Chaetocin induces cell cycle arrest and apoptosis by regulating the ROS-mediated ASK-1/JNK signaling pathways

The potential of cancer stem cells for personalized risk assessment and therapeutic intervention in individuals with intrahepatic cholangiocarcinoma

BACKGROUND

Accumulating evidence suggests that intrahepatic cholangiocarcinoma (ICC) is a stem cell-based disease, but information on the biology of cancer stem cells (CSC) in ICC is very limited.

METHODS

ICC RNA-seq cohorts from three different public databases were integrated and the protein-coding genes were divided into different modules using "WGCNA" to screen the most relevant modules with CSC scores. Least Absolute Shrinkage and Selection Operator (LASSO) regression were introduced to construct prognostic classification models. In addition, the extent of immune cell infiltration in patients in different risk groups was assessed based on the ESTIMATE, CIBERSORT, MCP-Counter, and single sample gene set enrichment analysis (ssGSEA) algorithms. Finally, the correlation between different risk scores and common drugs was analyzed by pRRophetic package and Spearman method.

RESULTS

In the present study, we found that a high CSC score was associated with a poorer prognosis in patients with ICC. The yellow module obtained by WGCNA was significantly positively correlated with the CSCs score, in which 8 genes were served to build a prognostic classification model, and the obtained risk score was negatively correlated with CSCs score and prognosis. The low-risk score was more suitable for immunotherapy, and the high-risk score was more suitable for treatment with 11 antitumor drugs.

CONCLUSION

This study revealed the regulatory role of CSC-mediated EMT, angiogenesis, and immunomodulatory biological processes in ICC, and applied a prognostic classification model to highlight the great potential of CSC for personalized risk assessment, chemotherapy, and immunotherapy intervention in ICC individuals.

Chaetocin-mediated SUV39H1 inhibition targets stemness and oncogenic networks of diffuse midline gliomas and synergizes with ONC201

BACKGROUND

Diffuse intrinsic pontine gliomas (DIPG/DMG) are devastating pediatric brain tumors with extraordinarily limited treatment options and uniformly fatal prognosis. Histone H3K27M mutation is a common recurrent alteration in DIPG and disrupts epigenetic regulation. We hypothesize that genome-wide H3K27M-induced epigenetic dysregulation makes tumors vulnerable to epigenetic targeting.

METHODS

We performed a screen of compounds targeting epigenetic enzymes to identify potential inhibitors for the growth of patient-derived DIPG cells. We further carried out transcriptomic and genomic landscape profiling including RNA-seq and CUT&RUN-seq as well as shRNA-mediated knockdown to assess the effects of chaetocin and SUV39H1, a target of chaetocin, on DIPG growth.

RESULTS

High-throughput small-molecule screening identified an epigenetic compound chaetocin as a potent blocker of DIPG cell growth. Chaetocin treatment selectively decreased proliferation and increased apoptosis of DIPG cells and significantly extended survival in DIPG xenograft models, while restoring H3K27me3 levels. Moreover, the loss of H3K9 methyltransferase SUV39H1 inhibited DIPG cell growth. Transcriptomic and epigenomic profiling indicated that SUV39H1 loss or inhibition led to the downregulation of stemness and oncogenic networks including growth factor receptor signaling and stemness-related programs; however, D2 dopamine receptor (DRD2) signaling adaptively underwent compensatory upregulation conferring resistance. Consistently, a combination of chaetocin treatment with a DRD2 antagonist ONC201 synergistically increased the antitumor efficacy.

CONCLUSIONS

Our studies reveal a therapeutic vulnerability of DIPG cells through targeting the SUV39H1-H3K9me3 pathway and compensatory signaling loops for treating this devastating disease. Combining SUV39H1-targeting chaetocin with other agents such as ONC201 may offer a new strategy for effective DIPG treatment.

TRAIL predisposes non-small cell lung cancer to ferroptosis by regulating ASK-1/JNK1 pathway

OBJECTIVE

Our current study aimed to assess the relationship between TNF-related apoptosis-inducing ligand (TRAIL) and ferroptosis in non-small cell lung cancer (NSCLC) development.

