Inhibition of KHSRP sensitizes colorectal cancer to 5-fluoruracil through miR-501-5p-mediated ERRFI1 mRNA degradation

K-homology (KH)-type splicing regulatory protein (KHSRP) is an RNA binding protein that participates in RNA variable splicing and stability, and facilitates the biogenesis of miRNAs that target mRNA. However, to date, the role of KHSRP in colorectal cancer (CRC) progression has not been reported. In this study, the function of KHSRP in CRC proliferation and 5-fluoruracil (5-FU) resistance was investigated. The upregulation of KHSRP expression was confirmed in CRC patient tissues and two CRC cell lines. Manipulating KHSRP expression altered cell proliferation and 5-FU resistance in CRC cells. ERRFI1, a downstream effector of KHSRP in CRC cells, reduced CRC cell proliferation. Sensitivity to 5-FU mediated by KHSRP knockdown was reversed by ERRFI1 knockdown. We found that KHSRP decreased ERRFI1 mRNA expression indirectly. By screening KHSRP-regulated miRNAs, we further found that miR-501-5p directly combines with KHSRP in CRC cells. Mechanistically, the results of a luciferase assay suggested that miR-501-5p directly binds to the ERRFI1 3′-untranslated region. Taken together, our data indicated that modification of ERRFI1 by KHSRP occurs through miR-501-5p, an essential mechanism driving CRC proliferation and 5-FU resistance. Insight into this mechanism may provide novel targets for overcoming drug resistance in CRC.     

LncRNA-UCA1 modulates progression of colon cancer through regulating the miR-28-5p/HOXB3 axis

Emerging evidence has shown that the long noncoding RNA urothelial carcinoma–associated 1 (UCA1) plays a tumor-promoting role in colorectal cancer, while miR-28-5p shows tumor-inhibitory activity in several tumor types. However, the mechanisms both of these in colon cancer progression are still unknown. In this work, the detailed roles and mechanisms of UCA1 and its target genes in colon cancer were studied. The results showed that UCA1 was upregulated in colon cancer tissues when compared with the adjacent nonhumorous tissues, as well as in the various colon cancer cell lines, but the expression of miR-28-5p showed an opposite trend. Furthermore, a high UCA1 level in colon cancer tissues is positively associated with the tumor size and advanced tumor stages. Functional assays revealed that both UCA1 knockdown and miR-28-5p overexpression could inhibit colon cancer cell growth and migration. Further mechanistic studies indicated that UCA1 knockdown played tumor suppressive roles in SW480 and HT116 cells through binding with miR-28-5p. We also, for the first time, identified HOXB3 as the target gene of miR-28-5p and that HOXB3 overexpression could mediate the functions of UCA1 in cell proliferation and migration of colon cancer cells. In conclusion, our data provided evidence for the regulatory network of UCA1/miR-28-5p/HOXB3 in colon cancer, suggesting that UCA1, miR-28-5p, and HOXB3 are the potential targets for colon cancer therapy.     

Long noncoding RNA FOXD3-AS1 promotes colon adenocarcinoma progression and functions as a competing endogenous RNA to regulate SIRT1 by sponging miR-135a-5p

