Targeting pyruvate dehydrogenase kinase 1 overcomes EGFR C797S mutation-driven osimertinib resistance in non-small cell lung cancer

Osimertinib, a selective third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), effectively targets the EGFR T790M mutant in non-small cell lung cancer (NSCLC). However, the newly identified EGFR C797S mutation confers resistance to osimertinib. In this study, we explored the role of pyruvate dehydrogenase kinase 1 (PDK1) in osimertinib resistance. Patients exhibiting osimertinib resistance initially displayed elevated PDK1 expression. Osimertinib-resistant cell lines with the EGFR C797S mutation were established using A549, NCI-H292, PC-9, and NCI-H1975 NSCLC cells for both in vitro and in vivo investigations. These EGFR C797S mutant cells exhibited heightened phosphorylation of EGFR, leading to the activation of downstream oncogenic pathways. The EGFR C797S mutation appeared to increase PDK1-driven glycolysis through the EGFR/AKT/HIF-1α axis. Combining osimertinib with the PDK1 inhibitor leelamine helped successfully overcome osimertinib resistance in allograft models. CRISPR-mediated PDK1 knockout effectively inhibited tumor formation in xenograft models. Our study established a clear link between the EGFR C797S mutation and elevated PDK1 expression, opening new avenues for the discovery of targeted therapies and improving our understanding of the roles of EGFR mutations in cancer progression.

Morroniside Protects C2C12 Myoblasts from Oxidative Damage Caused by ROS-Mediated Mitochondrial Damage and Induction of Endoplasmic Reticulum Stress

Oxidative stress contributes to the onset of chronic diseases in various organs, including muscles. Morroniside, a type of iridoid glycoside contained in Cornus officinalis, is reported to have advantages as a natural compound that prevents various diseases. However, the question of whether this phytochemical exerts any inhibitory effect against oxidative stress in muscle cells has not been well reported. Therefore, the current study aimed to evaluate whether morroniside can protect against oxidative damage induced by hydrogen peroxide (H2O2) in murine C2C12 myoblasts. Our results demonstrate that morroniside pretreatment was able to inhibit cytotoxicity while suppressing H2O2-induced DNA damage and apoptosis. Morroniside also significantly improved the antioxidant capacity in H2O2-challenged C2C12 cells by blocking the production of cellular reactive oxygen species and mitochondrial superoxide and increasing glutathione production. In addition, H2O2-induced mitochondrial damage and endoplasmic reticulum (ER) stress were effectively attenuated by morroniside pretreatment, inhibiting cytoplasmic leakage of cytochrome c and expression of ER stress-related proteins. Furthermore, morroniside neutralized H2O2-mediated calcium (Ca2+) overload in mitochondria and mitigated the expression of calpains, cytosolic Ca2+-dependent proteases. Collectively, these findings demonstrate that morroniside protected against mitochondrial impairment and Ca2+-mediated ER stress by minimizing oxidative stress, thereby inhibiting H2O2-induced cytotoxicity in C2C12 myoblasts.

Inhibition of SIRT7 overcomes sorafenib acquired resistance by suppressing ERK1/2 phosphorylation via the DDX3X-mediated NLRP3 inflammasome in hepatocellular carcinoma

AIMS

Sirtuin 7 (SIRT7) plays an important role in tumor development, and has been characterized as a potent regulator of cellular stress. However, the effect of SIRT7 on sorafenib acquired resistance remains unclear and a possible anti-tumor mechanism beyond this process in HCC has not been clarified. We examined the therapeutic potential of SIRT7 and determined whether it functions synergistically with sorafenib to overcome chemoresistance.

METHODS

Cancer Genome Atlas-liver HCC data and unbiased gene set enrichment analyses were used to identify SIRT7 as a potential effector molecule in sorafenib acquired resistance. Two types of SIRT7 chemical inhibitors were developed to evaluate its therapeutic properties when synergized with sorafenib. Mass spectrometry was performed to discover a direct target of SIRT7, DDX3X, and DDX3X deacetylation levels and protein stability were explored. Moreover, an in vivo xenograft model was used to confirm anti-tumor effect of SIRT7 and DDX3X chemical inhibitors combined with sorafenib.

RESULTS

SIRT7 inhibition mediated DDX3X depletion can re-sensitize acquired sorafenib resistance by disrupting NLRP3 inflammasome assembly, finally suppressing hyperactive ERK1/2 signaling in response to NLRP3 inflammasome-mediated IL-1β inhibition.

CONCLUSIONS

SIRT7 is responsible for sorafenib acquired resistance, and its inhibition would be beneficial when combined with sorafenib by suppressing hyperactive pro-cell survival ERK1/2 signaling.

NINJ1 mediates inflammatory cell death, PANoptosis, and lethality during infection conditions and heat stress

Innate immunity provides the first line of defense through multiple mechanisms, including pyrogen production and cell death. While elevated body temperature during infection is beneficial to clear pathogens, heat stress (HS) can lead to inflammation and pathology. Links between pathogen exposure, HS, cytokine release, and inflammation have been observed, but fundamental innate immune mechanisms driving pathology during pathogen exposure and HS remain unclear. Here, we use multiple genetic approaches to elucidate innate immune pathways in infection or LPS and HS models. Our results show that bacteria and LPS robustly increase inflammatory cell death during HS that is dependent on caspase-1, caspase-11, caspase-8, and RIPK3 through the PANoptosis pathway. Caspase-7 also contributes to PANoptosis in this context. Furthermore, NINJ1 is an important executioner of this cell death to release inflammatory molecules, independent of other pore-forming executioner proteins, gasdermin D, gasdermin E, and MLKL. In an in vivo HS model, mortality is reduced by deleting NINJ1 and fully rescued by deleting key PANoptosis molecules. Our findings suggest that therapeutic strategies blocking NINJ1 or its upstream regulators to prevent PANoptosis may reduce the release of inflammatory mediators and benefit patients.

Natural Product-Based Glycolysis Inhibitors as a Therapeutic Strategy for Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide. Targeted therapy against the epidermal growth factor receptor (EGFR) is a promising treatment approach for NSCLC. However, resistance to EGFR tyrosine kinase inhibitors (TKIs) remains a major challenge in its clinical management. EGFR mutation elevates the expression of hypoxia-inducible factor-1 alpha to upregulate the production of glycolytic enzymes, increasing glycolysis and tumor resistance. The inhibition of glycolysis can be a potential strategy for overcoming EGFR-TKI resistance and enhancing the effectiveness of EGFR-TKIs. In this review, we specifically explored the effectiveness of pyruvate dehydrogenase kinase inhibitors and lactate dehydrogenase A inhibitors in combating EGFR-TKI resistance. The aim was to summarize the effects of these natural products in preclinical NSCLC models to provide a comprehensive understanding of the potential therapeutic effects. The study findings suggest that natural products can be promising inhibitors of glycolytic enzymes for the treatment of EGFR-TKI-resistant NSCLC. Further investigations through preclinical and clinical studies are required to validate the efficacy of natural product-based glycolytic inhibitors as innovative therapeutic modalities for NSCLC.

Central 5-HTergic hyperactivity induces myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)-like pathophysiology

OBJECTIVES

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a significant medical challenge, with no indisputable pathophysiological mechanism identified to date.

METHODS

Based on clinical clues, we hypothesized that 5-hydroxytryptamine (5-HT) hyperactivation is implicated in the pathogenic causes of ME/CFS and the associated symptoms. We experimentally evaluated this hypothesis in a series of mouse models.

RESULTS

High-dose selective serotonin reuptake inhibitor (SSRI) treatment induced intra- and extracellular serotonin spillover in the dorsal raphe nuclei of mice. This condition resulted in severe fatigue (rota-rod, fatigue rotating wheel and home-cage activity tests) and ME/CFS-associated symptoms (nest building, plantar and open field test), along with dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis response to exercise challenge. These ME/CFS-like features induced by excess serotonin were additionally verified using both a 5-HT synthesis inhibitor and viral vector for Htr1a (5-HT1A receptor) gene knockdown.

CONCLUSIONS

Our findings support the involvement of 5-HTergic hyperactivity in the pathophysiology of ME/CFS. This ME/CFS-mimicking animal model would be useful for understanding ME/CFS biology and its therapeutic approaches.

Association of Visceral Fat Obesity, Sarcopenia, and Myosteatosis with Non-Alcoholic Fatty Liver Disease without Obesity

BACKGROUND/AIMS

To investigate whether non-alcoholic fatty liver disease (NAFLD) in individuals without generalized obesity is associated with visceral fat obesity (VFO), sarcopenia, and/or myosteatosis.

