ABSTRACT
Our team has previously reported a series of quinazoline-based lapatinib hybrids as potent kinase-targeting anticancer agents. Among them, AF8c showed a relatively safe profile in colorectal cancer (CRC) cells. In this study, we delineate a novel anticancer activity of AF8c in CRC cells. AF8c mediated p53-dependent apoptosis of CRC cells via the generation of endoplasmic reticulum (ER) stress and reactive oxygen species (ROS), as well as activation of nuclear respiratory factor 2 alpha subunit (Nrf2) and death receptor 5 (DR5), among others. The silencing of DR5 attenuated the expression levels of Nrf2 and partially inhibited AF8c-induced apoptosis. Additionally, upregulation of Nrf2 by AF8c evoked apoptosis through a decrease in antioxidant levels. Treatment of a CRC mice model with AF8c also resulted in the upregulation of DR5, Nrf2, and CHOP proteins, subsequently leading to a significant decrease in tumor burden. In comparison with lapatinib, AF8c showed higher cellular antiproliferative activity at the tested concentrations in CRC cells and synergized TRAIL effects in CRC cells. Overall, our results suggest that AF8c-induced apoptosis may be associated with DR5/Nrf2 activation through ER stress and ROS generation in CRC cells. These findings indicate that AF8c represents a promising polypharmacological molecule for the treatment of human CRC.
ABSTRACT
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is known to behave as an attractive anti-cancer agent in various cancers. Despite its promise TRAIL has limitations such as short half-life and rapid development of resistance. In this regard, approaches to sensitizers of TRAIL that can overcome the limitations of TRAIL are necessary. However, the molecular targets and mechanisms underlying sensitization to TRAIL-induced apoptosis are not fully understood. Here, we propose that reactive oxygen species modulator-1 (Romo1) as an attractive sensitizer of TRAIL. Romo1 is a mitochondrial inner membrane channel protein that controls reactive oxygen species (ROS) production, and its expression is highly upregulated in various cancers, including colorectal cancer. In the present study, we demonstrated that Romo1 inhibition significantly increased TRAIL-induced apoptosis of colorectal cancer cells, but not of normal colon cells. The combined effect of TRAIL and Romo1 inhibition was correlated with the activation of mitochondrial apoptosis pathways. Romo1 silencing elevated the protein levels of BCL-2-associated X protein (Bax) by downregulating the ubiquitin proteasome system (UPS). Romo1 inhibition downregulated the interaction between Bax and Parkin. Furthermore, Romo1 knockdown triggered the mitochondrial dysfunction and ROS generation. We validated the effect of combination in tumor xenograft model in vivo. In conclusion, our study demonstrates that Romo1 inhibition induces TRAIL-mediated apoptosis by identifying the novel mechanism associated with the Bax/Parkin interaction. We suggest that targeting of Romo1 is essential for the treatment of colorectal cancer and may be a new therapeutic approach in the future and contribute to the drug discovery.
ABSTRACT
Oxaliplatin is used for treatment in combination with many drugs. However, the survival rate is still low due to side effects and drug resistance. Therefore, the combination with natural products was required for increasing efficacy and reducing side effects. Genipin, a natural product derived from the Gardenia jasminoides, associated with anti-angiogenic, anti-proliferative, hypertension, inflammatory, and the Hedgehog pathway. It is not known that genipin increases the therapeutic effect of oxaliplatin in gastric cancer. In this study, we found that genipin sensitizes oxaliplatin-induced apoptosis for the first time using colony forming assay, FACS analysis, and western blotting in gastric cancer. Additionally, genipin induced p53 expression in AGS, MKN45, and MKN28 cells. Also, genipin induced autophagy and LC3 expression. Knockdown of LC3 decreased cell death enhanced by the combination of oxaliplatin and genipin. In summary, we showed that genipin increases the oxaliplatin-induced cell death via p53-DRAM autophagy. Based on this, we suggest that genipin is a sensitizer of oxaliplatin.
