Exosome-derived circUPF2 enhances resistance to targeted therapy by redeploying ferroptosis sensitivity in hepatocellular carcinoma.

BACKGROUND: Advanced hepatocellular carcinoma (HCC) can be treated with sorafenib, which is the primary choice for targeted therapy. Nevertheless, the effectiveness of sorafenib is greatly restricted due to resistance. Research has shown that exosomes and circular RNAs play a vital role in the cancer's malignant advancement. However, the significance of exosomal circular RNAs in the development of resistance to sorafenib in HCC remains uncertain. METHODS: Ultracentrifugation was utilized to isolate exosomes (Exo-SR) from the sorafenib-resistant HCC cells' culture medium. Transcriptome sequencing and differential expression gene analysis were used to identify the targets of Exo-SR action in HCC cells. To identify the targets of Exo-SR action in HCC cells, transcriptome sequencing and analysis of differential expression genes were employed. To evaluate the impact of exosomal circUPF2 on resistance to sorafenib in HCC, experiments involving gain-of-function and loss-of-function were conducted. RNA pull-down assays and mass spectrometry analysis were performed to identify the RNA-binding proteins interacting with circUPF2. RNA immunoprecipitation (RIP), RNA pull-down, electrophoretic mobility shift assay (EMSA), immunofluorescence (IF) -fluorescence in situ hybridization (FISH), and rescue assays were used to validate the interactions among circUPF2, IGF2BP2 and SLC7A11. Finally, a tumor xenograft assay was used to examine the biological functions and underlying mechanisms of Exo-SR and circUPF2 in vivo. RESULTS: A novel exosomal circRNA, circUPF2, was identified and revealed to be significantly enriched in Exo-SR. Exosomes with enriched circUPF2 enhanced sorafenib resistance by promoting SLC7A11 expression and suppressing ferroptosis in HCC cells. Mechanistically, circUPF2 acts as a framework to enhance the creation of the circUPF2-IGF2BP2-SLC7A11 ternary complex contributing to the stabilization of SLC7A11 mRNA. Consequently, exosomal circUPF2 promotes SLC7A11 expression and enhances the function of system Xc- in HCC cells, leading to decreased sensitivity to ferroptosis and resistance to sorafenib. CONCLUSIONS: The resistance to sorafenib in HCC is facilitated by the exosomal circUPF2, which promotes the formation of the circUPF2-IGF2BP2-SLC7A11 ternary complex and increases the stability of SLC7A11 mRNA. Focusing on exosomal circUPF2 could potentially be an innovative approach for HCC treatment.

Exosomal circTGFBR2 promotes hepatocellular carcinoma progression via enhancing ATG5 mediated protective autophagy.

Exosomes contribute substantially to the communication between tumor cells and normal cells. Benefiting from the stable structure, circular RNAs (circRNAs) are believed to serve an important function in exosome-mediated intercellular communication. Here, we focused on circRNAs enriched in starvation-stressed hepatocytic exosomes and further investigated their function and mechanism in hepatocellular carcinoma (HCC) progression. Differentially expressed circRNAs in exosomes were identified by RNA sequencing, and circTGFBR2 was identified and chosen for further study. The molecular mechanism of circTGFBR2 in HCC was demonstrated by RNA pulldown, RIP, dual-luciferase reporter assays, rescue experiments and tumor xenograft assay both in vitro and vivo. We confirmed exosomes with enriched circTGFBR2 led to an upregulated resistance of HCC cells to starvation stress. Mechanistically, circTGFBR2 delivered into HCC cells via exosomes serves as a competing endogenous RNA by binding miR-205-5p to facilitate ATG5 expression and enhance autophagy in HCC cells, resulting in resistance to starvation. Thus, we revealed that circTGFBR2 is a novel tumor promoter circRNA in hepatocytic exosomes and promotes HCC progression by enhancing ATG5-mediated protective autophagy via the circTGFBR2/miR-205-5p/ATG5 axis, which may be a potential therapeutic target for HCC.

Diagnosing sentinel lymph node metastasis of T1/T2 breast cancer with conventional ultrasound combined with double contrast-enhanced ultrasound: a preliminary study.

