistic anti-tumor effect of TRAIL and decitabine, and the potential synergetic mechanism. The cell growth inhibition effect was monitored by the IncuCyte ZOOM Live-Cell Analysis System, and cell viability was determined by Cell Counting Kit-8 assays. Apoptosis was detected by Annexin V/Propidium Iodide double staining. Death receptor 4 (DR4) was knocked down by ribonucleic acid (RNA) interference, and the effect of DR4 deletion on TRAIL sensitivity was analyzed. Methylation-specific polymerase chain reaction (PCR) was applied to determine the methylation status of DR4. The messenger RNA (mRNA) and protein expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The expression of the DRs on the cell membrane surfaces was analyzed by flow cytometry. The combined use of decitabine and TRAIL synergistically inhibited cell growth in 2 TRAIL-resistant cell lines. Further, decitabine augmented TRAIL-induced apoptosis in a caspase-dependent manner. The co-application of decitabine and TRAIL facilitated the activation of caspase-7, -8, -9, and poly ADP-ribose polymerase (PARP). Notably, decitabine increased the expression of DR4 at the transcriptional and post-transcriptional levels. DR4 expression on the cell membrane surfaces was also upregulated after decitabine exposure. The depletion of DR4 by specific inhibitors attenuated TRAIL-induced apoptosis and weakened the synergistic effects of decitabine and TRAIL. In addition, DR4 gene presented methylation status in SNU-1 cells. The low mRNA and protein expression of DR4 were also detected in SNU-1 cells. Decitabine enhances the effect of TRAIL by inhibiting the growth and inducing the apoptosis of GC cells. This is achieved by the epigenetic modification of decitabine, which upregulates DR4. Decitabine may act as a sensitizing agent of TRAIL. The combined use of decitabine and TRAIL may provide a novel idea for GC treatment.

Exploiting the immunogenic potential of standard of care radiation or cisplatin therapy in preclinical models of HPV-associated malignancies

BackgroundWhile radiation and chemotherapy are primarily purposed for their cytotoxic effects, a growing body of preclinical and clinical evidence demonstrates an immunogenic potential for these standard therapies. Accordingly, we sought...

TRAIL inhibition by soluble death receptor 5 protects against acute myocardial infarction in rats.

Acute myocardial infarction (AMI) is associated with high morbidity and mortality. An effective therapeutic strategy is to rescue cardiomyocytes from death. Apoptosis is a key reason of cardiomyocyte death that can be prevented. In this study, we investigated the role of TNF-related apoptosis-inducing ligand (TRAIL) in initiating apoptosis by binding to death receptor 5 (DR5), and this procession is inhibited by soluble DR5 (sDR5) in rats after AMI. First, we found that the level of TRAIL in serum was down-regulated in AMI patients. Then, TRAIL and DR5 expression was analysed in the myocardium of rats after AMI, and their expression was up-regulated. sDR5 treatment reduced the myocardial infarct size and the levels of CK-MB and cTn-I in serum. The expression of caspase 3 and PARP is decreased, but the anti-apoptotic factor Bcl-2 was increased in sDR5 treatment rats after AMI. DR5 expression was also analysed after sDR5 treatment and it was down-regulated, and a low level of DR5 expression seemed to be beneficial for the myocardium. Overall, our findings indicated that sDR5 decreases myocardial damage by inhibiting apoptosis in rat after AMI. We expect to observe the potential therapeutic effects of sDR5 on AMI in the future.

Vaccinium bracteatum Thunb Extract Inhibits HSV-1 Infection by Regulating ER Stress and Apoptosis.

Herpes simplex Type 1 (HSV-1) is a neurotropic virus that infects the peripheral and central nervous system. Usually, after primary infection in epithelial cells, HSV-1 migrates retrograde to the peripheral nervous system (PNS), where it establishes a latent infection. HSV-1 can remain latent in the nervous system, and its reactivation in the brain can rarely cause acute HSV-1 encephalitis, often a life-threatening condition, or asymptomatic reactivations that could lead to neuronal damage and ultimately neurodegenerative disorders. Acyclovir and related nucleoside analogs have been used as therapeutic agents for HSV-1 infection, but resistance to the drug can arise, and the protective effect of HSV-1 on brain cells is limited. Therefore, there is an urgent need for research into safe and effective new antiviral agents that can protect brain cells from the damage that is caused by HSV-1 infection. Vaccinium bracteatum Thunb. (VBT) is widely distributed in Korea and China, and has pharmacological actions such as anti-inflammatory, antioxidant, and antidiabetic activity. Studies on the antiviral effect of VBT on HSV-1 infection have not been reported so far. Therefore, we sought to determine the HSV-1 antiviral effect and molecular mechanism of VBT at the cellular level. We confirmed that VBT repressed the VP16 and IE genes in both Vero and SK-N-SH cells. We also found that the generation of HSV-1 virions was inhibited by VBT treatment. VBT inhibited the activities of the HSV-1-induced endoplasmic reticulum (ER) stressors PERK, ATF4, and CHOP. We confirmed that VBT inhibited the activity of apoptosis factors by regulating the expression of death receptor (DR) after HSV-1 infection. As HSV-1 is closely associated with brain diseases, the study of the antiviral drug effects and mechanism of VBT is meaningful. Further studies using animal models of infection will also be performed to determine the potential of VBT as an antiviral agent.