METHODS

This cross-sectional analysis included 14,400 individuals (7,470 men) who underwent abdominal computed tomography scans during routine health examinations. The total abdominal muscle area (TAMA) and skeletal muscle area (SMA) at the 3rd lumbar vertebral level were measured. The SMA was divided into the normal attenuation muscle area (NAMA) and low attenuation muscle area, and the NAMA/TAMA index was calculated. VFO was defined by visceral to subcutaneous fat ratio, sarcopenia by body mass index-adjusted SMA, and myosteatosis by the NAMA/TAMA index. NAFLD was diagnosed with ultrasonography.

RESULTS

Of the 14,400 individuals, 4,748 (33.0%) had NAFLD, and the prevalence of NAFLD among non-obese individuals was 21.4%. In regression analysis, both sarcopenia (men: odds ratio [OR] 1.41, 95% confidence interval [CI] 1.19-1.67, P<0.001; women: OR=1.59, 95% CI 1.40-1.90, P<0.001) and myosteatosis (men: OR=1.24, 95% CI 1.02-1.50, P=0,028; women: OR=1.23, 95% CI 1.04-1.46, P=0.017) were significantly associated with non-obese NAFLD after considering for VFO and other various risk factors, whereas VFO (men: OR=3.97, 95% CI 3.43-4.59 [adjusted for sarcopenia], OR 3.98, 95% CI 3.44-4.60 [adjusted for myosteatosis]; women: OR=5.42, 95% CI 4.53-6.42 [adjusted for sarcopenia], OR=5.33, 95% CI 4.51-6.31 [adjusted for myosteatosis]; all P<0.001) was strongly associated with non-obese NAFLD after adjustment with various known risk factors.

CONCLUSION

In addition to VFO, sarcopenia and/or myosteatosis were significantly associated with non-obese NAFLD.

Regulated cell death pathways and their roles in homeostasis, infection, inflammation, and tumorigenesis

Pyroptosis, apoptosis, necroptosis, and ferroptosis, which are the most well-studied regulated cell death (RCD) pathways, contribute to the clearance of infected or potentially neoplastic cells, highlighting their importance in homeostasis, host defense against pathogens, cancer, and a wide range of other pathologies. Although these four RCD pathways employ distinct molecular and cellular processes, emerging genetic and biochemical studies have suggested remarkable flexibility and crosstalk among them. The crosstalk among pyroptosis, apoptosis and necroptosis pathways is more evident in cellular responses to infection, which has led to the conceptualization of PANoptosis. In this review, we provide a brief overview of the molecular mechanisms of pyroptosis, apoptosis, necroptosis, and ferroptosis and their importance in maintaining homeostasis. We discuss the intricate crosstalk among these RCD pathways and the current evidence supporting PANoptosis, focusing on infectious diseases and cancer. Understanding the fundamental processes of various cell death pathways is crucial to inform the development of new therapeutics against many diseases, including infection, sterile inflammation, and cancer.

Diversity and complexity of cell death: a historical review

Death is the inevitable fate of all living organisms, whether at the individual or cellular level. For a long time, cell death was believed to be an undesirable but unavoidable final outcome of nonfunctioning cells, as inflammation was inevitably triggered in response to damage. However, experimental evidence accumulated over the past few decades has revealed different types of cell death that are genetically programmed to eliminate unnecessary or severely damaged cells that may damage surrounding tissues. Several types of cell death, including apoptosis, necrosis, autophagic cell death, and lysosomal cell death, which are classified as programmed cell death, and pyroptosis, necroptosis, and NETosis, which are classified as inflammatory cell death, have been described over the years. Recently, several novel forms of cell death, namely, mitoptosis, paraptosis, immunogenic cell death, entosis, methuosis, parthanatos, ferroptosis, autosis, alkaliptosis, oxeiptosis, cuproptosis, and erebosis, have been discovered and advanced our understanding of cell death and its complexity. In this review, we provide a historical overview of the discovery and characterization of different forms of cell death and highlight their diversity and complexity. We also briefly discuss the regulatory mechanisms underlying each type of cell death and the implications of cell death in various physiological and pathological contexts. This review provides a comprehensive understanding of different mechanisms of cell death that can be leveraged to develop novel therapeutic strategies for various diseases.

Andrographolide suppresses aerobic glycolysis and induces apoptotic cell death by inhibiting pyruvate dehydrogenase kinase 1 expression

Metabolic disorder is a major characteristic of cancer cells, and controlling genes involved in metabolic shifts can be an effective strategy for cancer treatment. Andrographolide (AG), a diterpenoid lactone, is widely recognized as a natural anticancer drug due to its ability to inhibit cancer growth. The present study aimed to investigate the mechanism underlying the mitochondrial‑mediated anticancer effect of AG by inhibiting pyruvate dehydrogenase kinase 1 (PDK1) expression in lung cancer cells. Cells were treated with AG and PDK1 mRNA and protein expression was determined using reverse transcription‑quantitative PCR and western blotting, respectively. As a result, AG significantly inhibited the viability of human lung cancer cells and suppressed aerobic glycolysis by decreasing lactate generation. AG further decreased the PDK1 protein and mRNA levels in a dose‑dependent manner. AG‑induced cell death was assessed by flow cytometry and fluorescence microscopy. AG induced apoptotic cell death that was associated with the cleavage of poly (ADP ribose) polymerase, activation of caspase‑3, and mitochondrial damage, which was associated with an increase in reactive oxygen species and loss of mitochondrial membrane potential. AG‑induced cell death was partially suppressed via PDK1 overexpression in lung cancer cells. Therefore, the anticancer effects of AG on human lung cancer cells may negatively regulate the expression of PDK1.

Frankincense ameliorates endometriosis via inducing apoptosis and reducing adhesion

Background

Frankincense, a resin derived from trees of the Boswellia genus, has been used as an incense and a type of herbal medicine for treating inflammatory diseases such arthritis, chronic bowel illness, and asthma. While endometriosis is a well-known inflammatory gynecological illness caused by the ectopic attachment and development of uterine tissue over the menstrual cycle, the impact of frankincense on this illness is poorly understood. The purpose of this study was to explore the effects of frankincense on endometriosis.

Methods

We used a network pharmacological assessment, in vitro and in vivo investigations with a human endometriotic cell line as well as a syngeneic uterine transfer mouse model. High-performance liquid chromatographic analysis was used to compare water-extracted frankincense (Fr) to its reference compounds and validate the sample.

Results

A network pharmacological analysis suggested a positive effect of Fr on endometriosis. Fr relieved endometriosis by reducing ectopic endometrial adherence and development, according to both in vivo and in vitro models. We suggested that the ER stress/p53-apoptosis and chemokine-migration/adhesion pathways underlie Fr's anti-endometriotic action using RNA sequencing and bioinformatic analysis.

Conclusion

This study revealed the potential effect of Fr on endometriosis using an experimental investigation. Fr may have the potential to be an effective and safe treatment for endometriosis.

Corrigendum: Water-extracted Prunella vulgaris alleviates endometriosis by reducing aerobic glycolysis

[This corrects the article DOI: 10.3389/fphar.2022.872810.].

Sex Differences of Visceral Fat Area and Visceral-to-Subcutaneous Fat Ratio for the Risk of Incident Type 2 Diabetes Mellitus

BACKGROUND

This study aimed to determine the optimal cut-off values of visceral fat area (VFA) and visceral-to-subcutaneous fat ratio (VSR) for predicting incident type 2 diabetes mellitus (T2DM).

METHODS

A total of 10,882 individuals (6,835 men; 4,047 women) free of T2DM at baseline aged between 30 and 79 years who underwent abdominal computed tomography scan between 2012 and 2013 as a part of routine health check-ups were included and followed. VFA, subcutaneous fat area, and VSR on L3 vertebral level were measured at baseline.

RESULTS

During a median follow-up of 4.8 years, 730 (8.1% for men; 4.3% for women) incident cases of T2DM were identified. Receiver operating characteristic curve analysis showed that the optimal cut-off values of VFA and VSR for predicting incident T2DM were 130.03 cm2 and 1.08 in men, respectively, and 85.7 cm2 and 0.48 in women, respectively. Regardless of sex, higher VFA and VSR were significantly associated with a higher risk of incident T2DM. Compared with the lowest quartiles of VFA and VSR, the highest quartiles had adjusted odds ratios of 2.62 (95% confidence interval [CI], 1.73 to 3.97) and 1.55 (95% CI, 1.14 to 2.11) in men, respectively, and 32.49 (95% CI, 7.42 to 142.02) and 11.07 (95% CI, 3.89 to 31.50) in women, respectively.

