MDH2 Stimulated by Estrogen-GPR30 Pathway Down-Regulated PTEN Expression Promoting the Proliferation and Invasion of Cells in Endometrial Cancer

Transcription Factor STAT3-Activated LDHB Promotes Tumor Properties of Endometrial Cancer Cells by Inducing MDH2 Expression

The pathogenesis of endometrial cancer (EC) involves the regulation of lactate dehydrogenases. However, the role and mechanism of lactate dehydrogenase-B (LDHB) in EC progression have not been studied. The mRNA levels of LDHB and malate dehydrogenase 2 (MDH2) were detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blotting and immunohistochemistry assays. Cell proliferation, apoptosis, and invasion were analyzed by 5-Ethynyl-2'-deoxyuridine, transwell, and flow cytometry assay, respectively. Glycolysis was investigated using Glucose Assay Kit, CheKine™ Micro Lactate Assay Kit, and ADP/ATP ratio assay kit. An in vivo tumor formation assay was conducted to disclose the effect of LDHB on tumor growth in vivo. The associations among signal transducer and activator of transcription 3 (STAT3), LDHB, and MDH2 were predicted through JASPAR or GeneMANIA online database and identified by chromatin immunoprecipitation assay, dual-luciferase reporter assay, and co-immunoprecipitation assay. LDHB expression was increased in EC tissues and cells in comparison with normal endometrial tissues and human endometrial stromal cells. LDHB had the potential as a biomarker to predict the prognosis of EC patients. In addition, LDHB knockdown inhibited the proliferation, invasion, and glycolysis and promoted apoptosis of RL95-2 and Ishikawa cells. LDHB knockdown inhibited tumor property of Ishikawa cells in vivo. STAT3 bound to the promoter region of LDHB, and STAT3 silencing-induced effects were relieved after LDHB upregulation. LDHB interacted with and regulated MDH2 expression. Moreover, MDH2 overexpression rescued LDHB knockdown-induced effects on EC cell phenotypes. STAT3-activated LDHB promoted endometrial cancer cell malignancy by inducing MDH2 production.

A Rare Variant in MDH2 (rs111879470) Is Associated with Predisposition to Recurrent Breast Cancer in an Extended High-Risk Pedigree

A significant fraction of breast cancer recurs, with lethal outcome, but specific genetic variants responsible have yet to be identified. Five cousin pairs with recurrent breast cancer from pedigrees with a statistical excess of recurrent breast cancer were sequenced to identify rare, shared candidate predisposition variants. The candidates were tested for association with breast cancer risk with UKBiobank data. Additional breast cancer cases were assayed for a subset of candidate variants to test for co-segregation. Three-dimensional protein structure prediction methods were used to investigate how the mutation under consideration is predicted to change structural and electrostatic properties in the mutated protein. One hundred and eighty-one rare candidate predisposition variants were shared in at least one cousin pair from a high-risk pedigree. A rare variant in MDH2 was found to segregate with breast-cancer-affected relatives in one extended pedigree. MDH2 is an estrogen-stimulated gene encoding the protein malate dehydrogenase, which catalyzes the reversible oxidation of malate to oxaloacetate. The molecular simulation results strongly suggest that the mutation changes the NAD+ binding pocket electrostatics of MDH2. This small sequencing study, using a powerful approach based on recurrent breast cancer cases from high-risk pedigrees, identified a set of strong candidate variants for inherited predisposition for breast cancer recurrence, including MDH2, which should be pursued in other resources.

