Effects of SIRT1 silencing on viability, invasion and metastasis of human glioma cell lines

Irradiated riboflavin over nonradiated one: Potent antimigratory, antiproliferative and cytotoxic effects on glioblastoma cells

Riboflavin is a water-soluble yellowish vitamin and is controversial regarding its effect on tumour cells. Riboflavin is a powerful photosensitizer that upon exposure to radiation, undergoes an intersystem conversion with molecular oxygen, leading to the production of ROS. In the current study, we sought to ascertain the impact of irradiated riboflavin on C6 glioblastoma cells regarding proliferation, cell death, oxidative stress and migration. First, we compared the proliferative behaviour of cells following nonradiated and radiated riboflavin. Next, we performed apoptotic assays including Annexin V and caspase 3, 7 and 9 assays. Then we checked on oxidative stress and status by flow cytometry and ELISA kits. Finally, we examined inflammatory change and levels of MMP2 and SIRT1 proteins. We caught a clear antiproliferative and cytotoxic effect of irradiated riboflavin compared to nonradiated one. Therefore, we proceeded with our experiments using radiated riboflavin. In all apoptotic assays, we observed a dose-dependent increase. Additionally, the levels of oxidants were found to increase, while antioxidant levels decreased following riboflavin treatment. In the inflammation analysis, we observed elevated levels of both pro-inflammatory and anti-inflammatory cytokines. Additionally, after treatment, we observed reduced levels of MMP2 and SIRT. In conclusion, radiated riboflavin clearly demonstrates superior antiproliferative and apoptotic effects on C6 cells at lower doses compared to nonradiated riboflavin.

Combination of SIX4-siRNA and temozolomide inhibits the growth and migration of A-172 glioblastoma cancer cells

Glioblastoma is one of the most common and invasive types of primary brain malignancies in adults, accounting for 45.5% of malignancies. Its annual prevalence is low compared to other cancers. The survival rate of this disease is about 14 months after diagnosis. Temozolomide (TMZ) is a common chemotherapy drug used to treatment of glioblastoma, but drug resistance against this drug is an important barrier to successful treatment of this cancer. Today, siRNAs play a significant role in cancer treatment. SIX4 is a transcriptional regulatory molecule that can act as a transcriptional suppressor and an activator in target genes involved in differentiation, migration, and cell survival processes. The aim of this study was to evaluate the effect of SIX4-siRNA on A-172 glioblastoma cells, its role as a tumor suppressor, and its combination with TMZ. We studied the cytotoxic effect of the SIX4-siRNA and TMZ on A-172 cells using the MTT assay investigated their effect on apoptosis and cell cycle of A-172 cells used wound healing assays to assess their effect on cell migration. Finally, we used qRT-PCR to study the mRNA expression levels of genes involved in apoptosis and migration of tumoral cells after treatments. Based on our results, silencing SIX4-siRNA expression reduced the cell viability of A-172 cells and sensitize these cells to TMZ. Furthermore, we observed an increase in apoptosis and cell cycle arrest, and a decrease in migration. Bax and caspase-9 overexpression and BCL2 and MMP9 downregulation were detected in the combination of SIX4-siRNA and TMZ. According to our results, the combination of SIX4-siRNA and TMZ can be a very useful strategy for successful glioblastoma treatment.

Sirtuin1 (SIRT1) is involved in the anticancer effect of black raspberry anthocyanins in colorectal cancer

PURPOSE

Abnormal acetylation modification is a common epigenetic change in tumorigenesis and is closely related to the progression of colorectal cancer (CRC). Our previous studies have suggested that black raspberry (BRB) anthocyanins have a significant chemopreventive effect against CRC. This study investigated whether protein acetylation plays an important role in BRB anthocyanins-mediated regulation of CRC progression.

METHODS

We used the AOM-induced CRC mouse model and the CRC cell lines SW480 and Caco-2 to explore the potential role of acetylation of histone H4 and NF-κB signaling pathway-related proteins (non-histone proteins) in the antitumor process mediated by BRB anthocyanins. The expression of related proteins was detected by western blot. ROS level was detected by immunofluorescence.

RESULTS

BRB anthocyanins affected the acetylation level by down-regulating the expression of Sirtuin1 (SIRT1) and up-regulating the expression of MOF and EP300. The acetylation level of lysine sites on histone H4 (H4K5, H4K12 and H4K16) was increased. Furthermore, following BRB anthocyanins treatment, the expression of ac-p65 was significantly up-regulated and the NF-κB signal pathway was activated, which in turn up-regulated Bax expression and inhibited Bcl-2, cyclin-D1, c-myc and NLRP3 expression to promote CRC cell cycle arrest, apoptosis and relieve inflammation.