Pharmacological Small Molecules against Prostate Cancer by Enhancing Function of Death Receptor 5.

Death receptor 5 (DR5) is a membrane protein that mediates exogenous apoptosis. Based on its function, it is considered to be a target for the treatment of cancers including prostate cancer. It is encouraging to note that a number of drugs targeting DR5 are now progressing to different stages of clinical trial studies. We collected 38 active compounds that could produce anti-prostate-cancer effects by modulating DR5, 28 of which were natural compounds and 10 of which were synthetic compounds. In addition, 6 clinically used chemotherapeutic agents have also been shown to promote DR5 expression and thus exert apoptosis-inducing effects in prostate cancer cells. These compounds promote the expression of DR5, thereby enhancing its function in inducing apoptosis. When these compounds were used in combination with the natural ligand of DR5, the number of apoptotic cells was significantly increased. These compounds are all promising for development as anti-prostate-cancer drugs, while most of these compounds are currently being evaluated for their anti-prostate-cancer effects at the cellular level and in animal studies. A great deal of more in-depth research is needed to evaluate whether they can be developed as drugs. We collected literature reports on small molecules against prostate cancer through modulation of DR5 to understand the current dynamics in this field and to evaluate the prospects of small molecules against prostate cancer through modulation of DR5.

Reactive oxygen species-dependent upregulation of death receptor, tumor necrosis factor receptor 1, is responsible for theophylline-mediated cytotoxicity in MDA-MB-231 breast cancer cells.

Theophylline, a methylxanthine drug, has been used as a therapy for respiratory diseases. Recently, it has also been shown to have a potential in treating different cancers. Also, it has shown promising results in clinical trials for AML in combination therapy. Subsequently, studies have shown theophylline to kill breast cancer cells but not normal breast cells. Therefore, in this study, we have explored the molecular mechanism underlying the cytotoxic effect of theophylline on breast cancer cells. Theophylline-treated cancer cells were analyzed for the transcript and protein expression of candidate apoptotic genes such as TNFR1, caspase-8, -9, -3 using qPCR and immunoblotting, respectively. Cell viability and apoptosis was measured in the presence or absence of TNFR1 inhibitor, R7050, using AO/EtBr staining and MTT assay, respectively. Similarly, oxidative stress was studied by analyzing ROS in the presence or absence of ROS inhibitor, NAC, using DCFDA assay. Theophylline caused reduced cell viability in cancer but not normal cells. Theophylline-treated breast cancer cells showed increased expression of death receptor, TNFR1, along with elevated levels of active caspase-8, -9 and -3. Inhibition of TNFR1 reduced caspase-dependent apoptosis even in the presence of theophylline. Theophylline further caused increased ROS generation, inhibition of which resulted in reduced TNFR1-mediated apoptosis. Theophylline also increased cathepsin activity, which was reduced on exposure of cells to TNFR1 inhibitor, R7050. We conclude that ROS-mediated activation of TNFR1 is responsible for caspase-3 and cathepsin-dependent cell death in breast cancer cells on exposure to theophylline.

