Raddeanin A promotes apoptosis and ameliorates 5-fluorouracil resistance in cholangiocarcinoma cells

An Inflammatory Checkpoint Generated by IL1RN Splicing Offers Therapeutic Opportunity for KRAS-Mutant Intrahepatic Cholangiocarcinoma

KRAS mutations are causally linked to protumor inflammation and are identified as driving factors in tumorigenesis. Here, using multiomics data gathered from a large set of patients, we showed that KRAS mutation was associated with a specific landscape of alternative mRNA splicing that connected to myeloid inflammation in intrahepatic cholangiocarcinoma (iCCA). Then, we identified a negative feedback mechanism in which the upregulation of interleukin 1 receptor antagonist (IL1RN)-201/203 due to alternative splicing confers vital anti-inflammatory effects in KRAS-mutant iCCA. In KRAS-mutant iCCA mice, both IL1RN-201/203 upregulation and anakinra treatment ignited a significant antitumor immune response by altering neutrophil recruitment and phenotypes. Furthermore, anakinra treatment synergistically enhanced anti-PD-1 therapy to activate intratumoral GZMB+ CD8+ T cells in KRAS-mutant iCCA mice. Clinically, we found that high IL1RN-201/203 levels in patients with KRAS-mutant iCCA were significantly associated with superior response to anti-PD-1 immunotherapy.

SIGNIFICANCE

This work describes a novel inflammatory checkpoint mediated by IL1RN alternative splicing variants that may serve as a promising basis to develop therapeutic options for KRAS-mutant iCCA and other cancers. This article is featured in Selected Articles from This Issue, p. 2109.

Establishment and characterization of a new intrahepatic cholangiocarcinoma cell line, ICC-X3

Intrahepatic cholangiocarcinoma (ICC) is an aggressive cancer of the biliary tract that is prone to recurrence and metastasis and is characterized by poor sensitivity to chemotherapy and overall prognosis. To address this challenge, the establishment of suitable preclinical models is critical. In this study, we successfully established a new ICC cell line, named ICC-X3, from the satellite lesions of one ICC patient. The cell line was characterized with respect to phenotypic, molecular, biomarker, functional and histological properties. STR confirmed that ICC-X3 was highly consistent with primary tumor tissue. ICC-X3 cells positively expressed CK7, CK19, E-cadherin, vimentin, and Ki67. ICC-X3 was all resistant to gemcitabine, paclitaxel, 5-FU, and oxaliplatin. The cell line was able to rapidly form xenograft tumors which were highly similar to the primary tumor. The missense mutation of TP53 exon was detected in ICC-X3 cells. ICC-X3 can be used as a good experimental model to study the progression, metastasis, and drug resistance of ICC.

Raddeanin A Improves the Therapeutic Effect of Osimertinib in NSCLC by Accelerating ROS/NLRP3-mediated Pyroptosis

BACKGROUND

Osimertinib (Osm) is the preferred treatment for non-small cell lung cancer (NSCLC) patients with the epidermal growth factor receptor (EGFR) T790M mutation. Nevertheless, the resistance of NSCLC cells to Osm will eventually develop, which remains the biggest obstacle to treating such diseases. Raddeanin A (RA) exhibits a potent anti-tumor effect on various types of cancer cells. In this study, we aimed to investigate whether RA suppresses NSCLC growth and increases the therapeutic effect of Osm.

METHODS

The effects of RA on inhibiting NSCLC cell viability and proliferation were tested using cell counting kit 8 (CCK-8) and EdU assay. The roles of RA in improving the anti-tumor effect of Osm were tested with CCK-8 and colony formation assays. The roles of RA in regulating reactive oxygen species (ROS)/NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3)-mediated pyroptosis were assessed using quantitative real- time PCR (qRT-PCR) and western blotting analysis.

RESULTS

RA treatment decreased A549 and H1975 cell viability in a dose- and time-dependent way. RA inhibited NSCLC cell proliferation and tumor growth in vivo. Mechanistically, RA induced ROS overgeneration and resulted in subsequent NLRP3-mediated pyroptosis. In particular, combination treatment with Osm and RA reduced cell viability and clonogenic growth capacity more efficiently than Osm mono treatment in A549 and H1975 cells. Combination treatment also promoted NLRP3-mediated pyroptosis more efficiently than Osm mono treatment.