ABSTRACT
BACKGROUND AND AIMS: Colitis-associated cancer (CAC) is one of the most serious complications in patients with inflammatory bowel disease. Sphingosine kinase 1 (Sphk1) is a key enzyme in the sphingolipid pathway and has oncogene potential for inducing both initiation and progression of tumors. The aim of this work is to characterize the role of epithelial Sphk1 in mouse colitis and CAC models. METHODS: We investigated the roles of Sphk1 in CAC by conditional deletion of Sphk1 in intestinal epithelial cells (IECs). RESULTS: CAC was induced in both Sphk1ΔIEC/ApcMin/+ and Sphk1IEC/ApcMin/+ mice by administration of 2% dextran sodium sulfate (DSS) for 7 days. Genetic deletion of Sphk1 significantly reduced the number and size of tumors in ApcMin/+ mice. Histologic grade was more severe in Sphk1ΔIEC/ApcMin/+ mice compared with Sphk1IEC/ApcMin/+ mice (invasive carcinoma, 71% versus 13%, p < 0.05). Deletion of Sphk1 decreased mucosal proliferation and inhibited STAT3 activation and genetic expression of cyclin D1 and cMyc in tumor cells. Conditional deletion of Sphk1 using CRISPR-Cas9 in HCT 116 cells inhibited interleukin (IL)-6-mediated STAT3 activation. CONCLUSIONS: Epithelial conditional deletion of Sphk1 inhibits CAC in ApcMin/+-DSS models in mice by inhibiting STAT3 activation and its target signaling pathways.
Subject(s)
Carcinoma/etiology , Colonic Neoplasms/etiology , Phosphotransferases (Alcohol Group Acceptor)/physiology , STAT3 Transcription Factor/metabolism , Animals , Carcinogenesis , Colitis/complications , Dextran Sulfate , Epithelial Cells/metabolism , HCT116 Cells , Humans , Mice, KnockoutABSTRACT
Disabled tumor suppressor genes and hyperactive oncogenes greatly contribute to cell fates during cancer development because of their genetic alterations such as somatic mutations. However, little is known about how tumor suppressor genes react to diverse oncogenes during tumor progression. Our previous study showed that RUNX3 inhibits invasiveness by preventing vascular endothelial growth factor secretion and suppressed endothelial cell growth and tube formation in colorectal cancer (CRC). Hedgehog signaling is crucial for the physiological maintenance and self-renewal of stem cells, and its deregulation is responsible for their tumor development. The mechanisms that inhibit this pathway during proliferation remain poorly understood. Here, we found that the tumor suppressor RUNX3 modulates tumorigenesis in response to cancer cells induced by inhibiting oncogene GLI1 ubiquitination. Moreover, we demonstrated that RUNX3 and GLI1 expression were inversely correlated in CRC cells and tissues. We observed a direct interaction between RUNX3 and GLI1, promoting ubiquitination of GLI1 at the intracellular level. Increased ubiquitination of GLI1 was induced by the E3 ligase ß-TrCP. This novel RUNX3-dependent regulatory loop may limit the extent and duration of Hedgehog signaling during extension of the tumor initiation capacity. On the basis of our results, identification of agents that induce RUNX3 may be useful for developing new and effective therapies for CRC.
Subject(s)
Colonic Neoplasms/metabolism , Core Binding Factor Alpha 3 Subunit/metabolism , Hedgehog Proteins/metabolism , Animals , Apoptosis , Cell Cycle , Cell Proliferation , Colonic Neoplasms/pathology , Core Binding Factor Alpha 3 Subunit/genetics , Female , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Signal Transduction , Tumor Cells, CulturedABSTRACT
Hypoxia, or the deficiency of oxygen, in solid tumors is majorly responsible for the progression of cancer and remains unaffected by chemotherapy, but still requires definitive definition of the hypoxia signaling. Hypoxia disrupts the complete folding of mitochondrial proteins, leading to several diseases. The present study confirms that hypoxia activates the Hedgehog pathway in colorectal cancer (CRC), considering its role in cancer epithelial to mesenchymal transition, migration, and invasion. The activity of hypoxia-mediated Gli-1, a Hedgehog signaling factor in hypoxia, was confirmed by in vitro western blotting, immunofluorescence staining, wound-healing assay, and matrigel invasion assay, as well as by in vivo xenograft models (n = 5 per group). The Gli-1 mechanism in hypoxia was analyzed via mass spectrometry. Hypoxia enhanced the interaction of Gli-1 and T-complex protein 1 subunit beta (CCT2), as observed in the mass spectrometric analysis. We observed that reduction in CCT2 inhibits tumor induction by Gli-1. Ubiquitination-mediated Gli-1 degradation by ß-TrCP occurs during incomplete folding of Gli-1 in hypoxia. The human CRC tissues revealed greater CCT2 expression than did the normal colon tissues, indicating that higher CCT2 expression in tumor tissues from CRC patients reduced their survival rate. Moreover, we suggest that CCT2 correlates with Gli-1 expression and is an important determinant of survival in the CRC patients. The results reveal that CCT2 can regulate the folding of Gli-1 in relation to hypoxia in CRC.
