Setd2 deficiency promotes gastric tumorigenesis through inhibiting the SIRT1/FOXO pathway.

Gastric cancer (GC) is the fifth most common cancer and the second leading cause of cancer death globally. SETD2 is a histone methyltransferase catalyzing tri-methylation of H3K36 (H3K36me3) and has been shown to participate in diverse biological processes and human tumors. However, the mechanism of SETD2 in GC remains unclear. Here, we reported that Setd2 deficiency predicts poor prognosis of gastric cancer. SETD2 loss facilitated H. felis/MNU and c-Myc-induced gastric tumorigenesis, respectively. The mouse model of stomach-specific Setd2 depletion together with c-MYC overexpression (AMS) developed high-grade epithelial defects, intestinal metaplasia and dysplasia at only 10-12 weeks of age. Mechanistically, Setd2 depletion resulted in impaired epigenetic regulation of Sirt1, thus inhibiting the SIRT1/FOXO pathway. Moreover, the agonists of FOXO signaling or overexpression of SIRT1 significantly rescued the enhanced cell proliferation and migration caused by Setd2 deficiency in SGC7901 cells. Together, our findings highlight an epigenetic mechanism by which SETD2 regulates gastric tumorigenesis through SIRT1/FOXO pathway. It may also pave the way for the development of targeted, patient-tailored therapies for GC patients with Setd2 deficiency.

Loss of SETD2 aggravates colorectal cancer progression caused by SMAD4 deletion through the RAS/ERK signalling pathway.

BACKGOUND: Colorectal cancer (CRC) is a complex, multistep disease that arises from the interplay genetic mutations and epigenetic alterations. The histone H3K36 trimethyltransferase SET domain-containing 2 (SETD2), as an epigenetic signalling molecule, has a 5% mutation rate in CRC. SETD2 expression is decreased in the development of human CRC and mice treated with Azoxymethane /Dextran sodium sulfate (AOM/DSS). Loss of SETD2 promoted CRC development. SMAD Family member 4 (SMAD4) has a 14% mutation rate in CRC, and SMAD4 ablation leads to CRC. The co-mutation of SETD2 and SMAD4 predicted advanced CRC. However, little is known on the potential synergistic effect of SETD2 and SMAD4. METHODS: CRC tissues from mice and SW620 cells were used as research subjects. Clinical databases of CRC patients were analyzed to investigate the association between SETD2 and SMAD4. SETD2 and SMAD4 double-knockout mice were established to further investigate the role of SETD2 in SMAD4-deficient CRC. The intestinal epithelial cells (IECs) were isolated for RNA sequencing and chromatin immunoprecipitation sequencing (ChIP-seq) to explore the mechanism and the key molecules resulting in CRC. Molecular and cellular experiments were conducted to analyze the role of SETD2 in SMAD4-deficient CRC. Finally, rescue experiments were performed to confirm the molecular mechanism of SETD2 in the development of SMAD4-dificient CRC. RESULTS: The deletion of SETD2 promotes the malignant progression of SMAD4-deficient CRC. Smad4Vil-KO ; Setd2Vil-KO mice developed a more severe CRC phenotype after AOM/DSS induction, with a larger tumour size and a more vigorous epithelial proliferation rate. Further mechanistic findings revealed that the loss of SETD2 resulted in the down-regulation of DUSP7, which is involved in the inhibition of the RAS/ERK signalling pathway. Finally, the ERK1/2 inhibitor SCH772984 significantly attenuated the progression of CRC in Smad4Vil-KO ;Setd2Vil-KO mice, and overexpression of DUSP7 significantly inhibited the proliferation rates of SETD2KO ; SMAD4KO SW620 cells. CONCLUSIONS: Our results demonstrated that SETD2 inhibits the RAS/ERK signaling pathway by facilitating the transcription of DUSP7 in SMAD4-deficient CRC, which could provide a potential therapeutic target for the treatment of advanced CRC.

SETD2 deficiency accelerates sphingomyelin accumulation and promotes the development of renal cancer.

