Effects of difference in self-esteem between spouses on depressive symptom: Result from a data nationally representative of South Korean

Although there are many studies on self-esteem, no study has analyzed the relationship between depressive symptom and difference in self-esteem between spouses. We aimed to determine how differences in self-esteem between spouses are associated with depressive symptoms. We used data collected from 2011 to 2013 by the Korean Welfare Panel Study. The initial 2011 baseline data included 3257 married couples over 25 years of age. We used linear mixed-effects models, accounting for the longitudinal nature of the data, to analyze the associations between the self-esteem of spouses and CESD-11 scores. About 20% of the respondents had different self-esteem with their intimate partners. Individuals with spouses having lower self-esteem than self significantly higher depression scores. Individuals with spouses having higher self-esteem than self had significantly lower depression scores regardless of sex. Our findings show how different self-esteem with their intimate partners could be associated with depressive symptoms and imply that one's self-esteem could affect the mental health of one's partner. Therefore, we should give more attention to self-esteem, which can affect families and society.

MRI audit of complications in intracranial stenosis treated with Wingspan device

OBJECTIVES

To evaluate the safety and efficacy of the Wingspan device for the treatment of symptomatic intracranial atherosclerotic stenosis (ICAS).

METHODS

We audited a prospective ongoing database of consecutive patients who received Wingspan stenting between January 2013 and December 2015. All patients underwent MRI to audit any complications during the early follow-up period. We focused on the clinical demographics, lesion characteristics, treatment results, and periprocedural complications. Functional outcomes were measured with the modified Rankin Scale (mRS) at discharge and after 3 months.

RESULTS

Intracranial stenting was performed in 50 patients (100%). Mean stenosis pre-stenting was 76.5±13.1% and post-stenting residual stenosis was 19.8±13.8%. The overall 30-day rate of procedure-related complications was 6.0% (3/50). Two patients (4%) developed in-stent restenosis, one of whom had a dissection at the middle cerebral artery. Interestingly, on the follow-up MRI scan there was a high incidence of asymptomatic diffusion-weighted imaging (DWI) hyperintensities, 46% (23/50) presumed to be due to microembolic causes. At the 90-day, 180-day, and 1-year follow-up, three patients had further strokes resulting in a total complication rate of 12%. 92% had excellent outcomes (mRS 0-1) and only one patient had deterioration of his mRS score.

CONCLUSIONS

ICAS treated by Wingspan stenting using pre-placement balloon angioplasty appears safe and effective with a high technical success rate and favorable outcomes. There is a high incidence of asymptomatic DWI hyperintensites post-procedure, but these do not appear to result in long-term sequelae.

The impact of shift and night work on health related quality of life of working women: findings from the Korea Health Panel

Background

Night and shift work status has been associated with health related quality of life (HRQoL) in economically active women. This study aimed to investigate the association between night or shift work status and HRQoL of economically active women and to further analyze how marital status interplays in the objected relationship.

Methods

Data were from the Korea Health Panel, 2011 to 2013. A total of 2238 working women were included for analysis. Work status was categorized into day work, night work, and rotating shift work and its association with HRQoL, measured using the EuroQol-5D (EQ-5D) index, was investigated using the generalized estimating equation (GEE) model.

Results

Compared to the day work reference group, the night work group (β: −0.9757, P = 0.0202) and the rotating shift work group (β: −0.7947, P = 0.0363) showed decreases in EQ-5D scores. This trend was maintained regardless of marital status, although decreases in health related quality of life were particularly pronounced among night shift workers with a spouse.

Conclusion

Night and rotating shift work status was associated with HRQoL of economically active women as individuals working night and rotating shifts showed decreases in EQ-5D scores compared to individuals working day shifts. The findings of this study signify the importance of monitoring the HRQoL status of women working night and rotating shifts as these individuals may be comparatively vulnerable to reduced HRQoL.

