LRPPRC promotes glycolysis by stabilising LDHA mRNA and its knockdown plus glutamine inhibitor induces synthetic lethality via m6 A modification in triple-negative breast cancer.

BACKGROUND: Targeted therapy for triple-negative breast cancer (TNBC) remains a challenge. N6-methyladenosine (m6 A) is the most abundant internal mRNA modification in eukaryotes, and it regulates the homeostasis and function of modified RNA transcripts in cancer. However, the role of leucine-rich pentatricopeptide repeat containing protein (LRPPRC) as an m6 A reader in TNBC remains poorly understood. METHODS: Western blotting, reverse transcription-polymerase chain reaction (RT-qPCR) and immunohistochemistry were used to investigate LRPPRC expression levels. Dot blotting and colorimetric enzyme linked immunosorbent assay (ELISA) were employed to detect m6 A levels. In vitro functional assays and in vivo xenograft mouse model were utilised to examine the role of LRPPRC in TNBC progression. Liquid chromatography-mass spectrometry/mass spectrometry and Seahorse assays were conducted to verify the effect of LRPPRC on glycolysis. MeRIP-sequencing, RNA-sequencing, MeRIP assays, RNA immunoprecipitation assays, RNA pull-down assays and RNA stability assays were used to identify the target genes of LRPPRC. Patient-derived xenografts and organoids were employed to substantiate the synthetic lethality induced by LRPPRC knockdown plus glutaminase inhibition. RESULTS: The expressions of LRPPRC and m6 A RNA were elevated in TNBC, and the m6 A modification site could be recognised by LRPPRC. LRPPRC promoted the proliferation, metastasis and glycolysis of TNBC cells both in vivo and in vitro. We identified lactate dehydrogenase A (LDHA) as a novel direct target of LRPPRC, which recognised the m6 A site of LDHA mRNA and enhanced the stability of LDHA mRNA to promote glycolysis. Furthermore, while LRPPRC knockdown reduced glycolysis, glutaminolysis was enhanced. Moreover, the effect of LRPPRC on WD40 repeat domain-containing protein 76 (WDR76) mRNA stability was impaired in an m6 A-dependent manner. Then, LRPPRC knockdown plus a glutaminase inhibition led to synthetic lethality. CONCLUSIONS: Our study demonstrated that LRPPRC promoted TNBC progression by regulating metabolic reprogramming via m6 A modification. These characteristics shed light on the novel combination targeted therapy strategies to combat TNBC.

FLOT1 promotes gastric cancer progression and metastasis through BCAR1/ERK signaling.

Flotillin-1 (FLOT1) is a member of the flotillin family and serves as a hallmark of lipid rafts involved in the process of signaling transduction and vesicular trafficking. Here, we find FLOT1 promotes gastric cancer cell progression and metastasis by interacting with BCAR1, through ERK signaling. FLOT1 regulates BCAR1 phosphorylation and translocation. Overexpression of FLOT1 increases, while knockdown of FLOT1 decreases gastric cancer cell proliferation, migration and invasion. BCAR1 knockdown could block FLOT1 induced gastric cancer cell proliferation, migration and invasion. Re-expression of wildtype rather than mutant BCAR1 (Y410F) could partially restore FLOT1 knockdown induced gastric cancer cell migration and invasion, while the restore could be inhibited by ERK inhibitor. Furthermore, FLOT1 and BCAR1 expression is closely related to gastric cancer patients' poor outcome. Thus, our findings confirm that BCAR1 mediates FLOT1 induced gastric cancer progression and metastasis through ERK signaling, which may provide a novel pathway for gastric cancer treatment.

Flotillin-1 is a prognostic biomarker for glioblastoma and promotes cancer development through enhancing invasion and altering tumour microenvironment.

Flotillin-1(FLOT1) has long been recognized as a tumour-promoting gene in several types of cancer. However, the expression and function of FLOT1 in glioblastomas (GBM) has not been elucidated. Here, in this study, we find that the expression level of FLOT1 in GBM tissue was much higher than that in normal brain, and the expression was even higher in the more aggressive subtypes and IDH status of glioma. Kaplan-Meier survival revealed that high FLOT1 expression is closely associated with poor outcome in GBM patients. FLOT1 knockdown markedly reduced the proliferation, migration and invasiveness of GBM cells, while FLOT1 overexpression significantly increases GBM cell proliferation, migration and invasiveness. Mechanistically, FLOT1 expression may play a potential role in the microenvironment of GBM. Therefore, FLOT1 promotes GBM proliferation and invasion in vitro and in vivo and may serve as a biomarker of prognosis and therapeutic potential in the fight against GBM.

Downregulation of B3GNT6 is a predictor of poor outcomes in patients with colorectal cancer.

BACKGROUND: The B3GNT6 protein is a member of the O-GlcNAc transferase (OGT) family and is responsible for the production of the core 3 structure of O-glycans. It is generally expressed in the gastrointestinal (GI) tract; however, its clinical significance in colorectal cancer remains largely unexplored. METHODS: We obtained mRNA transcriptomic sequencing data from 3 gene expression omnibus (GEO) datasets (GSE37182, GSE39582, GSE103512) and The Cancer Genome Atlas (TCGA) to compare the B3GNT6 mRNA levels between colorectal cancer and normal tissues and further evaluate its value as a prognostic marker in colorectal cancer. We further validated this at the protein level in our cohort using immunohistochemical staining of B3GNT6 as well as the Human Protein Atlas online database. RESULTS: B3GNT6 expression was downregulated in colorectal cancer tissues as compared to that in the normal tissues at both mRNA and protein levels. Downregulation of B3GNT6 expression was found to be associated with poor overall survival in patients with colorectal cancer as per the data in GSE39582 and TCGA databases. Low B3GNT6 mRNA levels were significantly associated with chromosome instability (CIN) and KRAS mutations in patients with colorectal cancer. Gene set enrichment analysis (GSEA) revealed that low B3GNT6 expression levels in colorectal cancer were associated with increased proteasome activity. CONCLUSIONS: The results of this study demonstrate that low expression of B3GNT6 is a potential biomarker for poor outcomes in patients with CRC. Moreover, the low expression of B3GNT6 may indicate more frequent activation of the KRAS/ERK signaling pathway, high CIN, and increased proteasomal activity. These novel findings may prove helpful for molecular diagnosis and provide a new therapeutic target for colorectal cancer.