Subject(s)
Chaperonin Containing TCP-1/genetics , Colorectal Neoplasms/genetics , Tumor Hypoxia/genetics , Zinc Finger Protein GLI1/genetics , Animals , Cell Movement/drug effects , Cell Proliferation/drug effects , Chaperonin Containing TCP-1/chemistry , Colorectal Neoplasms/pathology , Female , Gene Expression Regulation, Neoplastic/drug effects , HCT116 Cells , Hedgehog Proteins/genetics , Heterografts , Humans , Male , Mice , Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/pathology , Protein Folding , Proteolysis/drug effects , Signal Transduction/genetics , Survival Rate , Ubiquitination/genetics , Zinc Finger Protein GLI1/chemistry , beta-Transducin Repeat-Containing Proteins/pharmacologyABSTRACT
According to recent studies, Cannabidiol (CBD), one of the main components of Cannabis sativa, has anticancer effects in several cancers. However, the exact mechanism of CBD action is not currently understood. Here, CBD promoted cell death in gastric cancer. We suggest that CBD induced apoptosis by suppressing X-linked inhibitor apoptosis (XIAP), a member of the IAP protein family. CBD reduced XIAP protein levels while increasing ubiquitination of XIAP. The expression of Smac, a known inhibitor of XIAP, was found to be elevated during CBD treatment. Moreover, CBD treatment increased the interaction between XIAP and Smac by increasing Smac release from mitochondria to the cytosol. CBD has also been shown to affect mitochondrial dysfunction. Taken together, these results suggest that CBD may have potential as a new therapeutic target in gastric cancer.
Subject(s)
Apoptosis Regulatory Proteins/metabolism , Apoptosis , Biomarkers, Tumor/metabolism , Cannabidiol/pharmacology , Gene Expression Regulation, Neoplastic/drug effects , Mitochondrial Proteins/metabolism , Stomach Neoplasms/pathology , X-Linked Inhibitor of Apoptosis Protein/metabolism , Animals , Apoptosis Regulatory Proteins/genetics , Biomarkers, Tumor/genetics , Cell Proliferation , Female , Humans , Mice , Mice, Inbred BALB C , Mice, Nude , Mitochondrial Proteins/genetics , Neoplasm Invasiveness , Stomach Neoplasms/genetics , Stomach Neoplasms/metabolism , Tumor Cells, Cultured , X-Linked Inhibitor of Apoptosis Protein/genetics , Xenograft Model Antitumor AssaysABSTRACT
Despite the importance of radiation therapy, there are few radiation-related markers available for use in clinical practice. A larger catalog of such biomarkers is required to help clinicians decide when radiotherapy should be replaced with a patient-specific treatment. Arachidonate 15-lipoxygenase (15-LOX-1) enzyme is involved in polyunsaturated fatty acid metabolism. When colorectal cancer (CRC) cells were exposed to radiation, 15-LOX-1 was upregulated. To verify whether 15-LOX-1 protects against or induces DNA damage, we irradiated sh15-LOX-1 stable cells. We found that low 15-LOX-1 is correlated with radioresistance in CRC cells. These data suggest that the presence of 15-LOX-1 can be used as a marker for radiation-induced DNA damage. Consistent with this observation, gene-set-enrichment analysis based on microarray experiments showed that UV_RESPONSE was decreased in sh15-LOX-1 cells compared to shCon cells. Moreover, we discovered that the expression of the histone H2A variant macroH2A2 was sevenfold lower in sh15-LOX-1 cells. Overall, our findings present mechanistic evidence that macroH2A2 is transcriptionally regulated by 15-LOX-1 and suppresses the DNA damage response in irradiated cells by delaying H2AX activation.
