Corilagin Induces High Levels of Apoptosis in the Temozolomide-Resistant T98G Glioma Cell Line

Corilagin exhibits differential anticancer effects through the modulation of STAT3/5 and MAPKs in human gastric cancer cells

Corilagin (CLG) is a hydrolyzable tannin and possesses various pharmacological activities. Here, we investigated the impact of CLG as an anti-tumor agent against human gastric tumor cells. We observed that CLG could cause negative regulation of JAKs-Src-STAT3/5 signaling axis in SNU-1 cells, but did not affect these pathways in SNU-16 cells. Interestingly, CLG promoted the induction of mitogen-activated protein kinases (MAPKs) signaling pathways in only SNU-16 cells, but not in the SNU-1 cells. CLG exhibited apoptotic effects that caused an increased accumulation of the cells in sub-G1 phase and caspase-3 activation in both SNU-1 and SNU-16 cell lines. We also noticed that CLG and docetaxel co-treatment could exhibit significantly enhanced apoptotic effects against SNU-1 cells. Moreover, the combinations treatment of CLG and docetaxel markedly inhibited cell growth, phosphorylation of JAK-Src-STAT3 and induced substantial apoptosis. Additionally, pharmacological inhibition of JNK, p38, and ERK substantially blocked CLG-induced activation of MAPKs, cell viability, and apoptosis, thereby implicating the pivotal role of MAPKs in the observed anti-cancer effects of CLG. Taken together, our data suggest that CLG could effectively block constitutive STAT3/5 activation in SNU-1 cells but induce sustained MAPKs activation in SNU-16 cells.

Up-Regulation of Cyclooxygenase-2 (COX-2) Expression by Temozolomide (TMZ) in Human Glioblastoma (GBM) Cell Lines

TMZ-resistance remains a main limitation in glioblastoma (GBM) treatment. TMZ is an alkylating agent whose cytotoxicity is modulated by O6-methylguanine-DNA methyltransferase (MGMT), whose expression is determined by MGMT gene promoter methylation status. The inflammatory marker COX-2 has been implicated in GBM tumorigenesis, progression, and stemness. COX-2 inhibitors are considered a GBM add-on treatment due to their ability to increase TMZ-sensitivity. We investigated the effect of TMZ on COX-2 expression in GBM cell lines showing different COX-2 levels and TMZ sensitivity (T98G and U251MG). β-catenin, MGMT, and SOX-2 expression was analyzed. The effects of NS398, COX-2 inhibitor, alone or TMZ-combined, were studied evaluating cell proliferation by the IncuCyte^® system, cell cycle/apoptosis, and clonogenic potential. COX-2, β-catenin, MGMT, and SOX-2 expression was evaluated by RT-PCR, Western blotting, and immunofluorescence and PGE2 by ELISA. Our findings, sustaining the role of COX-2/PGE2 system in TMZ-resistance of GBM, show, for the first time, a relevant, dose-dependent up-regulation of COX-2 expression and activity in TMZ-treated T98G that, in turn, correlated with chemoresistance. Similarly, all the COX-2-dependent signaling pathways involved in TMZ-resistance also resulted in being up-modulated after treatment with TMZ. NS398+TMZ was able to reduce cell proliferation and induce cell cycle arrest and apoptosis. Moreover, NS398+TMZ counteracted the resistance in T98G preventing the TMZ-induced COX-2, β-catenin, MGMT, and SOX-2 up-regulation.