CONCLUSION

The findings suggested that protein acetylation could play a critical role in BRB anthocyanins-regulated CRC development.

The Mechanistic Roles of Sirtuins in Breast and Prostate Cancer

Simple Summary

There are diverse reports of the dual role of sirtuin genes and proteins in breast and prostate cancers. This review discusses the current information on the tumor promotion or suppression roles of SIRT1–7 in breast and prostate cancers. Precisely, we highlight that sirtuins regulate various proteins implicated in proliferation, apoptosis, autophagy, chemoresistance, invasion, migration, and metastasis of both breast and prostate cancer. We also provide evidence of the direct regulation of sirtuins by miRNAs, highlighting the consequences of this regulation in breast and prostate cancer. Overall, this review reveals the potential value of sirtuins as biomarkers and/or targets for improved treatment of breast and prostate cancers.

Abstract

Mammalian sirtuins (SIRT1–7) are involved in a myriad of cellular processes, including apoptosis, proliferation, differentiation, epithelial-mesenchymal transition, aging, DNA repair, senescence, viability, survival, and stress response. In this review, we discuss the current information on the mechanistic roles of SIRT1–7 and their downstream effects (tumor promotion or suppression) in cancers of the breast and prostate. Specifically, we highlight the involvement of sirtuins in the regulation of various proteins implicated in proliferation, apoptosis, autophagy, chemoresistance, invasion, migration, and metastasis of breast and prostate cancer. Additionally, we highlight the available information regarding SIRT1–7 regulation by miRNAs, laying much emphasis on the consequences in the progression of breast and prostate cancer.

The role of miRNA-624-5p in congenital hypothyroidism and its molecular mechanism by targeting SIRT1

BACKGROUND

Accumulating reports evidenced that congenital hypothyroidism (CH) is a kind of endocrine diseases caused by thyroid hormone imperfection. MicroRNAs (miRNAs) were confirmed to exhibit protective functions in CH progression. However, the functions and latent mechanism of microRNA-624-5p (miR-624-5p) in CH remains unknown.

OBJECTIVE

This report was designed to illustrate the potential molecular mechanisms of miR-624-5p on CH.

METHODS

Rats were induced by 50 mg/day propylthiouracil to conduct CH models. Free thyroxine (fT4) and thyroid-Stimulating hormone (TSH) concentrations were measured to confirm CH model conduction. The direct target of miR-624-5p was predicted and verified by Starbase and dual luciferase reporter assay. Besides, the levels of miR-624-5p and sirtuin1 (SIRT1) in hippocampus or hippocampal neuronal cells were assessed using quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assays. Then CH rat behaviors were evaluated using open field test (OFT) and forced swim test (FST). Furthermore, neuronal cells viability and apoptosis were checked using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry.

RESULTS

qRT-PCR assay suggested that miR-624-5p was up-regulated and SIRT1 was low-expressed in hippocampus tissues of CH rats. SIRT1 was a direct target of miR-624-5p. MiR-624-5p inhibitor signally enhanced fT4 levels and reduced TSH levels in the plasma of CH rats, and improved CH rat depressive behaviors by targeting SIRT1. Moreover, our data also revealed that miR-624-5p inhibitor increased cell viability and reduced apoptotic neuronal cells, which was reversed by silencing of SIRT1.

CONCLUSIONS

Taken together, this research demonstrated that miR-624-5p serves as a promising target for CH treatment.

Resveratrol's Anti-Cancer Effects through the Modulation of Tumor Glucose Metabolism

Simple Summary

The prevention and treatment of cancer is an ongoing medical challenge. In the context of personalized medicine, the well-studied polyphenol resveratrol could complement classical tumor therapy. It may affect key processes such as inflammation, angiogenesis, proliferation, metastasis, glucose metabolism, and apoptosis in various cancers because resveratrol acts as a multi-targeting agent by modulating multiple signal transduction pathways. This review article focuses on resveratrol’s ability to modify tumor glucose metabolism and its associated therapeutic capacity. Resveratrol reduces glucose uptake and glycolysis by affecting Glut1, PFK1, HIF-1α, ROS, PDH, and the CamKKB/AMPK pathway. It also inhibits cell growth, invasion, and proliferation by targeting NF-kB, Sirt1, Sirt3, LDH, PI-3K, mTOR, PKM2, R5P, G6PD, TKT, talin, and PGAM. In addition, resveratrol induces apoptosis by targeting integrin, p53, LDH, and FAK. In conclusion, resveratrol has many potentials to intervene in tumor processes if bioavailability can be increased and this natural compound can be used selectively.

