The role of cordycepin in cancer treatment via induction or inhibition of apoptosis: implication of polyadenylation in a cell type specific manner

Pharmacological and therapeutic potentials of cordycepin in hematological malignancies

Hematological malignancies(HMs) are highly heterogeneous diseases with globally rising incidence. Despite major improvements in the management of HMs, conventional therapies have limited efficacy, and relapses with high mortality rates are still frequent. Cordycepin, a nucleoside analog extracted from Cordyceps species, represents a wide range of therapeutic effects, including anti-inflammatory, anti-tumor, and anti-metastatic activities. Cordycepin induces apoptosis in different subtypes of HMs by triggering adenosine receptors, death receptors, and several vital signaling pathways such as MAPK, ERK, PI3K, AKT, and GSK-3β/β-catenin. This review article summarizes the impact of utilizing cordycepin on HMs, and highlights its potential as a promising avenue for future cancer research based on evidence from in vitro and in vivo studies, as well as clinical trials.

Death Receptor DR5 as a Proviral Factor for Viral Entry and Replication of Coronavirus PEDV

Porcine epidemic diarrhea virus (PEDV), a member of Coronaviridae, causes high mortality in newborn piglets, and has caused significant economic losses in the pig industry. PEDV infection can induce apoptosis, both caspase-dependent and caspase-independent, but the details of apoptosis remain clarified. This study investigated the effect of death receptor DR5 on PEDV infection and its relationship with PEDV-induced apoptosis. We found that DR5 knockdown reduced viral mRNA and protein levels of PEDV, and the viral titer decreased from 10^4.5 TCID₅₀ to 10^3.4 TCID₅₀ at 12 hpi. Overexpression of DR5 significantly increased the viral titer. Further studies showed that DR5 facilitates viral replication by regulating caspase-8-dependent apoptosis, and the knockdown of DR5 significantly reduced PEDV-induced apoptosis. Interestingly, we detected a biphasic upregulation expression of DR5 in both Vero cells and piglets in response to PEDV infection. We found that DR5 also facilitates viral entry of PEDV, especially, incubation with DR5 antibody can reduce the PEDV binding to Vero cells. Our study improves the understanding of the mechanism by which PEDV induces apoptosis and provides new insights into the biological function of DR5 in PEDV infection.

Cordyceps militaris Exerts Anticancer Effect on Non-Small Cell Lung Cancer by Inhibiting Hedgehog Signaling via Suppression of TCTN3

This study aimed to investigate the effect of Cordyceps militaris extract on the proliferation and apoptosis of non–small cell lung cancer (NSCLC) cells and determine the underlying mechanisms. We performed a CCK-8 assay to detect cell proliferation, detection of morphological changes through transmission electron microscopy (TEM), annexin V–FITC/PI double staining to analyze apoptosis, and immunoblotting to measure the protein expression of apoptosis and hedgehog signaling–related proteins, with C militaris treated NSCLC cells. In this study, we first found that C militaris reduced the viability and induced morphological disruption in NSCLC cells. The gene expression profiles indicated a reprogramming pattern of genes and transcription factors associated with the action of TCTN3 on NSCLC cells. We also confirmed that the C militaris–induced inhibition of TCTN3 expression affected the hedgehog signaling pathway. Immunoblotting indicated that C militaris–mediated TCTN3 downregulation induced apoptosis in NSCLC cells, involved in the serial activation of caspases. Moreover, we demonstrated that the C militaris negatively modulated GLI1 transcriptional activity by suppressing SMO/PTCH1 signaling, which affects the intrinsic apoptotic pathway. When hedgehog binds to the PTCH1, SMO dissociates from PTCH1 inhibition at cilia. As a result, the active GLI1 translocates to the nucleus. C militaris clearly suppressed GLI1 nuclear translocation, leading to Bcl-2 and Bcl-xL down-regulation. These results suggested that C militaris induced NSCLC cell apoptosis, possibly through the downregulation of SMO/PTCH1 signaling and GLI1 activation via inhibition of TCTN3. Taken together, our findings provide new insights into the treatment of NSCLC using C militaris.

Potential and promising anticancer drugs from adenosine and its analogs

In recent years, many studies have shown that adenosine has efficacy for treating cancer. More importantly, some adenosine analogs have been successfully marketed to fulfill anticancer purposes. In this review, we summarize the anticancer effects of adenosine and its analogs in clinical trials and preclinical studies, with focus on their anticancer mechanisms. In addition, we link the anticancer activities of adenosine analogs with their structures through structure-activity relationship (SAR) analysis, and highlight additional promising anticancer drug candidates. We hope that this review will be of help in understanding the importance of adenosine and its analogs with anticancer activities and directing future research and development of such compounds.