CONCLUSION

Higher VFA and VSR at baseline were independent risk factors for the development of T2DM. Sex-specific reference values for visceral fat obesity (VFA ≥130 cm2 or VSR ≥1.0 in men; VFA ≥85 cm2 or VSR ≥0.5 in women) are proposed for the prediction of incident T2DM.

Association between type 2 diabetes and skeletal muscle quality assessed by abdominal computed tomography scan

AIM

To examine the association between type 2 diabetes and the amount and quality of trunk muscle as assessed by computed tomography (CT) scan.

MATERIALS AND METHODS

A total of 20,986 subjects (13,007 men and 7979 women) who underwent abdominal CT scan as part of a routine health check-up were included. The total abdominal muscle area (TAMA) measured at the third lumbar vertebrae was classified into skeletal muscle area (SMA), and intermuscular adipose tissue area. SMA was divided into good quality muscles (normal attenuation muscle area [NAMA]) and poor quality muscles (low attenuation muscle area). NAMA/TAMA index was calculated.

RESULTS

Subjects with type 2 diabetes had higher values of TAMA and SMA but significantly lower values of NAMA and NAMA/TAMA index. Compared with those in the lowest quartile of NAMA/TAMA index, subjects in the highest quartile had metabolically favourable laboratory findings, a lower prevalence of type 2 diabetes (Q1 vs. Q4: 19.3% vs. 9.5% in men, 12.3% vs. 3.0% in women) and inverse association with type 2 diabetes (odds ratio for Q2, Q3, and Q4: 0.87, 0.78, and 0.75 in men; 0.82, 0.70, and 0.68 in women) after multivariable adjustment.

CONCLUSIONS

The amount of good quality muscle on CT scan was associated with a lower prevalence of type 2 diabetes.

Water-Extracted Prunella vulgaris Alleviates Endometriosis by Reducing Aerobic Glycolysis

Endometriosis is a chronic inflammatory disorder caused by abnormal adhesion of endometrial tissue to the outside of the uterus. The combination of surgery, non-steroidal anti-inflammatory drugs, and hormone treatment is well established therapy for endometriosis, however, case reports have showed that high rates of relapse and unpleasant side effect. For these reasons, recently, the studies have been focused on the Warburg-like metabolic shift of endometriosis. Prunella vulgaris is one of traditionally used herbal medicine for inflammatory disease and the anti-estrogenic effects of P. vulgaris is well-established. Therefore, in this work, we evaluated water-extracted P. vulgaris (PV) as a potential treatment for endometriosis. To this, we artificially induced endometriosis in ovarectomized mice by intra-peritoneal inoculation of uterus extracts. PV was orally administered, and PV significantly alleviated endometriosis, particularly the growth of ectopic endometrial lesions in artificially endometriosis-induced mice. For the mechanism study of anti-endometriosis by PV, we designed an in vitro study using human normal endometrial stromal cells (T-HESCs) and human endometrial cell (12Z) obtained from patients with endometriosis. PV strongly induced the apoptosis of 12Z cells rather than T-HESCs by control the activity or expression of aerobic glycolysis enzymes, such as lactate dehydrogenase A (LDHA), pyruvate dehydrogenase A, and pyruvate dehydrogenase kinase 1/3. In addition, lactate production was enhanced, and oxygen consumption rate was suppressed in 12Z cells upon PV treatment. These changes in aerobic glycolysis eventually caused mitochondrial damage following decreased mitochondrial membrane potential and excessive mitochondrial ROS production. Especially, ulsolic acid (UA), one of the compounds in PV considerably led 12Z cell apoptosis with inhibition of LDHA activity. Therefore, UA could be a major active substance of PV in terms of endometriosis inhibitors. In conclusion, this study provides the evidence that the beneficial efficacy of PV for the prevention/treatment of endometriosis.

The effect of first- and third-generation prophylactic antibiotics on hospitalization and medical expenditures for cardiac surgery

BACKGROUND

This study investigated the efficacy of first-generation (cefazolin) and third-generation (ceftizoxime) prophylactic antibiotics in patients undergoing cardiac surgery and the incidence of surgical site infections, hospitalizations, and medical costs.

METHODS

All adult patients (≥ 20 years) undergoing cardiac surgery at one hospital from January 01, 2009, to December 31, 2016, were included in this study. A single prophylactic antibiotic was administered at a dose of 1 g within one hour of the surgical incision and for three days after surgery at eight-hour intervals. After propensity score matching, 194 patients in each antibiotic prophylaxis group (first-generation vs third-generation) were analyzed. Among the 388 patients, the incidence of surgical site infections was compared according to the type of prophylactic antibiotic, and risk factors were evaluated by chi-squared tests followed by multivariate logistic regression analysis.

RESULTS

The incidence of deep surgical site infections was significantly lower in the first-generation group (5.7%) than in the third-generation group (16.5%). The pathogens isolated from the surgical infection sites were similarly distributed in both groups. However, the prevalence of highly infectious gram-positive bacteria was more than that of gram-negative bacteria (67% vs 23%). The preoperative hospitalization duration, mean operation time, and ventilator use time were similar in both groups, but the postoperative hospitalization duration was significantly shorter in the first-generation group (25.5 days) than in the third-generation group (29.8 days). In addition, the medical costs were lower in the first-generation group (20,594 USD) than in the third-generation group (26,488 USD).

CONCLUSION

In conclusion, the first-generation prophylactic antibiotic was better than the third-generation in reducing surgical site infection rates, hospitalization length, and medical expenditures.

Identification and analysis of novel endometriosis biomarkers via integrative bioinformatics

Endometriosis is a gynecological disease prevalent in women of reproductive age, and it is characterized by the ectopic presence and growth of the eutopic endometrium. The pathophysiology and diagnostic biomarkers of endometriosis have not yet been comprehensively determined. To discover molecular markers and pathways underlying the pathogenesis of endometriosis, we identified differentially expressed genes (DEGs) in three Gene Expression Omnibus microarray datasets (GSE11691, GSE23339, and GSE7305) and performed gene set enrichment analysis (GSEA) and protein-protein interaction (PPI) network analyses. We also validated the identified genes via immunohistochemical analysis of tissues obtained from patients with endometriosis or healthy volunteers. A total of 118 DEGs (79 upregulated and 39 downregulated) were detected in each dataset with a lower (fold change) FC cutoff (log2|FC| > 1), and 17 DEGs (11 upregulated and six downregulated) with a higher FC cutoff (log2|FC| > 2). KEGG and GO functional analyses revealed enrichment of signaling pathways associated with inflammation, complement activation, cell adhesion, and extracellular matrix in endometriotic tissues. Upregulation of seven genes (C7, CFH, FZD7, LY96, PDLIM3, PTGIS, and WISP2) out of 17 was validated via comparison with external gene sets, and protein expression of four genes (LY96, PDLIM3, PTGIS, and WISP2) was further analyzed by immunohistochemistry and western blot analysis. Based on these results, we suggest that TLR4/NF-κB and Wnt/frizzled signaling pathways, as well as estrogen receptors, regulate the progression of endometriosis. These pathways may be therapeutic and diagnostic targets for endometriosis.

Drug evaluation based on phosphomimetic PDHA1 reveals the complexity of activity-related cell death in A549 non-small cell lung cancer cells

Cancer cells predominantly generate energy via glycolysis, even in the presence of oxygen, to support abnormal cell proliferation. Suppression of PDHA1 by PDK1 prevents the conversion of cytoplasmic pyruvate into Acetyl-CoA. Several PDK inhibitors have been identified, but their clinical applications have not been successful for unclear reasons. In this study, endogenous PDHA1 in A549 cells was silenced by the CRISPR/Cas9 system, and PDHA1^WT and PDHA1^3SD were transduced. Since PDHA1^3SD cannot be phosphorylated by PDKs, it was used to evaluate the specific activity of PDK inhibitors. This study highlights that PDHA1^WT and PDHA1^3SD A549 cells can be used as a cell-based PDK inhibitor-distinction system to examine the relationship between PDH activity and cell death by established PDK inhibitors. Leelamine, huzhangoside A and otobaphenol induced PDH activity-dependent apoptosis, whereas AZD7545, VER-246608 and DCA effectively enhanced PDHA1 activity but little toxic to cancer cells. Furthermore, the activity of phosphomimetic PDHA1 revealed the complexity of its regulation, which requires further in-depth investigation.