Abstract

Tumor cells develop several metabolic reprogramming strategies, such as increased glucose uptake and utilization via aerobic glycolysis and fermentation of glucose to lactate; these lead to a low pH environment in which the cancer cells thrive and evade apoptosis. These characteristics of tumor cells are known as the Warburg effect. Adaptive metabolic alterations in cancer cells can be attributed to mutations in key metabolic enzymes and transcription factors. The features of the Warburg phenotype may serve as promising markers for the early detection and treatment of tumors. Besides, the glycolytic process of tumors is reversible and could represent a therapeutic target. So-called mono-target therapies are often unsafe and ineffective, and have a high prevalence of recurrence. Their success is hindered by the ability of tumor cells to simultaneously develop multiple chemoresistance pathways. Therefore, agents that modify several cellular targets, such as energy restriction to target tumor cells specifically, have therapeutic potential. Resveratrol, a natural active polyphenol found in grapes and red wine and used in many traditional medicines, is known for its ability to target multiple components of signaling pathways in tumors, leading to the suppression of cell proliferation, activation of apoptosis, and regression in tumor growth. Here, we describe current knowledge on the various mechanisms by which resveratrol modulates glucose metabolism, its potential as an imitator of caloric restriction, and its therapeutic capacity in tumors.

Synergistic Effect of Dietary Betaines on SIRT1-Mediated Apoptosis in Human Oral Squamous Cell Carcinoma Cal 27

Simple Summary

Betaines are important human nutrients widely distributed in plants, animals, and dietary sources. δ-valerobetaine (δVB) is a naturally occurring betaine with antioxidant, anti-inflammatory and anticancer activities. The aim of our study was to investigate the possible synergism between δVB and the structurally related γ-butyrobetaine (γBB) by testing the in vitro anticancer activity in head and neck squamous cell carcinomas. Combined δVB and γBB caused a marked inhibition of cell proliferation and induction of apoptosis in Cal 27 cells. The increased reactive oxygen species accumulation influenced the nuclear expression of SIRT1. Gene silencing with small interfering RNA confirmed the role of SIRT1 in the apoptotic cell death. Synergism of δVB and γBB is useful for novel strategies to optimize their content in meat, milk and dairy products to sustain human health and wellbeing.

Abstract

Betaines are food components widely distributed in plants, animals, microorganisms, and dietary sources. Among betaines, δ-valerobetaine (N,N,N-trimethyl-5-aminovaleric acid, δVB) shares a metabolic pathway common to γ-butyrobetaine (γBB). The biological properties of δVB are particularly attractive, as it possesses antioxidant, anti-inflammatory and anticancer activities. Here, we investigated the possible synergism between δVB and the structurally related γBB, to date unexplored, by testing the in vitro anticancer activity in head and neck squamous cell carcinoma cell lines, FaDu, UM-SCC-17A and Cal 27. Among cell lines tested, results indicated that betaines showed the highest effect in reducing Cal 27 cell proliferation up to 72 h (p < 0.01). This effect was enhanced when betaines were administered in combination (δVB plus γBB) (p < 0.001). Inhibition of cell growth by δVB plus γBB involved reactive oxygen species (ROS) accumulation, upregulation of sirtuin 1 (SIRT1), and apoptosis (p < 0.001). SIRT1 gene silencing by small interfering RNA decreased the apoptotic effect of δVB plus γBB by modulating downstream procaspase-3 and cyclin B1 (p < 0.05). These findings might have important implications for novel prevention strategies for tongue squamous cell carcinoma by targeting SIRT1 with naturally occurring betaines.

Clinical and Biological Significances of a Methyltransferase-Related Signature in Diffuse Glioma

Methylation of DNA, RNA or protein is a reversible modification. The proteins and genes that regulate this modification can be a candidate target for tumor therapy. However, the characteristics of methyltransferase related genes in glioma remain obscure. In this study, we systematically analyzed the relationship between methyltransferase-related genes expression profiles and outcomes in glioma patients based on The Cancer Genome Atlas and Chinese Glioma Genome Atlas RNA sequencing datasets. Consensus clustering identified two robust groups with significantly different pathological features and prognosis. Then a methyltransferase-related risk signature was built by a Cox proportional hazards model with elastic net penalty. Moreover, the risk score is associated with patients' clinical and molecular features and can be used as an independent prognostic indicator for patients with glioma. Furthermore, genes associated with the high-risk group were involved in various aspects of the malignant progression of glioma via Gene Ontology analysis and Gene Set Enrichment Analysis. In summary, our study identified a methyltransferase-related risk signature for predicting the prognosis of gliomas.

