EZH2-Mediated Epigenetic Suppression of GDF15 Predicts a Poor Prognosis and Regulates Cell Proliferation in Non-Small-Cell Lung Cancer

Characterizing the secretome of EGFR mutant lung adenocarcinoma

Background

Lung cancer is the leading cause of cancer related death worldwide, mainly due to the late stage of disease at the time of diagnosis. Non-invasive biomarkers are needed to supplement existing screening methods to enable earlier detection and increased patient survival. This is critical to EGFR-driven lung adenocarcinoma as it commonly occurs in individuals who have never smoked and do not qualify for current screening protocols.

Methods

In this study, we performed mass spectrometry analysis of the secretome of cultured lung cells representing different stages of mutant EGFR driven transformation, from normal to fully malignant. Identified secreted proteins specific to the malignant state were validated using orthogonal methods and their clinical activity assessed in lung adenocarcinoma patient cohorts.

Results

We quantified 1020 secreted proteins, which were compared for differential expression between stages of transformation. We validated differentially expressed proteins at the transcriptional level in clinical tumor specimens, association with patient survival, and absolute concentration to yield three biomarker candidates: MDK, GDF15, and SPINT2. These candidates were validated using ELISA and increased levels were associated with poor patient survival specifically in EGFR mutant lung adenocarcinoma patients.

Conclusions

Our study provides insight into changes in secreted proteins during EGFR driven lung adenocarcinoma transformation that may play a role in the processes that promote tumor progression. The specific candidates identified can harnessed for biomarker use to identify high risk individuals for early detection screening programs and disease management for this molecular subgroup of lung adenocarcinoma patients.

ELFN1-AS1 promotes GDF15-mediated immune escape of colorectal cancer from NK cells by facilitating GCN5 and SND1 association

The ability of colorectal cancer (CRC) cells to escape from natural killer (NK) cell immune surveillance leads to anti-tumor treatment failure. The long non-coding RNA (lncRNA) ELFN1-AS1 is aberrantly expressed in multiple tumors suggesting a role as an oncogene in cancer development. However, whether ELFN1-AS1 regulates immune surveillance in CRC is unclear. Here, we determined that ELFN1-AS1 enhanced the ability of CRC cells to escape from NK cell surveillance in vitro and in vivo. In addition, we confirmed that ELFN1-AS1 in CRC cells attenuated the activity of NK cell by down-regulating NKG2D and GZMB via the GDF15/JNK pathway. Furthermore, mechanistic investigations demonstrated that ELFN1-AS1 enhanced the interaction between the GCN5 and SND1 protein and this influenced H3k9ac enrichment at the GDF15 promotor to stimulate GDF15 production in CRC cells. Taken together, our findings indicate that ELFN1-AS1 in CRC cells suppresses NK cell cytotoxicity and ELFN1-AS1 is a potential therapeutic target for CRC.

Lysine-Specific Demethylase 1 Promises to Be a Novel Target in Cancer Drug Resistance: Therapeutic Implications

Chemotherapy, targeted therapy, and immunotherapy are effective against most tumors, but drug resistance remains a barrier to successful treatment. Lysine-specific demethylase 1 (LSD1), a member of histone demethylation modifications, can regulate invasion, metastasis, apoptosis, and immune escape of tumor cells, which are associated with tumorigenesis and tumor progression. Recent studies suggest that LSD1 ablation regulates resensitivity of tumor cells to anticarcinogens containing immune checkpoint inhibitors (ICIs) via multiple upstream and downstream pathways. In this review, we describe the recent findings about LSD1 biology and its role in the development and progression of cancer drug resistance. Further, we summarize LSD1 inhibitors that have a reversal or resensitive effect on drug resistance and discuss the possibility of targeting LSD1 in combination with other agents to surmount resistance.

The pharmacological and biological importance of EZH2 signaling in lung cancer

Up to 18% of cancer-related deaths worldwide are attributed to lung tumor and global burden of this type of cancer is ascending. Different factors are responsible for development of lung cancer such as smoking, environmental factors and genetic mutations. EZH2 is a vital protein with catalytic activity and belongs to PCR2 family. EZH2 has been implicated in regulating gene expression by binding to promoter of targets. The importance of EZH2 in lung cancer is discussed in current manuscript. Activation of EZH2 significantly elevates the proliferation rate of lung cancer. Furthermore, metastasis and associated molecular mechanisms including EMT undergo activation by EZH2 in enhancing the lung cancer progression. The response of lung cancer to therapy can be significantly diminished due to EZH2 upregulation. Since EZH2 increases tumor progression, anti-cancer agents suppressing its expression reduce malignancy. In spite of significant effort in understanding modulatory function of EZH2 on other pathways, it appears that EZH2 can be also regulated and controlled by other factors that are described in current review. Therefore, translating current findings to clinic can improve treatment and management of lung cancer patients.

