[Overexpression of NAT10 induced platinum drugs resistance in breast cancer cell].

Objective: To observe the platinum drugs resistance effect of N-acetyltransferase 10 (NAT10) overexpression in breast cancer cell line and elucidate the underlining mechanisms. Methods: The experiment was divided into wild-type (MCF-7 wild-type cells without any treatment) group, NAT10 overexpression group (H-NAT10 plasmid transfected into MCF-7 cells) and NAT10 knockdown group (SH-NAT10 plasmid transfected into MCF-7 cells). The invasion was detected by Transwell array, the interaction between NAT10 and PARP1 was detected by co-immunoprecipitation. The impact of NAT10 overexpression or knockdown on the acetylation level of PARP1 and its half-life was also determined. Immunostaining and IP array were used to detect the recruitment of DNA damage repair protein by acetylated PARP1. Flow cytometry was used to detect the cell apoptosis. Results: Transwell invasion assay showed that the number of cell invasion was 483.00±46.90 in the NAT10 overexpression group, 469.00±40.50 in the NAT10 knockdown group, and 445.00±35.50 in the MCF-7 wild-type cells, and the differences were not statistically significant (P>0.05). In the presence of 10 µmol/L oxaliplatin, the number of cell invasion was 502.00±45.60 in the NAT10 overexpression group and 105.00±20.50 in the NAT10 knockdown group, both statistically significant (P<0.05) compared with 219.00±31.50 in wild-type cells. In the presence of 10 µmol/L oxaliplatin, NAT10 overexpression enhanced the binding of PARP1 to NAT10 compared with wild-type cells, whereas the use of the NAT10 inhibitor Remodelin inhibited the mutual binding of the two. Overexpression of NAT10 induced PARP1 acetylation followed by increased PARP1 binding to XRCC1, and knockdown of NAT10 expression reduced PARP1 binding to XRCC1. Overexpression of NAT10 enhanced PARP1 binding to LIG3, while knockdown of NAT10 expression decreased PARP1 binding to LIG3. In 10 µmol/L oxaliplatin-treated cells, the γH2AX expression level was 0.38±0.02 in NAT10 overexpressing cells and 1.36±0.15 in NAT10 knockdown cells, both statistically significant (P<0.05) compared with 1.00±0.00 in wild-type cells. In 10 µmol/L oxaliplatin treated cells, the apoptosis rate was (6.54±0.68)% in the NAT10 overexpression group and (12.98±2.54)% in the NAT10 knockdown group, both of which were statistically significant (P<0.05) compared with (9.67±0.37)% in wild-type cells. Conclusion: NAT10 overexpression enhances the binding of NAT10 to PARP1 and promotes the acetylation of PARP1, which in turn prolongs the half-life of PARP1, thus enhancing PARP1 recruitment of DNA damage repair related proteins to the damage sites, promoting DNA damage repair and ultimately the survival of breast cancer cells.

Aberrant GATA2 epigenetic dysregulation induces a GATA2/GATA6 switch in human gastric cancer.

Six GATA transcription factors play important roles in eukaryotic development. Among these, GATA2, an essential factor for the hematopoietic cell lineage, exhibits low expression in human gastric tissues, whereas GATA6, which is crucial for gastrointestinal development and differentiation, is frequently amplified and/or overexpressed in human gastric cancer. Interestingly, we found that GATA6 was overexpressed in human gastric cancer cells only when GATA2 expression was completely absent, thereby showing an inverse correlation between GATA2 and GATA6. In gastric cancer cells that express high GATA6 levels, a GATA2 CpG island is hypermethylated, repressing expression in these cells. In contrast, GATA6 expression is undetectable in GATA2-overexpressing gastric cancer cells, which lack GATA2 DNA methylation. Furthermore, PRC2 complex-mediated transcriptional silencing of GATA6 was observed in the GATA2-overexpressing cells. We also show that the GATA2 and PRC2 complexes are enriched within the GATA6 locus, and that the recruitment of the PRC2 complex is impaired by disrupting GATA2 expression, resulting in GATA6 upregulation. In addition, ectopic GATA2 expression significantly downregulates GATA6 expression, suggesting GATA2 directly represses GATA6. Furthermore, GATA6 downregulation showed antitumor activity by inducing growth arrest. Finally, we show that aberrant GATA2 methylation occurs early during the multistep process of gastric carcinogenesis regardless of Helicobacter pylori infection. Taken together, GATA2 dysregulation by epigenetic modification is associated with unfavorable phenotypes in human gastric cancer cells by allowing GATA6 expression.