Patients with polycystic kidney disease (PKD) encounter a high risk of clear cell renal cell carcinoma (ccRCC), a malignant tumor with dysregulated lipid metabolism. SET domain-containing 2 (SETD2) has been identified as an important tumor suppressor and an immunosuppressor in ccRCC. However, the role of SETD2 in ccRCC generation in PKD remains largely unexplored. Herein, we perform metabolomics, lipidomics, transcriptomics and proteomics within SETD2 loss induced PKD-ccRCC transition mouse model. Our analyses show that SETD2 loss causes extensive metabolic reprogramming events that eventually results in enhanced sphingomyelin biosynthesis and tumorigenesis. Clinical ccRCC patient specimens further confirm the abnormal metabolic reprogramming and sphingomyelin accumulation. Tumor symptom caused by Setd2 knockout is relieved by myriocin, a selective inhibitor of serine-palmitoyl-transferase and sphingomyelin biosynthesis. Our results reveal that SETD2 deficiency promotes large-scale metabolic reprogramming and sphingomyelin biosynthesis during PKD-ccRCC transition. This study introduces high-quality multi-omics resources and uncovers a regulatory mechanism of SETD2 on lipid metabolism during tumorigenesis.

SETD2 deficiency promotes renal fibrosis through the TGF-ß/Smad signalling pathway in the absence of VHL.

BACKGROUND: Renal fibrosis is the final development pathway and the most common pathological manifestation of chronic kidney disease. Epigenetic alteration is a significant intrinsic factor contributing to the development of renal fibrosis. SET domain-containing 2 (SETD2) is the sole histone H3K36 trimethyltransferase, catalysing H3K36 trimethylation. There is evidence that SETD2-mediated epigenetic alterations are implicated in many diseases. However, it is unclear what role SETD2 plays in the development of renal fibrosis. METHODS: Kidney tissues from mice as well as HK2 cells were used as research subjects. Clinical databases of patients with renal fibrosis were analysed to investigate whether SETD2 expression is reduced in the occurrence of renal fibrosis. SETD2 and Von Hippel-Lindau (VHL) double-knockout mice were used to further investigate the role of SETD2 in renal fibrosis. Renal tubular epithelial cells isolated from mice were used for RNA sequencing and chromatin immunoprecipitation sequencing to search for molecular signalling pathways and key molecules leading to renal fibrosis in mice. Molecular and cell biology experiments were conducted to analyse and validate the role of SETD2 in the development of renal fibrosis. Finally, rescue experiments were performed to determine the molecular mechanism of SETD2 deficiency in the development of renal fibrosis. RESULTS: SETD2 deficiency leads to severe renal fibrosis in VHL-deficient mice. Mechanically, SETD2 maintains the transcriptional level of Smad7, a negative feedback factor of the transforming growth factor-ß (TGF-ß)/Smad signalling pathway, thereby preventing the activation of the TGF-ß/Smad signalling pathway. Deletion of SETD2 leads to reduced Smad7 expression, which results in activation of the TGF-ß/Smad signalling pathway and ultimately renal fibrosis in the absence of VHL. CONCLUSIONS: Our findings reveal the role of SETD2-mediated H3K36me3 of Smad7 in regulating the TGF-ß/Smad signalling pathway in renal fibrogenesis and provide an innovative insight into SETD2 as a potential therapeutic target for the treatment of renal fibrosis.

Brochoscopic Airway Clearance Therapy vs. Conventional Sputum Aspiration: The Future of Flexible Brochoscopes in Intensive Care Units?

(1) Background: The aim of our study is to investigate the effectiveness of bronchoscopic airway clearance therapy (B-ACT) on severe pneumonia (SP) patients with invasive mechanical ventilation (IMV) in the intensive care unit (ICU). (2) Methods: Our study retrospectively enrolled 49 patients with sputum aspiration and 99 patients with B-ACT, and the latter were divided into the ≤once every 3 days group (n = 50) and >once every 3 days group (n = 49). (3) Results: We found most laboratory blood results were significantly improved in the B-ACT group as compared with those in sputum aspiration group (p < 0.05). Patients in the B-ACT group and those in ≤once every 3 days group also had significantly better survival to hospital discharge than those in their counterpart groups (Logrank p < 0.001). In patients with cardiopulmonary diseases or positive cultures for bacteria, the B-ACT group and those in the ≤once every 3 days group had significantly better survival outcomes to discharge than those in their counterpart groups (Logrank p < 0.001). B-ACT and the average frequency of ≤once every 3 days had significantly better impact on survival outcomes than their counterpart groups (HR: 0.444, 95% CI: 0.238-0.829, p = 0.011; HR: 0.285, 95% CI: 0163-0.498, p < 0.001). (4) Conclusions: In the future, flexible bronchoscopes may paly an important role in ACT for SP patients with IMV.