Effect of Socioeconomic Status on the Linkage Between Suicidal Ideation and Suicide Attempts

Previous suicide attempts are a leading risk factor for completed suicide. To identify specific characteristics of those at high risk for attempts, we investigated associations with socioeconomic status (SES). Data from the 2013 Korean Community Health Survey (KCHS) included adults who reported suicidal ideation (N = 220,245). Attempts in the past 12 months were assessed. Associations of demographic, socioeconomic, and suicide-related behavioral factors were analyzed using multiple logistic regression. Among those with suicidal ideation, 862 (3.9%) had attempted suicide. After stratification by age and gender, results showed that low education and unemployed young adult men and women had significantly higher rates of attempts. The lowest income level was associated with significantly higher rates of attempts in only young adult women. Among those with the lowest and highest income, the association between ideation and attempts was attenuated, whereas it was enhanced among other income groups.

Depressive symptoms of house-poor persons: Korean panel data evidence

BACKGROUND

There are no studies researching the relationship between house-poor persons and mental health. Therefore, this study aimed to investigate the relationship between house-poor status and depressive symptoms.

AIM

To examine the relationship between the house-poor and depressive symptoms according to household income.

METHODS

Data from the Korean Welfare Panel Study were used. House-poor were defined as people having possession with over 10% house-related interest in disposable income. About 7,565 participants over the age of 19 years were followed up from 2011 to 2013. The generalized estimating equations were used for analysis.

RESULTS

Individuals with more house-related debt showed increasingly higher depression scores (possession with under 5% related debt to disposable income β = 0.2024, p = .1544; under 10% β = 0.7030, p = .0008; over 10% β = 1.3207, p < .0001). Individuals possessing houses with over 10% ratio of house-related debts to disposable income had higher depression scores than individuals without house ownership (no possession β = 0.8927, p < .0001).

CONCLUSION

Individuals without houses and individuals owning houses with higher percentages of house-related interests showed higher levels of depressive symptoms. Therefore, this study affirmed that the importance of considering the most vulnerable groups in addressing the mental health of individual.

Modification of cysteine 457 in plakoglobin modulates the proliferation and migration of colorectal cancer cells by altering binding to E-cadherin/catenins

OBJECTIVES

In tissue samples from patients with colorectal cancer (CRC), oxidation of C420 and C457 of plakoglobin (Pg) within tumor tissue was identified by proteomic analysis. The aim of this study was to identify the roles of Pg C420 and C457.

METHODS

Human CRC tissues, CRC and breast cancer cells, and normal mouse colon were prepared to validate Pg oxidation. MC38 cells were co-transfected with E-cadherin plus wild type (WT) or mutant (C420S or C457S) Pg to evaluate protein interactions and cellular localization, proliferation, and migration.

RESULTS

Pg was more oxidized in stage III CRC tumor tissue than in non-tumor tissue. Similar oxidation of Pg was elicited by H₂O₂ treatment in normal colon and cancer cells. C457S Pg exhibited diminished binding to E-cadherin and α-catenin, and reduced the assembly of E-cadherin-α-/β-catenin complexes. Correspondingly, immunofluorescent analysis of Pg cellular localization suggested impaired binding of C457S Pg to membranes. Cell migration and proliferation were also suppressed in C457S-expressing cells.

DISCUSSION

Pg appears to be redox-sensitive in cancer, and the C457 modification may impair cell migration and proliferation by affecting its interaction with the E-cadherin/catenin axis. Our findings suggest that redox-sensitive cysteines of Pg may be the targets for CRC therapy.

Effect of working hours and precarious employment on depressive symptoms in South Korean employees: a longitudinal study

OBJECTIVES

Long working hours and precarious employment are relatively common in South Korea. Since both can impact on mental health, this study examined their independent and combined effects on depressive symptoms of employees.