Comparison of the Clinical Process and Outcomes in Patients after Coronavirus Infection 2019 Outbreak

Background and Objectives: The coronavirus infection 2019 (COVID-19) pandemic has affected emergency department (ED) management. Its viral transmission necessitates the use of isolation rooms and personal protective equipment for treating suspected patients, such as those with fever. This delays the time until the first encounter with the patients, thereby increasing the length of stay (LOS) in the ED. We aimed to compare delays in the ED LOS and clinical processes between the COVID-19 period and pre-COVID-19 period. Moreover, we intended to evaluate if the aforementioned delay affected patient outcomes. Materials and Methods: We conducted a single-center, retrospective study in Korea. Patients with fever were compared between the “COVID-19 period” from March 2020 to August 2020 and the “pre-COVID-19 period” from March 2019 to September 2019. We compared the overall ED LOS and individual time variable, including initial diagnostic tests (laboratory tests, radiography), specific diagnostic test (computed tomography), and treatment processes (antibiotics). A logistic regression analysis was conducted to identify the association between hospital admission and patient data. Results: We enrolled 931 and 749 patients during pre- and COVID-19 periods, respectively. Patients with fever remained in the ED for a longer duration during the COVID-19 period (pre-COVID-19:207.7 ± 102.7 min vs. during COVID-19: 223.5 ± 119.4 min, p = 0.004). The total time for performing laboratory tests and radiography displayed significant differences between the two periods, particularly from the time of patient arrival in the ED to the time of issuing the order. The time until antibiotic administration was delayed in the COVID-19 period (pre-COVID-19:195.8 ± 103.3 min vs. during COVID-19: 216.9 ± 108.4 min, p = 0.003). The logistic regression analysis for hospital admission identified ED LOS as an independent factor in both periods. Conclusions: The delay until encountering patients with fever resulted in longer ED LOS during the COVID-19 period; however, it possibly did not increase the hospital admission rates.

Comparison of muscle mass and quality between metabolically healthy and unhealthy phenotypes

OBJECTIVE

The aim of this study was to examine whether higher skeletal muscle mass is associated with a metabolically healthy phenotype and whether muscle quality affects metabolic health.

METHODS

This cross-sectional analysis included 20,659 participants (7,966 women) who underwent abdominal computed tomography scans during health checkups. The total abdominal muscle area (TAMA) on the third lumbar vertebral level was demarcated. Intermuscular adipose tissue and skeletal muscle area were measured. The skeletal muscle area was divided into normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA). The NAMA/TAMA index was calculated. The metabolically unhealthy phenotype was defined as having two or more components of metabolic syndrome or the presence of hypertension or diabetes.

RESULTS

TAMA and skeletal muscle area were not significantly different or even lower in metabolically healthy phenotypes compared with metabolically unhealthy phenotypes. However, metabolically healthy phenotypes had significantly higher NAMA (except in women with obesity) and NAMA/TAMA index than in the metabolically unhealthy phenotypes. In people without obesity, lower NAMA/TAMA index was independently associated with higher risk of the metabolically unhealthy phenotype in the fully adjusted model.

CONCLUSIONS

The metabolically healthy phenotypes had more good-quality muscles than did the metabolically unhealthy phenotypes. These results suggest that not only muscle mass but also muscle quality (i.e., degree of myosteatosis) are associated with metabolic health.

Reference Data and T-Scores of Lumbar Skeletal Muscle Area and Its Skeletal Muscle Indices Measured by CT Scan in a Healthy Korean Population

BACKGROUND

Although computed tomography (CT) is considered the gold standard for investigating skeletal muscles, diagnostic cutoff points for sarcopenia have not been established. We therefore suggested clinically relevant diagnostic cutoff points for sarcopenia based on reference values of skeletal muscle area (SMA) measured by CT scan in a large-sized healthy Asian population.

METHODS

This cross-sectional analysis included 11,845 subjects (7,314 men, 4,531 women) who underwent abdominal CT scans in South Korea. SMA including all muscles on the selected axial images of the L3 lumbar vertebrae level was demarcated using predetermined thresholds (-29 to +150 Hounsfield units). SMA indices (height-, weight-, and body mass index [BMI]-adjusted) were calculated.

RESULTS

When T-score < -2.0 was used as the cutoff for defining sarcopenia, the sex-specific cutoff points of SMA, SMA/height2, SMA/weight, and SMA/BMI were 119.3 and 74.2 cm2, 39.8 and 28.4 cm2/m2, 1.65 and 1.38 cm2/kg, and 4.97 and 3.46 in men and women, respectively. In both sexes, the SMA/BMI values peaked in the 20s and decreased gradually. The SMA/BMI yielded the highest diagnostic rate of sarcopenia (4.2% in men, 8.7% in women), while SMA/height2 provided the lowest yield (2.8% in men, 1.0% in women).

CONCLUSIONS

This is the first study to report the reference values of SMA and skeletal muscle indices (SMIs) measured on CT scans and to suggest cutoff points for diagnosis of sarcopenia based on T-score in Asian subjects. BMI-adjusted index (SMA/BMI) was the best index of CT-measured SMA to reflect the age-related muscle changes and to maximize the diagnostic yield for sarcopenia.

Visit-to-visit changes in fasting blood sugar and the risk for cardiovascular disease and mortality in the Korean population: a nationwide population-based cohort study

OBJECTIVE

The importance of continuous monitoring of fasting blood sugar (FBS) levels of diabetic patients has been established.

MATERIALS AND METHODS

An observational prospective study was conducted. Our analysis included 1,700,796 individuals from the nationwide South Korean National Health Insurance System cohort. FBS variability was measured by standard deviation (SD).

RESULTS

Kaplan-Meier curves demonstrated elevated disease probability in the higher FBS fluctuation group compared with the lower FBS fluctuation group. After adjusting for confounding variables, Cox proportional hazards analysis showed that the hazard ratios of 411 individuals in the highest quartile of SD variation of FBS were 1.77 (95% confidence interval 1.37-2.28, p<0.001) compared with the lowest quartile of SD variation of FBS. The impact of FBS fluctuation on the risk of cardiovascular diseases (CVDs), cerebrovascular diseases, CVD mortality and all-cause mortality in the highest quartiles of diabetic and non-diabetic individuals was statistically significant.

CONCLUSIONS

Visit-to-visit FBS variability has prognostic value for predicting micro- and macrovascular disease, cardiovascular mortality, and all-cause mortality.

Targeting Lactate Dehydrogenase A with Catechin Resensitizes SNU620/5FU Gastric Cancer Cells to 5-Fluorouracil

Resistance to anticancer therapeutics occurs in virtually every type of cancer and becomes a major difficulty in cancer treatment. Although 5-fluorouracil (5FU) is the first-line choice of anticancer therapy for gastric cancer, its effectiveness is limited owing to drug resistance. Recently, altered cancer metabolism, including the Warburg effect, a preference for glycolysis rather than oxidative phosphorylation for energy production, has been accepted as a pivotal mechanism regulating resistance to chemotherapy. Thus, we investigated the detailed mechanism and possible usefulness of antiglycolytic agents in ameliorating 5FU resistance using established gastric cancer cell lines, SNU620 and SNU620/5FU. SNU620/5FU, a gastric cancer cell harboring resistance to 5FU, showed much higher lactate production and expression of glycolysis-related enzymes, such as lactate dehydrogenase A (LDHA), than those of the parent SNU620 cells. To limit glycolysis, we examined catechin and its derivatives, which are known anti-inflammatory and anticancer natural products because epigallocatechin gallate has been previously reported as a suppressor of LDHA expression. Catechin, the simplest compound among them, had the highest inhibitory effect on lactate production and LDHA activity. In addition, the combination of 5FU and catechin showed additional cytotoxicity and induced reactive oxygen species (ROS)-mediated apoptosis in SNU620/5FU cells. Thus, based on these results, we suggest catechin as a candidate for the development of a novel adjuvant drug that reduces chemoresistance to 5FU by restricting LDHA.

Age-related changes in muscle quality and development of diagnostic cutoff points for myosteatosis in lumbar skeletal muscles measured by CT scan

BACKGROUND & AIMS

We have sought to develop proper and useful indices for muscle quality measurements other than muscle attenuation (Hounsfield unit; HU) and to determine the diagnostic cutoff points for myosteatosis by using those indices measured at the L3 lumbar vertebrae level by CT scan.

