Carbamazepine, a Histone Deacetylase Inhibitor Induces Apoptosis in Human Colon Adenocarcinoma Cell Line HT-29

Cilostazol geno-protective effects mitigate carbamazepine-induced genotoxicity in human cultured blood lymphocytes

Background

Carbamazepine is one of the most widely used antiepileptic drugs. Carbamazepine has been shown to be toxic to cells. Cilostazol, an antiplatelet agent, has known antioxidant, antiproliferative, anti-inflammatory, and anti-tumor effects.

Objective

This study aimed to explore whether carbamazepine and cilostazol exert genotoxic and/or cytotoxic effects in human cultured blood lymphocytes and the impact of combining both drugs on such effects.

Methods

Genotoxicity was examined using sister chromatid exchange (SCE) assay, while cytotoxicity was evaluated by cell kinetic assays (mitotic and proliferative indices).

Results

Study findings have revealed that carbamazepine markedly increased SCEs (p<0.01), while cilostazol significantly decreased their frequencies (p<0.01). In addition, the frequency of SCEs of the combination of both drugs was similar to that of the control group (p>0.05). Carbamazepine increased the cell proliferative index (p<0.01) while cilostazol decreased it (p<0.01). The proliferative index was normalized to the control level when both drugs were combined.

Conclusion

We suggest that cilostazol has the potential to protect human lymphocytes from carbamazepine-induced toxic effects.

Effects of Mixtures of Emerging Pollutants and Drugs on Modulation of Biomarkers Related to Toxicity, Oxidative Stress, and Cancer

Background/Objectives: Over time, the scientific community has developed a growing interest in the effects of mixtures of different compounds, for which there is currently no established evidence or knowledge, in relation to certain categories of xenobiotics. It is well known that exposure to pollutants causes oxidative stress, resulting in the overproduction of reactive oxygen species (ROS), which can affect signaling pathways that regulate the cell cycle, apoptosis, energy balance, and cellular metabolism. The aim of this study was to investigate the effects of sub-lethal concentrations of mixtures of emerging pollutants and pharmaceuticals on the modulation of biomarkers related to toxicity, oxidative stress, and cancer. Methods: In this study, the hepatoma cell line HepG2 was exposed to increasing concentrations of polybrominated diphenyl ether 47 (BDE-47), cadmium chloride (CdCl2), and carbamazepine (CBZ), both individually and in mixtures, for 72 h to assess cytotoxicity using the MTT assay. The subsequent step, following the identification of the sub-lethal concentration, was to investigate the effects of exposure at the gene expression level, through the evaluation of molecular markers related to cell cycle and apoptosis (p53), oxidative stress (NRF2), conjugation and detoxification of xenobiotics (CYP2C9 and GST), DNA damage (RAD51 and γH2AFX), and SUMOylation processes (SUMO1 and UBC9) in order to identify any potential alterations in pathways that are normally activated at the cellular level. Results: The results showed that contaminants tend to affect the enzymatic detoxification and antioxidant system, influencing DNA repair defense mechanisms involved in resistance to oxidative stress. The combined effect of the compounds at sub-lethal doses results in a greater activation of these pathways compared to exposure to each compound alone, thereby exacerbating their cytotoxicity. Conclusions: The biomarkers analyzed could contribute to the definition of early warning markers useful for environmental monitoring, while simultaneously providing insight into the toxicity and hazard levels of these substances in the environment and associated health risks.

Eslicarbazepine induces apoptosis and cell cycle arrest in C6 glioma cells in vitro and suppresses tumor growth in an intracranial rat model

BACKGROUND

Glioblastoma multiforme (GBM) is the most malignant brain tumor, with a poor prognosis and life expectancy of 14-16 months after diagnosis. The standard treatment for GBM consists of surgery, radiotherapy, and chemotherapy with temozolomide. Most patients become resistant to treatment after some time, and the tumor recurs. Therefore, there is a need for new drugs to manage GBM. Eslicarbazepine (ESL) is a well-known antiepileptic drug belonging to the dibenzazepine group with anticancer potentials. In this study, for the first time, we evaluated the potential effects of ESL on C6 cell growth, both in vitro and in vivo, and examined its molecular effects.

METHODS

To determine the effect of ESL on the c6 cell line, cell viability, proliferation, and migration were evaluated by MTT assay, colony formation, and wound healing assay. Also, apoptosis and cell cycle were examined by flow cytometry, qRT-PCR, and western blotting. In addition, an intracranial model in Wistar rats was used to investigate the effect of ESL in vivo, and the tumor size was measured using both Caliper and MRI.

