Hsa_circ_0003258 promotes prostate cancer metastasis by complexing with IGF2BP3 and sponging miR-653-5p

Background More and more studies have shown that circular RNAs (circRNAs) play a critical regulatory role in many cancers. However, the potential molecular mechanism of circRNAs in prostate cancer (PCa) remains largely unknown. Methods Differentially expressed circRNAs were identified by RNA sequencing. The expression of hsa_circ_0003258 was evaluated using quantitative real-time PCR and RNA in situ hybridization. The impacts of hsa_circ_0003258 on the metastasis of PCa cells were investigated by a series of in vitro and in vivo assays. Lastly, the underlying mechanism of hsa_circ_0003258 was revealed by Western blot, biotin-labeled RNA pulldown, RNA immunoprecipitation, luciferase assays and rescue experiments. Results Increased expression of hsa_circ_0003258 was found in PCa tissues and was associated with advanced TNM stage and ISUP grade. Overexpression of hsa_circ_0003258 promoted PCa cell migration by inducing epithelial mesenchymal transformation (EMT) in vitro as well as tumor metastasis in vivo, while knockdown of hsa_circ_0003258 exerts the opposite effect. Mechanistically, hsa_circ_0003258 could elevate the expression of Rho GTPase activating protein 5 (ARHGAP5) via sponging miR-653-5p. In addition, hsa_circ_0003258 physically binds to insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) in the cytoplasm and enhanced HDAC4 mRNA stability, in which it activates ERK signalling pathway, then triggers EMT programming and finally accelerates the metastasis of PCa. Conclusions Upregulation of hsa_circ_0003258 drives tumor progression through both hsa_circ_0003258/miR-653-5p/ARHGAP5 axis and hsa_circ_0003258/IGF2BP3 /HDAC4 axis. Hsa_circ_0003258 may act as a promising biomarker for metastasis of PCa and an attractive target for PCa intervention.

Iron-Dependent Mitochondrial Dysfunction Contributes to the Pathogenesis of Pulmonary Fibrosis

Although the pathogenesis of pulmonary fibrosis remains unclear, it is known to involve epithelial injury and epithelial-mesenchymal transformation (EMT) as a consequence of cigarette smoke (CS) exposure. Moreover, smoking deposits iron in the mitochondria of alveolar epithelial cells. Iron overload in mitochondria causes the Fenton reaction, leading to reactive oxygen species (ROS) production, and ROS leakage from the mitochondria induces cell injury and inflammation in the lungs. Nevertheless, the mechanisms underlying iron metabolism and pulmonary fibrosis are yet to be elucidated. In this study, we aimed to determine whether iron metabolism and mitochondrial dysfunction are involved in the pathogenesis of pulmonary fibrosis. We demonstrated that administration of the iron chelator deferoxamine (DFO) reduced CS-induced pulmonary epithelial cell death, mitochondrial ROS production, and mitochondrial DNA release. Notably, CS-induced cell death was reduced by the administration of an inhibitor targeting ferroptosis, a unique iron-dependent form of non-apoptotic cell death. Transforming growth factor-β-induced EMT of pulmonary epithelial cells was also reduced by DFO. The preservation of mitochondrial function reduced Transforming growth factor-β-induced EMT. Furthermore, transbronchial iron chelation ameliorated bleomycin-induced pulmonary fibrosis and leukocyte migration in a murine model. Our findings indicate that iron metabolism and mitochondrial dysfunction are involved in the pathogenesis of pulmonary fibrosis. Thus, they may be leveraged as new therapeutic targets for pulmonary fibrosis.

EGFL6 Promotes Bone Metastasis of Lung Adenocarcinoma by Enhancing Osteoclast Differentiation and Stimulating Cancer Cell Metastasis

