Hepatocyte-derived exosomal MiR-194 activates PMVECs and promotes angiogenesis in hepatopulmonary syndrome

Elevated circulating BMP9 aggravates pulmonary angiogenesis in hepatopulmonary syndrome rats through ALK1-Endoglin-Smad1/5/9 signalling

BACKGROUND

Bone morphogenetic protein 9 (BMP9) is a hepatokine that plays a pivotal role in the progression of liver diseases. Moreover, an increasing number of studies have shown that BMP9 is associated with hepatopulmonary syndrome (HPS), but its role in HPS is unclear. Here, we evaluated the influence of CBDL on BMP9 expression and investigated potential mechanisms of BMP9 signalling in HPS.

METHODS

We profiled the circulating BMP9 levels in common bile duct ligation-induced HPS rat model, and then investigated the effects and mechanisms of HPS rat serum on pulmonary vascular endothelial dysfunction in rat model, as well as in primarily cultured rat pulmonary microvascular endothelial cells.

RESULTS

Our data revealed that circulating BMP9 levels were significantly increased in the HPS rats compared to control group. Besides, the elevated BMP9 in HPS rat serum was not only crucial for promoting endothelial cell proliferation and tube formation through the activin receptor-like kinase1 (ALK1)-Endoglin-Smad1/5/9 pathway, but also important for accumulation of monocytes. Treatments with ALK1-Fc or silencing ALK1 expression to inhibit the BMP9 signalling pathway effectively eliminated these effects. In agreement with these observations, increased circulating BMP9 was associated with an increase in lung vessel density and accumulation of pro-angiogenic monocytes in the microvasculature in HPS rats.

CONCLUSIONS

This study provided evidence that elevated circulating BMP9, secreted from the liver, promote pulmonary angiogenesis in HPS rats via ALK1-Endoglin-Smad1/5/9 pathway. In addition, BMP9-regulated pathways are also involved in accumulation of pro-angiogenic monocytes in the pulmonary microvasculature in HPS rats.

Fractalkine modulates pulmonary angiogenesis and tube formation by modulating CX3CR1 and growth factors in PVECs

This study aimed to investigate effects of pulmonary fractalkine (FKN/CX3CL1) on angiogenesis and tube formation. Tube forming capability of pulmonary vascular endothelial cells (PVECs) was evaluated. CCK-8 assay was used to evaluate proliferation of PVECs. RT-PCR assay was used to determine angiogenesis specific biomarkers. Western blot was applied to identify CX3CR1, Akt, phosphorylated Akt (p-Akt), Erk1/2, phosphorylated Erk1/2 (p-Erk1/2), vascular endothelial growth factor A (VEGFA), and inducible nitric oxide synthase (iNOS) expression. VEGF-A and platelet-derived growth factor (PDGF) levels were examined using ELISA. FKN was safe and triggered tube formation in PVECs. FKN significantly enhanced VEGF-A, PDGF, and iNOS gene transcription compared to the Control group (p < 0.05). CX3CR1 interfering (LV5-CX3CR1 shRNA) remarkably reduced CX3CR1 expression compared to those in LV5 blank group (p < 0.05). Ratios of p-Akt/Akt and p-Erk/Erk were significantly decreased in CX3CR1 shRNA-treated PVECs administered Akt inhibitor (or Erk inhibitor) and 10 ng/mL FKN compared to CX3CR1 shRNA-treated PVECs administered 10 ng/mL FKN (p < 0.05). FKN increased VEGF-A and iNOS expression through activating Akt/Erk pathway. FKN promoted VEGF-A/iNOS expression and triggered p-Akt/Akt and p-Erk/Erk pathway through modulating CX3CR1. FKN-treated macrophages enhanced activation of Akt/Erk pathway. FKN-treated macrophages enhanced PDGF and VEGF-1 expression in PVECs. FKN modulated pulmonary angiogenesis and tube formation through modulating CX3CR1 and growth factors and activating p-Akt/Akt and p-Erk/Erk signaling pathway.

