Disrupting of IGF2BP3-stabilized HK2 mRNA by MYO16-AS1 competitively binding impairs LUAD migration and invasion.

Since invasive cancer is associated with poor clinical outcomes, exploring the molecular mechanism underlying LUAD progression is crucial to improve the prognosis of patients with advanced disease. Herein, we found that MYO16-AS1 is expressed mainly in lung tissue but is notably downregulated in LUAD tissues. Overexpression of MYO16-AS1 inhibited the migration and invasion of LUAD cells. Mechanistic studies indicated that H3K27Ac modification mediated MYO16-AS1 transcription. Furthermore, we found that MYO16-AS1 competitively bound to the IGF2BP3 protein and in turn reduced IGF2BP3 protein binding to HK2 mRNA, decreasing HK2 mRNA stability and inhibiting glucose metabolism reprogramming and LUAD cell invasion in vitro and in vivo. The finding that the MYO16-AS1/IGF2BP3-mediated glucose metabolism reprogramming mechanism regulates HK2 expression provides novel insight into the process of LUAD invasion and suggests that MYO16-AS1 may be a therapeutic target for LUAD.

Circ_16601 facilitates Hippo pathway signaling via the miR-5580-5p/FGB axis to promote my-CAF recruitment in the TME and LUAD progression.

BACKGROUND: Lung cancer represents a significant public health issue in China, given its high incidence and mortality rates. Circular RNAs (circRNAs) have been recently proposed to participate in the development and progression of tumors. Nevertheless, their particular roles in the pathogenesis of lung adenocarcinoma (LUAD), the tumor microenvironment (TME), and the underlying molecular mechanisms are still not well understood. METHODS: High-throughput sequencing was used to analyze the circRNAs expression profiles in 7 pairs of human LUAD tissues. shRNA was used to knockdown the YAP1 and FGB genes. RNA sequencing and RT-qPCR were performed to classify the regulatory effects of circ_16601 in LUAD cells. The progression effect of circ_16601 on lung cancer was investigated in vitro and in vivo. RESULTS: The circ_16601 is significantly elevated in LUAD tissues compared to adjacent normal lung tissues, and its high expression is positively associated with poor prognosis in LUAD patients. Additionally, circ_16601 overexpression promotes LUAD cell proliferation in vitro and increases xenograft tissue growth in mice in vivo; circ_16601 also could recruit fibroblasts to cancer associate fibroblasts. Mechanistically, circ_16601 can directly bind to miR-5580-5p, preventing its ability to degrade FGB mRNA and enhancing its stability. Subsequently, circ_16601 promotes the activation of the Hippo pathway in a YAP1-dependent manner, leading to LUAD progression. CONCLUSIONS: Our findings shed valuable insights into the regulatory role of circ_16601 in LUAD progression and highlight its potential as a diagnostic and therapeutic target in LUAD. Overall, this study provides theoretical support to improve the prognosis and quality of life of patients suffering from this devastating disease.

Circular RNA circ-FIRRE interacts with HNRNPC to promote esophageal squamous cell carcinoma progression by stabilizing GLI2 mRNA.

Increasing evidence has shown that circular RNAs (circRNAs) interact with RNA-binding proteins (RBPs) and promote cancer progression. However, the function and mechanism of the circRNA/RBP complex in esophageal squamous cell carcinoma (ESCC) are still largely unknown. Herein, we first characterized a novel oncogenic circRNA, circ-FIRRE, by RNA sequencing (Ribo-free) profiling of ESCC samples. Furthermore, we observed marked circ-FIRRE overexpression in ESCC patients with high TNM stage and poor overall survival. Mechanistic studies indicated that circ-FIRRE, as a platform, interacts with the heterogeneous nuclear ribonucleoprotein C (HNRNPC) protein to stabilize GLI2 mRNA by directly binding to its 3'-UTR in the cytoplasm, thereby resulting in elevated GLI2 protein expression and subsequent transcription of its target genes MYC, CCNE1, and CCNE2, ultimately contributing to ESCC progression. Moreover, HNRNPC overexpression in circ-FIRRE knockdown cells notably abolished circ-FIRRE knockdown-mediated Hedgehog pathway inhibition and ESCC progression impairment in vitro and in vivo. Clinical specimen results showed that circ-FIRRE and HNRNPC expression was positively correlated with GLI2 expression, which reveals the clear significance of the circ-FIRRE/HNRNPC-GLI2 axis in ESCC. In summary, our results indicate that circ-FIRRE could serve as a valuable biomarker and potential therapeutic target for ESCC and highlight a novel mechanism of the circ-FIRRE/HNRNPC complex in ESCC progression regulation.

