Targeting Smurf1 to block PDK1-Akt signaling in KRAS-mutated colorectal cancer.

The phosphoinositide 3-kinase (PI3K)-Akt axis is one of the most frequently activated pathways and is demonstrated as a therapeutic target in Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutated colorectal cancer (CRC). Targeting the PI3K-Akt pathway has been a challenging undertaking through the decades. Here we unveiled an essential role of E3 ligase SMAD ubiquitylation regulatory factor 1 (Smurf1)-mediated phosphoinositide-dependent protein kinase 1 (PDK1) neddylation in PI3K-Akt signaling and tumorigenesis. Upon growth factor stimulation, Smurf1 immediately triggers PDK1 neddylation and the poly-neural precursor cell expressed developmentally downregulated protein 8 (poly-Nedd8) chains recruit methyltransferase SET domain bifurcated histone lysine methyltransferase 1 (SETDB1). The cytoplasmic complex of PDK1 assembled with Smurf1 and SETDB1 (cCOMPASS) consisting of PDK1, Smurf1 and SETDB1 directs Akt membrane attachment and T308 phosphorylation. Smurf1 deficiency dramatically reduces CRC tumorigenesis in a genetic mouse model. Furthermore, we developed a highly selective Smurf1 degrader, Smurf1-antagonizing repressor of tumor 1, which exhibits efficient PDK1-Akt blockade and potent tumor suppression alone or combined with PDK1 inhibitor in KRAS-mutated CRC. The findings presented here unveil previously unrecognized roles of PDK1 neddylation and offer a potential strategy for targeting the PI3K-Akt pathway and KRAS mutant cancer therapy.

Advances in immune regulation of the G protein-coupled estrogen receptor.

Estrogen and related receptors have been shown to have a significant impact on human development, reproduction, metabolism and immune regulation and to play a critical role in tumor development and treatment. Traditionally, the nuclear estrogen receptors (nERs) ERα and ERß have been thought to be involved in mediating the estrogenic effects. However, our group and others have previously demonstrated that the G protein-coupled estrogen receptor (GPER) is the third independent ER, and estrogen signaling mediated by GPER is known to play an important role in normal physiology and a variety of abnormal diseases. Interestingly, recent studies have progressively revealed GPER involvement in the maintenance of the normal immune system, abnormal immune diseases, and inflammatory lesions, which may be of significant clinical value primarily in the immunotherapy of tumors. In this article, we review current advances in GPER-related immunomodulators and provide a theoretical basis and potential clinical targets to ameliorate immune-related diseases and immunotherapy for tumors.

YB-1 Targeted by miR-509-3-5p Affects Migration and Invasion of Triple­Negative Breast Cancer by Regulating Cellular Epithelial­Mesenchymal Transition.

The epithelial-mesenchymal transition (EMT) process is closely linked to metastasis of breast cancer. This article elucidates the role of Y-box binding protein-1 (YB-1) on the migration and invasion of triple-negative breast cancer (TNBC) cells by regulating EMT, and the related mechanism. The expression data of YB-1 and miR-509-3-5p in TNBC samples and normal samples were downloaded from the GEO database. The proliferation, migration, invasion, and EMT of TNBC cells were detected by CCK-8 assay, colony formation assay, wound-healing assay, transwell assay, and immunoblotting analyses. The targeted binding of YB-1 and miR-509-3-5p was validated by luciferase reporter experiment. A xenograft mouse model was constructed to investigate the influence of the miR-509-3-5p/YB-1 axis on TNBC tumor growth in vivo. YB-1 was overexpressed, while miR-509-3-5p was underexpressed in TNBC tumor tissues and various cell lines. Silencing YB-1 depressed cell viability, proliferation, motility, and EMT in vitro, and miR-509-3-5p upregulation exerted the same effects. YB-1 was targeted by miR-509-3-5p. The suppressive effects on the phenotypes of TNBC cells caused by overexpressed miR-509-3-5p were attenuated by YB-1 upregulation. In addition, miR-509-3-5p overexpression restrained TNBC tumor growth and downregulated the YB-1-mediated EMT process in vivo. YB-1 targeted by miR-509-3-5p affects motility of TNBC cells by regulating cellular EMT.

Whole-transcriptome defines novel glucose metabolic subtypes in colorectal cancer.