Glucose metabolic reprogramming and its therapeutic potential in obesity-associated endometrial cancer

Endometrial cancer (EC) is a common gynecological cancer that endangers women health. Although substantial progresses of EC management have been achieved in recent years, the incidence of EC still remains high. Obesity has been a common phenomenon worldwide that increases the risk of EC. However, the mechanism associating obesity and EC has not been fully understood. Metabolic reprogramming as a remarkable characteristic of EC is currently emerging. As the primary factor of metabolic syndrome, obesity promotes insulin resistance, hyperinsulinemia and hyperglycaemia. This metabolic disorder remodels systemic status, which increases EC risk and is related with poor prognosis. Glucose metabolism in EC cells is complex and mediated by glycolysis and mitochondria to ensure energy requirement. Factors that affect glucose metabolism may have an impact on EC initiation and progression. In this study, we review the glucose metabolic reprogramming of EC not only systemic metabolism but also inherent tumor cell metabolism. In particular, the role of glucose metabolic regulation in malignant properties of EC will be focused. Understanding of metabolic profile and glucose metabolism-associated regulation mechanism in EC may provide novel perspective for treatment.

The construction and analysis of tricarboxylic acid cycle related prognostic model for cervical cancer

Introduction: Cervical cancer (CC) is the fourth most common malignant tumor in term of in incidence and mortality among women worldwide. The tricarboxylic acid (TCA) cycle is an important hub of energy metabolism, networking one-carbon metabolism, fatty acyl metabolism and glycolysis. It can be seen that the reprogramming of cell metabolism including TCA cycle plays an indispensable role in tumorigenesis and development. We aimed to identify genes related to the TCA cycle as prognostic markers in CC. Methods: Firstly, we performed the differential expressed analysis the gene expression profiles associated with TCA cycle obtained from The Cancer Genome Atlas (TCGA) database. Differential gene list was generated and cluster analysis was performed using genes with detected fold changes >1.5. Based on the subclusters of CC, we analysed the relationship between different clusters and clinical information. Next, Cox univariate and multivariate regression analysis were used to screen genes with prognostic characteristics, and risk scores were calculated according to the genes with prognostic characteristics. Additionally, we analyzed the correlation between the predictive signature and the treatment response of CC patients. Finally, we detected the expression of ench prognostic gene in clinical CC samples by quantitative polymerase chain reaction (RT-qPCR). Results: We constructed a prognostic model consist of seven TCA cycle associated gene (ACSL1, ALDOA, FOXK2, GPI, MDH1B, MDH2, and MTHFD1). Patients with CC were separated into two groups according to median risk score, and high-risk group had a worse prognosis compared to the low-risk group. High risk group had lower level of sensitivity to the conventional chemotherapy drugs including cisplatin, paclitaxel, sunitinib and docetaxel. The expression of ench prognostic signature in clinical CC samples was verified by qRT-PCR. Conclusion: There are several differentially expressed genes (DEGs) related to TCA cycle in CC. The risk score model based on these genes can effectively predict the prognosis of patients and provide tumor markers for predicting the prognosis of CC.

MDH1 and MDH2 Promote Cell Viability of Primary AT2 Cells by Increasing Glucose Uptake

Background

Acute lung injury (ALI) is a clinical disease with high morbidity and mortality, with limited treatment means. For primary alveolar epithelial type II (AT2) cells, glycolysis is an essential bioenergetic process. However, the significance of AT2 cell glycolysis in sepsis ALI remains unknown.

Methods and Results

In the current study, based on microarray analysis, real-time quantitative PCR, and Western blotting, we found that the hsa00020: citrate cycle pathway was inactivated, specifically its downstream gene: malate dehydrogenase 1 (MDH1) and MDH2 in ALI. In this context, lipopolysaccharides (LPS) were used to construct the septic-ALI mouse model and the biological function of MDH1 and MDH2 in primary alveolar epithelial type II (AT2) cells was explored. Through CCK-8, EdU, transwell, and apoptosis assays, we found that MDH1 and MDH2 promoted the cell vitality of AT2 cells, which relied on MDH1 and MDH2 to promote the glucose intake of AT2 cells.

Conclusion

Overall, these findings suggest that targeting MDH1/MDH2-mediated AT2 cell glycolysis may be a potential strategy for ALI patients.