Corilagin induces apoptosis and inhibits autophagy of HL‑60 cells by regulating miR‑451/HMGB1 axis

Corilagin is the primary active component of the Euphorbia phyllanthus plant and has significant anti-cancer properties. However, the biological effects and mechanisms of corilagin on acute myeloid leukemia (AML) have not been clarified. The Cell Counting Kit-8 and Carboxyfluorescein Diacetate Succinimidyl Ester assay results showed that corilagin significantly inhibited proliferation of the AML cell line HL-60 in a time- and dose-dependent manner. Western blotting and flow cytometry analysis were performed to determine the levels of apoptosis in HL-60 cells. The protein levels of cleaved caspase-3 and Bak were upregulated, while Bcl-xl was downregulated in cells treated with corilagin. The percentage of early- and late-stage apoptotic cells increased following corilagin treatment in a dose-dependent manner, indicating that the intrinsic mitochondrial apoptosis pathway was activated by corilagin. Simultaneously, western blotting and immunofluorescence results revealed that autophagy was suppressed; this was accompanied by a decrease in light chain 3-II (LC3-II) conversion and autophagosomes. MicroRNA (miRNA/miR) profile analysis showed that corilagin elevated the expression of the tumor suppressor miR-451, while the mRNA and protein levels of high mobility group protein B1 (HMGB1), the target of miR-451, decreased following exposure to corilagin. Knockdown of miR-451 decreased the downregulation of HMGB1 caused by corilagin, indicating negative regulation of HMGB1 by miR-451 during corilagin treatment. Furthermore, knockdown of miR-451 also attenuated corilagin-induced proliferation inhibition of HL-60 cells, implying that miR-451 was essential for the proliferation inhibitory effect of corilagin. In conclusion, these results indicated that corilagin induced apoptosis and inhibited autophagy in HL-60 cells by regulating the miR-451/HMGB1 axis, and corilagin may be a novel therapeutic drug for the treatment of AML.

Corilagin induces apoptosis and autophagy in NRF2‑addicted U251 glioma cell line

Corilagin, extracted from the Euphorbiaceae and Phyllanthus plants, inhibits the growth of a number of types of tumors. Compared with temozolomide, the traditional chemotherapy drug, corilagin has demonstrated stronger antitumor activity. However, the pharmaceutical mechanism of corilagin in glioma remains unclear. Nuclear factor erythroid 2 like 2 (NFE2L2 or NRF2) is positively associated with several types of tumor including glioma. In the present study, NRF2 expression was higher in glioma tissues compared with non-glioma specimens. Therefore, it was hypothesized that corilagin targets NRF2 regulation of U251 cell apoptosis. The present study used Hoechst 33258 staining to demonstrate that corilagin induced glioma cell apoptosis and observed that the expression of the apoptosis-related gene Bcl-2 was reduced. In addition, corilagin induced autophagy and promoted the conversion of light chain 3 (LC3) protein from LC3I to LC3II. NRF2 expression was downregulated by corilagin stimulation. Furthermore, the gene expression pattern following knockdown of NRF2 in U251 cells using siRNA was consistent with corilagin stimulation. Therefore, it was preliminarily concluded that corilagin induces apoptosis and autophagy by reducing NRF2 expression.

Corilagin induces human glioblastoma U251 cell apoptosis by impeding activity of (immuno)proteasome

Glioma is a type of common primary intracranial tumor, which is difficult to treat. It has been confirmed by research that corilagin (the primary active constituent of the matsumura leafflower herb) has significant antitumor effect. In particular, our previous research demonstrated that corilagin effectively promotes apoptosis of glioma U251 cells and has a synergistic effect when used with temozolomide. However, the mechanism by which corilagin causes apoptosis in U251 cells has yet to be investigated. Proteasomes are catalytic centers of the ubiquitin-proteasome system, which is the major protein degradation pathway in eukaryotic cells; they are primarily responsible for the degradation of signal molecules, tumor suppressors, cyclins and apoptosis inhibitors and serve an important role in tumor cell proliferation and apoptosis. The present study investigated the pro-apoptotic effect of corilagin on glioma U251 cells and confirmed that decreased proteasome activity and expression levels serve an important role in corilagin-induced U251 cell apoptosis.