The Valuable Prognostic Impact of Regional Lymph Node Removed on Outcomes for IIIA N0 NSCLC Patients.

Background: Regional lymph nodes (RLNs) removed combined with surgery is a standard option for patients at stage I to IIIA NSCLC. The objective of the study is to clarify the effect of removing different number of RLNs on survival outcomes for patients at stage IIIA N0 NSCLC. Methods: Patients at stage IIIA N0 NSCLC from 2004 to 2015 were identified from Surveillance, Epidemiology, and End Results (SEER) database. Prior propensity score method (PSM), survival time was compared among different number (0, 1-3 and ≥4) of RLNs removed groups. After PSM, lung cancer-specific survival (LCSS) and overall survival (OS) were compared. Kaplan-Meier analysis and Cox regression analyses were used to clarify the impact of the factors on the prognosis with hazard ratio (HR) and 95% confidence interval (CI). Results: A total of 11,583 patients at stage IIIA N0 NSCLC were included. Prior PSM, survival indicators including 1-year mortality rate, 5-year mortality rate, median survival time (MDST) and mean survival time (MST) from good to bad were all: ≥4, 1-3 and none RLNs removed group. After PSM, Kaplan-Meier survival analyses and univariate Cox regression analyses on OS and LCSS revealed a statistically significance on survival curve (P<0.001) between each two of the three groups (none, 1-3 and ≥4 RLNs removed group). Multivariable Cox regression analyses on OS and LCSS showed an independent association of RLNs removed with higher OS (HR, 0.275; 95% CI, 0.259-0.291; P<0.001) and LCSS (HR, 0.239; 95% CI, 0.224-0.256; P<0.001) compared with none RLN removed and no statistical difference with OS (HR, 1.118; 95% CI, 0.983-1.271; P=0.088) and LCSS (HR, 1.107; 95% CI, 0.954-1.284; P=0.179) between 1-3 RLNs removed and ≥4 RLNs removed. Conclusions: Removing RLNs was beneficial to survival outcomes of patients at stage IIIA N0 NSCLC. Compared with 1-3 RLNs removed, ≥4 RLNs removed could bring a better survival time but not an independent prognostic factor (P>0.05).

The Clinical Characteristics and Treatments for Large Cell Carcinoma Patients Older than 65 Years Old: A Population-Based Study.