Emerging Evidence Linking the Liver to the Cardiovascular System: Liver-derived Secretory Factors

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality worldwide. Recently, accumulating evidence has revealed hepatic mediators, termed as liver-derived secretory factors (LDSFs), play an important role in regulating CVDs such as atherosclerosis, coronary artery disease, thrombosis, myocardial infarction, heart failure, metabolic cardiomyopathy, arterial hypertension, and pulmonary hypertension. LDSFs presented here consisted of microbial metabolite, extracellular vesicles, proteins, and microRNA, they are primarily or exclusively synthesized and released by the liver, and have been shown to exert pleiotropic actions on cardiovascular system. LDSFs mainly target vascular endothelial cell, vascular smooth muscle cells, cardiomyocytes, fibroblasts, macrophages and platelets, and further modulate endothelial nitric oxide synthase/nitric oxide, endothelial function, energy metabolism, inflammation, oxidative stress, and dystrophic calcification. Although some LDSFs are known to be detrimental/beneficial, controversial findings were also reported for many. Therefore, more studies are required to further explore the causal relationships between LDSFs and CVDs and uncover the exact mechanisms, which is expected to extend our understanding of the crosstalk between the liver and cardiovascular system and identify potential therapeutic targets. Furthermore, in the case of patients with liver disease, awareness should be given to the implications of these abnormalities in the cardiovascular system. These studies also underline the importance of early recognition and intervention of liver abnormalities in the practice of cardiovascular care, and a multidisciplinary approach combining hepatologists and cardiologists would be more preferable for such patients.

Serum Soluble Vascular Endothelial Growth Factor Receptor 1 as a Potential Biomarker of Hepatopulmonary Syndrome

Background and Aims

The results of basic research implicate the vascular endothelial growth factor (VEGF) family as a potential target of hepatopulmonary syndrome (HPS). However, the negative results of anti-angiogenetic therapy in clinical studies have highlighted the need for markers for HPS. Therefore, we aimed to determine whether VEGF family members and their receptors can be potential biomarkers for HPS through clinical and experimental studies.

Methods

Clinically, patients with chronic liver disease from two medical centers were enrolled and examined for HPS. Patients were divided into HPS, intrapulmonary vascular dilation [positive contrast-enhanced echocardiography (CEE) and normal oxygenation] and CEE-negative groups. Baseline information and perioperative clinical data were compared between HPS and non-HPS patients. Serum levels of VEGF family members and their receptors were measured. In parallel, HPS rats were established by common bile duct ligation. Liver, lung and serum samples were collected for the evaluation of pathophysiologic changes, as well as the expression levels of the above factors.

Results

In HPS rats, all VEGF family members and their receptors underwent significant changes; however, only soluble VEGFR1 (sFlt-1) and the sFlt-1/ placental growth factor (PLGF) ratio were changed in almost the same manner as those in HPS patients. Furthermore, through feature selection and internal and external validation, sFlt-1 and the sFlt-1/PLGF ratio were identified as the most important variables to distinguish HPS from non-HPS patients.

Conclusions

Our results from animal and human studies indicate that sFlt-1 and the sFlt-1/PLGF ratio in serum are potential markers for HPS.

Vascular Extracellular Vesicles Indicate Severe Hepatopulmonary Syndrome in Cirrhosis

Background: Hepatopulmonary syndrome (HPS) is a pulmonary vasculature complication in the setting of liver disease that is characterized by pathological vasodilation resulting in arterial oxygenation defects. We investigated the role of extracellular vesicles (EV) in cirrhosis patients with HPS, as well as the functional effect of EV administration in a common bile duct ligation (CBDL) HPS mouse model. Methods: A total of 113 cirrhosis patients were studied: 42 (Gr. A) with HPS and 71 (Gr. B) without HPS, as well as 22 healthy controls. Plasma levels of EV associated with endothelial cells, epithelial cells, and hepatocytes were measured. The cytokine cargoes were estimated using ELISA. The effect of EV administered intranasally in the CBDL mouse model was investigated for its functional effect in vascular remodeling and inflammation. Results: We found endothelial cells (EC) associated EV (EC-EV) were elevated in cirrhosis patients with and without HPS (p < 0.001) than controls. EC-EV levels were higher in HPS patients (p = 0.004) than in those without HPS. The epithelial cell EVs were significantly high in cirrhosis patients than controls (p < 0.001) but no changes found in patients with HPS than without. There was a progressive increase in EC-EV levels from mild to severe intrapulmonary shunting in HPS patients (p = 0.02 mild vs. severe), and we were able to predict severe HPS with an AUROC of 0.85; p < 0.001. An inverse correlation of EC-EVs was found with hemoglobin (r = −0.24; p = 0.031) and PaO2 (r = 0.690; p = 0.01) and a direct correlation with MELD (r = 0.32; p = 0.014). Further, both TNF-α (p = 0.001) and IL-1β (p = 0.021) as cargo levels were significantly elevated inside the EVs of HPS patients than without HPS. Interestingly, upon administration of intranasal EVs, there was a significant decrease in Evans blue accumulation and lung wet–dry ratio (p = 0.042; 0.038). A significant reduction was also noticed in inflammation and cholestasis. Conclusion: High levels of plasma EC-EV levels were found in patients with HPS with elevated pro-inflammatory cytokine cargoes. EC-EVs were indicative of severe HPS condition. In the CBDL HPS model, we were able to prove the beneficial effects of improving vascular tone, inflammation, and liver pathogenesis.