Mitochondrial stress and mitokines in aging

Mitokines are signaling molecules that enable communication of local mitochondrial stress to other mitochondria in distant cells and tissues. Among those molecules are FGF21, GDF15 (both expressed in the nucleus) and several mitochondrial-derived peptides, including humanin. Their responsiveness to mitochondrial stress induces mitokine-signaling in response for example to exercise, following mitochondrial challenges in skeletal muscle. Such signaling is emerging as an important mediator of exercise-derived and dietary strategy-related molecular and systemic health benefits, including healthy aging. A compensatory increase in mitokine synthesis and secretion could preserve mitochondrial function and overall cellular vitality. Conversely, resistance against mitokine actions may also develop. Alterations of mitokine-levels, and therefore of mitokine-related inter-tissue cross talk, are associated with general aging processes and could influence the development of age-related chronic metabolic, cardiovascular and neurological diseases; whether these changes contribute to aging or represent "rescue factors" remains to be conclusively shown. The aim of the present review is to summarize the expanding knowledge on mitokines, the potential to modulate them by lifestyle and their involvement in aging and age-related diseases. We highlight the importance of well-balanced mitokine-levels, the preventive and therapeutic properties of maintaining mitokine homeostasis and sensitivity of mitokine signaling but also the risks arising from the dysregulation of mitokines. While reduced mitokine levels may impair inter-organ crosstalk, also excessive mitokine concentrations can have deleterious consequences and are associated with conditions such as cancer and heart failure. Preservation of healthy mitokine signaling levels can be achieved by regular exercise and is associated with an increased lifespan.

Plasma GDF15 levels associated with circulating immune cells predict the efficacy of PD-1/PD-L1 inhibitor treatment and prognosis in patients with advanced non-small cell lung cancer

PURPOSE

Although increased plasma growth differentiation factor-15 (GDF15) levels have been reported in patients with various cancers, the predictive role of PD-1/PD-L1 inhibitors in advanced cancers remains unknown. This study aimed to investigate GDF15 levels as a predictive marker in advanced non-small cell lung cancer (NSCLC) treated with PD-1/PD-L1 inhibitors and analyze their association with immune cell populations.

METHODS

This study included 87 patients with advanced NSCLC receiving anti-PD-1/PD-L1 inhibitors between March 2018 and May 2020. Blood samples were obtained immediately before and months after PD-1/PD-L1 inhibitor administration.

RESULTS

The objective response rate (ORR) was significantly higher in the low GDF15 than in the high GDF15 group (39.2% vs. 15.3%, P = 0.013). The median progression-free survival (PFS) was significantly longer in the low GDF15 than in the high GDF15 group (13.2 [95% CI 7.6-18.9] vs. 7.2 [95% CI 4.8-9.6] months, P = 0.048). Moreover, plasma GDF15 levels negatively correlated with PD-1⁺/CD8⁺ T cells (r = - 0.399, P = 0.003) and positively with PD-1⁺/Treg cells (r = 0.507, P < 0.001) and PD-1⁺Treg/CD4⁺ T cells (r = 0.439, P < 0.001). The ORR was significantly higher in the group with decreased GDF15 from baseline than in the increased GDF15 group (37.2% vs. 10.0%, P = 0.026). The median PFS was significantly longer in the decreased GDF15 group (14.8 [95% CI 10.4-19.2] vs. 5.9 [95% CI 2.8-9.0] months, P = 0.002). Plasma GDF15 levels were associated with PD-1⁺CD8⁺ T cells and PD-1⁺ Treg cells.

CONCLUSION

Plasma GDF15 could be a potential biomarker for predicting the efficacy and survival benefit of immunotherapy in advanced NSCLC.