METHODS

The expression of TRAIL was detected by western blot, RT-qRCR and immunohistochemistry. The viability of NSCLC cells was analyzed by CCK-8 kit. The migration and invasion of NSCLC cells were detected by wound healing assay and transwell assay, respectively. Labile iron pool (LIP) was detected based on the calcein-acetoxymethyl ester method. Ferrous iron (Fe2+) and iron levels were assessed by detection kits. The levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were measured using corresponding detection kits. Mice tumor xenograft models were used for the in vivo research.

RESULTS

The expression of TRAIL was reduced in H1299, NCL-H1395, and A549 cells compared with BEAS-2B cells. The up-regulation of TRAIL expression significantly reduced cell viability, invasion, and migration of H1299 and A549 cells. TRAIL reduced the expression of ferroptosis-related genes (FTH1, GPX4, and SLC7A11), increased the levels of LIP, iron, and Fe2+, and promoted lipid peroxidation, thereby predisposing NSCLC cells to ferroptosis. TRAIL up-regulated the expression of phosphate modification of ASK-1 and JNK. ASKI-1 inhibitor GS-4977 attenuated the effects of TRAIL on the viability, migration, invasion, and ferroptosis of H1299 cells. Furthermore, TRAIL further suppressed tumor growth and ferroptosis in mice tumor xenograft models.

CONCLUSION

We indicated that overexpression of TRAIL induced ferroptosis in NSCLC cells and exerted anti-tumor effects. Mechanistically, TRAIL promoted ferroptosis by the activation of the ASK-1/JNK1 pathway. Our results may provide new therapeutic strategies for NSCLC.

Curcumin analog WZ26 induces ROS and cell death via inhibition of STAT3 in cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive biliary epithelial tumor with limited therapeutic options and poor prognosis. Curcumin is a promising active natural compound with several anti-cancer properties, though its clinical uses remain hindered due to its poor bioavailability. We recently synthesized curcumin analogs with multifunctional pharmacological and bioactivities with enhanced bioavailability. Among these novel curcumin analogs, WZ26 is a representative molecule. However, the anti-tumor effect of WZ26 against CCA is unclear. In this study, we evaluated the anti-tumor effect of WZ26 in both CCA cells and CCA xenograft mouse model. The underlying molecular anti-cancer mechanism of WZ26 was also studied. Our results show that WZ26 significantly inhibited cell growth and induced mitochondrial apoptosis in CCA cell lines, leading to significant inhibition of tumor growth in xenograft tumor mouse model. Treatment of WZ26 increased reactive oxygen species (ROS) generation, subsequently decreased mitochondrial membrane potential and inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3), thereby inducing G2/M cell cycle arrest and cell apoptosis. Pretreatment of N-acetyl cysteine (NAC), an antioxidant agent, could fully reverse the WZ26-induced ROS-mediated changes in CCA cells. Our findings provide experimental evidence that curcumin analog WZ26 could be a potential candidate against CCA via enhancing ROS induction and inhibition of STAT3 activation.

Effect of blue light on the cell viability of A549 lung cancer cells and investigations into its possible mechanism

Blue light has attracted extensive attention as a new potential cancer therapy. Recent studies have indicated that blue light has a significant inhibition effect on A459 cells. However, the effect of light parameters on the treatment of A549 cells and the mechanism of how blue light made the effect was still unclear. This study aimed to investigate A549 cells responses to blue light with varying irradiance and dose-dense, and tried to find out the mechanism of the effects blue light made. The results suggested that the responses of A549 cells to blue light with different irradiance and dose-dense were different and the decrease of cell viability reached saturation when the irradiance reached 3 mW/cm2 and the dose-dense reached 3.6 J/cm2 . It was assumed that blue light suppressed PI3K/AKT pathway and promoted the expression of JNK and p53 to affect the proliferation of A549 cells.