A Peptide-Nucleic Acid Targeting miR-335-5p Enhances Expression of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene with the Possible Involvement of the CFTR Scaffolding Protein NHERF1

(1) Background: Up-regulation of the Cystic Fibrosis Transmembrane Conductance Regulator gene (CFTR) might be of great relevance for the development of therapeutic protocols for cystic fibrosis (CF). MicroRNAs are deeply involved in the regulation of CFTR and scaffolding proteins (such as NHERF1, NHERF2 and Ezrin). (2) Methods: Content of miRNAs and mRNAs was analyzed by RT-qPCR, while the CFTR and NHERF1 production was analyzed by Western blotting. (3) Results: The results here described show that the CFTR scaffolding protein NHERF1 can be up-regulated in bronchial epithelial Calu-3 cells by a peptide-nucleic acid (PNA) targeting miR-335-5p, predicted to bind to the 3′-UTR sequence of the NHERF1 mRNA. Treatment of Calu-3 cells with this PNA (R8-PNA-a335) causes also up-regulation of CFTR. (4) Conclusions: We propose miR-335-5p targeting as a strategy to increase CFTR. While the efficiency of PNA-based targeting of miR-335-5p should be verified as a therapeutic strategy in CF caused by stop-codon mutation of the CFTR gene, this approach might give appreciable results in CF cells carrying other mutations impairing the processing or stability of CFTR protein, supporting its application in personalized therapy for precision medicine.

Efficient Delivery of MicroRNA and AntimiRNA Molecules Using an Argininocalix[4]arene Macrocycle

MicroRNAs (miRNAs) are short non-coding RNA molecules acting as gene regulators by repressing translation or by inducing degradation of the target RNA transcripts. Altered expression of miRNAs may be involved in the pathogenesis of many severe human diseases, opening new avenues in the field of therapeutic strategies, i.e., miRNA targeting or miRNA mimicking. In this context, the efficient and non-toxic delivery of premiRNA and antimiRNA molecules might be of great interest. The aim of the present paper is to determine whether an argininocalix[4]arene is able to efficiently deliver miRNA, premiRNA, and antimiRNA molecules to target cells, preserving their biological activity. This study points out that (1) the toxicity of argininocalix[4]arene 1 is low, and it can be proposed for long-term treatment of target cells, being that this feature is a pre-requisite for the development of therapeutic protocols; (2) the delivery of premiRNA and antimiRNA molecules is efficient, being higher when compared with reference gold standards available; and (3) the biological activity of the premiRNAs and antimiRNAs is maintained. This was demonstrated using the argininocalix[4]arene 1 in miRNA therapeutic approaches performed on three well-described experimental model systems: (1) the induction of apoptosis by antimiR-221 in glioma U251 cells; (2) the induction of apoptosis by premiR-124 in U251 cells; and (3) the inhibition of pro-inflammatory IL-8 and IL-6 genes in cystic fibrosis IB3-1 cells. Our results demonstrate that the argininocalix[4]arene 1 should be considered a very useful delivery system for efficient transfer to target cells of both premiRNA and antimiRNA molecules, preserving their biological activity.

Corilagin in Cancer: A Critical Evaluation of Anticancer Activities and Molecular Mechanisms

Corilagin (β-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), an ellagitannin, is one of the major bioactive compounds present in various plants. Ellagitannins belong to the hydrolyzable tannins, a group of polyphenols. Corilagin shows broad-spectrum biological, and therapeutic activities, such as antioxidant, anti-inflammatory, hepatoprotective, and antitumor actions. Natural compounds possessing antitumor activities have attracted significant attention for treatment of cancer. Corilagin has shown inhibitory activity against the growth of numerous cancer cells by prompting cell cycle arrest at the G2/M phase and augmented apoptosis. Corilagin-induced apoptosis and autophagic cell death depends on production of intracellular reactive oxygen species in breast cancer cell line. It blocks the activation of both the canonical Smad and non-canonical extracellular-signal-regulated kinase/Akt (protein kinase B) pathways. The potential apoptotic action of corilagin is mediated by altered expression of procaspase-3, procaspase-8, procaspase-9, poly (ADP ribose) polymerase, and Bcl-2 Bax. In nude mice, corilagin suppressed cholangiocarcinoma growth and downregulated the expression of Notch1 and mammalian target of rapamycin. The aim of this review is to summarize the anticancer efficacy of corilagin with an emphasis on the molecular mechanisms involving various signaling pathways in tumor cells.