Is intraoperative neurophysiological monitoring valuable predicting postoperative neurological recovery?

OBJECTIVES: We investigated the ability of intraoperative neurophysiological monitoring to predict postoperative neurological recovery in intradural-extramedullary spinal cord tumors. METHODS: From 2010 to 2014, we operated on 173 intradural-extramedullary spinal cord tumor patients with intraoperative neurophysiological monitoring. We retrospectively compared preoperative and postoperative clinical status using a modified McCormick grading scale and correlated with intraoperative neurophysiological monitoring. We followed patients for at least 1 year and correlated neurological outcomes with intraoperative changes in intraoperative neurophysiological monitoring. We then compared the degree of intraoperative neurophysiological monitoring change with the duration of the neurological deficit. RESULTS: Monitorability was 92% and 57% with transcranial motor-evoked potential and somatosensory-evoked potential modalities, respectively. Waveform attenuation on transcranial motor-evoked potentials was detected in 8.17% of cases. For somatosensory-evoked potentials, waveform attenuation was detected in 7% of the patients. A multimodality approach incorporating any transcranial motor-evoked potential changes had a sensitivity of 0.91 and a specificity of 0.98. The McCormick grade scale increased until 1 month in patients with alarm criteria on transcranial motor-evoked potentials (P<0.05). CONCLUSIONS: Patients suffered neurological deterioration in case of abolishment or >50% irreversible attenuation of the waveform in transcranial motor-evoked potentials. All patients gradually recovered after 1 postoperative month with alarm criteria from 50% to 80% irreversible amplitude drop on transcranial motor-evoked potentials.

Variability of neural activation during walking in humans: short heels and big calves.

People come in different shapes and sizes. In particular, calf muscle size in humans varies considerably. One possible cause for the different shapes of calf muscles is the inherent difference in neural signals sent to these muscles during walking. In sedentary adults, the variability in neural control of the calf muscles was examined with muscle size, walking kinematics and limb morphometrics. Half the subjects walked while activating their medial gastrocnemius (MG) muscles more strongly than their lateral gastrocnemius (LG) muscles during most walking speeds ('MG-biased'). The other subjects walked while activating their MG and LG muscles nearly equally ('unbiased'). Those who walked with an MG-biased recruitment pattern also had thicker MG muscles and shorter heel lengths, or MG muscle moment arms, than unbiased walkers, but were similar in height, weight, lower limb length, foot length, and exhibited similar walking kinematics. The relatively less plastic skeletal system may drive calf muscle size and motor recruitment patterns of walking in humans.

Effects of cloned-cattle meat on reproductive physiology in rats.

The influence of the cloned-cattle meat diets upon reproduction in mammals was rarely studied. This study was performed to analyze the effects of the diets containing cloned-cattle (Korean native beef, Hanwoo) meat on the reproductive physiology in rats. The male and female rats were fed with the diets containing 5% or 10% of normal- (N-5 or N-10) or cloned- (C-5 or C-10) cattle meat during test periods. The rats fed with commercial pellets were used as control. Lower food consumption in normal- and cloned-cattle meat diet groups is detected in both male and female rats compared with that of control (P < 0.05, 0.01 and 0.001). No signs of cloned-cattle meat diets on male reproductive parameters are found in all groups, except for lower sperm deformity in C-5 group (P < 0.05) and higher testosterone concentration in C-10 group (P < 0.05), respectively. There are no significant test substance-related differences of Caesarean section and delivery in dams and external examination and physiological development test in neonate compared with control and normal meat groups. Based on these results, it can be postulated that there are no obvious negative effects on the reproductive physiology in rats fed with cloned-cattle meat diets compared to their comparators.

Application of ICHD-II criteria for headaches in a TMJ and orofacial pain clinic.

