Emetine Dihydrochloride: A Novel Therapy for Bladder Cancer

Up-regulation of TNF-alpha/NFkB/SIRT1 axis drives aggressiveness and cancer stem cells accumulation in chemoresistant oral squamous cell carcinoma

Tumor resistance remains an obstacle to successfully treating oral squamous cell carcinoma (OSCC). Cisplatin is widely used as a cytotoxic drug to treat solid tumors, including advanced OSCC, but with low efficacy due to chemoresistance. Therefore, identifying the pathways that contribute to chemoresistance may show new possibilities for improving the treatment. This work explored the role of the tumor necrosis factor-alpha (TNF-alpha)/NFkB signaling in driving the cisplatin resistance of OSCC and its potential as a pharmacological target to overcome chemoresistance. Differential accessibility analysis demonstrated the enrichment of opened chromatin regions in members of the TNF-alpha/NFkB signaling pathway, and RNA-Seq confirmed the upregulation of TNF-alpha/NFkB signaling in cisplatin-resistant cell lines. NFkB was accumulated in cisplatin-resistant cell lines and in cancer stem cells (CSC), and the administration of TNF-alpha increased the CSC, suggesting that TNF-alpha/NFkB signaling is involved in the accumulation of CSC. TNF-alpha stimulation also increased the histone deacetylases HDAC1 and SIRT1. Cisplatin-resistant cell lines were sensitive to the pharmacological inhibition of NFkB, and low doses of the NFkB inhibitors, CBL0137, and emetine, efficiently reduced the CSC and the levels of SIRT1, increasing histone acetylation. The NFkB inhibitors decreased stemness potential, clonogenicity, migration, and invasion of cisplatin-resistant cell lines. The administration of the emetine significantly reduced the tumor growth of cisplatin-resistant xenograft models, decreasing NFkB and SIRT1, increasing histone acetylation, and decreasing CSC. TNF-alpha/NFkB/SIRT1 signaling regulates the epigenetic machinery by modulating histone acetylation, CSC, and aggressiveness of cisplatin-resistant OSCC and the NFkB inhibition is a potential strategy to treat chemoresistant OSCC.

Emetine dihydrochloride alleviated radiation-induced lung injury through inhibiting EMT

Radiation-induced lung injury (RILI), divided into early radiation pneumonia (RP) and late radiation-induced pulmonary fibrosis (RIPF), is a common serious disease after clinical chest radiotherapy or nuclear accident, which seriously threatens the life safety of patients. There has been no effective prevention or treatment strategy till now. Epithelial-mesenchymal transition (EMT) is a key step in the occurrence and development of RILI. In this study, we demonstrated that emetine dihydrochloride (EDD) alleviated RILI through inhibiting EMT. We found that EDD significantly attenuated EMT-related markers, reduced Smad3 phosphorylation expression after radiation. Then, for the first time, we observed EDD alleviated lung hyperaemia and reduced collagen deposit induced by irradiation, providing protection against RILI. Finally, it was found that EDD inhibited radiation-induced EMT in lung tissues. Our study suggested that EDD alleviated RILI through inhibiting EMT by blocking Smad3 signalling pathways. In summary, our results indicated that EDD is a novel potential radioprotector for RILI.

Genome-wide siRNA screens identify RBBP9 function as a potential target in Fanconi anaemia-deficient head-and-neck squamous cell carcinoma

Fanconi anaemia (FA) is a rare chromosomal-instability syndrome caused by mutations of any of the 22 known FA DNA-repair genes. FA individuals have an increased risk of head-and-neck squamous-cell-carcinomas (HNSCC), often fatal. Systemic intolerance to standard cisplatin-based protocols due to somatic-cell hypersensitivity underscores the urgent need to develop novel therapies. Here, we performed unbiased siRNA screens to unveil genetic interactions synthetic-lethal with FA-pathway deficiency in FA-patient HNSCC cell lines. We identified based on differential-lethality scores between FA-deficient and FA-proficient cells, next to common-essential genes such as PSMC1, PSMB2, and LAMTOR2, the otherwise non-essential RBBP9 gene. Accordingly, low dose of the FDA-approved RBBP9-targeting drug Emetine kills FA-HNSCC. Importantly both RBBP9-silencing as well as Emetine spared non-tumour FA cells. This study provides a minable genome-wide analyses of vulnerabilities to address treatment challenges in FA-HNSCC. Our investigation divulges a DNA-cross-link-repair independent lead, RBBP9, for targeted treatment of FA-HNSCCs without systemic toxicity.

