Ginsenoside Rg1 Inhibits Cell Proliferation and Induces Markers of Cell Senescence in CD34+CD38- Leukemia Stem Cells Derived from KG1α Acute Myeloid Leukemia Cells by Activating the Sirtuin 1 (SIRT1)/Tuberous Sclerosis Complex 2 (TSC2) Signaling Pathway

The Role of SIRT1 in Leukemia

OPINION STATEMENT

Leukemia is a type of hematological malignancy (HM) caused by uncontrolled proliferation, apoptosis, and differentiation of hematopoietic stem cells (HSCs). Leukemia cells proliferate greatly in the bone marrow (BM), infiltrate other tissues and organs, and affect the normal hematopoietic function. Although the emergence of new targeted agents and immune agents has improved the prognosis of patients, due to the complex pathogenic factors and heterogeneity of leukemia, there are still some patients with poor prognosis. Recent studies have shown that silent information regulator 1 (SIRT1) is involved in the proliferation, apoptosis, metabolism, and senescence of leukemia cells. As a double-edged sword in leukemia cells, SIRT1 can both promote and inhibit the growth of leukemia cells. Since its mechanism of action has not been elucidated, it is urgent to explore the regulatory mechanism of SIRT1 in leukemia. In this review, we discussed the mechanisms of SIRT1 in different aspects of leukemia, providing a theoretical basis for the treatment of patients with leukemia.

Anti-leukemia effects of ginsenoside monomer: A narrative review of pharmacodynamics study

Background

Leukemia is a prevalent disease with high mortality and morbidity rates. Current therapeutic approaches are expensive and have side effects.

Objective

In this investigation, we reviewed studies that investigated the anticancer effects of ginsenoside derivatives against leukemia and also explained the three main Ginsenoside derivatives (ginsenoside Rg3, Rh2, and Rg1) separately.

Methods

An extensive search was conducted in Pubmed, Web of Science, and Google Scholar and relevant studies that investigated anticancer effects of ginsenoside derivatives against leukemia cancer were extracted and reviewed.

Results

Preclinical studies reported that ginsenoside derivatives can induce apoptosis, suppress the proliferation of cancer cells, and induce differentiation and cell cycle arrest in leukemia cells. in addition, it can suppress the chemokine activity and extramedullary infiltration of leukemia cells from bone marrow. using herbal medicine and its derivatives is a promising approach to current health problems.

Conclusion

This review shows that ginsenoside derivatives can potentially suppress the growth of leukemia cells via various pathways and can be applied as a new natural medicine for future clinical research.

Using CADD tools to inhibit the overexpressed genes FAP, FN1, and MMP1 by repurposing ginsenoside C and Rg1 as a treatment for oral cancer

Oral cancer is one of the most common cancer types. Many factors can express certain genes that cause the proliferation of oral tissues. Overexpressed genes were detected in oral cancer patients; three were highly impacted. FAP, FN1, and MMP1 were the targeted genes that showed inhibition results in silico by ginsenoside C and Rg1. Approved drugs were retrieved from the DrugBank database. The docking scores show an excellent interaction between the ligands and the targeted macromolecules. Further molecular dynamics simulations showed the binding stability of the proposed natural products. This work recommends repurposing ginsenoside C and Rg1 as potential binders for the selected targets and endorses future experimental validation for the treatment of oral cancer.

Role of SIRT1 in Chemoresistant Leukemia

Leukemias of the AML, CML, and CLL types are the most common blood cancers worldwide, making them a major global public health problem. Furthermore, less than 24% of patients treated with conventional chemotherapy (low-risk patients) and 10-15% of patients ineligible for conventional chemotherapy (high-risk patients) survive five years. The low levels of survival are mainly due to toxicity and resistance to chemotherapy or other medication, the latter leading to relapse of the disease, which is the main obstacle to the treatment of leukemia. Drug resistance may include different molecular mechanisms, among which epigenetic regulators are involved. Silent information regulator 2 homolog 1 (SIRT1) is an epigenetic factor belonging to the sirtuin (SIRT) family known to regulate aspects of chromatin biology, genome stability, and metabolism, both in homeostasis processes and in different diseases, including cancer. The regulatory functions of SIRT1 in different biological processes and molecular pathways are dependent on the type and stage of the neoplasia; thus, it may act as both an oncogenic and tumor suppressor factor and may also participate in drug resistance. In this review, we explore the role of SIRT1 in drug-resistant leukemia and its potential as a therapeutic target.