Expression patterns of platinum resistance-related genes in lung adenocarcinoma and related clinical value models

The purpose of this study was to explore platinum resistance-related biomarkers and mechanisms in lung adenocarcinoma. Through the analysis of gene expression data of lung adenocarcinoma patients and normal patients from The Cancer Genome Atlas, Gene Expression Omnibus database, and A database of genes related to platinum resistance, platinum resistance genes in lung adenocarcinoma and platinum resistance-related differentially expressed genes were obtained. After screening by a statistical significance threshold, a total of 252 genes were defined as platinum resistance genes with significant differential expression, of which 161 were up-regulated and 91 were down-regulated. The enrichment results of up-regulated gene Gene Ontology (GO) showed that TOP3 entries related to biological processes (BP) were double-strand break repair, DNA recombination, DNA replication, the down-regulated gene GO enriches the TOP3 items about biological processes (BP) as a response to lipopolysaccharide, muscle cell proliferation, response to molecule of bacterial origin. Gene Set Enrichment Analysis showed that the top three were e2f targets, g2m checkpoint, and rgf beta signaling. A prognostic model based on non-negative matrix factorization classification showed the characteristics of high- and low-risk groups. The prognostic model established by least absolute shrinkage and selection operator regression and risk factor analysis showed that genes such as HOXB7, NT5E, and KRT18 were positively correlated with risk score. By analyzing the differences in m6A regulatory factors between high- and low-risk groups, it was found that FTO, GPM6A, METTL3, and YTHDC2 were higher in the low-risk group, while HNRNPA2B1, HNRNPC, TGF2BP1, IGF2BP2, IGF2BP3, and RBM15B were higher in the high-risk group. Immune infiltration and drug sensitivity analysis also showed the gene characteristics of the platinum-resistant population in lung adenocarcinoma. ceRNA analysis showed that has-miR-374a-5p and RP6-24A23.7 were lower in the tumor expression group, and that the survival of the low expression group was worse than that of the high expression group. In conclusion, the results of this study show that platinum resistance-related differentially expressed genes in lung adenocarcinoma are mainly concentrated in biological processes such as DNA recombination and response to lipopolysaccharide. The validation set proved that the high-risk group of our prognostic model had poor survival. M6A regulatory factor analysis, immune infiltration, and drug sensitivity analysis all showed differences between high and low-risk groups. ceRNA analysis showed that has-miR-374a-5p and RP6-24A23.7 could be protective factors. Further exploration of the potential impact of these genes on the risk and prognosis of drug-resistant patients with lung adenocarcinoma would provide theoretical support for future research.

Diltiazem inhibits breast cancer metastasis via mediating growth differentiation factor 15 and epithelial-mesenchymal transition

Migration and metastasis commonly happen to triple-negative breast cancer (TNBC) patients with advanced diseases. In many studies, it has been suggested that epithelial-mesenchymal transition (EMT) is one of the key mechanisms triggering cancer metastasis. Accumulating evidence has proven that calcium channel blockers mediate cell motility. Therefore, we attempt to investigate the effects of diltiazem, which has been selected from several FDA-approved clinical calcium channel blockers, on EMT in TNBC. By using both mouse and human TNBC cell lines, we found that diltiazem decreases colony formation and cell migration in breast cancer cells. The expression of epithelial markers such as E-cadherin and ZO-1 were increased dose-dependently by diltiazem, while mesenchymal markers such as Snail and Twist were decreased. In addition, we found that the expression of growth differentiation factor-15 (GDF-15) was also increased by diltiazem. Administering recombinant GDF-15 also reverses EMT, inhibits colony formation and migration in breast cancer cells. Moreover, treatment with diltiazem in tumor-bearing mice also decreases cancer metastasis and nodule formation, with more GDF-15 expression in diltiazem-treated mice than saline-treated mice, respectively. These findings suggest that diltiazem regulates EMT and cell motility through elevating GDF-15 expression in breast cancers in vitro and in vivo.