A new amido-phosphine of dichloroacetic acid as an active ligand for metals of pharmaceutical interest. Synthesis, characterization and tests of antiproliferative and pro-apoptotic activity

We herein describe the synthesis and characterization of the new amido-phosphinic ligand 3,7‑bis(dichloroacetyl)‑1,3,7‑triaza‑5‑phosphabicyclo[3.3.1]nonane (DCP), a derivative of dichloroacetic acid (DCA), whose ability to reverse the suppressed mitochondrial apoptosis in cancer cells is known. DCP was obtained by a double N-acylation of PTA (1,3,5‑triaza‑7‑phosphaadamantane) occurring with loss of CH₂, in appropriate conditions_. Due to the hindered rotation around the amidic CN bonds, three rotameric forms of DCP were observed, whose ratio in solution was dependent on the solvent, while the X-ray crystal structure of DCP showed an opposite orientation of the two amidic carbonyl groups (anti rotamer). The lipophilic, air and thermally stable DCP was found able to act regiospecifically as a P-donor ligand toward soft metal ions. By ligand substitution on appropriate precursors, we obtained the complexes 1-9, where proapoptotic DCA is associated with metal ions of known cytotoxic activity on cancer cells (Pt²⁺, Pd²⁺, Ru²⁺, Re⁺, Au⁺). The antiproliferative activity of DCP and its complexes was tested in vitro, in comparison with cisplatin, on three human tumor cell lines: A2780 (ovarian cisplatin-sensitive), A2780cis (ovarian cisplatin-resistant) and K562 (erythroleukemic). The results showed that the simultaneous presence of DCP (containing two residues of proapoptotic DCA) and Pt(II) produces the best performances with respect to non-platinum complexes. Experiments of pro-apoptotic activity indicated that the antiproliferative activity of the most active DCP-Pt(II) complexes is associated with induction of apoptosis.

Corilagin induces apoptosis, autophagy and ROS generation in gastric cancer cells in vitro

Corilagin, a unique component of the tannin family, has been identified in several medicinal plants. In previous literature, corilagin exhibited a marked anticancer property in a variety of human cancer cells. However, the biological effects of corilagin on gastric cancer and the mechanisms involved remain to be fully elucidated. In the present study, it was reported that corilagin induced inhibition of cell growth in SGC7901 and BGC823 cells in a concentration-dependent manner. It was found that corilagin exhibited less toxicity towards normal GES-1 cells. Furthermore, the study showed that corilagin induced the apoptosis of gastric cancer cells mainly via activating caspase-8, -9, -3 and poly ADP-ribose polymerase proteins. Simultaneously, it was verified that corilagin triggered autophagy in gastric cancer cells and the inhibition of autophagy improved the activity of corilagin on cell growth suppression. In addition, corilagin significantly increased intracellular reactive oxygen species production, which is important in inhibiting the growth of gastric cancer cells. Finally, it was shown that necroptosis cannot be induced by corilagin-incubation in SGC7901 and BGC823 cell lines. Consequently, these findings indicate that corilagin may be developed as a potential therapeutic drug for gastric cancer.