Integrated genomic, transcriptomic and metabolomic analysis reveals MDH2 mutation-induced metabolic disorder in recurrent focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) has an over 30% risk of recurrence after kidney transplantation (Ktx) and is associated with an extremely high risk of graft loss. However, mechanisms remain largely unclear. Thus, this study identifies novel genes related to the recurrence of FSGS (rFSGS). Whole genome-wide sequencing and next-generation RNA sequencing were used to identify the candidate mutant genes associated with rFSGS in peripheral blood mononuclear cells (PBMCs) from patients with biopsy-confirmed rFSGS after KTx. To confirm the functional role of the identified gene with the MDH2 c.26C >T mutation, a homozygous MDH2 c.26C >T mutation in HMy2.CIR cell line was induced by CRISPR/Cas9 and co-cultured with podocytes, mesangial cells, or HK2 cells, respectively, to detect the potential pathogenicity of the c.26C >T variant in MDH2. A total of 32 nonsynonymous single nucleotide polymorphisms (SNPs) and 610 differentially expressed genes (DEGs) related to rFSGS were identified. DEGs are mainly enriched in the immune and metabolomic-related pathways. A variant in MDH2, c.26C >T, was found in all patients with rFSGS, which was also accompanied by lower levels of mRNA expression in PBMCs from relapsed patients compared with patients with remission after KTx. Functionally, co-cultures of HMy2.CIR cells overexpressing the mutant MDH2 significantly inhibited the expression of synaptopodin, podocin, and F-actin by podocytes compared with those co-cultured with WT HMy2.CIR cells or podocytes alone. We identified that MDH2 is a novel rFSGS susceptibility gene in patients with recurrence of FSGS after KTx. Mutation of the MDH2 c.26C >T variant may contribute to progressive podocyte injury in rFSGS patients.

The OmpA of commensal Escherichia coli of CRC patients affects apoptosis of the HCT116 colon cancer cell line

BACKGROUND

Colorectal cancer ranks third globally among all types of cancers. Dysbiosis of the gut microbiota of people with CRC is one of the effective agents in the tumorigenesis and metastasis in this type of cancer. The population of Escherichia coli strains, a component of gut microbiota, is increased in the gut of people with CRC compared with healthy people. So, E.coli strains isolated from these patients may have a role in tumorigenesis. Because the most isolated strains belong to the B2 phylogenuetic group, there seems to be a linkage between the bacterium components and malignancy.

MATERIAL AND METHODS

In this study, the proteomic comparison between isolated Ecoli from CRC patients and healthy people was assayed. The isolated spot was studied by Two-dimensional gel electrophoresis (2DE) and Liquid chromatography-mass spectrometry (LC-MS). The results showed that the expression of Outer membrane protein A (OmpA) protein increased in the commensal E.coli B2 phylogenetic group isolated from CRC patients. Additionally, we analyzed the effect of the OmpA protein on the expression of the four genes related to apoptosis in the HCT116 colon cancer cell line.

RESULTS

This study identified that OmpA protein was overexpressed in the commensal E.coli B2 phylogenetic group isolated from CRC patients compared to the E.coli from the control group. This protein significantly decreased the expression of Bax and Bak, pro-apoptotic genes, as well as the expression of P53 in the HCT116 Cell Line, P < 0.0001. LC-MS and protein bioinformatics results confirmed that this protein is outer membrane protein A, which can bind to nucleic acid and some of the organelle proteins on the eukaryotic cell surface.

CONCLUSIONS

According to our invitro and insilico investigations, OmpA of gut E.coli strains that belong to the B2 phylogenetic group can affect the eukaryotic cell cycle.