Licochalcone B induces DNA damage, cell cycle arrest, apoptosis, and enhances TRAIL sensitivity in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a highly fatal disease recognized as a growing global health crisis. Traditional Chinese herbal medicines have been used to treat patients with cancer for many years in China. This study investigated the effects of licochalcone B (LCB), a flavonoid compound isolated from the root of Glycyrrhiza uralensis Fisch., on cell proliferation, DNA damage and TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in HCC cells. Our results showed that LCB inhibited cell proliferation and induced DNA damage, cell cycle arrest and apoptosis. Treatment with LCB significantly inhibited the Akt/mTOR pathway and activated endoplasmic reticulum (ER) stress and mitogen-activated protein kinase (MAPK) signaling pathway. Moreover, combined treatment with LCB and TRAIL yielded evident enhancements in the viability reduction and apoptosis. LCB upregulated death receptor 4 (DR4) and death receptor 5 (DR5) protein in a concentration- and time-dependent manner. The knockdown of DR5 significantly suppressed TRAIL-induced cleavage of PARP, which was enhanced by LCB. Treatment with an extracellular-regulated kinase (ERK) inhibitor (PD98059) or c-Jun N-terminal kinase (JNK) inhibitor (SP600125) markedly reduced the LCB-induced upregulation of DR5 expression and attenuated LCB-mediated TRAIL sensitization. In summary, LCB exhibits cytotoxic activity through modulation of the Akt/mTOR, ER stress and MAPK pathways in HCC cells and effectively enhances TRAIL sensitivity through the upregulation of DR5 expression in ERK- and JNK-dependent manner. Combination therapy with LCB and TRAIL may be an alternative treatment strategy for HCC.

Impact of nitric oxide in liver cancer microenvironment

The pro- or antitumoral properties of nitric oxide (NO) are dependent on local concentration, redox state, cellular status, duration of exposure and compartmentalization of NO generation. The intricate network of the tumor microenvironment (TME) is constituted by tumor cells, stromal and immune cells surrounded by active components of extracellular matrix that influence the biological behavior and, consequently, the treatment and prognosis of cancer. The review describes critical events in the crosstalk of cellular and stromal components in the TME, with special emphasis in the impact of NO generation in the regulation of hepatocellular carcinoma (HCC). The increased expression of nitric oxide synthase (NOS) in tumors and NO-end products in plasma have been associated with poor prognosis of cancer. We have assessed the level of the different isoforms of NOS in tumors and its relation to cell proliferation and death markers, and cell death receptor expression in tumors, and apoptotic markers and ligands of TNF-α receptor family in blood from a cohort of patients with HCC from different etiologies submitted to orthotopic liver transplantation (OLT). The high levels of NOS2 in tumors were associated with low plasma concentration of apoptotic markers (M30 and M65), FasL and TNF-α in HCV patients. By contrast, the low levels of NOS2 in tumors from alcohol-derived patients was associated with increased Trail-R1 expression in tumors, and circulating Trail levels compared to observed in plasma from HCV- and alcohol + HCV-derived patients. This study reinforces the association between increased NOS2 expression and potential risk of low patients’ survival in HCC. However, a differential functional relevance of NOS expression in HCC seems to be influenced by etiologies.

Shikonin derivatives cause apoptosis and cell cycle arrest in human chondrosarcoma cells via death receptors and MAPK regulation

BackgroundAlthough chondrosarcoma is the second most common primary malignant bone tumor, treatment options are limited due to its extensive resistance to a chemo- and radiation therapy. Since shikonin has shown potent anticancer activity in various types of cancer cells, it represents a promising compound for the development of a new therapeutic approach.MethodsThe dose-relationships of shikonin and its derivatives acetylshikonin and cyclopropylshikonin on two human chondrosarcoma cell lines were measured using the CellTiter-Glo®. The changes in the cell cycle were presented by flow cytometry. Protein phosphorylation and expression apoptotic markers, MAPKs and their downstream targets were analyzed using western blotting and gene expression were evaluated using RT-qPCR.ResultsChondrosarcoma cells showed a dose-dependent inhibition of cell viability after treatment with shikonin and its derivatives, with the strongest effect for shikonin and IC50 values of 1.3 ± 0.2 µM. Flow cytometric measurements revealed a G2/M arrest of the cells after treatment. Protein and gene expression analysis demonstrated a dose-dependent downregulation of survivin and XIAP, and an upregulation of Noxa, γH2AX, cleaved caspase-8, -9, -3, and -PARP. Furthermore, the expression of various death receptors was modulated. As MAPK signaling pathways play a key role in tumor biology, their phosphorylation pattern and their corresponding downstream gene regulation were analyzed. Treatment with shikonin derivatives caused an inhibition of pSTAT3 and an increase of pAKT and the MAPKs pERK, pJNK, and pp38 in a dose-dependent manner.ConclusionsThese data demonstrated the significant anti-tumorigenic effect of shikonin derivatives in chondrosarcoma and encourage further research.