Different Aspects of Emetine's Capabilities as a Highly Potent SARS-CoV-2 Inhibitor against COVID-19

In the global movement to find the appropriate agents to fight the coronavirus disease of 2019 (COVID-19), emetine is one of the strongest anti-SARS-CoV-2 compounds with sub-micromolar EC50 values, identified in several studies and high-throughput screening efforts. The reported anti-SARS-CoV-2 mechanisms indicate the effect of this compound on both virus-based and host-based targets. In addition to having excellent antiviral effects, emetine can relieve COVID-19 patients by reducing inflammation through inhibitory activity against NF-κB by the mechanism of IκBα phosphorylation inhibition; it can also limit the lipopolysaccharide-induced expression of pro-inflammatory cytokines TNFα, IL-1β, and IL-6. Emetine also can well reduce pulmonary arterial hypertension as an important COVID-19 complication by modulating a variety of cellular processes such as the Rho-kinase/CyPA/Bsg signaling pathway. The therapeutic value of emetine for combating COVID-19 was highlighted when in vivo pharmacokinetic studies showed that the concentration of this compound in the lungs increases significantly higher than the EC50 of the drug. Despite its valuable therapeutic effects, emetine has some cardiotoxic effects that limit its use in high doses. However, high therapeutic capabilities make emetine a valuable lead compound that can be used for the design and development of less toxic anti-COVID-19 agents in the future. This Review provides a collection of information on the capabilities of emetine and its potential for the treatment of COVID-19, along with structural analysis which could be used for further research in the future.

Emetine exerts anticancer effects in U2OS human osteosarcoma cells via activation of p38 and inhibition of ERK, JNK, and β-catenin signaling pathways

Osteosarcoma (OS) is a primary bone neoplasm that is highly malignant. As advances in chemotherapy for the treatment of OS have stagnated, discovery of new reagents is required. Emetine is a phytochemical which can be isolated from a medicinal herb Cephaelis ipecacuanha and is traditionally used for amoebicides. Previous studies have demonstrated that emetine can possibly be repositioned for use in anticancer reagents. However, any anticancer effects and underlying mechanisms of emetine on human OS are not yet well understood. In this study, we analyzed the anticancer effects and involved cellular mechanisms after treatment with emetine to U2OS human OS cells. Emetine significantly reduced both the viability and proliferation, and induced apoptosis via activation of caspase-3 and caspase-7 in U2OS cells. Emetine effectively inhibited the migration and invasion of U2OS cells. Gelatinase activities of matrix metalloproteinase 2 (MMP-2) and MMP-9 were reduced by emetine. MMP-9 was transcriptionally inhibited, while MMP-2 was posttranscriptionally repressed, via the reduced expression of membrane-type I-matrix metalloproteinase (MT1-MMP). p38, which is closely related with induction of apoptosis, was stimulated by emetine. Extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and β-catenin, which are linked with expression of MMPs, were downregulated. Emetine exerted anticancer effects on MG63 human OS cells as well. Taken together, our study demonstrated the anticancer and antimetastatic potential of emetine in treating human OS for the first time. It is expected that emetine may be a promising drug candidate to be repositioned for chemotherapy of OS.

Pathways, Processes, and Candidate Drugs Associated with a Hoxa Cluster-Dependency Model of Leukemia

High expression of the HOXA cluster correlates with poor clinical outcome in acute myeloid leukemias, particularly those harboring rearrangements of the mixed-lineage-leukemia gene (MLLr). Whilst decreased HOXA expression acts as a readout for candidate experimental therapies, the necessity of the HOXA cluster for leukemia maintenance has not been fully explored. Primary leukemias were generated in hematopoietic stem/progenitor cells from Cre responsive transgenic mice for conditional deletion of the Hoxa locus. Hoxa deletion resulted in reduced proliferation and colony formation in which surviving leukemic cells retained at least one copy of the Hoxa cluster, indicating dependency. Comparative transcriptome analysis of Hoxa wild type and deleted leukemic cells identified a unique gene signature associated with key pathways including transcriptional mis-regulation in cancer, the Fanconi anemia pathway and cell cycle progression. Further bioinformatics analysis of the gene signature identified a number of candidate FDA-approved drugs for potential repurposing in high HOXA expressing cancers including MLLr leukemias. Together these findings support dependency for an MLLr leukemia on Hoxa expression and identified candidate drugs for further therapeutic evaluation.

