Effects of caffeine on cell viability and activity of histone deacetylase 1 and histone acetyltransferase in glioma cells

Progress in discovery and development of natural inhibitors of histone deacetylases (HDACs) as anti-cancer agents

The study of epigenetic translational modifications had drawn great interest for the last few decades. These processes play a vital role in many diseases and cancer is one of them. Histone acetyltransferase (HAT) and histone deacetylases (HDACs) are key enzymes involved in the acetylation and deacetylation of histones and ultimately in post-translational modifications. Cancer frequently exhibits epigenetic changes, particularly disruption in the expression and activity of HDACs. It includes the capacity to regulate proliferative signalling, circumvent growth inhibitors, escape cell death, enable replicative immortality, promote angiogenesis, stimulate invasion and metastasis, prevent immunological destruction, and genomic instability. The majority of tumours develop and spread as a result of HDAC dysregulation. As a result, HDAC inhibitors (HDACis) were developed, and they today stand as a very promising therapeutic approach. One of the most well-known and efficient therapies for practically all cancer types is chemotherapy. However, the efficiency and safety of treatment are constrained by higher toxicity. The same has been observed with the synthetic HDACi. Natural products, owing to many advantages over synthetic compounds for cancer treatment have always been a choice for therapy. Hence, naturally available molecules are of particular interest for HDAC inhibition and HDAC has drawn the attention of the research fraternity due to their potential to offer a diverse array of chemical structures and bioactive compounds. This diversity opens up new avenues for exploring less toxic HDAC inhibitors to reduce side effects associated with conventional synthetic inhibitors. The review presents comprehensive details on natural product HDACi, their mechanism of action and their biological effects. Moreover, this review provides a brief discussion on the structure activity relationship of selected natural HDAC inhibitors and their analogues which can guide future research to discover selective, more potent HDACi with minimal toxicity.

Caffeine reduces viability, induces apoptosis, inhibits migration and modulates the CD39/CD73 axis in metastatic cutaneous melanoma cells

We aimed to evaluate the effect of caffeine on viability, apoptosis, migration, redox profile and modulatory effect of the purinergic system of cutaneous melanoma cells. The melanoma cells SK-MEL-28 and non-tumoural CCD-1059sk cells were treated for 24 h with different concentrations of caffeine. Cell viability was evaluated by a biochemical assay and fluorescence microscopy, and flow cytometry assessed apoptosis induction. A wound-healing assay assessed cell migration. The redox profile was evaluated by the levels of markers of reactive oxygen species (ROS), nitric oxide (NOx), total thiols (PSH) and non-protein thiols (NPSH). RT-qPCR and flow cytometry assessed the expression of CD39 and CD73. ATPase/ADPase and AMPase enzyme activities were evaluated by hydrolysis of ATP, ADP and AMP nucleotides. A bioluminescent assay assessed extracellular ATP levels. Caffeine significantly reduced melanoma cell viability and migration and did not affect non-tumoural cells. Caffeine increased ROS levels and improved PSH levels in melanoma cells. Furthermore, caffeine reduced CD39 and CD73 expression, decreased ATP, ADP and AMP nucleotide hydrolysis and increased extracellular ATP levels. We have shown that caffeine reduces metastatic cutaneous melanoma cell viability and migration, induces ROS generation and improves PSH levels. In an unprecedented manner, we also showed that caffeine reduces the expression of CD39 and CD73 and, consequently, ATPase/ADPase/AMPase hydrolytic activity of ectonucleotidases, thus displacing the CD39/CD73 axis and increasing extracellular ATP levels. Therefore, caffeine may be an interesting compound for clinical trials with the CD39/CD73 axis as a therapeutic target.

Effects of energy drinks on myogenic differentiation of murine C2C12 myoblasts

Energy drinks, often advertised as dietary supplements that enhance physical and mental performance, have gained increasing popularity among adolescents and athletes. Several studies on individual ingredients such as caffeine or taurine have reported either adverse or favorable influences on myogenic differentiation, a key process in muscle regeneration to repair microtears after an intense workout session. However, the impact of different energy drinks with various formulas on muscle differentiation has never been reported. This study aims to examine the in vitro effects of various energy drink brands on myogenic differentiation. Murine C2C12 myoblast cells were induced to differentiate into myotubes in the presence of one of eight energy drinks at varying dilutions. A dose-dependent inhibition of myotube formation was observed for all energy drinks, supported by reduced percentage of MHC-positive nuclei and fusion index. Moreover, expression of myogenic regulatory factor MyoG and differentiation marker MCK were also decreased. Furthermore, given the variation in formulas of different energy drinks, there were remarkable differences in the differentiation and fusion of myotubes between energy drinks. This is the first study to investigate the impact of various energy drinks on myogenic differentiation and our results suggest an inhibitory effect of energy drinks in muscle regeneration.

Caffeine improves the cytotoxic effect of dacarbazine on B16F10 murine melanoma cells

OBJECTIVE

Caffeine has been studied as a potentiating agent in chemotherapy against some types of cancer, but there are few reports on its effects on melanoma. This study aimed to investigate caffeine's ability to enhance the effects of dacarbazine in vitro.

MATERIALS AND METHODS

Murine melanoma B16F10 cells were treated 24 h with 1-40 µM caffeine. We evaluated cytotoxicity, DNA damage, apoptosis, and oxidative lesion induced by dacarbazine associated with caffeine. The metabolization of these drugs, as well as immunocytochemical labeling, were also evaluated.