RESULTS

The obtained results are extremely consistent and highly encouraging. C6 cell viability, proliferation, and migration were significantly suppressed in ESL-treated C6 cells (p < 0.001), as determined by cell-based assays. ESL treatment led to significant enhancement of apoptosis (p < 0.01), as determined by flow cytometry, and upregulation of genes involved in cell apoptosis, such as the Bax/Bcl2 ratio at RNA (p < 0.05) and protein levels (5.37-fold). Flow cytometric analysis of ESL-treated cells revealed G2/M phase cell cycle arrest. ESL-treated cells demonstrated 2.49-fold upregulation of p21 alongside, 0.22-fold downregulation of cyclin B1, and 0.34-fold downregulation of cyclin-dependent kinase-1 at the protein level. Administration of ESL (30 mg/kg) to male rats bearing C6 intracranial tumors also suppressed the tumor volume and weight (p < 0.01).

CONCLUSIONS

Based on these novel findings, ESL has the potential for further experimental and clinical studies in glioblastoma.

Sesamol induces cytotoxicity via mitochondrial apoptosis in SCC-25 cells

Sesamol is the main constituent of sesame seed oil and is obtained from Sesamum indicum. Oral squamous cell carcinoma (OSCC) is one of the most common neoplasms affecting the oral cavity. In this study, we investigated the cytotoxic potentials of sesamol on human oral squamous carcinoma (SCC-25) cells. Human oral squamous carcinoma cells were treated with different concentrations (62.5, 125, and 250 μM/mL) of sesamol for 24 h. Cytotoxicity was analyzed by 3- (4, 5- dimethylthiazol -2- yl) -2, 5-diphenyltetrazolium bromide (MTT) assay. Intracellular reactive oxygen species (ROS) expression was investigated by dichloro-dihydro-fluorescein diacetate assay. Apoptosis-related morphology was analyzed by acridine orange/ethidium bromide staining. Caspase-9 expression was analyzed by confocal microscopic double immunofluorescence staining. Mitochondrial apoptosis-related markers are analyzed using qPCR. Sesamol treatment caused a significant cytotoxic effect in OSCC cells. Sesamol-induced cytotoxic effect was associated with intracellular ROS generation. Sesamol treatments induced a significant increase in the early and late apoptotic cells. This treatment also induced caspase-9 expression in OSCC cells. Sesamol treatments caused downregulation of Harvey rat sarcoma viral oncogene homolog (HRAS) expression at protein and gene levels. Sesamol treatment modulates intrinsic apoptotic marker gene expression in OSCC cells. Overall results confirm the anti-cancer potential of sesamol and it seems to be a promising candidate for OSCC.

Sodium Valproate, a Histone Deacetylase Inhibitor, Provokes Reactive Oxygen Species-Mediated Cytotoxicity in Human Hepatocellular Carcinoma Cells

BACKGROUND AND AIM

Sodium valproate (SV), a novel class of histone deacetylases (HDACs) inhibitors commonly used as an antiepileptic drug. HDAC inhibitors are known to possess anticancer potentials. In this study, we investigated the cytotoxic potential of SV in human hepatocellular carcinoma (HepG2 cells) cell line.

METHODS

MTT assay was used to analyze cytotoxicity. Intracellular ROS and cytochrome c expression were analyzed by fluorescence microscopy. Morphology-related apoptosis was analyzed by dual staining with acridine orange/ethidium bromide. Caspase 3 protein expression was investigated by Western blotting analysis.

RESULTS

Sodium valproate treatments in HepG2 cells caused significant and dose-dependent cytotoxicity. Intracellular ROS was remarkably increased in the cells which are treated with SV and caused early and late apoptosis as evidenced by dual staining. SV-treated cells expressed cytochrome c and caspase 3 protein expression.

CONCLUSION

These results suggest the cytotoxic potentials of SV in HepG2 cells. This study may give an important clue for the inclusion of SV as an adjuvant along with standard anticancer agents after necessary in vivo and clinical studies.

NBM-BMX, an HDAC8 Inhibitor, Overcomes Temozolomide Resistance in Glioblastoma Multiforme by Downregulating the β-Catenin/c-Myc/SOX2 Pathway and Upregulating p53-Mediated MGMT Inhibition