Indomethacin-induced oxidative stress enhances death receptor 5 signaling and sensitizes tumor cells to adoptive T-cell therapy

BackgroundAdoptive cell therapy (ACT) using genetically modified T cells has evolved into a promising treatment option for patients with cancer. However, even for the best-studied and clinically validated CD19-targeted chimeric...

Abstract 2783: Increased tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression in normal colonic mucosa with imipridone ONC201/TIC10 treatment: A potential biomarker for chemoprevention studies

Abstract Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States and currently the most effective method at reducing risk of death is through screening. Although these strategies have reduced the incidence of CRC, they are invasive, costly, and have low rates of compliance. Chemoprevention aims to prevent or delay the onset of CRC through eradication or prevention of precursor colonic adenomas, ideally with affordable and nontoxic drugs. The imipridone ONC201, which induces apoptosis, in part, through upregulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), is currently undergoing preclinical evaluation as a potential chemopreventive agent. In preclinical models, we found that treatment with ONC201 is capable of increasing TRAIL expression in normal cells and can improve tumor suppression through immune surveillance by the innate immune system. To further assess potential biomarkers of response to ONC201, we evaluated expression of TRAIL and death receptor 5 (DR5), as well as markers related to cellular stemness such as LGR5 in colonic mucosa obtained from mice treated with ONC201 and vehicle controls. In this study, 16-week-old female C57BL/6 mice were administered vehicle or ONC201 50mg/kg (n=11) body weight by oral gavage twice a week for a total of five doses. Both immunohistochemistry and western blotting were used to evaluate differential expression of various potential biomarkers in both fresh frozen and FFPE colonic tissue. Using western blotting we found a significant increase in TRAIL expression in normal colonic mucosa obtained from mice treated with ONC201 as compared to vehicle controls. This finding was further validated using immunohistochemistry. Other markers, such as DR5 appeared unaffected with treatment. As efforts are currently underway to develop a CRC chemoprevention trial using ONC201, TRAIL may represent a biomarker of interest. Further analysis of stemness markers, as well as serum analyses are currently in process and may reveal other potential biomarkers for use in chemoprevention trial development. Citation Format: Alexander G. Raufi, Arielle De La Cruz, Andrew George, Sean Hacking, Venkateshwar Madka, Varun Prabhu, Howard Safran, Lanlan Zhou, Dean Brenner, Chinthalapally V. Rao, Wafik S. El-Deiry. Increased tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression in normal colonic mucosa with imipridone ONC201/TIC10 treatment: A potential biomarker for chemoprevention studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2783.

Abstract 319: Imipridone ONC212 and trametinib combination therapy demonstrates anti-neoplastic effects through immune-mediated mechanisms in pancreatic ductal adenocarcinoma cell lines

Abstract Pancreatic ductal adenocarcinoma (PDAC) is characterized by limited therapeutic options and an extremely high mortality-to-incidence ratio. Chemotherapy remains the primary treatment for metastatic disease and results in only modest improvements in median overall survival, typically with significant toxicity. We previously reported a novel treatment approach with the combination of the imipridone ONC212 and the MEK inhibitor trametinib. This combination demonstrated synergy in multiple KRAS-mutated and KRAS wild-type pancreatic cancer cell lines (BxPC3, PANC1, HPAF-II, AsPC-1). Using Western Blot, we assessed markers of autophagy, including Beclin-1 and LC3B, as well as key second messenger pathway activation/suppression with p-AKT/AKT and p-ERK/ERK. The mechanism of this synergy appears to be heterogeneous, working through autophagy inhibition, MAPK/PI3K pathway perturbation, activation of the integrated stress response and increased cell surface expression of death receptor 5. Further investigation has revealed that ONC212 also appears to synergize with various autophagy inhibitors including hydroxychloroquine and chloroquine. We hypothesized that combining trametinib and ONC212 may also induce cell death in-part through immune cell-mediated mechanisms. To explore this, we performed immune cell co-culture experiments using HPAF-II PDAC cells and natural killer (NK-92) cells at a 1:1 effector-to-target cell ratio with or without ONC212, trametinib, or the combination of the two at different concentrations. We assessed the levels of NK cell mediated-tumor cell death 4, 8, and 24-hours after simultaneous treatment and initiation of co-culture using fluorescent microscopy. Compared to trametinib, ONC212 only treated co-culture showed greater NK cell-mediated tumor cell death. At 24-hours, we also observed an increase in NK cell-mediated killing of PDAC cells with dual treatment as compared to single agent alone or vehicle controls. Importantly, this combination did not appear to have any effect on NK or tumor cell viability. Thus, this combination may represent a potential therapeutic modality for PDAC and may hold promise if combined with immunotherapy. Further in vitro experiments will be conducted to evaluate the effect of ONC212, trametinib, and other autophagy inhibitors on the PDAC tumor microenvironment using a T cell co-culture system. Similarly, in vivo murine studies will also be performed to assess the translational potential of this combination. Citation Format: Alexander G. Raufi, Arielle De La Cruz, Lindsey Carlsen, Kelsey Huntington, Lanlan Zhou, Varun Prabhu, Joshua Allen, Wafik S. El-Deiry. Imipridone ONC212 and trametinib combination therapy demonstrates anti-neoplastic effects through immune-mediated mechanisms in pancreatic ductal adenocarcinoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 319.