More and more documents have proved that the abnormal expression of long noncoding RNAs (lncRNAs) are correlated with the initiation and progression of colorectal cancer (CRC). lncRNA FOXD3-AS1 has been reported in glioma for its oncogenic property. According to the survival analysis of The Cancer Genome Atlas database, FOXD3-AS1 upregulation implied lower survival rate of patients with CRC. Quantitative real-time polymerase chain reaction showed the overexpression of FOXD3-AS1 in both CRC tissues and cells. The Kaplan–Meier method demonstrated the prognostic value of FOXD3-AS1 for patients with CRC. To explore the effect of FOXD3-AS1 on CRC progression, loss-of-function experiments were carried out, whose results indicated that knockdown of FOXD3-AS1 suppressed cell proliferation, migration, and invasion, inhibited cell cycle and promoted cell apoptosis in vitro. In vivo experiments affirmed that FOXD3-AS1 affected tumor growth. FOXD3-AS1 expression was enriched in the cytoplasm of CRC cells. Mechanism experiments revealed that FOXD3-AS1 served as a competing endogenous RNA to upregulate SIRT1 by sponging miR-135a-5p. In addition, SIRT1 silencing also restrained cell proliferation and motility. Rescue assays revealed the biological function of FOXD3-AS1/miR-135a-5p/SIRT1 axis in CRC progression. In conclusion, FOXD3-AS1 promotes CRC progression by regulating miR-135a-5p/SIRT1 axis, shedding lights on the way to CRC treatments.     

Knockdown of lncRNA ZFAS1-suppressed non–small cell lung cancer progression via targeting the miR-150-5p/HMGA2 signaling

Non–small cell lung cancer (NSCLC) is the main type of lung malignancy. Early diagnosis and treatments for NSCLC are far from satisfactory due to the limited knowledge of the molecular mechanisms regarding NSCLC progression. Long noncoding RNA (lncRNA) ZNFX1 antisense RNA1 (ZFAS1) has been implicated for its functional role in the progression of malignant tumors. This study aimed to determine the ZFAS1 expression from lung cancer clinical samples and to explore the molecular mechanisms underlying ZFAS1-modulated NSCLC progression. Experimental assays revealed that clinical samples and cell lines of lung malignant tumors showed an upregulation of ZFSA1. ZFAS1 expression was markedly upregulated in the lung tissues from patients with advanced stage of this malignancy. The loss-of-function assays showed that knockdown of ZFAS1-suppressed NSCLC cell proliferative, as well as invasive potentials, increased NSCLC cell apoptotic rates in vitro and also attenuated tumor growth of NSCLC cells in the nude mice. Further experimental evidence showed that ZFAS1 inversely affected miR-150-5p expression and positively affected high-mobility group AT-hook 2 (HMGA2) expression in NSCLC cell lines. MiR-150-5p inhibition or HMGA2 overexpression counteracted the effects of ZFAS1 knockdown on NSCLC cell proliferative, invasive potentials and apoptotic rates. In light of examining the clinical lung cancer samples, miR-150-5p expression was downregulated and the HMGA2 expression was highly expressed in the lung cancer tissues compared with normal ones; the ZFAS1 expression showed a negative correlation with miR-150-5p expression but a positive correlation with HMGA2 expression in lung cancer tissues. To summarize, we, for the first time, demonstrated the inhibitory effects of ZFAS1 knockdown on NSCLC cell progression, and the results from mechanistic studies indicated that ZFAS1-mediated NSCLC progression cells via targeting miR-150-5p/HMGA2 signaling.     

DDX17 induces epithelial-mesenchymal transition and metastasis through the miR-149-3p/CYBRD1 pathway in colorectal cancer

DEAD box helicase 17 (DDX17) has been reported to be involved in the initiation and development of several cancers. However, the functional role and mechanisms of DDX17 in colorectal cancer (CRC) malignant progression and metastasis remain unclear. Here, we reported that DDX17 expression was increased in CRC tissues compared with noncancerous mucosa tissues and further upregulated in CRC liver metastasis compared with patient-paired primary tumors. High levels of DDX17 were significantly correlated with aggressive phenotypes and worse clinical outcomes in CRC patients. Ectopic expression of DDX17 promoted cell migration and invasion in vitro and in vivo, while the opposite results were obtained in DDX17-deficient CRC cells. We identified miR-149-3p as a potential downstream miRNA of DDX17 through RNA sequencing analysis, and miR-149-3p displayed a suppressive effect on the metastatic potential of CRC cells. We demonstrated that CYBRD1 (a ferric reductase that contributes to dietary iron absorption) was a direct target of miR-149-3p and that miR-149-3p was required for DDX17-mediated regulation of CYBRD1 expression. Moreover, DDX17 contributed to the metastasis and epithelial to mesenchymal transition (EMT) of CRC cells via downregulation of miR-149-3p, which resulted in increased CYBRD1 expression. In conclusion, our findings not only highlight the significance of DDX17 in the aggressive development and prognosis of CRC patients, but also reveal a novel mechanism underlying DDX17-mediated CRC cell metastasis and EMT progression through manipulation of the miR-149-3p/CYBRD1 pathway.Subject terms: Cell migration, Metastasis     