Ginsenosides on stem cells fate specification-a novel perspective

Recent studies have demonstrated that stem cells have attracted much attention due to their special abilities of proliferation, differentiation and self-renewal, and are of great significance in regenerative medicine and anti-aging research. Hence, finding natural medicines that intervene the fate specification of stem cells has become a priority. Ginsenosides, the key components of natural botanical ginseng, have been extensively studied for versatile effects, such as regulating stem cells function and resisting aging. This review aims to summarize recent progression regarding the impact of ginsenosides on the behavior of adult stem cells, particularly from the perspective of proliferation, differentiation and self-renewal.

RUNX3 mediates keloid fibroblast proliferation through deacetylation of EZH2 by SIRT1

BACKGROUND

Keloid is a benign proliferative fibrous disease featured by excessive fibroblast proliferation after skin injury. However, the mechanism of abnormal cell proliferation is still unclear. Herein, we investigated the mechanism of abnormal proliferation in keloids involving Sirtuin 1(SIRT1)/ Zeste Homolog 2 (EZH2)/ Runt-related transcription factor 3 (RUNX3).  METHODS: HE staining was used to observe the histopathological changes. Western blot was performed to detect SIRT1/EZH2/RUNX3 and cell cycle related proteins. RT-PCR detected EZH2 mRNA. After knockdown of EZH2 or overexpression of RUNX3, cell proliferation and cell cycle was analyzed. Immunoprecipitation was used to detect acetylated EZH2.

RESULTS

The results showed that overexpression of RUNX3 inhibited cell proliferation and arrested cell cycle at G1/S phase, whereas inhibition of SIRT1 promoted cell proliferation and G1/S phase of the cell cycle. Knockdown of EZH2 promoted the expression of RUNX3, inhibited cell proliferation and shortened the progression of G1 to S phase. Simultaneous knockdown of EZH2 and inhibition of SIRT1 reversed these effects. Inhibition of SIRT1 increased its protein stability by increasing EZH2 acetylation, thereby reducing the expression of RUNX3 and promoting cell proliferation.

CONCLUSIONS

Conclusively, the SIRT1/EZH2/RUNX3 axis may be an important pathway in the regulation of abnormal proliferation in keloids.

The role of protein acetylation in carcinogenesis and targeted drug discovery

Protein acetylation is a reversible post-translational modification, and is involved in many biological processes in cells, such as transcriptional regulation, DNA damage repair, and energy metabolism, which is an important molecular event and is associated with a wide range of diseases such as cancers. Protein acetylation is dynamically regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs) in homeostasis. The abnormal acetylation level might lead to the occurrence and deterioration of a cancer, and is closely related to various pathophysiological characteristics of a cancer, such as malignant phenotypes, and promotes cancer cells to adapt to tumor microenvironment. Therapeutic modalities targeting protein acetylation are a potential therapeutic strategy. This article discussed the roles of protein acetylation in tumor pathology and therapeutic drugs targeting protein acetylation, which offers the contributions of protein acetylation in clarification of carcinogenesis, and discovery of therapeutic drugs for cancers, and lays the foundation for precision medicine in oncology.

Phytochemicals as new therapeutic candidates simultaneously stimulate proliferation and counteract senescence of stem cells

Mesenchymal stem cells (MSCs) are promising candidates for regenerative therapy. However, the research and clinical application of MSCs are greatly hindered by the limited cells proliferation and replicative senescence. Therapeutic agents that can both enhance the proliferative ability and decrease the replicative senescence of MSCs are greatly needed, however, not been reported yet. Herein, for the first time, we identified 11 natural compounds from medicinal plants with both excellent proliferative and anti-senescence abilities in MSCs. The qPCR analysis indicated underlying mechanisms associated with fibroblast growth factor, transforming growth factor, Wnt/β-catenin and leukemia-induced factor in proliferation; the reactive oxygen species production, mitochondrial dysfunction autophagy and proteostasis are involved in cells senescence-related mechanism. Phytochemicals are demonstrated as novel therapeutic candidates with promising effects in both stimulating proliferation and retarding replicative senescence of stem cells with high safety.