Lipidomic and Membrane Mechanical Signatures in Triple-Negative Breast Cancer: Scope for Membrane-Based Theranostics

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer associated with poor prognosis, higher grade, and a high rate of metastatic occurrence. Limited therapeutic interventions and the compounding issue of drug resistance in triple-negative breast cancer warrants the discovery of novel therapeutic targets and diagnostic modules. To this view, in addition to proteins, lipids also regulate cellular functions via the formation of membranes that modulate membrane protein function, diffusion, and their localization; thus, orchestrating signaling hot spots enriched in specific lipids/proteins on cell membranes. Lipid deregulation in cancer leads to reprogramming of the membrane dynamics and functions impacting cell proliferation, metabolism, and metastasis, providing exciting starting points for developing lipid-based approaches for treating TNBC. In this review, we provide a detailed account of specific lipidic changes in breast cancer, link the altered lipidome with membrane structure and mechanical properties, and describe how these are linked to subsequent downstream functions implicit in cancer progression, metastasis, and chemoresistance. At the fundamental level, we discuss how the lipid-centric findings in TNBC are providing cues for developing lipid-inspired theranostic strategies while bridging existing gaps in our understanding of the functional involvement of lipid membranes in cancer.

Estradiol-mediated inhibition of DNMT1 decreases p53 expression to induce M2-macrophage polarization in lung cancer progression

Previous studies indicate that estrogen positively regulates lung cancer progression. Understanding the reasons will be beneficial for treating women with lung cancer in the future. In this study, we found that tumor formation was more significant in female EGFR^L858R mice than in male mice. P53 expression levels were downregulated in the estradiol (E2)-treated lung cancer cells, female mice with EGFR^L858R-induced lung cancer mice, and premenopausal women with lung cancer. E2 increased DNA methyltransferase 1 (DNMT1) expression to enhance methylation in the TP53 promoter, which led to the downregulation of p53. Overexpression of GFP-p53 decreased DNMT1 expression in lung cancer cells. TP53 knockout in mice with EGFR^L858R-induced lung cancer not only changed gene expression in cancer cells but also increased the polarization of M2 macrophages by increasing C–C motif chemokine ligand 5 (CCL5) expression and decreasing growth differentiation factor 15 (GDF15) expression. The TP53 mutation rate was increased in females with late-stage but not early-stage lung cancer compared to males with lung cancer. In conclusion, E2-induced DNMT1 and p53 expression were negatively regulated each other in females with lung cancer, which not only affected cancer cells but also modulated the tumor-associated microenvironment, ultimately leading to a poor prognosis.

Ionizing Radiation-Induced GDF15 Promotes Angiogenesis in Human Glioblastoma Models by Promoting VEGFA Expression Through p-MAPK1/SP1 Signaling

Glioblastoma multiforme (GBM), the most aggressive cancer type that has a poor prognosis, is characterized by enhanced and aberrant angiogenesis. In addition to surgical resection and chemotherapy, radiotherapy is commonly used to treat GBM. However, radiation-induced angiogenesis in GBM remains unexplored. This study examined the role of radiation-induced growth/differentiation factor-15 (GDF15) in regulating tumor angiogenesis by promoting intercellular cross-talk between brain endothelial cells (ECs) and glioblastoma cells. Radiation promoted GDF15 secretion from human brain microvascular endothelial cells (HBMVECs). Subsequently, GDF15 activated the transcriptional promoter VEGFA in the human glioblastoma cell line U373 through p-MAPK1/SP1 signaling. Upregulation of vascular endothelial growth factor (VEGF) expression in U373 cells resulted in the activation of angiogenic activity in HBMVECs via KDR phosphorylation. Wound healing, tube formation, and invasion assay results revealed that the conditioned medium of recombinant human GDF15 (rhGDF15)-stimulated U373 cell cultures promoted the angiogenic activity of HBMVECs. In the HBMVEC-U373 cell co-culture, GDF15 knockdown mitigated radiation-induced VEGFA upregulation in U373 cells and enhanced angiogenic activity of HBMVECs. Moreover, injecting rhGDF15-stimulated U373 cells into orthotopic brain tumors in mice promoted angiogenesis in the tumors. Thus, radiation-induced GDF15 is essential for the cross-talk between ECs and GBM cells and promotes angiogenesis. These findings indicate that GDF15 is a putative therapeutic target for patients with GBM undergoing radio-chemotherapy.

Establishment of a ferroptosis-related gene signature for prognosis in lung adenocarcinoma patients

Objective

Lung cancer is the most common malignancy worldwide and exhibits both high morbidity and mortality. In recent years, scientists have made substantial breakthroughs in the early diagnosis and treatment of lung adenocarcinoma (LUAD), however, patient prognosis still shows vast individual differences. In this study, bioinformatics methods were used to identify and analyze ferroptosis-related genes to establish an effective signature for predicting prognosis in LUAD patients.