METHODS

This cross-sectional analysis included 20,664 healthy adult subjects (12,697 men and 7967 women) who underwent abdominal CT scans. Total abdominal muscle area (TAMA), on the L3 vertebra was demarcated using predetermined thresholds. Intermuscular adipose tissue area (IMAT) and skeletal muscle area (SMA) were measured. SMA was divided into normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA). Their various indices were calculated. We identified the sex-specific mean values of NAMA, LAMA, IMAT, and their indices and the cutoff points equivalent to the T-scores in the young reference group.

RESULTS

The mean values of the NAMA and NAMA indices decreased with age in both sexes, LAMA, IMAT, and their indices showed an increasing tendency with age in both sexes. When using T-score < -2.0 as the cutoff for myosteatosis, the sex-specific cutoff points of NAMA, NAMA/BMI, NAMA/TAMA index, and SMA and TAMA attenuation in men and women were 103.0 and 64.5 cm², 4.0 and 2.8, 66.4 and 65.1, 40.2 and 39.9 HU, and 34.1 and 33.5 HU, respectively. Using these cutoff points, the prevalence of myosteatosis by NAMA, NAMA/BMI, NAMA/TAMA index, or SMA or TAMA attenuation ranged from 5.9 to 8.8% in men and from 10.2 to 20.5% in women.

CONCLUSIONS

The NAMA/TAMA index developed in this study was useful for assessing myosteatosis. This is the first study to report the sex-specific diagnostic cutoff points for myosteatosis of trunk muscles based on T-scores measured by CT scans in healthy population. These diagnostic cutoff points may be particularly useful in the treatment and prevention of sarcopenia and myosteatosis.

Paeoniflorin Enhances Endometrial Receptivity through Leukemia Inhibitory Factor

Despite advances in assisted reproductive technology, treatment for deficient endometrial receptivity is a major clinical unmet need. In our previous study, the water extract of Paeonia lactiflora Pall. enhanced endometrial receptivity in vitro and in vivo via induction of leukemia inhibitory factor (LIF), an interleukin (IL)-6 family cytokine. In the present study, we found that paeoniflorin, a monoterpene glycoside, is the major active compound of P. lactiflora. Paeoniflorin significantly improved the embryo implantation rate in a murine model of mifepristone (RU486)-induced implantation failure. In addition, paeoniflorin increased the adhesion of human trophectoderm-derived JAr cells to endometrial Ishikawa cells through the expression of LIF in vitro. Moreover, using the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database of the human endometrium, we confirmed that LIF signaling is a key regulator for improving human endometrial receptivity. Therefore, these results suggest that paeoniflorin might be a potent drug candidate for the treatment of endometrial implantation failure by enhancing endometrial receptivity.

Caesalpinia sappan induces apoptotic cell death in ectopic endometrial 12Z cells through suppressing pyruvate dehydrogenase kinase 1 expression

Endometriosis is a common gynecological disease defined as the growth of endometrial tissues outside the uterus. Although the mechanism underlying the progression of endometriosis has not been fully elucidated, cancer-like aerobic glycolysis is considered to mediate the elevated growth and resistance to apoptosis of endometriotic cells. The heartwood of Caesalpinia sappan L. (family Leguminosae) is a herbal medicinal product used to treat gynecological symptoms, including algomenorrhea and amenorrhea. The results of the present study revealed that endometriotic 12Z cells exhibited more rapid growth than normal endometrial cells (THES). The expression levels of pyruvate dehydrogenase kinase (PDK)1 and 3 and lactate production were higher in 12Z cells than in THES cells. In addition, the 12Z cells were more sensitive to the cytotoxicity of the aqueous extract of C. sappan heartwood (CS) than the THES cells. CS inhibited lactate production and phosphorylation of pyruvate dehydrogenase A by reducing the expression of PDK1. CS also increased mitochondrial reactive oxygen species (ROS) levels, decreased mitochondrial membrane potential and consequently stimulated the apoptosis of 12Z cells. CS-induced cell death was substantially inhibited by exogenous PDK1 expression. In conclusion, CS may be a novel drug candidate for treating endometriosis by inhibiting aerobic glycolysis and inducing ROS-mitochondria-mediated apoptotic cell death.

Hemistepsin A suppresses colorectal cancer growth through inhibiting pyruvate dehydrogenase kinase activity

Most cancer cells primarily produce their energy through a high rate of glycolysis followed by lactic acid fermentation even in the presence of abundant oxygen. Pyruvate dehydrogenase kinase (PDK) 1, an enzyme responsible for aerobic glycolysis via phosphorylating and inactivating pyruvate dehydrogenase (PDH) complex, is commonly overexpressed in tumors and recognized as a therapeutic target in colorectal cancer. Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata Bunge (Compositae). Here, we report that HsA is a PDK1 inhibitor can reduce the growth of colorectal cancer and consequent activation of mitochondrial ROS-dependent apoptotic pathway both in vivo and in vitro. Computational simulation and biochemical assays showed that HsA directly binds to the lipoamide-binding site of PDK1, and subsequently inhibits the interaction of PDK1 with the E2 subunit of PDH complex. As a result of PDK1 inhibition, lactate production was decreased, but oxygen consumption was increased. Mitochondrial ROS levels and mitochondrial damage were also increased. Consistent with these observations, the apoptosis of colorectal cancer cells was promoted by HsA with enhanced activation of caspase-3 and -9. These results suggested that HsA might be a potential candidate for developing a novel anti-cancer drug through suppressing cancer metabolism.

Sarcopenia and Muscle Aging: A Brief Overview

The world is facing the new challenges of an aging population, and understanding the process of aging has therefore become one of the most important global concerns. Sarcopenia is a condition which is defined by the gradual loss of skeletal muscle mass and function with age. In research and clinical practice, sarcopenia is recognized as a component of geriatric disease and is a current target for drug development. In this review we define this condition and provide an overview of current therapeutic approaches. We further highlight recent findings that describe key pathophysiological phenotypes of this condition, including alterations in muscle fiber types, mitochondrial function, nicotinamide adenine dinucleotide (NAD+) metabolism, myokines, and gut microbiota, in aged muscle compared to young muscle or healthy aged muscle. The last part of this review examines new therapeutic avenues for promising treatment targets. There is still no accepted therapy for sarcopenia in humans. Here we provide a brief review of the current state of research derived from various mouse models or human samples that provide novel routes for the development of effective therapeutics to maintain muscle health during aging.

Synthesis and initial screening of lactate dehydrogenase inhibitor activity of 1,3-benzodioxole derivatives

Cancer is one of the main causes of mortality in the world. Many cancer cells produce ATP through high-level lactic acid fermentation catalyzed by lactate dehydrogenase (LDH), which converts pyruvic acid to lactic acid. LDH plays a dominant role in the Warburg effect, wherein aerobic glycolysis is favored over oxidative phosphorylation. Due to the high lactic acid production level in cancer cells, LDH-targeting could be a potential cancer treatment strategy. A few approaches, such as drug treatment, reportedly inhibited LDH activity. In this study, we describe new 1,3-benzodioxole derivatives that might be potential small molecule candidates for LDHA inhibition. The synthesis was carried out by trans-esterification between aryl ester and alcohol groups from piperonyl alcohol. Compounds 2 and 10 exhibited a selective LDHA IC₅₀ value of 13.63 µM and 47.2 µM, respectively. Whereas only compound 10 showed significant cytotoxicity in several lines of cancer cells, especially in human pancreatic cancer PANC-1 cells. These synthesized compounds possess 2 aromatic rings and –CF₃ moiety, which expectedly contributes to LDHA inhibition. The presented products have the potential to become a promising LDHA inhibitor drug candidate.

