Cordyceptin induces apoptosis through repressing hTERT expression and inducing extranuclear export of hTERT

Telomerase Inhibition in the Treatment of Leukemia: A Comprehensive Review

Leukemia, characterized by the uncontrolled proliferation and differentiation blockage of myeloid or lymphoid precursor cells, presents significant therapeutic challenges despite current treatment modalities like chemotherapy and stem cell transplantation. Pursuing novel therapeutic strategies that selectively target leukemic cells is critical for improving patient outcomes. Natural products offer a promising avenue for developing effective chemotherapy and preventive measures against leukemia, providing a rich source of biologically active compounds. Telomerase, a key enzyme involved in chromosome stabilization and mainly active in cancer cells, presents an attractive target for intervention. In this review article, we focus on the anti-leukemic potential of natural substances, emphasizing vitamins (such as A, D, and E) and polyphenols (including curcumin and indole-3-carbinol), which, in combination with telomerase inhibition, demonstrate reduced cytotoxicity compared to conventional chemotherapies. We discuss the role of human telomerase reverse transcriptase (hTERT), particularly its mRNA expression, as a potential therapeutic target, highlighting the promise of natural compounds in leukemia treatment and prevention.

Cordycepin and kinase inhibition in cancer

Cordycepin, a nucleoside from Cordyceps mushrooms, has many beneficial properties for health, including anticancer activities. In cancer cells, cordycepin targets various signaling molecules. Here, we review the possible anticancer mechanisms of cordycepin involving the targeting of kinases. Abnormal kinase expression is involved in cancer development and progression through different molecular mechanisms, including phosphorylation, amplification, genetic mutations, and epigenetic regulation. Research suggests that kinases, such as the c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase (MAPK), AMP kinase (AMPK), phosphoinositide 3-kinase (PI3K)/Akt, extracellular signal-regulated kinase (ERK), mammalian target of rapamycin (mTOR), glycogen synthase kinase (GSK)-3β, and focal adhesion kinase (FAK) pathways, can be targeted by cordycepin and disrupting their activity. Given that kinase inhibitors can have crucial roles in cancer treatment, targeting kinases might be one of the molecular mechanisms involved in the anticancer potential of cordycepin.

Exploring the mechanism of cordycepin combined with doxorubicin in treating glioblastoma based on network pharmacology and biological verification

BACKGROUND

Glioblastoma is the most common and fatal primary malignant tumor in the central nervous system, and the prognosis is poor. Currently, there are no effective treatments for glioblastoma. Cordycepin is a natural active substance with significant anticancer activity and doxorubicin is a broad-spectrum anticancer drug. Cordycepin administered with doxorubicin is a potential drug combination for the treatment of glioblastoma. However, the mechanism of action for this drug combination has not yet been elucidated.

AIM OF THE STUDY

To explore the complex mechanism of cordycepin combined with doxorubicin against glioblastoma using network pharmacology and biological verification.

MATERIALS AND METHODS

We used an MTT assay, colony formation assay, and scratch healing to detect the growth, proliferation, and migration of LN-229, U251 and T98G cells. Putative targets and the potential mechanism of action for the drug combination in glioblastoma were obtained through online databases, network construction, and enrichment analyses. We verified the expression of EMT-related genes and identified important therapeutic targets by western blot.

RESULTS

In this study, the combination of doxorubicin and cordycepin was found to significantly inhibit cell proliferation and migration and can induce apoptosis. These effects are better together than with either drug alone. The drug combination inhibited EMT by upregulating the expression of E-cadherin protein and downregulating the expression of N-cadherin, ZEB1, and Twist1 proteins. There were 71 potential targets for the drug combination in glioblastoma, and Kyoto Encyclopedia of Genes and Genome analysis suggested that the anticancer process may be mediated by proteoglycans in cancer, the tumor necrosis factor signaling pathway, microRNA in cancer, pathways in cancer, and other pathways. To study the molecular mechanism of anticancer activity, we detected the expression of target proteins with downregulated expression of NFKB1, MAPK8, MYC, and MMP-9 proteins and upregulated expression of cleaved caspase 3 that promoted the apoptosis of LN-229 cells.

CONCLUSIONS

This study shows that the drug combination of doxorubicin and cordycepin effectively inhibits the growth and proliferation of LN-229 cells through multiple targets and multiple pathways, and the combination inhibits cell invasion and migration by regulating the EMT switch of tumor cells. Our findings provide new ideas about, and a theoretical basis for, the treatment of glioblastoma.

