PKR-Mediated Phosphorylation of eIF2a and CHK1 Is Associated with Doxorubicin-Mediated Apoptosis in HCC1143 Triple-Negative Breast Cancer Cells.

Triple-negative breast cancer is more aggressive than other types of breast cancer. Protein kinase R (PKR), which is activated by dsRNA, is known to play a role in doxorubicin-mediated apoptosis; however, its role in DNA damage-mediated apoptosis is not well understood. In this study, we investigated the roles of PKR and its downstream players in doxorubicin-treated HCC1143 triple-negative breast cancer cells. Doxorubicin treatment induces DNA damage and apoptosis. Interestingly, doxorubicin treatment induced the phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α) via PKR, whereas the inhibition of PKR with inhibitor C16 reduced eIF2α phosphorylation. Under these conditions, doxorubicin-mediated DNA fragmentation, cell death, and poly(ADP ribose) polymerase and caspase 7 levels were recovered. In addition, phosphorylation of checkpoint kinase 1 (CHK1), which is known to be involved in doxorubicin-mediated DNA damage, was increased by doxorubicin treatment, but blocked by PKR inhibition. Protein translation was downregulated by doxorubicin treatment and upregulated by blocking PKR phosphorylation. These results suggest that PKR activation induces apoptosis by increasing the phosphorylation of eIF2α and CHK1 and decreasing the global protein translation in doxorubicin-treated HCC1143 triple-negative breast cancer cells.

Activation of ERK and p38 Reduces AZD8055-Mediated Inhibition of Protein Synthesis in Hepatocellular Carcinoma HepG2 Cell Line.

Protein synthesis is important for maintaining cellular homeostasis under various stress responses. In this study, we screened an anticancer drug library to select compounds with translational repression functions. AZD8055, an ATP-competitive mechanistic target of rapamycin complex 1/2 (mTORC1/2) inhibitor, was selected as a translational suppressor. AZD8055 inhibited protein synthesis in mouse embryonic fibroblasts and hepatocellular carcinoma HepG2 cells. Extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) were activated during the early phase of mTORC1/2 inhibition by AZD8055 treatment. Combined treatment of AZD8055 with the MAPK kinase1/2 (MEK1/2) inhibitor refametinib or the p38 inhibitor SB203580 markedly decreased translation in HepG2 cells. Thus, the inhibition of ERK1/2 or p38 may enhance the efficacy of AZD8055-mediated inhibition of protein synthesis. In addition, AZD8055 down-regulated the phosphorylation of eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), and AZD8055-induced phosphorylation of ERK1/2 and p38 had no effect on phosphorylation status of 4E-BP1. Interestingly, AZD8055 modulated the 4E-BP1 mRNA pool by up-regulating ERK1/2 and p38 pathways. Together, these results suggest that AZD8055-induced activation of MAPKs interferes with inhibition of protein synthesis at an early stage of mTORC1/2 inhibition, and that it may contribute to the development of resistance to mTORC1/2 inhibitors.

Benign childhood epilepsy with centrotemporal spikes: to treat or not to treat.

BACKGROUND AND PURPOSE: The aim of this study was to evaluate the benefits and risks of oxcarbazepine (OXC) monotherapy in children with newly diagnosed, benign partial epilepsy based on clinico-electrical and neuropsychological evaluation over time. METHODS: The study was open label, prospective, multicenter based. A total of 39 children with BRE were involved in the study. They were randomized into two groups (T; treatment with OXC, NT; No treatment) to compare the effectiveness of OXC treatment. All children underwent EEGs with quantification and a comprehensive battery of neuropsychological tests at the first visit and follow up visit at 6 months. RESULTS: The subjects made a slight progress in general intelligence measures over time in both groups (95.4±10.5 to 97.6±7.5 for T, 107.6±17.3 to 111.4±18.6 for NT). Memory and frontal executive functions did not change over time in both groups in terms of the memory quotient (MQ) (106.7±27.5 to 103.4± 19.3 for T, 105.8±13.2 to 104.9±17.2 for NT) and executive intelligence quotient (EIQ) (114.7±18.3 to 108.9±12.5 for T, 100.6±25.1 to 101.2±13.9 for NT). However, when sub-domain scores were compared between the two groups, the treatment group got significantly worse over time in the verbal fluency test (11.5±3.8 to 8.0±1.4 for T, 10.3±3.9 to 11.5±2.1 for NT; p<0.05) and level 1 of Stroop test (9.3±3.0 to 7.5±1.3 for T, 11.0±3.7 to 11.2±2.6 for NT; p<0.05). The subjects might have cognitive and behavioral difficulties in association with frontal lobe dysfunctions, but these difficulties did not seem to be dependent on the number of seizures, the abundance of subclinical epileptiform discharges, or the anti-epileptic treatment. CONCLUSIONS: We think that OXC monotherapy is effective for children with BRE, but is to be given to the selected patients such as patients with prolonged or frequent seizures. However, further studies are needed to have a better understanding in this matter.