Cordycepin in Anticancer Research: Molecular Mechanism of Therapeutic Effects

BACKGROUND

Cordycepin is a nucleotide analogue from Cordyceps mushrooms, which occupies a notable place in traditional medicine.

OBJECTIVE

In this review article, we have discussed the recent findings on the molecular aspects of cordycepin interactions with its recognized cellular targets, and possible mechanisms of its anticancer activity.

METHODS

We have explored databases like pubmed, google scholar, scopus and web of science for the update information on cordycepin and mechanisms of its anticancer activity, and reviewed in this study.

RESULTS

Cordycepin has been widely recognized for its therapeutic potential against many types of cancers by various mechanisms. More specifically, cordycepin can induce apoptosis, resist cell cycle and cause DNA damage in cancer cells, and thus kill or control cancer cell growth. Also cordycepin can induce autophagy and modulate immune system. Furthermore, cordycepin also inhibits tumor metastasis. Although many success stories of cordycepin in anticancer research in vitro and in animal model, and there is no successful clinical trial yet.

CONCLUSION

Ongoing research studies have reported highly potential anticancer activities of cordycepin with numerous molecular mechanisms. The in vitro and in vivo success of cordycepin in anticancer research might influence the clinical trials of cordycepin, and this molecule might be used for development of future cancer drug.

PI3K-AKT-mTOR and NFκB Pathways in Ovarian Cancer: Implications for Targeted Therapeutics

Ovarian cancer is the most lethal gynecologic malignancy in the United States, with an estimated 22,530 new cases and 13,980 deaths in 2019. Recent studies have indicated that the phosphoinositol 3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), as well as the nuclear factor-κ light chain enhancer of activated B cells (NFκB) pathways are highly mutated and/or hyper-activated in a majority of ovarian cancer patients, and are associated with advanced grade and stage disease and poor prognosis. In this review, we will investigate PI3K/AKT/mTOR and their interconnection with NFκB pathway in ovarian cancer cells.

The Anticancer Properties of Cordycepin and Their Underlying Mechanisms

Cordyceps is a genus of ascomycete fungi that has been used for traditional herbal remedies. It contains various bioactive ingredients including cordycepin. Cordycepin, also known as 3-deoxyadenosine, is a major compound and has been suggested to have anticancer potential. The treatment of various cancer cells with cordycepin in effectively induces cell death and retards their cancerous properties. However, the underlying mechanism is not fully understood. Recent evidence has shed light on the molecular pathways involving cysteine-aspartic proteases (caspases), mitogen-activated protein kinases (MAPKs), and glycogen synthase kinase 3 beta (GSK-3β). Furthermore, the pathways are mediated by putative receptors, such as adenosine receptors (ADORAs), death receptors (DRs), and the epidermal growth factor receptor (EGFR). This review provides the molecular mechanisms by which cordycepin functions as a singular or combinational anticancer therapeutic agent.

Cordycepin induces apoptosis of human ovarian cancer cells by inhibiting CCL5-mediated Akt/NF-κB signaling pathway

The chemokine, CCL5, is a key mediator for the recruitment of immune cells into tumors and tissues. Akt/NF-κB signaling is significantly activated by CCL5. However, the role of NF-κB inactivation in apoptosis induced by negative regulation of CCL5 remains unclear. Here, we analyzed the effect of cordycepin on NF-κB activity in SKOV-3 cells and found that cordycepin-mediated inhibition of NF-κB signaling induced apoptosis in SKOV-3 cells via the serial activation of caspases. In addition, immune-blotting analysis showed that CCL5 is highly expressed in SKOV-3 cells. In addition to activating caspases, we show that, cordycepin prevents TNF-α-induced increase in CCL5, Akt, NF-κB, and c-FLIP_L activation and that CCL5 siRNA could inhibit Akt/NF-κB signaling. Moreover, cordycepin negatively regulated the TNF-α-mediated IκB/NF-κB pathway and c-FLIP_L activation to promote JNK phosphorylation, resulting in caspase-3 activation and apoptosis. Also, we show that c-FLIP_L is rapidly lost in NF-κB activation-deficient. siRNA mediated c-FLIP inhibition increased JNK. SP600125, a selective JNK inhibitor, downregulated p-JNK expression in cordycepin-treated SKOV-3 cells, leading to suppression of cordycepin-induced apoptosis. Thus, these results indicate that cordycepin inhibits CCL5-mediated Akt/NF-κB signaling, which upregulates caspase-3 activation in SKOV-3 cells, supporting the potential of cordycepin as a therapeutic agent for ovarian cancer.