Multiple Mechanistic Action of Brevinin-1FL Peptide against Oxidative Stress Effects in an Acute Inflammatory Model of Carrageenan-Induced Damage

Amphibian skin is acknowledged to contain an antioxidant system composed of various gene-encoded antioxidant peptides, which exert significant effects on host defense. Nevertheless, recognition of such peptides is in its infancy so far. Here, we reported the antioxidant properties and underlying mechanism of a new antioxidant peptide, brevinin-1FL, identified from Fejervarya limnocharis frog skin. The cDNA sequence encoding brevinin-1FL was successfully cloned from the total cDNA of F. limnocharis and showed to contain 222 bp. The deduced mature peptide sequence of brevinin-1FL was FWERCSRWLLN. Functional analysis revealed that brevinin-1FL could concentration-dependently scavenge ABTS⁺, DPPH, NO, and hydroxyl radicals and alleviate iron oxidation. Besides, brevinin-1FL was found to show neuroprotective activity by reducing contents of MDA and ROS plus mitochondrial membrane potential, increasing endogenous antioxidant enzyme activity, and suppressing H₂O₂-induced death, apoptosis, and cycle arrest in PC12 cells which were associated with its regulation of AKT/MAPK/NF-κB signal pathways. Moreover, brevinin-1FL relieved paw edema, decreased the levels of TNF-α, IL-1β, IL-6, MPO, and malondialdehyde (MDA), and restored catalase (CAT) and superoxide dismutase (SOD) activity plus glutathione (GSH) contents in the mouse injected by carrageenan. Together, these findings indicate that brevinin-1FL as an antioxidant has potent therapeutic potential for the diseases induced by oxidative damage. Meanwhile, this study will help us further comprehend the biological functions of amphibian skin and the mechanism by which antioxidants protect cells from oxidative stress.

Chaetocin: A review of its anticancer potentials and mechanisms

Chaetocin is a natural metabolite product with various biological activities and pharmacological functions isolated from Chaetomium species fungi belonging to the thiodiketopyrazines. Numerous studies have demonstrated a wide range of antitumor activities of chaetocin in vitro and in vivo. Several studies have demonstrated that chaetocin suppresses the growth and proliferation of various tumour cells by regulating multiple signalling pathways related to tumour initiation and progression, inducing cancer cell apoptosis (intrinsic and extrinsic), enhancing autophagy, inducing cell cycle arrest, and inhibiting tumour angiogenesis, invasion, and migration. The antitumor effects and molecular mechanisms of chaetocin are reviewed and analysed in this paper, and the prospective applications of chaetocin in cancer prevention and therapy are also discussed. This review aimed to summarize the recent advances in the antitumor activity of chaetocin and to provide a rationale for further exploring the potential application of chaetocin in overcoming cancer in the future.

Lysine Methyltransferase Inhibitors Impair H4K20me2 and 53BP1 Foci in Response to DNA Damage in Sarcomas, a Synthetic Lethality Strategy

Background

Chromatin is dynamically remodeled to adapt to all DNA-related processes, including DNA damage responses (DDR). This adaptation requires DNA and histone epigenetic modifications, which are mediated by several types of enzymes; among them are lysine methyltransferases (KMTs).

Methods

KMT inhibitors, chaetocin and tazemetostat (TZM), were used to study their role in the DDR induced by ionizing radiation or doxorubicin in two human sarcoma cells lines. The effect of these KMT inhibitors was tested by the analysis of chromatin epigenetic modifications, H4K16ac and H4K20me2. DDR was monitored by the formation of γH2AX, MDC1, NBS1 and 53BP1 foci, and the induction of apoptosis.

Results

Chaetocin and tazemetostat treatments caused a significant increase of H4K16 acetylation, associated with chromatin relaxation, and increased DNA damage, detected by the labeling of free DNA-ends. These inhibitors significantly reduced H4K20 dimethylation levels in response to DNA damage and impaired the recruitment of 53BP1, but not of MDC1 and NBS1, at DNA damaged sites. This modification of epigenetic marks prevents DNA repair by the NHEJ pathway and leads to cell death.

Conclusion

KMT inhibitors could function as sensitizers to DNA damage-based therapies and be used in novel synthetic lethality strategies for sarcoma treatment.