ABSTRACT
BACKGROUND: Although the anticancer activity of Korean Red Ginseng (KRG) has been known in various cancers, the mechanism of KRG-induced apoptosis is unknown in colorectal cancer (CRC). In our study, we examined whether KRG induces apoptosis in CRC cells. METHODS: In the cell viability assay, the concentration of the appropriate KRG extracts was fixed at 2.5 mg/mL in numerous CRC cells. This fixed concentration was in other experiments, and it was confirmed that the KRG extracts induce apoptosis in CRC cells. RESULTS: We found that KRG induced Noxa activation and apoptosis and increased endoplasmic reticulum stress via reactive oxygen species production. This indicated that KRG efficiently enhanced cell death in CRC cells. CONCLUSION: Our results show that KRG can be used as a possible anticancer drug for patients with CRC.
Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Colorectal Neoplasms/drug therapy , Panax/chemistry , Plant Extracts/pharmacology , Proto-Oncogene Proteins c-bcl-2/metabolism , Antineoplastic Agents, Phytogenic/isolation & purification , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Endoplasmic Reticulum Stress/drug effects , Gene Expression Regulation, Neoplastic , HCT116 Cells , HT29 Cells , Humans , Plant Extracts/isolation & purification , Proto-Oncogene Proteins c-bcl-2/genetics , Reactive Oxygen Species/metabolism , Signal TransductionABSTRACT
BACKGROUND: Genipin is a compound derived from gardenia fruit extract. Although Genipin has anti-tumor effects in various cancers, its effect and mechanism in gastric cancer remain unclear. Here, we investigated the relationship between the anticancer effect of Genipin and signal transducer and activator of transcription (Stat3)/myeloid cell leukemia-1 (Mcl-1) in human gastric cancers. METHODS: MTT assays were performed to determine the cell viability of gastric cancer and gastric epithelial cell lines (AGS, MKN45, SNU638, MKN74, HFE-145). A TUNEL assay and Western blotting were carried out to investigate apoptosis. Stat3 activity was measured by proteome profiler phospho kinase array, immunofluorescence and immunoblotting. Mitochondria function was monitored with an XF24 analyzer and by flow cytometry, confocal microscopy using fluorescent probes for general mitochondrial membrane potential (MMP). RESULTS: Genipin induced apoptosis in gastric cancer cells, including AGS and MKN45 cells. Genipin also reduced Mcl-1 mRNA and protein levels. Furthermore, we found that phosphorylation of Stat3 is regulated by Genipin. Additionally, the protein level of phospho Janus kinase 2 (JAK2) was decreased by Genipin treatment, indicating that the Stat3/JAK2/Mcl-1 pathway is suppressed by Genipin treatment in gastric cancer cells. Mcl-1 is closely related to mitochondrial function. These findings suggest that Genipin contributes to the collapse of mitochondrial functions like MMP. CONCLUSIONS: Genipin induced apoptosis by suppressing the Stat3/Mcl-1 pathway and led to mitochondrial dysfunction. Our results reveal a novel mechanism for the anti-cancer effect of Genipin in gastric cancer.
Subject(s)
Apoptosis/drug effects , Down-Regulation , Iridoids/pharmacology , Mitochondria/metabolism , Myeloid Cell Leukemia Sequence 1 Protein/metabolism , STAT3 Transcription Factor/metabolism , Stomach Neoplasms/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Gene Knockdown Techniques , Humans , Janus Kinase 2/metabolism , Membrane Potential, Mitochondrial/drug effects , Myeloid Cell Leukemia Sequence 1 Protein/genetics , Phosphorylation/drug effects , Signal Transduction/drug effects , Stomach Neoplasms/pathology , TransfectionABSTRACT
Oxaliplatin is an anticancer drug administered to colorectal cancer (CRC) patients in combination with 5-fluorouracil and antibodies (bevacizumab and cetuximab), thereby significantly improving the survival rate of CRC. However, due to various side effects associated with the above treatment strategy, the need for combinatorial therapeutic strategies has emerged. Based on the demand for new combinatorial therapies and the known antitumor effects of the omega-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), we investigated the Oxaliplatin and DHA combination for its effect. Our results indicated that DHA further enhanced Oxaliplatin-induced cell viability and autophagic cell death, in vitro and in vivo. Oxaliplatin and DHA also increased the expression of Sestrin 2 (SESN2) and endoplasmic reticulum (ER) stress related C/EBP homologous protein (CHOP). Additionally, treatment with Oxaliplatin and DHA enhanced the binding of CHOP to the promotor region of SESN2, increasing SESN2 expression. These results suggested that DHA enhanced Oxaliplatin-induced reduction in cell viability and increase in autophagy via activating SESN2 and increasing ER stress. Thus, SESN2 may be an effective preclinical target for CRC treatment.