Identification of proteins associated with treatment response of neoadjuvant chemoradiotherapy in rectal mucinous adenocarcinoma by co-expression network analysis based on proteomic analysis

For rectal mucinous adenocarcinoma (MAC), identifying biomarkers of neoadjuvant chemoradiotherapy (NCRT) response has become imperative. This study applied label-free mass spectrometry and weighted gene co-expression network analysis to identify hub proteins in association with the NCRT response in 20 rectal MAC patients. We identified 131 differentially abundant proteins and 7 candidate proteins associated with the NCRT response. The immunostaining expressions of six proteins (ENOA, ILEU, MDHM, RM11, PTGDS, and RL3) were significantly associated with the NCRT response. Logistic regression analysis revealed that ENOA (OR = 6.275, P = 0.006) was independent risk hub protein for the NCRT response. Tow hub proteins (ENOA and PTGDS) were identified as significant risk factors by Cox regression analysis. A prognostic risk score system was constructed: risk score = (0.910 × EXP_ENOA) + (-1.519 × EXP_PTGDS), and found to be an independent predictor of DFS in rectal MAC patients (HR = 10.308, P < 0.001). Our study suggested that ENOA may be a novel biomarker for the NCRT response and prognosis in rectal MAC patients. A two-hub-protein-based risk score system might be used for predicting tumor recurrence in rectal MAC patients. SIGNIFICANCE: NCRT resistance is a major problem in the treatment of rectal MAC patients. Identifying robust predictive biomarkers for NCRT resistance is beneficial to the stratified treatment of rectal MAC patients. In this study, label-free mass spectrometry and weighted gene co-expression network analysis identified ENOA as a potential novel biomarker for the NCRT response and prognosis. ENOA may be involved in the process of the NCRT resistance and tumor recurrence through the carbon metabolism pathway.

Construction and validation of a novel prognostic signature for uveal melanoma based on five metabolism-related genes

BACKGROUND

Uveal melanoma (UM) is the most aggressive intraocular tumor worldwide. Accurate prognostic models are urgently needed. The present research aimed to construct and validate a prognostic signature is associated with overall survival (OS) for UM patients based on metabolism-related genes (MRGs).

METHODS

MRGs were obtained from molecular signature database (MSigDB). The gene expression profiles and patient clinical data were downloaded from The Cancer Genome Atlas (TCGA) database. In the training datasets, MRGs were analyzed through univariate Cox regression analyses and least absolute shrinkage and selection operator (LASSO) Cox analyses to build a prognostic model. The GSE84976 was treated as the validation cohort. In addition, time-dependent receiver operating characteristic (ROC) and Kaplan-Meier survival curve analyses the reliability of the developed model. Then, gene set enrichment analysis (GSEA) was used for gene enrichment analysis. Nomogram that combined the five-gene signature was used to evaluate the predictive OS value of UM patients.

RESULTS

Five MRGs were identified and used to establish the prognostic model for UM patients. The model was successfully validated using the testing cohort. Moreover, ROC analysis demonstrated a strong predictive ability that our prognostic signature had for UM prognosis. Multivariable Cox regression analysis revealed that the risk model was an independent predictor of prognosis. UM patients with a high-risk score showed a higher level of immune checkpoint molecules.

CONCLUSION

We established a novel metabolism-related signature that could predict survival and might be therapeutic targets for the treatment of UM patients.

LncRNA AC020978 facilitates non-small cell lung cancer progression by interacting with malate dehydrogenase 2 and activating the AKT pathway

Long non–coding RNA AC020978 (lncRNA AC020978) is an oncogenic regulator of non–small cell lung cancer (NSCLC). However, the function of AC020978 in regulating NSCLC metastasis and the potential molecular mechanism remains largely unknown. In this study, we evaluated the expression levels of AC020978 in a series of NSCLC tissues using FISH assays and found that higher AC020978 expression levels were closely associated with metastasis and unfavorable prognosis. Functional studies showed that AC020978 promoted NSCLC migration and invasion both in vitro and in vivo. Further investigation demonstrated that AC020978 interacted with malate dehydrogenase 2 (MDH2) and maintained MDH2 stability. Knockdown of MDH2 weakened the facilitating effect on cell metastasis and 2‐hydroxyglutarate (2‐HG) metabolism in AC020978‐overexpressed NSCLC cells. RNA sequencing, bioinformatic analysis, and western blotting revealed that AC020978 was associated with the AKT signaling pathway. Taken together, our findings revealed that AC020978 might serve as a prognostic biomarker and activate the AKT pathway by stabilizing MDH2, leading to metastasis and progression of NSCLC.