Background Lung cancer is still the most fatal cancer today with approximately 30%-40% of these patients will develop bone metastasis. Lung adenocarcinoma (LUAD) is the most common and aggressive type of lung cancer. The relationship between LUAD and bone metastasis and its underlying mechanism remains unclear. This study proved that epidermal growth factor-like domain multiple 6 (EGFL6) was highly expressed in LUAD specimens of patients, and the expression level was positively correlated with bone metastasis of LUAD. Method The expression of EGFL6 in cancer tissues was detected by IHC. CCK-8, colony formation assay, migration and invasion assay, wound healing assay, immunocytochemistry, RT-PCR, Western blotting, ELISA, bone resorption, TRAP staining and H&E staining were performed. A nude mouse model of LUAD-induced bone destruction was established by injecting A549 cells in different EGFL6 expression levels. Results EGFL6 is elevated in LUAD and is associated with bone metastasis. In vivo, implantation of human adenocarcinoma A549 cells with a higher expression of EGFL6 not only increased tumor growth rate but also bone resorption of tibias in nude mice. In vitro, the secretion of EGFL6 from A549 cells increased osteoclast differentiation but had little effect on osteogenic differentiation. To reveal the underlying mechanism, we demonstrated that EGFL6 enhanced osteoclast differentiation through activating nuclear factor-kappa B (NF-κB) and downstream c-Fos/NFATc1 signaling pathways, and in addition promoted the proliferation, migration and invasion of A549 cells through enhancing the epithelial mesenchymal transformation (EMT) and promoting Wnt/β-catenin and PI3K/AKT/mTOR signaling pathways. Conclusions We unveil EGFL6 as a predictor in bone metastasis of LUAD and underscore the relevance of EGFL6 as a therapeutic target.

Expression of transcription factor SALL4 in bladder urothelial carcinoma and its relationship with epithelial mesenchymal transformation

Purpose To evaluate the expression levels of spalt-like transcription factor 4 (SALL4) in bladder urothelial carcinoma, and determine its role and underlying mechanism of action in mediating the proliferation, migration and invasion of bladder cancer cells. Methods SALL4 expression was examined in 170 bladder patient urothelial carcinoma tissue samples by immunohistochemistry. Using a SALL4 overexpression plasmid and siRNA-SALL4, the effects of overexpressing and silencing SALL4 on the proliferation, migration and invasion of T24 and 5637 bladder cancer cells was examined using CCK8, migration and invasion assays. Western blot analysis was performed to detect epithelial mesenchymal transition (EMT)-related protein expression. Results The expression rate of SALL4 in low-grade and high-grade urothelial carcinomas was found to be 10% and 49.12%, respectively (P < 0.001), while SALL4 expression was not observed in the normal urothelium. SALL4 protein expression was positively correlated with histological grade, depth of invasion, lymphatic metastasis and vascular invasion of bladder urothelial carcinoma (P < 0.05). In addition, a shorter overall survival time and poor prognosis was observed in the SALL4 protein expression group. Overexpression of SALL4 led to significantly increased cell proliferation, migration and invasion, while knockdown of SALL4 had the opposite effect. In the SALL4 overexpression group, N-cadherin, vimentin, Snail and β-catenin expression were significantly increased, while E-cadherin expression was significantly decreased (P < 0.05). Promotion of EMT was also observed in SALL4-overexpressing cells. In contrast, in the SALL4-siRNA-treated group, EMT was reversed and β-catenin expression was reduced. Conclusions Our data show that the SALL4 gene is associated with the proliferation, invasion and poor prognosis of bladder urothelial carcinoma, and may mediate its effects via the Wnt/β-catenin signaling pathway, which regulates the EMT pathway. Thus, down-regulation of SALL4 may provide a novel therapeutic strategy for the treatment of bladder urothelial carcinoma.

Adipocytokines and disease progression in endometrial cancer: a systematic review

The objective of the study was to document the effect of adipocytokines on endometrial cancer progression. A search of the databases CINAHL, Medline, PubMed, Cochrane, Web of Science, Embase and Google Scholar was performed for English language articles from January 2000 to December 2020 using the keywords: (Endometrial cancer) AND (progression OR metastasis) AND (adipocytokine OR adiponectin OR leptin OR visfatin OR IL-6 OR TNF-α OR adipokine OR cytokine). Forty-nine studies on adipocytokines have been included in this review. Adiponectin has been linked with anti-proliferative and anti-metastatic effects on endometrial cancer cells and is associated with a better prognosis. Leptin, visfatin and resistin are linked to the stimulation of endometrial cancer growth, proliferation, invasion and metastasis and are associated with worse prognosis or with a higher grade/stage of endometrial cancer. IL-6, Il-11, IL-31, IL-33, TNF-α, TGF-β1, SDF-1 and CXCR are involved in endometrial cancer cell growth and metastasis or involved in epithelial mesenchymal transformation (EMT) or associated with advanced disease. Adipocytokines have been found to directly impact endometrial cancer cell proliferation, invasion and migration. These molecules and their signalling pathways may be used to determine prognosis and course of the disease and may also be exploited as potential targets for cancer treatment and prevention of progression.