The inhibitory effect of Cordycepin on the proliferation of cisplatin-resistant A549 lung cancer cells

The goal of this study is to determine the anti-cancer mechanism of Cordycepin in A549 Cisplatin-Resistance (CR) lung cancer cells. Cordycepin inhibited the viability of A549CR cells in a dose-dependent manner. The cell inhibition was due to induction of apoptosis in the cells treated with Cordycepin by activation of caspase -3, -8 and -9 activities. The cell cycle analysis showed that accumulation of Sub G1 was observed in Cordycepin-treated with A549CR lung cancer cells. Based on the data of expression profile analysis of cell signaling proteins using IPS-FPAA, H-Ras was down-regulated in Cordycepin-treated A549CR cells. Collectively, anti-proliferative function of Cordycepin was due to stimulation of the cell apoptosis and the cell cycle arrest via caspases activation and down-regulation of H-Ras.

Cordycepin induces apoptosis in human liver cancer HepG2 cells through extrinsic and intrinsic signaling pathways

Cordycepin, also termed 3'-deoxyadenosine, is a nucleoside analogue from Cordyceps sinensis and has been reported to demonstrate numerous biological and pharmacological properties. Our previous study illustrated that the anti-tumor effect of cordycepin may be associated with apoptosis. In the present study, the apoptotic effect of cordycepin on HepG2 cells was investigated using 4',6-diamidino-2-phenylindole, tetraethylbenzimidazolylcarbocyanine iodide and propidium iodide staining analysis and flow cytometry. The results showed that cordycepin exhibited the ability to inhibit HepG2 cells in a time- and dose-dependent manner when cells produced typical apoptotic morphological changes, including chromatin condensation, the accumulation of sub-G1 cells and change mitochondrial permeability. A potential mechanism for cordycepin-induced apoptosis of human liver cancer HepG2 cells may occur through the extrinsic signaling pathway mediated by the transmembrane Fas-associated with death domain protein. Apoptosis was also associated with Bcl-2 family protein regulation, leading to altered mitochondrial membrane permeability and resulting in the release of cytochrome c into the cytosol. The activation of the caspase cascade is responsible for the execution of apoptosis. In conclusion, cordycepin-induced apoptosis in HepG2 cells involved the extrinsic and intrinsic signaling pathway and was primarily regulated by the Bcl-2 family proteins.

Proapoptotic Role of Potassium Ions in Liver Cells

Potassium channels are transmembrane proteins that selectively promote the infiltration of potassium ions. The significance of these channels for tumor biology has become obvious. However, the effects of potassium ions on the tumor or normal cells have seldom been studied. To address this problem, we studied the biological effects of L02 and HepG2 cells with ectogenous potassium ions. Cell proliferation, cell cycle, and apoptosis rate were analyzed. Our results indicated that potassium ions inhibited proliferation of L02 and HepG2 cells and promoted their apoptosis. Potassium ions induced apoptosis through regulating Bcl-2 family members and depolarized the mitochondrial membrane, especially for HepG2 cell. These biological effects were associated with channel protein HERG. By facilitating expression of channel protein HERG, potassium ions may prevent it from being shunted to procancerous pathways by inducing apoptosis. These results demonstrated that potassium ions may be a key regulator of liver cell function. Thus, our findings suggest that potassium ions could inhibit tumorigenesis through inducing apoptosis of hepatoma cells by upregulating potassium ions transport channel proteins HERG and VDAC1.

Cordycepin increases radiosensitivity in cervical cancer cells by overriding or prolonging radiation-induced G2/M arrest

Cordycepin (3-deoxyadenosine) has many pharmacological activities. We studied the radiosensitising effect of cordycepin and the underlying mechanisms relating to cell cycle changes in two human uterine cervical cancer cell lines, ME180 and HeLa cells. Cordycepin produced concentration- and time-dependent reductions in cell viability with more pronounced effects in ME180 cells. Cells pre-treated with cordycepin showed lower cell survival than those exposed to irradiation only. Radiation-induced expression of the histone, γ-H2AX, and apoptosis were also increased following cordycepin pre-treatment. In ME180 cells, pre-treatment with cordycepin reduced radiation-induced G2/M arrest and this G2/M checkpoint override was sustained for longer than in HeLa cells, where G2/M arrest was observed earlier and more briefly, the number of HeLa cells in the G2/M phase was subsequently increased. Cordycepin produced different effects on the expression of p53 and cell cycle checkpoint proteins in these two cell lines. It can be assumed that the mechanism underlying cordycepin-mediated radiosensitisation involves multiple effects that are primarily based on the induction of p53-mediated apoptosis and modulation of the expression of cell cycle checkpoint molecules.

