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To investigate the role and molecular mechanism of exosomal miR-224-5p in colorectal cancer (CRC). The miR-224-5p expression in CRC patient tissues and cell-derived exosomes was measured by laser capture microdissection and qRT-PCR, respectively. Dual-luciferase reporter gene assay was used to determine the target gene of miR-224-5p. The protein expressions of p53 and unc-51 like kinase 2 (ULK2) in CRC cells were detected by western blot. Flow cytometry was used to detect cell cycle and apoptosis. Cell proliferation was measured by CCK8 and EdU assay. The miR-224-5p expression was upregulated in CRC tissues and increased progressively with the rise of CRC stage. CRC cells secreted extracellular miR-224-5p mainly in an exosome-dependent manner, and then miR-224-5p could be transferred to surrounding tumor cells to regulate cell proliferation in the form of autocrine or paracrine. Moreover, ULK2 was characterized as a direct target of miR-224-5p and was downregulated in CRC tissues. Interestingly, ULK2 inhibited CRC cell proliferation in a p53-dependent manner. Furthermore, exosome-derived miR-224-5p partially reversed the proliferation regulation of ULK2 on CRC cells. Our findings demonstrate that exosome-transmitted miR-224-5p promotes p53-dependent cell proliferation by targeting ULK2 in CRC, which may offer promising targets for CRC prevention and therapy. [ABSTRACT FROM AUTHOR]

miR-224–5p has been shown to play both an oncogene and tumour suppressor role in many human tumours. However, the role and molecular mechanism of miR-224–5p in cutaneous melanoma remains unclear. miR-224–5p levels were downregulated in melanoma tissue, and low miR-224–5p expression was an independent risk factor for melanoma patients. miR-224–5p blocked proliferation, epithelial-to-mesenchymal transition (EMT), invasion, migration in BRAF wild-type melanoma cell, and overcome acquired BRAFi resistance in VMF-resistant melanoma cells. miR-224–5p exerted its role by directly repressing PAK4 to block the downstream CRAF/MEK/ERK pathways. We demonstrated that miR-224–5p inhibited melanoma growth and metastasis in vivo though xenograft tumor and pulmonary metastasis assay. Thus, miR-224–5p/PAK4-mediated CRAF/MEK/ERK pathways have therapeutic potential in melanoma treatment. [ABSTRACT FROM AUTHOR]

A growing body of evidence has indicated that long non-coding RNAs (lncRNAs) function as competing endogenous RNAs (ceRNAs) during tumorigenesis. In this study, the qRT-PCR results revealed that the lncRNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) was over-expressed in oral squamous cell carcinoma (OSCC) and decreased the survival rate of OSCC patients. Ectopic expression of FTH1P3 facilitates cell proliferation and colony formation in OSCC cells. Moreover, FTH1P3 acted as a competitive endogenous RNA (ceRNA), effectively becoming sponge for miR-224-5p and thereby modulating the expression of fizzled 5. Importantly, expression analysis revealed that both FTH1P3 and fizzled 5 were up-regulated in OSCC cell lines and tissues, and over-expression of fizzled 5 also functioned as an oncogene in OSCC cells. Our data demonstrated FTH1P3 facilitated OSCC progression by acting as a molecular sponge of miR-224-5p to modulate fizzled 5 expression. Thus, targeting the ceRNA network referring FTH1P3 may be a therapeutic target for treatment of OSCC. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) have been confirmed to be involved in the regulation of esophageal squamous cell carcinoma (ESCC) progression. According to GEO datasets (GSE112496 and GSE150476), we identified that circ_0007624 was abnormally down-regulated in ESCC. However, there is still no reports regarding the function and mechanism of circ_0007624 in ESCC development. Here, we found that circ_0007624 was significantly underexpressed in ESCC tissues, and low expression of circ_0007624 was indicative of a poor prognosis. Overexpressing circ_0007624 or silencing miR-224-5p suppressed cell proliferation, metastasis, epithelial-mesenchymal transition (EMT), and promoted apoptosis in vitro. Also, circ_0007624 up-regulation slowed ESCC tumor growth in vivo. Mechanistically, circ_0007624 could serve as a competing endogenous RNA (ceRNA) by sponging miR-224-5p to antagonize its inhibitory effect on the target cytoplasmic polyadenylation element binding protein 3 (CPEB3). Rescue experiments showed that the anti-cancer properity role of circ_0007624 in ESCC is partly reversed by the restoration of miR-224-5p or down-regulation of CPEB3. Furthermore, EGFR/PI3K/AKT pathway was involved in the regulation of circ_0007624/miR-224-5p/CPEB3 axis in ESCC. Together, our findings demonstrate for the first time that circ_0007624/miR-224-5p/CPEB3 suppresses ESCC progression by inactivating EGFR/PI3K/AKT signaling, providing a basis for developing circ_0007624-targeted therapies for ESCC patients. • Circ_0007624 expression is down-regulated in ESCC. • Circ_0007624 inhibits ESCC cell proliferation, migration, and invasion and induces apoptosis in vitro. • Circ_0007624 inactivates EGFR/PI3K/AKT signaling by targeting miR-224-5p/CPEB3 in ESCC • Circ_0007624 suppresses ESCC cell malignant phenotypes by regulating miR-224-5p/CPEB3 axis. [ABSTRACT FROM AUTHOR]

• Upregulation USP3 or inhibitor miR-224-5p restored GC cells proliferation and migration. • Upregulation of USP3 restored GC cells proliferation and migration. • Hsa_circ_0017639 expression promotes gastric cancer proliferation and metastasis. Gastric cancer (GC) is a common malignant tumor having poor prognosis globally. Circular RNA (circRNA) is a circular endogenous RNA generated by special selective splicing that occurs in various traits. Studies show that hsa_circ_0017639 is abnormally expressed and involved in tumorigenesis. Nevertheless, the hsa_circ_0017639 role in GC is unknown. This study detected hsa_circ_0017639 expression in a GC cell line using RT-qPCR. Subcellular localization of hsa_circ_0017639 was verified via FISH. We assessed correlations amongst miRNA, hsa_circ_0017639 and relative protein levels using luciferase reporter assays and RNA pulldown assays. The data illustrated that in hsa_circ_assays, expression was enhanced in GC cell. Downregulation of hsa_circ_0017639 decreased GC cell proliferation and migration in in vitro and in vivo experiments. RNA pulldown and RT-qPCR analysis verified that hsa_circ_0017639 sponged miR-224-5p. Bioinformatic and luciferase reporter assays validated that miR-224-5p and USP3 were downstream targets of hsa_circ_0017639. Upregulation of USP3 or downregulation of miR-224-5p restored proliferation and migration by MKN-28 and MGC-803 cells after hsa_circ_0017639 silencing. Upregulation of USP3 restored MKN-28 and MGC-803 cell proliferation and migration after overexpression of miR-224-5p. Our collective findings advised that hsa_circ_0017639 takes part in GC progression through regulating the miR-224-5p/USP3 axis, highlighting its potential as an effective GC therapeutic target. [ABSTRACT FROM AUTHOR]