Although histone deacetylase 8 (HDAC8) plays a role in glioblastoma multiforme (GBM), whether its inhibition facilitates the treatment of temozolomide (TMZ)-resistant GBM (GBM-R) remains unclear. By assessing the gene expression profiles from short hairpin RNA of HDAC8 in the new version of Connectivity Map (CLUE) and cells treated by NBM-BMX (BMX)-, an HDAC8 inhibitor, data analysis reveals that the Wnt signaling pathway and apoptosis might be the underlying mechanisms in BMX-elicited treatment. This study evaluated the efficacy of cotreatment with BMX and TMZ in GBM-R cells. We observed that cotreatment with BMX and TMZ could overcome resistance in GBM-R cells and inhibit cell viability, markedly inhibit cell proliferation, and then induce cell cycle arrest and apoptosis. In addition, the expression level of β-catenin was reversed by proteasome inhibitor via the β-catenin/ GSK3β signaling pathway to reduce the expression level of c-Myc and cyclin D1 in GBM-R cells. BMX and TMZ cotreatment also upregulated WT-p53 mediated MGMT inhibition, thereby triggering the activation of caspase-3 and eventually leading to apoptosis in GBM-R cells. Moreover, BMX and TMZ attenuated the expression of CD133, CD44, and SOX2 in GBM-R cells. In conclusion, BMX overcomes TMZ resistance by enhancing TMZ-mediated cytotoxic effect by downregulating the β-catenin/c-Myc/SOX2 signaling pathway and upregulating WT-p53 mediated MGMT inhibition. These findings indicate a promising drug combination for precision personal treating of TMZ-resistant WT-p53 GBM cells.

Carbamazepine at environmentally relevant concentrations caused DNA damage and apoptosis in the liver of Chinese rare minnows (Gobiocypris rarus) by the Ras/Raf/ERK/p53 signaling pathway

To assess genetoxicity and the underlying mechanisms of carbamazepine (CBZ) toxicity in fish, adult Chinese rare minnows (Gobiocypris rarus) were exposed to 1, 10, and 100 μg/L CBZ for 28 d. Comet assays indicated that hepatic DNA damage was significantly increased in groups of minnows exposed to CBZ at all concentrations in a dose-dependent manner compared to those of the control groups (p < 0.05). Liver levels of 8-hydroxydeoxyguanosine (8-OHdG) were significantly increased at 10 and 100 μg/L CBZ (p < 0.05). TUNEL assays indicated that the average apoptotic rates of the livers of female and male minnows were significantly increased following exposure to CBZ at all concentrations for 28 d (p < 0.05). Significant increases in caspase 3 and 9 activities after CBZ exposure at all concentrations and caspase 8 at 10 and 100 μg/L CBZ exposure reflected the presence of mitochondrial apoptosis (p < 0.05). The mRNA levels of gadd45a, mdm2, casp3 and casp9 in female and male minnows exposed to CBZ at all concentrations were significantly increased compared with those in the control groups (p < 0.05). Significant increases in the levels of p21 in female minnows exposed to 1 and 100 μg/L CBZ, p53 in female minnows at all CBZ treatments and bcl2 in male minnows exposed to 1 and 100 μg/L CBZ were observed, indicating p53 pathway activation. The inhibition of ras levels in females and males exposed to CBZ at all concentrations and increased levels of raf1 in males exposed to CBZ at all concentrations indicated Ras/Raf1/MAPK (ERK) activation. Therefore, the present study demonstrates that CBZ at environmentally relevant levels induces DNA damage and apoptosis in Chinese rare minnows by the Ras/Raf/ERK/p53 signaling pathway.

Reactive Oxygen Species-Mediated Mitochondrial Dysfunction Triggers Sodium Valproate-Induced Cytotoxicity in Human Colorectal Adenocarcinoma Cells

BACKGROUND

Colorectal cancer (CRC) is one of the frequently diagnosed cancers worldwide. Currently used chemotherapeutic drugs have several side effects. Histone deacetylase (HDAC) enzyme inhibitors possess potential anti-cancer effects. Therefore, we investigated the cytotoxic potential of sodium valproate, a HDAC inhibitor in human colorectal adenocarcinoma (HT-29) cells.

METHODS

MTT assay was used to analyze the cytotoxicity of HT-29 cells. Intracellular reactive oxygen species (ROS) induction was evaluated by dichloro-dihydro-fluorescein diacetate staining. Dual staining with acridine orange/ethidium bromide was used to investigate the morphology-related apoptotic cell death. Mitochondrial membrane potential was analyzed by rhodamine 123 staining. E-cadherin protein expression was examined by immunofluorescence staining.

RESULTS

Sodium valproate at 2 and 4 mM/mL treatments significantly induced cytotoxicity. Increased intracellular ROS expression was observed in the cells treated with sodium valproate. This treatment also induced mitochondrial dissipation, apoptosis-related morphological damage, and E-cadherin expression in HT-29 cells.

CONCLUSIONS

Our present results suggest that sodium valproate is cytotoxic to HT-29 cells due to its pro-oxidative and apoptosis inducing potential. Sodium valproate can be used as an adjuvant along with standard chemotherapeutic agents in CRC patients after necessary in vivo and clinical studies.