Systemic Metabolic Alteration Dependent on the Thyroid-Liver Axis in Early PD

OBJECTIVE

Parkinson's disease (PD) is a common neurodegenerative disease characterized by initial involvement of the olfactory bulb/amygdala or autonomic nerves followed by nigral degeneration. Although autonomic innervation strictly regulates multiorgan systems, including endocrine functions, circulation, and digestion, how dysautonomia in PD affects systemic metabolism has not been identified. In this study, we tried to estimate the pathogenic linkage of PD by nuclear medicine techniques, trans-omic analysis of blood samples, and cultured cell experiments.

METHODS

Thyroid mediastinum ratio of ¹²³ I-metaiodobenzylguanidine (MIBG) scintigraphy was measured in 1,158 patients with PD. Furthermore, serum exosome miRNA transcriptome analysis and plasma metabolome analysis followed by trans-omic analysis were performed in patients with de novo PD and age-matched healthy control persons. Additionally, thyroid hormone was administered to skeletal muscle and liver derived cells to evaluate the effect of hypothyroidism for these organs.

RESULTS

Sympathetic denervation of thyroid correlating with its cardiac denervation was confirmed in 1,158 patients with PD by MIBG scintigraphy. Among patients with drug-naïve PD, comprehensive metabolome analysis revealed decreased levels of thyroxine and insufficient fatty acid β-oxidation, which positively correlate with one another. Likewise, both plasma metabolome data and transcriptome data of circulating exosomal miRNAs, revealed specific enrichment of the peroxisome proliferator-activated receptor (PPARα) axis. Finally, association of thyroid hormone with PPARα-dependent β-oxidation regulation was confirmed by in vitro experiments.

INTERPRETATION

Our findings suggest that interorgan communications between the thyroid and liver are disorganized in the early stage of PD, which would be a sensitive diagnostic biomarker for PD. ANN NEUROL 2023;93:303-316.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

Endothelial glycocalyx in hepatopulmonary syndrome: An indispensable player mediating vascular changes

Hepatopulmonary syndrome (HPS) is a serious pulmonary vascular complication that causes respiratory insufficiency in patients with chronic liver diseases. HPS is characterized by two central pathogenic features-intrapulmonary vascular dilatation (IPVD) and angiogenesis. Endothelial glycocalyx (eGCX) is a gel-like layer covering the luminal surface of blood vessels which is involved in a variety of physiological and pathophysiological processes including controlling vascular tone and angiogenesis. In terms of lung disorders, it has been well established that eGCX contributes to dysregulated vascular contraction and impaired blood-gas barrier and fluid clearance, and thus might underlie the pathogenesis of HPS. Additionally, pharmacological interventions targeting eGCX are dramatically on the rise. In this review, we aim to elucidate the potential role of eGCX in IPVD and angiogenesis and describe the possible degradation-reconstitution equilibrium of eGCX during HPS through a highlight of recent literature. These studies strongly underscore the therapeutic rationale in targeting eGCX for the treatment of HPS.

miR-18a-5p Reduces Inflammatory Response and Human Dermal Microvascular Endothelial Cells Permeability by Targeting Thrombospondin 1 in Chronic Idiopathic Urticaria