The aim of this study was to identify and diagnose headache in a temporomandibular joint and orofacial pain clinic population using the second edition of The International Classification of Headache Disorder criteria. In 502 temporomandibular disorder and orofacial pain patients, 246 patients (49%) were diagnosed with tension-type headache (TTH), followed by migraine without aura (14.5%), probable migraine (12.9%), migraine with aura (7%), probable TTH (4.8%) and cluster headache (0.2%). The prevalence of headaches was compared between male and female patients, and the prevalence of migraine was found to be higher in women than in men. In evaluating by age, the prevalence of migraine was highest in patients in their 20s and 30s and declined as age increased above 40. TTH showed the highest rate throughout all age groups, but it also decreased as age increased. In this study, the prevalence of migraine was lower than that reported in Dr Kim et al.'s study, and the prevalence of TTH much higher than that reported in the previous study. Of the headache patients, 81.1% presented with masseter muscle pain and 47.8% with temporal muscle pain. This finding suggests that pericranial muscle pain may be an inducing factor of primary headache.

Combined motor- and somatosensory-evoked potential monitoring for spine and spinal cord surgery: correlation of clinical and neurophysiological data in 85 consecutive procedures.

STUDY DESIGN: Prospective study. OBJECTIVES: The primary objective of neurophysiological monitoring during surgery is to prevent permanent neurological sequelae. To avoid neurological injury, we applied somatosensory-evoked potentials (SEPs) and/or motor-evoked potentials (MEPs). We evaluated whether the combination of SEP and MEP for spinal surgery may be beneficial. SETTING: Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea. METHODS: Combined SEP/MEP monitoring was attempted in 100 consecutive procedures for spinal operations. Trains of transcranial electrical stimulation over the motor cortex were used to elicit MEPs from the muscles of the upper/lower limbs. The tibial and median nerves were stimulated to record SEP. RESULTS: Combined SEP/MEP recording was successfully achieved in 85 of 100 operations. In 61 of 85 operations (71%), SEP and MEP were stable, and all patients remained neurologically intact after surgery. Significant MEP changes were recorded in 20 operations, either combined with (n=4) or without (n=16) SEP changes. In 7 of these 20 operations, MEP recovered to some extent after surgical intervention, and these patients showed no neurological changes. In the remaining 13 operations, MEP did not recover and the patients had a transient (n=4) or a permanent (n=3) motor deficit. Significant SEP changes with stable MEP were observed in four operations, all of which were not related to postoperative motor deficit. CONCLUSION: Combined SEP/MEP monitoring provided higher sensitivity and higher positive/negative predictive value than single-modality monitoring techniques. Detection of MEP changes and adjustment of surgical strategy may prevent irreversible pyramidal tract damage.

Acute ophthalmoplegia (without ataxia) associated with anti-GQ1b antibody.

BACKGROUND: Anti-GQ1b antibody has been found in Miller Fisher syndrome (MFS), Guillain-Barré syndrome (GBS) with ophthalmoplegia, Bickerstaff brainstem encephalitis (BBE), and acute ophthalmoplegia without ataxia (AO). The aim of this study was to determine the clinical features of AO associated with anti-GQ1b antibody. METHODS: We retrospectively collected 34 patients with anti-GQ1b antibody syndrome. Of these patients, 31 patients had ophthalmoplegia. The patients with ophthalmoplegia were classified into MFS (n = 13), AO (n = 11), GBS with ophthalmoplegia (n = 6), and BBE (n = 1). We analyzed clinical features and patterns of external and internal ophthalmoplegia of AO, and neuro-ophthalmologic findings were compared with those of other anti-GQ1b syndromes with ophthalmoplegia. RESULTS: AO was observed in 11 (32.4%) of the 34 patients with anti-GQ1b antibody. External ophthalmoparesis was present in all the patients and included mixed horizontal-vertical (n = 7), pure horizontal (n = 3), and pure vertical gaze palsy (n = 1). Binocular involvement was common, but unilateral ophthalmoparesis was also observed in 27.3%. Other findings included ptosis (n = 5, 45.5%) and internal ophthalmoplegia (n = 6, 54.5%). Other anti-GQ1b antibody syndromes had prominent neurologic signs including ataxia, weakness, and facial palsy in addition to ophthalmoplegia. The patterns of neuro-ophthalmologic findings did not differ between AO and other anti-GQ1b antibody syndromes with ophthalmoplegia. CONCLUSIONS: Acute ophthalmoplegia (AO) commonly occurs in anti-GQ1b antibody syndrome and manifests as various combinations of external and internal ophthalmoplegia. Internal ophthalmoplegia is fairly common and unilateral involvement may occur in AO.