A Systematic Review of the Biological Effects of Cordycepin

We conducted a systematic review of the literature on the effects of cordycepin on cell survival and proliferation, inflammation, signal transduction and animal models. A total of 1204 publications on cordycepin were found by the cut-off date of 1 February 2021. After application of the exclusion criteria, 791 papers remained. These were read and data on the chosen subjects were extracted. We found 192 papers on the effects of cordycepin on cell survival and proliferation and calculated a median inhibitory concentration (IC50) of 135 µM. Cordycepin consistently repressed cell migration (26 papers) and cellular inflammation (53 papers). Evaluation of 76 papers on signal transduction indicated consistently reduced PI3K/mTOR/AKT and ERK signalling and activation of AMPK. In contrast, the effects of cordycepin on the p38 and Jun kinases were variable, as were the effects on cell cycle arrest (53 papers), suggesting these are cell-specific responses. The examination of 150 animal studies indicated that purified cordycepin has many potential therapeutic effects, including the reduction of tumour growth (37 papers), repression of pain and inflammation (9 papers), protecting brain function (11 papers), improvement of respiratory and cardiac conditions (8 and 19 papers) and amelioration of metabolic disorders (8 papers). Nearly all these data are consistent with cordycepin mediating its therapeutic effects through activating AMPK, inhibiting PI3K/mTOR/AKT and repressing the inflammatory response. We conclude that cordycepin has excellent potential as a lead for drug development, especially for age-related diseases. In addition, we discuss the remaining issues around the mechanism of action, toxicity and biodistribution of cordycepin.

Neuroprotective effects of salidroside on ageing hippocampal neurons and naturally ageing mice via the PI3K/Akt/TERT pathway

Studies have found that salidroside, isolated from Rhodiola rosea L, has various pharmacological activities, but there have been no studies on the effects of salidroside on brain hippocampal senescence. The purpose of this study was to investigate the mechanistic role of salidroside in hippocampal neuron senescence and injury. In this study, long-term cultured primary rat hippocampal neurons and naturally aged C57 mice were treated with salidroside. The results showed that salidroside increased the viability and MAP2 expression, reduced β-galactosidase (β-gal) levels of rat primary hippocampal neurons. Salidroside also improved cognition dysfunction in ageing mice and alleviated neuronal degeneration in the ageing mice CA1 region. Moreover, salidroside decreased the levels of oxidative stress and p21, p16 protein expressions of hippocampal neurons and ageing mice. Salidroside promoted telomerase reverse transcriptase (TERT) protein expression via the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway. In conclusion, our findings suggest that salidroside has the potential to be used as a therapeutic strategy for anti-ageing and ageing-related disease treatment.

Cordycepin induces apoptosis in human bladder cancer T24 cells through ROS-dependent inhibition of the PI3K/Akt signaling pathway

Cordycepin, a derivative of nucleoside adenosine, is one of the active ingredients extracted from the fungi of genus Cordyceps, which have been used for traditional herbal remedies. In this study, we examined the effect of cordycepin on the proliferation and apoptosis of human bladder cancer T24 cells and its mechanism of action. Cordycepin treatment significantly reduced the cell survival rate of T24 cells in a concentration-dependent manner, which was associated with the induction of apoptosis. Cordycepin activated caspase-8 and -9, which are involved in the initiation of extrinsic and intrinsic apoptosis pathways, respectively, and also increased caspase-3 activity, a typical effect caspase, subsequently leading to poly (ADP-ribose) polymerase cleavage. Additionally, cordycepin increased the Bax/Bcl-2 ratio and truncation of Bid, and destroyed the integrity of mitochondria, which contributed to the cytosolic release of cytochrome c. Moreover, cordycepin effectively inactivated the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, while LY294002, a PI3K/Akt inhibitor, increased the apoptosis-inducing effect of cordycepin. Cordycepin further enhanced the intracellular levels of reactive oxygen species (ROS), while the addition of N-acetyl cysteine (NAC), a ROS inhibitor, significantly diminished cordycepin-induced mitochondrial dysfunction and growth inhibition, and also blocked the inactivation of PI3K/Akt signaling pathway. Furthermore, the presence of NAC significantly attenuated the enhanced apoptotic cell death and reduction of cell viability by treatment with cordycepin and LY294002. Collectively, the data indicate that cordycepin induces apoptosis through the activation of extrinsic and intrinsic apoptosis pathways and the ROS-dependent inactivation of PI3K/Akt signaling in human bladder cancer T24 cells.

Therapeutic Potential and Biological Applications of Cordycepin and Metabolic Mechanisms in Cordycepin-Producing Fungi

Cordycepin (3′-deoxyadenosine), a cytotoxic nucleoside analogue found in Cordyceps militaris, has attracted much attention due to its therapeutic potential and biological value. Cordycepin interacts with multiple medicinal targets associated with cancer, tumor, inflammation, oxidant, polyadenylation of mRNA, etc. The investigation of the medicinal drug actions supports the discovery of novel targets and the development of new drugs to enhance the therapeutic potency and reduce toxicity. Cordycepin may be of great value owing to its medicinal potential as an external drug, such as in cosmeceutical, traumatic, antalgic and muscle strain applications. In addition, the biological application of cordycepin, for example, as a ligand, has been used to uncover molecular structures. Notably, studies that investigated the metabolic mechanisms of cordycepin-producing fungi have yielded significant information related to the biosynthesis of high levels of cordycepin. Here, we summarized the medicinal targets, biological applications, cytotoxicity, delivery carriers, stability, and pros/cons of cordycepin in clinical applications, as well as described the metabolic mechanisms of cordycepin in cordycepin-producing fungi. We posit that new approaches, including single-cell analysis, have the potential to enhance medicinal potency and unravel all facets of metabolic mechanisms of cordycepin in Cordyceps militaris.