Ninjurin1 deficiency aggravates colitis development by promoting M1 macrophage polarization and inducing microbial imbalance

Disruption of colonic homeostasis caused by aberrant M1/M2 macrophage polarization and dysbiosis contributes to inflammatory bowel disease (IBD) pathogenesis. However, the molecular factors mediating colonic homeostasis are not well characterized. Here, we found that Ninjurin1 (Ninj1) limits colon inflammation by regulating macrophage polarization and microbiota composition under homeostatic conditions and during colitis development. Ninj1 deletion in mice induced hypersusceptibility to colitis, with increased prevalence of colitogenic Prevotellaceae strains and decreased immunoregulatory Lachnospiraceae strains. Upon co-housing (CoH) with WT mice, Ninj1^-/- mice showed increased Lachnospiraceae and decreased Prevotellaceae abundance, with subsequent improvement of colitis. Under homeostatic conditions, M1 macrophage frequency was higher in the Ninj1^-/- mouse colons than wild-type (WT) mouse colons, which may contribute to increased basal colonic inflammation and microbial imbalance. Following colitis induction, Ninj1 expression was increased in macrophages; meanwhile Ninj1^-/- mice showed severe colitis development and impaired recovery, associated with decreased M2 macrophages and escalated microbial imbalance. In vitro, Ninj1 knockdown in mouse and human macrophages activated M1 polarization and restricted M2 polarization. Finally, the transfer of WT macrophages ameliorated severe colitis in Ninj1^-/- mice. These findings suggest that Ninj1 mediates colonic homeostasis by modulating M1/M2 macrophage balance and preventing extensive dysbiosis, with implications for IBD prevention and therapy.

6-sialyllactose ameliorates dihydrotestosterone-induced benign prostatic hyperplasia through suppressing VEGF-mediated angiogenesis

Benign prostatic hyperplasia (BPH), a common disease in elderly males, is accompanied by non-malignant growth of prostate tissues, subsequently causing hypoxia and angiogenesis. Although VEGF-related angiogenesis is one of the therapeutic targets of prostate cancer, there is no previous study targeting angiogenesis for treatment of BPH. Dihydrotestosterone (DHT)-induced expressions of vascular endothelial growth factor (VEGF) in prostate epithelial RWPE-1 cells and human umbilical vascular endothelial cells (HUVECs). Conditioned media (CM) from DHT-treated RWPE-1 cells were transferred to HUVECs. Then, 6SL inhibited proliferation, VEGFR-2 activation, and tube formation of HUVECs transferred with CM from DHT-treated RWPE-1 cells. In the rat BPH model, 6SL reduced prostate weight, size, and thickness of the prostate tissue. Formation of vessels in prostatic tissues were also reduced with 6SL treatment. We found that 6SL has an ameliorative effect on in vitro and in vivo the BPH model via inhibition of VEGFR-2 activation and subsequent angiogenesis. These results suggest that 6SL might be a candidate for development of novel BPH drugs.

Akap12beta supports asymmetric heart development via modulating the Kupffer’s vesicle formation in zebrafish

The vertebrate body plan is accomplished by left-right asymmetric organ development and the heart is a representative asymmetric internal organ which jogs to the left-side. Kupffer’s vesicle (KV) is a spherical left-right organizer during zebrafish embryogenesis and is derived from a cluster of dorsal forerunner cells (DFCs). Cadherin1 is required for collective migration of a DFC cluster and failure of DFC collective migration by Cadherin1 decrement causes KV malformation which results in defective heart laterality. Recently, loss of function mutation of A-kinase anchoring protein 12 (AKAP12) is reported as a high-risk gene in congenital heart disease patients. In this study, we demonstrated the role of akap12β in asymmetric heart development. The akap12β, one of the akap12 isoforms, was expressed in DFCs which give rise to KV and akap12β-deficient zebrafish embryos showed defective heart laterality due to the fragmentation of DFC clusters which resulted in KV malformation. DFC-specific loss of akap12β also led to defective heart laterality as a consequence of the failure of collective migration by cadherin1 reduction. Exogenous akap12β mRNA not only restored the defective heart laterality but also increased cadherin1 expression in akap12β morphant zebrafish embryos. Taken together, these findings provide the first experimental evidence that akap12β regulates heart laterality via cadherin1.

Age-Related Decrease in Skeletal Muscle Mass Is an Independent Risk Factor for Incident Nonalcoholic Fatty Liver Disease: A 10-Year Retrospective Cohort Study

Background/Aims

Sarcopenia has emerged as an important risk factor for nonalcoholic fatty liver disease (NAFLD). Although aging is the main cause of sarcopenia, the longitudinal association between age-related body composition changes and NAFLD development has not been fully investigated. Thus, we evaluated whether age-related increased fat mass or decreased muscle mass is an independent risk factor for incident NAFLD.

Methods

We conducted a retrospective cohort study involving 4,398 initially NAFLD-free subjects who underwent routine health examinations during 2004 to 2005 and returned for a follow-up during 2014 to 2015. Their body composition was measured by bioelectrical impedance analysis, and fatty liver was diagnosed by abdominal ultrasonography.

Results

At the 10-year follow-up, 591 out of 4,398 participants (13.4%) had developed NAFLD. In men and women, both increased fat mass and decreased appendicular skeletal muscle mass (ASM) with aging were significantly associated with incident NAFLD after adjustment. A subgroup analysis according to the baseline obesity status showed that increased fat mass was significantly associated with incident NAFLD in obese and nonobese subjects. However, decreased ASM was significantly associated with incident NAFLD in nonobese but not in obese subjects. According to ΔASM tertiles (decrease of ASM), the odds ratios for incident NAFLD in nonobese subjects were 1.38 (95% confidence interval [CI], 1.04 to 1.84) for the second tertile and 1.81 (95% CI, 1.34 to 2.45) for the third tertile after adjustment (p=0.001).

Conclusions

A progressive increase in fat mass and a loss of ASM with aging were significantly associated with incident NAFLD. This association was more prominent in nonobese subjects.

Abstract P3-03-02: Redo sentinel lymph node biopsy for ipsilateral breast tumor recurrence after breast conserving surgery with negative sentinel nodes: A pooled analysis from a systematic review and two institutes

Background:Cases of redo sentinel lymph node biopsy (SLNB) are growing according to the increase of ipsilateral breast tumor recurrence (IBTR) after breast-conservative surgery (BCS). To evaluate a feasibility of redo SLNB in patients with IBTR after negative SLN, we conveyed a pooled analysis using data from a systematic review and two institutes.

Materials and methods:A systematic search of PubMed was conducted to identify data of patient level from publications evaluating redo SLNB for cases with IBTR. Eligible patients who underwent BCS and were confirmed as negative axilla after SLNB were identified. An identification rate (IR) and a false-negative rate (FNR) were calculated. To identify FNR, we only included cases with back-up axillary node dissection (ALND) from retrieved data.

Results:In a systematic review, a total of 197 peer-reviewed publications were retrieved, of which 19 papers included patients who met eligibility criteria. Data from 464 patients were collected. In two-institutes, 38 cases with same criteria were identified. A total of 502 patient's data were pooled. The IR of redo-SLNB was 71.7% (360/502) in pooled data. For the FNR, data from 147 patients with back-up ALND after SLNB was analyzed. The FNR and accuracy of redo-SLNB were 9.8% (5/51) and 97% (142/147).

Conclusions:We found that the IR and the FNR of redo SLNB were 71.7% and 9.8%, respectively. Redo SLNB is reliable procedure for axillary staging in patients with IBTR after negative SLNB.

Citation Format: Yoon C-i, Bae SJ, Choi JE, Cha CH, Park SE, Ahn SG, Jeong J. Redo sentinel lymph node biopsy for ipsilateral breast tumor recurrence after breast conserving surgery with negative sentinel nodes: A pooled analysis from a systematic review and two institutes [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-02.

Ninjurin1 positively regulates osteoclast development by enhancing the survival of prefusion osteoclasts

Osteoclasts (OCs) are bone-resorbing cells that originate from hematopoietic stem cells and develop through the fusion of mononuclear myeloid precursors. Dysregulation of OC development causes bone disorders such as osteopetrosis, osteoporosis, and rheumatoid arthritis. Although the molecular mechanisms underlying osteoclastogenesis have been well established, the means by which OCs maintain their survival during OC development remain unknown. We found that Ninjurin1 (Ninj1) expression is dynamically regulated during osteoclastogenesis and that Ninj1^-/- mice exhibit increased trabecular bone volume owing to impaired OC development. Ninj1 deficiency did not alter OC differentiation, transmigration, fusion, or actin ring formation but increased Caspase-9-dependent intrinsic apoptosis in prefusion OCs (preOCs). Overexpression of Ninj1 enhanced the survival of mouse macrophage/preOC RAW264.7 cells in osteoclastogenic culture, suggesting that Ninj1 is important for the survival of preOCs. Finally, analysis of publicly available microarray data sets revealed a potent correlation between high NINJ1 expression and destructive bone disorders in humans. Our data indicate that Ninj1 plays an important role in bone homeostasis by enhancing the survival of preOCs.