CONCLUSIONS

The pre-treatment with caffeine showed to be more effective. Caffeine potentiated dacarbazine-induced cytotoxic effects by increasing dacarbazine biotransformation, apoptosis, DNA damage, and malondialdehyde levels; also, caffeine reduced Ki67 and ERK1/2 nuclear labeling and increased p53 labeling in B16F10 cells. In our experiment, caffeine promoted modifications associated with dacarbazine metabolism by viable cells potentiating this antineoplastic drug. These promising results should be further evaluated in experimental models in vivo.

Caffeine Inhibits Growth of Temozolomide-Treated Glioma via Increasing Autophagy and Apoptosis but Not via Modulating Hypoxia, Angiogenesis, or Endoplasmic Reticulum Stress in Rats

Thirty rats with glioma were divided into control group, temozolomide (TMZ) group (TMZ 30 mg/kg once daily for 5 day), and TMZ plus Caffeine group (TMZ 30 mg/kg once daily for 5 day and caffeine 100 mg/kg once daily for 2 weeks). The relative tumor fold and expression of hypoxia-induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), neuropilin-1 (NRP-1), CCAAT/enhancer-binding protein homologous protein (CHOP), LC-3A/B, apoptosis-inducing factor-1 (AIF-1), and cleaved caspase three were compared. The relative tumor fold of TMZ plus Caffeine group was lower significantly than that of TMZ group at day 14. HIF-1α, VEGF, NRP-1, and CHOP expressions were not significantly different in the three groups. The LC-3A/B expression of TMZ plus Caffeine group was higher significantly than that of the control group and TMZ group. The AIF expressions of TMZ group and TMZ plus Caffeine group were higher significantly than that of the control group. The caspase-3 expression of TMZ plus Caffeine group was higher significantly than that of the control group and TMZ group. In conclusions, the inhibitory effect of caffeine on TMZ-treated glioma might be associated with increasing expressions of autophagy- and apoptosis-related genes.

Effects of Cinnamaldehyde on the Viability and Expression of Chemokine Receptor Genes in Temozolomide-treated Glioma Cells

BACKGROUND/AIM

The effects of cinnamaldehyde on glioma are still unclear. We aimed to investigate the effects of cinnamaldehyde on the viability and expression of chemokine receptors CXCR4 and CXCR7 in temozolomide (TMZ)-treated glioma cells.

MATERIALS AND METHODS

Cell viability and CXCR4 and CXCR7 expression were measured by western blotting at 72 h after treatment with various concentrations of cinnamaldehyde and TMZ.

RESULTS

Cell viability was significantly lower after treatment with 300 μM TMZ, 50 μM cinnamaldehyde, 75 μM cinnamaldehyde, or combined treatment with 300 μM TMZ plus 50 μM or 75 μM cinnamaldehyde than after no treatment (i.e., without TMZ or cinnamaldehyde); and significantly lower after combined treatment with 300 μM TMZ plus 75 μM cinnamaldehyde but not 50 μM cinnamaldehyde, than treatment with 300 μM TMZ alone. Western blotting showed that either single treatments or combined treatments had lower CXCR4 expression (compared to the no-treatment control). Compared to 300 μM TMZ alone, both combined treatment of 300 μM TMZ plus 50 μM cinnamaldehyde or 75 μM cinnamaldehyde had significantly lowered CXCR4 expression. However, CXCR7 expression was not significantly different in all groups.

CONCLUSION

Cinnamaldehyde, acting with TMZ, reduces glioma cell viability possibly via decreasing CXCR4 expression.

Evolutionary engineering and molecular characterization of a caffeine-resistant Saccharomyces cerevisiae strain

Caffeine is a naturally occurring alkaloid, where its major consumption occurs with beverages such as coffee, soft drinks and tea. Despite a variety of reports on the effects of caffeine on diverse organisms including yeast, the complex molecular basis of caffeine resistance and response has yet to be understood. In this study, a caffeine-hyperresistant and genetically stable Saccharomyces cerevisiae mutant was obtained for the first time by evolutionary engineering, using batch selection in the presence of gradually increased caffeine stress levels and without any mutagenesis of the initial population prior to selection. The selected mutant could resist up to 50 mM caffeine, a level, to our knowledge, that has not been reported for S. cerevisiae so far. The mutant was also resistant to the cell wall-damaging agent lyticase, and it showed cross-resistance against various compounds such as rapamycin, antimycin, coniferyl aldehyde and cycloheximide. Comparative transcriptomic analysis results revealed that the genes involved in the energy conservation and production pathways, and pleiotropic drug resistance were overexpressed. Whole genome re-sequencing identified single nucleotide polymorphisms in only three genes of the caffeine-hyperresistant mutant; PDR1, PDR5 and RIM8, which may play a potential role in caffeine-hyperresistance.

Methylxanthines: Potential Therapeutic Agents for Glioblastoma

Glioblastoma (GBM) is the most common and aggressive primary brain tumor. Currently, treatment is ineffective and the median overall survival is 20.9 months. The poor prognosis of GBM is a consequence of several altered signaling pathways that favor the proliferation and survival of neoplastic cells. One of these pathways is the deregulation of phosphodiesterases (PDEs). These enzymes participate in the development of GBM and may have value as therapeutic targets to treat GBM. Methylxanthines (MXTs) such as caffeine, theophylline, and theobromine are PDE inhibitors and constitute a promising therapeutic anti-cancer agent against GBM. MTXs also regulate various cell processes such as proliferation, migration, cell death, and differentiation; these processes are related to cancer progression, making MXTs potential therapeutic agents in GBM.