Chronic idiopathic urticaria (CIU) is a skin disease that has an acute attack when patient encounters an allergen. Previous research demonstrated that microRNA (miRNA) has a crucial role in CIU occurrence and development. This study aimed to investigate the role and mechanism of miR-18a-5p in CIU. StarBase and dual luciferase reporter gene assay confirmed that thrombospondin 1 (THBS1) was a direct target of miR-18a-5p. miR-18a-5p negatively regulated THBS1 expression in human mast cell line HMC-1 and human dermal microvascular endothelial cells (HDMECs). Further analysis indicated that miR-18a-5p mimic significantly reduced inflammatory factors including interleukin (IL)-6, IL-8, IL-1β and tumor necrosis factor (TNF)-α release, decreased the degranulation rate and histamine release rate of HMC-1 cells. Besides, we found that miR-18a-5p reduced the permeability of HDMECs by suppressing THBS1 expression. Finally, the data indicated that miR-18a-5p inhibited the transforming growth factor beta (TGF-β)/SMAD family member 3 (Smad3) signaling pathway in HDMECs by inhibiting the expression of THBS1. Taken together, the results suggested that miR-18a-5p reduced inflammation and human skin microvascular endothelial cell permeability in CIU by targeting THBS1. miR-18a-5p might be a new target for CIU treatment.

Circulating Extracellular Vesicles Contain Liver-Derived RNA Species as Indicators of Severe Cholestasis-Induced Early Liver Fibrosis in Mice

Aims: Biliary diseases represent around 10% of all chronic liver diseases and affect both adults and children. Currently available biochemical tests detect cholestasis but not early liver fibrosis. Circulating extracellular vesicles (EVs) provide a noninvasive, real-time molecular snapshot of the injured organ. We thus aimed at searching for a panel of EV-based biomarkers for cholestasis-induced early liver fibrosis using mouse models. Results: Progressive and detectable histological evidence of collagen deposition and liver fibrosis was observed from day 8 after bile duct ligation (BDL) in mice. Whole transcriptome and small RNA sequencing analyses of circulating EVs revealed differentially enriched RNA species after BDL versus sham controls. Unsupervised hierarchical clustering identified a signature that allowed for discrimination between BDL and controls. In particular, 151 microRNAs (miRNAs) enriched in BDL-derived EVs were identified, of which 66 were conserved in humans. The liver was an important source of circulating EVs in BDL animals as evidenced by the enrichment of several hepatic mRNAs, such as Albumin and Haptoglobin. Interestingly, among experimentally validated miRNAs, miR192-5p, miR194-5p, miR22-3p, and miR29a-3p showed similar enrichment patterns also in EVs derived from 3,5-diethoxycarboncyl-1,4-dihydrocollidine-treated (drug-induced severe cholestasis) but not in mice with mild phenotype or non-cholestatic liver fibrosis. Innovation: A panel of mRNAs and miRNAs contained in circulating EVs, when combined, indicates hepatic damage and fibrosis in mice and represents promising biomarkers for human severe cholestasis-induced liver fibrosis. Conclusion: Analysis of EV-based miRNAs, in combination with hepatic injury RNA markers, can detect early cholestatic liver injury and fibrosis in mice. Antioxid. Redox Signal. 36, 480-504.

Loss of hepatic miR-194 promotes liver regeneration and protects from acetaminophen-induced acute liver injury

The two microRNAs miR-192 and miR-194 are abundantly expressed in the liver and are considered serum biomarkers of liver injury. However, their role in the development of liver injury has not yet been determined. In this study, we generated miR-192/194 mutant mice and determined the effect of miR-192/194 loss on acetaminophen (APAP)-induced acute liver injury. With genetic depletion of miR-192/194, mutant mice were fertile and normally developed. No spontaneous liver injuries were observed in mutant mice. After APAP administration, mutant mice developed less severe liver damage than control mice. Specifically, mutant mice exhibited significantly lower serum alanine transaminase (ALT) levels and pericentral necrosis/apoptosis than control mice receiving APAP. β-catenin signaling was activated during the early phase of liver injury. Activated β-catenin signaling led to faster cellular proliferation and higher expression of AXIN2 and glutamine synthetases. After partial hepatectomy, the miR-192/194 mutant hepatocytes were more regenerative than control hepatocytes (as shown by BrdU incorporation). Moreover, in vitro experiments indicated that miR-194, but not miR-192, specifically repressed β-catenin signaling, while animal experiments revealed that chemical-mediated knockdown of β-catenin signaling compromised APAP resistance that liver protected from miR-192/194 genetic depletion. Collectively, our data indicated that the loss of miR-194 promoted liver regeneration and protected the liver from APAP-induced injury.

