Crosstalk between WNT and STAT3 is mediated by galectin-3 in tumor progression.

BACKGROUND: Aberrant activation of the WNT/ß-catenin and STAT3 signaling pathways plays a critical role in cancer progression. However, direct targeting of these pathways as an anti-cancer therapeutic approach needs to be reconsidered due to its serious side effects. Here, we demonstrate that overexpression of WNT induces STAT3 activation in a galectin-3-dependent manner. METHODS: We investigated how galectin-3 mediates the crosstalk between WNT/ß-catenin and STAT3 signaling and whether inhibition of galectin-3 can reduce gastric cancer. The molecular mechanisms were analyzed by biochemical assays using cultured gastric cancer cells, patient tissues, and genetically engineered mice. Moreover, we confirm of therapeutic effects of GB1107, a cell-penetrating galectin-3 specific inhibitor, using orthotopic gastric cancer-bearing mice RESULTS: Increased levels of galectin-3 and STAT3 phosphorylation were detected in the stomach tissues of WNT1-overexpressing mouse models. Also, high expression levels and co-localization of ß-catenin, pSTAT3, and galectin-3 in patients with advanced gastric cancer were correlated with a poorer prognosis. Galectin-3 depletion significantly decreased STAT3 Tyr705 phosphorylation, which regulates its nuclear localization and transcriptional activation. A peptide of galectin-3 (Y45-Q48) directly bound to the STAT3 SH2 domain and enhanced its phosphorylation. GB1107, a specific membrane-penetrating inhibitor of galectin-3, significantly reduced the activation of both STAT3 and ß-catenin and inhibited tumor growth in orthotopic gastric cancer-bearing mice. CONCLUSIONS: We propose that galectin-3 mediates the crosstalk between the WNT and STAT3 signaling pathways. Therefore GB1107, a galectin-3-specific inhibitor, maybe a potent agent with anti-gastric cancer activity. Further studies are needed for its clinical application in gastric cancer therapy.

Upregulation of LAMB1 via ERK/c-Jun Axis Promotes Gastric Cancer Growth and Motility.

Gastric cancer is the fifth most common cancer worldwide with a poor survival rate. Therefore, it is important to identify predictive and prognostic biomarkers of gastric cancer. Laminin subunit beta 1 (LAMB1) is involved in attachment, migration, and organization during development, and its elevated expression has been associated with several cancers. However, the role and mechanism of LAMB1 in gastric cancer remains unknown. Here, we determined that LAMB1 is upregulated in gastric cancer tissues and contributes to cell growth and motility. Using a public database, we showed that LAMB1 expression was significantly upregulated in gastric cancer compared to normal tissues. LAMB1 was also found to be associated with poor prognosis in patients with gastric cancer. Overexpression of LAMB1 elevated cell proliferation, invasion, and migration; however, knockdown of LAMB1 decreased these effects in gastric cancer cells. U0126, an extracellular signal-regulated kinase (ERK) inhibitor, regulated the expression of LAMB1 in gastric cancer cells. Additionally, we showed that c-Jun directly binds to the LAMB1 promoter as a transcription factor and regulates its gene expression via the ERK pathway in gastric cancer cells. Therefore, our study indicates that LAMB1 promotes cell growth and motility via the ERK/c-Jun axis and is a potential biomarker and therapeutic target of gastric cancer.

Reversible SUMOylation of TBL1-TBLR1 regulates ß-catenin-mediated Wnt signaling.

Dysregulation of Wnt signaling has been implicated in tumorigenesis. The role of Transducin ß-like proteins TBL1-TBLR1 in the promotion of Wnt/ß-catenin-mediated oncogenesis has recently been emphasized; however, the molecular basis of activation of Wnt signaling by the corepressor TBL1-TBLR1 is incompletely understood. Here, we show that both TBL1 and TBLR1 are SUMOylated in a Wnt signaling-dependent manner, and that this modification is selectively reversed by SUMO-specific protease I (SENP1). SUMOylation dismissed TBL1-TBLR1 from the nuclear hormone receptor corepressor (NCoR) complex, increased recruitment of the TBL1-TBLR1-ß-catenin complex to the promoter of Wnt target genes, and consequently led to activation of Wnt signaling. Conversely, SENP1 decreased formation of the TBL1-TBLR1-ß-catenin complex, leading to inhibition of ß-catenin-mediated transcription. Importantly, inhibition of SUMOylation significantly decreased the tumorigenicity of SW480 colon cancer cells. Thus, our data reveal a mechanism for activation of Wnt signaling via the SUMOylation-dependent disassembly of the corepressor complex.