ABSTRACT
Although oxaliplatin is an effective chemotherapeutic drug for colorectal cancer (CRC) treatment, patients often develop resistance to it. Therefore, a new strategy for CRC treatment is needed. The purpose of this study was to determine the effect of cannabidiol (CBD), one of the components of the cannabis plant, in overcoming oxaliplatin resistance in CRC cells. We established oxaliplatin-resistant cell lines, DLD-1 R and colo205 R, in CRC DLD-1 and colo205 cells. Autophagic cell death was induced when oxaliplatin-resistant cells were treated with both oxaliplatin and CBD. Additionally, phosphorylation of nitric oxide synthase 3 (NOS3) was increased in oxaliplatin-resistant cells compared to that in parent cells. Combined treatment with oxaliplatin and CBD reduced phospho-NOS3 levels and nitric oxide (NO) production and resulted in the production of reactive oxygen species (ROS) by reducing the levels of superoxide dismutase 2, an antioxidant present in the mitochondria, causing mitochondrial dysfunction. Taken together, these results suggest that elevated phosphorylation of NOS3 is essential for oxaliplatin resistance. The combination of oxaliplatin and CBD decreased NOS3 phosphorylation, which resulted in autophagy, by inducing the overproduction of ROS through mitochondrial dysfunction, thus overcoming oxaliplatin resistance.
ABSTRACT
A major problem of colorectal cancer (CRC) targeted therapies is relapse caused by drug resistance. In most cases of CRC, patients develop resistance to anticancer drugs. Cetuximab does not show many of the side effects of other anticancer drugs and improves the survival of patients with metastatic CRC. However, the molecular mechanism of cetuximab resistance is not fully understood. Methods: EPHB3-mediated cetuximab resistance was confirmed by in vitro western blotting, colony-forming assays, WST-1 colorimetric assay, and in vivo xenograft models (n = 7 per group). RNA-seq analysis and receptor tyrosine kinase assays were performed to identify the cetuximab resistance mechanism of EPHB3. All statistical tests were two-sided. Results: The expression of EFNB3, which upregulates the EPHB3 receptor, was shown to be increased via microarray analysis. When resistance to cetuximab was acquired, EPHB3 protein levels increased. Hedgehog signaling, cancer stemness, and epithelial-mesenchymal transition signaling proteins were also increased in the cetuximab-resistant human colon cancer cell line SW48R. Despite cells acquiring resistance to cetuximab, STAT3 was still responsive to EGF and cetuximab treatment. Moreover, inhibition of EPHB3 was associated with decreased STAT3 activity. Co-immunoprecipitation confirmed that EGFR and EPHB3 bind to each other and this binding increases upon resistance acquisition, suggesting that STAT3 is activated by the binding between EGFR and EPHB3. Protein levels of GLI-1, SOX2, and Vimentin, which are affected by STAT3, also increased. Similar results were obtained in samples from patients with CRC. Conclusion: EPHB3 expression is associated with anticancer drug resistance.
