Mechanisms Controlling PD-L1 Expression in Cancer.

The engagement of programmed cell death protein 1 (PD-1; encoded by the PDCD1 gene) receptor expressed on activated T cells and its ligand, programmed death-ligand 1 (PD-L1; encoded by the CD274 gene), is a major co-inhibitory checkpoint signaling that controls T cell activities. Various types of cancers express high levels of PD-L1 and exploit PD-L1/PD-1 signaling to evade T cell immunity. Blocking the PD-L1/PD-1 pathway has consistently shown remarkable anti-tumor effects in patients with advanced cancers and is recognized as the gold standard for developing new immune checkpoint blockade (ICB) and combination therapies. However, the response rates of anti-PD-L1 have been limited in several solid tumors. Therefore, furthering our understanding of the regulatory mechanisms of PD-L1 can bring substantial benefits to patients with cancer by improving the efficacy of current PD-L1/PD-1 blockade or other ICBs. In this review, we provide current knowledge of PD-L1 regulatory mechanisms at the transcriptional, posttranscriptional, post-translational, and extracellular levels, and discuss the implications of these findings in cancer diagnosis and immunotherapy.

Metformin Promotes Antitumor Immunity via Endoplasmic-Reticulum-Associated Degradation of PD-L1.

Metformin has been reported to possess antitumor activity and maintain high cytotoxic T lymphocyte (CTL) immune surveillance. However, the functions and detailed mechanisms of metformin's role in cancer immunity are not fully understood. Here, we show that metformin increases CTL activity by reducing the stability and membrane localization of programmed death ligand-1 (PD-L1). Furthermore, we discover that AMP-activated protein kinase (AMPK) activated by metformin directly phosphorylates S195 of PD-L1. S195 phosphorylation induces abnormal PD-L1 glycosylation, resulting in its ER accumulation and ER-associated protein degradation (ERAD). Consistently, tumor tissues from metformin-treated breast cancer patients exhibit reduced PD-L1 levels with AMPK activation. Blocking the inhibitory signal of PD-L1 by metformin enhances CTL activity against cancer cells. Our findings identify a new regulatory mechanism of PD-L1 expression through the ERAD pathway and suggest that the metformin-CTLA4 blockade combination has the potential to increase the efficacy of immunotherapy.

PD-L1: From cancer immunotherapy to therapeutic implications in multiple disorders.

The PD-L1/PD-1 signaling pathway is the gold standard for cancer immunotherapy. Therapeutic antibodies targeting PD-1, such as nivolumab (Opdivo) and pembrolizumab (Keytruda), and PD-L1, including atezolizumab (Tecentriq), durvalumab (Imfinzi), and avelumab (Bavencio) have received Food and Drug Administration approval and are currently being used to treat various cancers. Traditionally, PD-L1 is known as an immune checkpoint protein that binds to the PD-1 receptor on its surface to inhibit the activity of T cells, which are the primary effector cells in antitumor immunity. However, it also plays a role in cancer progression, which goes beyond traditional understanding. Here, we highlight the multifaceted mechanisms of action of PD-L1 in cancer cell proliferation, transcriptional regulation, and systemic immune suppression. Moreover, we consider the potential role of PD-L1 in the development and pathogenesis of diseases other than cancer, explore PD-L1-focused therapeutic approaches for these diseases, and assess their clinical relevance. Through this review, we hope to provide deeper insights into the PD-L1/PD-1 signaling pathway and present a broad perspective on potential therapeutic approaches for cancer and other diseases.

Developmental screening of neurodevelopmental disorders before age 6: a nationwide health screening program.