Background: In patients with T1/T2 breast cancer (BC), sentinel lymph node (SLN) status is essential for prognosis and treatment. This study investigated the value of conventional ultrasound combined with double contrast-enhanced ultrasound in diagnosing the metastasis of SLNs in patients with T1/T2 BC. Methods: This study employed a prospective design (this diagnostic study was not registered on a clinical trial platform), and the participants formed a convenience series. Based on the inclusion and exclusion criteria, 163 patients with BC who received treatment in the First Affiliated Hospital of Soochow University from July 2017 to December 2021 were included in this study. A total of 165 SLNs from 163 patients with T1/T2 BC were analyzed. All patients underwent percutaneous contrast-enhanced ultrasound (PCEUS) to trace SLNs before the operation. Subsequently, all patients underwent conventional ultrasound and intravenous contrast-enhanced ultrasound (ICEUS) examinations to observe the SLNs. The results of the conventional ultrasound, ICEUS, and PCEUS of the SLNs were analyzed. The associations between the risk of SLN metastasis and imaging features were evaluated via a nomogram based on the pathological results. Results: Overall, 54 metastatic SLNs and 111 nonmetastatic SLNs were evaluated. Metastatic SLNs displayed a greater cortical thickness, area ratio, eccentric fatty hilum, and hybrid blood flow on conventional ultrasound compared with nonmetastatic SLNs (P<0.001). According to PCEUS, 75.93% of metastatic SLNs showed heterogeneous enhancement (type II and III), and 73.88% of nonmetastatic SLNs showed homogeneous enhancement (type I; P<0.001). According to ICEUS, heterogeneous enhancement (type B/C, 20.37% vs. 11.71%) and overall enhancement (55.56% vs. 23.42%) were more common in metastatic SLNs than in nonmetastatic SLNs (P<0.001). Logistic regression analysis showed that the cortical thickness and enhancement type of PCEUS were independent predictors of SLN metastasis. Moreover, a nomogram combining these factors showed a high diagnostic ability for SLN metastasis (unadjusted concordance index 0.860, 95% CI: 0.730-0.990; bootstrap-corrected concordance index 0.853). Conclusions: The nomogram of cortical thickness and enhancement type of PCEUS could effectively diagnose SLN metastasis in patients with T1/T2 BC.

Value of contrast-enhanced ultrasound area ratio in identifying benign and malignant small breast masses.

BACKGROUND: Tumor size affects clinical staging and is closely related to prognosis. Therefore, early diagnosis of breast cancer is one of the most important methods to reduce mortality and improve prognosis. However, minimal breast cancer is difficult to differentiate from small benign breast masses due to insufficient typical malignant signs. The significantly increased range of enhancement can be an important indication for the prediction of malignancy; however, quantitative studies on the extent of enhancement are rarely reported. The purpose of this study was to investigate the value of contrast-enhanced ultrasound (CEUS) area ratio in finding benign and malignant small breast masses. METHODS: A retrospective analysis was conducted on 88 patients with breast masses confirmed by surgery or needle biopsy (the maximal diameter not over 1 cm). 88 breast masses were divided into the younger age group (not over 40 years old) and older age group (over 40 years old) according to the patient's age. The receiver operating characteristic (ROC) curve was used to determine the cutoff values of CEUS area ratio in diagnosing benign or malignant small breast masses in each group. The efficiency of different cutoff values in finding benign and malignant small breast masses of the distinct groups was analyzed. RESULTS: The CEUS area ratio of malignant mass was larger than benign masses (P<0.05). The CEUS area ratio of malignant masses in the younger age group was larger than that in the older age group (P<0.05). The results of the ROC curve analysis showed that the area under the curve (AUC) and the cutoff values of the entire group, the younger age group, and the older age group were 0.887, 1.65; 0.909, 1.95; and 0.908, 1.22, respectively. When the cutoff value of the older age group was reduced from 1.65 to 1.22, its diagnostic sensitivity was improved significantly (P<0.05). CONCLUSIONS: CEUS area ratio has specific application value in finding benign and malignant small breast masses. Proper reduction of the cutoff value of elderly patients can further improve its diagnostic sensitivity without significantly reducing the specificity.

Suppression of the Epidermal Growth Factor-like Domain 7 and Inhibition of Migration and Epithelial-Mesenchymal Transition in Human Pancreatic Cancer PANC-1 Cells.

BACKGROUND: Epidermal growth factor-like domain multiple 7 (EGFL7), a secreted protein specifically expressed by endothelial cells during embryogenesis, recently was identified as a critical gene in tumor metastasis. Epithelial-mesenchymal transition (EMT) was found to be closely related with tumor progression. Accordingly, it is important to investigate the migration and EMT change after knock-down of EGFL7 gene expression in human pancreatic cancer cells. MATERIALS AND METHODS: EGFL7 expression was firstly testified in 4 pancreatic cancer cell lines by real-time polymerase chain reaction (Real-time PCR) and western blot, and the highest expression of EGFL7 was found in PANC-1 cell line. Then, PANC-1 cells transfected with small interference RNA (siRNA) of EGFL7 using plasmid vector were named si-PANC-1, while transfected with negative control plasmid vector were called NC-PANC-1. Transwell assay was used to analyze the migration of PANC-1 cells. Real-time PCR and western blotting were used to detect the expression change of EGFL7 gene, EMT markers like E-Cadherin, N-Cadherin, Vimentin, Fibronectin and transcription factors like snail, slug in PANC-1, NC- PANC-1, and si-PANC-1 cells, respectively. RESULTS: After successful plasmid transfection, EGFL7 gene were dramatically knock-down by RNA interference in si-PANC-1 group. Meanwhile, migration ability decreased significantly, compared with PANC-1 and NC-PANC-1 group. Meanwhile, the expression of epithelial phenotype marker E-Cadherin increased and that of mesenchymal phenotype markers N-Cadherin, Vimentin, Fibronectin dramatically decreased in si-PANC-1 group, indicating a reversion of EMT. Also, transcription factors snail and slug decreased significantly after RNA interference. CONCLUSIONS: Current study suggested that highly-expressed EGFL7 promotes migration of PANC-1 cells and acts through transcription factors snail and slug to induce EMT, and further study is needed to confirm this issue.