Methods

The gene expression profiles of LUAD patients with complete clinical and follow-up information were downloaded from two public databases, univariate Cox regression and multivariate Cox regression analysis were used to obtain ferroptosis-related genes for constructing the prognos tic risk model, AUC and calibration plot were used to evaluate the predictive accuracy of the FRGS and nomogram.

Results

A total of 74 ferroptosis-related differentially expressed genes (DEGs) were identi fied between LUAD and normal tissues from The Cancer Genome Atlas (TCGA) database. A five-gene panel for prediction of LUAD prognosis was established by multivariate regression and was verified using the GSE68465 cohort from the Gene Expression Omnibus (GEO) database. Patients were divided into two different risk groups according to the median risk score of the five genes. Based on Kaplan-Meier (KM) analysi, the OS rate of the high-risk group was markedly worse than that of the low-risk group. We also found that risk score was an independent prognostic indicator. The receiver operating characteristic ROC curve showed that the proposed model had good prediction ability. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses indicated that risk score was prominently enriched in ferroptosis processes. Moreover, at the score of immune-associated gene sets, significant differences were found between the two risk groups.

Conclusions

This study demonstrated that ferroptosis-related gene signatures can be used as a potential predictor for the prognosis of LUAD, thus providing a novel strategy for individualized treatment in LUAD patients.

Development of potent dimeric inhibitors of GAS41 YEATS domain

GAS41 is an emerging oncogene overexpressed and implicated in multiple cancers, including non-small cell lung cancer (NSCLC). GAS41 is a dimeric protein that contains the YEATS domain, which is involved in the recognition of lysine-acylated histones. Here, we report the development of GAS41 YEATS inhibitors by employing a fragment-based screening approach. These inhibitors bind to GAS41 YEATS domain in a channel constituting a recognition site for acylated lysine on histone proteins. To enhance inhibitory activity, we developed a dimeric analog with nanomolar activity that blocks interactions of GAS41 with acetylated histone H3. Our lead compound engages GAS41 in cells, blocks proliferation of NSCLC cells, and modulates expression of GAS41-dependent genes, validating on-target mechanism of action. This study demonstrates that disruption of GAS41 protein-protein interactions may represent an attractive approach to target lung cancer cells. This work exemplifies the use of bivalent inhibitors as a general strategy to block challenging protein-protein interactions.

Growth/Differentiation Factor-15 (GDF-15): From Biomarker to Novel Targetable Immune Checkpoint

Growth/differentiation factor-15 (GDF-15), also named macrophage inhibitory cytokine-1, is a divergent member of the transforming growth factor β superfamily. While physiological expression is barely detectable in most somatic tissues in humans, GDF-15 is abundant in placenta. Elsewhere, GDF-15 is often induced under stress conditions, seemingly to maintain cell and tissue homeostasis; however, a moderate increase in GDF-15 blood levels is observed with age. Highly elevated GDF-15 levels are mostly linked to pathological conditions including inflammation, myocardial ischemia, and notably cancer. GDF-15 has thus been widely explored as a biomarker for disease prognosis. Mechanistically, induction of anorexia via the brainstem-restricted GDF-15 receptor GFRAL (glial cell-derived neurotrophic factor [GDNF] family receptor α-like) is well-documented. GDF-15 and GFRAL have thus become attractive targets for metabolic intervention. Still, several GDF-15 mediated effects (including its physiological role in pregnancy) are difficult to explain via the described pathway. Hence, there is a clear need to better understand non-metabolic effects of GDF-15. With particular emphasis on its immunomodulatory potential this review discusses the roles of GDF-15 in pregnancy and in pathological conditions including myocardial infarction, autoimmune disease, and specifically cancer. Importantly, the strong predictive value of GDF-15 as biomarker may plausibly be linked to its immune-regulatory function. The described associations and mechanistic data support the hypothesis that GDF-15 acts as immune checkpoint and is thus an emerging target for cancer immunotherapy.

Role of the mitochondrial stress response in human cancer progression

IMPACT STATEMENT

Dysregulated mitochondria often occurred in cancers. Mitochondrial dysfunction might contribute to cancer progression. We reviewed several mitochondrial stresses in cancers. Mitochondrial stress responses might contribute to cancer progression. Several mitochondrion-derived molecules (ROS, Ca2+, oncometabolites, exported mtDNA, mitochondrial double-stranded RNA, humanin, and MOTS-c), integrated stress response, and mitochondrial unfolded protein response act as retrograde signaling pathways and might be critical in the development and progression of cancer. Targeting these mitochondrial stress responses may be an important strategy for cancer treatment.