Subject(s)
Colorectal Neoplasms/metabolism , Drug Resistance, Neoplasm , Hedgehog Proteins/metabolism , Receptor, EphB3/metabolism , Signal Transduction , Animals , Antineoplastic Agents/therapeutic use , Cetuximab/therapeutic use , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , ErbB Receptors/genetics , ErbB Receptors/metabolism , Female , HCT116 Cells , HT29 Cells , Hedgehog Proteins/genetics , Humans , Mice , Mice, Inbred BALB C , Mice, Nude , Receptor, EphB3/genetics , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolism , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism , Vimentin/genetics , Vimentin/metabolism , Zinc Finger Protein GLI1/genetics , Zinc Finger Protein GLI1/metabolismABSTRACT
Natural products have shown great promise in sensitizing cells to TNF-related apoptosis-inducing ligand (TRAIL) therapy. Sea cucumber (SC) extracts possess antitumor activity, and hence their potential to sensitize colorectal cancer (CRC) cells to TRAIL therapy was evaluated. This study used Western blotting to evaluate the combination effects of SC and TRAIL in CRC, and determined the molecular mechanism underlying these effects. SC fractions and TRAIL alone did not affect apoptosis; however, combined treatment dramatically induced the apoptosis of CRC cells, but not of normal colon cells. Combined treatment induced the expression of apoptotic proteins (poly (ADP-ribose) polymerase (PARP), caspase 3, and 8), and this effect was markedly inhibited by the ubiquitination of X-linked inhibitor of apoptosis protein (XIAP). SC did not affect the mRNA levels, but it increased proteasomal degradation and ubiquitination of the XIAP protein. Furthermore, SC induced reactive oxygen species (ROS) production, thereby activating c-Jun N-terminal kinase (JNK) and endoplasmic reticulum (ER) stress-related apoptotic pathways in CRC. Altogether, our results demonstrate that the SC F2 fraction may sensitize CRC cells to TRAIL-induced apoptosis through XIAP ubiquitination and ER stress.
Subject(s)
Biological Products/pharmacology , Colon/drug effects , Colorectal Neoplasms/metabolism , Endoplasmic Reticulum Stress/drug effects , Stichopus/chemistry , TNF-Related Apoptosis-Inducing Ligand/pharmacology , X-Linked Inhibitor of Apoptosis Protein/metabolism , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Antineoplastic Combined Chemotherapy Protocols , Apoptosis , Biological Products/therapeutic use , Caspase 3/metabolism , Caspase 8/metabolism , Cell Line, Tumor , Colon/metabolism , Colon/pathology , Colorectal Neoplasms/drug therapy , Drug Synergism , Humans , JNK Mitogen-Activated Protein Kinases/metabolism , Poly(ADP-ribose) Polymerases/metabolism , Reactive Oxygen Species/metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism , Sea Cucumbers , TNF-Related Apoptosis-Inducing Ligand/therapeutic use , Tumor Necrosis Factor-alpha/metabolism , UbiquitinationABSTRACT
Cannabidiol, a major non-psychotomimetic compound derived from Cannabis sativa, is a potential therapeutic agent for a variety of diseases such as inflammatory diseases, chronic neurodegenerative diseases, and cancers. Here, we found that the combination of cannabidiol and TNF-related apoptosis-inducing ligand (TRAIL) produces synergistic antitumor effects in vitro. However, this synergistic effect was not observed in normal colonic cells. The levels of ER stress-related proteins, including C/EBP homologous protein (CHOP) and phosphorylated protein kinase RNA-like ER kinase (PERK) were increased in treatment of cannabidiol. Cannabidiol enhanced significantly DR5 expression by ER stress. Knockdown of DR5 decreased the combined effect of cannabidiol and TRAIL. Additionally, the combination of TRAIL and cannabidiol decreased tumor growth in xenograft models. Our studies demonstrate that cannabidiol enhances TRAIL-induced apoptosis by upregulating DR5 and suggests that cannabidiol is a novel agent for increasing sensitivity to TRAIL.