CONCLUSION

RA inhibited the NSCLC growth and increased the anti-tumor role of Osm in NSCLC by facilitating ROS/NLRP3-mediated pyroptosis. These results suggested that combination therapy with RA and Osm might be an effective strategy to treat Osm-resistant NSCLC.

Proteogenomic characterization identifies clinically relevant subgroups of intrahepatic cholangiocarcinoma

We performed proteogenomic characterization of intrahepatic cholangiocarcinoma (iCCA) using paired tumor and adjacent liver tissues from 262 patients. Integrated proteogenomic analyses prioritized genetic aberrations and revealed hallmarks of iCCA pathogenesis. Aflatoxin signature was associated with tumor initiation, proliferation, and immune suppression. Mutation-associated signaling profiles revealed that TP53 and KRAS co-mutations may contribute to iCCA metastasis via the integrin-FAK-SRC pathway. FGFR2 fusions activated the Rho GTPase pathway and could be a potential source of neoantigens. Proteomic profiling identified four patient subgroups (S1-S4) with subgroup-specific biomarkers. These proteomic subgroups had distinct features in prognosis, genetic alterations, microenvironment dysregulation, tumor microbiota composition, and potential therapeutics. SLC16A3 and HKDC1 were further identified as potential prognostic biomarkers associated with metabolic reprogramming of iCCA cells. This study provides a valuable resource for researchers and clinicians to further identify molecular pathogenesis and therapeutic opportunities in iCCA.

Inhibition of microRNA-29b suppresses oxidative stress and reduces apoptosis in ischemic stroke

MicroRNAs (miRNAs) regulate protein expression by antagonizing the translation of mRNAs and are effective regulators of normal nervous system development, function, and disease. MicroRNA-29b (miR-29b) plays a broad and critical role in brain homeostasis. In this study, we tested the function of miR-29b in animal and cell models by inhibiting miR-29b expression. Mouse models of middle cerebral artery occlusion were established using the modified Zea-Longa suture method. Prior to modeling, 50 nmol/kg miR-29b antagomir was injected via the tail vein. MiR-29b expression was found to be abnormally increased in ischemic brain tissue. The inhibition of miR-29b expression decreased the neurological function score and reduced the cerebral infarction volume and cell apoptosis. In addition, the inhibition of miR-29b significantly decreased the malondialdehyde level, increased superoxide dismutase activity, and Bcl-2 expression, and inhibited Bax and Caspase3 expression. PC12 cells were treated with glutamate for 12 hours to establish in vitro cell models of ischemic stroke and then treated with the miR-29 antagomir for 48 hours. The results revealed that miR-29b inhibition in PC12 cells increased Bcl-2 expression and inhibited cell apoptosis and oxidative damage. These findings suggest that the inhibition of miR-29b inhibits oxidative stress and cell apoptosis in ischemic stroke, producing therapeutic effects in ischemic stroke. This study was approved by the Laboratory Animal Care and Use Committee of the First Affiliated Hospital of Zhengzhou University (approval No. 201709276S) on September 27, 2017.

Raddeanin A (RA) reduced acute inflammatory injury in mouse experimental cerebral hemorrhage by suppression of TLR4

Spontaneous intracerebral hemorrhage (ICH) is associated with high mortality and disability rates. The microglia-induced inflammatory response is a critical factor determining brain tissue damage after ICH. Raddeanin A (RA) is a natural triterpenoid compound with anti-inflammatory effects, although its effects on ICH and the underlying molecular mechanism have not been elucidated. In this study, we found that RA reduced the volume of cerebral hematoma and cerebral edema, attenuated neuronal apoptosis and improved the behavioral indices in a murine model of acute cerebral hemorrhage. Mechanistically, RA downregulated the TLR4-mediated pro-inflammatory effectors, reduced infiltration of microglia in peri-intracerebral hemorrhage and inhibited apoptosis of neurons co-cultured with activated microglia. In conclusion, RA can alleviate ICH-related tissue damage and promote the recovery of neuronal function by suppressing microglia-induced inflammation and apoptosis.