In vitro activity, ultrastructural studies and in silico pharmacokinetic properties of indol-3-yl-thiosemicarbazones derivatives and analogues against juvenile and adult worms of S. mansoni

The present work aimed to carry out in vitro biological assays of indol-3-yl derivatives thiosemicarbazones (2a-e) and 4-thiazolidinones (3a-d) against juvenile and adult worms of S. mansoni, as well as the in silico determination of pharmacokinetic parameters for the prediction of the oral bioavailability of these derivatives. All compounds were initially screened at a concentration of 200 μM against S. mansoni adult worms and the results evidenced the good activity of compounds 2b, 2d and 3b, which caused 100% mortality after 24, 48 and 72 h, respectively. Subsequent studies with these same compounds revealed that compound 2b was able to reduce the viability of the parasites by 85% and 83% at concentrations of 200 and 100 μM, respectively. In relation to the juvenile worms, all compounds (2b, 2d and 3b) were able to cause mortality, but compound 2b demonstrated better activity causing 100% mortality in 48 h. Additionally, it was possible to observe reduction in the viability of juvenile worms of 85%, 81% and 64% at concentrations of 200, 100 and 50 μM, respectively. Several ultrastructural damages were observed when adult and juvenile S. mansoni worms were exposed to compound 2b (200 μM) that was characterized by extensive destruction by the integument, which may justify the mortality rate of cultured parasites. In the DNA interaction assay, fragmentation of the genetic material of adult worms when treated with compound 2b (200 μM) was evidenced, indicating the apoptosis process as mechanism of parasite death. Regarding pharmacokinetic properties, all derivatives are according to the required parameters, predicting good oral bioavailability for the studied compounds. The results presented in this study reveal the good activity of compound 2b in both adult and juvenile worms of S. mansoni, pointing this compound as promising in the development of further studies on schistosomicidal activity.

Emetine exhibits anticancer activity in breast cancer cells as an antagonist of Wnt/β‑catenin signaling

Emetine, an amoebicidal drug, exerts potent anticancer activity against various solid tumors, however, the underlying molecular mechanism remains unclear. In the present study, the effects of emetine were investigated on various proteins involved in the Wnt/β‑catenin signaling pathway, which has been linked to various human cancers. It was revealed that emetine blocked Wnt/β‑catenin signaling by targeting components of this pathway, including the low‑density lipoprotein‑receptor‑related protein 6 (LRP6) and disheveled (DVL). Moreover, nanomolar concentrations of emetine decreased phosphorylation of these proteins and suppressed the expression of Wnt target genes, including fibronectin, frizzled‑7 (Fzd7), c‑Myc, Nanog and CD133 in MDA‑MB‑231 and MDA‑MB‑468 breast cancer cells. Additionally, emetine treatment induced apoptosis and suppressed the viability, migration, invasion, and sphere formation of breast cancer cells. Collectively the present results indicated that emetine antagonizes Wnt/β‑catenin signaling, providing insight into the molecular mechanism underlying the anticancer activity of emetine.

Identification of microR-106b as a prognostic biomarker of p53-like bladder cancers by ActMiR

Bladder cancers can be categorized into subtypes according to gene expression patterns. P53-like muscle-invasive bladder cancers are generally resistant to cisplatin-based chemotherapy, but exhibit heterogeneous clinical outcomes with a prognosis intermediate to that of the luminal and basal subtypes. The optimal approach to p53-like tumors remains poorly defined and better means to risk-stratify such tumors and identification of novel therapeutic targets is urgently needed. MicroRNAs (miRNAs) play a key role in cancer, both in tumorigenesis and tumor progression. In the past few years, miRNA expression signatures have been reported as prognostic biomarkers in different tumor types including bladder cancer. However, miRNA’s expression does not always correlate well with its activity. We previously developed ActMiR, a computational method for explicitly inferring miRNA activities. We applied ActMiR to The Cancer Genome Atlas (TCGA) bladder cancer data set and identified the activities of miR-106b-5p and miR-532-3p as potential prognostic markers of the p53-like subtype, and validated them in three independent bladder cancer data sets. Especially, higher miR-106b-5p activity was consistently associated with better survival in these data sets. Furthermore, we experimentally validated causal relationships between miR-106-5p and its predicted target genes in p53-like cell line HT1197. HT1197 cells treated with the miR-106b-5p-specific inhibitor were more invasive while cells treated with the miR-106b-5p-specific mimic were less invasive than corresponding controls. Altogether, our results suggest that miR-106b-5p activity can categorize p53-like bladder tumors into more and less-favorable prognostic groups, which provides critical information for personalizing treatment option for p53-like bladder cancers.