ABSTRACT
Despite an increase in the survival rate of patients with cancer owing to the use of current chemotherapeutic agents, adverse effects of cancer therapies remain a concern. Combination therapies have been developed to increase efficacy, reduce adverse effects, and overcome drug resistance. Genipin is a natural product derived from Gardenia jasminoides, which has been associated with anti-inflammatory, anti-angiogenic, and anti-proliferative effects; hypertension; and anti-ischemic brain injuries. However, the enhancement of oxaliplatin sensitivity by genipin remains unexplored. Our study showed that a combination of genipin and oxaliplatin exerts synergistic antitumor effects in vitro and in vivo in colorectal cancer cell lines through the reactive oxygen species (ROS)/endoplasmic reticulum (ER) stress/BIM pathway. Importantly, the combination did not affect normal colon cells. BIM knockdown markedly inhibited apoptosis induced by the combination. In addition, genipin induced ROS by inhibiting superoxide dismutase 3 activity. These findings suggest that genipin may be a novel agent for increasing the sensitivity of oxaliplatin against colorectal cancer. The combination of oxaliplatin and genipin hold significant therapeutic potential with minimal adverse effects.
Subject(s)
Antineoplastic Agents/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Colorectal Neoplasms/drug therapy , Iridoids/therapeutic use , Oxaliplatin/therapeutic use , Plant Extracts/therapeutic use , Animals , Antineoplastic Agents/adverse effects , Apoptosis/drug effects , Bcl-2-Like Protein 11/genetics , Bcl-2-Like Protein 11/metabolism , Colorectal Neoplasms/metabolism , Drug Resistance, Neoplasm/drug effects , Drug Synergism , Endoplasmic Reticulum Stress/drug effects , Female , Gardenia/chemistry , Gene Knockdown Techniques , HCT116 Cells , Humans , Iridoids/adverse effects , Iridoids/pharmacology , Mice , Mice, Inbred BALB C , Mice, Nude , Oxaliplatin/adverse effects , Plant Extracts/adverse effects , Reactive Oxygen Species/metabolism , Superoxide Dismutase/antagonists & inhibitors , Superoxide Dismutase/metabolism , Transfection , Tumor Burden/drug effects , Xenograft Model Antitumor AssaysABSTRACT
RUNX3 is frequently inactivated by DNA hypermethylation in numerous cancers. Here, we show that RUNX3 has an important role in modulating apoptosis in immediate response to tumor necrosis factor-related apoptosis-including ligand (TRAIL). Importantly, no combined effect of TRAIL and RUNX3 was observed in non-cancerous cells. We investigated the expression of the death receptors (DRs) DR4 and DR5, which are related to TRAIL resistance. Overexpression of RUNX3 increased DR5 expression via induction of the reactive oxygen species (ROS)-endoplasmic reticulum (ER) stress-effector CHOP. Reduction of DR5 markedly decreased apoptosis enhanced by the combined therapy of TRAIL and RUNX3. Interestingly, RUNX3 induced reactive oxygen species production by inhibiting SOD3 transcription via binding to the Superoxide dismutase 3 (SOD3) promoter. Additionally, the combined effect of TRAIL and RUNX3 decreased tumor growth in xenograft models. Our results demonstrate a direct role for RUNX3 in TRAIL-induced apoptosis via activation of DR5 and provide further support for RUNX3 as an anti-tumor.
Subject(s)
Colorectal Neoplasms/pathology , Core Binding Factor Alpha 3 Subunit/metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism , TNF-Related Apoptosis-Inducing Ligand/metabolism , Apoptosis/physiology , Colorectal Neoplasms/genetics , Core Binding Factor Alpha 3 Subunit/genetics , Endoplasmic Reticulum Stress , Female , HT29 Cells , Humans , Male , Reactive Oxygen Species/metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics , Superoxide Dismutase/metabolism , TNF-Related Apoptosis-Inducing Ligand/genetics , Transcription Factor CHOP/metabolism , Up-RegulationABSTRACT
Cannabidiol (CBD), one of the compounds present in the marijuana plant, has anti-tumor properties, but its mechanism is not well known. This study aimed to evaluate the apoptotic action of CBD in colorectal cancer (CRC) cells, and focused on its effects on the novel pro-apoptotic Noxa-reactive oxygen species (ROS) signaling pathway. CBD experiments were performed using the CRC cell lines HCT116 and DLD-1. CBD induced apoptosis by regulating many pro- and anti-apoptotic proteins, of which Noxa showed significantly higher expression. To understand the relationship between Noxa and CBD-induced apoptosis, Noxa levels were downregulated using siRNA, and the expression of apoptosis markers decreased. After ROS production was blocked, the level of Noxa also decreased, suggesting that ROS is involved in the regulation of Noxa, which along with ROS is a well-known pro-apoptotic signaling agents. As a result, CBD induced apoptosis in a Noxa-and-ROS-dependent manner. Taken together, the results obtained in this study re-demonstrated the effects of CBD treatment in vivo, thus confirming its role as a novel, reliable anticancer drug.