Cordycepin induces S phase arrest and apoptosis in human gallbladder cancer cells

Gallbladder cancer is the most common malignant tumor of the biliary tract, and this condition has a rather dismal prognosis, with an extremely low five-year survival rate. To improve the outcome of unresectable and recurrent gallbladder cancer, it is necessary to develop new effective treatments and drugs. The purpose of the present study was to evaluate the effects of cordycepin on human gallbladder cells and uncover the molecular mechanisms responsible for these effects. The Cell Counting Kit-8 (CCK-8) and colony formation assays revealed that cordycepin affected the viability and proliferation of human gallbladder cancer cells in a dose- and time-dependent manner. Flow cytometric analysis showed that cordycepin induced S phase arrest in human gallbladder cancer cell lines(NOZ and GBC-SD cells). Cordycepin-induced apoptosis was observed using an Annexin V/propidium iodide (PI) double-staining assay, and the mitochondrial membrane potential (ΔΨm) decreased in a dose-dependent manner. Additionally, western blot analysis revealed the upregulation of cleaved-caspase-3, cleaved-caspase-9, cleaved-PARP and Bax and the downregulation of Bcl-2, cyclin A and Cdk-2 in cordycepin-treated cells. Moreover, cordycepin inhibited tumor growth in nude mice bearing NOZ tumors. Our results indicate that this drug may represent an effective treatment for gallbladder carcinoma.

Cordycepin inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α production via activating amp-activated protein kinase (AMPK) signaling

Tumor necrosis factor (TNF)-α is elevated during the acute phase of Kawasaki disease (KD), which damages vascular endothelial cells to cause systemic vasculitis. In the current study, we investigated the potential role of cordycepin on TNFα expression in both lipopolysaccharide (LPS)-stimulated macrophages and ex vivo cultured peripheral blood mononuclear cells (PBMCs) of KD patients. We found that cordycepin significantly suppressed LPS-induced TNFα expression and production in mouse macrophages (RAW 264.7 cells and bone marrow-derived macrophages (BMDMs)). Meanwhile, cordycepin alleviated TNFα production in KD patients’ PBMCs. PBMCs from healthy controls had a much lower level of basal TNF-α content than that of KD patients. LPS-induced TNF-α production in healthy controls’ PBMCs was also inhibited by cordycepin. For the mechanism study, we discovered that cordycepin activated AMP-activated protein kinase (AMPK) signaling in both KD patients’ PBMCs and LPS-stimulated macrophages, which mediated cordycepin-induced inhibition against TNFα production. AMPK inhibition by its inhibitor (compound C) or by siRNA depletion alleviated cordycepin’s effect on TNFα production. Further, we found that cordycepin inhibited reactive oxygen species (ROS) production and nuclear factor kappa B (NF-κB) activation in LPS-stimulate RAW 264.7 cells or healthy controls’ PBMCs. PBMCs of KD patients showed higher basal level of ROS and NF-κB activation, which was also inhibited by cordycepin co-treatment. In conclusion, our data showed that cordycepin inhibited TNFα production, which was associated with AMPK activation as well as ROS and NF-κB inhibition. The results of this study should have significant translational relevance in managing this devastating disease.

Involvement of autophagy in cordycepin-induced apoptosis in human prostate carcinoma LNCaP cells

Cordycepin, an active ingredient of the insect fungus Cordyceps spp., shows strong antioxidant and anticancer activities. Several molecular mechanisms have been attributed to its inhibitory effects on a wide range of tumor cells; however, the mechanism causing cancer cell death is still obscure. For the current study, we further investigated the mechanism responsible for targeting cordycepin-induced cell death and its association with autophagy in human prostate carcinoma LNCaP cells. Our results show that cordycepin resulted in significant reduction in LNCaP cell survival by inducing apoptotic cell death. Cordycepin treatment caused a dose-dependent increase of pro-apoptotic Bax and decrease of anti-apoptotic Bcl-2, triggering collapse of the mitochondrial membrane potential and activation of caspase-9 and -3. Cordycepin-induced cell death was also associated with induction of Fas and death receptor 5, activation of caspase-8, and truncation of Bid (tBid), suggesting that tBid might serve to connect activation of both the mitochondrial-mediated intrinsic and death receptor-mediated extrinsic apoptotic pathways. The general caspase inhibitor, z-VAD-fmk, completely abolished cordycepin-induced cell death, demonstrating that cordycepin-induced apoptosis was dependent on the activation of caspases. Cordycepin also stimulated autophagy, which was evidenced by an increase in microtubule-associated protein light chain-3 (LC3) puncta, accumulation of LC3-II, and elevation of autophagic flux; however, blockage of autophagic flux by the autophagic inhibitor bafilomycin A1 promoted cell-switching to apoptotic cell death. These findings suggest that cordycepin-induced autophagy functions as a survival mechanism and that autophagy is a potential strategy for treating prostate cancer that is resistant to pro-apoptotic therapeutics.

Determinants and implications of mRNA poly(A) tail size--does this protein make my tail look big?

While the phenomenon of polyadenylation has been well-studied, the dynamics of poly(A) tail size and its impact on transcript function and cell biology are less well-appreciated. The goal of this review is to encourage readers to view the poly(A) tail as a dynamic, changeable aspect of a transcript rather than a simple static entity that marks the 3' end of an mRNA. This could open up new angles of regulation in the post-transcriptional control of gene expression throughout development, differentiation and cancer.