Predicting and Overcoming Chemotherapeutic Resistance in Breast Cancer.

Our understanding of breast cancer and its therapeutic approach has improved greatly due to the advancement of molecular biology in recent years. Clinically, breast cancers are characterized into three basic types based on their immunohistochemical properties. They are triple-negative breast cancer, estrogen receptor (ER) and progesterone receptor (PR)-positive-HR positive breast cancer, and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Even though these subtypes have been characterized, assessment of a breast cancer's receptor status is still widely used to determine whether or not a targeted therapy could be applied. Moreover, drug resistance is common in all breast cancer types despite the different treatment modalities applied. The development of resistance to different therapeutics is not mutually exclusive. It seems that tumor could be resistant to multiple treatment strategies, such as being both chemoresistant and monoclonal antibody resistant. However, the underlying mechanisms are complicated and need further investigation. In this chapter, we aim to provide a brief review of the different types of breast cancer and their respective treatment strategies. We also review the possible mechanisms of potential drug resistance associated with each treatment type. We believe that a better understanding of the drug resistance mechanisms can lead to a more effective and efficient therapeutic success.

Glucose deprivation triggers protein kinase C-dependent ß-catenin proteasomal degradation.

Autophagy is a conserved process that contributes to cell homeostasis. It is well known that induction mainly occurs in response to nutrient starvation, such as starvation of amino acids and insulin, and its mechanisms have been extensively characterized. However, the mechanisms behind cellular glucose deprivation-induced autophagy are as of now poorly understood. In the present study, we determined a mechanism by which glucose deprivation induced the PKC-dependent proteasomal degradation of ß-catenin, leading to autophagy. Glucose deprivation was shown to cause a sub-G1 transition and enhancement of the LC3-II protein levels, whereas ß-catenin protein underwent degradation in a proteasome-dependent manner. Moreover, the inhibition of GSK3ß was unable to abolish the glucose deprivation-mediated ß-catenin degradation or up-regulation of LC3-II protein levels, which suggested GSK3ß-independent protein degradation. Intriguingly, the inhibition of PKCα using a pharmacological inhibitor and transfection of siRNA for PKCα was observed to effectively block glucose deprivation-induced ß-catenin degradation as well as the increase in LC3-II levels and the accumulation of a sub-G1 population. Together, our results demonstrated a molecular mechanism by which glucose deprivation can induce the GSK3ß-independent protein degradation of ß-catenin, leading to autophagy.

Roles of Protein Post-Translational Modifications During Adipocyte Senescence.

Adipocytes are adipose tissues that supply energy to the body through lipids. The two main types of adipocytes comprise white adipocytes (WAT) that store energy, and brown adipocytes (BAT), which generate heat by burning stored fat (thermogenesis). Emerging evidence indicates that dysregulated adipocyte senescence may disrupt metabolic homeostasis, leading to various diseases and aging. Adipocytes undergo senescence via irreversible cell-cycle arrest in response to DNA damage, oxidative stress, telomere dysfunction, or adipocyte over-expansion upon chronic lipid accumulation. The amount of detectable BAT decreases with age. Activation of cell cycle regulators and dysregulation of adipogenesis-regulating factors may constitute a molecular mechanism that accelerates adipocyte senescence. To better understand the regulation of adipocyte senescence, the effects of post-translational modifications (PTMs), is essential for clarifying the activity and stability of these proteins. PTMs are covalent enzymatic protein modifications introduced following protein biosynthesis, such as phosphorylation, acetylation, ubiquitination, or glycosylation. Determining the contribution of PTMs to adipocyte senescence may identify new therapeutic targets for the regulation of adipocyte senescence. In this review, we discuss a conceptual case in which PTMs regulate adipocyte senescence and explain the mechanisms underlying protein regulation, which may lead to the development of effective strategies to combat metabolic diseases.

Deubiquitinase USP1 enhances CCAAT/enhancer-binding protein beta (C/EBPß) stability and accelerates adipogenesis and lipid accumulation.

