S-Adenosylmethionine Affects ERK1/2 and Stat3 Pathways and Induces Apotosis in Osteosarcoma Cells

S-adenosylmethionine improves cognitive impairment in D-galactose-induced brain aging by inhibiting oxidative stress and neuroinflammation

Oxidative stress and neuroinflammation play crucial roles in aging. S-adenosylmethionine (SAM), a popular supplement, is a potential antioxidant and candidate therapy for depression. This study aimed to evaluate the neuroprotective effects of SAM on D-galactose-induced brain aging and explore its underlying mechanisms. Brain aging model was established with D-galactose (180 mg/kg/day) for 8 weeks. During the last 4 weeks, SAM (16 mg/kg) was co-administrated with D-galactose. Behavior tests were used to assess cognitive function and depression-like behaviors of rats. Results showed that cognitive impairment and depression-like behaviors were reversed by SAM. SAM reduced neuronal cell loss, increased brain-derived neurotrophic factor level in the hippocampus, inhibited amyloid-β level and microglia activation, as well as pro-inflammatory factors levels in the hippocampus and serum. Further, SAM enhanced antioxidant capacity and attenuated cholinergic damage by reducing malondialdehyde levels, increasing acetylcholine levels, expression levels of α7 nicotinic acetylcholine receptor (α7nAChR), nuclear factor erythrocyte 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) in the hippocampus. Above all, SAM has a potential neuroprotective effect on ameliorating cognitive impairment in brain aging, which is related to inhibition of oxidative stress and neuroinflammation, as well as α7nAChR signals. DATA AVAILABILITY: Data will be made available on request.

Co-Targeting Luminal B Breast Cancer with S-Adenosylmethionine and Immune Checkpoint Inhibitor Reduces Primary Tumor Growth and Progression, and Metastasis to Lungs and Bone

Breast cancer (BCa) is the most prevalent cancer in females and has a high rate of mortality, especially due to increased metastasis to skeletal and non-skeletal sites. Despite the marked clinical accomplishment of immune checkpoint inhibitor (CPI) therapy in patients with several cancers, it has had limited success in luminal subtypes of BCa. Accordingly, recent efforts have focused on combination therapy with CPI, including epigenetic modulators, to increase response rates of CPI in luminal BCa. We have previously shown that S-adenosylmethionine (SAM), the ubiquitous methyl donor, has strong anti-cancer effects in various cancers, including all subtypes of BCa. In the current study, we took a novel approach and examined the effect of CPI alone and in combination with SAM on tumor growth and metastasis in a syngeneic mouse model of luminal B BCa. We showed that SAM decreases cell proliferation, colony-formation (survival), and invasion of luminal B BCa cell lines (Eo771, R221A) in vitro. In in vivo studies, in Eo771 tumor-bearing mice, either SAM or anti-PD-1 antibody treatment alone significantly reduced tumor growth and progression, while the SAM+anti-PD-1 combination treatment had the highest anti-cancer efficacy of all groups. The SAM+anti-PD-1 combination reduced the percentage of animals with lung metastasis, as well as total metastatic lesion area, compared to control. Additionally, the SAM+anti-PD-1 combination significantly reduced the skeletal lesion area and protected tibial integrity to a greater extent than the monotherapies in an Eo771 bone metastasis model. Transcriptome analysis of Eo771 primary tumors revealed significant downregulation of pro-metastatic genes, including Matrix metalloproteinases (MMPs) and related pathways. On the other hand, CD8⁺ T cell infiltration, CD8⁺ T cell cytotoxicity (elevated granzymes), and immunostimulatory genes and pathways were significantly upregulated by the combination treatment. The results presented point to a combination of SAM with CPI as a possible treatment for luminal B BCa that should be tested in clinical studies.

S-Adenosylmethionine Inhibits Colorectal Cancer Cell Migration through Mirna-Mediated Targeting of Notch Signaling Pathway

Metastasis is a leading cause of mortality and poor prognosis in colorectal cancer (CRC). Thus, the identification of new compounds targeting cell migration represents a major clinical challenge. Recent findings evidenced a central role for dysregulated Notch in CRC and a correlation between Notch overexpression and tumor metastasis. MicroRNAs (miRNAs) have been reported to cross-talk with Notch for its regulation. Therefore, restoring underexpressed miRNAs targeting Notch could represent an encouraging therapeutic approach against CRC. In this context, S-adenosyl-L-methionine (AdoMet), the universal biological methyl donor, being able to modulate the expression of oncogenic miRNAs could act as a potential antimetastatic agent. Here, we showed that AdoMet upregulated the onco-suppressor miRNAs-34a/-34c/-449a and inhibited HCT-116 and Caco-2 CRC cell migration. This effect was associated with reduced expression of migration-/EMT-related protein markers. We also found that, in colorectal and triple-negative breast cancer cells, AdoMet inhibited the expression of Notch gene, which, by luciferase assay, resulted the direct target of miRNAs-34a/-34c/-449a. Gain- and loss-of-function experiments with miRNAs mimics and inhibitors demonstrated that AdoMet exerted its inhibitory effects by upregulating miRNAs-34a/-34c/-449a. Overall, these data highlighted AdoMet as a novel Notch inhibitor and suggested that the antimetastatic effects of AdoMet involve the miRNA-mediated targeting of Notch signaling pathway.

S-Adenosylmethionine affects ERK1/2 and STAT3 pathway in androgen-independent prostate cancer cells

Background

The most critical point in the treatment of prostate cancer is the progression towards a hormone-refractory tumour, making research on alternative therapies necessary. This study focused on the methyl donor S-adenosylmethionine (SAM), which is known to act as an antitumourigenic in several cancer cell lines. Though a genome-wide downregulation of proto-oncogenes in prostate cancer cell lines treated with SAM is obvious, the anticancer effects remain elusive. Thus, in this study, the impact of SAM treatment on the cell cycle, apoptosis and cancer-related pathways was investigated.