Translation inhibition corrects aberrant localization of mutant alanine-glyoxylate aminotransferase: possible therapeutic approach for hyperoxaluria

Primary hyperoxaluria type 1 is a severe kidney stone disease caused by abnormalities of the peroxisomal alanine-glyoxylate aminotransferase (AGT). The most frequent mutation G170R results in aberrant mitochondrial localization of the active enzyme. To evaluate the population of peroxisome-localized AGT, we developed a quantitative Glow-AGT assay based on the self-assembly split-GFP approach and used it to identify drugs that can correct mislocalization of the mutant protein. In line with previous reports, the Glow-AGT assay showed that mitochondrial transport inhibitors DECA and monensin increased peroxisomal localization of the mutant. Here, we demonstrate that prolonged treatment with the translation elongation inhibitor emetine, a medicinal alkaloid used in treatment of amoebiasis, corrected G170R-AGT mislocalization. Furthermore, emetine reduced the augmented oxalate level in culture media of patient-derived hepatocytes bearing the G170R mutation. A distinct translation inhibitor GC7 had a similar effect on the mutant Glow-AGT relocalization indicating that mild translation inhibition is a promising therapeutic approach for primary hyperoxaluria type 1 caused by AGT misfolding/mistargeting.

KEY MESSAGES

• There is no effective conservative treatment to decrease oxalate production in PH1 patients. • Chemical chaperones rescue mislocalization of mutant AGT and reduce oxalate levels. • We have developed an assay for precise monitoring of the peroxisomal AGT. • Inhibition of translation by emetine reroutes the mutant protein to peroxisome. • Mild translation inhibition is a promising cure for conformational disorders.

Overcoming adaptive resistance in mucoepidermoid carcinoma through inhibition of the IKK-β/IκBα/NFκB axis

Patients with mucoepidermoid carcinoma (MEC) experience low survival rates and high morbidity following treatment, yet the intrinsic resistance of MEC cells to ionizing radiation (IR) and the mechanisms underlying acquired resistance remain unexplored. Herein, we demonstrated that low doses of IR intrinsically activated NFκB in resistant MEC cell lines. Moreover, resistance was significantly enhanced in IR-sensitive cell lines when NFκB pathway was stimulated. Pharmacological inhibition of the IKK-β/IκBα/NFκB axis, using a single dose of FDA-approved Emetine, led to a striking sensitization of MEC cells to IR and a reduction in cancer stem cells. We achieved a major step towards better understanding the basic mechanisms involved in IR-adaptive resistance in MEC cell lines and how to efficiently overcome this critical problem.

Targeting histone deacetylase and NFκB signaling as a novel therapy for Mucoepidermoid Carcinomas

Malignancies from the salivary glands are rare and represent 11% of all cancers from the oropharyngeal anatomical area. Mucoepidermoid Carcinomas (MEC) is the most common malignancy from the salivary glands. Low survival rates of high-grade Mucoepidermoid Carcinomas (MEC) are particularly associated with the presence of positive lymph nodes, extracapsular lymph node spread, and perineural invasion. Most recently, the presence of cancer stem cells (CSC), and the activation of the NFκB signaling pathway have been suggested as cues for an acquired resistance phenotype. We have previously shown that NFκB signaling is very active in MEC tumors. Herein, we explore the efficacy of NFκB inhibition in combination with class I and II HDAC inhibitor to deplete the population of CSC and to destroy MEC tumor cells. Our finding suggests that disruption of NFκB signaling along with the administration of HDAC inhibitors constitute an effective strategy to manage MEC tumors.

The alkaloid emetine sensitizes ovarian carcinoma cells to cisplatin through downregulation of bcl-xL

Cisplatin and its platinum derivatives are first-line chemotherapeutic agents in the treatment of ovarian cancer. However, chemoresistance is the leading cause of therapeutic failure and is responsible for the poor overall survival rate. Here, we describe that emetine, a natural alkaloid used as an anti-amoebiasis drug, sensitized ovarian carcinoma cells to apoptosis induced by cisplatin. The single administration of cisplatin or emetine had a weak effect on cell death. However, co-treatment of cisplatin and emetine remarkably induced apoptosis and reduced the colony formation of ovarian carcinoma cells. Moreover, we showed that apoptosis induced by the combination of cisplatin and emetine was dependent on the activation of caspases -3, -7 and -8. As to the mechanism, downregulation of bcl-xL by emetine was shown to be responsible for enhancing the sensitivity of ovarian cancer cells to cisplatin. These findings suggest that the combination of cisplatin and emetine might be a promising treatment for ovarian cancer.