RBFOX3 Promotes Tumor Growth and Progression via hTERT Signaling and Predicts a Poor Prognosis in Hepatocellular Carcinoma

Activation of the telomere maintenance mechanism is a key hallmark of cancer. Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, which is highly expressed in more than 80% of tumors, including hepatocellular carcinoma (HCC). However, the exact mechanisms by which hTERT is up-regulated in HCCs and promotes tumor growth and progression is not fully understood. The aim of this study was to discover the novel molecular targets that modulate hTERT signaling and HCC growth. In this study, we pulled down and identified RBFOX3 (RNA binding protein fox-1 homolog 3) as a novel hTERT promoter-binding protein in HCC cells using biotin-streptavidin-agarose pull-down and proteomics approach, and validated it as a regulatory factor for hTERT signaling and tumor growth in HCCs. Knockdown of RBFOX3 suppressed the promoter activity and expression of hTERT and consequently inhibited the growth and progression of HCC cells in vitro and in vivo. The suppression of HCC growth mediated by RBFOX3 knockdown could be rescued by hTERT overexpression. Conversely, exogenous overexpression of RBFOX3 activated the promoter activity and expression of hTERT and promoted the growth and progression of HCC cells. Moreover, we found that RBFOX3 interacted with AP-2β to regulate the expression of hTERT. Furthermore, we demonstrated that RBFOX3 expression was higher in the tumor tissues of HCC patients compared to the corresponding paracancer tissues, and was positively correlated with hTERT expression. Kaplan-Meier analysis showed that the HCC patients with high levels of RBFOX3 and hTERT had poor prognosis. Collectively, our data indicate that RBFOX3 promotes HCC growth and progression and predicts a poor prognosis by activating the hTERT signaling, and suggest that the RBFOX3/hTERT pathway may be a potential therapeutic target for HCC patients.

Fucoidan Induces ROS-Dependent Apoptosis in 5637 Human Bladder Cancer Cells by Downregulating Telomerase Activity via Inactivation of the PI3K/Akt Signaling Pathway

Preclinical Research Fucoidan, a sulfated polysaccharide, is a compound found in various species of seaweed that has anti-viral, anti-bacterial, anti-oxidant, anti-inflammatory, and immunomodulatory activities; however, the underlying relationship between apoptosis and anti-telomerase activity has not been investigated. Here, we report that fucoidan-induced apoptosis in 5637 human bladder cancer cells was associated with an increase in the Bax/Bcl-2 ratio, the dissipation of the mitochondrial membrane potential (MMP, Δψm), and cytosolic release of cytochrome c from the mitochondria. Under the same experimental conditions, fucoidan-treatment decreased hTERT (human telomerase reverse transcriptase) expression and the transcription factors, c-myc and Sp1. This was accompanied by decreased telomerase activity. Fucoidan-treatment also suppressed activation of the PI3K/Akt signaling pathway. Inhibition of PI3K/Akt signaling enhanced fucoidan-induced apoptosis and anti-telomerase activity. Meanwhile, fucoidan treatment increased the generation of intracellular ROS, whereas the over-elimination of ROS by N-acetylcysteine, an anti-oxidant, attenuated fucoidan-induced apoptosis, inhibition of hTERT, c-myc, and Sp1 expression, and reversed fucoidan-induced inactivation of the PI3K/Akt signaling pathway. Collectively, these data indicate that the induction of apoptosis and the inhibition of telomerase activity by fucoidan are mediated via ROS-dependent inactivation of the PI3K/Akt pathway. Drug Dev Res 78 : 37-48, 2017.   © 2016 Wiley Periodicals, Inc.

Transcription Regulation of the Human Telomerase Reverse Transcriptase (hTERT) Gene

Embryonic stem cells and induced pluripotent stem cells have the ability to maintain their telomere length via expression of an enzymatic complex called telomerase. Similarly, more than 85%–90% of cancer cells are found to upregulate the expression of telomerase, conferring them with the potential to proliferate indefinitely. Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase holoenzyme, is the rate-limiting factor in reconstituting telomerase activity in vivo. To date, the expression and function of the human Telomerase Reverse Transcriptase (hTERT) gene are known to be regulated at various molecular levels (including genetic, mRNA, protein and subcellular localization) by a number of diverse factors. Among these means of regulation, transcription modulation is the most important, as evident in its tight regulation in cancer cell survival as well as pluripotent stem cell maintenance and differentiation. Here, we discuss how hTERT gene transcription is regulated, mainly focusing on the contribution of trans-acting factors such as transcription factors and epigenetic modifiers, as well as genetic alterations in hTERT proximal promoter.