Dysregulation of the ubiquitin-proteasome system has been implicated in the pathogenesis of several metabolic disorders, including obesity, diabetes, and non-alcoholic fatty liver disease; however, the mechanisms controlling pathogenic metabolic disorders remain unclear. Transcription factor CCAAT/enhancer binding protein beta (C/EBPß) regulates adipogenic genes. The study showed that the expression level of C/EBPß is post-translationally regulated by the deubiquitinase ubiquitin-specific protease 1 (USP1) and that USP1 expression is remarkably upregulated during adipocyte differentiation and in the adipose tissue of mice fed a high-fat diet (HFD). We found that USP1 directly interacts with C/EBPß. Knock-down of USP1 decreased C/EBPß protein stability and increased its ubiquitination. Overexpression of USP1 regulates its protein stability and ubiquitination, whereas catalytic mutant of USP1 had no effect on them. It suggests that USP1 directly deubiquitinases C/EBPß and increases the protein expression, leading to adipogenesis and lipid accumulation. Notably, the USP1-specific inhibitor ML323-originally developed to sensitize cancer cells to DNA-damaging agents-decreased adipocyte differentiation and lipid accumulation in 3T3-L1 cells without cytotoxicity. Oral gavage of ML323 was administered to HFD-fed mice, which showed weight loss and improvement in insulin and glucose sensitivity. Both fat mass and adipocyte size in white adipose tissues were significantly reduced by ML323 treatment, which also reduced the expression of genes involved in adipogenesis and inflammatory responses. ML323 also reduced lipid accumulation, hepatic triglycerides, free fatty acids, and macrophage infiltration in the livers of HFD-fed mice. Taken together, we suggest that USP1 plays an important role in adipogenesis by regulating C/EBPß ubiquitination, and USP1-specific inhibitor ML323 is a potential treatment option and further study by ML323 is needed for clinical application for metabolic disorders.

Tschimganidine reduces lipid accumulation through AMPK activation and alleviates high-fat diet-induced metabolic diseases.

Obesity increases the risk of mortality and morbidity because it results in hypertension, heart disease, and type 2 diabetes. Therefore, there is an urgent need for pharmacotherapeutic drugs to treat obesity. We performed a screening assay using natural products with anti-adipogenic properties in 3T3-L1 cells and determined that tschimganidine, a terpenoid from the Umbelliferae family, inhibited adipogenesis. To evaluate the anti-obesity effects of tschimganidine in vivo. Mice were fed either a normal chow diet (NFD) or a high-fat chow diet (HFD) with or without tschimganidine for 12 weeks. Treatment with tschimganidine decreased lipid accumulation and adipogenesis, accompanied by reduced expression of adipogenesis and lipid accumulation-related factors. Tschimganidine significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and decreased that of AKT. Depletion of AMPK relieved the reduction in lipid accumulation resulting from tschimganidine treatment. Moreover, tschimganidine administration drastically reduced the weight and size of both gonadal white adipose tissue (WAT) and blood glucose levels in high-fat diet-induced obese mice. We suggest that tschimganidine is a potent antiobesity agent, which impedes adipogenesis and improves glucose homeostasis. Tschimganidine can then be evaluated for clinical application as a therapeutic agent. [BMB Reports 2023; 56(4): 246-251].

Ablation of the deubiquitinase USP15 ameliorates nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) occurs due to the accumulation of fat in the liver, leading to fatal liver diseases such as nonalcoholic steatohepatitis (NASH) and cirrhosis. Elucidation of the molecular mechanisms underlying NAFLD is critical for its prevention and therapy. Here, we observed that deubiquitinase USP15 expression was upregulated in the livers of mice fed a high-fat diet (HFD) and liver biopsies of patients with NAFLD or NASH. USP15 interacts with lipid-accumulating proteins such as FABPs and perilipins to reduce ubiquitination and increase their protein stability. Furthermore, the severity of NAFLD induced by an HFD and NASH induced by a fructose/palmitate/cholesterol/trans-fat (FPC) diet was significantly ameliorated in hepatocyte-specific USP15 knockout mice. Thus, our findings reveal an unrecognized function of USP15 in the lipid accumulation of livers, which exacerbates NAFLD to NASH by overriding nutrients and inducing inflammation. Therefore, targeting USP15 can be used in the prevention and treatment of NAFLD and NASH.

MicroRNA let-7a suppresses breast cancer cell migration and invasion through downregulation of C-C chemokine receptor type 7.