Methods and results

After performing SAM treatment on prostate cancer cell lines (PC-3 and DU145), a cell-cycle arrest during the S-phase, a downregulation of cyclin A protein levels and an upregulation of p21 cell cycle inhibitor were observed. The proapoptotic Bax/Bcl-2 ratio and the caspase-3 activity were elevated; additionally, the apoptosis rate of SAM treated cells increased significantly in a time-dependent manner. Moreover, immunoblots displayed a downregulation of Erk1/2 and STAT3 phosphorylation accompanied by a reduced expression of the STAT3 protein.

Conclusion

SAM caused changes in cancer-related pathways, probably leading to the effects on the cell cycle and apoptosis rate. These results provide deeper insights into the anticancer effects of SAM on prostate cancer cells.

SAMe, Choline, and Valproic Acid as Possible Epigenetic Drugs: Their Effects in Pregnancy with a Special Emphasis on Animal Studies

In this review, we discuss the functions and main effects on pregnancy outcomes of three agents that have the ability to induce epigenetic modifications: valproic acid (VPA), a well-known teratogen that is a histone deacetylase inhibitor; S-adenosylmethionine (SAMe), the most effective methyl donor; and choline, an important micronutrient involved in the one methyl group cycle and in the synthesis of SAMe. Our aim was to describe the possible effects of these compounds when administered during pregnancy on the developing embryo and fetus or, if administered postnatally, their effects on the developing child. These substances are able to modify gene expression and possibly alleviate neurobehavioral changes in disturbances that have epigenetic origins, such as autism spectrum disorder (ASD), depression, Rett syndrome, and fetal alcohol spectrum disorder (FASD). Valproic acid and SAMe are antagonistic epigenetic modulators whether administered in utero or postnatally. However, VPA is a major human teratogen and, whenever possible, should not be used by pregnant women. Most currently relevant data come from experimental animal studies that aimed to explore the possibility of using these substances as epigenetic modifiers and possible therapeutic agents. In experimental animals, each of these substances was able to alleviate the severity of several well-known diseases by inducing changes in the expression of affected genes or by other yet unknown mechanisms. We believe that additional studies are needed to further explore the possibility of using these substances, and similar compounds, for the treatment of "epigenetic human diseases".

The Crucial Roles of Intermediate Metabolites in Cancer

Metabolic alteration, one of the hallmarks of cancer cells, is important for cancer initiation and development. To support their rapid growth, cancer cells alter their metabolism so as to obtain the necessary energy and building blocks for biosynthetic pathways, as well as to adjust their redox balance. Once thought to be merely byproducts of metabolic pathways, intermediate metabolites are now known to mediate epigenetic modifications and protein post-transcriptional modifications (PTM), as well as connect cellular metabolism with signal transduction. Consequently, they can affect a myriad of processes, including proliferation, apoptosis, and immunity. In this review, we summarize multiple representative metabolites involved in glycolysis, the pentose phosphate pathway (PPP), the tricarboxylic acid (TCA) cycle, lipid synthesis, ketogenesis, methionine metabolism, glutamine metabolism, and tryptophan metabolism, focusing on their roles in chromatin and protein modifications and as signal-transducing messengers.

Mutual Correlation between Non-Coding RNA and S-Adenosylmethionine in Human Cancer: Roles and Therapeutic Opportunities

Simple Summary

Non-coding RNAs and S-adenosylmethionine, the methyl donor required in all epigenetic methylation reactions, have emerged in recent years as crucial players in the modulation of gene expression in different types of human cancers. This review summarizes the most recent findings on reciprocal regulation between AdoMet and non-coding RNAs. AdoMet was found to exert anticancer activity through epigenetic regulation of non-coding RNAs, including microRNAs, long non-coding RNAs and circular RNAs. On the other hand, several microRNAs and long non-coding RNAs have been reported to display regulatory effects on the expression of genes involved in AdoMet synthesis and metabolism. Increasing knowledge on the relationship between AdoMet and non-coding RNAs will provide insights for further development of diagnostic and therapeutic strategies for cancer treatments.

Abstract

Epigenetics includes modifications in DNA methylation, histone and chromatin structure, and expression of non-coding RNAs (ncRNAs), especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Knowledge of the relationships between S-adenosylmethionine (AdoMet or SAM), the universal methyl donor for all epigenetic methylation reactions and miRNAs or lncRNAs in human cancer may provide helpful insights for the development of new end more effective anticancer therapeutic approaches. In recent literature, a complex network of mutual interconnections between AdoMet and miRNAs or lncRNAs has been reported and discussed. Indeed, ncRNAs expression may be regulated by epigenetic mechanisms such as DNA and RNA methylation and histone modifications. On the other hand, miRNAs or lncRNAs may influence the epigenetic apparatus by modulating the expression of its enzymatic components at the post-transcriptional level. Understanding epigenetic mechanisms, such as dysregulation of miRNAs/lncRNAs and DNA methylation, has become of central importance in modern research. This review summarizes the recent findings on the mechanisms by which AdoMet and miRNA/lncRNA exert their bioactivity, providing new insights to develop innovative and more efficient anticancer strategies based on the interactions between these epigenetic modulators.