BACKGROUND: We aimed to investigate the association between developmental screening before 24 months of age and neurodevelopmental disorders (NDDs) at 4-6 years of age. METHODS: We included 922,899 newborn born between 2014 and 2016 registered in National Health Insurance Service (NHIS). Developmental screening was administered at 9-12 and 18-24 months old with the Korean Developmental Screening Test for Infants & Children (K-DST). Diagnoses of NDDs was based on the World Health Organization's International Classification of Diseases, Tenth Revision (ICD-10), provided by the NHIS database. RESULTS: Among 637,277 individuals who underwent screening at 9-12 and 18-24 months, Screen-positivity (defined as summed score < -2 standard deviation) for gross motor domain at 9-12 months was significantly associated with the incidence of autism spectrum disorder (aHR, 2.24; 95% CI, 1.80-2.80) and cerebral palsy (aHR, 4.81; 95% CI, 3.62-6.38). Screening positive at language domain at 18-24 months old was associated with autism spectrum disorder (aHR 5.50; 95% CI, 4.31- 7.02) and developmental language disorder (aHR 8.67; 95% CI, 7.27-10.33) at 4-6 years of age. CONCLUSION: Widespread nationwide implementation of screening programs before 24 months was effective in identifying NDDs at 4-6 years of age. Further strategies integrating with referral and intervention systems should be established. IMPACT: We investigated the screening effect of nationwide developmental screening program on neurodevelopmental disorders using nationwide data. Gross motor delay during infancy was significant predictor of later neurodevelopmental disorders. Language, cognitive, and social delay before 24 months of age was associated with later autism spectrum disorders and developmental language disorders. Widespread nationwide implementation of screening programs before 24 months was effective in identifying NDDs at 4-6 years of age and should be encouraged.

Association between preterm birth and asthma and atopic dermatitis in preschool children: a nationwide population-based study.

Asthma and atopic dermatitis (AD) are representative chronic diseases in childhood. This study aimed to investigate the impact of preterm birth on the incidence and severity of asthma and AD in children, as well as to identify neonatal risk factors for asthma and AD. We used health claims data recorded between 2007 and 2014 in the Korean National Health Insurance Service database. We recruited 2,224,476 infants born between 2007 and 2014 and divided them into three groups: 3518 of extremely preterm (EP) infants (< 28 weeks of gestational age (GA)), 82,579 of other preterm (OP) infants (28-36 weeks of GA), and 2,138,379 of full-term (FT) infants (> 37 weeks of GA). We defined asthma as > 3 episodes of clinical visits in a year before 6 years of age, early asthma as onset at < 2 years of age, and severe asthma as > 1 event of status asthmaticus or admission to a hospital via an emergency room. AD was defined as ≥ 3 diagnoses in a year before 6 years of age, early AD as onset at < 2 years of age, and severe AD as prescription of high-potency topical steroids or immunosuppressants. An association of preterm birth with asthma and AD was assessed using inverse probability of treatment-weighted multivariable Cox regression analysis. Cardiorespiratory conditions, such as respiratory distress syndrome, bronchopulmonary dysplasia, patent ductus arteriosus, and pulmonary hypertension, significantly increased the risk of asthma. Specifically, bronchopulmonary dysplasia emerged as a significant risk factor for both severe and early-onset asthma (odds ratio (OR) 1.36, 95% CI 1.21-1.37 for severe asthma; OR 1.55, 95% CI 1.30-1.85 for early asthma), while it was associated with a decreased risk of AD (OR 0.86, 95% CI 0.80-0.92). Neonatal sepsis, jaundice, and retinopathy of prematurity were also identified as significant risk factors for later asthma. A stepwise increase in the risk of asthma with an increasing degree of prematurity was observed, with the OP group showing an adjusted hazard ratio (aHR) of 1.24 (95% CI: 1.22-1.26) and the EP group showing an aHR of 1.51 (95% CI: 1.41-1.63). Conversely, preterm birth was inversely associated with the risk of AD, with aHRs of 0.73 (95% CI: 0.67-0.79) for the OP group and 0.88 (95% CI: 0.87-0.89) for the EP group. Conclusion Preterm children have a significantly higher risk of asthma and lower risk of AD, with cardiorespiratory conditions significantly increasing the risk of asthma. Thus, we highlight the need for targeted respiratory management strategies for this high-risk population. What is Known: •Asthma and atopic dermatitis are prevalent chronic diseases in childhood, reducing the quality of life of children. •Preterm birth was associated with an increased risk of asthma, but few large nationwide studies. •Research on the relationship between preterm birth and pediatric atopic dermatitis is controversial, with few large nationwide studies. What is New: • Preterm children, especially born before 28 weeks of gestational age, had a significantly higher risk of asthma and lower risk of atopic dermatitis. • Cardiorespiratory comorbidities such as RDS, BPD, PDA, and pulmonary hypertension in neonatal period are prominent risk factors for asthma. • Preterm children are vulnerable to both early-onset and severe asthma.