INTRODUCTION: C-C chemokine receptor type 7 (CCR7) plays an important role in chemotactic and metastatic responses in various cancers, including breast cancer. In the present study, the authors demonstrated that microRNA (miRNA) let-7a downregulates CCR7 expression and directly influences the migration and invasion of breast cancer cells. METHODS: The expression of CCR7, its ligand CCL21, and let-7a was detected in breast cancer cell lines and in breast cancer patient tissues. Synthetic let-7a and an inhibitor of let-7a were transfected into MDA-MB-231 and MCF-7 breast cancer cells, respectively, and cell proliferation, cell migration, and invasion assays were performed. To confirm the fact that 3'UTR of CCR7 is a direct target of let-7a, a luciferase assay for the reporter gene expressing the let-7a binding sites of CCR7 3'UTR was used. An in vivo invasion animal model system using transparent zebrafish embryos was also established to determine the let-7a effect on breast cancer cell invasion. RESULTS: First, a higher expression of both CCR7 and CCL21 in malignant tissues than in their normal counterparts from breast cancer patients was observed. In addition, a reverse correlation in the expression of CCR7 and let-7a in breast cancer cell lines and breast cancer patient tissues was detected. Synthetic let-7a decreased breast cancer cell proliferation, migration, and invasion, as well as CCR7 protein expression in MDA-MB-231 cells. The let-7a inhibitor reversed the let-7a effects on the MCF-7 cells. The 3'UTR of CCR7 was confirmed as a direct target of let-7a by using the luciferase assay for the reporter gene expressing let-7a CCR7 3'UTR binding sites. Notably, when analyzing in vivo invasion, MDA-MB 231 cells after synthetic let-7a transfection were unable to invade the vessels in zebrafish embryos. CONCLUSIONS: The results from the present study suggest that targeting of CCL21-CCR7 signaling is a valid approach for breast cancer therapy and that let-7a directly binds to the 3'UTR of CCR7 and blocks its protein expression, thereby suppressing migration and invasion of human breast cancer cells. Furthermore, the present study underscores the therapeutic potential of let-7a as an antitumor and antimetastatic manager in breast cancer patients.

Is it possible to introduce an interview to the Korean Medical Licensing Examination to assess professional attributes?: a survey-based observational study

PURPOSE: This study aimed to gather opinions from medical educators on the possibility of introducing an interview to the Korean Medical Licensing Examination (KMLE) to assess professional attributes. Specifically following topics were dealt with: the appropriate timing and tool to assess unprofessional conduct; the possiblity of prevention of unprofessional conduct by introducing an interview to the KMLE; and the possibility of implementation of an interview to the KMLE. METHODS: A cross-sectional study approach based on a survey questionnaire was adopted. We analyzed 104 pieces of news about doctors' unprofessional conduct to determine the deficient professional attributes. We derived 24 items of unprofessional conduct and developed the questionnaire and surveyed 250 members of the Korean Society of Medical Education 2 times. Descriptive statistics, cross-tabulation analysis, and Fisher's exact test were applied to the responses. The answers to the open-ended questions were analyzed using conventional content analysis. RESULTS: In the survey, 49 members (19.6%) responded. Out of 49, 24 (49.5%) responded in the 2nd survey. To assess unprofessional conduct, there was no dominant timing among basic medical education (BME), KMLE, and continuing professional development (CPD). There was no overwhelming assessment tool among written examination, objective structured clinical examination, practice observation, and interview. Response rates of "impossible" (49.0%) and "possible" (42.9%) suggested an interview of the KMLE prevented unprofessional conduct. In terms of implementation, "impossible" (50.0%) was selected more often than "possible" (33.3%). CONCLUSION: Professional attributes should be assessed by various tools over the period from BME to CPD. Hence, it may be impossible to introduce an interview to assess professional attributes to the KMLE, and a system is needed such as self-regulation by the professional body rather than licensing examination.