S-Adenosylmethionine Inhibits Cell Growth and Migration of Triple Negative Breast Cancer Cells through Upregulating MiRNA-34c and MiRNA-449a

Triple-negative breast cancer (TNBC) is one of the most common malignancies worldwide and shows maximum invasiveness and a high risk of metastasis. Recently, many natural compounds have been highlighted as a valuable source of new and less toxic drugs to enhance breast cancer therapy. Among them, S-adenosyl-L-methionine (AdoMet) has emerged as a promising anti-cancer agent. MicroRNA (miRNA or miR)-based gene therapy provides an interesting antitumor approach to integrated cancer therapy. In this study, we evaluated AdoMet-induced modulation of miRNA-34c and miRNA-449a expression in MDA-MB-231 and MDA-MB-468 TNBC cells. We demonstrated that AdoMet upregulates miR-34c and miR-449a expression in both cell lines. We found that the combination of AdoMet with miR-34c or miR-449a mimic strongly potentiated the pro-apoptotic effect of the sulfonium compound by a caspase-dependent mechanism. For the first time, by video time-lapse microscopy, we showed that AdoMet inhibited the in vitro migration of MDA-MB-231 and MDA-MB-468 cells and that the combination with miR-34c or miR-449a mimic strengthened the effect of the sulfonium compound through the modulation of β-catenin and Small Mother Against Decapentaplegic (SMAD) signaling pathways. Our results furnished the first evidence that AdoMet exerts its antitumor effects in TNBC cells through upregulating the expression of miR-34c and miR-449a.

Pharmacokinetic study of a novel oral formulation of S-adenosylmethionine (MSI-195) in healthy subjects: dose escalation, food effect and comparison to a commercial nutritional supplement product

Background

A novel, high bioavailability oral, enteric coated tablet formulation of S-adenosylmethionine (MSI-195) has been developed for life science application. The present research reports on a Phase 1 study to (i) determine the safety of single doses of MSI-195 (ii) to determine the dose proportionality of MSI-195 at doses of 400, 800 and 1600 mg (iii) determine the pharmacokinetics of MSI-195 compared with a commercial reference product (SAM-e Complete™) over 24 h and (iv) to determine the effect of food on the pharmacokinetic profile of MSI-195 in human subjects.

Methods

This study was a pharmacokinetic and safety evaluation of MSI-195 and a commercial comparator broken into two stages. The first stage was an exploratory single ascending dose design of MSI-195 in 8 healthy normal male volunteers. The second stage was a single dose evaluation, targeting 26 male and female volunteers at set doses of MSI-195 and commercial comparator in a cross-over design followed by a food effect study on MSI-195. Plasma samples were collected and assayed for S-adenosylmethionine using a validated HPLC method with MS/MS detection. The main absorption and disposition parameters were calculated using a non-compartmental approach with a log-linear terminal phase assumption. Statistical analysis was based on an ANOVA model or t test as appropriate.

Results

MSI-195 was found to be generally well tolerated with an adverse event profile similar to the SAM-e Complete™ comparator product. The relative bioavailability of MSI-195 was approximately 2.8-fold higher than SAM-e Complete based on area under the curve (AUC) ratios for the two products and the MSI-195 formulation exposure based on AUC was found to be approximately dose proportional. There was a significant food effect for MSI-195 with a delayed time to maximum absorption T_max, going from 4.5 h under fasted conditions to 13 h under fed conditions, and area under the curve with food reduced to 55% of that seen under fasting conditions.

Conclusions

The overall conclusion was that MSI-195 was well tolerated and has markedly higher bioavailability compared with both the SAM-e Complete™ commercial product tested and, on a per mg basis, products reported in other literature.

Trial registration

ClinicalTrials.gov, identifier NCT04623034. Retrospectively registered Nov 9, 2020.

Mi-RNA-888-5p Is Involved in S-Adenosylmethionine Antitumor Effects in Laryngeal Squamous Cancer Cells

Simple Summary

Laryngeal Squamous Cell Carcinoma (LSCC) is a leading cause of cancer-related death with a strong interest in identifying and developing new treatments. MicroRNAs (miRNAs) have emerged as one of the most important determinants of neoplastic transformation and progression. miRNA modulation causes significant antitumor effects both in vitro and in vivo and miRNA regulation by natural compounds, represents a promising approach in the field of cancer research. S-Adenosylmethionine (AdoMet), a natural compound and a nutritional supplement, is well known for its antiproliferative and pro-apoptotic effects in many kinds of human tumors. Here, we report that AdoMet induces ER-stress and autophagy paralleled by miR-888-5p downregulation and MYCBP and CDH1 increased expression in Laryngeal Squamous Cancer Cells (LSCC). This study contributes to understanding the mechanisms by which AdoMet exerts its effects in LSCC, suggesting the use of AdoMet as an attractive miRNA-mediated chemopreventive and therapeutic strategy against cancer.

Abstract

(1) Purpose: The methyl donor S-Adenosylmethionine (AdoMet) has been widely explored as a therapeutic compound, and its application-alone or in combination with other molecules-is emerging as a potential effective strategy for the treatment and chemoprevention of tumours. In this study, we investigated the antitumor activity of AdoMet in Laryngeal Squamous Cell Carcinoma (LSCC), exploring the underlying mechanisms. (2) Results: We demonstrated that AdoMet induced ROS generation and triggered autophagy with a consistent increase in LC3B-II autophagy-marker in JHU-SCC-011 and HNO210 LSCC cells. AdoMet induced ER-stress and activated UPR signaling through the upregulation of the spliced form of XBP1 and CHOP. To gain new insights into the molecular mechanisms underlying the antitumor activity of AdoMet, we evaluated the regulation of miRNA expression profile and we found a downregulation of miR-888-5p. We transfected LSCC cells with miR-888-5p inhibitor and exposed the cells to AdoMet for 48 and 72 h. The combination of AdoMet with miR-888-5p inhibitor synergistically induced both apoptosis and inhibited cell migration paralleled by the up-regulation of MYCBP and CDH1 genes and of their targets. (3) Conclusion: Overall, these data highlighted that epigenetic reprogramming of miRNAs by AdoMet play an important role in inhibiting apoptosis and migration in LSCC cell lines.