CircABCA13 acts as a miR-4429 sponge to facilitate esophageal squamous cell carcinoma development by stabilizing SRXN1.

Circular RNAs (circRNAs) play a pivotal role in the tumorigenesis and progression of various cancers. However, the role and mechanisms of circABCA13 in esophageal squamous cell carcinoma (ESCC) are largely unknown. Here, we reported that circABCA13, a novel circular RNA generated by back-splicing of the intron of the ABCA13 gene, is highly expressed in ESCC tumor tissues and cell lines. Upregulation of circABCA13 correlated with TNM stage and a poor prognosis in ESCC patients. While knockdown of circABCA13 in ESCC cells significantly reduced cell proliferation, migration, invasion, and anchorage-independent growth, overexpression of circABCA13 facilitated tumor growth both in vitro and in vivo. In addition, circABCA13 directly binds to miR-4429 and sequesters miR-4429 from its endogenous target, SRXN1 mRNA, which subsequently upregulates SRXN1 and promotes ESCC progression. Consistently, overexpression of miR-4429 or knockdown of SRXN1 abolished malignant behavior promotion of ESCC results from circABCA13 overexpression in vitro and in vivo. Collectively, our study uncovered the oncogenic role of circABCA13 and its mechanism in ESCC, suggesting that circABCA13 could be a potential therapeutic target and a predictive biomarker for ESCC patients.

Identification of a transcription factor­cyclin family genes network in lung adenocarcinoma through bioinformatics analysis and validation through RT­qPCR.

Lung adenocarcinoma (LUAD) is the predominant pathological subtype of lung cancer, which is the most prevalent and lethal malignancy worldwide. Cyclins have been reported to regulate the physiology of various types of tumors by controlling cell cycle progression. However, the key roles and regulatory networks associated with the majority of the cyclin family members in LUAD remain unclear. In total, 556 differentially expressed genes were screened from the GSE33532, GSE40791 and GSE19188 mRNA microarray datasets by R software. Subsequently, protein-protein interaction network containing 499 nodes and 4,311 edges, in addition to a significant module containing 76 nodes and 2,631 edges, were extracted through the MCODE plug-in of Cytoscape. A total of four cyclin family genes [cyclin (CCNA2, CCNB1, CCNB2 and CCNE2] were then found in this module. Further co-expression analysis and associated gene prediction revealed forkhead box M1 (FOXM1), the common transcription factor of CCNB2, CCNB1 and CCNA2. In addition, using GEPIA database, it was found that the high expression of these four genes were simultaneously associated with poorer prognosis in patients with LUAD. Experimentally, it was proved that these four hub genes were highly expressed in LUAD cell lines (Beas-2B and H1299) and LUAD tissues through qPCR, western blot analysis and immunohistochemical studies. The diagnostic value of these 4 hub genes in LUAD was analyzed by logistic regression, CCNA2 was deleted, following which a nomogram diagnostic model was constructed accordingly. The area under the curve values of CCNB1, CCNB2 and FOXM1 diagnostic models were calculated to be 0.92, 0.91 and 0.96 in the training set (Combined dataset of GSE33532, GSE40791 and GSE19188) and two validation sets (GSE10072 and GSE75037), respectively. To conclude, data from the present study suggested that the FOXM1/cyclin (CCNA2, CCNB1 and/or CCNB2) axis may serve a regulatory role in the development and prognosis of LUAD. Specifically, CCNB1, CCNB2 and FOXM1 have potential as diagnostic markers and/or therapeutic targets for LUAD treatment.

Exosomal miR-10527-5p Inhibits Migration, Invasion, Lymphangiogenesis and Lymphatic Metastasis by Affecting Wnt/ß-Catenin Signaling via Rab10 in Esophageal Squamous Cell Carcinoma.