Colorectal cancer (CRC) is the most prevalent malignancy of the digestive system. Glucose metabolism plays a crucial role in CRC development. However, the heterogeneity of glucose metabolic patterns in CRC is not well characterized. Here, we classified CRC into specific glucose metabolic subtypes and identified the key regulators. 2228 carbohydrate metabolism-related genes were screened out from the GeneCards database, 202 of them were identified as prognosis genes in the TCGA database. Based on the expression patterns of the 202 genes, three metabolic subtypes were obtained by the non-negative matrix factorization clustering method. The C1 subtype had the worst survival outcome and was characterized with higher immune cell infiltration and more activation in extracellular matrix pathways than the other two subtypes. The C2 subtype was the most prevalent in CRC and was characterized by low immune cell infiltration. The C3 subtype had the smallest number of individuals and had a better prognosis, with higher levels of NRF2 and TP53 pathway expression. Secreted frizzled-related protein 2 (SFRP2) and thrombospondin-2 (THBS2) were confirmed as biomarkers for the C1 subtype. Their expression levels were elevated in high glucose condition, while their knockdown inhibited migration and invasion of HCT 116 cells. The analysis of therapeutic potential found that the C1 subtype was more sensitive to immune and PI3K-Akt pathway inhibitors than the other subtypes. To sum up, this study revealed a novel glucose-related CRC subtype, characterized by SFRP2 and THBS2, with poor prognosis but possible therapeutic benefits from immune and targeted therapies.

Electrocatalytic Interconversions of CO2 and Formate on a Versatile Iron-Thiolate Platform.

Exploring bidirectional CO2/HCO2- catalysis holds significant potential in constructing integrated (photo)electrochemical formate fuel cells for energy storage and applications. Herein, we report selective CO2/HCO2- electrochemical interconversion by exploiting the flexible coordination modes and rich redox properties of a versatile iron-thiolate platform, Cp*Fe(II)L (L = 1,2-Ph2PC6H4S-). Upon oxidation, this iron complex undergoes formate binding to generate a diferric formate complex, [(L-)2Fe(III)(µ-HCO2)Fe(III)]+, which exhibits remarkable electrocatalytic performance for the HCO2--to-CO2 transformation with a maximum turnover frequency (TOFmax) ∼103 s-1 and a Faraday efficiency (FE) ∼92(±4)%. Conversely, this iron system also allows for reduction at -1.85 V (vs Fc+/0) and exhibits an impressive FE ∼93 (±3)% for the CO2-to-HCO2- conversion. Mechanism studies revealed that the HCO2--to-CO2 electrocatalysis passes through dicationic [(L2)-•Fe(III)(µ-HCO2)Fe(III)]2+ generated by unconventional oxidation of the diferric formate species taking place at ligand L, while the CO2-to-HCO2- reduction involves a critical intermediate of [Fe(II)-H]- that was independently synthesized and structurally characterized.

Patients with metastatic renal cell carcinoma who receive immune-targeted therapy may derive survival benefit from nephrectomy.

BACKGROUND: Nephrectomy, whether in the era of cytokine therapy or targeted therapy, has an important role in the treatment of metastatic renal cell carcinoma. With the advent of immunotherapy, immunotherapy combined with targeted therapy has become the mainstream of systemic therapy, but the role of nephrectomy in metastatic renal cell carcinoma is unclear. In this study, we retrospectively analyzed the impact of nephrectomy on survival in patients with metastatic renal cell carcinoma who received immune-targeted therapy. METHODS: Patients with metastatic renal cell carcinoma who received immune-targeted therapy at three centers between May 17, 2019 and August 1, 2022 were collected, who were divided into two groups based on whether nephrectomy was performed or not. Survival, response rate and adverse event were compared between the two groups. The primary end point was progression free survival, Subgroup analysis and univariate and multivariable prognostic analyses were also assessed. RESULTS: With a median follow-up time of 29.3 months (95% CI 28.5-30.2), 165 patients were recruited and divided into two groups based on whether they underwent nephrectomy or not. There were 68 patients in the non-nephrectomy group, 97 in the nephrectomy group. Compared to patients treated with immune-targeted therapy, patients treated with immune-targeted therapy plus nephrectomy were able to achieve survival benefits, with a median PFS of 10.8 months (95% CI 8.3-13.3) and 14.4 months (95% CI 12.6-16.2), respectively, as well as an HR of 0.476 (95% CI 0.323-0.701, p = 0.0002). The 12-month and 18-month PFS rates were 30.9% versus 60.8% and 7.4% versus 25.8%, respectively. The objective response rate (ORR) was 52.9% and 60.8%, respectively, in the non-nephrectomy and nephrectomy groups (p = 0.313), and the disease control rate (DCR) was 75% and 83.5%, respectively (p = 0.179). The most common adverse events related to treatment were hypothyroidism, immune-related pneumonitis and rash. Multivariate analysis showed that primary tumor nephrectomy prior to immune-targeted therapy, clear cell renal carcinoma and oligo metastasis were independent prognostic factors. CONCLUSIONS: Nephrectomy may provide PFS benefit with tolerable safety for patients with metastatic renal cell carcinoma who receive immune-targeted therapy. In multivariate analysis, nephrectomy, clear cell carcinoma, and oligo-organ metastasis were found to be favorable independent prognostic factors.