Role of extracellular vesicles in liver diseases and their therapeutic potential

More than eight hundred million people worldwide have chronic liver disease, with two million deaths per year. Recurring liver injury results in fibrogenesis, progressing towards cirrhosis, for which there doesn't exists any cure except liver transplantation. Better understanding of the mechanisms leading to cirrhosis and its complications is needed to develop effective therapies. Extracellular vesicles (EVs) are released by cells and are important for cell-to-cell communication. EVs have been reported to be involved in homeostasis maintenance, as well as in liver diseases. In this review, we present current knowledge on the role of EVs in non-alcoholic fatty liver disease and non-alcoholic steatohepatitis, alcohol-associated liver disease, chronic viral hepatitis, primary liver cancers, acute liver injury and liver regeneration. Moreover, therapeutic strategies involving EVs as targets or as tools to treat liver diseases are summarized.

Baseline serum exosome-derived miRNAs predict HBeAg seroconversion in chronic hepatitis B patients treated with peginterferon

This study aimed to explore the value of baseline serum exosome-derived miRNAs for predicting HBeAg seroconversion in chronic hepatitis B (CHB) patients treated with peginterferon (Peg-IFN). A total of 120 treatment-naïve HBeAg-positive CHB patients who received Peg-IFN therapy (48 weeks) were enrolled. Next-generation sequencing was performed to screen the serum exosomal miRNAs that were associated with Peg-IFN treatment outcome, and qRT-PCR was used to validate them. The area under the receiver operating characteristic curve (AUROC) was used to evaluate the predictive efficacy of biomarkers. Thirty-three patients (27.5%) achieved HBeAg seroconversion (response group), and 87 patients (72.5%) did not achieve HBeAg seroconversion (nonresponse group). In the identification cohort, 40 serum exosome-derived miRNAs were differentially expressed between the response group (four patients) and the nonresponse group (four patients). In the confirmation cohort, the expression levels of serum exosomal miR-194-5p (p < .001) and miR-22-3p (p < .001) were significantly downregulated in the response group (29 patients) compared to the nonresponse group (83 patients). Multivariate analysis identified baseline serum exosomal miR-194-5p, miR-22-3p, alanine aminotransferase (ALT), and HBV DNA as independent predictors of HBeAg seroconversion (all p < .05). The AUROCs of serum exosomal miRNAs (0.77 and 0.75 for miR-194-5p and miR-22-3p, respectively) were higher than that of ALT (0.70) and HBV DNA (0.69). The combination of exosomal miR-194-5p and miR-22-3p further improved the predictive performance with an AUROC of 0.82. Baseline serum exosomal miR-194-5p and miR-22-3p may serve as novel biomarkers to predict HBeAg seroconversion in CHB patients treated with Peg-IFN.

Tumor microenvironment pathways: Cross regulation in breast cancer metastasis

The tumor microenvironment (TME) is heterogeneous and contains a multiple cell population with surrounded immune cells, which plays a major role in regulating metastasis. The multifunctional pathways, Hedgehog (Hh), Wnt, Notch, and NF-kB, cross-regulates metastasis in breast cancer. This review presents substantial evidence for cross-regulation of TME components and signaling pathways, which makes breast TME more heterogeneous and complex, promoting breast cancer progression and metastasis as a highly aggressive form. We discoursed the importance of stromal and immune cells as well as their crosstalk in bridging the metastasis. We also discussed the role of Hh and Notch pathways in the intervention between breast cancer cells and macrophages to support TME; Notch signaling in the bidirectional communication between cancer cells and components of TME; Wnt signal pathway in controlling the factors responsible for EMT and NF-κB pathway in the regulation of genes controlling the inflammatory response. We also present the role of exosomes and their miRNAs in the cross-regulation of TME cells as well as pathways in the reprogramming of breast TME to support metastasis. Finally, we examined and discussed the targeted small molecule inhibitors and natural compounds targeting developmental pathways and proposed small molecule natural compounds as potential therapeutics of TME based on the multitargeting ability. In conclusion, the understanding of the molecular basis of the cross-regulation of TME pathways and their inhibitors helps identify molecular targets for rational drug discovery to treat breast cancers.