METHODS

Data were from the Korean Welfare Panel Study (KOWEPS), 2010-2013. A total of 2733 full-time employees without depressive symptoms were analysed. Hierarchical logistic regression models were used to investigate the effect of the number of working hours per week (eg, 35-40 hours, 41-52 hours, 53-68 hours, and >68 hours) and employment status (permanent vs precarious employment) on depressive symptoms, measured using the Center for Epidemiological Studies Depression (CES-D) 11 scale.

RESULTS

Compared with individuals working 35-40 hours/week, employees working above 68 hours (OR 1.57, 95% CI 1.05 to 2.34) had higher odds of depressive symptoms after full adjustment. Similarly, precarious employees (OR 1.34, 95% CI 1.02 to 1.75) showed worse mental health than permanent employees. In the combined effect model, employees in precarious employment who worked above 68 hours/week (OR, 2.03 95% CI 1.08 to 3.83) exhibited the highest odds of depressive symptoms compared with permanent employees working 35 to 40 hours/week.

CONCLUSIONS

Long work hours and precarious employment status were associated with higher odds of depressive symptoms. The findings highlight the importance of monitoring and addressing the vulnerable groups of employees to reduce the mental health burden of economically active individuals.

Salvia plebeia R.Br. inhibits signal transduction of IL-6 and prevents ovariectomy-induced bone loss by suppressing osteoclastogenesis

The interleukin-6 (IL-6) family of cytokines plays a key role in the pathogenesis of rheumatoid arthritis and osteoporosis through the regulation of bone formation and resorption. In this study, it was observed that ethanol extract of Salvia plebeia R.Br. (S.P-EE) inhibited IL-6-induced signaling cascade including phosphorylation of JAK2/STAT3 and ERK. Subsequently, it was examined whether S.P-EE treatment could recover bone loss in ovariectomized (OVX) mice. Indeed, S.P-EE exhibited both preventive and therapeutic effect on OVX-induced bone loss in trabecular microarchitecture along with significant increase in bone mineral density and content. To understand the mechanism of action of S.P-EE in bone metabolism, the effect of S.P-EE on osteoclast differentiation and activity was investigated. S.P-EE significantly inhibited RANKL-induced osteoclast differentiation by suppressing phosphorylation of MAPK and Akt, and expression of NFATc1 and osteoclast marker genes. S.P-EE also inhibited bone-resorbing activity of osteoclasts. Furthermore, isolation and identification of the active compounds which are responsible for the inhibitory effect of S.P-EE on osteoclast differentiation was carried out. Six major flavonoids and plebeiolide A-C were isolated and examined their effects on osteoclast differentiation. Luteolin and hispidulin, and plebeiolide A and C, not B exhibited potent inhibitory activity on RANKL-induced osteoclast formation.

The effect of childhood and current economic status on depressive symptoms in South Korean individuals: a longitudinal study

BACKGROUND

Mental health inequality along the economic strata is prominent in South Korea, particularly as intergenerational material transfer is becoming increasingly important in gaining economic status. Therefore, this study aimed to investigate the relationship between current and childhood economic status and depressive symptoms in adults aged 20 or above.

METHODS

This study used data from the Korean Welfare Panel Study (KOWEPS), 2010 to 2013. A total of 9,645 individuals aged 20 years or above without depressive symptoms in 2010 were analyzed. The effect of childhood and current economic status, categorized into low, middle, and high groups, on depressive symptoms was investigated using hierarchical logistic regression models. Depressive symptoms were measured using the Center for Epidemiological Studies Depression (CES-D 11) scale. Subgroup analysis was performed based on education level.

RESULTS

Compared to the middle current-middle childhood economic status group, the low-low group (OR: 1.88, CI: 1.61-2.20), low-middle group (OR: 1.68, CI: 1.43-1.98), and low-high group (OR: 1.64, CI: 1.34-2.01) were more likely to have depressive symptoms. The high-low group (OR: 0.68, CI: 0.55-0.84), high-middle group (OR: 0.67, CI: 0.56-0.81), and high-high group (OR: 0.45, CI: 0.27-0.75) were less likely to have depressive symptoms. This trend was generally maintained with regard to education level, but the effects were not statistically significant in the high current economic status groups among participants with a university degree or above.