Ephrin receptor A10 monoclonal antibodies and the derived chimeric antigen receptor T cells exert an antitumor response in mouse models of triple-negative breast cancer.

Expression of the receptor tyrosine kinase ephrin receptor A10 (EphA10), which is undetectable in most normal tissues except for the male testis, has been shown to correlate with tumor progression and poor prognosis in several malignancies, including triple-negative breast cancer (TNBC). Therefore, EphA10 could be a potential therapeutic target, likely with minimal adverse effects. However, no effective clinical drugs against EphA10 are currently available. Here, we report high expression levels of EphA10 in tumor regions of breast, lung, and ovarian cancers as well as in immunosuppressive myeloid cells in the tumor microenvironment. Furthermore, we developed anti-EphA10 monoclonal antibodies (mAbs) that specifically recognize cell surface EphA10, but not other EphA family isoforms, and target tumor regions precisely in vivo with no apparent accumulation in other organs. In syngeneic TNBC mouse models, we found that anti-EphA10 mAb clone #4 enhanced tumor regression, therapeutic response rate, and T cell-mediated antitumor immunity. Notably, the chimeric antigen receptor T cells derived from clone #4 significantly inhibited TNBC cell viability in vitro and tumor growth in vivo. Together, our findings suggest that targeting EphA10 via EphA10 mAbs and EphA10-specific chimeric antigen receptor-T cell therapy may represent a promising strategy for patients with EphA10-positive tumors.

Feeding practice during infancy is associated with attention-deficit/hyperactivity disorder and autism spectrum disorder: a population-based study in South Korea.

Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are representative neurodevelopmental disorders. Using a nationwide database, we aimed to investigate whether feeding practices in infancy (breastfeeding and the timing of supplementary food introduction) could impact ADHD or ASD development. We evaluated 1,173,448 children aged 4-6 months who were included in the National Screening Program for Infants and Children (NHSPIC) between 2008 and 2014. We observed individuals until 6-7 years of age. Data on feeding type (milk feeding: exclusive breastfeeding [EBF], partial breastfeeding [PBF], exclusive formula feeding [EFF] at 4-6 months of age; supplementary food introduction: < 6 or > 6 months of age) were obtained from the NHSPIC, and diagnoses were based on the International Classification of Diseases, Tenth Revision. In a generalized linear model, children who received EBF had significantly lower incidence of both ADHD (odds ratio [OR]: 0.77, 95% confidence interval [CI]: 0.72-0.82) and ASD (OR: 0.64, 95% CI: 0.60-0.67) than that of children who received EFF. PBF also had a significant protective effect on both ADHD (0.91; 0.85-0.98), and ASD (0.89; 0.83-0.95). The timing of supplementary food introduction was not associated with either ADHD or ASD, although there was an increased risk of ASD in the EFF infants who had supplementary food introduced at > 6 months of age.  Conclusion: Our study strengthens and supports the beneficial effect of breastfeeding on neurodevelopmental disorders in children. Breastfeeding should be encouraged and recommended to promote desirable neurodevelopmental outcomes. What is Known: • Breastfeeding is beneficial for the overall health of children, including neurodevelopmental outcomes and cognitive functions. What is New: • Breastfeeding, especially exclusive breastfeeding, was protective against neurodevelopmental disorders. • The effect of the timing of supplementary food introduction was limited.

TMEM9-v-ATPase Activates Wnt/ß-Catenin Signaling Via APC Lysosomal Degradation for Liver Regeneration and Tumorigenesis.