Background: Cancer cell-derived exosomal microRNAs (miRNAs) play critical role in orchestrating intercellular communication between tumor cells and tumor microenvironmental factors, including lymphatic endothelial cells (LECs). Nevertheless, the functions and underlying mechanisms of exosomal miRNAs in lymphatic metastasis and lymphangiogenesis in esophageal squamous cell carcinoma (ESCC) remain unclear. Methods: Small RNA sequencing, Gene Expression Omnibus (GEO) analysis and qRT‒PCR were performed to identify the candidate exosomal miRNAs involved in ESCC metastasis. Receiver operating characteristic curve analysis was conducted to evaluate the diagnostic potential of exosomal miR-10527-5p in predicting lymph node metastasis (LNM) status. An in vitro coculture system was used to investigate the effects of exosomal miR-10527-5p on ESCC cells and human LECs (HLECs), followed by a popliteal LNM assay in vivo. The relationship between miR-10527-5p and Rab10 was identified by dual-luciferase reporter, fluorescence in situ hybridization and qRT‒PCR assays. Then, a series of rescue assays were performed to further investigate whether Rab10 is involved in exosomal miR-10527-5p mediated ESCC metastasis. Results: MiR-10527-5p was found to be notably reduced in both the plasma exosomes and tumor tissues of ESCC patients with LNM, and plasma exosomal miR-10527-5p had a high sensitivity and specificity for discrimination of LNM status. Moreover, exosome-shuttled miR-10527-5p suppressed the migration, invasion and epithelial-to-mesenchymal transition (EMT) of ESCC cells as well as the migration and tube formation of HLECs via Wnt/ß-catenin signaling in vitro and in vivo. Further investigation revealed that Rab10 was a direct target of miR-10527-5p, and re-expression of Rab10 neutralized the inhibitory effects of exosomal miR-10527-5p. Conclusion: Our study demonstrated that exosomal miR-10527-5p had a strong capability to predict preoperative LNM status and anti-lymphangiogenic effect. Exosomal miR-10527-5p inhibited lymphangiogenesis and lymphatic metastasis of ESCC in a vascular endothelial growth factor-C (VEGF-C)-independent manner, showing potential as a therapeutic target for ESCC patients.

Triptolide promotes degradation of the unfolded gain-of-function Tp53R175H/Y220C mutant protein by initiating heat shock protein 70 transcription in non-small cell lung cancer.

Background: The mutation rate of the tumor protein P53 (TP53) has been reported to be greater than 50% in non-small cell lung cancer (NSCLC), and gain-of-function (GOF) mutations in unfolded P53 (TP53R175H and TP53Y220C) have been associated with poor prognosis. However, the best treatment for patients with NSCLC harboring unfolded mutant P53 (mutp53) remains unclear. Triptolide is a natural compound derived from Tripterygium wilfordii that has shown a strong antitumor effect in a variety of cancers. Our study aimed to explore the GOF mutations in unfolded mutp53 (TP53R175H and TP53Y220C) and to clarify the molecular mechanisms by which triptolide regulates the degradation of unfolded mutp53 proteins in NSCLC. Methods: Two unfolded proteins harboring TP53R175H and TP53Y220C mutations were selected to explore their functions in NSCLC progression. NCI-H1299 cells (TP53-null) were transfected with wild-type TP53 (TP53WT), TP53R175H, or TP53Y220C genes and treated with triptolide or a vehicle. Wound healing and transwell assays were performed to measure cell migration and invasion in vitro. Lung metastasis models were constructed through tail vein injection of mutant cells into BALB/c nude mice to evaluate the effect of triptolide on metastasis in vivo. Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunoprecipitation, and dual-luciferase reporter assays were performed to explore the relevant molecular mechanisms. Results: Our study revealed that triptolide treatment reduced TP53R175H levels and that the TP53Y220C mutation enhanced the invasion and migration of NCI-H1299 cells. Mechanistically, triptolide promoted TP53R175H and TP53Y220C protein proteasomal degradation mediated through the E3 ligase murine double minute 2 (MDM2) by directly interacting with heat shock protein 70 (HSP70). Moreover, by upregulating HSP70 transcription, triptolide contributed to the protein degradation of the GOF mutp53. Conclusions: Our study reports, for the first time, the mechanism underlying triptolide-regulated protein degradation of TP53R175H or TP53Y220C, which offers new insight into developing a better therapeutic strategy for patients with NSCLC who express the unfolded mutp53 GOF protein.