YB-1 Expression Is Associated with Lymph Node Metastasis and Drug Resistance to Adriamycin in Breast Cancer.

Background: Breast cancer (BC) is the most common malignant tumor among females. Although there are multiple treatments for breast cancer, many patients still face the dilemma of drug resistance after multiline treatment. It would be greatly helpful for clinical work to identify additional and improved prognostic predictors. Y-box binding protein-1 (YB-1) is a member of the cold shock protein family, and patients with overexpression of YB-1 have a worse prognosis. Methods: This study collected 48 specimens from 48 patients with breast cancer and analyzed the clinicopathological characteristics of the patients. Immunohistochemistry, immunofluorescence, cell viability analysis, tumor spheroid formation and cell morphology, cell invasion, cycle analysis, qRT-PCR, Western blot, and tumorigenicity in BALB/c nude mice were performed to verify the results. Results: We found that patients with overexpression of YB-1 were related to lymph node metastasis and the patients' age tended to be young. Because of the short follow-up time, a survival analysis could not be performed. Based on the results of in vitro and in vivo experiments, this study indicated that breast cancer cells with overexpression of YB-1 had stronger proliferation, migration, and invasion abilities than cells with low expression of YB-1. Compared with cells with low expression of YB-1, the proliferation, migration, and invasion abilities of YB-1 overexpressed cells were not significantly affected by adriamycin. Conclusion: This suggested that breast cancer cells with overexpression of YB-1 were resistant to adriamycin. Therefore, YB-1 is associated with lymph node metastasis of breast cancer cell. YB-1 could be a prognostic, predictive factor and a novel therapeutic target of BC.

Hepatic artery intervention combined with immune-targeted therapy is superior to sequential therapy in BCLC-C hepatocellular carcinoma.

BACKGROUND: Hepatic artery intervention combined with immunotarget therapy exerts excellent disease control and prolongs survival. However, the arrangement of hepatic artery intervention and systemic therapy confuses clinical decisions. METHODS: A two-center, retrospective clinical study was approved by the Institutional Ethics Committee. From December 2018 to February 2022, patients with Barcelona Clinic Liver Cancer stage C (BCLC-C) hepatocellular carcinoma (HCC) who received targeted therapy plus PD-1 inhibitors with or without hepatic artery intervention were included. According to the treatment mode, the patients were assigned to three groups: initial hepatic artery intervention combined with immunotarget therapy, immunotarget therapy sequential hepatic artery interventional therapy, and immunotarget therapy only. The survival, response, and adverse events were compared among the three groups. Subgroup analysis and univariate and multivariate prognostic analyses were also evaluated. RESULTS: The median follow-up time was 18.3 months (95% CI 16.7 to 20.0 months). A total of 163 patients with BCLC-C stage HCC were assigned to three groups: initial hepatic artery intervention plus PD-1 inhibitors plus targeted therapy (HPT, n = 66), PD-1 inhibitors plus targeted therapy followed by hepatic artery intervention (PTH, n = 56) and PD-1 inhibitors plus targeted therapy (PT, n = 41). The median progression-free survival was 8.37 months (95% CI 6.35-10.39) with HPT versus 5.3 months (95% CI 3.48-7.12) with PTH versus 6.33 months (95% CI 3.75-8.92) with PT. The progression-free survival of the HPT group was better than that of the PTH group (HR 0.66, 95% CI 0.45-0.97, p = 0.027) and PT group (HR 0.60, 95% CI 0.39-0.92, p = 0.01). The median overall survival was 14.6 months (95% CI 10.6-18.7) with HPT, 10.0 months (95% CI 8.2-11.8) with PTH and 11.3 months (95% CI 8.3-14.3) with PT. The 1-year overall survival (OS) rates in the HPT, PTH and PT groups were 50%, 33.9%, and 34.1%, respectively. Overall survival was significantly longer in the HTP group than in the PT group (HR 0.60, 95% CI 0.361-0.996, p = 0.032). Compared with the PTH group, the overall survival of the HTP group had a prolonged survival trend (HR 0.66, 95% CI 0.416-1.032, p = 0.059). All treatment modalities were deemed equally safe. Multivariate analysis suggested that the mode of treatment, albumin level, Child‒Pugh grade and hepatectomy history were independent prognostic factors for BCLC-C HCC patients. CONCLUSIONS: Initial hepatic artery intervention combined with immunotarget therapy gained survival benefits with tolerable side effects compared with immunotarget sequential hepatic artery intervention and immunotarget therapy alone. Multivariate analysis suggested that liver reserve function was closely correlated with prognosis.