Raddeanin A induced apoptosis of non-small cell lung cancer cells by promoting ROS-mediated STAT3 inactivation

PURPOSE

Non-small cell lung cancer (NSCLC) is a high-risk type of lung cancer. Raddeanin A exerts anti-tumor activity by regulating cell proliferation and apoptosis, but its role in NSCLC remains to be elucidated. This study was to investigate the effect of raddeanin A in NSCLC and its mechanism.

METHODS

The effect of raddeanin A (2, 4, 8, 10 μmol/L) on the viability, proliferation and apoptosis of A549 and H1299 cells was determined by cell counting kit-8, colony formation and flow cytometry assays, respectively. Next, western blot was performed to examine the protein expressions of cleaved caspase-3, Bax, phosphorylated signal transducer and activator of transcription 3 (p-STAT3) and STAT3. Subsequently, the intracellular reactive oxygen species (ROS) generation and mitochondrial membrane potential of NSCLC cells were detected by 2', 7'-dichlorofluorescein-diacetate (DCFH-DA) and JC-1 assay. Lastly, the effect of N-acetylcysteine (NAC) on the apoptosis, ROS generation, and STAT3 was evaluated by the above-mentioned assays again.

RESULTS

Raddeanin A treatment had no obvious effect on 16HBE cells viability, but it inhibited viability and proliferation of A549 and H1299 cells, promoted the apoptosis, increased the protein expressions of cleaved caspase-3 and Bax, generated intracellular ROS, as well as decreased mitochondrial membrane potential and the expressions of p-STAT3 and STAT3 in A549 and H1299 cells. After cells treated with NAC, the effect of raddeanin A was reversed, as evidenced by the apoptosis and ROS generation were suppressed, and the expression of p-STAT3 was promoted.

CONCLUSION

Raddeanin A suppressed the proliferation and induced apoptosis of NSCLC cells via promoting the ROS-mediated STAT3 inactivation.

The study of Raddeanin A cerebrovascular endothelial cell trafficking through P-glycoprotein

As one of the natural triterpenoids isolated from Anemone Raddeana Regel, Raddeanin A (RA) has been confirmed to possess therapeutic effects against multiple tumorigeneses, especially for the onset of glioblastoma and growth in human brains. However, the mechanism by which this happens remains poorly understood in terms of the vascular endothelium trafficking routine of RA through the brain-blood barrier (BBB). To seek such answers, human brain microenvironment endothelial cells (HBMECs) were used to stimulate the microenvironment in vitro, and to explore the intracellular accumulation of RA. The results of this experiment illustrated that RA has a relative moderate transport affinity for such cells. The kinetic parameter K_m was 37.01 ± 2.116 μM and V_max was 9.412 ± 0.1375 nM/min/mg of protein. Interestingly, protein downregulation of P-glycoprotein (P-gp, ABCB1/MDR1) significantly activated RA transmembrane activity, which proves that P-gp is responsible for RA cellular trafficking. In addition, the selective non-specific inhibitor, LY335979 increased either RA or the classical substrate of P-gp, digoxin, intracellular accumulation by restricting the transporter's function but without jeopardizing cytomembrane proteins. Moreover, a decrease in the expression or activity of P-gp triggered RA drug resistance to HBMECs. In summary, our data showed that both the expression and function of P-gp are all necessary for RA transmembrane trafficking through cerebrovascular endothelial cells. This study provides significant evidence for the presence of a connection between RA transport and P-gp variation during drug BBB penetration. It is also suggesting some vital guidance on the RA pharmacodynamic effect in human brains.

Raddeanin A inhibited epithelial-mesenchymal transition (EMT) and angiogenesis in glioblastoma by downregulating β-catenin expression