Optimization of fermentation conditions and purification of cordycepin from Cordyceps militaris

The fermentation medium and conditions for the production of cordycepin were optimized in static culture using single-factor experiments, Placket-Burman design, a central composite design, and response surface methodology. Among seven variables including temperature, pH, and the concentrations of glucose, tryptone, yeast extract, KH₂PO₄, and MgSO₄ · 7H₂O, temperature and the concentrations of yeast extract and tryptone were found to be the important factors that significantly affected cordycepin production. The optimized medium consisted of yeast extract 9.00 g/L and tryptone 17.10 g/L, while the optimized culture conditions consisted of seed age 3 days, with an inoculum size of 10% and incubation temperature of 27.1°C. A maximum cordycepin yield of 7.35 g/L was achieved in a 5-L fermenter under the optimized conditions. Next, cordycepin was partially purified and determined. The resulting product showed 90.54% high-performance liquid chromatography (HPLC)-ultraviolet (UV) purity. Therefore, cordycepin was applied to a cell viability assay on SH-SY5Y cells and RM-1 cells. Cordycepin can inhibit the proliferation of RM-1 cells with IC₅₀ of 133 µmol/L, but it has no inhibitory effect on SH-SY5Y cells. Supplemental materials are available for this article.

Effects of cordycepin on HepG2 and EA.hy926 cells: Potential antiproliferative, antimetastatic and anti-angiogenic effects on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor and accumulating evidence suggests that angiogenesis plays an important role in HCC development. Cordycepin, also known as 3′-deoxyadenosine, is a derivative of adenosine, and numerous cellular enzymes cannot differentiate the two. The aim of the present study was to determine whether cordycepin regulates proliferation, migration and angiogenesis in a human umbilical vein endothelial cell line (EA.hy926) and in a hepatocellular carcinoma cell line (HepG2). MTT was used to assess cell proliferation. Apoptosis was analyzed by flow cytometry (propidium iodide staining). Transwell and wound healing assays were used to analyze the migration and invasion of HepG2 and EA.hy926 cells. Angiogenesis in EA.hy926 cells was assessed using a tube formation assay. Cordycepin strongly suppressed HepG2 and EA.hy926 cell proliferation in a dose- and time-dependent manner. Cordycepin induced EA.hy926 cell apoptosis in a dose-dependent manner (2,000 μg/ml: 50.20±1.55% vs. 0 μg/ml: 2.62±0.19%; P<0.01). Cordycepin inhibited EA.hy926 cell migration (percentage of wound healing area, 2,000 μg/ml: 3.45±0.29% vs. 0 μg/ml: 85.48±0.84%; P<0.05), as well as tube formation (total length of tubular structure, 1,000 μg/ml: 107±39 μm vs. 0 μg/ml: 936±56 μm; P<0.05). Cordycepin also efficiently inhibited HepG2 cell invasion and migration. High-performance liquid chromatography analysis of the cytosol from EA.hy926 cells showed that cordycepin was stable for 3 h. In conclusion, cordycepin not only inhibited human HepG2 cell proliferation and invasion, but also induced apoptosis and inhibited migration and angiogenesis in vascular endothelial cells, suggesting that cordycepin may be used as a novel anti-angiogenic therapy in HCC.

Cordycepin-mediated transcriptional regulation of human GD3 synthase (hST8Sia I) in human neuroblastoma SK-N-BE(2)-C cells

In the present study, we firstly found that cordycepin elevated the gene expression of the human GD3 synthase (hST8Sia I) in human neuroblastoma SK-N-BE(2)-C cells. To elucidate the mechanism underlying the upregulation of hST8Sia I gene expression in cordycepin-treated SK-N-BE(2)-C cells, functional characterization of the promoter region of the hST8Sia I gene was performed. Analysis of promoter activity using varying lengths of 5'-flanking region showed a dramatic increase by cordycepin in the -1146 to -646 region, which contains putative binding sites for transcription factors c-Ets-1, CREB, AP-1, and NF-κB. Site-directed mutagenesis for these binding sites and chromatin immunoprecipitation assay revealed that the NF-κB binding site at -731 to -722 is essential for the cordycepin-induced expression of the hST8Sia I in SK-N-BE(2)-C cells. Moreover, the hST8Sia I expression induced by cordycepin was significantly repressed by pyrrolidinedithiocarbamate, an inhibitor of NF-κB. These results suggested that cordycepin induces upregulation of hST8Sia I gene expression through NF-κB activation in SK-N-BE(2)-C cells.