miR-548c-5p inhibits colorectal cancer cell proliferation by targeting PGK1

Accumulating studies have implicated that microRNAs (miRNAs) are involved in the pathogenesis of colorectal cancer (CRC). However, the role of miR-548c-5p, a novel identified miRNA in malignancies, in colorectal carcinogenesis remains largely unknown. The present study is aimed to investigate the effect and molecular mechanism of miR-548c-5p in CRC by a sequence of cellular experiments. miR-548c-5p was significantly downregulated, whereas phosphoglycerate kinase 1 (PGK1), a key enzyme for glycolysis, was obviously upregulated in peripheral blood mononuclear cells and cancer tissues from patients with CRC. Besides, miR-548c-5p and PGK1 were negatively associated with each other. The luciferase reporter assay revealed that PGK1 was a targeted gene of miR-548c-5p. Moreover, the proliferation and generation of inflammatory cytokines (TNF-α and IL-6) were significantly inhibited in miR-548c-5p-overexpressed SW480 CRC cells stimulated by lipopolysaccharide (LPS). Accordingly, miR-548c-5p may serve as a cancer suppressor in CRC by targeting PGK1.     

Circular RNA ubiquitin-associated protein 2 enhances autophagy and promotes colorectal cancer progression and metastasis via miR-582-5p/FOXO1 signaling

Numerous circular RNAs (circRNAs) have been identified as vital regulators in various cancers. The newly reported circular RNA ubiquitin-associated protein 2 (circUBAP2) is a critical player in cell growth and metastasis in various types of cancers, although its role in colorectal cancer (CRC) has yet to be fully elucidated. We find that circUBAP2 is upregulated in CRC tissues and cell lines to induce autophagy both in vitro and in vivo. The effects of circUBAP2 on migration, invasion, and proliferation may be partially related to autophagy. Mechanistically, we uncover that circUBAP2 can directly interact with miR-582-5p and subsequently act as a microRNA sponge to regulate the expression of the miR-582-5p target gene forkhead box protein O1 (FOXO1) and downstream signaling molecules, which collectively advance the progression and metastasis of CRC. These results suggest that circUBAP2 acts as an oncogene via a novel circUBAP2/miR-582-5p/FOXO1 axis, providing a potential biomarker and therapeutic target for CRC management.     

miR-9-5p靶向Ambra1促进舌癌细胞增殖

miRNAs在肿瘤中异常表达,且与肿瘤的发生发展密切相关。目前发现,miR-9-5p在肿瘤中可能发挥原癌或抑癌效应,功能尚未完全阐述清楚。本文拟探讨miR-9-5p在舌癌中的作用。前期研究中收集10例舌癌组织及配对的癌旁组织,实时荧光定量PCR技术检测后发现,miR-9-5p在舌癌组织中的表达量显著高于癌旁组织,且其在舌癌细胞中的表达量也明显高于正常舌上皮细胞。此外,在舌癌细胞Tca8113中过表达miR-9-5p显著增加细胞的增殖能力。生物信息学预测及双荧光素酶报告基因实验证实,miR-9-5p可直接结合在自噬/苄氯素1调节因子1（activating molecule in beclin1-regulated autophagy, Ambra1）的 3′-UTR区域,靶向抑制Ambra1表达。Western印迹结果证实过表达miR-9-5p降低Ambra1的表达,反之亦然。Ambra1在舌癌细胞中的表达量显著低于正常舌上皮细胞。BrdU实验证实在舌癌细胞SCC-25中过表达Ambra1可显著抑制其增殖能力;相反,使用siRNA技术沉默Ambra1能够显著促进Tca8113细胞的增殖。在干预miR-9-5p的细胞中同时干预Ambra1的表达,结果发现Ambra1可显著逆转miR-9-5p对舌癌细胞增殖的促进作用。总之,miR-9-5p在舌癌中可能发挥原癌基因样作用,通过直接靶向抑制Ambra1表达进而促进舌癌细胞发生增殖。     