Background: Pulmonary large cell carcinoma, a type of non-small cell lung cancer (NSCLC), is a rare neoplasm with poor prognosis. In this study, our aim was to investigate the impact of radiation sequences with surgery for stage III/IV LCC patients between different age groups, especially in the elderly patients. Patients and Methods: The patients with LCC and other types of NSCLC in the Surveillance, Epidemiology and End Results (SEER) database from 2004 to 2015 were retrospectively analyzed. Then we divided the LCC patients into two age groups: <65 years old group and ≥65 years old group. Propensity score method (PSM) was used to control potential differences between different groups. The overall survival (OS) of LCC patients and other types of NSCLC patients were evaluated by Kaplan−Meier analysis. Univariate and multivariate Cox regression analysis were employed to explore the independent risk factors of OS. The forest plots of HRs for OS were generated to show the above outcomes more visually. Results: In total, 11,349 LCC patients and 129,118 other types of NSCLC patients were enrolled in this study. We divided LCC patients into <65 years old group (4300) and ≥65 years old group (7049). LCC patients was more common in whites (81.4%), males (58.3%), elderly (≥65 years old: 62.1%), east regions (52.7%), upper lobe (51.6%), right-origin of primary (55.4%), with advanced grade (54.2%) or stage (76.7%). After PSM, Kaplan−Meier analysis and multivariate Cox analysis showed significantly worse survival prognosis for LCC patients compared to other types of NSCLC, especially in the group ≥65 years old (HR: 1.230; 95% CI: 1.171−1.291; p < 0.001). For LCC patients, there were some risk survival factors including whites, males, not upper lobe, advanced stage, elder age at diagnosis, bone metastasis, liver metastasis, singled status, no lymphadenectomy, no surgery, and no chemotherapy (p < 0.05). In LCC patients ≥65 years old, radiation after surgery had significantly better impact on overall survival outcomes (HR: 0.863, 95% CI: 0.765−0.973, p = 0.016), whereas radiation prior to surgery (HR: 1.425, 95% CI: 1.059−1.916, p = 0.019) had significantly worse impact on prognosis of patients. In LCC patients <65 years old, radiation sequences with surgery had no significant impact on the OS of patients (p = 0.580), but ≥4 LNRs had significantly survival benefits to prognosis (HR:0.707, 95% CI: 0.584−0.855). Elderly LCC patients had worse malignant tumors than young patients, of which the majority were diagnosed as stage III/IV tumors. Conclusions: Postoperative radiotherapy may achieve a better prognosis for stage III/IV LCC patients older than 65 years old compared to other radiation sequences with surgery.

Exploration of the optimal number of regional lymph nodes removed for resected N0 NSCLC patients: A population-based study.

Background: The aim of our study was to explore the optimal number of regional lymph nodes removed (LNRs) in resected N0 non-small cell lung cancer (NSCLC) patients and identify potential risk factors. Methods: Included in this study were 55,024 N0 NSCLC patients between 2004 and 2015 based on the Surveillance, Epidemiology, and End Results database (SEER). All the patients were divided into No LNR group (57.8%), 1-3 LNRs group (8.1%) and ≥4 LNRs group (31.4%). Relevant clinical and patient parameters including overall survival (OS), lung cancer-specific survival (LCSS), gender, race, year of diagnosis, primary site, T stage, AJCC stage, laterality, histological type, lymphadenectomy, radiation, chemotherapy, age at diagnosis, insurance status, marital status, family income. Results: Kaplan-Meier analysis demonstrated LNRs had significantly better OS and LCSS than No LNRs in all the N0 NSCLC patients with different T stages (Logrank p<.001). Univariate and multivariate analysis showed that both OS and LCSS in ≥ 4 LNRs group were better than those in <1-3 LNRs group (OS: ≥4 LNRs group: HR, 0.583; 95%CI, 0.556-0.610; P<.001 vs.1-3 LNRs group: HR, 0.726; 95%CI, 0.687-0.769; P<.001; LCSS: ≥4 LNRs group: HR, 0.514; 95%CI, 0.480-0.550; P<.001 vs.1-3 LNRs group: HR, 0.647; 95%CI, 0.597-0.702; P<.001). In addition, whites, males, not upper lobe, large cell carcinoma and others, advance T stage or AJCC stage, no surgery, no LNR, no radiation, no chemotherapy, elder age at diagnosis, singled marital status and low family income had negative impact on prognosis of N0 NSCLC patients. Conclusions: Our study suggests that ≥ 4 LNRs can yield better survival outcomes compared with 1-3 LNRs in N0 NSCLC patients.

Advanced age is not the decisive factor in chemotherapy of small cell lung cancer: a population-based study.