Reduced miR-371b-5p expression drives tumor progression via CSDE1/RAC1 regulation in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer; however, specific prognostic biomarkers have not yet been developed. In this study, we identified dysregulated microRNAs (miRNAs) in TNBC by profiling miRNA and mRNA expression. In patients with TNBC, miR-371b-5p expression was reduced, and miR-371b-5p overexpression significantly mitigated TNBC cell growth, migration, and invasion. In addition, we found that expression of cold shock domain-containing protein E1 (CSDE1), a direct target gene of miR-371b-5p, was upregulated in TNBC cells, and inhibition of CSDE1 expression alleviated TNBC cell growth by regulating RAC1 transcription. Mechanistically, CSDE1, phosphorylated C-terminal domain (p-CTD) of RNA polymerase II (RNAPII), and CDK7 form a complex, and downregulation of CSDE1 leads to weak interaction between RNAPII p-CTD and CDK7, resulting in a decrease in RNAPII p-CTD expression to reduce RAC1 transcript levels in CSDE1-deficient TNBC cells. Our data demonstrate that miR-371b-5p is a tumor-suppressive miRNA that regulates the CSDE1/Rac1 axis and could be a potential prognostic biomarker for TNBC.

Alterations in cell proliferation related gene expressions in gastric cancer.

Gastric cancer remains the fourth most prevalent cancer and the second leading cause of cancer-related death in the world. The predominant form of gastric cancer is adenocarcinoma, which originates from glandular epithelium of the gastric mucosa. The major risk factors for gastric cancer include diet, individual genetic variation, and, most importantly, infection with Helicobacter pylori (H. pylori). Certain strains of H. pylori assisted by some of its virulence factors seem to play a critical role in gastric cancer development. Several of these H. pylori virulence factors, which influence cellular proliferation signaling, have been identified. In addition, changes in the expression of several cell proliferation regulating genes accompany or cause the progression of gastric cancer. These changes include modifications of cell cycle regulators, oncogene activation, tumor suppressor inactivation, and miRNA profile alterations. Many of these changes result from H. pylori infection, although their impact on the cellular proliferation system underlying gastric cancer development has not yet been fully elucidated. We review certain features of gastric cancer, the role of H. pylori infection in its etiology and pathogenesis, and gene expression changes during gastric carcinogenesis.

Galectin-3 increases gastric cancer cell motility by up-regulating fascin-1 expression.

BACKGROUND & AIMS: Galectin-3 is a beta-galactoside-binding protein that increases gastric cancer cell motility in response to integrin signaling and is highly expressed in gastric tumor cells. Galectin-3 induces cytoskeletal remodeling to increase cell motility, but the mechanisms of this process are not understood. We investigated the effects of galectin-3 on fascin-1, an actin-bundling protein. METHODS: We collected malignant and normal tissues from gastric cancer patients and examined the expression levels of galectin-3 and fascin-1. We silenced galectin-3 expression in human gastric cancer cell lines using small interfering RNA and lenti-viral constructs and determined the effects on fascin-1 expression, cell motility, and invasion. RESULTS: Malignant gastric tissues expressed high levels of galectin-3 and fascin-1, compared with normal gastric tissues. Silencing of galectin-3 resulted in altered cancer cell morphology, reduced fascin-1 expression, decreased cell motility, and reduced malignant cell invasion. Galectin-3 overexpression reversed these effects. Silencing of fascin-1 also reduced cell motility and caused changes in cell shape, as did silencing of galectin-3. Furthermore, galectin-3 silencing inhibited the interaction between glycogen synthase kinase (GSK)-3beta, beta-catenin, and T-cell factor (TCF) 4, and the binding of beta-catenin/TCF-4 to the fascin-1 promoter. Nuclear localization of GSK-3beta and beta-catenin were not detected when galectin-3 was silenced. Overexpression of mutated galectin-3 (with mutations in the GSK-3beta binding and phosphorylation motifs) did not increase fascin-1 levels, in contrast to overexpression of wild-type galectin-3. CONCLUSIONS: Galectin-3 increases cell motility by up-regulating fascin-1 expression. Galectin-3 might be a potential therapeutic target for the prevention and treatment of gastric cancer progression.

A study on evaluator factors affecting physician-patient interaction scores in clinical performance examinations: a single medical school experience.