Protective role of skeletal muscle mass against progression from metabolically healthy to unhealthy phenotype

OBJECTIVE

Metabolically healthy individuals are known to be resistant to cardiovascular disease development. However, a considerable fraction of those individuals shows deteriorated metabolic health over time. Although skeletal muscle is the primary insulin-responsive target organ, a longitudinal investigation of the skeletal muscle mass in relation to the development of metabolically unhealthy phenotype has not been performed. We aimed to evaluate whether greater skeletal muscle mass is an independent protective factor for the development of metabolically unhealthy phenotype.

DESIGN, PARTICIPANTS AND MEASUREMENTS

We conducted a retrospective cohort study with 9033 metabolically healthy volunteers who underwent routine health examinations in 2012 and a follow-up examination in 2016. Obesity was defined as Asian-Pacific body mass index criterion ≥25 kg/m² . Subjects with fewer than two risk factors (elevated blood pressure, triglyceride, glucose, high-sensitivity C-reactive protein, insulin resistance and decreased high-density lipoprotein cholesterol levels) were characterized as metabolically healthy using Wildman criteria.

RESULTS

At the 4-year follow-up, approximately one-fourth of the nonobese participants and half of the participants with obesity showed metabolic deterioration. In nonobese men and women, higher appendicular skeletal muscle mass (ASM)/weight at baseline was significantly associated with decreased risk of metabolic deterioration. Compared to the lowest quartile of ASM/weight, the adjusted odds ratios (95% confidence intervals) of the highest quartile were 0.68 (0.52-0.89) in nonobese men and 0.64 (0.46-0.90) in nonobese women. However, this association was not observed in obese subjects.

CONCLUSIONS

Greater skeletal muscle mass at baseline is significantly associated with maintenance of metabolically healthy status, especially in nonobese individuals.

Gender differences of visceral fat area for predicting incident type 2 diabetes in Koreans

AIMS

Visceral fat accumulation is known to be an independent risk factor for type 2 diabetes. We aimed to determine the optimal cutoff values of visceral fat area (VFA) for predicting incident type 2 diabetes in Koreans.

METHODS

Our study population consisted of 13,004 individuals initially free of type 2 diabetes the ages between 20 and 69 years, who underwent routine health examinations between January 2012 and December 2012 and returned for follow-up examinations between January 2016 and December 2016. VFA values were derived from bioelectrical impedance analysis (BIA) at baseline.

RESULTS

During a median follow-up of 4.02 years, a total of 481 (4.6% for men and 2.3% for women) incident cases of type 2 diabetes were identified. According to the receiver operating characteristic (ROC) curve, the optimal VFA cutoff values for predicting incident type 2 diabetes were 118.8 cm² in men and 82.6 cm² in women, respectively. In a multivariable-adjusted model including obesity and glycemic status, the odds ratios (ORs) of VFA over 120 cm² in men and 80 cm² in women were 1.72 and 3.56, respectively.

CONCLUSIONS

Higher VFA at baseline was an independent risk factor for developing type 2 diabetes and the optimal VFA cutoff values were markedly different between men and women. Therefore, sex-specific reference values for visceral fat obesity such that men with a VFA ≥120 cm² and women with a VFA ≥80 cm² should be considered to predict incident type 2 diabetes.

Abstract P4-02-11: Accuracy of breast magnetic resonance imaging has limited value to reduce the margin-positive rate: A study in relation to the molecular subtypes

Background: Newly released guideline standardizing a negative margin after breast-conservative surgery (BCS) as “no ink on tumor” by SSO-ASTRO stressed the importance of estimation tumor extent with comprehensive breast imaging studies. To evaluate clinical value of breast magnetic resonance imaging (MRI) in patients with BCS, we compared the degree of correlation between MRI-pathology and ultrasonography (US)-pathology according to subtypes. In addition, we investigated the margin-positive rates and secondary operation rates for margin clearance.

Methods: We identified patients with invasive breast cancer who had preoperative breast MRI and ultrasound between 2011 and 2016. We excluded patients having large tumor more than 5cm or multiple tumors or undergoing mastectomy. Patients were classified into 4 subtypes based on the immunohistochemistry; luminal A, luminal B/HER2, HER2, triple-negative breast cancer (TNBC). Lin's concordance correlation coefficient was used to measure the agreement between the MRI or US and tumor extent. Tumor extent was defined as pathologic tumor size including in situ carcinoma. Margin-positivity was assessed based on intraoperative frozen examination.

Results: A total 516 patients with single tumor undergoing BCS were included. Means of tumor size were 1.99 ± 0.91 cm by pathologic examination, 1.91 ± 1.01 cm by MRI, and 1.76 ± 0.92 cm by US, respectively. The correlation coefficient of MRI-pathology was significantly higher than that of US-pathology (r=0.6975 vs. 0.6211, P=0.001). A superiority of MRI than US in measuring pathologic extent was only observed in TNBC (r=0.8089 vs. 0.6014, P&lt;0.001), whereas the agreement between the MRI or US and tumor extents was low in the HER2 (MRI: 0.3509, US: 0.3165). Also, the margin-positive rate was higher in HER2 (luminal A, 11.6%; luminal B/HER2, 17.5%; HER2, 29.6%; TNBC, 17.8%; P=0.0382). In the post-hoc test, the HER2 was more likely to have positive margin compared to Luminal A (P=0.0039). There is no significant difference in secondary operation as margin clearance according to the subtypes (P&gt;0.999).

Margin positive and re-excision rates according to the subtypes Luminal A (n=302)Luminal B (n=80)HER2 (n=27)TNBC (n=107)P valuePositive margin35 (11.6)14 (17.5)8 (29.6)19 (17.8)0.0382Re-excision14 (4.6)4 (5.0)1 (3.7)5 (4.7)&gt;0.9999

Conclusions: Given a superiority of MRI to US in preoperative assessment, MRI-guided BCS did not reduce the margin-positive rate in TNBC. In the HER2, size correlation of MRI-pathology was very low, and the margin-positive rate was high. Collectively, our findings suggest that accuracy of MRI has limited value to reduce the margin-positive rate.

Citation Format: Bae SJ, Ahn SG, Yoon C, Cha YJ, Jeong J. Accuracy of breast magnetic resonance imaging has limited value to reduce the margin-positive rate: A study in relation to the molecular subtypes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-02-11.

SAMHD1 acetylation enhances its deoxynucleotide triphosphohydrolase activity and promotes cancer cell proliferation

SAM domain and HD domain containing protein 1 (SAMHD1) is a deoxynucleotide triphosphohydrolase (dNTPase) that inhibits retroviruses by depleting intracellular deoxynucleotide triphosphates (dNTPs) in non-cycling myeloid cells. Although SAMHD1 is expressed ubiquitously throughout the human body, the molecular mechanisms regulating its enzymatic activity and function in non-immune cells are relatively unexplored. Here, we demonstrate that the dNTPase activity of SAMHD1 is regulated by acetylation, which promotes cell cycle progression in cancer cells. SAMHD1 is acetylated at residue lysine 405 (K405) in vitro and in vivo by an acetylatransferase, arrest defective protein 1 (ARD1). Acetylated SAMHD1 wildtype proteins have enhanced dNTPase activity in vitro, whereas non-acetylated arginine substituted mutants (K405R) do not. K405R mutant expressing cancer cells have reduced G1/S transition and slower proliferation compared to wildtype. SAMHD1 acetylation levels are strongest during the G1 phase, indicating a role during G1 phase. Collectively, these findings suggest that SAMHD1 acetylation enhances its dNTPase activity and promotes cancer cell proliferation. Therefore, SAMHD1 acetylation may be a potent therapeutic target for cancer treatment.

ARD1-mediated aurora kinase A acetylation promotes cell proliferation and migration

Aurora kinase A (AuA) is a prerequisite for centrosome maturation, separation, and mitotic spindle assembly, thus, it is essential for cell cycle regulation. Overexpression of AuA is implicated in poor prognosis of many types of cancer. However, the regulatory mechanisms underlying the functions of AuA are still not fully understood. Here, we report that AuA colocalizes with arrest defective protein 1 (ARD1) acetyltransferase during cell division and cell migration. Additionally, AuA is acetylated by ARD1 at lysine residues at positions 75 and 125. The double mutations at K75/K125 abolished the kinase activity of AuA. Moreover, the double mutant AuA exhibited diminished ability to promote cell proliferation and cell migration. Mechanistic studies revealed that AuA acetylation at K75/K125 promoted cell proliferation via activation of cyclin E/CDK2 and cyclin B1. In addition, AuA acetylation stimulated cell migration by activating the p38/AKT/MMP-2 pathway. Our findings indicate that ARD1-mediated acetylation of AuA enhances cell proliferation and migration, and probably contributes to cancer development.