Clinicopathological characteristics, survival outcome and prognostic factors of very young gastric cancer.

To explore the clinicopathological characteristics, survival outcomes, and prognosis of very young gastric cancer (GC). From January 1, 2011 to January 1, 2021, GC patients under 30 years old treated in three tertiary hospitals were enrolled. Clinicopathological characteristics were summarized, prognostic factors and survival outcomes including overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS) were retrospectively analyzed. One hundred patients were finally included, with a median age of 23 years.73 (73.0%) were female. Most patients had initial symptoms of abdominal pain (66.0%). The most common tumor locations were gastric antrum (38.0%) and gastric body (37.0%). The main histological types were diffuse (81.0%) and poorly differentiated (91.0%). Most patients presented with stage III-IV disease (82.0%) at diagnosis and the common sites of metastasis were ovary (39.5%) and peritoneum (27.6%). The mOS of the whole group was 23.3 months (95% CI 17.2-29.4). Moreover, the mOS of patients at stage I-II was not reached. The mOS of patients at stage III and stage IV was 40.6 months (95% CI 10.2-70.9) and 10.3 months (95% CI 8.9-11.6), respectively. The mDFS of stage I-III patients was 28.5 months (95% CI 14.7-42.3), and the mPFS of the metastatic patients was 4.5 months (95% CI 4.0-5.0). TNM stage (P = 0.005) and radical surgery (P = 0.001) were independent prognostic factors of overall survival. The very young GC were predominantly female, diffuse type, and advanced diagnosis. TNM stage and radical surgery were independent prognosis factors for overall survival.

Valproic Acid Inhibits Peripheral T Cell Lymphoma Cells Behaviors via Restraining PI3K/AKT Pathway.

Objective: Alproic acid (VPA) is a clinic antiepileptic drug. Antitumor role of VPA has been studied. The aim of this study was to clarify the treatment effect and potential mechanism of VPA on peripheral T cell lymphomas (PTCLs). Materials and Methods: Hut 78 cells were obtained from the Shanghai Cell Bank, Chinese Academy of Sciences, and randomly divided into six groups: control, VPA (8 mM), empty vector (NC), miR-3196 mimics, miR-3196 inhibitor, and VPA + miR-3196 mimics groups. CCK-8 assay was performed to clarify the regulative role of VPA on cell proliferation. Flow cytometry was applied to determine the apoptotic rate and ROS levels. miR-3196 was tested by RT-qPCR. Western blot was used to test the level of p-PI3K and p-AKT. Biochemical experiments were used to detect changes in the content of ATP, lactate level, and glucose content. Electron microscopy was used to show the structure of mitochondria in Hut 78 cells. Results: VPA greatly promoted the expression of miR-3196 and inhibited cell proliferation in a dose-dependent manner. Compared with the NC group, the cell apoptosis rate, Bax and cleaved-caspase-3 expression, lactate level, ROS expression, and glucose content in the VPA group were significantly increased (P < 0.05), and cell proliferation, ATP production, and the expression of Bcl-2, p-PI3K and p-AKT was decreased significantly (P < 0.05). The role of mir-3196 mimics is similar to VPA. While, the miR-3196 inhibitor had the opposite effect to VPA and mimics. The combination of VPA and miR-3196 mimics has the most obvious effect. Conclusion: VPA can inhibit the proliferation of Hut 78 cells and promote cell apoptosis and the structure and dysfunction of mitochondria by regulating the activity of the PI3K/AKT pathway.

Bioinspired Iron-Catalyzed Dehydration of Aldoximes to Nitriles: A General N-O Redox-Cleavage Method.