S-adenosylmethionine induces apoptosis and cycle arrest of gallbladder carcinoma cells by suppression of JAK2/STAT3 pathways

S-adenosylmethionine (SAM) is a naturally occurring physiologic molecule found ubiquitously in all mammalian cells and an essential compound in many metabolic pathways. It has been reported to possess many pharmacological properties including cancer-preventive and anticancer effects. However, the precise molecular mechanism involved in its anticancer effect is not yet clear. The present study is conducted to investigate the anticancer activity and the underlying mechanisms of SAM on human gallbladder cancer cells (GBC-SD and SGC-996) in vitro and in vivo. Cells were dealt with SAM and subjected to cell viability, colony formation, Hoechst staining, apoptosis, cycle arrest, western blot, and xenograft tumorigenicity assay. Experimental results showed that SAM could significantly inhibit the growth and proliferation and induce the apoptosis as well as cell cycle arrest in G0/G1 phase of GBC-SD and SGC-996 cells in a dose-dependent manner in vitro. The expression levels of p-JAK2, p-STAT3, Mcl-1, and Bcl-XL were significantly downregulated. In addition, inhibition of the JAK2/STAT3 pathway significantly enhanced the anti-apoptotic effect of SAM, suggesting the key roles of JAK2/STAT3 in the process. More importantly, our in vivo studies demonstrated that administration of SAM could significantly decrease the tumor weight and volume and immunohistochemistry analysis proved the downregulation of p-JAK2 and p-STAT3 in tumor tissues following SAM treatment, consistent with our in vitro results. In summary, our findings indicated that SAM can inhibit cell proliferation and induce apoptosis as well as cycle arrest of GBC cells by suppression of JAK2/STAT3 pathways and the dramatic effects of SAM hinting that SAM might be a useful therapeutic option for patients suffering from gallbladder cancer.

Therapeutic Potential of the Natural Compound S-Adenosylmethionine as a Chemoprotective Synergistic Agent in Breast, and Head and Neck Cancer Treatment: Current Status of Research

The present review summarizes the most recent studies focusing on the synergistic antitumor effect of the physiological methyl donor S-adenosylmethionine (AdoMet) in association with the main drugs used against breast cancer and head and neck squamous cell carcinoma (HNSCC), two highly aggressive and metastatic malignancies. In these two tumors the chemotherapy approach is recommended as the first choice despite the numerous side effects and recurrence of metastasis, so better tolerated treatments are needed to overcome this problem. In this regard, combination therapy with natural compounds, such as AdoMet, a molecule with pleiotropic effects on multiple cellular processes, is emerging as a suitable strategy to achieve synergistic anticancer efficacy. In this context, the analysis of studies conducted in the literature highlighted AdoMet as one of the most effective and promising chemosensitizing agents to be taken into consideration for inclusion in emerging antitumor therapeutic modalities such as nanotechnologies.

Effects of S‑adenosyl‑L‑methionine on the invasion and migration of head and neck squamous cancer cells and analysis of the underlying mechanisms

S-Adenosyl-L-methionine (AdoMet) is the principal methyl donor in transmethylation reactions fundamental to sustaining epigenetic modifications. Over the past decade, AdoMet has been extensively investigated for its anti- proliferative, pro-apoptotic and anti-metastatic roles in several types of human cancer. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer worldwide, and is an aggressive type of cancer that is associated with a high recurrence rate, metastasis and poor treatment outcomes. The present study demonstrates, for the first time, to the best of our knowledge, that AdoMet induces cell cycle arrest and inhibits the migratory and invasive ability of two different HNSCC cell lines, oral Cal-33 and laryngeal JHU-SCC-011 cells. In both cell lines, AdoMet attenuated cell cycle progression, decreased the protein level of several cyclins and downregulated the expression of p21 cell cycle inhibitor. Moreover, AdoMet was able to inhibit Cal-33 and JHU-SCC-011 cell migration in a dose-dependent manner after 24 and 48 h, respectively, and also induced a significant reduction in the cell invasive ability, as demonstrated by Matrigel invasion assay monitored by the xCELLigence RTCA system. Western blot analysis of several migration and invasion markers confirmed the inhibitory effects exerted by AdoMet on these processes and highlighted AKT, β-catenin and small mothers against decapentaplegic (SMAD) as the main signaling pathways modulated by AdoMet. The present study also demonstrated that the combination of AdoMet and cisplatin synergistically inhibited HNSCC cell migration. Taken together, these findings demonstrate that the physiological compound, AdoMet, affects the motility and extracellular matrix invasive capability in HNSCC. Thus, AdoMet may prove to be a good candidate for future drug development against metastatic cancer.

AdipoRon Affects Cell Cycle Progression and Inhibits Proliferation in Human Osteosarcoma Cells

AdipoRon (AdipoR) is the first synthetic molecule acting as a selective and potent adiponectin receptor agonist. Recently, the possible pharmacological use of AdipoR in different pathological conditions has been addressed. Interestingly, initial evidence suggests that AdipoR may have anticancer properties in different preclinical models, such as pancreatic and ovarian cancer. To our knowledge, so far no research has been directed at determining the impact of AdipoR on osteosarcoma, the most aggressive and metastatic bone malignancy occurring in childhood and adolescence age. Here, we investigate the possible antitumor effects of AdipoR in osteosarcoma cell lines. MTT and cell growth curve assays clearly indicate that AdipoR inhibits, at different extents, proliferation in both U2OS and Saos-2 osteosarcoma cell lines, the latter being more sensitive. Moreover, flow cytometry-based assays point out a significant G0/G1 phase accumulation and a contemporary S phase decrease in response to AdipoR. Consistent with the different sensitivity, a strong subG1 appearance in Saos-2 after 48 and 72 hours of treatment is also observed. The investigation of the molecular mechanisms highlights a common and initial ERK1/2 activation in response to AdipoR in both Saos-2 and U2OS cells. Interestingly, a simultaneous and dramatic downregulation of p70S6K phosphorylation, one of the main targets of mTORC1 pathway, has also been observed in AdipoR-treated Saos-2, but not in U2OS cells. Importantly, a strengthening of AdipoR-induced effects was reported upon everolimus-mediated mTORC1 perturbation in U2OS cells. In conclusion, our findings provide initial evidence of AdipoR as an anticancer molecule differently affecting various signaling pathways involved in cell cycle and cell death in osteosarcoma cells and encourage the design of future studies to further understand its pattern of activities.