Targeting cellular senescence in cancer by plant secondary metabolites: A systematic review

Senescence suppresses tumor growth, while also developing a tumorigenic state in the nearby cells that is mediated by senescence-associated secretory phenotypes (SASPs). The dual function of cellular senescence stresses the need for identifying multi-targeted agents directed towards the promotion of cell senescence in cancer cells and suppression of the secretion of pro-tumorigenic signaling mediators in neighboring cells. Natural secondary metabolites have shown favorable anticancer responses in recent decades, as some have been found to target the senescence-associated mediators and pathways. Furthermore, phenolic compounds and polyphenols, terpenes and terpenoids, alkaloids, and sulfur-containing compounds have shown to be promising anticancer agents through the regulation of paracrine and autocrine pathways. Plant secondary metabolites are potential regulators of SASPs factors that suppress tumor growth through paracrine mediators, including growth factors, cytokines, extracellular matrix components/enzymes, and proteases. On the other hand, ataxia-telangiectasia mutated, ataxia-telangiectasia and Rad3-related, extracellular signal-regulated kinase/mitogen-activated protein kinase, phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin, nuclear factor-κB, Janus kinase/signal transducer and activator of transcription, and receptor tyrosine kinase-associated mediators are main targets of candidate phytochemicals in the autocrine senescence pathway. Such a regulatory role of phytochemicals on senescence-associated pathways are associated with cell cycle arrest and the attenuation of apoptotic/inflammatory/oxidative stress pathways. The current systematic review highlights the critical roles of natural secondary metabolites in the attenuation of autocrine and paracrine cellular senescence pathways, while also elucidating the chemopreventive and chemotherapeutic capabilities of these compounds. Additionally, we discuss current challenges, limitations, and future research indications.

A SIRT1 Activator, Ginsenoside Rc, Promotes Energy Metabolism in Cardiomyocytes and Neurons

Targeting SIRT1 signaling pathway could improve glucose aerobic metabolism and mitochondrial biosynthesis to resist cardiac and neurological injuries. Ginsenoside Rc has been identified for targeting mitochondrial function, but how ginsenoside Rc interacts with SIRT1 to regulate energy metabolism in cardiomyocytes and neurons under physiological or ischemia/reperfusion (I/R)-injured conditions has not been clearly investigated. Here, we confirm the interaction of Rc on the residue sites of SIRT1 in promoting its activity. Ginsenoside Rc significantly promotes mitochondrial biogenesis and increases the levels of electron-transport chain complex II-IV in cardiomyocytes and neurons. Meanwhile, ginsenoside Rc pretreatment increases ATP production, glucose uptake, and the levels of hexokinase I/II and mitochondrial pyruvate carrier I/II in both cell models. In addition, ginsenoside Rc activates the PGC1α pathway to induce mitochondrial biosynthesis. More importantly, ginsenoside Rc reduces mitochondrial damage and apoptosis through SIRT1 restoration-mediated reduction of PGC1α acetylation in the I/R-induced cardiac and neuronal models. Collectively, the in vitro and in vivo data indicate that ginsenoside Rc as a SIRT1 activator promotes energy metabolism to improve cardio- and neuroprotective functions under normal and I/R injury conditions, which provides new insights into the molecular mechanism of ginsenoside Rc as a protective agent.

Nicotinamide as a Foundation for Treating Neurodegenerative Disease and Metabolic Disorders

Neurodegenerative disorders impact more than one billion individuals worldwide and are intimately tied to metabolic disease that can affect another nine hundred individuals throughout the globe. Nicotinamide is a critical agent that may offer fruitful prospects for neurodegenerative diseases and metabolic disorders, such as diabetes mellitus. Nicotinamide protects against multiple toxic environments that include reactive oxygen species exposure, anoxia, excitotoxicity, ethanolinduced neuronal injury, amyloid (Aß) toxicity, age-related vascular disease, mitochondrial dysfunction, insulin resistance, excess lactate production, and loss of glucose homeostasis with pancreatic β-cell dysfunction. However, nicotinamide offers cellular protection in a specific concentration range, with dosing outside of this range leading to detrimental effects. The underlying biological pathways of nicotinamide that involve the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), and mammalian forkhead transcription factors (FoxOs) may offer insight for the clinical translation of nicotinamide into a safe and efficacious therapy through the modulation of oxidative stress, apoptosis, and autophagy. Nicotinamide is a highly promising target for the development of innovative strategies for neurodegenerative disorders and metabolic disease, but the benefits of this foundation depend greatly on gaining a further understanding of nicotinamide's complex biology.