Nuciferine Attenuates Doxorubicin-Induced Cardiotoxicity: An In Vitro and In Vivo Study

Chemotherapeutic drugs are a known factor that impairs the system of life due to their severe side effects. A more worrying fact is that the patients administered with doxorubicin fall under the risk of cardiotoxicity. The evolution of exploring plant-derived compounds is a possible way to combat health issues in therapeutic applications. Hence, this study focuses on the protective effect of plant-based compound nuciferine (NFN) against doxorubicin-induced cardiotoxicity in both in vitro and in vivo models. In this investigation, nuciferine significantly reduces DOX-mediated cardiotoxicity by mitigating reactive oxygen species, thereby preventing DNA fragmentation, regulating apoptosis genes and reducing the caspase 3/7 levels in vitro. Besides, nuciferine has shown significant protection against DOX-induced cardiac impairment and the upregulation of cardiogenic markers in vivo. The DOX-induced oxidative stress can be mitigated via enhancing the endogenous antioxidants, thereby controlling ROS-mediated apoptosis. In virtue of these potential features, nuciferine can be a budding candidate to address therapeutic needs.

Effect of sericin on the p38MAPK signaling pathway and NLRP3 inflammasome in the kidney of type 2 diabetic rats

The present study aimed to investigate the effects of sericin on the p38MAPK signaling pathway and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in the kidney of rats with type 2 diabetes mellitus (T2DM). A total of 36 male Sprague-Dawley rats were randomly divided into the normal group, T2DM model group and sericin group (n=12 rats/group). A T2DM model was developed through intraperitoneal injection of streptozotocin (35 mg·kg^-1·d^-1 for 2 consecutive days), and a high-fat and high-sugar diet. The T2DM rats in the sericin group were administered 2.4 g·kg^-1·d^-1 sericin for 35 days, and rats in the other groups were administered an equal volume of normal saline for 35 days. Fasting blood glucose was measured using the glucose oxidase method. Kidney tissue morphology was observed by H&E staining. Immunohistochemistry, western blotting, ELISA and reverse transcription-quantitative PCR were used to detect the levels of MKK6, p38MAPK, phosphorylated (p)-p38MAPK, NF-κB, IL-1β, IL-6, NLRP3 and caspase-1 in rat kidney tissues. The results revealed that blood glucose concentration, and the expression levels of MKK6, p-p38MAPK, NF-κB, IL-1β, IL-6, NLRP3 and caspase-1 were significantly increased in the T2DM group compared with those in the normal group (P<0.05). In addition, obvious pathological changes were observed in the T2DM group. Conversely, glucose concentration, and the expression levels of MKK6, p-p38MAPK, NF-κB, IL-1β, IL-6, NLRP3 and caspase-1 were significantly reduced in the sericin group compared with those in the T2DM group (P<0.05). The pathological changes were also obviously reduced. Notably, there was no significant difference in p38MAPK expression among the three groups (P>0.05). Collectively, the present study revealed that sericin may downregulate the expression levels of MKK6, p-p38MAPK, NF-κB, IL-1β, IL-6, NLRP3 and caspase-1, and inhibit activation of renal p38MAPK signaling and NLRP3-associated inflammation, which in turn may protect against kidney damage caused by T2DM.

Glycosylation end products mediate damage and apoptosis of periodontal ligament stem cells induced by the JNK-mitochondrial pathway

Background: Recent studies have confirmed the bidirectional relationship between the two and the exacerbation of periodontitis by type II diabetes mellitus (T2DM), the pathogenic mechanism has not yet been clarified, AGEs has been linked to the pathogenesis of both periodontitis and T2DM, JNK signaling pathway might play a important role to explain the inner mechanism.

Objectives: To study advanced glycation end products (AGEs) activate the innate immune system of the host by activating oxidative stress and affecting cellular signal transduction in periodontal ligament stem cells (PDLSCs);

Results: TNF-α and/or AGEs can induce the formation of endogenous ROS in PDLSCs, thereby activating the downstream JNK signalling pathway, leading to the initiation of the mitochondria-mediated apoptotic pathway and the induction of PDLSC apoptosis.