H3K27 acetylation-induced lncRNA EIF3J-AS1 improved proliferation and impeded apoptosis of colorectal cancer through miR-3163/YAP1 axis

Long noncoding RNAs (lncRNAs) are found to be aberrantly expressed and pose significant impacts in colorectal cancer (CRC), the most prevalent type malignancy in the gastrointestinal tract. This study aimed to find out the regulation of lncRNA EIF3J antisense RNA 1 (EIF3J-AS1) on CRC progression. Expressions of EIF3J-AS1, microRNA-3163 (miR-3163), and Yes-associated protein 1 (YAP1) in tissues and cells were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. Association of EIF3J-AS1 with CRC prognosis was analyzed through the online bioinformatics tool GEPIA. The biological function of EIF3J-AS1 in CRC was investigated by Cell Counting Kit-8, colony formation, caspase-3 activity, and TUNEL staining. Competitive endogenous RNA (ceRNA) network of EIF3J-AS1/miR-3163/YAP1 was determined by luciferase reporter and RNA immunoprecipitation assays. Results showed that EIF3J-AS1 was upregulated in CRC tissues and cell lines, indicating poor prognosis of CRC patients. The silence of EIF3J-AS1 led to reduced proliferation and facilitated apoptosis of CRC cells. Mechanistcally, EIF3J-AS1 was upregulated by cAMP-response element-binding protein-binding protein-mediated histone H3 on lysine 27 acetylation (H3K27ac) at the promoter region, and EIF3J-AS1 upregulated YAP1 expression through sponging miR-3163 in CRC cells. In conclusion, we first found that H3K27 acetylation-induced lncRNA EIF3J-AS1 improved proliferation and impeded apoptosis of colorectal cancer through the miR-3163/YAP1 axis, which might potentially provide a novel molecular-targeted strategy for CRC treatment.     

Exosomal miR-146a-5p and miR-155-5p promote CXCL12/CXCR7-induced metastasis of colorectal cancer by crosstalk with cancer-associated fibroblasts

C-X-C motif chemokine receptor 7 (CXCR7) is a newly discovered atypical chemokine receptor that binds to C-X-C motif chemokine ligand 12 (CXCL12) with higher affinity than CXCR4 and is associated with the metastasis of colorectal cancer (CRC). Cancer-associated fibroblasts (CAFs) have been known to promote tumor progression. However, whether CAFs are involved in CXCR7-mediated metastasis of CRC remains elusive. We found a significant positive correlation between CXCR7 expression and CAF activation markers in colonic tissues from clinical specimens and in villin-CXCR7 transgenic mice. RNA sequencing revealed a coordinated increase in the levels of miR-146a-5p and miR-155-5p in CXCR7-overexpressing CRC cells and their exosomes. Importantly, these CRC cell-derived miR-146a-5p and miR-155-5p could be uptaken by CAFs via exosomes and promote the activation of CAFs through JAK2–STAT3/NF-κB signaling by targeting suppressor of cytokine signaling 1 (SOCS1) and zinc finger and BTB domain containing 2 (ZBTB2). Reciprocally, activated CAFs further potently enhanced the invasive capacity of CRC cells. Mechanistically, CAFs transfected with miR-146a-5p and miR-155-5p exhibited a robust increase in the levels of inflammatory cytokines interleukin-6, tumor necrosis factor-α, transforming growth factor-β, and CXCL12, which trigger the epithelial–mesenchymal transition and pro-metastatic switch of CRC cells. More importantly, the activation of CAFs by miR-146a-5p and miR-155-5p facilitated tumor formation and lung metastasis of CRC in vivo using tumor xenograft models. Our work provides novel insights into CXCR7-mediated CRC metastasis from tumor–stroma interaction and serum exosomal miR-146a-5p and miR-155-5p could serve as potential biomarkers and therapeutic targets for inhibiting CRC metastasis.Subject terms: Cancer microenvironment, Colon cancer     