CONCLUSION

Low current economic status was associated with a higher likelihood of depressive symptoms. In particular, the low current-low childhood economic status group showed the highest likelihood of depressive symptoms, suggesting the adverse mental health effects of prolonged poverty. Therefore, the findings reveal that mental health inequalities are present along the economic strata and require proper addressing of the mental health of lower income individuals.

Depressive symptoms in spouse caregivers of dementia patients: A longitudinal study in South Korea

AIM

To investigate the association between spouse cognitive status and depressive symptoms in cohabiting spouses, and to further analyze how participation in social network-enhancing activities interplays in the objected relationship.

METHODS

Data from the Korean Longitudinal Study of Aging, 2006-2012, were used. A total of 2782 male and 2515 female married participants currently cohabiting with their partners were included in the baseline. The association between spouse cognitive status and depressive symptoms, measured using the Center for Epidemiological Studies Depression scale, was investigated through the generalized estimating equation model.

RESULTS

When setting the participants living with spouses of normal cognitive function as reference, participants living with spouses having mild dementia (male β 0.7349, P ≤ 0.0001; female β 0.8042, P ≤ 0.0001), and moderate and severe dementia (male β 1.1504, P ≤ 0.0001; female β 1.2462, P ≤ 0.0006) showed higher depression scores in a dose-response relationship. Additionally, male and female subjects participating in social network facilitating activities had lower increases in depression scores than their non-participating counterparts.

CONCLUSIONS

Spouse cognitive impairment is associated with increasing depression scores in cohabiting caregivers. Individuals not participating in social network-facilitating activities are more vulnerable to the negative mental health effects of spouse cognitive impairment. Hence, considering the increasing importance of late life depression and cognitive decline in aging societies, it is important to note the protective effects of social network and support in addressing the mental health of spouse caregivers. Geriatr Gerontol Int 2017; 17: 973-983.

Disparities in the experience and treatment of dental caries among children aged 9-18 years: the cross-sectional study of Korean National Health and Nutrition Examination Survey (2012-2013)

BACKGROUND

The aim of this study is to examine the association between parental socioeconomic status (SES) and the experience as well as treatment of dental caries among children aged 9 to 18 years.

METHODS

Data from 1253 children aged 9-18 years from the Korean National Health and Nutrition Examination Survey (2012-2013) were analyzed. Parental socioeconomic status was measured using household income level and maternal educational level. The decayed, missing, and filled teeth (DMFT) index was used to measure experience of dental caries (DMFT ≥ 1). Non-treatment of dental caries was measured according to whether the participants who experienced dental caries used a dental service at a dental clinic to treat caries during the previous year. Logistic regression was used to investigate the association between parental socioeconomic status and the experience of dental caries as well as the association between parental socioeconomic status and the non-treatment of dental caries among children that have experienced caries.

RESULTS

A total of 808 subjects (64.5 %) experienced dental caries among 1253 participants, and 582 of these 808 subjects (72.0 %) did not receive treatment among those having experience of dental caries. Parental socioeconomic status was not associated with experience of dental caries. However, those from low- and middle-income households were less likely to receive treatment than those from high-income households (odds ratio [OR] 2.11 [95 % confidence interval (CI) 1.16-3.86], OR 2.14 [95 % CI 1.27-3.62]). In particular, those from low- and middle-income households who had regular dental checkups were more likely to have untreated caries than those from high-income households (OR 3.58 [95 % CI 1.25-10.24]).

CONCLUSIONS

This study demonstrates the parental household income-related disparities in children's dental health treatment. Efforts should be made to lower financial barriers to dental health services, particularly among those from low-income households, in order to reduce dental health disparities in the treatment of caries in children.

The impact of occupation according to income on depressive symptoms in South Korean individuals: Findings from the Korean Welfare Panel Study

BACKGROUND

In South Korea, societal perceptions on occupation are distinct, with people favouring white collar jobs. Hence both occupation type and income can have mental health effects.