BACKGROUND AND AIMS: How Wnt signaling is orchestrated in liver regeneration and tumorigenesis remains elusive. Recently, we identified transmembrane protein 9 (TMEM9) as a Wnt signaling amplifier. APPROACH AND RESULTS: TMEM9 facilitates v-ATPase assembly for vesicular acidification and lysosomal protein degradation. TMEM9 is highly expressed in regenerating liver and hepatocellular carcinoma (HCC) cells. TMEM9 expression is enriched in the hepatocytes around the central vein and acutely induced by injury. In mice, Tmem9 knockout impairs hepatic regeneration with aberrantly increased adenomatosis polyposis coli (Apc) and reduced Wnt signaling. Mechanistically, TMEM9 down-regulates APC through lysosomal protein degradation through v-ATPase. In HCC, TMEM9 is overexpressed and necessary to maintain ß-catenin hyperactivation. TMEM9-up-regulated APC binds to and inhibits nuclear translocation of ß-catenin, independent of HCC-associated ß-catenin mutations. Pharmacological blockade of TMEM9-v-ATPase or lysosomal degradation suppresses Wnt/ß-catenin through APC stabilization and ß-catenin cytosolic retention. CONCLUSIONS: Our results reveal that TMEM9 hyperactivates Wnt signaling for liver regeneration and tumorigenesis through lysosomal degradation of APC.

RIPK3 activation induces TRIM28 derepression in cancer cells and enhances the anti-tumor microenvironment.

BACKGROUND: Necroptosis is emerging as a new target for cancer immunotherapy as it is now recognized as a form of cell death that increases tumor immunogenicity, which would be especially helpful in treating immune-desert tumors. De novo synthesis of inflammatory proteins during necroptosis appears especially important in facilitating increased anti-tumor immune responses. While late-stage transcription mediated by NF-κB during cell death is believed to play a role in this process, it is otherwise unclear what cell signaling events initiate this transactivation of inflammatory genes. METHODS: We employed tandem-affinity purification linked to mass spectrometry (TAP-MS), in combination with the analysis of RNA-sequencing (RNA-Seq) datasets to identify the Tripartite Motif Protein 28 (TRIM28) as a candidate co-repressor. Comprehensive biochemical and molecular biology techniques were used to characterize the role of TRIM28 in RIPK3 activation-induced transcriptional and immunomodulatory events. The cell composition estimation module was used to evaluate the correlation between RIPK3/TRIM28 levels and CD8+ T cells or dendritic cells (DC) in all TCGA tumors. RESULTS: We identified TRIM28 as a co-repressor that regulates transcriptional activity during necroptosis. Activated RIPK3 phosphorylates TRIM28 on serine 473, inhibiting its chromatin binding activity, thereby contributing to the transactivation of NF-κB and other transcription factors, such as SOX9. This leads to elevated cytokine expression, which then potentiates immunoregulatory processes, such as DC maturation. The expression of RIPK3 has a significant positive association with the tumor-infiltrating immune cells populations in various tumor type, thereby activating anti-cancer responses. CONCLUSION: Our data suggest that RIPK3 activation-dependent derepression of TRIM28 in cancer cells leads to increased immunostimulatory cytokine production in the tumor microenvironment, which then contributes to robust cytotoxic anti-tumor immunity.

ATXN7L3B promotes hepatocellular carcinoma stemness and is downregulated by metformin.

Hepatocellular carcinoma (HCC) is the major cause of liver cancer-associated morality. Metformin, used for treating type 2 diabetes, has antitumor activity and reduces the risk of some diabetes-related tumors, such as liver and breast cancer. However, the mechanisms underlying metformin's effects in HCC remain unclear. To identify genes associated with metformin treatment in HCC, we conducted transcriptomic and proteomic analyses in HCC cells treated with or without metformin. We identified 41 differentially expressed genes upon metformin treatment. Among them, Ataxin 7 Like 3B (ATXN7L3B), which is a negative regulator of the Spt-Ada-Gcn5 acetyltransferase (SAGA) deubiquitinase (DUB) module and has relatively unknown functions in cancer, attracted our attention. We observed that metformin reduced ATXN7L3B level in HCC cells. ATXN7L3B expression was significantly negatively correlated with survival in liver cancer patients. We also demonstrated that ATXN7L3B promoted HCC stemness. Metformin treatment decreased ATXN7L3B-induced tumor-initiating ability in a HCC mouse model, implying that metformin may inhibit cancer stemness by downregulating ATXN7L3B. Our study supports the antitumor activity of metformin and its potential as an anticancer drug for HCC treatment.

