Identification of exosomal miR-484 role in reprogramming mitochondrial metabolism in pancreatic cancer through Wnt/MAPK axis control.

The microRNAs (miRNAs) are potent regulators of tumorigenesis in various cancers, especially pancreatic cancer. The abnormal expression of miRNAs can be observed in tumor cells. Noteworthy, miRNAs could be transferred by exosomes as small extracellular vesicles in regulation of carcinogenesis. This research focused on exploring the roles and mechanisms of exosomal miR-484, derived from human bone marrow mesenchymal stem cells (hBMSCs), in the context of molecular interactions and regulation of mitochondrial metabolism. Exosomes were isolated for the examination of miR-484 expression. The impacts of hBMSCs-derived exosomal miR-484 on pancreatic cancer cells were studied using various assays. Evaluation of mitochondrial function and metabolism was performed. Wnt/MAPK pathway-related protein expression was assessed, and an in vivo tumor xenograft model was utilized to examine the functions. Our findings demonstrated a decreased miR-484 expression in pancreatic cancer cells. However, hBMSCs-derived exosomal miR-484 inhibited the proliferation and migration of these cells, while inducing apoptosis. Moreover, miR-484 led to an upsurge in reactive oxygen species production, a decrease in ATP levels, and a disruption in mitochondrial metabolism. In vivo analyses showed that hBMSCs-derived exosomal miR-484 lessened tumor size and weight, while also suppressing the expression of mitochondrial biomarkers. Further, there was a decline in ß-catenin and p-p38 protein levels both in vitro and in vivo. The addition of LiCl restored the disrupted mitochondrial metabolism. Conclusively, our results suggest that hBMSCs-derived exosomal miR-484 mitigates the malignant transformation and mitochondrial metabolism of pancreatic cancer by deactivating the Wnt/MAPK pathway.

A pyroptosis-related gene signature predicts prognosis and immune microenvironment in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is a highly malignant tumor with a very poor prognosis. Pyroptosis is an inflammatory form of cell death and plays an important role in cancer development. The prognostic value of pyroptosis-related genes (PRGs) in HCC has not been studied extensively. METHODS: Unsupervised consensus clustering analysis was performed to identify two subtypes based on the expression profiles of prognostic PRGs in the The Cancer Genome Atlas (TCGA) database, and the differences between the two subtypes were compared. A prognostic model based on four PRGs was established by further least absolute shrinkage and selection operator (LASSO) Cox regression analysis and multivariate Cox regression analysis. RESULTS: Two subtypes (clusters 1 and 2) were identified by consensus clustering based on prognostic PRGs in HCC. Survival outcomes, biological function, genomic alterations, immune cell infiltration, and immune checkpoint genes were compared between the subtypes. Cluster 2 had a worse survival outcome than cluster 1. Cluster 2 was enriched for hallmarks of cancer progression, TP53 mutation, tumor-promoting immune cells, and immune checkpoint genes, which may contribute to the poor prognosis. A prognostic risk signature that predicted the overall survival (OS) of patients was constructed and validated. Consequently, a risk score was calculated for each patient. Combined with the clinical characteristics, the risk score was found to be an independent prognostic factor for survival of HCC patients. Further analysis revealed that the risk score was closely associated with the levels of immune cell infiltration and the expression profiles of immune checkpoint genes. CONCLUSIONS: Collectively, our study established a prognostic risk signature for HCC and revealed a significant correlation between pyroptosis and the HCC immune microenvironment.

Pancreatic cancer-derived exosomes induce apoptosis of T lymphocytes through the p38 MAPK-mediated endoplasmic reticulum stress.