A novel synthetic analog of Militarin, MA-1 induces mitochondrial dependent apoptosis by ROS generation in human lung cancer cells

A synthetic Militarin analog-1[(2R,3R,4R,5R)-1,6-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy) hexane-2,3,4,5-tetraol] is a novel derivative of constituents from Cordyceps militaris, which has been used to treat a variety of chronic diseases including inflammation, diabetes, hyperglycemia and cancers. Here, we report for the first time the synthesis of Militarin analog-1 (MA-1) and the apoptotic mechanism of MA-1 against human lung cancer cell lines. Treatment with MA-1 significantly inhibited the viability of 3 human lung cancer cell lines. The inhibition of viability and growth in MA-1-treated A549 cells with an IC50 of 5μM were mediated through apoptosis induction, as demonstrated by an increase in DNA fragmentation, sub-G0/G1-DNA fraction, nuclear condensation, and phosphatidylserine exposure. The apoptotic cell death caused mitochondrial membrane permeabilization through regulation of expression of the Bcl-2 family proteins, leading to cytochrome c release in a time-dependent manner. Subsequently, the final stage of apoptosis, activation of caspase-9/-3 and cleavage of poly (ADP ribose) polymerase, was induced. Furthermore, A549 lung cancer cells were more responsive to MA-1 than a bronchial epithelial cell line (BEAS-2B), involving the rapid generation of reactive oxygen species (ROS), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activation. The pharmacological inhibition of ROS generation and JNK/p38 MAPK exhibited attenuated DNA fragmentation in MA-1-induced apoptosis. Oral administration of MA-1 also retarded growth of A549 orthotopic xenografts. In conclusion, the present study indicates that the new synthetic derivative MA-1 triggers mitochondrial apoptosis through ROS generation and regulation of MAPKs and may be a potent therapeutic agent against human lung cancer.

Alterations in polyadenylation and its implications for endocrine disease

INTRODUCTION

Polyadenylation is the process in which the pre-mRNA is cleaved at the poly(A) site and a poly(A) tail is added - a process necessary for normal mRNA formation. Genes with multiple poly(A) sites can undergo alternative polyadenylation (APA), producing distinct mRNA isoforms with different 3' untranslated regions (3' UTRs) and in some cases different coding regions. Two thirds of all human genes undergo APA. The efficiency of the polyadenylation process regulates gene expression and APA plays an important part in post-transcriptional regulation, as the 3' UTR contains various cis-elements associated with post-transcriptional regulation, such as target sites for micro-RNAs and RNA-binding proteins. Implications of alterations in polyadenylation for endocrine disease: Alterations in polyadenylation have been found to be causative of neonatal diabetes and IPEX (immune dysfunction, polyendocrinopathy, enteropathy, X-linked) and to be associated with type I and II diabetes, pre-eclampsia, fragile X-associated premature ovarian insufficiency, ectopic Cushing syndrome, and many cancer diseases, including several types of endocrine tumor diseases.

PERSPECTIVES

Recent developments in high-throughput sequencing have made it possible to characterize polyadenylation genome-wide. Antisense elements inhibiting or enhancing specific poly(A) site usage can induce desired alterations in polyadenylation, and thus hold the promise of new therapeutic approaches.

SUMMARY

This review gives a detailed description of alterations in polyadenylation in endocrine disease, an overview of the current literature on polyadenylation and summarizes the clinical implications of the current state of research in this field.

Evidence That Naturopathic Therapy Including Cordyceps sinensis Prolongs Survival of Patients With Hepatocellular Carcinoma

Hypothesis. Naturopathic treatment will benefit patients with hepatocellular carcinoma (HCC). Study design. Retrospective analysis of case series of HCC patients treated with naturopathic agents. Methods. HCC was diagnosed by dynamic computed tomography (CT) imaging and α-fetoprotein (AFP) or PIVKA II, or by histology. Tumor staging was determined by CT. A modified Childs–Pugh scoring was used to assess liver disease. Patients were treated with orally administered combinations of 12 naturopathic agents. Patients were monitored clinically and by CT tumor imaging, serial tumor markers, and liver function tests. Results. Patient characteristics: 101 patients with HCC (67 men and 34 women, age 67.2 ± 8.8 years) were treated for a median of 13.4 months (range 0.8-100.8). Of these 84% had cirrhosis, 63% had hepatitis C virus, 18% had hepatitis B virus, 1% had both, and 9% had metastatic disease. Median modified Childs–Pugh score was 6 (range 3-13). Barcelona Clinic Liver Cancer tumor stages of 0, A, B, C, and D were found in 36%, 25%, 20%, 14%, and 6%, respectively. Median AFP was 40 (range 0-311,000). Median PIVKA II was 59 (0–378,000). Previous treatment was included none (27%), resection with relapse (20%), transarterial chemoembolization (50%), radiofrequency ablation (28%), percutaneous ethanol injection therapy (15%), chemotherapy (14%). Outcomes: Initial treatment was with 2.6 ± 0.8 agents (range 2-4). Overall, patients were treated with 3.7 ± 1.2 agents (range 2-7). There was a significant correlation between number of agents administered and survival ( P < .0001). Patients treated with ≥4 agents survived significantly longer than patients treated with ≤3 agents (40.2 vs 6.4 months, P < .0001). This difference could not be attributed to statistically significant differences in severity of liver disease or tumor stage, delay in treatment, previous treatment, concurrent nondrug treatment, or censoring effects. The greatest effect was seen in patients treated with at least 4 agents that included Cordyceps sinensis. This prolonged survival was without toxic side effects and appeared to potentiate the survival benefit of conventional therapy. Conclusion. Treatment of HCC with a regimen of ≥4 agents prepared from natural products was associated with prolonged survival in a substantial portion of patients. The data provide level II evidence for the efficacy of naturopathic therapy in HCC.