Histone deacetylase inhibitor apicidin downregulates DNA methyltransferase 1 expression and induces repressive histone modifications via recruitment of corepressor complex to promoter region in human cervix cancer cells.

Dysregulation of DNA methyltransferase (DNMT)1 expression is associated with cellular transformation, and inhibition of DNMT1 exerts antitumorigenic effects. Here, we report that DNMT1 abnormally expressed in HeLa cells is downregulated by a histone deacetylase (HDAC) inhibitor apicidin, which is correlated with induction of repressive histone modifications on the promoter site. Apicidin selectively represses the expression of DNMT1 among DNMTs in HeLa cells, independent of cell cycle arrest at G0/G1. Furthermore, apicidin causes a significant reduction in the recruitment of RNA polymerase II into the promoter. Chromatin immunoprecipitation analysis shows that even though apicidin causes global hyperacetylation of histone H3 and H4, localized deacetylation of histone H3 and H4 occurs at the E2F binding site, which is accompanied by the recruitment of pRB and the replacement of P/CAF with HDAC1 into the sites. In addition, K4-trimethylated H3 on nucleosomes associated with the transcriptional start site is depleted following apicidin treatment, whereas repressive markers, K9- and K27-trimethylation of H3 are enriched on the site. The downregulation of DNMT1 expression seems to require de novo protein synthesis, because the apicidin effect is antagonized by cycloheximide treatment. Moreover, knock down of DNMT1 with siRNA induces the apoptosis of HeLa cells, indicating that downregulation of DNMT1 might be a good strategy for therapeutics of human cervix cancer. Collectively, our findings will provide a mechanistic rationale for the use of HDAC inhibitors in cancer therapeutics.

Activation of NF-kappaB by HDAC inhibitor apicidin through Sp1-dependent de novo protein synthesis: its implication for resistance to apoptosis.

Histone deacetylase (HDAC) inhibitors are promising anti-cancer drugs, but these exert differential responses depending on the cell types. Here, we demonstrate a new mechanism for activation of nuclear factor-kappaB (NF-kappaB) by HDAC inhibitor apicidin and the role of NF-kappaB signaling pathway for mediating differential cellular responses, especially, apoptosis. Treatment of HeLa cells with apicidin increases transcriptional activity of NF-kappaB and its target gene IL-8 and cIAP-1 induction, which involves the activation of IKK-IkappaBalpha signaling pathway through Sp1-dependent de novo protein synthesis. In parallel, apicidin treatment leads to histone hyperacetylation in the IL-8 promoter region independent of NF-kappaB signaling pathway, which is not sufficient for full transcription of IL-8 gene. This NF-kappaB activation contributes to resistance of HeLa cells to apoptotic potential of apicidin. Collectively, our results suggest that activation of NF-kappaB signaling cascade functions as a critical modulator to determine cell fate on apoptosis in response to HDAC inhibitors.

Merlin facilitates ubiquitination and degradation of transactivation-responsive RNA-binding protein.

The Nf2 tumor suppressor codes for merlin, a protein whose function is largely unknown. We have previously demonstrated a novel interaction between merlin and TRBP, which inhibits the oncogenic activity of TRBP. In spite of the significance of their functional interaction, its molecular mechanism still remains to be elucidated. In this report, we investigated how merlin inhibits the oncogenic activity of TRBP in association with cell growth conditions. In the human embryonic kidney 293 cell line, the level of endogenous merlin increased, whereas that of endogenous TRBP significantly decreased along with the increase in cell confluence. We demonstrated that the carboxyl-terminal region of TRBP was responsible for this phenomenon using stable cell lines expressing deletion mutants of TRBP. The overexpression of merlin decreased the protein level of TRBP, and the ubiquitin-like subdomain of merlin's FERM domain was important for this activity. We also demonstrated that TRBP is ubiquitinylated and the ubiquitinylated forms of TRBP are accumulated by ectopically expressed merlin or cell confluence in the presence of MG132, a proteasome inhibitor. Furthermore, we showed that the regulation of TRBP in response to cell confluence was abolished upon knockdown of merlin expression by specific small interfering RNA. Finally, we showed that ectopically expressed merlin restored cell-cell contact inhibition in cells stably expressing TRBP but not in TRBPDeltac. These results suggest that merlin is involved in the regulation of TRBP protein level by facilitating its ubiquitination in response to such cues as cell-cell contacts.