Ninjurin1 Assembles Into a Homomeric Protein Complex Maintained by N-linked Glycosylation

Ninjurin1 (Ninj1) is a cell surface protein known as a homophilic adhesion molecule. Previous studies have shown a trans-interaction of Ninj1 between immune cells and endothelial cells; however, little is known about Ninj1 modification and structure in the cis-interaction. We showed that Ninj1 assembles into a homomeric complex via a cis-interaction mediated by the intracellular region and N-glycosylation at Asn⁶⁰ . We identified cis-interaction between Ninj1 proteins using CFP- and YFP-tagged Ninj1 by Förster resonance energy transfer using a confocal microscope and fluorescence-activated cell sorter. We further observed the Ninj1 homomeric complexes composed of two to six monomeric Ninj1 molecules by a formaldehyde cross-linking assay. Co-immunoprecipitation assays with epitope-tagged truncated Ninj1 suggested that the intracellular region encompassing Leu¹⁰¹ -Ala¹¹⁰ participates in Ninj1 homomer assembly. Ninj1 N-glycosylation was characterized by treatment of tunicamycin and substitution of Asn to Gln or Ala. Fluorescence-activated cell sorting-based Förster resonance energy transfer assays further demonstrated that N-glycosylation is indispensable for the Ninj1 cis-interaction, and a formaldehyde cross-linking assay confirmed that interruption of N-glycosylation by Asn substitution disrupted Ninj1 homomeric complex formation. In silico analysis revealed that Ninj1 is highly conserved in vertebrates and that the conserved sequence contains an N-glycosylation motif and cis-interacting intracellular region, which participate in Ninj1 homomer assembly. Taken together, these data show that Ninj1 assembles into a homomeric protein complex and that N-glycosylation is a prerequisite for Ninj1 homomer assembly. J. Cell. Biochem. 118: 2219-2230, 2017. © 2017 Wiley Periodicals, Inc.

Pilot study on the correlation between skin auto-fluorescence and serum antioxidant enzyme: skin auto-fluorescence is negatively associated with levels of malondialdehyde

BACKGROUND/PURPOSE

Various methods have been used to objectively record skin changes. However, estimating the intrinsic and extrinsic aging of skin remains a challenge. Our objective was to study intrinsic skin aging with respect to patient age and extrinsic photo-aging of human dorsal (photo-exposed) and volar (photo-protected) forearm in vivo through skin auto-fluorescence (AF). We also examined the correlations between serum antioxidant enzyme, malondialdehyde(MDA), and skin AF.

METHODS

37 healthy volunteers were enrolled. We measured skin AF and its heterogeneity on the dorsal and volar forearms. We also examined serum concentration of catalase, superoxide dismutase, vitamin E, and MDA levels in every participant.

RESULTS

In photo-protected areas, skin AF intensity in the 40 years or older group was significantly higher compared to the group less than 40 years-old. On the other hand, heterogeneity value was significantly higher in the less than 40 years-old group in photo-protected area. With respect to serum antioxidant enzyme and MDA level, only MDA level showed a negative correlation with skin AF intensity in photo-exposed area.

CONCLUSION

We determined that skin AF intensity of the photo-protected area reflects intrinsic skin aging. In addition, degree of photo-aging could be indirectly inferred by skin AF of photo-exposed area and serum MDA level.

Risk of progression to diabetes from prediabetes defined by HbA1c or fasting plasma glucose criteria in Koreans

AIMS

To examine the abilities of HbA1c and fasting plasma glucose (FPG) criteria predicting 5-year progression rate to diabetes in Korean adults with prediabetes.

METHODS

Participants included 17,971 Koreans (aged 20-79years) who underwent routine medical check-ups at a mean interval of 5.2years (3.1-6.7years). Prediabetes was defined as FPG 5.6-6.9mmol/l or HbA1c 5.7-6.4% (39-46mmol/mol). Incident diabetes was defined as FPG⩾7.0mmol/l, HbA1c⩾6.5% (48mmol/mol), or initiation of antidiabetic medications.

RESULTS

At baseline, the prevalence of prediabetes was 30.6% (n=5495) by FPG and 20.4% (n=3664) by HbA1c criteria. The 5-year progression rate to diabetes was significantly higher in prediabetes identified by HbA1c than by FPG tests (14.7% vs. 10.4%, P<0.001). Of individuals diagnosed with prediabetes by only one test, those by HbA1c alone had a higher risk of progression to diabetes than those diagnosed by FPG alone (6.0% vs. 3.9%, P<0.001). Receiver operating characteristic curve analysis showed that area under the curve was greater for HbA1c (0.855, 95% CI 0.840-0.870) than for FPG (0.830, 0.813-0.846) (P=0.016). After adjustment for conventional risk factors, the odds ratio (OR) of developing diabetes was higher in participants with prediabetes identified by HbA1c (OR 9.91, 8.24-11.9) than by FPG (OR 7.29, 5.97-8.89) (P=0.026).

CONCLUSIONS

Although fewer individuals with prediabetes were identified by HbA1c than by FPG criteria, the ability to predict progression to diabetes was stronger for HbA1c than for FPG in Koreans.

The circulating sphingosine-1-phosphate level predicts incident fracture in postmenopausal women: a 3.5-year follow-up observation study

A high level of circulating sphingosine-1-phosphate (S1P) is associated with a high incidence of osteoporotic fracture and a high rate of an insufficient response to bisphosphonate therapy.

INTRODUCTION

Sphingosine-1-phosphate (S1P) is a significant regulator of bone metabolism. Recently, we found that a high plasma S1P level is associated with low bone mineral density (BMD), high levels of bone resorption markers (BRMs), and a high risk of prevalent vertebral fracture in postmenopausal women. We investigated the possibility that S1P is a predictor of incident fracture.

METHODS

A total of 248 postmenopausal women participated in this longitudinal study and were followed up for a mean duration of 3.5 years (untreated [n = 76] or treated with bisphosphonate or hormone replacement therapy [n = 172]). The baseline plasma S1P level and prevalent and incident fracture occurrence were assessed.

RESULTS

A high S1P level was significantly associated with a higher rate of prevalent fracture after adjusting for femoral neck (FN) BMD, BRM, and potential confounders (odds ratio = 2.05; 95 % confidence interval [CI] = 1.03-4.00). Incident fractures occurred more frequently in the highest S1P tertile (T3) than in the lower two tertiles (T1-2) after adjusting for confounders, including baseline FN BMD, prevalent fracture, antiosteoporotic medication, annualized changes in FN BMD, BRM, and potential confounders (hazard ratio = 5.52; 95 % CI = 1.04-56.54). Insufficient response to bisphosphonate therapy occurred more frequently in T3 than T1-2 (odds ratio = 4.43; 95 % CI = 1.02-21.25).

CONCLUSIONS

The plasma S1P level may be a potential predictor of fracture occurrence and an insufficient response to bisphosphonate therapy in postmenopausal women.

Abiotic stress of ambient cold temperature regulates the host receptivity to pathogens by cell surfaced sialic acids

Ambient cold temperature, as an abiotic stress, regulates the survival, stability, transmission, and infection of pathogens. However, the effect of cold temperature on the host receptivity to the pathogens has not been fully studied. In this study, the expression of terminal α-2,3- and α-2,6-sialic acids were increased in murine lung tissues, especially bronchial epithelium, by exposure to cold condition. The expression of several sialyltransferases were also increased by exposure to cold temperature. Furthermore, in human bronchial epithelial BEAS-2B cells, the expressions of α-2,3- and α-2,6-sialic acids, and mRNA levels of sialyltransferases were increased in the low temperature condition at 33 °C. On the other hand, the treatment of Lith-Gly, a sialyltransferase inhibitor, blocked the cold-induced expression of sialic acids on surface of BEAS-2B cells. The binding of influenza H1N1 hemagglutinin (HA) toward BEAS-2B cells cultured at low temperature condition was increased, compared to 37 °C. In contrast, the cold-increased HA binding was blocked by treatment of lithocholicglycine and sialyl-N-acetyl-D-lactosamines harboring α-2,3- and α-2,6-sialyl motive. These results suggest that the host receptivity to virus at cold temperature results from the expressions of α-2,3- and α-2,6-sialic acids through the regulation of sialyltransferase expression.