A Six-microRNA Signature Nomogram for Preoperative Prediction of Tumor Deposits in Colorectal Cancer.

PURPOSE: Tumor deposits (TDs) are acknowledged negative prognostic factors in colorectal cancer (CRC), and their pathogenesis remains a puzzle. This study aimed to construct and validate a nomogram available for preoperative TDs prediction in CRC patients. PATIENTS AND METHODS: Patients from the Surveillance, Epidemiology, and End Results (SEER) and the cancer genome atlas (TCGA) databases were randomly divided into training and validation sets according to the sample size ratio of 7:3. Univariate logistic regression was performed for identifying differentially expressed microRNAs between TDs and non-TDs. Nomograms for TDs prediction were developed from the multivariate logistic regression model with least absolute shrinkage and selection operator and were validated internally in terms of accuracy, calibration, and clinical utility. Based on the target genes, pathways tightly associated with TDs were selected using enrichment analysis. RESULTS: Six clinicopathologic factors and expressions of six microRNAs (miR-614, miR-1197, miR-4770, miR-3136, miR-3173, and miR-4636) differed significantly between TDs and non-TDs CRC patients from the SEER and TCGA training sets. We compared potential prediction discrimination between two nomograms: a clinicopathologic nomogram and a six-microRNA signature nomogram. The six-microRNA signature nomogram revealed better accuracy than the clinicopathologic one for TDs prediction (AUC values of 0.96 and 0.93 in the validation cohort). The calibration plots and decision curve analysis demonstrated that the six-microRNA signature nomogram had better validity and a greater prognostic benefit versus the clinicopathologic one for TDs prediction. Calcium signaling pathways were closely associated with roles of the six microRNAs in TDs of CRC patients. CONCLUSION: The six-microRNA signature nomogram can be used as an efficient tool for preoperative TDs prediction in CRC patients.

Prognostic relevance of neuroendocrine differentiation in colorectal cancer: a population-based, propensity score matching study.

PURPOSE: Neuroendocrine differentiation (NED) may serve as a prognostic factor in colorectal cancer; however, the prognostic relevance of NED remains controversial. The aim of the present study was to determine whether NED influenced the survival of patients in colorectal cancer while exploring its potential interactions with other clinicopathological features. METHODS: Patients with primary stage I to IV colorectal adenocarcinoma ranging between 2010 and 2015 were identified using the Surveillance, Epidemiology, and End Results database. The Kaplan-Meier technique, Cox proportional hazards model, propensity score matching, and stratification analyses were employed in this study. RESULTS: A total of 94,291 patients (including 101 patients with NED and 94,190 patients without NED) were included. In the univariable analyses, NED was found to be correlated with a significantly poorer overall survival (hazard ratio (HR) of death = 3.09, 95% CI 2.42-3.95, P < 0.001) and cancer-specific survival (HR of death = 3.77, 95% CI 2.94-4.83, P < 0.001). Moreover, NED remained independently correlated with overall survival (HR of death = 1.84, 95% CI 1.34-2.51, P < 0.001) and cancer-specific survival (HR of death = 2.01, 95% CI 1.45-2.79, P < 0.001) after adjusting in multivariable and propensity score analyses. Furthermore, further stratification analyses indicated that the influence of NED on survival was not affected by tumor location, differentiation, T stage, and distant metastasis status; however, it was found to be associated with lymph node metastasis. CONCLUSIONS: NED is associated with poor survival outcomes among colorectal cancer patients, especially in those with positive lymph nodes.

Nomogram predicting cancer-specific survival in elderly patients with stages I-III colon cancer.

Aim: This study aims to establish and validate an effective nomogram to predict cancer-specific survival (CSS) in elderly patients with stages I-III colon cancer.Methods: The data of elderly colon cancer patients with stages I-III were enrolled from the Surveillance, Epidemiology, and End Results database (SEER) between 2010 and 2015. The eligible patients were randomly divided into a training cohort and a validation cohort (ratio 1:1). All predictors of cancer-specific survival were determined by Cox regression. The concordance index (C-index) and calibration curves were used for validation of nomograms. Decision curve analysis (DCA) was performed to evaluate the clinical net benefit of the nomogram.Results: Cox hazard analysis in the training cohort indicated that grade, tumor stage, node stage, colectomy, and CEA were independent predictors of CSS. Nomogram was constructed based on these predictors. The C-index of nomograms for CSS was 0.728 (95%CI: 0.7133-0.7427), and were superior to that of AJCC TNM Stage (C-index: 0.625, 95%CI: 0.6093-0.6406). The calibration curves showed satisfactory consistency between actual observation and nomogram-predicted CSS probabilities. The validation cohort demonstrated similar results. The DCA showed high net benefit of nomogram in a clinical context. The population was divided into three groups based on the scores of the nomogram, and the survival analysis showed that this prognostic stratification was statistically significant (p < 0.01).Conclusion: The nomograms showed significant accuracy in predicting 1-, 3-, and 5-year CSS in elderly patients with stages I-III colon cancer and may be helpful inpatient counseling clinical decision guidance.