Pancreatic cancer is the fourth most lethal malignancy and is characterized by poor immunogenicity. Pancreatic cancer cells have various strategies to suppress host immune response, evade immune defenses, and facilitate tumor growth and development. As a mode of long-range intercellular communication, cancer-derived exosomes contribute to impairment of the immune system. However, the mechanisms that induce changes in the activities of signal transduction pathways in immune cells, which are influenced by tumor-derived exosomes, are poorly understood. We (1) treated peripheral T lymphocytes with pancreatic cancer-derived exosomes, tagged CD63 with tdTomato, to trace exosome transfer from pancreatic cancer cells to T lymphocytes; (2) carried out a cytotoxicity assay of exosome-treated T lymphocytes using the Real Time Cellular Analysis system; (3) performed RNA sequencing and gene set enrichment analysis to explore the pivotal signaling pathway that mediates apoptosis in exosome-treated T lymphocytes; and (4) demonstrated the role of p38 mitogen-activated protein kinase (MAPK) and endoplasmic reticulum (ER) stress in exosome-induced T-lymphocyte apoptosis. In conclusion, these results indicate that pancreatic cancer cells secrete exosomes, which are taken up by T lymphocytes to activate p38 MAPK, and then induce ER stress-mediated apoptosis, ultimately causing immunosuppression.

Association of tooth loss and periodontal disease with all-cause mortality in cancer survivors: A cohort study based on NHANES.

Background: Increasing evidence supports the association between impaired oral health and elevated mortality. However, there is currently a lack of research on the impact of tooth loss and periodontal disease on survival outcomes in cancer survivors. This study aims to clarify the effect of tooth loss and periodontitis on all-cause mortality on cancer survivors. Methods: The clinical data of cancer survivors were collected from National Health and Nutrition Examination Survey (NHANES) 1999-2018. Mortality data were obtained by linking to records in the National Death Index until December 31, 2019. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal threshold for discriminating mortality based on the number of teeth lost. Kaplan-Meier survival curves and Cox regression analysis were performed to calculate hazard ratios (HRs) and 95 % confidence intervals (95 % CI) for tooth loss and periodontitis. Results: A total of 3271 cancer survivors were assessed for tooth loss status, while 1267 patients were evaluated for periodontitis status. The prevalence of any tooth loss and CDC-AAP periodontitis was 83.5 % and 47.2 %, respectively. The ROC curve showed the cut-off point of tooth loss for predicting mortality is > 5. Cancer survivors with tooth loss>5 had significantly lower bone density (1.06 vs. 1.13 g/cm2, P < 0.001), elevated C-reactive protein level (0.3 vs. 0.18 mg/dL, P < 0.001), and a trend of lower lean body mass (46.9 vs. 47.6 kg, P = 0.093). Besides, cancer survivors with severe periodontitis also exhibited elevated C-reactive protein level (0.34 vs. 0.21 mg/dL, P = 0.033). All-cause mortality significantly increased in cancer survivors with either tooth loss>5 (HR = 1.290, P = 0.001) or severe CDC-AAP periodontitis (HR = 1.682, P = 0.016) in the multivariate Cox regression analysis. Conclusion: Tooth loss and periodontitis are strong risk factors for reduced overall survival in cancer survivors. Cancer survivors should emphasize diligent oral hygiene and consistent dental check-ups to optimize long-term oral health. The causal relationship between oral health and survival rates in cancer survivors requires further validation through randomized controlled trials.

Diagnostic plasma small extracellular vesicles miRNA signatures for pancreatic cancer using machine learning methods.