Urinary malate dehydrogenase 2 is a new biomarker for early detection of non-small-cell lung cancer

Reliable and noninvasive biomarkers for the early diagnosis of non‐small‐cell lung cancer (NSCLC) are an unmet need. This study aimed to screen and validate potential urinary biomarkers for the early diagnosis of NSCLC. Using protein mass spectrometry, urinary MDH2 was found to be abundant both in patients with lung cancer and lung cancer model mice compared with controls. Urine samples obtained as retrospective and prospective cohorts including 1091 NSCLC patients and 736 healthy controls were measured using ELISA. Patients with stage I NSCLC had higher urinary MDH2 compared with healthy controls. The area under the receiver‐operating characteristic curve (AUC) for the urinary MDH2 was 0.7679 and 0.7234 in retrospective and prospective cohorts to distinguish stage I cases from controls. Urinary MDH2 levels correlated with gender and smoking history. MDH2 expression levels were elevated in lung cancer tissues. MDH2 knockdown using shRNA inhibited the proliferation of lung cancer cells. Our study demonstrated that urinary MDH2 concentration was higher in early‐stage NSCLC patients compared with that in controls and that MDH2 could serve as a potential biomarker for early detection of NSCLC.

[Abnormal gut microbiota-induced hypoestrogenemia as a possible risk factor for malignancy in endometrioid heterotopia]

This paper reveals the pathogenetic impact of the abnormal gut microbiota on the development of female reproductive system diseases. A dynamic imbalance between the altered microbiota and the macroorganism has many manifestations as hormonal homeostatic disorders, one of which is dysbiosis-induced hypoestrogenemia. Using endometrioid heterotopia as an example, the authors trace the possibility of its progression and malignancy due to the occurrence of primary breakdown of the PTEN tumor-suppressor gene with subsequent genetic abnormalities in the ARID1A and TP53 genes. PTEN mutation in both endometriosis itself and its malignancy indicates that dysbiosis-induced hypoestrogenemia may be implicated in the pathogenesis of endometriosis. Thus, the relationship between female reproductive system diseases and gut microbiome disorders may be more significant; and the possibility of correcting the gut microbiota with prebiotics and probiotics opens new horizons not only in the prevention, but also in the treatment of many gynecological diseases associated with hormone disorders.

Estrogen Enhances Endometrial Cancer Cells Proliferation by Upregulation of Prohibitin

Estrogen plays an essential role in type I endometrial cancer cell proliferation. Despite great progresses in the etiology has been obtained in the past, however, the molecular mechanisms remain to be fully clarified. Prohibitin has been demonstrated involvement in multiple cancers' development. If it also contributes to estrogen-driven endometrial cancer proliferation is not clear. IHC assay result display that prohibitin overexpressed in endometrial cancer tissue and associated with the poor prognosis; Western blot assay detect that upregulated prohibitin expression with dose- and time-dependent manners. The cellular growth was monitored with SRB assay which demonstrate that knockdown prohibitin attenuated estrogen-induced proliferation. Ubiquitination assay finds estrogen increased prohibitin level through stabilizing prohibitin protein via inhibition of ubiquitination, while estrogen-induced protein expression was mediated by estrogen receptor. Our findings provide a new insight on the mechanism of estrogen-induced proliferation, implying the possibility of using prohibitin as a potential therapeutic target for the treatment of endometrial cancer.