Chlorogenic acid activates ERK1/2 and inhibits proliferation of osteosarcoma cells

Osteosarcoma (OS) is a very aggressive metastatic pediatric and adolescent tumor. Due to its recurrent development of chemotherapy resistance, clinical outcome for OS patients remains poor. Therefore, discovering more effective anticancer agents is needed. Chlorogenic acid (CGA) is a phenolic compound contained in plant-related products that modulates many cellular functions and inhibits cell proliferation in several cancer types. However, few evidence is available in OS. Here, we investigate the effects of CGA in U2OS, Saos-2, and MG-63 OS cells. By multiple approaches, we demonstrate that CGA acts as anticancer molecule affecting the cell cycle and provoking cell growth inhibition mainly by apoptosis induction. We also provide evidence that CGA strongly activates extracellular-signal-regulated kinase1/2 (ERK1/2). Strikingly, ERK1/2 inhibitor PD98059 sensitizes the cells to CGA. Altogether, our data enforce the evidence of the anticancer activity mediated by CGA and provide the rationale for the development of innovative therapeutic strategies in OS cure.

Mutations in the S-Adenosylmethionine Synthetase Genes SAM1 and SAM2 Differentially Affect Genome Stability in Saccharomyces cerevisiae

Maintenance of genome integrity is a crucial cellular focus that involves a wide variety of proteins functioning in multiple processes. Defects in many different pathways can result in genome instability, a hallmark of cancer. Utilizing a diploid Saccharomyces cerevisiae model, we previously reported a collection of gene mutations that affect genome stability in a haploinsufficient state. In this work we explore the effect of gene dosage on genome instability for one of these genes and its paralog; SAM1 and SAM2 These genes encode S-Adenosylmethionine (AdoMet) synthetases, responsible for the creation of AdoMet from methionine and ATP. AdoMet is the universal methyl donor for methylation reactions and is essential for cell viability. It is the second most used cellular enzyme substrate and is exceptionally well-conserved through evolution. Mammalian cells express three genes, MAT1A, MAT2A, and MAT2B, with distinct expression profiles and functions. Alterations to these AdoMet synthetase genes, and AdoMet levels, are found in many cancers, making them a popular target for therapeutic intervention. However, significant variance in these alterations are found in different tumor types, with the cellular consequences of the variation still unknown. By studying this pathway in the yeast system, we demonstrate that losses of SAM1 and SAM2 have different effects on genome stability through distinctive effects on gene expression and AdoMet levels, and ultimately separate effects on the methyl cycle. Thus, this study provides insight into the mechanisms by which differential expression of the SAM genes have cellular consequences that affect genome instability.

Metabolic Dysregulations and Epigenetics: A Bidirectional Interplay that Drives Tumor Progression

Cancer has been considered, for a long time, a genetic disease where mutations in keyregulatory genes drive tumor initiation, growth, metastasis, and drug resistance. Instead, theadvent of high-throughput technologies has revolutionized cancer research, allowing to investigatemolecular alterations at multiple levels, including genome, epigenome, transcriptome, proteome,and metabolome and showing the multifaceted aspects of this disease. The multi-omics approachesrevealed an intricate molecular landscape where different cellular functions are interconnected andcooperatively contribute to shaping the malignant phenotype. Recent evidence has brought to lighthow metabolism and epigenetics are highly intertwined, and their aberrant crosstalk can contributeto tumorigenesis. The oncogene-driven metabolic plasticity of tumor cells supports the energeticand anabolic demands of proliferative tumor programs and secondary can alter the epigeneticlandscape via modulating the production and/or the activity of epigenetic metabolites. Conversely,epigenetic mechanisms can regulate the expression of metabolic genes, thereby altering themetabolome, eliciting adaptive responses to rapidly changing environmental conditions, andsustaining malignant cell survival and progression in hostile niches. Thus, cancer cells takeadvantage of the epigenetics-metabolism crosstalk to acquire aggressive traits, promote cellproliferation, metastasis, and pluripotency, and shape tumor microenvironment. Understandingthis bidirectional relationship is crucial to identify potential novel molecular targets for theimplementation of robust anti-cancer therapeutic strategies.

S-Adenosylmethionine Affects Cell Cycle Pathways and Suppresses Proliferation in Liver Cells

S-Adenosylmethionine (SAMe) is a kind of common liver-protection medicine. Recent studies have shown that SAMe has the inhibitory effects on hepatocellular carcinoma (HCC). But the specific mechanism has not been elucidated. Here, we examine the effects and relevant mechanisms of SAMe on human hepatocellular carcinoma cell HepG2 and mouse hepatocyte AML12. We applied the technique of RNA sequencing (RNA-Seq) to identify the differentially expressed genes between HepG2 cells which were treated with SAMe or not. And western blot and Quantitative RT-PCR was used to confirm some of these genes. To investigate the response to SAMe treatment, cell proliferation assay (MTS) and flow cytometry-based assays were carried out. A total of 472 SAMe-related genes were identified by RNA-Seq. We found that differentially expressed genes were enriched in cell cycle related signaling pathway significantly by the KEGG and GO Pathway enrichment analysis. Through the construction of protein-protein interaction network, we observed the module associated with cell cycle is in the core of the whole network. All these results implied that cell cycle pathway may be very important in the regulation of SAMe effected on HepG2 cells. Then the RNA-Seq-characterized genes involved in cell cycle (MCM3, MCM4, and E2F1) were confirmed by Western blot and Quantitative RT-PCR in HepG2 and AML12 cells. MTS analysis showed that SAMe could diminish cell proliferation. And flow cytometry-based assays indicated that treatment with SAMe altered cell cycle kinetic S phase cell cycle arrest. Altogether, our data uncovered the evidence of the antiproliferative action of SAMe in liver cells, and SAMe could lead to cell cycle inhibition by up-regulating MCM3, MCM4 and E2F1 expression. It provided an important theoretical basis for the clinical chemoprevention and treatment in HCC of SAMe.