BACKGROUND: Identifying biomarkers may lead to easier detection and a better understanding of pathogenesis of pancreatic ductal adenocarcinoma (PDAC). METHODS: Plasma small extracellular vesicles (sEV) from 106 participants, including 20 healthy controls (HC), 12 chronic pancreatitis (CP) patients, 12 benign pancreatic tumour (BPT) patients, and 58 PDAC patients, were profiled for microRNA (miRNA) sequencing. Three machine learning methods were applied to establish and evaluate the diagnostic model. RESULTS: The plasma sEV miRNA diagnostic signature (d-signature) selected using the three machine learning methods could distinguish PDAC patients from non-PDAC individuals, HC, and benign pancreatic disease (BPD, CP plus BPT) both in training and validation cohort. Combining the d-signature with carbohydrate antigen 19-9 (CA19-9) performed better than with each model alone. Plasma sEV miR-664a-3p was selected by all methods and used to predict PDAC diagnosis with high accuracy combined with CA19-9. Plasma sEV miR-664a-3p was significantly positively associated with the presence of vascular invasion, lower surgery ratio, and poor differentiation. MiR-664a-3p was mainly distributed in the PDAC cancer stroma, including fibers and vessels, and was accompanied by VEGFA expression. Overexpression of miR-664a-3p could promote the epithelial-mesenchymal transition (EMT) and angiogenesis. CONCLUSION: In conclusion, our study demonstrated the potential utility of the sEV-miRNA d-signature in the diagnosis of PDAC via machine learning methods. A novel sEV biomarker, miR-664a-3p, was identified for the diagnosis of PDAC. It can also potentially promote angiogenesis and metastasis, provide insight into PDAC pathogenesis, and reveal novel regulators of this disease.

Sirtuin4 impacts mitochondrial homeostasis in pancreatic cancer cells by reducing the stability of AlkB homolog 1 via deacetylation of the HRD1-SEL1L complex.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with a poor prognosis. As a tumor inhibitor, the specific tumor suppressor mechanism of Sirtuin4(SIRT4) in PDAC remains elusive. In this study, SIRT4 was found to inhibit PDAC by impacting mitochondrial homeostasis. SIRT4 deacetylated lysine 547 of SEL1L and increased the protein level of an E3 ubiquitin ligase HRD1. As a central member of ER-associated protein degradation (ERAD), HRD1-SEL1L complex is recently reported to regulate the mitochondria, though the mechanism is not fully delineated. Here, we found the increase in SEL1L-HRD1 complex decreased the stability of a mitochondrial protein, ALKBH1. Downregulation of ALKBH1 subsequently blocked the transcription of mitochondrial DNA-coded genes, and resulted in mitochondrial damage. Lastly, a putative SIRT4 stimulator, Entinostat, was identified, which upregulated the expression of SIRT4 and effectively inhibited pancreatic cancer in vivo and in vitro.

Elevated expression of exosomal microRNA-21 as a potential biomarker for the early diagnosis of pancreatic cancer using a tethered cationic lipoplex nanoparticle biochip.

Pancreatic cancer (PC) has a poor prognosis due to the lack of effective molecular biomarkers for early diagnosis. Recent studies have investigated the use of exosomal microRNAs (exmiRs) as diagnostic biomarkers in cancer. The present study examined exmiR-21, exmiR-10b and exmiR-212-3p expression in patients with PC and healthy individuals. The expression levels of exmiR-21, exmiR-10b and exmiR-212-3p were examined in the peripheral blood plasma of 36 patients with PC and 65 healthy controls, using tethered cationic lipoplex nanoparticle biochip. The levels of exmiR-21 in the plasma of 34 mice were also evaluated. The expression levels of exmiR-21 and exmiR-10b were significantly greater in patients with PC compared with the control group. The receiver operating characteristic (ROC) analysis indicated that exmiR-21 had better diagnostic performance (P=0.0003; AUC, 0.7171) compared with the other two exmiRs. The diagnostic value of exmiR-21 improved when combined with exmiR-10b (P<0.0001; AUC, 0.791). Furthermore, exmiR-21 was capable of distinguishing patients with early-stage PC from controls and advanced-stage PC (P<0.05, early stage vs. healthy; P<0.001, early stage vs. advanced stage). The results of the present study revealed that the plasma levels of exmiR-21 and exmiR-10b were upregulated in patients with PC. The ROC analyses indicated that exmiR-21 had the best diagnostic performance among the three exmiRs. Furthermore, exmiR-21 was capable of discriminating patients with early-stage PC from healthy controls. These findings indicate the potential of determining the expression of exmiR-21 from serum using a tethered cationic lipoplex nanoparticle biochip as a novel non-invasive strategy for the early diagnosis of PC.