Raddeanin A (RA), an oleanane-type triterpenoid saponin derived from Anemone raddeana Regel, has been found to suppress the viability and metastasis of several cancers, including GBM, through various signaling pathways. However, the mechanisms underlying the anti-GBM properties of RA have not been fully elucidated. Epithelial to mesenchymal transition (EMT) and angiogenesis are important for the genesis and progression of GBM. These two crucial processes can be regulated by multiple molecular, including β-catenin, which has been demonstrated to act as a pro-tumorigenic molecular. In this study, we aimed to determine whether RA could suppress EMT and angiogenesis by inhibiting the action of β-catenin in GBM. We found that RA inhibited the proliferation, invasion and migratory properties of GBM cells. RA was also found to have downregulated the expressions of β-catenin and EMT-related biomarkers (N-cadherin, vimentin, and snail). In addition, the overexpression of β-catenin reversed the therapeutic effects of RA exerted on the EMT of GBM cells. RA restricted angiogenesis, as shown by the tube formation assay and CAM assay, while it downregulated VEGF levels in HUVECs. Moreover, massive β-catenin could reverse the suppression of angiogenesis induced by RA. Finally, we demonstrated that RA inhibited tumor growth and prolonged survival time in an intracranial U87 xenograft mouse model. Similar to the results in vitro, RA downregulated the expression of β-catenin, EMT makers and VEGF, and decreased vessel density in vivo. In summary, our results demonstrated that RA repressed GBM via downregulating β-catenin-mediated EMT and angiogenesis both in vitro and in vivo.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

Anticancer Potential of Raddeanin A, a Natural Triterpenoid Isolated from Anemone raddeana Regel

Natural compounds extracted from plants have gained immense importance in the fight against cancer cells due to their lesser toxicity and potential therapeutic effects. Raddeanin A (RA), an oleanane type triterpenoid is a major compound isolated from Anemone raddeana Regel. As an anticancer agent, RA induces apoptosis, cell cycle arrest, inhibits invasion, migration and angiogenesis in malignant cell lines as well as in preclinical models. In this systemic review, the pharmacological effects of RA and its underlying molecular mechanisms were carefully analyzed and potential molecular targets have been highlighted. The apoptotic potential of RA can be mediated through the modulation of Bcl-2, Bax, caspase-3, caspase-8, caspase-9, cytochrome c and poly-ADP ribose polymerase (PARP) cleavage. PI3K/Akt signaling pathway serves as the major molecular target affected by RA. Furthermore, RA can block cell proliferation through inhibition of canonical Wnt/β-catenin signaling pathway in colorectal cancer cells. RA can also alter the activation of NF-κB and STAT3 signaling pathways to suppress invasion and metastasis. RA has also exhibited promising anticancer potential against drug resistant cancer cells and can enhance the anticancer effects of several chemotherapeutic agents. Overall, RA may function as a promising compound in combating cancer, although further in-depth study is required under clinical settings to validate its efficacy in cancer patients.

Comprehensive analysis of DNA methylation and gene expression profiles in cholangiocarcinoma

BACKGROUND

The incidence of cholangiocarcinoma (CCA) has risen in recent years, and it has become a significant health burden worldwide. However, the mechanisms underlying tumorigenesis and progression of this disease remain largely unknown. An increasing number of studies have demonstrated crucial biological functions of epigenetic modifications, especially DNA methylation, in CCA. The present study aimed to identify and analyze methylation-regulated differentially expressed genes (MeDEGs) involved in CCA tumorigenesis and progression by bioinformatics analysis.

METHODS

The gene expression profiling dataset (GSE119336) and gene methylation profiling dataset (GSE38860) were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) and differentially methylated genes (DMGs) were identified using the limma packages of R and GEO2R, respectively. The MeDEGs were obtained by overlapping the DEGs and DMGs. Functional enrichment analyses of these genes were then carried out. Protein-protein interaction (PPI) networks were constructed using STRING and visualized in Cytoscape to determine hub genes. Finally, the results were verified based on The Cancer Genome Atlas (TCGA) database.

RESULTS

We identified 98 hypermethylated, downregulated genes and 93 hypomethylated, upregulated genes after overlapping the DEGs and DMGs. These genes were mainly enriched in the biological processes of the cell cycle, nuclear division, xenobiotic metabolism, drug catabolism, and negative regulation of proteolysis. The top nine hub genes of the PPI network were F2, AHSG, RRM2, AURKB, CCNA2, TOP2A, BIRC5, PLK1, and ASPM. Moreover, the expression and methylation status of the hub genes were significantly altered in TCGA.

CONCLUSIONS

Our study identified novel methylation-regulated differentially expressed genes (MeDEGs) and explored their related pathways and functions in CCA, which may provide novel insights into a further understanding of methylation-mediated regulatory mechanisms in CCA.