Dysregulation of SPRR3/miR-876-3p Axis Contributes to Tumorigenesis in Non-Small-Cell Lung Cancer

Background

SPRR3, also known as esophagin, has been shown to be involved in the initiation and progression of numerous types of tumor. However, the biological function of SPRR3 that contributes to non-small-cell lung cancer (NSCLC) growth and migration is largely unknown.

Methods

The expression of SPRR3 and its association with EZH2 and miR-876-3p in NSCLC cells were determined by real-time PCR. Protein levels were measured by immunohistochemistry (IHC) and Western blot. Cell functions were studied by CCK-8, transwell assay, flow cytometry and dual-luciferase reporter assay. The effect of SPRR3 on tumor growth in vivo was evaluated in patient-derived xenograft (PDX) models.

Results

SPRR3 was up-regulated in most NSCLC cell lines and clinical tissues. Also, the correlation between SPRR3 expression and clinical features was significant. Functional studies confirmed that SPRR3 modulates cell proliferation, invasion and cell apoptosis in NSCLC via regulating EZH2, which is a well-known oncogene in NSCLC. Furthermore, SPRR3 was found to be a direct target of miR-876-3p that also plays a suppressor role in NSCLC.

Conclusion

These findings indicated that miR-876-3p/SPRR3/EZH2 signaling cascade exerts important roles in the regulation of NSCLC, suggesting that this pathway can serve as a potential therapeutic target in NSCLC.

Long noncoding RNA HAS2-AS1 accelerates non-small cell lung cancer chemotherapy resistance by targeting LSD1/EphB3 pathway

The essential roles of long noncoding RNA (lncRNA) have been identified by emerging literature in the non-small cell lung cancer (NSCLC). However, the role of lncRNA hyaluronan synthase 2 antisense 1 (HAS2-AS1) in the NSCLC tumorigenesis is not clear. Here, we investigate the role and mechanism of HAS2-AS1 in the NSCLC tumorigenesis. In the NSCLC tissue and cells, HAS2-AS1 was found to be up-regulated, which, in turn, indicated the poor prognosis of NSCLC patients. Functional experiments illustrated that HAS2-AS1 promoted the proliferation, invasion and gefitinib chemotherapy resistance of NSCLC cells. In vivo, HAS2-AS1 knockdown suppressed the tumor growth. Mechanically, HAS2-AS1 recruited the lysine-specific demethylase 1 (LSD1) to the EphB3 promoter region to inhibit its transcription. In conclusion, this finding elucidates the essential roles of HAS2-AS1 in the NSCLC tumorigenesis, providing a possible treatment strategy for the NSCLC.

N6-methyladenosine ALKBH5 promotes non-small cell lung cancer progress by regulating TIMP3 stability

Mounting evidence demonstrates that N⁶-methyladenosine (m⁶A) play critical roles of m⁶A in the epigenetic regulation, especially for human cancer. The m⁶A modification is installed by methyltransferase and erased demethylases, leading to the significant modification for gene expression and cell fate. Here, we investigated the biological roles and mechanism of demethylase alkylation repair homolog protein 5 (ALKBH5) in the non-small cell lung cancer (NSCLC). Results revealed that ALKBH5 was ectopically up-regulated in the NSCLC tissue and cells, and closely correlated with the poor prognosis. Functionally, ALKBH5 promoted the proliferation and reduced apoptosis of NSCLC cells in vitro, and knockdown of ALKBH5 repressed the tumor growth in vivo. Mechanistically, RNA immunoprecipitation sequencing (RIP-Seq) revealed that ALKBH5 targeted the TIMP3. Moreover, ALKBH5 repressed TIMP3 mRNA stability and protein production. In conclusion, the present research confirmed the ALKBH5/TIMP3 pathway in the NSCLC oncogenesis progress, providing a novel insight for the epitranscriptome and potential therapeutic target for NSCLC.