HSP90 Molecular Chaperones, Metabolic Rewiring, and Epigenetics: Impact on Tumor Progression and Perspective for Anticancer Therapy

Heat shock protein 90 (HSP90) molecular chaperones are a family of ubiquitous proteins participating in several cellular functions through the regulation of folding and/or assembly of large multiprotein complexes and client proteins. Thus, HSP90s chaperones are, directly or indirectly, master regulators of a variety of cellular processes, such as adaptation to stress, cell proliferation, motility, angiogenesis, and signal transduction. In recent years, it has been proposed that HSP90s play a crucial role in carcinogenesis as regulators of genotype-to-phenotype interplay. Indeed, HSP90 chaperones control metabolic rewiring, a hallmark of cancer cells, and influence the transcription of several of the key-genes responsible for tumorigenesis and cancer progression, through either direct binding to chromatin or through the quality control of transcription factors and epigenetic effectors. In this review, we will revise evidence suggesting how this interplay between epigenetics and metabolism may affect oncogenesis. We will examine the effect of metabolic rewiring on the accumulation of specific metabolites, and the changes in the availability of epigenetic co-factors and how this process can be controlled by HSP90 molecular chaperones. Understanding deeply the relationship between epigenetic and metabolism could disclose novel therapeutic scenarios that may lead to improvements in cancer treatment.

Metabolic Intermediates in Tumorigenesis and Progression

Traditional antitumor drugs inhibit the proliferation and metastasis of tumour cells by restraining the replication and expression of DNA. These drugs are usually highly cytotoxic. They kill tumour cells while also cause damage to normal cells at the same time, especially the hematopoietic cells that divide vigorously. Patients are exposed to other serious situations such as a severe infection caused by a decrease in the number of white blood cells. Energy metabolism is an essential process for the survival of all cells, but differs greatly between normal cells and tumour cells in metabolic pathways and metabolic intermediates. Whether this difference could be used as new therapeutic target while reducing damage to normal tissues is the topic of this paper. In this paper, we introduce five major metabolic intermediates in detail, including acetyl-CoA, SAM, FAD, NAD⁺ and THF. Their contents and functions in tumour cells and normal cells are significantly different. And the possible regulatory mechanisms that lead to these differences are proposed carefully. It is hoped that the key enzymes in these regulatory pathways could be used as new targets for tumour therapy.

Velvet Antler compounds targeting major cell signaling pathways in osteosarcoma - a new insight into mediating the process of invasion and metastasis in OS

Velvet antler is the only renewable bone tissue of mammalian animals, which consists of a variety of growth factors, amino acids and polypeptides. But the mechanism of high-speed proliferation without carcinogenesis is still mystifying. The previous study of this work found that the velvet antler peptides (VAP) could not only inhibit the proliferation and migration of osteosarcoma cell lines MG-63 and U2OS, but also induced U2OS apoptosis and inhibited MG-63 epithelial-mesenchymal transition (EMT) through TGF-β and Notch pathways. These results lead us to conclude that VAP has the potential ability to mediate osteosarcoma cells by regulating related signaling pathways and growth factors. Therefore, finding a new appropriate inhibitor for OS is a valuable research direction, which will give patients a better chance to receive proper therapy. From an applied perspective, this review summarized the effects of velvet antler, genes, growth factors and research progress of relative pathways and genes of osteosarcoma, which are poised to help link regenerative molecular biology and regenerative medicine in osteosarcoma pathogenesis.

Targeting DNA Hypomethylation in Malignancy by Epigenetic Therapies

DNA methylation is a chemically reversible epigenetic modification that regulates the chromatin structure and gene expression, and thereby takes part in various cellular processes like embryogenesis, genomic imprinting, X-chromosome inactivation, and genome stability. Alterations in the normal methylation levels of DNA may contribute to the development of pathological conditions like cancer. Even though both hypo- and hypermethylation-mediated abnormalities are prevalent in the cancer genome, the field of cancer epigenetics has been more focused on targeting hypermethylation. As a result, DNA hypomethylation-mediated abnormalities remained relatively less explored, and currently, there are no approved drugs that can be clinically used to target hypomethylation. Understanding the precise role of DNA hypomethylation is not only crucial from a mechanistic point of view but also for the development of pharmacological agents that can reverse the hypomethylated state of the DNA. This chapter focuses on the causes and impact of DNA hypomethylation in the development of cancer and describes the possible ways to pharmacologically target it, especially by using a naturally occurring physiologic agent S-adenosylmethionine (SAM).