MT4-MMP promotes invadopodia formation and cell motility in FaDu head and neck cancer cells.

Hypoxia-inducible factor-1α (HIF-1α) induces cancer metastasis. We previously demonstrated that HIF-1α-induced membrane-type 4 matrix metalloproteinase (MT4-MMP) is involved in hypoxia-mediated metastasis in head and neck squamous cell carcinoma (HNSCC). However, the functions and detailed mechanisms of MT4-MMP in cancer metastasis are not well understood. In this study, we investigated whether MT4-MMP regulates invadopodia formation or individual cell movement-both critical to cancer migration and invasion-in three-dimensional (3D) environments. By expressing MT4-MMP in the HNSCC cell line FaDu, we demonstrated that MT4-MMP increases invadopodia formation and gelatin degradation. Furthermore, the amoeboid-like cell movement on collagen gel was increased by MT4-MMP expression in FaDu cells. Mechanistically, MT4-MMP may induce invadopodia formation by binding with Tks5 and PDGFRα to result in Src activation and promote amoeboid-like movement by stimulating the small GTPases Rho and Cdc42. Altogether, our data indicate that MT4-MMP induces two crucial mechanisms of cancer dissemination, invadopodia formation and amoeboid movement, and elucidate the prometastatic role of MT4-MMP in hypoxia-mediated cancer metastasis.

Ninjurin1 enhances the basal motility and transendothelial migration of immune cells by inducing protrusive membrane dynamics.

Ninjurin1 is involved in the pathogenesis of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis, by mediating leukocyte extravasation, a process that depends on homotypic binding. However, the precise regulatory mechanisms of Ninjurin1 during inflammation are largely undefined. We therefore examined the pro-migratory function of Ninjurin1 and its regulatory mechanisms in macrophages. Interestingly, Ninjurin1-deficient bone marrow-derived macrophages exhibited reduced membrane protrusion formation and dynamics, resulting in the impairment of cell motility. Furthermore, exogenous Ninjurin1 was distributed at the membrane of filopodial structures in Raw264.7 macrophage cells. In Raw264.7 cells, RNA interference of Ninjurin1 reduced the number of filopodial projections, whereas overexpression of Ninjurin1 facilitated their formation and thus promoted cell motility. Ninjurin1-induced filopodial protrusion formation required the activation of Rac1. In Raw264.7 cells penetrating an MBEC4 endothelial cell monolayer, Ninjurin1 was localized to the membrane of protrusions and promoted their formation, suggesting that Ninjurin1-induced protrusive activity contributed to transendothelial migration. Taking these data together, we conclude that Ninjurin1 enhances macrophage motility and consequent extravasation of immune cells through the regulation of protrusive membrane dynamics. We expect these findings to provide insight into the understanding of immune responses mediated by Ninjurin1.

Ninjurin1 deficiency attenuates susceptibility of experimental autoimmune encephalomyelitis in mice.