MLH1-deficient HCT116 colon tumor cells exhibit resistance to the cytostatic and cytotoxic effect of the poly(A) polymerase inhibitor cordycepin (3'-deoxyadenosine) in vitro

Cordycepin (3'-deoxyadenosine) is an inhibitor of poly(A) polymerase (PAP), an enzyme crucial to mRNA 3'-end processing, which produces the shortening of poly(A) tails, leading to the destabilization of mRNAs. Cordycepin inhibits proliferation and induces apoptosis in tumor cells, indicating its antitumor activity. Defective 3'-end processing is associated with hypersensitivity to UV treatment. We investigated the effects of cordycepin on proliferation and apoptosis in MLH1-deficient and MLH1-proficient HCT116 colon tumor cells. MLH1 is a DNA mismatch repair (MMR) protein involved in the processing of damaged DNA. Cells with defective MMR show resistance to certain anticancer drugs. The results showed that MLH1-deficient HCT116 cells are 2-fold less sensitive to the cytostatic effect of cordycepin, as compared to MLH1-proficient cells. This reduced sensitivity to cordycepin in MLH1-deficient cells was associated with reduced upregulation of the cell cycle inhibitor p21. MLH1-deficient cells also exhibited reduced susceptibility to apoptosis upon treatment with cordycepin, as demonstrated by the reduced PARP-1 cleavage. Our findings showed that MLH1-deficient HCT116 colon tumor cells are resistant to the cytostatic and cytotoxic effect of cordycepin, indicating a possible involvement of MMR in mRNA polyadenylation. The findings also suggest that cordycepin is not suitable to therapeutically encounter tumor cells lacking MLH1 expression.

The Effect of Cordycepin on Steroidogenesis and Apoptosis in MA-10 Mouse Leydig Tumor Cells

Cordycepin is a natural pure compound extracted from Cordyceps sinensis (CS). We have demonstrated that CS stimulates steroidogenesis in primary mouse Leydig cell and activates apoptosis in MA-10 mouse Leydig tumor cells. It is highly possible that cordycepin is the main component in CS modulating Leydig cell functions. Thus, our aim was to investigate the steroidogenic and apoptotic effects with potential mechanism of cordycepin on MA-10 mouse Leydig tumor cells. Results showed that cordycepin significantly stimulated progesterone production in dose- and time-dependent manners. Adenosine receptor (AR) subtype agonists were further used to treat MA-10 cells, showing that A₁, A _2A , A _2B , and A₃, AR agonists could stimulate progesterone production. However, StAR promoter activity and protein expression remained of no difference among all cordycepin treatments, suggesting that cordycepin might activate AR, but not stimulated StAR protein to regulate MA-10 cell steroidogenesis. Meanwhile, cordycepin could also induce apoptotic cell death in MA-10 cells. Moreover, four AR subtype agonists induced cell death in a dose-dependent manner, and four AR subtype antagonists could all rescue cell death under cordycepin treatment in MA-10 cells. In conclusion, cordycepin could activate adenosine subtype receptors and simultaneously induce steroidogenesis and apoptosis in MA-10 mouse Leydig tumor cells.

Cordycepin induces apoptosis by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules

OBJECTIVE

To explore the molecular mechanism by which cordycepin inhibits cell proliferation and induces apoptosis of human colorectal cancer cells.

METHODS

Cell counting and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium, inner salt) method were used to monitor the effects of cordycepin on cell proliferation. Flow cytometry (FCM) was used to analyze the effects of cordycepin on the cell cycle progress. Annexin V-fluorescein isothiocyanate (FITC) analysis was used to detect apoptosis at a very early stage. Caspase-Glo was used to determine caspase activity and Western blot was used to measure protein expression levels of c-Jun N-terminal kinase (JNK), p38, and Bcl-2 pro-apoptosis family.