AdoMet triggers apoptosis in head and neck squamous cancer by inducing ER stress and potentiates cell sensitivity to cisplatin

S-Adenosyl-l-methionine (AdoMet) is a naturally and widely occurring sulfonium compound that plays a primary role in cell metabolism and acts as the principal methyl donor in many methylation reactions. AdoMet also exhibits antiproliferative and proapoptotic activities in different cancer cells. However, the molecular mechanisms underlying the effects exerted by AdoMet have only been partially studied. In the current study, we evaluated the antiproliferative effect of AdoMet on Cal-33 oral and JHU-SCC-011 laryngeal squamous cancer cells to define the underlying mechanisms. We demonstrated that AdoMet induced apoptosis in Cal-33 and JHU-SCC-011 cells, involving a caspase-dependent mechanism paralleled by an increased Bax/Bcl-2 ratio. Moreover, we showed, for the first time, that AdoMet induced ER-stress in Cal-33 cells and activated the unfolded protein response, which can be responsible for apoptosis induction through the activation of CHOP and JNK. In addition, AdoMet-induced ER-stress was followed by autophagy with a consistent increase in the levels of the autophagic marker LC3B-II, which was indeed potentiated by the autophago-lysosome inhibitor chloroquine. As both escape from apoptosis and decreased activation of JNK are mechanisms of resistance to cisplatin (cDPP), an agent usually used in cancer therapy, we have evaluated the effects of AdoMet in combination with cDPP on Cal-33 cells. Our data showed that the combined treatment resulted in a strong synergism in inhibiting cell proliferation and in enhancing apoptosis via intrinsic mechanism. These results demonstrate that AdoMet has ER-stress-mediated antiproliferative activity and synergizes with cDDP on cell growth inhibition, thus providing the basis for its use in new anticancer strategies.

S-Adenosylmethionine regulates apoptosis and autophagy in MCF-7 breast cancer cells through the modulation of specific microRNAs

Background

To get insight into the molecular mechanisms underlying the anti-tumor activity of S-adenosyl-l-methionine (AdoMet), we analyzed AdoMet-induced modulation of microRNAs (miRNAs) expression profile in MCF-7 breast cell line and its correlation with cancer-related biological pathways.

Methods

MiRNA expression profiling was performed using a TaqMan MiRNA Array, following 500 µM AdoMet-treatment. The results were confirmed by Quantitative real-time PCR analysis. MCF-7 were transfected with miR-34a, miR-34c and miR-486-5p, mimics and inhibitors in presence or not of 500 µM AdoMet for 72 h. Apoptosis and autophagy were analyzed by flow cytometry and the modulation of the main antiproliferative signaling pathways were evaluated by Western blotting. The potential mRNA targets for each miRNA were identified by the TargetScan miRNA target prediction software.

Results

Twenty-eight microRNAs resulted differentially expressed in AdoMet-treated MCF-7 cells compared to control cells. Among them, miRNA-34a and miRNA-34c were up-regulated while miRNA-486-5p was down-regulated. Moreover, we confirmed the ability of AdoMet to regulate these miRNAs in MDA-MB 231 breast cancer cell line. We demonstrate that, in MCF7 cells, the combination of either miR-34a or miR-34c mimic with AdoMet greatly potentiated the pro-apoptotic effect of AdoMet, by a caspase-dependent mechanism and activates p53 acetylation by inhibiting SIRT1 and HDAC1 expression. We also showed that miR-486-5p inhibitor induces autophagy and enhances AdoMet-induced autophagic process by increasing PTEN expression and by inhibiting AKT signaling.

Conclusions

Our findings provide the first evidence that AdoMet can regulate miRNA expression in MCF-7 increasing our knowledge on the molecular basis of the antitumor effect of the sulfonium compound and suggest the use of AdoMet as an attractive miRNA-mediated chemopreventive and therapeutic strategy in breast cancer.

Integrative proteomics and immunochemistry analysis of the factors in the necrosis and repair in acetaminophen-induced acute liver injury in mice

Acetaminophen (APAP) overdose-induced acute liver injury (AILI) is a significant clinical problem worldwide, the hepatotoxicity mechanisms are well elucidated, but the factors involved in the necrosis and repair still remain to be investigated. APAP was injected intraperitoneally in male Institute of Cancer Research (ICR) mice. Quantitative proteome analysis of liver tissues was performed by 2-nitrobenzenesulfenyl tagging, two-dimensional-nano high-performance liquid chromatography separation, and matrix-assisted laser desorption/ionization-time of flight mass spectrometry analysis. Diffrenetial proteins were verified by the immunochemistry method. 36 and 44 differentially expressed proteins were identified, respectively, at 24 hr after APAP (200 or 300 mg·kg ^-1 ) administration. The decrease in the mitochondrial protective proteins Prdx6, Prdx3, and Aldh2 accounted for the accumulation of excessive reactive oxygen species (ROS) and aldehydes, impairing mitochondria structure and function. The Gzmf combined with Bax and Apaf-1 jointly contributed to the necrosis. The blockage of Stat3 activation led to the overexpression of unphosphorylated Stat3 and the overproduction of Bax. The overexpression of unphosphorylated Stat3 represented necrosis; the alternation from Stat3 to p-Stat3 in necrotic regions represented hepatocytes from death to renewal. The high expressions of P4hα1, Ncam, α-SMA, and Cygb were involved in the liver repair, they were not only the markers of activated HSC but also represented an intermediate stage of hepatocytes from damage or necrosis to renewal. Our data provided a comprehensive report on the profile and dynamic changes of the liver proteins in AILI; the involvement of Gzmf and the role of Stat3 in necrosis were revealed; and the role of hepatocyte in liver self-repair was well clarified.

S-Adenosylmethionine-mediated apoptosis is potentiated by autophagy inhibition induced by chloroquine in human breast cancer cells

The naturally occurring sulfonium compound S-adenosyl-L-methionine (AdoMet) is an ubiquitous sulfur-nucleoside that represents the main methyl donor in numerous methylation reactions. In recent years, it has been shown that AdoMet possesses antiproliferative properties in various cancer cells, but the molecular mechanisms at the basis of the effect induced by AdoMet have been only in part investigated. In the present study, we found that AdoMet strongly inhibited the proliferation of breast cancer cells MCF-7 by inducing both autophagy and apoptosis. AdoMet consistently enhanced the levels of the autophagy markers beclin-1 and LC3B-II, and caused a significant increase of pro-apoptotic Bax/Bcl-2 ratio paralleled by poly (ADP ribose) polymerase (PARP) and caspase 9, and 6 cleavage. Notably, AdoMet, already at low doses, raised the percentage of cells in G₂ /M phase of cell cycle by down-regulating the expression of cell cycle-regulatory proteins cyclin B and cyclin E with a remarkable increase of p53, p27, and p21. We also evaluated the combination of AdoMet and the autophagy inhibitor chloroquine (CLC) showing that autophagy block is synergistic in inducing both growth inhibition and apoptosis. These effects were paralleled by a strong inhibition of the activity of AKT and of the downstream effector mTOR and by an increased cleavage of caspase-6 and PARP. These data suggest, for the first time, that autophagy can act as an escape mechanism from the apoptotic activity of AdoMet, and that AdoMet could be used in combination with CLC or its analogs in the treatment of breast cancer.