A novel tumor-homing TRAIL variant eradicates tumor xenografts of refractory colorectal cancer cells in combination with tumor cell-targeted photodynamic therapy

Multidrug resistance (MDR), which is common in colorectal cancer (CRC), induces high mortality in patients. Due to its robust and selective apoptosis induction in some CRC cells with MDR, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is attractive as a novel tool for CRC therapy. However, TRAIL is limited by its poor tumor-homing ability and inefficient apoptosis induction in CRC cells expressing low levels of death receptor (DR). Here, the tumor-homing RGR peptide (CRGRRST) was fused to TRAIL to produce RGR-TRAIL. Compared with TRAIL, RGR-TRAIL showed greater cell binding and cytotoxicity in CRC cells. In addition, RGR-TRAIL exerted significantly enhanced tumor uptake and growth suppression in mice bearing CRC tumor xenografts. Notably, RGR-TRAIL eradicated all tumor xenografts of DR-overexpressing COLO205 cells. However, TRAIL only showed mild tumor growth suppression under the same conditions, indicating that RGR fusion significantly increased the antitumor effect of TRAIL in DR-overexpressing CRC cells by improving tumor homing. Nevertheless, RGR fusion did not significantly enhance the antitumor effect of TRAIL in HT29 cells expressing low levels of DR. We found that DR expression in HT29 cells was enhanced by epidermal growth factor receptor (EGFR)-targeted photodynamic therapy (PDT). Moreover, both the in vitro and in vivo antitumor effects of RGR-TRAIL were significantly improved by combination with PDT. HT29 tumor xenografts (∼20%) were even eradicated by combination therapy. These results indicate that it is valuable to further evaluate the combination therapy of RGR-TRAIL and tumor-targeted PDT for clinical therapy of CRC with MDR.

SK119, a Novel Shikonin Derivative, Leads to Apoptosis in Melanoma Cell Lines and Exhibits Synergistic Effects with Vemurafenib and Cobimetinib.

Melanoma is a complex and heterogenous disease, displays the deadliest form of skin cancer, and accounts for approx. 80% of all skin cancer deaths. In this study, we reported on the synthesis and pharmacological effects of a novel shikonin derivative (SK119), which is active in a nano-molar range and exhibits several promising in vitro effects in different human melanoma cells. SK119 was synthesized from shikonin as part of our search for novel, promising shikonin derivatives. It was screened against a panel of melanoma and non-tumorigenic cell lines using XTT viability assays. Moreover, we studied its pharmacological effects using apoptosis and Western blot experiments. Finally, it was combined with current clinically used melanoma therapeutics. SK119 exhibited IC50 values in a nano-molar range, induced apoptosis and led to a dose-dependent increase in the expression and protein phosphorylation of HSP27 and HSP90 in WM9 and MUG-Mel 2 cells. Combinatorial treatment, which is highly recommended in melanoma, revealed the synergistic effects of SK119 with vemurafenib and cobimetinib. SK119 treatment changed the expression levels of apoptosis genes and death receptor expression and exhibited synergistic effects with vemurafenib and cobimetinib in human melanoma cells. Further research indicates a promising potential in melanoma therapy.

