Exosome-transported circ_0001955 as a potent driver of breast cancer by regulating the miR-708-5p/PGK1 axis.

Increasing evidence shows that exosome-mediated delivery of circular RNA (circRNA) is implicated in breast cancer progression. This study aimed to elucidate the role of exosome-transported circ_0001955 in breast cancer. The expression of circ_0001955, miR-708-5p, and phosphoglycerate kinase 1 (PGK1) messenger RNA (mRNA) was detected by quantitative real-time polymerase chain reaction (qRT-PCR); the protein levels of PGK1 and hexokinase 2 (HK2) were detected by western blot (WB). 5'-Ethynyl-2'-deoxyuridine (EdU) and colony formation assay were used to determine cell proliferation. Glycolytic metabolism was analyzed by corresponding kits to detect the associated indicators. The role of circ_0001955 in vivo was studied by establishing animal models. The potential binding relationship between miR-708-5p and circ_0001955 or PGK1 was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Circ_0001955 was highly expressed in breast cancer tissues and cell lines, as well as in exosomes from breast cancer cell lines. The deficiency of circ_0001955 blocked proliferation, decreased the IC50 value of paclitaxel (PTX), and blocked glycolysis in MCF-7 and MDA-MB-231 cells. Circ_0001955 knockdown also inhibited tumor growth in vivo. Circ_0001955 directly combined with miR-708-5p, and the miR-708-5p inhibitor reversed the effects of sh-circ_0001955. PGK1 was a target of miR-708-5p, and circ_0001955 indirectly promoted PGK1 expression by binding to miR-708-5p. PGK1 overexpression abolished the function of miR-708-5p in breast cancer. Exosomal circ_0001955 excreted from breast cancer cells facilitated proliferation and glycolysis and enhanced the IC50 value of PTX in breast cancer cells by sponging miR-708-5p to upregulate PGK1.

Li W ，Jin G ，Zhou H ，Gao Y ，Ge Y ，Zhang H ... -  《-》

Circular RNA (circ)_0053277 Contributes to Colorectal Cancer Cell Growth, Angiogenesis, Metastasis and Glycolysis.

Circular RNAs (circRNAs) have been found to be abnormally expressed in many cancers, including colorectal cancer (CRC). Circ_0053277 has been found to mediate CRC malignant processes and may be a key regulator for CRC progression. Therefore, its role and potential molecular mechanism in CRC process deserve further investigation. Quantitative real-time PCR was used to detect the expression levels of circ_0053277, microRNA-520 h (miR-520 h) and hexokinase 1 (HK1). Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, wound healing assay, transwell assay, and tube formation assay were used to detect CRC cell proliferation, apoptosis, migration, invasion, and angiogenesis. The protein levels of apoptosis-related markers and HK1 were detected by western blot. The relationship between circ_0053277 and miR-520 h or miR-520 h and HK1 in CRC cells was verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Cell glycolysis was assessed by detecting glucose uptake and lactate production. The effect of silenced circ_0053277 on CRC tumor growth was evaluated by xenograft model in vivo. Our study found that circ_0053277 expression was elevated in CRC tissues and cells. Moreover, circ_0053277 knockdown suppressed CRC cell proliferation, angiogenesis, migration and invasion, while promoting apoptosis. In terms of mechanism, circ_0053277 sponged miR-520 h, and HK1 was the target of miR-520 h. Meanwhile, miR-520 h inhibitor reversed the inhibitory effect of circ_0053277 silencing on CRC cell progression, and HK1 overexpression also overturned the suppressive effect of miR-520 h on CRC cell growth, angiogenesis and metastasis. Moreover, circ_0053277 knockdown inhibited the glycolysis of CRC cells by regulating miR-520 h/HK1 pathway. In addition, knockdown of circ_0053277 reduced CRC tumor growth in vivo. Circ_0053277 promoted CRC cell growth, angiogenesis, metastasis and glycolysis by miR-520 h/HK1 pathway, confirming that circ_0053277 might be a potential clinical target for CRC treatment.

Zhuang J ，Song W ，Li M ，Kang D ，Cheng K ... -  《-》

EGCG targeting STAT3 transcriptionally represses PLXNC1 to inhibit M2 polarization mediated by gastric cancer cell-derived exosomal miR-92b-5p.