AIM

To examine the relationship between occupational classification and depression, along with the combined effect of occupational classification and household income.

METHODS

Data were from the Korean Welfare Panel Study (KOWEPS), 2010-2013. A total of 4,694 economically active participants at baseline were followed. Association between occupational classification and depression, measured using the Center for Epidemiological Studies Depression (CES-D) scale 11, was investigated using the linear mixed effects model.

RESULTS

Blue collar (β: 0.3871, p = .0109) and sales and service worker groups (β: 0.3418, p = .0307) showed higher depression scores than the white collar group. Compared to the white collar high-income group, white collar low income, blue collar middle income, blue collar middle-low income, blue collar low income, sales and service middle-high income, sales and service middle-low income and sales and service low-income groups had higher depression scores.

CONCLUSION

Occupational classification is associated with increasing depression scores. Excluding the highest income group, blue collar and sales and service worker groups exhibit higher depression scores than their white collar counterparts, implying the importance of addressing these groups.

NOX1/2 activation in human gingival fibroblasts by Fusobacterium nucleatum facilitates attachment of Porphyromonas gingivalis

Periodontal diseases are infectious polymicrobial inflammatory diseases that lead to destruction of the periodontal ligament, gingiva, and alveolar bone. Sequential colonization of a broad range of bacteria, including Fusobacterium nucleatum and Porphyromonas gingivalis, is an important phenomenon in this disease model. F. nucleatum is a facultative anaerobic species thought to be a key mediator of dental plaque maturation due to its extensive coaggregation with other oral bacteria, while P. gingivalis is an obligate anaerobic species that induces gingival inflammation by secreting various virulence factors. The formation of a bacterial complex by these two species is central to the pathogenesis of periodontal disease. Reactive oxygen species (ROS) are produced during bacterial infections and are involved in intracellular signaling. However, the impact of oral bacteria-induced ROS on the ecology of F. nucleatum and P. gingivalis has yet to be clarified. In the present study, we investigated ROS production induced in primary human oral cells by F. nucleatum and P. gingivalis and its effect on the formation of their bacterial complexes and further host cell apoptosis. We found that in primary human gingival fibroblasts (GFs), two NADPH oxidase isoforms, NOX1 and NOX2, were activated in response to F. nucleatum infection but not P. gingivalis infection. Accordingly, increased NADPH oxidase activity and production of superoxide anion were observed in GFs after F. nucleatum infection, but not after P. gingivalis infection. Interestingly, in NOX1, NOX2, or NOX1/NOX2 knockdown cells, the number of P. gingivalis decreased when the cells were coinfected with F. nucleatum. A similar pattern of host cell apoptosis was observed. This implies that F. nucleatum contributes to attachment of P. gingivalis by triggering activation of NADPH oxidase in host cells, which may provide an environment more favorable to strict anaerobic bacteria and have a subsequent effect on apoptosis of host cells.

Association between weight control failure and suicidal ideation in overweight and obese adults: a cross-sectional study

Background

Korea has the highest suicide rate in the OECD and is one of the few OECD countries whose suicide rates have not decreased in recent years. To address these issues, we investigated the effects of weight control failure on suicidal ideation in the overweight and obese populations.

Methods

We performed a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey (2008–2012) consisting of 6621 individuals 40 years of age or older. Logistic regression analysis was used to identify the relationship between weight control failure and suicidal ideation in the overweight and obese populations.

Results

A total of 6621 participants were analyzed in this study (overweight group: 2439; obese group: 4182). Among them, weight control failure (weight gain with weight loss efforts) was experienced in 962 obese (males 16.3 %, females 29.6 %) and 412 overweight individuals (males 9.1 %, females 23.4 %). Weight control failure was significantly associated with suicidal ideation in obese females (OR = 1.70, 95 % CI 1.21–2.39), but this association was not significant in obese males or in either sex of the overweight group.