Antioxidative effects of 7-hydroxy-3-methoxy-cadalene extracted from Zelkova serrata on 4-(methylinitros amino)-1-(3-pyridyl)-1-butanone-induced oxidative stress in A/J mice.

Effects of 7-hydroxy-3-methoxy-cadalene (cadalene) extracted from Zelkova serrata on 4-(methylinitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced oxidative stress were examined using A/J mice. NNK (65 microg/ml water) was orally administered to 20 mice for 7 weeks, followed by free feeding of a commercial diet, not containing cadalene, for 2 weeks. The control group was maintained without NNK and cadalene administration, and treatment groups with NNK and cadalene (6.25, 25, 100 mg/kg feed) feeding for 25 weeks. The glutathione concentration of cadalene-treated (65 microg/ml water) group was significantly higher than that of the group treated only with NNK (p < 0.05). The results of our study strongly indicate that cadalene exerts antioxidative effect on NNK-induced lung tumorigenesis in A/J mice.

Vim thalamotomy for Holmes' tremor secondary to midbrain tumour.

Holmes' (rubral or midbrain) tremor is an unusual combination of 2 Hz to 5 Hz rest, postural, and kinetic tremors of an upper extremity. This tremor has been considered to result from the lesions in the vicinity of the red nucleus in the midbrain. There has been no systematic analysis of the surgical target in the Holmes' tremor so far of nucleus ventrointermedius (Vim) or globus pallidus interna. This 26 year old man gradually developed a disabling midbrain tremor involving both the distal and proximal parts of the left upper arm. Additional neurological findings included oculomotor palsy and ataxia of the left arm. On the radiological studies, a mass lesion (germinoma) was found on the midbrain tegmentum, which was treated by conventional radiation therapy. Although there was improvement in the radiological imaging, his midbrain tremor became intolerable despite medical treatment. The authors performed MR guided stereotactic Vim thalamotomy. With radiofrequency lesioning in the right Vim, his resting, postural, and action tremors were much alleviated in both the distal and proximal parts of the left upper extremity. The authors consider that Vim thalamotomy is still an effective means of controlling midbrain tremors involving the proximal upper limb.

Significance of temperature difference between cerebral cortex and axilla in patients under hypothermia management.

It is believed that the brain temperature is about 1 degree C higher than the other peripheral temperature. But the result has been mostly obtained in normothermia patients. The objective of this study was to evaluate whether the brain temperature is still higher than the axillary one in the hypothermia patients. Sixty-three patients who underwent craniotomy with implantation of the thermal diffusion thermometer were included in this study. Fifty-four patients were in normothermia and nine patients were managed with mild to moderate hypothermia (about 32 degrees C). The temperature of the cerebral cortex and axilla was measured simultaneously every 2 hours. 1900 paired sample data were collected and analyzed. The temperature difference between the cerebral cortex and the axilla was 1.04 +/- 0.67 degrees C in normothermia patients and 0.91 +/- 0.84 degree C in hypothermic patients. The temperature difference has no statistical significance between the two groups (unpaired t-test, P > 0.05). Our results demonstrate that the brain temperature in the patients under hypothermia management appears to be still about 1 degree C higher than the axilla throughout the study period almost in the same fashion as in normothermia patients.

Low-frequency collective chain dynamics in a model biomembrane.

Proton NMR was employed as a probe for the collective hydrocarbon chain dynamics in decylammonium chloride (C10H21NH3Cl), a model biomembrane undergoing an irreversible structural phase transition sequence. Our rotating frame spin-lattice relaxation measurements revealed a low-frequency critical collective chain dynamics in the kHz regime, which is associated with the interdigitated to noninterdigitated chain configurational phase transition.