BACKGRUOUND: This study is an analysis of evaluator factors affecting physician-patient interaction (PPI) scores in clinical performance examination (CPX). The purpose of this study was to investigate possible ways to increase the reliability of the CPX evaluation. METHODS: The six-item Yeungnam University Scale (YUS), four-item analytic global rating scale (AGRS), and one-item holistic rating scale (HRS) were used to evaluate student performance in PPI. A total of 72 fourth-year students from Yeungnam University College of Medicine in Korea participated in the evaluation with 32 faculty and 16 standardized patient (SP) raters. The study then examined the differences in scores between types of scale, raters (SP vs. faculty), faculty specialty, evaluation experience, and level of fatigue as time passes. RESULTS: There were significant differences between faculty and SP scores in all three scales and a significant correlation among raters' scores. Scores given by raters on items related to their specialty were lower than those given by raters on items out of their specialty. On the YUS and AGRS, there were significant differences based on the faculty's evaluation experience; scores by raters who had three to ten previous evaluation experiences were lower than others' scores. There were also significant differences among SP raters on all scales. The correlation between the YUS and AGRS/HRS declined significantly according to the length of evaluation time. CONCLUSION: In CPX, PPI score reliability was found to be significantly affected by the evaluator factors as well as the type of scale.

Galectin-1 accelerates high-fat diet-induced obesity by activation of peroxisome proliferator-activated receptor gamma (PPARγ) in mice.

Galectin-1 contains a carbohydrate-recognition domain (CRD) as a member of the lectin family. Here, we investigated whether galectin-1 regulates adipogenesis and lipid accumulation. Galectin-1 mRNA is highly expressed in metabolic tissues such as the muscle and adipose tissues. Higher mRNA expression of galectin-1 was detected in white adipose tissues (WATs) of mice that were fed a high-fat diet (HFD) than in those of mice fed a normal-fat diet (NFD). Protein expression of galectin-1 also increased during adipocyte differentiation. Galectin-1 silencing inhibited the differentiation of 3T3-L1 cells and the expression of lipogenic factors, such as PPARγ, C/EBPα, FABP4, and FASN at both mRNA and protein levels. Lactose, an inhibitor by the binding with CRD of galectin-1 in extracellular matrix, did not affect adipocyte differentiation. Galectin-1 is localized in multiple cellular compartments in 3T3-L1 cells. However, we found that DMI (dexamethasone, methylisobutylxanthine, insulin) treatment increased its nuclear localization. Interestingly, galectin-1 interacted with PPARγ. Galectin-1 overexpression resulted in increased PPARγ expression and transcriptional activity. Furthermore, we prepared galectin-1-knockout (Lgals1-/-) mice and fed a 60% HFD. After 10 weeks, Lgals1-/- mice exhibited lower body weight and gonadal WAT (gWAT) mass than wild-type mice. Fasting glucose level was also lower in Lgals1-/-mice than that in wild-type mice. Moreover, lipogenic genes were significantly downregulated in the gWATs and liver tissues from Lgals1-/- mice. Pro-inflammatory cytokines, such as CCL2, CCL3, TNFα, and F4/80, as well as macrophage markers, were also drastically downregulated in the gWATs and liver tissues of Lgals1-/- mice. In addition, Lgals1-/-mice showed elevated expression of genes involved in thermogenesis in the brown adipose tissue. Collectively, galectin-1 exacerbates obesity of mice fed HFD by increment of PPARγ expression and activation. Our findings suggest that galectin-1 could be a potential therapeutic target for obesity and needed further study for clinical application.

Extracellular Superoxide Dismutase Prevents Skin Aging by Promoting Collagen Production through the Activation of AMPK and Nrf2/HO-1 Cascades.

With aging, the skin becomes thin and drastically loses collagen. Extracellular superoxide dismutase (EC-SOD), also known as superoxide dismutase (SOD) 3, is the major SOD in the extracellular matrix of the tissues and is well-known to maintain the reduction‒oxidation homeostasis and matrix components of such tissues. However, the role of EC-SOD in aging-associated reductions of skin thickness and collagen production is not well-studied. In this study, we compared the histological differences in the dorsal skin of EC-SOD‒overexpressing transgenic mice (Sod3+/+) of different age groups with that in wild-type mice and also determined the underlying signaling mechanism. Our data showed that the skin thickness in Sod3+/+ mice significantly increased with aging compared with that in wild-type male mice. Furthermore, Sod3+/+ mice had promoted collagen production through the activation of adenosine monophosphate-activated protein kinase and Nrf2/HO-1 pathways in aged mice. Interestingly, subcutaneous injection of adeno-associated virus‒overexpressing EC-SOD exhibited increased skin thickness and collagen expression. Furthermore, combined recombinant EC-SOD and dihydrotestosterone treatment synergistically elevated collagen production through the activation of TGFß in human dermal fibroblasts. Altogether, these results showed that EC-SOD prevents skin aging by promoting collagen production in vivo and in vitro. Therefore, we propose that EC-SOD may be a potential therapeutic target for antiaging in the skin.