Selective Liver Estrogen Receptor α Modulation Prevents Steatosis, Diabetes, and Obesity Through the Anorectic Growth Differentiation Factor 15 Hepatokine in Mice

Hepatocyte estrogen receptor α (ERα) was recently recognized as a relevant molecular target for nonalcoholic fatty liver disease (NAFLD) prevention. The present study defined to what extent hepatocyte ERα could be involved in preserving metabolic homeostasis in response to a full (17β-estradiol [E2]) or selective (selective estrogen receptor modulator [SERM]) activation. Ovariectomized mice harboring a hepatocyte-specific ERα deletion (LERKO mice) and their wild-type (WT) littermates were fed a high-fat diet (HFD) and concomitantly treated with E2, tamoxifen (TAM; the most used SERM), or vehicle. As expected, both E2 and TAM prevented all HFD-induced metabolic disorders in WT mice, and their protective effects against steatosis were abolished in LERKO mice. However, while E2 still prevented obesity and glucose intolerance in LERKO mice, hepatocyte ERα deletion also abrogated TAM-mediated control of food intake as well as its beneficial actions on adiposity, insulin sensitivity, and glucose homeostasis, suggesting a whole-body protective role for liver-derived circulating factors. Moreover, unlike E2, TAM induced a rise in plasma concentration of the anorectic hepatokine growth differentiation factor 15 (Gdf15) through a transcriptional mechanism dependent on hepatocyte ERα activation. Accordingly, ERα was associated with specific binding sites in the Gdf15 regulatory region in hepatocytes from TAM-treated mice but not under E2 treatment due to specific epigenetic modifications. Finally, all the protective effects of TAM were abolished in HFD-fed GDF15-knockout mice. Conclusion: We identified the selective modulation of hepatocyte ERα as a pharmacologic strategy to induce sufficient anorectic hepatokine Gdf15 to prevent experimental obesity, type 2 diabetes, and NAFLD.

Growth and differentiation factor 15 regulates PD-L1 expression in glioblastoma

Background: Gliomablastoma multiforme (GBM) is the most fatal form of all brain cancers in human with no successful treatment available. Programmed death-ligand 1 (PD-L1) is a coinhibitory ligand predominantly expressed by tumor cells. Growth differentiation factors (GDFs) are a subfamily of proteins belonging to the transforming growth factor beta superfamily that have functions predominantly in tissue development and cancer.

Purpose: To investigat the expression of GDFs in GBMs, and explored the potential regulatory role of GDFs on PD-L1 expression in GBMs.

Methods: GEO2R program were analyzed for the mRNA expression data of GDFs in GSE4290 dataset. Analysis of TCGA GBM datasets were further determined the relationship between GDFs and PD-L1. Western blot Western blot was used to detect the expression of PD-L1 in GBM cell lines.

Results: GDFs displayed differential patterns of expression with GDF15 and myostatin (MSTN) highly enriched in GBM tissues. We also identified GDF15 as a novel regulator that induces PD-L1 expression in GBM cells. Consistently, GDF15 expression correlated with PD-L1 in TCGA GBM dataset. Further, GDF15 enhanced PD-L1 expression via Smad2/3 pathway in GBM cell line U87, U251 and SHG44, which was inhibited by Smad2/3 inhibitor SIS3. Knockdown of GDF15 attenuated Smad2/3 signaling and reduced PD-L1 expression in A172 and GIC6 glioma cells.

Conclusion: GDF15 might be a novel regulator of PD-L1 expression in GBMs; targeting GDF15/PD-L1 pathway might be a promising therapeutic approach for GBM patients.

Growth differentiation factor 15 (GDF15): A survival protein with therapeutic potential in metabolic diseases

Growth Differentiation Factor 15 (GDF15), also known as NSAID activated gene-1 (NAG-1), is associated with a large number of biological processes and diseases, including cancer and obesity. GDF15 is synthesized as pro-GDF15, is dimerized, and is cleaved and secreted into the circulation as a mature dimer GDF15. Both the intracellular GDF15 and the circulating mature GDF15 are implicated in biological processes, such as energy homeostasis and body weight regulation. Although there have been many studies on GDF15, GFRAL, a member of the glial-derived neurotropic factor receptor α family, has only been recently identified as a receptor for mature GDF15. In this review, we focused on cancer and energy homeostasis along with obesity and body weight, and the effect of the identification of the GDF15 receptor in these investigations. In addition, the therapeutic potential of GDF15 as a pharmacological agent in obesity and other metabolic diseases was discussed.