Ninjurin1 is a homotypic adhesion molecule that contributes to leukocyte trafficking in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. However, in vivo gene deficiency animal studies have not yet been done. Here, we constructed Ninjurin1 knock-out (KO) mice and investigated the role of Ninjurin1 on leukocyte trafficking under inflammation conditions such as EAE and endotoxin-induced uveitis. Ninjurin1 KO mice attenuated EAE susceptibility by reducing leukocyte recruitment into the injury regions of the spinal cord and showed less adhesion of leukocytes on inflamed retinal vessels in endotoxin-induced uveitis mice. Moreover, the administration of a custom-made antibody (Ab26-37) targeting the Ninjurin1 binding domain ameliorated the EAE symptoms, showing the contribution of its adhesion activity to leukocyte trafficking. In addition, we addressed the transendothelial migration (TEM) activity of bone marrow-derived macrophages and Raw264.7 cells according to the expression level of Ninjurin1. TEM activity was decreased in Ninjurin1 KO bone marrow-derived macrophages and siNinj1 Raw264.7 cells. Consistent with this, GFP-tagged mNinj1-overexpressing Raw264.7 cells increased their TEM activity. Taken together, we have clarified the contribution of Ninjurin1 to leukocyte trafficking in vivo and delineated its direct functions to TEM, emphasizing Ninjurin1 as a beneficial therapeutic target against inflammatory diseases such as multiple sclerosis.

Growth trajectories of children born preterm and full term with low birth weight to preschool ages: A nationwide study.

CONTEXT: Preterm (PT) and full term with low birth weight (FT-LBW) children are at a high-risk of poor growth outcomes. OBJECTIVE: To investigate the growth trajectories of PT and FT-LBW children from birth to preschool ages. METHODS: This study included 1,150,508 infants (PT, 41,454; FT-LBW, 38,250) who underwent the first three rounds (4-6, 9-12, and 18-24 months) of the National Health Screening Program for Infants and Children (NHSPIC). Growth measurements were obtained from the NHSPIC database and converted into Z-scores. Growth data at 2, 4, and 6 years old were measured as outcome variables. The impact of being born small on poor growth outcomes was investigated using a generalized estimating equation and Cox proportional-hazards regression analysis. RESULTS: The median birth weights of the PT, FT-LBW, and full term (FT) groups were 2.3, 2.4, and 3.2 kg, respectively. The incidence of short stature (height Z-score < -2 standard deviation score [SDS]) and failure to thrive (FTT) (body mass index (BMI) Z-score < -2 SDS) was the highest in the FT-LBW group, followed by the PT and FT groups. At 4 years old, the incidence rates were 6.0% vs. 5.2% vs. 1.9% for short stature and 4.6% vs. 3.9% vs. 1.7% for FTT. The ß estimate of height outcome was lower in both the PT (-0.326 SDS) and FT-LBW (-0.456 SDS) groups. CONCLUSIONS: The FT-LBW group was consistently shorter and lighter throughout the preschool period than the PT group, highlighting the significance of growth monitoring in high-risk populations.

TESC associated with poor prognosis enhances cancer stemness and migratory properties in liver cancer.

Liver cancer stem cells (LCSCs) are responsible for recurrence, metastasis, and drug resistance in liver cancer. However, the genes responsible for inducing LCSCs have not been fully identified. Based on our previous study, we found that tescalcin (TESC), a calcium-binding EF hand protein that plays a crucial role in chromatin remodeling, transcriptional regulation, and epigenetic modifications, was up-regulated in LCSCs of spheroid cultures. By searching the Cancer Genome Atlas, International Cancer Genome Consortium, Human Protein Atlas, and Kaplan-Meier Plotter databases, we found that TESC expression was significantly elevated in liver cancer compared with that in normal liver tissue and was predictive of a decreased overall survival rate. Multivariate Cox analysis revealed TESC to be an independent prognostic factor for survival. High TESC expression was positively associated with cancer stem cell pathways, cancer stem cell surface markers, stemness transcription factors, epithelial-mesenchymal transition (EMT) factors, immune checkpoint proteins, and various cancer-related biological processes in liver cancer. Furthermore, TESC was implicated as promoting cancer stem cell properties through its influence on EMT. We demonstrated that TESC is a novel stemness-related gene that can serve as an independent prognostic factor for liver cancer.

PPIH as a poor prognostic factor increases cell proliferation and m6A RNA methylation in hepatocellular carcinoma.