OBJECTIVE: There is limited research on the impact of chemotherapy on the prognosis of different age group patients with small cell lung cancer (SCLC). The aim of this study was to explore the impact of chemotherapy on survival prognosis of elderly patients with SCLC. METHODS: Based on the Surveillance, Epidemiology and End Results (SEER) database, 57,460 SCLC patients between 2004 and 2015 were identified and divided into a ≤ 80 years group (n = 50,941) and a >80 years group (n = 6,519). Confounding factors were controlled by propensity score matching (PSM) analysis. Kaplan Meier (KM) analysis was performed to determine the impact of chemotherapy on overall survival (OS) and lung-cancer specific survival (LCSS) of the patients. Other variables that could affect survival of SCLC patients were also examined by COX analysis. RESULTS: KM analysis showed that both OS and LCSS were improved in chemotherapy group compared to those in non-chemotherapy group (log rank P < 0.001) in both age groups after PSM. Cox analysis demonstrated the survival benefit of chemotherapy in both ≤ 80 years group (OS: HR 0.435; 95% CI 0.424-0.447; LCSS: HR 0.436; 95% CI 0.424-0.448) and >80 years group (OS: HR 0.424; 95% CI 0.397-0.451; LCSS: HR 0.415; 95% CI 0.389-0.444). Additionally, the following parameters had a negative impact on survival of elderly patients: male sex, tumor location in main bronchus, increased stage, bilateral tumor, no surgery or radiation, and lower median household income. CONCLUSIONS: Elderly patients with SCLC should be encouraged to receive chemotherapy provided their general conditions permit.

SETD2 epidermal deficiency promotes cutaneous wound healing via activation of AKT/mTOR Signalling.

OBJECTIVES: Cutaneous wound healing is one of the major medical problems worldwide. Epigenetic modifiers have been identified as important players in skin development, homeostasis and wound repair. SET domain-containing 2 (SETD2) is the only known histone H3K36 tri-methylase; however, its role in skin wound healing remains unclear. MATERIALS AND METHODS: To elucidate the biological role of SETD2 in wound healing, conditional gene targeting was used to generate epidermis-specific Setd2-deficient mice. Wound-healing experiments were performed on the backs of mice, and injured skin tissues were collected and analysed by haematoxylin and eosin (H&E) and immunohistochemical staining. In vitro, CCK8 and scratch wound-healing assays were performed on Setd2-knockdown and Setd2-overexpression human immortalized keratinocyte cell line (HaCaT). In addition, RNA-seq and H3K36me3 ChIP-seq analyses were performed to identify the dysregulated genes modulated by SETD2. Finally, the results were validated in functional rescue experiments using AKT and mTOR inhibitors (MK2206 and rapamycin). RESULTS: Epidermis-specific Setd2-deficient mice were successfully established, and SETD2 deficiency resulted in accelerated re-epithelialization during cutaneous wound healing by promoting keratinocyte proliferation and migration. Furthermore, the loss of SETD2 enhanced the scratch closure and proliferation of keratinocytes in vitro. Mechanistically, the deletion of Setd2 resulted in the activation of AKT/mTOR signalling pathway, while the pharmacological inhibition of AKT and mTOR with MK2206 and rapamycin, respectively, delayed wound closure. CONCLUSIONS: Our results showed that SETD2 loss promoted cutaneous wound healing via the activation of AKT/mTOR signalling.

The histone methyltransferase SETD2 modulates oxidative stress to attenuate experimental colitis.

Epigenetic regulation disorder is important in the onset and pathogenesis of inflammatory bowel disease (IBD). SETD2, a trimethyltransferase of histone H3K36, is frequently mutated in IBD samples with a high risk of developing colorectal cancer (CRC). However, functions of SETD2 in IBD and colitis-associated CRC remain largely undefined. Here, we found that SETD2 modulates oxidative stress to attenuate colonic inflammation and tumorigenesis in mice. SETD2 expression became decreased in IBD patients and dextran sodium sulfate (DSS)-induced colitic mice. Setd2Vil-KO mice showed increased susceptibility to DSS-induced colitis, accompanied by more severe epithelial barrier disruption and markedly increased intestinal permeability that subsequently facilitated inflammation-associated CRC. Mechanistically, we found that Setd2 depletion resulted in excess reactive oxygen species (ROS) by directly down-regulating antioxidant genes, which led to defects in barrier integrity and subsequently inflammatory damage. Moreover, overexpression of antioxidant PRDX6 in Setd2Vil-KO intestinal epithelial cells (IECs) largely alleviated the overproductions of ROS and improved the cellular survival. Together, our findings highlight an epigenetic mechanism by which SETD2 modulates oxidative stress to regulate intestinal epithelial homeostasis and attenuate colonic inflammation and tumorigenesis. SETD2 might therefore be a pivotal regulator that maintains the homeostasis of the intestinal mucosal barrier.