Conclusions

Findings from this study suggest that weight control failure is associated with an increased risk of suicidal ideation among obese women. Furthermore, intervention programs that aim to address the prevalence of suicide, especially for obese women, are needed.

Impact of adenotonsillectomy on nocturnal enuresis in children with sleep-disordered breathing: A prospective study

OBJECTIVES/HYPOTHESIS

To investigate the relationship between sleep-disordered breathing (SDB) and nocturnal enuresis (NE) in children and to prospectively evaluate the effectiveness of adenotonsillectomy on resolving enuresis in indicated SDB patients with NE.

METHODS

We prospectively collected data from 183 children (121 males, mean age 8.17 ± 2.84 years) who underwent adenotonsillectomy to treat SDB between July 2011 and July 2013, and analyzed the prevalence of NE. Before and 3 months after surgery, all parents were requested to answer a self-reported SDB scale questionnaire (22 questions, 0-22 points) and a NE questionnaire (episodes of enuresis per month). Paired t test, Student t test, and Chi-square test were used to analyze the data.

RESULTS

Overall prevalence of NE was 9.3% (17 patients) preoperatively and 1.5% postoperatively (four patients). After adenotonsillectomy, prevalence of NE and the mean SDB scale were significantly decreased (both P values < 0.001). After adenotonsillectomy, 13 of the 17 NE patients (76.5%) showed complete resolution. There was significantly higher prevalence of NE in patients with obstructive sleep apnea (OSA) than those without OSA (13.1%, 14 of 107 vs. 3.9%, 3 of 76; P = 0.036).

CONCLUSION

There is strong association between NE and SDB, and adenotonsillectomy can markedly improve enuresis in the majority of children with NE and SDB.

LEVELS OF EVIDENCE

4. Laryngoscope, 126:1241-1245, 2016.

Antioxidant enzymes as redox-based biomarkers: a brief review

The field of redox proteomics focuses to a large extent on analyzing cysteine oxidation in proteins under different experimental conditions and states of diseases. The identification and localization of oxidized cysteines within the cellular milieu is critical for understanding the redox regulation of proteins under physiological and pathophysiological conditions, and it will in turn provide important information that are potentially useful for the development of novel strategies in the treatment and prevention of diseases associated with oxidative stress. Antioxidant enzymes that catalyze oxidation/reduction processes are able to serve as redox biomarkers in various human diseases, and they are key regulators controlling the redox state of functional proteins. Redox regulators with antioxidant properties related to active mediators, cellular organelles, and the surrounding environments are all connected within a network and are involved in diseases related to redox imbalance including cancer, ischemia/reperfusion injury, neurodegenerative diseases, as well as normal aging. In this review, we will briefly look at the selected aspects of oxidative thiol modification in antioxidant enzymes and thiol oxidation in proteins affected by redox control of antioxidant enzymes and their relation to disease. [BMB Reports 2015; 48(4): 200-208]

Differential expression of immunologic proteins in gingiva after socket preservation in mini pigs

During healing following tooth extraction, inflammation and the immune response within the extraction socket are related to bone resorption.

Comparative Study for Efficacy and Safety of Adenoidectomy according to the Surgical Method: A Prospective Multicenter Study

Background/Objective

There have been several operative techniques for adenoidectomy and their efficacy and morbidity are different according to the technique. This prospective multicenter study was aimed to compare the efficacy and morbidity of coblation adenoidectomy (CA) with those of power-assisted adenoidectomy.

Study Design

Prospective multi-institutional study.

Methods

Children who underwent CA, power-assisted adenoidectomy with cauterization (PAA+C) or without cauterization (PAA-C) due to adenoid hypertrophy were enrolled from 13 hospitals between July 2013 and June 2014. Mean operation time, degree of intraoperative bleeding and postoperative bleeding rate were evaluated.