Inspired by OxdA that operates biocatalytic aldoxime dehydration, we have developed an efficient iron catalyst, Cp*Fe(1,2-Cy2PC6H4O) (1), which rapidly converts various aliphatic and aromatic aldoximes to nitriles with release of H2O at room temperature. The catalysis involves redox activation of the N-O bond by a 1e- transfer from the iron catalyst to the oxime. Such redox-mediated N-O cleavage was demonstrated by the isolation of a ferrous iminato intermediate from the reaction of the ketoxime substrate. This iron-catalyzed acceptorless dehydration approach represents a general method for the preparation of nitriles, and it also delivers salicylonitriles by catalyzing the Kemp elimination reaction.

A Hybrid Imaging Platform(CT/PET/FMI) for Evaluating Tumor Necrosis and Apoptosis in Real-Time.

Multimodality imaging is an advanced imaging tool for monitoring tumor behavior and therapy in vivo. In this study, we have developed a novel hybrid tri-modality system that includes two molecular imaging methods: positron emission computed tomography (PET) and fluorescence molecular imaging (FMI) and the anatomic imaging modality X-ray computed tomography (CT). The following paper describes the system development. Also, its imaging performance was tested in vitro (phantom) and in vivo, in Balb/c nude mice bearing a head and neck tumor xenograft treated with novel gene therapy [a new approach to the delivery of recombinant bacterial gene (IL-24-expressing strain)]. Using the tri-modality imaging system, we simultaneously monitored the therapeutic effect, including the apoptotic and necrotic induction within the tumor in vivo. The apoptotic induction was examined in real-time using an 18F-ML-10 tracer; the cell death was detected using ICG. A CT was used to evaluate the anatomical situation. An increased tumor inhibition (including tumor growth and tumor cell apoptosis) was observed in the treatment group compared to the control groups, which further confirmed the therapeutic effect of a new IL-24-expressing strain gene therapy on the tumor in vivo. By being able to offer concurrent morphological and functional information, our system is able to characterize malignant tissues more accurately. Therefore, this new tri-modality system (PET/CT/FMI) is an effective imaging tool for simultaneously investigating and monitoring tumor progression and therapy outcomes in vivo.

The deubiquitinase OTUD1 inhibits colonic inflammation by suppressing RIPK1-mediated NF-κB signaling.

The E3 ubiquitin ligase (E3)-mediated ubiquitination and deubiquitinase (DUB)-mediated deubiquitination processes are closely associated with the occurrence and development of colonic inflammation. Ovarian tumor deubiquitinase 1 (OTUD1) is involved in immunoregulatory functions linked to infectious diseases. However, the effect of OTUD1 on intestinal immune responses during colonic inflammatory disorders such as inflammatory bowel disease (IBD) remains unclear. Here, we show that loss of OTUD1 in mice contributes to the pathogenesis of dextran sulfate sodium (DSS)-induced colitis via excessive release of proinflammatory cytokines. In addition, bone marrow transplantation experiments revealed that OTUD1 in hematopoietic cells plays a dominant role in protection against colitis. Mechanistically, OTUD1 physically interacts with receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and selectively cleaves K63-linked polyubiquitin chains from RIPK1 to inhibit the recruitment of NF-κB essential modulator (NEMO). Moreover, the expression of OTUD1 in mucosa samples from ulcerative colitis (UC) patients was lower than that in mucosa samples from healthy controls. Furthermore, we demonstrate that the UC-associated OTUD1 G430V mutation abolishes the ability of OTUD1 to inhibit RIPK1-mediated NF-κB activation and intestinal inflammation. Taken together, our study unveils a previously unexplored role of OTUD1 in moderating intestinal inflammation by inhibiting RIPK1-mediated NF-κB activation, suggesting that the OTUD1-RIPK1 axis could be a potential target for the treatment of IBD.

OTULIN allies with LUBAC to govern angiogenesis by editing ALK1 linear polyubiquitin.

OTULIN coordinates with LUBAC to edit linear polyubiquitin chains in embryonic development, autoimmunity, and inflammatory diseases. However, the mechanism by which angiogenesis, especially that of endothelial cells (ECs), is regulated by linear ubiquitination remains unclear. Here, we reveal that constitutive or EC-specific deletion of Otulin resulted in arteriovenous malformations and embryonic lethality. LUBAC conjugates linear ubiquitin chains onto Activin receptor-like kinase 1 (ALK1), which is responsible for angiogenesis defects, inhibiting ALK1 enzyme activity and Smad1/5 activation. Conversely, OTULIN deubiquitinates ALK1 to promote Smad1/5 activation. Consistently, embryonic survival of Otulin-deficient mice was prolonged by BMP9 pretreatment or EC-specific ALK1Q200D (constitutively active) knockin. Moreover, mutant ALK1 from type 2 hereditary hemorrhagic telangiectasia (HHT2) patients exhibited excessive linear ubiquitination and increased HOIP binding. As such, a HOIP inhibitor restricted the excessive angiogenesis of ECs derived from ALK1G309S-expressing HHT2 patients. These results show that OTULIN and LUBAC govern ALK1 activity to balance EC angiogenesis.