microRNA-16-5p suppresses cell proliferation and angiogenesis in colorectal cancer by negatively regulating forkhead box K1 to block the PI3K/Akt/mTOR pathway

MicroRNAs (miRNAs/miRs) have aroused increasing attention in colorectal cancer (CRC) therapy. This study is designed for a detailed analysis of the roles of miR-16-5p and forkhead box K1 (FOXK1) in cell angiogenesis and proliferation during CRC in addition to their underlying mechanisms. CRC tissues and colon cancer cell lines (SW620 and HCT8) were investigated. qRT-PCR and Western blot were utilized to evaluate miR-16-5p and FOXK1 expression. Following gain- and loss-of-function assays on miR-16-5p or FOXK1, the effects of miR-16-5p and FOXK1 were assessed on cell angiogenesis and proliferation in CRC cells. A dual-luciferase reporter assay was employed to evaluate the binding relationship of miR-16-5p and FOXK1. Western blot was used to determine the effects of miR-16-5p and FOXK1 on key molecules of the PI3K/Akt/mTOR pathway. Highly expressed FOXK1 and lowly expressed miR-16-5p were observed in CRC cells and tissues. miR-16-5p overexpression or FOXK1 knockdown reduced CRC cell proliferation and angiogenesis of human umbilical vein endothelial cells co-cultured with the supernatant of CRC cells, whereas miR-16-5p silencing or FOXK1 upregulation caused opposite trends. Additionally, miR-16-5p negatively modulated FOXK1 expression. The blockade of the PI3K/Akt/mTOR pathway was triggered by miR-16-5p overexpression or FOXK1 silencing. In conclusion, miR-16-5p hampers cell angiogenesis and proliferation during CRC by targeting FOXK1 to block the PI3K/Akt/mTOR pathway.Key words: microRNA-16-5p, forkhead box K1, PI3K/Akt/mTOR pathway, colorectal cancer, proliferation, angiogenesis     

Long noncoding RNA ABHD11-AS1 promote cells proliferation and invasion of colorectal cancer via regulating the miR-1254-WNT11 pathway

The purpose of our study was to investigate the effects of the long noncoding RNA (lncRNA) ABHD11-AS1 on colorectal cancer (CRC) progression and further explore its possible underlying mechanisms. In the study, we found that ABHD11-AS1 was highly expressed in CRC tissues and cell lines. High ABHD11-AS1 expression was correlated with poor overall survival of patients with CRC. ABHD11-AS1 knockdown reduced CRC cell proliferation, in vitro invasion, and in vivo tumor growth. Investigation of the underlying mechanism showed that ABHD11-AS1 could act as a molecular sponge of miR-1254, and WNT11 was a downstream target of miR-1254 in CRC. Moreover, there was a negative association between ABHD11-AS1 expression (or WNT11) and miR-1254 in CRC tissues. The rescue assays showed that WNT11 overexpression partially rescued the effects of ABHD11-AS1 inhibition on CRC progression. Thus, we demonstrated that ABHD11-AS1 promotes CRC progression through the miR-1254-WNT11 pathway, which provides a new insight into the therapeutic strategies for CRC.