Conclusion: we hypothesized that the JNK pathway is a key link in the apoptosis of PDLSCs mediated by TNF-α and/or AGEs.

Materials and Methods: PDLSCs from healthy volunteers were extracted, cultured and stimulated with TNF-a and/or AGEs, Flow cytometry, CCK-8, multidifferential assay, RT-PCR, apoptosis assay, Transmission electron microscopy and Western blotting were recruit to detect the internal relations between AGEs and PDLSCs.

The fungal metabolite chaetocin is a sensitizer for pro-apoptotic therapies in glioblastoma

Glioblastoma Multiforme (GBM) is the most common and aggressive primary brain tumor. Despite recent developments in surgery, chemo- and radio-therapy, a currently poor prognosis of GBM patients highlights an urgent need for novel treatment strategies. TRAIL (TNF Related Apoptosis Inducing Ligand) is a potent anti-cancer agent that can induce apoptosis selectively in cancer cells. GBM cells frequently develop resistance to TRAIL which renders clinical application of TRAIL therapeutics inefficient. In this study, we undertook a chemical screening approach using a library of epigenetic modifier drugs to identify compounds that could augment TRAIL response. We identified the fungal metabolite chaetocin, an inhibitor of histone methyl transferase SUV39H1, as a novel TRAIL sensitizer. Combining low subtoxic doses of chaetocin and TRAIL resulted in very potent and rapid apoptosis of GBM cells. Chaetocin also effectively sensitized GBM cells to further pro-apoptotic agents, such as FasL and BH3 mimetics. Chaetocin mediated apoptosis sensitization was achieved through ROS generation and consequent DNA damage induction that involved P53 activity. Chaetocin induced transcriptomic changes showed induction of antioxidant defense mechanisms and DNA damage response pathways. Heme Oxygenase 1 (HMOX1) was among the top upregulated genes, whose induction was ROS-dependent and HMOX1 depletion enhanced chaetocin mediated TRAIL sensitization. Finally, chaetocin and TRAIL combination treatment revealed efficacy in vivo. Taken together, our results provide a novel role for chaetocin as an apoptosis priming agent and its combination with pro-apoptotic therapies might offer new therapeutic approaches for GBMs.

Double the Chemistry, Double the Fun: Structural Diversity and Biological Activity of Marine-Derived Diketopiperazine Dimers

While several marine natural products bearing the 2,5-diketopiperazine ring have been reported to date, the unique chemistry of dimeric frameworks appears to remain neglected. Frequently reported from marine-derived strains of fungi, many naturally occurring diketopiperazine dimers have been shown to display a wide spectrum of pharmacological properties, particularly within the field of cancer and antimicrobial therapy. While their structures illustrate the unmatched power of marine biosynthetic machinery, often exhibiting unsymmetrical connections with rare linkage frameworks, enhanced binding ability to a variety of pharmacologically relevant receptors has been also witnessed. The existence of a bifunctional linker to anchor two substrates, resulting in a higher concentration of pharmacophores in proximity to recognition sites of several receptors involved in human diseases, portrays this group of metabolites as privileged lead structures for advanced pre-clinical and clinical studies. Despite the structural novelty of various marine diketopiperazine dimers and their relevant bioactive properties in several models of disease, to our knowledge, this attractive subclass of compounds is reviewed here for the first time.