Results

A total of 388 children (mean age ± standard deviation = 6.6 ± 2.5 years; 245 males and 143 females) were included. According to the adenoidectomy technique, the children were classified into 3 groups: (1) CA (n = 116); (2) PAA+C (n = 153); and (3) PAA-C (n = 119). Significant differences were not found in age and sex among three groups. In the CA group, mean operation time was significantly shorter (P < 0.001) and degree of intraoperative bleeding was significantly less (P < 0.001) compared to PAA+C or PAA-C group. Delayed postoperative bleeding rate of PAA-C group was significantly higher than that of CA or PAA+C group (P = 0.016).

Conclusions

This prospective multicenter study showed that CA was superior to PAA in terms of mean operation time and degree of intraoperative bleeding.

Novel Radiolytic Rotenone Derivative, Rotenoisin B with Potent Anti-Carcinogenic Activity in Hepatic Cancer Cells

Rotenone, isolated from roots of derris plant, has been shown to possess various biological activities, which lead to attempting to develop a potent drug against several diseases. However, recent studies have demonstrated that rotenone has the potential to induce several adverse effects such as a neurodegenerative disease. Radiolytic transformation of the rotenone with gamma-irradiation created a new product, named rotenoisin B. The present work was designed to investigate the anticancer activity of rotenoisin B with low toxicity and its molecular mechanism in hepatic cancer cells compared to a parent compound, rotenone. Our results showed rotenoisin B inhibited hepatic cancer cells’ proliferation in a dose dependent manner and increased in apoptotic cells. Interestingly, rotenoisin B showed low toxic effects on normal cells compared to rotenone. Mitochondrial transmembrane potential has been decreased, which leads to cytochrome c release. Down regulation of anti-apoptotic Bcl-2 levels as well as the up regulation of proapoptotic Bax levels were observed. The cleaved PARP (poly ADP-ribose polymerase) level increased as well. Moreover, phosphorylation of extracellular signal regulated kinase (ERK) and p38 slightly up regulated and intracellular reactive oxygen species (ROS) increased as well as cell cycle arrest predominantly at the G₂/M phase observed. These results suggest that rotenoisin B might be a potent anticancer candidate similar to rotenone in hepatic cancer cells with low toxicity to normal cells even at high concentrations compared to rotenone.

Role of transcription factor Sp1 in the 4-O-methylhonokiol-mediated apoptotic effect on oral squamous cancer cells and xenograft

Recently, biphenolic components derived from the Magnolia family have been studied for anti-cancer, anti-stress, and anti-inflammatory pharmacological effects. However, the pharmacological mechanism of action of 4-O-methylhonokiol (MH) is not clear in oral cancer. The aim of this study was to investigate the role of MH in apoptosis and its molecular mechanism in oral squamous cell carcinoma (OSCC) cell lines, HN22 and HSC4, as well as tumor xenografts. Here, we demonstrated that MH decreased cell growth and induced apoptosis in HN22 and HSC4 cells through the regulation of specificity protein 1 (Sp1). We employed several experimental techniques such as MTS assay, DAPI staining, PI staining, Annexin-V/7-ADD staining, RT-PCR, western blot analysis, immunocytochemistry, immunohistochemistry, TUNEL assay and in vivo xenograft model analysis. MH inhibited Sp1 protein expression and reduced Sp1 protein levels via both proteasome-dependent protein degradation and inhibition of protein synthesis in HN22 and HSC4 cells; MH did not alter Sp1 mRNA levels. We found that MH directly binds Sp1 by Sepharose 4B pull-down assay and molecular modeling. In addition, treatment with MH or knocking down Sp1 expression suppressed oral cancer cell colony formation. Moreover, MH treatment effectively inhibited tumor growth and Sp1 levels in BALB/c nude mice bearing HN22 cell xenografts. These results indicated that MH inhibited cell growth, colony formation and also induced apoptosis via Sp1 suppression in OSCC cells and xenograft tumors. Thus, MH is a potent anti-cancer drug candidate for oral cancer.