Adiponectin down-regulates CREB and inhibits proliferation of A549 lung cancer cells

INTRODUCTION

Adipokines are known to play a relevant role in a number of cancer related molecular pathways. Adiponectin is a major adipokine with anti-inflammatory and beneficial metabolic actions. Furthermore, it has been shown to exert anti-carcinogenic effects in various tumor models and some clinical studies suggested an inverse relationship between circulating levels of adiponectin and an increased risk for development of malignancies. On the other hand, the cyclic AMP response element binding (CREB) transcription factor has been clearly linked to lung cancer.

METHODS

we analyzed cell proliferation, cell cycle of A549 cells treated with adiponectin as well as CREB activation status in human lung adenocarcinoma A549 cells and in non-small cell lung cancer (NSCLC) samples.

RESULTS

adiponectin treatment, at concentrations ranging between 5 and 50 μg/ml mimicking human serum levels, has a significant effect on reducing tumor cell proliferation of A549 cells, mainly by altering cell cycle progression. Importantly, we provide evidence that adiponectin clearly inhibits in a dose- and time-dependent manner CREB phosphorylation (activation) and, at least in part, also the level of CREB protein itself, preceding and accompanying the anti-proliferative effects in response to adiponectin. Moreover, in agreement with previous studies demonstrating that CREB over-expression occurs in many tumors, we also show by western-blotting from lung specimen that CREB is significantly up-regulated in NSCLC samples compared to adjacent normal tissues from six patients.

CONCLUSIONS

Overall, our results represent the first evidence of CREB inhibition by adiponectin and may provide new insight into therapeutic strategies for lung cancer.

Novel immunoassays to detect methionine adenosyltransferase activity and quantify S-adenosylmethionine

We present a novel real-time immunoassay to measure methionine adenosyltransferase (MAT) activity that integrates the MAT-catalyzed reaction of Met and adenosine triphosphate to produce S-adenosylmethionine (SAM) and a highly sensitive immunoassay to specifically quantify SAM simultaneously. The cellular localization of SAM and S-adenosylhomocysteine varies with cell proliferation status: in normal cells, they are found mostly in the cytoplasm, but localize to the nucleus in proliferating cells. MAT-I/III activity is stimulated by Met, but inhibited by S-nitrosoglutathione, and the methylation index (MI) increases after Met stimulation of L02 cells. Met and S-nitrosoglutathione inhibit MAT-II activity, and the MI decreases after Met stimulation of HepG2 cells. The method described provides a significant advancement in the field for the measurement of MAT activity under various conditions.

JAK-STAT signaling in cancer: From cytokines to non-coding genome

In the past decades, studies of the Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) signaling have uncovered highly conserved programs linking cytokine signaling to the regulation of essential cellular mechanisms such as proliferation, invasion, survival, inflammation and immunity. Inhibitors of the JAK/STAT pathway are used for treatment of autoimmune diseases, such as rheumatoid arthritis or psoriasis. Aberrant JAK/STAT signaling has been identified to contribute to cancer progression and metastatic development. Targeting of JAK/STAT pathway is currently one of the most promising therapeutic strategies in prostate cancer (PCa), hematopoietic malignancies and sarcomas. Notably, newly identified regulators of JAK/STAT signaling, the non-coding RNAs transcripts and their role as important targets and potential clinical biomarkers are highlighted in this review. In addition to the established role of the JAK/STAT signaling pathway in traditional cytokine signaling the non-coding RNAs add yet another layer of hidden regulation and function. Understanding the crosstalk of non-coding RNA with JAK/STAT signaling in cancer is of critical importance and may result in better patient stratification not only in terms of prognosis but also in the context of therapy.

GADD45β induction by S-adenosylmethionine inhibits hepatocellular carcinoma cell proliferation during acute ischemia-hypoxia

Growth arrest DNA damage-inducible gene 45β (GADD45β), which influences cell growth, apoptosis and cellular response to DNA damage, is downregulated in hepatocellular carcinoma (HCC). S-adenosylmethionine (SAMe) serves as an essential methyl donor in multiple metabolic pathways and is a polyamine and glutathione (GSH) precursor. In this study, we assessed the roles of GADD45β and SAMe in cell survival during acute ischemia-hypoxia (I/H). SAMe treatment induced growth of HL-7702 normal hepatic cells, but decreased the viability of HepG2 (p53 wild-type) and Hep3B (p53 null) HCC cells. Cells were exposed to I/H with or without SAMe pre-treatment. I/H exposure alone triggered HCC cell proliferation promoted by autophagy. SAMe pre-treatment restored GADD45β expression and activated HCC cell apoptosis and eliminated I/H-induced HCC cell proliferation. p53 loss blunted the response to SAMe and I/H exposure in Hep3B cells; thus, the inhibitory effect of SAMe on cell proliferation may be reduced in p53-null cells as compared to wild-type cells. These results indicate that GADD45β induction by SAMe inhibits HCC cell proliferation during I/H as a result of increased apoptosis, and that SAMe also protects normal hepatocytes from apoptotic cell death and promotes normal cell regeneration. SAMe should be considered a potential therapeutic agent for the management of HCC.