TGFβ: Signaling Blockade for Cancer Immunotherapy

Discovered over four decades ago, transforming growth factor β (TGFβ) is a potent pleiotropic cytokine that has context-dependent effects on most cell types. It acts as a tumor suppressor in some cancers and/or supports tumor progression and metastasis through its effects on the tumor stroma and immune microenvironment. In TGFβ-responsive tumors it can promote invasion and metastasis through epithelial-mesenchymal transformation, the appearance of cancer stem cell features, and resistance to many drug classes, including checkpoint blockade immunotherapies. Here we consider the biological activities of TGFβ action on different cells of relevance toward improving immunotherapy outcomes for patients, with a focus on the adaptive immune system. We discuss recent advances in the development of drugs that target the TGFβ signaling pathway in a tumor-specific or cell type–specific manner to improve the therapeutic window between response rates and adverse effects. Expected final online publication date for the Annual Review of Cancer Biology, Volume 6 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

METTL3 Depletion Contributes to HR+/HER2- Breast Cancer Progression and Drug Resistance via m6A Modification of Constituents of the CDKN1A/EMT and BAX/caspase-9/-3/-8 Signalling Pathways

Background: Chemotherapy is an important strategy for the treatment of hormone receptor positive / human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer (BC), but this subtype has a low response to chemotherapy. Growing evidence indicates that N6-methyladenosine (m6A) is the most common RNA modification in eukaryotic cells and that methyltransferase-like 3 (METTL3) participates in tumour progression in several cancer types. Therefore, exploring the function of METTL3 in HR+HER2- BC initiation and development is still significant.Methods: mRNA and protein expression levels were analysed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. Cell proliferation was detected by CCK-8 assays, cell migration was analysed by wound healing assays, and apoptosis was analysed by TUNEL assays. Finally, m6A modification was analysed by methylated RNA immunoprecipitation (MeRIP).Results: Chemotherapy-induced downregulation of the m6A modification is regulated by METTL3 in HR+/HER2- BC. METTL3 knockdown in MCF-7/T47D cells weakened the drug sensitivity of HR+/HER2- BC cells by promoting tumour proliferation and metastasis and inhibiting apoptosis. Mechanistically, CDKN1A was subsequently recognized as a downstream target of METTL3 that activates the AKT pathway and promotes epithelial-mesenchymal transformation (EMT). Moreover, the RNA level of BAX was decreased due to a lower level of m6A modification mediated by METTL3, and apoptosis was inhibited by inactivation of caspase 3/9/8.Conclusion: METTL3 regulates the proliferation, migration, and drug sensitivity of HR+/HER2- BC via activation of the CDKN1A/EMT and m6A-BAX/caspase 9/3/8 signalling pathways, which suggests its role as a potential biomarker for predicting the prognosis of patients with HR+/HER2- BC.

Vardenafil Activity in Lung Fibrosis and In Vitro Synergy with Nintedanib

Idiopathic pulmonary fibrosis (IPF) remains an intractably fatal disorder, despite the recent advent of anti-fibrotic medication. Successful treatment of IPF, like many chronic diseases, may benefit from the concurrent use of multiple agents that exhibit synergistic benefit. In this light, phosphodiesterase type 5 inhibitors (PDE5-Is), have been studied in IPF primarily for their established pulmonary vascular effects. However, recent data suggest certain PDE5-Is, particularly vardenafil, may also reduce transforming growth factor beta 1 (TGF-β1) activation and extracellular matrix (ECM) accumulation, making them a potential target for therapy for IPF. We evaluated fibroblast TGF-β1-driven extracellular matrix (ECM) generation and signaling as well as epithelial mesenchymal transformation (EMT) with pretreatment using the PDE5-I vardenafil. In addition, combinations of vardenafil and nintedanib were evaluated for synergistic suppression of EMC using a fibronectin enzyme-linked immunosorbent assay (ELISA). Finally, the effects of vardenafil on fibrosis were investigated in a bleomycin mouse model. Our findings demonstrate that vardenafil suppresses ECM generation alone and also exhibits significant synergistic suppression of ECM in combination with nintedanib in vitro. Interestingly, vardenafil was shown to improve fibrosis markers and increase survival in bleomycin-treated mice. Vardenafil may represent a potential treatment for IPF alone or in combination with nintedanib. However, additional studies will be required.