Linc-ROR promotes the progression of breast cancer and decreases the sensitivity to rapamycin through miR-194-3p targeting MECP2

linc‐ROR is reported to be a potential biomarker of breast cancer, but the detailed mechanism of linc‐ROR‐mediated breast cancer regulation has not been fully studied. We aimed to explore how linc‐ROR affects proliferation, metastasis, and drug sensitivity in breast cancer. Cell lines in which linc‐ROR was overexpressed or knocked down were constructed, and the cell proliferation, colony formation, cell migration, and invasion abilities of these lines were explored. A CCK‐8 assay was performed to determine the sensitivity of the breast cancer cells to rapamycin. Next‐generation sequencing was conducted to explore the detailed regulatory mechanism of linc‐ROR; differentially expressed RNAs in the linc‐ROR‐overexpressing cell line compared with the negative control were screened out, and their target genes were chosen to perform Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis, protein–protein interaction network analysis, and competing endogenous RNA (ceRNA) network analysis. The ceRNA mechanism of linc‐ROR for miR‐194‐3p, which targets MECP2, was determined through dual‐luciferase reporter assay, RT–qPCR, western blot, and rescue experiments. Finally, we found that linc‐ROR was upregulated in breast tumor tissues. linc‐ROR promoted the cell proliferation, colony formation, cell migration, and invasion of breast cancer and decreased the sensitivity of breast cancer cells to rapamycin. The overexpression of linc‐ROR triggered changes in the whole transcriptome of breast cancer cells, and a total of 85 lncRNAs, 414 microRNAs, 490 mRNAs, and 92 circRNAs were differentially expressed in the linc‐ROR‐overexpressing cell line compared with the negative control. Through a series of bioinformatic analyses, the ‘linc‐ROR/miR‐194‐3p/MECP2’ ceRNA regulatory axis was confirmed to be involved in the linc‐ROR‐mediated progression and drug sensitivity of breast cancer. In conclusion, linc‐ROR serves as an onco‐lncRNA in breast cancer and promotes the survival of breast cancer cells during rapamycin treatment by functioning as a ceRNA sponge for miR‐194‐3p, which targets MECP2.

Dying tumor cell-derived exosomal miR-194-5p potentiates survival and repopulation of tumor repopulating cells upon radiotherapy in pancreatic cancer

BACKGROUND

Tumor repopulation is a major cause of radiotherapy failure. Previous investigations highlighted that dying tumor cells played vital roles in tumor repopulation through promoting proliferation of the residual tumor repopulating cells (TRCs). However, TRCs also suffer DNA damage after radiotherapy, and might undergo mitotic catastrophe under the stimulation of proliferative factors released by dying cells. Hence, we intend to find out how these paradoxical biological processes coordinated to potentiate tumor repopulation after radiotherapy.

METHODS

Tumor repopulation models in vitro and in vivo were used for evaluating the therapy response and dissecting underlying mechanisms. RNA-seq was performed to find out the signaling changes and identify the significantly changed miRNAs. qPCR, western blot, IHC, FACS, colony formation assay, etc. were carried out to analyze the molecules and cells.

RESULTS

Exosomes derived from dying tumor cells induced G1/S arrest and promoted DNA damage response to potentiate survival of TRCs through delivering miR-194-5p, which further modulated E2F3 expression. Moreover, exosomal miR-194-5p alleviated the harmful effects of oncogenic HMGA2 under radiotherapy. After a latent time, dying tumor cells further released a large amount of PGE2 to boost proliferation of the recovered TRCs, and orchestrated the repopulation cascades. Of note, low-dose aspirin was found to suppress pancreatic cancer repopulation upon radiation via inhibiting secretion of exosomes and PGE2.

CONCLUSION

Exosomal miR-194-5p enhanced DNA damage response in TRCs to potentiate tumor repopulation. Combined use of aspirin and radiotherapy might benefit pancreatic cancer patients.