Synthesis of new allyl palladium complexes bearing purine-based NHC ligands with antiproliferative and proapoptotic activities on human ovarian cancer cell lines

A series of new palladium allyl complexes bearing purine-based carbenes derived from caffeine, theophylline and theobromine have been prepared and characterized by NMR spectroscopy, and elemental analysis and in two cases by single crystal X-ray diffraction. The cytotoxic and proapoptotic activities of compounds have been determined in vitro on human ovarian cancer A2780 and SKOV-3 cell lines. These experiments have shown that the palladium-allyl fragment induces a general cytotoxicity, but the choice of the supporting ligands is of paramount importance for achieving the best results. In particular complexes 4c, 4d and 5d exhibit a higher antiproliferative effect (IC50: 0.09, 0.81 and 0.85 μM respectively) than cisplatin (IC50: 1.5 μM) on A2780 cells, and 4d (IC50: 1.7 μM vs. 5.94 μM) on SKOV-3 cell line. Moreover in many cases it has been proved that the cytotoxicity of our complexes is associated with the induction of apoptosis.

Corilagin inhibits breast cancer growth via reactive oxygen species-dependent apoptosis and autophagy

Corilagin is a component of Phyllanthus urinaria extract and has been found of possessing anti‐inflammatory, anti‐oxidative, and anti‐tumour properties in clinic treatments. However, the underlying mechanisms in anti‐cancer particularly of its induction of cell death in human breast cancer remain undefined. Our research found that corilagin‐induced apoptotic and autophagic cell death depending on reactive oxygen species (ROS) in human breast cancer cell, and it occurred in human breast cancer cell (MCF‐7) only comparing with normal cells. The expression of procaspase‐8, procaspase‐3, PARP, Bcl‐2 and procaspase‐9 was down‐regulated while caspase‐8, cleaved PARP, caspase‐9 and Bax were up‐regulated after corilagin treatment, indicating apoptosis mediated by extrinsic and mitochondrial pathways occurred in MCF‐7 cell. Meanwhile, autophagy mediated by suppressing Akt/mTOR/p70S6K pathway was detected with an increase in autophagic vacuoles and LC3‐II conversion. More significantly, inhibition of autophagy by chloroquine diphosphate salt (CQ) remarkably enhanced apoptosis, while the caspase inhibitor z‐VAD‐fmk failed in affecting autophagy, suggesting that corilagin‐induced autophagy functioned as a survival mechanism in MCF‐7 cells. In addition, corilagin induced intracellular reactive oxygen species (ROS) generation, when reduced by ROS scavenger NAC, apoptosis and autophagy were both down‐regulated. Nevertheless, in SK‐BR3 cell which expressed RIP3, necroptosis inhibitor Nec‐1 could not alleviate cell death induced by corilagin, indicating necroptosis was not triggered. Subcutaneous tumour growth in nude mice was attenuated by corilagin, consisting with the results in vitro. These results imply that corilagin inhibits cancer cell proliferation through inducing apoptosis and autophagy which regulated by ROS release.

Corilagin, a promising medicinal herbal agent

Corilagin, a gallotannin, is one of the major active components of many ethnopharmacological plants. It was isolated from Caesalpinia coriaria (Jacq.) Willd. (dividivi) by Schmidt in 1951 for the first time. In the past few decades, corilagin was reported to exhibit anti-tumor, anti-inflammatory and hepatoprotective activities, etc. However, little attention was paid to its pharmacological properties due to the complicated and inefficient extract method. In recent years, with the development of extraction technology corilagin was much easier to obtain than before. Thus, people return to pay attention to its anti-tumor, hepatoprotective, and anti-inflammatory activities, particularly as an anti-tumor agent candidate. Our research team had focused on the distribution, preparation and anti-tumor activity of corilagin since 2005. We found corilagin showed good anti-tumor activity on hepatocellular carcinoma and ovarian cancer. What's more, corilagin showed a low level of toxicity toward normal cells and tissues. Due to the extensive attention that corilagin has received, we present a systematic review of the pharmacological effects of corilagin. In this review, we summarized all the pharmacological effects of corilagin with a focus on the molecular mechanism of anti-tumor activity and show you how corilagin affected the signaling pathways of tumor cells as well as its physicochemical properties, distribution and preparation methods.