Monocarboxylate Transporter 1 in Brain Diseases and Cancers

Background:

Monocarboxylate Transporter 1 (MCT1), an important membrane transport protein, mediates the translocation of monocarboxylates together with protons across biological membranes. Due to its pathological significance, MCT1 plays an important role in the progression of some diseases, such as brain diseases and cancers.

Methods:

We summarize the general description of MCT1 and provide a comprehensive understanding of the role of MCT1 in brain diseases and cancers. Furthermore, this review discusses the opportunities and challenges of MCT1- targeting drug-delivery systems in the treatment of brain diseases and cancers.

Results:

In the brain, loss of MCT1 function is associated with pathologies of degeneration and injury of the nervous system. In tumors, MCT1 regulates the activity of signaling pathways and controls the exchange of monocarboxylates in aerobic glycolysis to affect tumor metabolism, proliferation and invasion. Meanwhile, MCT1 also acts as a good biomarker for the prediction and diagnosis of cancer progressions.

Conclusion:

MCT1 is an attractive transporter in brain diseases and cancers. Moreover, the development of MCT1- based small molecule drugs and MCT1 inhibitors in the clinic is promising. This review systematically summarizes the basic characteristics of MCT1 and its role in brain diseases and cancers, laying the foundation for further research on MCT1.

tert-Butylhydroquinone Treatment Alleviates Contrast-Induced Nephropathy in Rats by Activating the Nrf2/Sirt3/SOD2 Signaling Pathway

Oxidative stress plays a critical role in the pathophysiology of contrast-induced nephropathy (CIN). Since the specific treatment of CIN remains an unmet medical need, it is imperative to find an effective strategy against the clinical management of CIN. The transcription factor Nrf2 is known to regulate antioxidative stress response. The aim of the present study was to assess the effects of tert-butylhydroquinone (t-BHQ), an activator of Nrf2, in the prevention of CIN and elucidate the underlying mechanism of its action in vitro and in vivo. We established a rat model of CIN and treated the animals with t-BHQ (25 mg/kg). The effects of t-BHQ treatment on CIN rats were elucidated by assessing renal function, HE staining, immunohistochemistry, and western blotting. We also studied the activity of oxidative stress-related markers, such as intracellular ROS level, MDA level, SOD2 activity, and GSH/GSSG ratio. We validated our results by siRNA-mediated silencing of Nrf2 in HK-2 cells exposed to the radiocontrast agent. Treatment with t-BHQ significantly ameliorated the renal function and the histopathological lesions in CIN rats. Further, pretreatment with t-BHQ significantly increased the SOD2 activity and GSH/GSSG ratio and decreased the levels of ROS and MDA in animals subjected to ioversol exposure. In addition, t-BHQ treatment increased the expression of Nrf2, Sirt3, and SOD2 and concomitantly decreased the expression of acetylated-SOD2. When Nrf2-silenced HK-2 cells were exposed to radiocontrast agent, they suffered severe cell oxidative stress, exhibited lower expression of Sirt3 and SOD2, and expressed higher levels of acetylated-SOD2; however, t-BHQ treatment did not affect the protein expression of these indicators in si-Nrf2 HK-2 cells. Our findings suggested that Nrf2 plays an important role in the regulation of the Sirt3/SOD2 antioxidative pathway, and t-BHQ may be a potential agent to ameliorate radiocontrast-induced nephropathy via activating the Nrf2/Sirt3/SOD2 signaling pathway in vitro and in vivo.

The Roles of Sirtuin Family Proteins in Cancer Progression

Sirtuin family members are characterized by either mono-ADP-ribosyltransferase or deacylase activity and are linked to various cancer-related biological pathways as regulators of transcriptional progression. Sirtuins play fundamental roles in carcinogenesis and maintenance of the malignant phenotype, mainly participating in cancer cell viability, apoptosis, metastasis, and tumorigenesis. Although sirtuin family members have a high degree of homology, they may play different roles in various kinds of cancer. This review highlights their fundamental roles in tumorigenesis and cancer development and provides a critical discussion of their dual roles in cancer, namely, as tumor promoters or tumor suppressors.