Histone demethylase KDM4C controls tumorigenesis of glioblastoma by epigenetically regulating p53 and c-Myc.

Glioblastoma is the most lethal brain tumor and its pathogenesis remains incompletely understood. KDM4C is a histone H3K9 demethylase that contributes to epigenetic regulation of both oncogene and tumor suppressor genes and is often overexpressed in human tumors, including glioblastoma. However, KDM4C's roles in glioblastoma and the underlying molecular mechanisms remain unclear. Here, we show that KDM4C knockdown significantly represses proliferation and tumorigenesis of glioblastoma cells in vitro and in vivo that are rescued by overexpressing wild-type KDM4C but not a catalytic dead mutant. KDM4C protein expression is upregulated in glioblastoma, and its expression correlates with c-Myc expression. KDM4C also binds to the c-Myc promoter and induces c-Myc expression. Importantly, KDM4C suppresses the pro-apoptotic functions of p53 by demethylating p53K372me1, which is pivotal for the stability of chromatin-bound p53. Conversely, depletion or inhibition of KDM4C promotes p53 target gene expression and induces apoptosis in glioblastoma. KDM4C may serve as an oncogene through the dual functions of inactivation of p53 and activation of c-Myc in glioblastoma. Our study demonstrates KDM4C inhibition as a promising therapeutic strategy for targeting glioblastoma.

Silencing of galectin-3 changes the gene expression and augments the sensitivity of gastric cancer cells to chemotherapeutic agents.

Galectin-3 is known to modulate cell proliferation and apoptosis and is highly expressed in human cancers, but its function in gastric cancer is still controversial. Here, we examined the role of galectin-3 in gastric cancer cells by silencing it with synthetic double-stranded siRNA. After silencing of galectin-3, cell numbers decreased and cell shape changed. Galectin-3 siRNA treatment also induced G(1) arrest. DNA microarray analysis was used to assess changes in gene expression following galectin-3 silencing. We found that silencing of galectin-3 caused changes in gene expression. RT-PCR and real-time PCR were utilized for validation of the changes found in microarray studies. Western blot analysis confirmed changes in the expression of proteins of interest: cyclin D1, survivin, XIAP, XAF, PUMA, and GADD45alpha. Generally, it tended to increase the expression of several pro-apoptotic genes, and to decrease the expression of cell cycle progressive genes. We also confirmed that changes in the expression of these genes were caused by galectin-3 overexpression. Finally, we demonstrated that silencing of galectin-3 enhanced apoptosis induction with chemotherapeutic agents by further reducing the expression of anti-apoptotic and/or cell survival molecules such as survivin, cyclin D1, and XIAP, and increasing the expression of pro-apoptotic XAF-1. We conclude that galectin-3 is involved in cancer progression and malignancy by modulating the expression of several relevant genes, and inhibition of galectin-3 may be an approach to improve chemotherapy of gastric cancers.

Non-classical role of Galectin-3 in cancer progression: translocation to nucleus by carbohydrate-recognition independent manner.

Galectin-3 is a carbohydrate-binding protein and regulates diverse functions, including cell proliferation and differentiation, mRNA splicing, apoptosis induction, immune surveillance and inflammation, cell adhesion, angiogenesis, and cancer-cell metastasis. Galectin-3 is also recommended as a diagnostic or prognostic biomarker of various diseases, including heart disease, kidney disease, and cancer. Galectin-3 exists as a cytosol, is secreted in extracellular spaces on cells, and is also detected in nuclei. It has been found that galectin-3 has different functions in cellular localization: (i) Extracellular galectin-3 mediates cell attachment and detachment. (ii) cytosolic galectin-3 regulates cell survival by blocking the intrinsic apoptotic pathway, and (iii) nuclear galectin-3 supports the ability of the transcriptional factor for target gene expression. In this review, we focused on the role of galectin-3 on translocation from cytosol to nucleus, because it happens in a way independent of carbohydrate recognition and accelerates cancer progression. We also suggested here that intracellular galecin-3 could be a potent therapeutic target in cancer therapy. [BMB Reports 2020; 53(4): 173-180].