Sometimes simple is not best: The complex γδ T cell interaction with tumour needs depth

Sometimes simple is not best: The complex γδ T cell interaction with tumour needs depth

NSAIDs-induced oxidative stress sensitizes tumor cells to T cell cytotoxicity through the TRAIL-DR5 axis

Abstract Adoptive T cell therapy (ACT) has shown promising therapeutic outcomes in patients with hematological malignancies. However, the success of ACT is limited to a small fraction of treated patients. Hence, developing new strategies to enhance the potency of ACT are urgently needed for better therapeutic outcomes. Our previous study demonstrated that inducing oxidative stress in tumor cells is critically involved in tumor rejection by ACT. In the current study, we report that indomethacin, a prototypical non-steroidal anti-inflammatory drug (NSAID), can intensify ROS in tumor cells and sensitize them to ACT. Mechanistically, our data indicate that indomethacin treatment leads to enhanced expression of death receptor 5 (DR5) in tumor cells, rendering them more susceptible to TNF-related apoptosis-inducing ligand (TRAIL)-induced cell death. We found that tumor-specific T cells upregulated TRAIL expression upon adoptive transfer. Using genetic-based approaches, we showed that DR5-deficient tumor cells were unresponsive to the beneficial effect of indomethacin, while overexpressing TRAIL in donor T cells led to further improvement in mouse survival. Collectively, our study demonstrates that the pro-oxidative feature of selected NSAIDs can be exploited to augment the efficacy of T cell therapy. Our findings provide a strong rationale for targeting tumor redox to achieve more effective tumor destruction through the combination of pro-oxidants and ACT.

Investigating the susceptibility of treatment-resistant oesophageal tumours to natural killer cell-mediated responses

The majority of oesophageal adenocarcinoma (OAC) patients do not respond to multimodal treatment regimens and face dismal survival rates. Natural killer (NK) cells are crucial anti-tumour immune cells, and this study investigated the susceptibility of treatment-resistant OAC cells to these potent tumour killers. Natural killer receptor (NKR) ligand expression by OE33CisP (cisplatin-sensitive) and OE33CisR (cisplatin-resistant) cells was investigated. The immunomodulatory effects of OE33CisP and OE33CisR cells on NK cell phenotype and function were assessed. Finally, the impact of chemotherapy regimens on NKR ligand shedding was examined. Our data revealed significantly less surface expression of activating ligands B7-H6, MICA/B, ULBP-3 and activating/inhibitory ligands PVRL-1 and PVRL-4 by OE33CisR cells, compared to OE33CisP cells. Co-culture with OE33CisR cells reduced the frequencies of NKp30+ and NKp46+ NK cells and increased frequencies of TIGIT+, FasL+ and TRAIL+ NK cells. Frequencies of IFN-γ-producing NK cells increased while frequencies of TIM-3+ NK cells decreased after culture with OE33CisP and OE33CisR cells. Frequencies of circulating NKp30+ NK cells were significantly lower in OAC patients with the poorest treatment response and in patients who received FLOT chemotherapy, while B7-H6 shedding by OAC tumour cells was induced by FLOT. Overall, OE33CisR cells express less activating NKR ligands than OE33CisP cells and have differential effects on NKR expression by NK cells. However, neither cell line significantly dampened NK cell cytokine production, death receptor expression or degranulation. In addition, our data indicate that FLOT chemotherapy may promote B7-H6 shedding and immune evasion with detrimental consequences in OAC patients.

Enhanced expression of death receptor 5 is responsible for increased cytotoxicity of theophylline in combination with recombinant human TRAIL in MDA-MB-231 breast cancer cells.

Theophylline has been reported to induce cytotoxicity and cell cycle arrest in cancer cells. On the other hand, TRAIL, a secretory ligand, is known for its unique ability to induce cell death only in tumor cells. In the present study, we elucidated the mechanism behind the cytotoxic effect of theophylline in combination with recombinant human TRAIL (rhTRAIL) on cancer cell line MDA-MB-231. Cytotoxicity of theophylline in combination with TRAIL was measured via trypan blue assay and MTT assay. Protein levels were assessed using Western hybridization. Reactive oxygen species (ROS) levels were measured using 2',7'-dichlorofluorescin diacetate and mitochondrial membrane potential (MMP) assay was conducted using tetramethylrhodamine, ethyl ester. We observed theophylline in combination with rhTRAIL to be significantly cytotoxic to the cancer cells in comparison to theophylline and rhTRAIL alone. Next, western hybridization showed combination treatment to upregulate cleaved form of caspase-8, 9 and 3, in comparison to the cells treated with rhTRAIL and theophylline alone. Theophylline in combination also increased the levels of ROS and reduced MMP. Interestingly, combination treatment increased the protein level of death receptor 5 (DR5), sensitizing the cells towards TRAIL-induced apoptosis. Theophylline in combination with TRAIL significantly increases cytotoxicity in the MDA-MB-231 breast cancer cell line when compared to theophylline and rhTRAIL alone via upregulation of DR5 levels.