Targeting the core of neurodegeneration: FoxO, mTOR, and SIRT1

The global increase in lifespan noted not only in developed nations, but also in large developing countries parallels an observed increase in a significant number of non-communicable diseases, most notable neurodegenerative disorders. Neurodegenerative disorders present a number of challenges for treatment options that do not resolve disease progression. Furthermore, it is believed by the year 2030, the services required to treat cognitive disorders in the United States alone will exceed $2 trillion annually. Mammalian forkhead transcription factors, silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae), the mechanistic target of rapamycin, and the pathways of autophagy and apoptosis offer exciting avenues to address these challenges by focusing upon core cellular mechanisms that may significantly impact nervous system disease. These pathways are intimately linked such as through cell signaling pathways involving protein kinase B and can foster, sometimes in conjunction with trophic factors, enhanced neuronal survival, reduction in toxic intracellular accumulations, and mitochondrial stability. Feedback mechanisms among these pathways also exist that can oversee reparative processes in the nervous system. However, mammalian forkhead transcription factors, silent mating type information regulation 2 homolog 1, mechanistic target of rapamycin, and autophagy can lead to cellular demise under some scenarios that may be dependent upon the precise cellular environment, warranting future studies to effectively translate these core pathways into successful clinical treatment strategies for neurodegenerative disorders.

Metabolic syndrome increases senescence-associated micro-RNAs in extracellular vesicles derived from swine and human mesenchymal stem/stromal cells

BACKGROUND

The metabolic syndrome (MetS) is a combination of cardiovascular risk-factors, including obesity, hypertension, hyperglycemia, and insulin resistance. MetS may induce senescence in mesenchymal stem/stromal cells (MSC) and impact their micro-RNA (miRNA) content. We hypothesized that MetS also alters senescence-associated (SA) miRNAs in MSC-derived extracellular vesicles (EVs), and interferes with their function.

METHODS

EVs were collected from abdominal adipose tissue-derived MSCs from pigs with diet-induced MetS or Lean controls (n = 6 each), and from patients with MetS (n = 4) or age-matched Lean controls (n = 5). MiRNA sequencing was performed to identify dysregulated miRNAs in these EVs, and gene ontology to analyze their SA-genes targeted by dysregulated miRNAs. To test for EV function, MetS and Lean pig-EVs were co-incubated with renal tubular cells in-vitro or injected into pigs with renovascular disease (RVD, n = 6 each) in-vivo. SA-b-Galactosidase and trichrome staining evaluated cellular senescence and fibrosis, respectively.

RESULTS

Both humans and pigs with MetS showed obesity, hypertension, and hyperglycemia/insulin resistance. In MetS pigs, several upregulated and downregulated miRNAs targeted 5768 genes in MSC-EVs, 68 of which were SA. In MetS patients, downregulated and upregulated miRNAs targeted 131 SA-genes, 57 of which overlapped with pig-EVs miRNA targets. In-vitro, MetS-MSC-EVs induced greater senescence in renal tubular cells than Lean-MSC-EVs. In-vivo, Lean-MSC-EVs attenuated renal senescence, fibrosis, and dysfunction more effectively than MetS-MSC-EVs.

CONCLUSIONS

MetS upregulates SA-miRNAs in swine MSC-EVs, which is conserved in human subjects, and attenuates their ability to blunt cellular senescence and repair injured target organs. These alterations need to be considered when designing therapeutic regenerative approaches. Video abstract.

Nicotinamide: Oversight of Metabolic Dysfunction Through SIRT1, mTOR, and Clock Genes

Metabolic disorders that include diabetes mellitus present significant challenges for maintaining the welfare of the global population. Metabolic diseases impact all systems of the body and despite current therapies that offer some protection through tight serum glucose control, ultimately such treatments cannot block the progression of disability and death realized with metabolic disorders. As a result, novel therapeutic avenues are critical for further development to address these concerns. An innovative strategy involves the vitamin nicotinamide and the pathways associated with the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), the mechanistic target of rapamycin (mTOR), mTOR Complex 1 (mTORC1), mTOR Complex 2 (mTORC2), AMP activated protein kinase (AMPK), and clock genes. Nicotinamide maintains an intimate relationship with these pathways to oversee metabolic disease and improve glucose utilization, limit mitochondrial dysfunction, block oxidative stress, potentially function as antiviral therapy, and foster cellular survival through mechanisms involving autophagy. However, the pathways of nicotinamide, SIRT1, mTOR, AMPK, and clock genes are complex and involve feedback pathways as well as trophic factors such as erythropoietin that require a careful balance to ensure metabolic homeostasis. Future work is warranted to gain additional insight into these vital pathways that can oversee both normal metabolic physiology and metabolic disease.