Cognitive and other neuropsychological profiles in children with newly diagnosed benign rolandic epilepsy.

PURPOSE: Although benign rolandic epilepsy (BRE) is a benign condition, it may be associated with a spectrum of behavioral, psychiatric, and cognitive disorders. This study aimed to assess the cognitive and other neuropsychological profiles of children with BRE. METHODS: In total, 23 children with BRE were consecutively recruited. All children underwent sleep electroencephalography (EEG) and were assessed on a battery of comprehensive neuropsychological tests including the Korean versions of the Wechsler intelligence scale for children III, frontal executive neuropsychological test, rey complex figure test, Wisconsin card sorting test, attention deficit diagnostic scale, and child behavior checklist scale. RESULTS: The study subjects included 13 boys and 10 girls aged 9.0±1.6 years. Our subjects showed an average monthly seizure frequency of 0.9±0.7, and a majority of them had focal seizures (70%). The spike index (frequency/min) was 4.1±5.3 (right) and 13.1±15.9 (left). Of the 23 subjects, 9 showed frequent spikes (>10/min) on the EEG. The subjects had normal cognitive and frontal executive functions, memory, and other neuropsychological sub-domain scores, even though 8 children (35%) showed some evidence of learning difficulties, attention deficits, and aggressive behavior. CONCLUSION: Our data have limited predictive value; however, these data demonstrate that although BRE appears to be benign at the onset, children with BRE might develop cognitive, behavioral, and other psychiatric disorders during the active phase of epilepsy, and these problems may even outlast the BRE. Therefore, we recommend scrupulous follow-up for children with BRE.

Clinical spectrum and prognostic factors of acute necrotizing encephalopathy in children.

This study was conducted to investigate the etiology, the clinical characteristics and prognosis of acute necrotizing encephalopathy (ANE) in Korean children. Six children (1 yr to 7 yr) patients with ANE were enrolled. They were diagnosed by clinical and radiological characteristics and their clinical data were retrospectively analyzed. In a search of clinically plausible causes, brain MRI in all patients, mitochondrial DNA studies for mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) and myoclonus epilepsy and ragged red fibers (MERRF) in four patients, and genomic typing on HLA DRB/HLA DQB genes in three patients were performed. All had precedent illnesses and the main initial symptoms included mental change (83%), seizures (50%), and focal deficits (50%). MRI revealed increased T2 signal density in the bilateral thalami and/or the brainstem in all patients. Mitochodrial DNA studies for MELAS and MERRF were negative in those children and HLA-DRB1*1401, HLA-DRB3*0202, and HLA-DQB1*0502 seemed to be significant. A high dose steroid was given to all patients, which seemed to be partly effective except for 2 patients. In conclusion, ANE is relatively rare, but can result in serious neurological complication in children. Early detection and appropriate treatment may lead to a better neurological outcome.

Long-term effectiveness and tolerability of topiramate in children with epilepsy under the age of 2 years: 4-year follow-up.

This is a long-term, open label, observational study aimed to broaden our clinical experiences in managing infants and toddlers with epilepsy. The long-term retention rate and side effects of topiramate (TPM) in them were evaluated and compared with carbamazepine (CBZ). A total of 146 children were involved in the study (TPM=41, CBZ=105). The retention rates at 24 , 36, and 48 months were 46.3%, 34.1%, 26.8% for TPM and 36.2%, 23.8%, 13.3% for CBZ, respectively. At 6 months after starting antiepileptic drugs (AED), the seizure freedom or clinical efficacy (seizure reduction rate more than 50 percent) were 73.2% for TPM and 62.9% for CBZ. The major side effects led to discontinuation included psychomotor slowing, poor oral intake from TPM and sleepiness and skin rash from CBZ. TPM was discontinued due to side effects in one case (2.4%) and lack of efficacy in five cases (12.2%), whereas CBZ was discontinued due to lack of efficacy (22.9%) and side effects (6.7%). As compared with CBZ, TPM showed the same long-term retention rate in children under the age of 2 yr, and no serious side effects. It is therefore concluded that TPM can be considered as a major AED for treating children with epilepsy under the age of 2 yr.