Identification and Validation of PLOD2 as an Adverse Prognostic Biomarker for Oral Squamous Cell Carcinoma

Background: Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a key enzyme that catalyzes the hydroxylation of lysine, plays a crucial role in the progression of several solid tumors. However, its spatial expression profile and prognostic significance in oral squamous cell carcinoma (OSCC) have not been revealed. Materials: Mass spectrometry was used to explore amino acid perturbations between OSCC tumor tissues and paired normal tissues of 28 patients. Then, PLOD2 mRNA and protein levels were assessed using several public databases and 18 pairs of OSCC patients’ tissues. Additionally, PLOD2 spatial expression profiles were investigated in 100 OSCC patients by immunohistochemistry and its diagnostic and prognostic values were also evaluated. Lastly, gene set enrichment analysis (GSEA) was used to investigate the potential functions of PLOD2 in OSCC. Results: Lysine was significantly elevated in OSCC tissues and could effectively distinguish tumor from normal tissues (AUC = 0.859, p = 0.0035). PLOD2 mRNA and protein levels were highly increased in tumor tissues of head and neck squamous cell carcinoma (HNSCC) (p < 0.001) and OSCC compared with those in nontumor tissues (p < 0.001). Histopathologically, PLOD2 was ubiquitously expressed in tumor cells (TCs) and fibroblast-like cells (FLCs) of OSCC patients but absent in tumor-infiltrating lymphocytes (TILs). Patients with highly expressed PLOD2 in TCs (PLOD2TCs) and FLCs (PLOD2FLCs) showed poor differentiation, a worse pattern of invasion (WPOI) and more lymph node metastasis (LNM), contributing to higher postoperative metastasis risk and poor survival time. However, PLOD2FLCs rather than PLOD2TCs was an independent risk factor for survival outcomes in OSCC patients. Molecularly, GSEA demonstrated highly expressed PLOD2 was mainly enriched in epithelial–mesenchymal transformation (EMT), TGF-beta signaling and hypoxia pathway, which are associated with poor clinical outcomes of OSCC patients. Conclusions: PLOD2 was a poor prognostic biomarker for OSCC patients and may affect the metastasis of OSCC through EMT pathway. These findings might shed novel sights for future research in PLOD2 targeted OSCC therapy.

Cytoplasmic eIF6 promotes OSCC malignant behavior through AKT pathway

Background Eukaryotic translation initiation factor 6 (eIF6), also known as integrin β4 binding protein, is involved in ribosome formation and mRNA translation, acting as an anti-association factor. It is also essential for the growth and reproduction of cells, including tumor cells. Yet, its role in oral squamous cell carcinoma (OSCC) remains unclear. Methods The expression characteristics of eIF6 in 233 samples were comprehensively analyzed by immunohistochemical staining (IHC). Effects of eIF6 over-expression and knockdown on cell proliferation, migration and invasion were determined by CCK-8, wound healing and Transwell assays. Western blot, immunofluorescence (IF) and co-immunoprecipitation (co-IP) were performed for mechanical verification. Results We found that cytoplasmic eIF6 was abnormally highly expressed in OSCC tissues, and its expression was associated with tumor size and the clinical grade. Amplification of eIF6 promoted the growth, migration and invasion capabilities of OSCC cell lines in vitro and tumor growth in vivo. Through Western blot analysis, we further discovered that eIF6 significantly promotes epithelial-mesenchymal transformation (EMT) in OSCC cells, while depletion of eIF6 can reverse this process. Mechanistically, eIF6 promoted tumor progression by activating the AKT signaling pathway. By performing co-immunoprecipitation, we discovered a direct interaction between endogenous eIF6 and AKT protein in the cytoplasm. Conclusion These results demonstrated that eIF6 could be a new therapeutic target in OSCC, thus providing a new basis for the prognosis of OSCC patients in the future.