RESULTS

The numbers of viable SW480 and SW620 cells and the proliferation of these cells were significantly reduced with increases in cordycepin concentration (P<0.01). The cell cycle progression of SW480 and SW620 was arrested at the G0/G1 phase by the addition of cordycepin, and apoptosis rates of cordycepin treatments were increased compared with the control group. Cordycepin-treated cells showed phosphatidylserine valgus, suggesting the existence of early apoptosis. Caspase-3/7 and -9 activity significantly increased and the protein expression levels of JNK, p38, and Bax, Bid, Bim, and Puma from Bcl-2 pro-apoptosis molecules also increased after the treatment with cordycepin.

CONCLUSIONS

Cordycepin can inhibit SW480 and SW620 cell proliferation and induce apoptosis. Apoptosis might be induced by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules.

Cordycepin induces apoptosis of CGTH W-2 thyroid carcinoma cells through the calcium-calpain-caspase 7-PARP pathway

Cordycepin, a nucleoside isolated from Cordyceps sinensis, is an inhibitor of polyadenylation and has an antitumor effect. We used CGTH W-2, a follicular thyroid carcinoma cell line, to study the mechanism of the anticancer effect of cordycepin. Cordycepin decreased cell viability and resulted in apoptosis but not necrosis. Cordycepin increased intracellular calcium levels triggering calpain activation, which led to apoptosis. BAPTA/AM and calpeptin inhibited the cordycepin-induced cleavage of caspase 7 and poly (ADP-ribose) polymerase (PARP), implying an upstream role of calcium and calpain. CGTH W-2 cells expressed four subtypes of adenosine receptors (AR), A1AR, A2AAR, A2BAR, and A3AR. Specific antagonists to AR subtypes all blocked cordycepin-induced apoptosis to different degrees. Small interfering RNA for A1AR and A3AR abrogated cordycepin-induced apoptosis. In conclusion, the cordycepin-induced apoptosis of CGTH W-2 cells is mediated by the calcium-calpain-caspase 7-PARP pathway, and ARs are involved in the apoptotic effect of cordycepin.

Cordycepin Induced MA-10 Mouse Leydig Tumor Cell Apoptosis through Caspase-9 Pathway

In the present study, the apoptotic effect of cordycepin on MA-10 cells, a mouse Leydig tumor cell line, was investigated. Results demonstrated that the number of rounding-up cell increased by cordycepin (10 μM to 5 mM for 24 h), and cells with plasma membrane blebbing could be observed by 100 μM cordycepin. In viability test, MA-10 cell surviving rate significantly decreased as the dosage (10 μM to 5 mM) and duration (3–24 h) of cordycepin treatment increased (P < 0.05). Cordycepin at 100 μM and 1 mM for 24 h treatment induced significant DNA fragmentation (P < 0.05). In addition, the percentage of G1 and G2/M phase cell significantly declined by cordycepin (100 μM and 1 mM) for 24 h treatment, while the percentages of subG1 phase cell increased by 100 μM and/or 1 mM cordycepin in 6, 12 and 24 h treatments (P < 0.05), respectively, which highly suggested that cordycepin induced MA-10 cell apoptosis. In mechanism study with the treatments of caspases, c-Jun NH₂ terminal kinase (JNK) or reactive oxygen species (ROS) inhibitors plus cordycepin for 24 h, only caspases inhibitor suppressed subG1 phase in MA-10 cells. Moreover, western blotting results showed that cordycepin induced caspase-9, -3 and -7 protein expressions, but not caspase-8, in time- and dose-dependent manners. In conclusion, cordycepin induced apoptosis in MA-10 mouse Leydig tumor cells through a caspase-9 and -3 and -7 dependent pathway.

Cordycepin inhibits protein synthesis and cell adhesion through effects on signal transduction

3′-Deoxyadenosine, also known as cordycepin, is a known polyadenylation inhibitor with a large spectrum of biological activities, including anti-proliferative, pro-apoptotic and anti-inflammatory effects. In this study we confirm that cordycepin reduces the length of poly(A) tails, with some mRNAs being much more sensitive than others. The low doses of cordycepin that cause poly(A) changes also reduce the proliferation of NIH3T3 fibroblasts. At higher doses of the drug we observed inhibition of cell attachment and a reduction of focal adhesions. Furthermore, we observed a strong inhibition of total protein synthesis that correlates with an inhibition of mammalian target of rapamycin (mTOR) signaling, as observed by reductions in Akt kinase and 4E-binding protein (4EBP) phosphorylation. In 4EBP knock-out cells, the effect of cordycepin on translation is strongly reduced, confirming the role of this modification. In addition, the AMP-activated kinase (AMPK) was shown to be activated. Inhibition of AMPK prevented translation repression by cordycepin and abolished 4EBP1 dephosphorylation, indicating that the effect of cordycepin on mTOR signaling and protein synthesis is mediated by AMPK activation. We conclude that many of the reported biological effects of cordycepin are likely to be due to its effects on mTOR and AMPK signaling.