Multilevel Regulation of ß-Catenin Activity by SETD2 Suppresses the Transition from Polycystic Kidney Disease to Clear Cell Renal Cell Carcinoma.

Patients with polycystic kidney disease (PKD) are at a high risk of developing renal cell carcinoma (RCC). However, little is known about genetic alterations or changes in signaling pathways during the transition from PKD to RCC. SET domain-containing 2 (SETD2) is a histone methyltransferase, which catalyzes tri-methylation of H3K36 (H3K36me3) and has been identified as a tumor suppressor in clear cell renal cell carcinoma (ccRCC), but the underlying mechanism remains largely unexplored. Here we report that knockout of SETD2 in a c-MYC-driven PKD mouse model drove the transition to ccRCC. SETD2 inhibited ß-catenin activity at transcriptional and posttranscriptional levels by competing with ß-catenin for binding promoters of target genes and maintaining transcript levels of members of the ß-catenin destruction complex. Thus, SETD2 deficiency enhanced the epithelial-to-mesenchymal transition and tumorigenesis through the hyperactivation of Wnt/ß-catenin signaling. Our findings reveal previously unrecognized roles of SETD2-mediated competitive DNA binding and H3K36me3 modification in regulating Wnt/ß-catenin signaling during the transition from PKD to ccRCC. The novel autochthonous mouse models of PKD and ccRCC will be useful for preclinical research into disease progression. SIGNIFICANCE: These findings characterize multiple mechanisms by which SETD2 inhibits ß-catenin activity during the transition of polycystic kidney disease to renal cell carcinoma, providing a potential therapeutic strategy for high-risk patients. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/13/3554/F1.large.jpg.

Stomach-specific c-Myc overexpression drives gastric adenoma in mice through AKT/mammalian target of rapamycin signaling.

Gastric cancer (GC) is one of the most common malignant cancers in the world. c-Myc, a well-known oncogene, is commonly amplified in many cancers, including gastric cancer. However, it is still not completely understood how c-Myc functions in GC. Here, we generated a stomach-specific c-Myc transgenic mouse model to investigate its role in GC. We found that overexpression of c-Myc in Atp4b+ gastric parietal cells could induce gastric adenoma in mice. Mechanistically, c-Myc promoted tumorigenesis via the AKT/mTOR pathway. Furthermore, AKT inhibitor (MK-2206) or mTOR inhibitor (Rapamycin) inhibited the proliferation of c-Myc overexpressing gastric cancer cell lines. Thus, our findings highlight that gastric tumorigenesis can be induced by c-Myc overexpression through activation of the AKT/mTOR pathway.

Di-Ras2 promotes renal cell carcinoma formation by activating the mitogen-activated protein kinase pathway in the absence of von Hippel-Lindau protein.

Clear cell renal cell carcinoma (ccRCC) is one of the most common and lethal human urological malignancies in the world. One of the pathological drivers for ccRCC is the Ras family of small GTPases that function as "molecular switches" in many diseases including ccRCC. Among the GTPases in the Di-Ras family, DIRAS2 gene encodes a GTPase that shares 60% homology to Ras and Rap. Yet little is known about the biological function(s) of Di-Ras2 or how its activities are regulated. In this study, we focused on Di-Ras2, and determined its functions and underlying mechanism during formation of ccRCC. We found that Di-Ras2 was upregulated in ccRCC, and promoted the proliferation, migration and invasion of human ccRCC cells in the absence of von Hippel-Lindau protein (pVHL). Mechanistically, Di-Ras2 induces and regulates ccRCC formation by modulating phosphorylation of the downstream effectors and activating the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. Moreover, Di-Ras2 interacts with E3 ubiquitin ligase, pVHL, which facilitates the ubiquitination and degradation of Di-Ras2. Together, these results indicate a potential function of Di-Ras2 as an oncogene in ccRCC, and these data provide a new perspective of the relationship between pVHL and the MAPK pathway in ccRCC tumorigenesis.