Chaetocin induces caspase-dependent apoptosis in ovarian cancer cells via the generation of reactive oxygen species

Ovarian cancer (OC) is one of the most common types of cancer among women worldwide. The majority of patients with OC respond to current chemotherapy approaches initially; however, patients are likely to experience cancer recurrence and become resistant to the chemotherapy. Therefore, novel agents for the treatment of OC are urgently required. Chaetocin, a natural product isolated from Chaetomium fungi, has been reported to exhibit anticancer activity against various types of cancer; however, the pharmacological action and detailed mechanism underlying the effects of chaetocin on OC cells remain unclear. Therefore, the present study investigated the cytotoxic effects of chaetocin on OC cells. A Cell Counting kit-8 assay was used to study cell viability, a colony formation assay was used to assess cell proliferation, flow cytometry was used to detect apoptosis, cell cycle and reactive oxygen species (ROS) generation, and western blotting was used to determine the protein levels of poly (ADP-ribose) polymerase, caspase-3 and cleaved-caspase-3. The results demonstrated that chaetocin significantly decreased the viability of OC cells. Chaetocin inhibited the proliferation and induced G₂/M phase arrest of the OVCAR-3 OC cell line. Additionally, chaetocin induced apoptotic cell death in OVCAR-3 cells via the caspase pathway. It was observed that chaetocin induced the accumulation of ROS in OVCAR-3 cells. Treatment with the ROS scavenger N-acetyl-L-cysteine reversed the apoptotic effects and activation of the caspase pathway induced by chaetocin. Collectively, these results revealed that chaetocin suppressed the proliferation and promoted the caspase-dependent apoptosis of OC cells by increasing the levels of ROS. Therefore, chaetocin may serve as a potential therapeutic agent for the treatment of OC.

Qingjie Fuzheng granules inhibit colorectal cancer cell growth by the PI3K/AKT and ERK pathways

BACKGROUND

Qingjie Fuzheng granules (QFGs) are part of a traditional Chinese medicine formula, which has been widely used and found to be clinically effective with few side effects in various cancer treatments, including colorectal cancer (CRC). However, the precise mechanisms and molecular signaling pathways involved in the activity of QFGs' anticancer effect have not been reported in the literature. In this study, we hypothesized that QFGs can inhibit the growth of colorectal cancer cells, and that its mechanism is closely related to one or more intracellular signal transduction pathways.

AIM

To better evaluate the mechanism underlying the anti-cancer effect of QFGs on the CRC cell lines HCT-116 and HCT-8.

METHOD

First, we measured cell viability and cytotoxicity by performing MTT and lactate dehydrogenase (LDH) assays. We evaluated the role of QFGs in cell proliferation and apoptosis by assessing colony formation and analyzing Hoechst 33258 staining. Second, cell cycle and apoptosis rates were measured by fluorescence activated cell sorting, and the expression levels of survivin, cyclin D1, CDK4, p21, Bax, Bcl-2, Fas, FasL, and cleaved-caspase-3/-8/-9 were measured by performing western blots and caspase activity assays. Furthermore, inhibitors of caspase-3/-8/-9 were used to elucidate the specific apoptosis pathway induced by QFGs in cancer cells. Finally, activation of the PI3K/AKT and ERK signaling pathways was examined using the western blot assay to investigate the possible mechanism.

RESULTS

MTT and LDH assays revealed that after 0.5-2.0 mg/mL of QFGs treatment, cell viability was reduced by (6.90% ± 1.03%)-(59.70% ± 1.51%) (HCT-116; P < 0.05) and (5.56% ± 4.52%)-(49.44% ± 2.47%) (HCT-8; P < 0.05), and cytotoxicity was increased from 0.52 ± 0.023 to 0.77 ± 0.002 (HCT-116; P < 0.01) and from 0.56 ± 0.054 to 0.81 ± 0.044 (HCT-8; P < 0.01) compared with the non-QFGs treatment groups. Additionally, colony formation and Hoechst 33258 staining assays showed that QFGs inhibited proliferation and induced apoptosis in CRC cells. QFGs also increased the expression levels of Bax, Fas and FasL, decreased the level of Bcl-2, and stimulated the activation of caspase-3/-8/-9, which were revealed by western blot and caspase activity assays. In contrast, when adding the three caspase inhibitors, the suppression effect of QFGs on cell viability and apoptosis were markedly inhibited. Moreover, QFGs suppressed the phosphorylation levels of PI3K, AKT and ERK.

CONCLUSION

These results demonstrated that QFGs can inhibit CRC cell proliferation and induce apoptosis by suppressing the PI3K/AKT and ERK signaling pathways.