M2-polarized tumor-associated macrophages (TAMs) predominate in tumor microenvironment (TME) and serve primary functions in tumor progression, including growth, angiogenesis, metastasis, immunosuppression, chemoresistance, and poor prognosis. The reversal of M2 polarization provides a new treatment strategy for cancer. Presently, the molecular mechanisms of M2 polarization have yet to be fully characterized, and there is a lack of effective therapeutic targets and drugs. Cancer cells initiate an immunosuppressive TME by recruiting macrophages and promoting M2 polarization through the secretion of inflammatory factors. Accordingly, blocking cancer cell-induced TAM M2 polarization may present a more effective strategy from the perspective of cancer cells. Hedyotis diffusa Willd (HDW) possesses immunomodulatory and antitumor properties, and is a precious and direct source of small molecule natural products with a dual function of inhibition of tumor growth and tumor cell-mediated M2 polarization. To identify a new target promoting gastric cancer (GC) cell growth and GC cell-mediated M2 polarization from mRNA profiles of GC cells treated with HDW injection (HDI) and to excavate a natural product from HDI that can regulate related mRNA and inhibit the aforementioned effects. RNA sequencing (RNA-seq) was used to analyze HDI-regulated differentially expressed mRNAs (HRmRNAs) in MKN45 cells. Weighted gene co-expression network analysis (WGCNA), univariate and multivariate Cox regression analysis, KM survival curves, and association analysis between HRmRNA and clinical characteristics/tumor infiltrating immune cells (TIICs) individually were utilized to screen out the target HRmRNA associated with prognosis and M2 macrophage infiltration in GC. shRNA lentiviral vectors were used for stably silencing, and transient overexpressing plasmids were constructed for overexpression. CCK8, EdU, colony formation, migration and invasion assays were used to validate the function of drugs and molecules in GC. HDI constituent analysis was performed using UHPLC-QE-MS. A network of HDI constituent-hub transcription factor (TF)-HRmRNA was constructed based on RNA-Seq, network pharmacology and TFs prediction. Exosome isolation and identification were performed using ultracentrifugation, NTA, TEM and western blot. Apoptosis and macrophage phenotypes were determined by flow cytometric analysis. Small RNA-Seq made exosomal miRNA identification. Small molecule interaction with targets were analyzed using molecular docking, SPR and CETSA. The direct relationship between transcription factors and promoters was verified using ChIP-QPCR and dual-luciferase reporter gene assay. A nude mice xenograft tumor model was established for vivo validation. HDI inhibited MKN45 cell proliferation, migration, invasion and promoted apoptosis. RNA-Seq identified 2583 HRmRNAs. PLXNC1 was screened out as the target HRmRNA associated with prognosis and M2 macrophage infiltration in GC. PLXNC1 promoted GC cell proliferation and facilitated TAMs M2 polarization by transferring GC cell-derived exosomal miR-92b-5p, inhibiting SOCS7-STAT3 interactions and subsequently activating STAT3 in macrophages. M2 TAMs induced by PLXNC1-mediated GC cell-derived exosomes promoted GC cell migration and invasion. PLXNC1 regulated exosomal miR-92b-5p through the MEK1/MSK1/CREB1 pathway. STAT3 could transcriptionally regulate PLXNC1 expression in GC cells. The network of HDI constituent-hub TF-HRmRNA showed epigallocatechin gallate (EGCG) from HDI targeted STAT3 to transcriptionally regulate PLXNC1 expression. EGCG as a natural product directly bound to STAT3 to diminish its nuclear localization, resulting in the transcriptional repression of PLXNC1 and the reversal of M2 polarization induced by PLXNC1-mediated GC cell-derived exosomes. PLXNC1 is a novel target exerting dual effects on GC cell proliferation and GC cell-mediated M2 polarization. EGCG derived from HDI inhibits GC cell proliferation and targets STAT3 to inhibit M2 polarization induced by PLXNC1-mediated exosomes derived from GC cells, which may be a multi-target therapeutic agent for GC cell proliferation and immune microenvironment.

Yi J ，Ye Z ，Xu H ，Zhang H ，Cao H ，Li X ，Wang T ，Dong C ，Du Y ，Dong S ，Zhou W ... -  《-》

Exosome-delivered circRNA circSYT15 contributes to cisplatin resistance in cervical cancer cells through the miR-503-5p/RSF1 axis.

Chen Z ，Xu Z ，Wang Q ，Wang L ，Zhang H ，Wang W ，Zhao H ，Guo Y ，Cui J ... -  《-》

Circular RNA circ_0004630 promotes malignancy and glycolysis of nonsmall cell lung cancer by sponging microRNA-1208 and regulating leucine-rich repeat kinase 2 expression.

Emerging evidence has discovered that circular RNAs play important regulators of nonsmall cell lung cancer (NSCLC), but the role and potential molecular mechanism of hsa_circ_100549 (circ_0004630) involved in NSCLC is poorly defined. In this study, circ_0004630, microRNA-1208 (miR-1208), and leucine-rich repeat kinase 2 (LRRK2) expression were detected using real-time quantitative polymerase chain reaction. Cell proliferation, colony formation, apoptosis, and invasion were assessed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine, colony formation, flow cytometry, and transwell assays. Protein levels of glucose transporter 1, Hexokinase 2, and LRRK2 were detected using western blot assay. Glucose consumption, lactate production, and adenosine triphosphate content were assessed using the corresponding kits. After predicting via bioinformatics software Circinteractome and Targetscan, the binding between miR-1208 and circ_0004630 or LRRK2 was verified by a dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assay. The xenograft tumor model analyzed the biological role circ_000460 on tumor growth in vivo. It was found that circ_0004630 and LRRK2 were increased, and miR-1208 was low expression in NSCLC tissues and cells. Functionally, the downregulation of circ_0004630 inhibited NSCLC cell proliferation, invasion, glycolysis, and accelerated apoptosis in vitro. In mechanism, circ_0004630 might work as a sponge of miR-1208 to modulate LRRK2 expression. In addition, DUXAP8 deficiency cured neuroblastoma tumor growth in vivo. In conclusion, circ_0004630 knockdown might suppress NSCLC cell proliferation, metastasis, and glycolysis partly by the miR-1208/LRRK2 axis. Our findings hinted at an important theoretical basis for further elucidating the pathogenesis of NSCLC and targeted therapy.

Zhang X ，Wu J ，Miao Y ，Wang J ，Wang E ... -  《-》