Subject(s)
Apoptosis/drug effects , Cannabidiol/pharmacology , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Antineoplastic Agents/pharmacology , Apoptosis Regulatory Proteins/metabolism , Cell Line, Tumor , HCT116 Cells , Humans , Reactive Oxygen Species/metabolism , Signal Transduction/drug effectsABSTRACT
Imatinib is a powerful tyrosine kinase inhibitor that specifically targets BCRABL, cKIT, and PDGFR kinases, and is used in the treatment of chronic myelogenous leukemia, gastrointestinal stromal tumors, and other types of cancers. However, the possible anticancer effects of imatinib in gastric cancer have not yet been explored. The present study evaluated the in vitro effects of imatinib on gastric cancer cells and determined the molecular mechanism underlying these effects. We determined that imatinib induced mitochondriamediated apoptosis of gastric cancer cells by involving endoplasmic reticulum (ER) stressassociated activation of cJun NH2terminal kinase (JNK). We also found that imatinib suppressed cell proliferation in a time and dosedependent manner. Cell cycle analysis revealed that imatinibtreated AGS cells were arrested in the G2/M phase of the cell cycle. Moreover, imatinibtreated cells exhibited increased levels of phosphorylated JNK, and of the transcription factor C/EBP homologous protein, an ER stressassociated apoptotic molecule. Results of cell viability assays revealed that treatment with a combination of imatinib and chemotherapy agents irinotecan or 5Fu synergistically inhibited cell growth, compared with treatment with any of these drugs alone. These data indicated that imatinib exerted cytotoxic effects on gastric cancer cells by inducing apoptosis mediated by reactive oxygen species generation and ER stressassociated JNK activation. Furthermore, we revealed that imatinib induced the apoptosis of gastric cancer cells by inhibiting plateletderived growth factor receptor signaling. Collectively, our results strongly support the use of imatinib in the treatment of treating gastric cancer.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Apoptosis/drug effects , Endoplasmic Reticulum Stress/drug effects , Imatinib Mesylate/pharmacology , Protein Kinase Inhibitors/pharmacology , Stomach Neoplasms/drug therapy , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Cell Line, Tumor , Cell Proliferation , Drug Synergism , Endoribonucleases/metabolism , Fluorouracil/pharmacology , Fluorouracil/therapeutic use , Humans , Imatinib Mesylate/therapeutic use , Irinotecan/pharmacology , Irinotecan/therapeutic use , JNK Mitogen-Activated Protein Kinases/metabolism , Protein Kinase Inhibitors/therapeutic use , Protein Serine-Threonine Kinases/metabolism , Reactive Oxygen Species/metabolism , Receptors, Platelet-Derived Growth Factor/metabolism , Signal Transduction/drug effects , Stomach Neoplasms/pathology , Transcription Factor CHOP/metabolismABSTRACT
This study demonstrates that combined treatment with subtoxic doses of Codium extracts (CE), a flavonoid found in many fruits and vegetables, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), induces apoptosis in TRAIL-resistant colorectal cancer (CRC) cells. Effective induction of apoptosis by combined treatment with CE and TRAIL was not blocked by Bcl-xL overexpression, which is known to confer resistance to various chemotherapeutic agents. While TRAIL-mediated proteolytic processing of procaspase-3 was partially blocked in various CRC cells treated with TRAIL alone, co-treatment with CE efficiently recovered TRAIL-induced caspase activation. We observed that CE treatment of CRC cells did not change the expression of anti-apoptotic proteins and pro-apoptotic proteins, including death receptors (DR4 and DR5). However, CE treatment markedly reduced the protein level of the short form of the cellular FLICE-inhibitory protein (c-FLIPS), an inhibitor of caspase-8, via proteasome-mediated degradation. Collectively, these observations show that CE recovers TRAIL sensitivity in various CRC cells via down-regulation of c-FLIPS.