RNA-binding proteins (RBPs) play a crucial role in the biological processes of liver hepatocellular carcinoma (LIHC). Peptidyl-prolyl cis-trans isomerase H (PPIH), an RBP, possesses prolyl isomerase activity and functions as a protein chaperone. The relationship between PPIH and LIHC has not yet been fully elucidated. This study elucidated potential mechanisms through which PPIH affects the prognosis of LIHC. Bioinformatics analysis and in vitro experiments revealed that PPIH expression was higher in LIHC tissues than in normal tissues. PPIH was identified as an independent prognostic factor, with high PPIH expression being associated with worse prognoses. Moreover, PPIH increased the m6A RNA methylation level and promoted cell proliferation by modulating DNA replication and the expression of cell cycle-related genes in LIHC cells. Bioinformatics analysis also revealed that PPIH expression increased immune cell infiltration and the expression of immune checkpoint proteins. Collectively, these findings indicate that PPIH might promote LIHC progression by enhancing the m6A RNA methylation level, increasing cell proliferation, and altering the tumor immune microenvironment. Our study demonstrates that PPIH, as a poor prognostic factor, may lead to LIHC malignancy through multiple pathways. Further in-depth research on this topic is warranted.

NAMPT-Driven M2 Polarization of Tumor-Associated Macrophages Leads to an Immunosuppressive Microenvironment in Colorectal Cancer.

Nicotinamide phosphoribosyltransferase (NAMPT) is a metabolic enzyme with key roles in inflammation. Previous studies have examined the consequences of its upregulated expression in cancer cells themselves, but studies are limited with respect to its role in the other cells within the tumor microenvironment (TME) during colorectal cancer (CRC) progression. Using single-cell RNA sequencing (scRNA-seq) data, it is founded that NAMPT is highly expressed in SPP1+ tumor-associated macrophages (TAMs), a unique subset of TAMs associated with immunosuppressive activity. A NAMPThigh gene signature in SPP1+ TAMs correlated with worse prognostic outcomes in CRC patients. The effect of Nampt deletion in the myeloid compartment of mice during CRC development is explored. NAMPT deficiency in macrophages resulted in HIF-1α destabilization, leading to reduction in M2-like TAM polarization. NAMPT deficiency caused significant decreases in the efferocytosis activity of macrophages, which enhanced STING signaling and the induction of type I IFN-response genes. Expression of these genes contributed to anti-tumoral immunity via potentiation of cytotoxic T cell activity in the TME. Overall, these findings suggest that NAMPT-initiated TAM-specific genes can be useful in predicting poor CRC patient outcomes; strategies aimed at targeting NAMPT may provide a promising therapeutic approach for building an immunostimulatory TME in CRC progression.

Association between smartphone usage and health outcomes of adolescents: A propensity analysis using the Korea youth risk behavior survey.

OBJECTIVES: We aimed to investigate the association between smartphone use and adverse behavioral health outcomes using nationwide Korea Youth Risk Behavior Web-based Survey data for 2017 and 2020. METHODS: The 2020 data (N = 54,809) were used to analyze the relationships between daily smartphone usage time (non-user, 0-2 h [hour], 2-4 h, 4-6 h, 6-8 h, and > 8 h), and adverse health outcomes (stress, sleep, depression, suicide, substance use, and smartphone overdependence). A 1:1 propensity score matching (PSM) was used to control for confounding variables. RESULTS: A total of 40,998 adolescents with < 4 h/day and > 4 h/day of usage were included. Adolescents' mean smartphone usage time in 2020 increased compared to that in 2017 (weighted % of > 2 h/day; 64.3% vs. 85.7%). The curvilinear relationships between smartphone usage time and adverse health outcomes were prominent after > 4 h/day. Adolescents using smartphones 2-4 h/day showed no increased adverse health outcomes compared to non-users, except for smartphone overdependence. Using a smartphone > 4 h/day was significantly associated with stress perception (1.16; 1.11-1.22), suicidal ideation (1.22; 1.13-1.31), and substance use (alcohol, 1.66; 1.57-1.75) after PSM. CONCLUSIONS: Our study demonstrated the curvilinear relationship between smartphone usage time and adverse health outcomes in adolescents. Our findings can help establish smartphone usage guidelines for adolescents.