The Absence of PTEN in Breast Cancer Is a Driver of MLN4924 Resistance.

Background: Numerous studies have indicated that the neddylation pathway is closely associated with tumor development. MLN4924 (Pevonedistat), an inhibitor of the NEDD8-activating E1 enzyme, is considered a promising chemotherapeutic agent. Recently, we demonstrated that neddylation of the tumor suppressor PTEN occurs under high glucose conditions and promotes breast cancer development. It has been shown, however, that PTEN protein levels are reduced by 30-40% in breast cancer. Whether this PTEN deficiency affects the anti-tumor function of MLN4924 is unknown. Methods: In the present study, cell counting kit-8 and colony formation assays were used to detect cell proliferation, and a transwell system was used to quantify cell migration. A tumor growth assay was performed in BALB/c nude mice. The subcellular location of PTEN was detected by fluorescence microscopy. The CpG island of the UBA3 gene was predicted by the Database of CpG Islands and UCSC database. Western blotting and qRT-PCR were used to measure the expression of indicated proteins. The Human Protein Atlas database, the Cancer Genome Atlas and Gene Expression Omnibus datasets were used to validate the expression levels of UBA3 in breast cancer. Results: Our data show that the anti-tumor efficacy of MLN4924 in breast cancer cells was markedly reduced with the deletion of PTEN. PI3K/Akt signaling pathway activity correlated positively with UBA3 expression. Pathway activity correlated negatively with NEDP1 expression in PTEN-positive breast cancer patients, but not in PTEN-negative patients. We also demonstrate that high glucose conditions upregulate UBA3 mRNA by inhibiting UBA3 promoter methylation, and this upregulation results in the overactivation of PTEN neddylation in breast cancer cells. Conclusion: These data suggest a mechanism by which high glucose activates neddylation. PTEN is critical, if not indispensable, for MLN4924 suppression of tumor growth; PTEN status thus may help to identify MLN4924-responsive breast cancer patients.

Advances in Cancer Treatment by Targeting the Neddylation Pathway.

Developmental down-regulation protein 8 (NEDD8), expressed by neural progenitors, is a ubiquitin-like protein that conjugates to and regulates the biological function of its substrates. The main target of NEDD8 is cullin-RING E3 ligases. Upregulation of the neddylation pathway is closely associated with the progression of various tumors, and MLN4924, which inhibits NEDD8-activating enzyme (NAE), is a promising new antitumor compound for combination therapy. Here, we summarize the latest progress in anticancer strategies targeting the neddylation pathway and their combined applications, providing a theoretical reference for developing antitumor drugs and combination therapies.

Neddylation of PTEN regulates its nuclear import and promotes tumor development.

PTEN tumor suppressor opposes the PI3K/Akt signaling pathway in the cytoplasm and maintains chromosomal integrity in the nucleus. Nucleus-cytoplasm shuttling of PTEN is regulated by ubiquitylation, SUMOylation and phosphorylation, and nuclear PTEN has been proposed to exhibit tumor-suppressive functions. Here we show that PTEN is conjugated by Nedd8 under high glucose conditions, which induces PTEN nuclear import without effects on PTEN stability. PTEN neddylation is promoted by the XIAP ligase and removed by the NEDP1 deneddylase. We identify Lys197 and Lys402 as major neddylation sites on PTEN. Neddylated PTEN accumulates predominantly in the nucleus and promotes rather than suppresses cell proliferation and metabolism. The nuclear neddylated PTEN dephosphorylates the fatty acid synthase (FASN) protein, inhibits the TRIM21-mediated ubiquitylation and degradation of FASN, and then promotes de novo fatty acid synthesis. In human breast cancer tissues, neddylated PTEN correlates with tumor progression and poor prognosis. Therefore, we demonstrate a previously unidentified pool of nuclear PTEN in the Nedd8-conjugated form and an unexpected tumor-promoting role of neddylated PTEN.