MicroRNA-29a Promotes Pancreatic Cancer Growth by Inhibiting Tristetraprolin

Background/Aims: Doublecortin-like kinase 1 (DCLK1) is emerging as a tumor-specific stem cell marker in pancreatic cancer (PC). MicroRNA-195 (miR-195) plays an important role in many types of tumors. However, the roles of DCLK1 in cancer and miRNAs that directly regulate DCLK1 have not been elucidated. The goal of this study is to assess the effects of miR-195 on inhibiting DCLK1 and to clarify the regulating mechanism of miR-195-DCLK1 in PC cells. Methods: The expression of DCLK1 protein and miR-195 in PC tissues and adjacent healthy pancreatic tissues was detected by Western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR), respectively and the correlation between overall survival of PC patients and expression of DCLK1 was measured by Kaplan-Meier analysis. Bioinformatics tools were used to identify the target gene of miR-195. Effects of miR-195 and DCLK1 on proliferation and cell cycle of PC cells were analyzed by MTT, colony formation assays and flow cytometry. Transwell and wound-healing experiments were employed to examine the cellular migration and invasion. A xenograft mouse model was also used to test the effects of miR-195 on tumor growth and metastasis in vivo. Results: The expression level of DCLK1 and miR-195 shows an inverse correlation in PC tissues and cell lines. A higher DCLK1 level is associated with higher TNM (tumor, node, and metastasis) stage, higher rate of lymph node metastasis, and poor survival. Luciferase reporter assay shows that miR-195 directly targets DCLK1. Overexpression of miR-195 inhibits proliferation, migration and invasion of PC cells, whereas downregulation of miR-195 has an opposite role. These actions were similar to the effects of knockdown and overexpression of DCLK1, respectively. Conclusions: These data suggest that miR-195 has tumor suppressor roles in PC by targeting DCLK1. MiR-195-DCLK1 pathway may provide insight into PC progression and represent a novel, promising diagnostic and therapeutic target for PC.

Section: Discussionmentioning

confidence: 99%

“…A recent study has shown that deregulated expression of series miRNAs correlates with PC development [10]. Through the online tools and luciferase assay, we found that microRNA-195 ( miR-195 ) directly targets DCLK1 .…”

Section: Introductionmentioning

confidence: 98%

MicroRNA-195 Suppresses the Progression of Pancreatic Cancer by Targeting DCLK1

Zhou

Sun

et al. 2017

“…Recently, many studies have shown that miRNAs are involved in various diseases, including cancers [10-17]. Using high-throughput RNA sequencing and bioinformatics, an increasing number of functional miRNAs have been discovered, which might participate in tumor development and could provide novel targets for pancreatic cancer therapies [21, 22].…”

Section: Discussionmentioning

confidence: 99%

“…Functional studies indicate that miRNAs have important functions in tumor occurrence and development [10, 11]. Recent studies have revealed that miRNAs are associated with the risk of different cancers, such as lung cancer [12], colorectal cancer [13], bladder cancer [14], breast cancer [15], and pancreatic cancer [16, 17]. All of these researches have provided strong evidence that miRNAs play a key role during tumorigenesis and tumor progression.…”

Section: Introductionmentioning

confidence: 99%

MicroRNA Expression Profiling of Pancreatic Cancer Cell Line L3.6p1 Following B7-H4 Knockdown

Qian

Ling

et al. 2017

Background/Aims: Co-stimulating molecule B7-H4 regulates T cell-mediated immune responses, participates in tumor immune escape, and promotes the proliferation and metastasis of pancreatic cancer cells. However, the specific mechanisms are unclear. MicroRNAs (miRNAs) participated in the pathogenesis and progression of cancer. Methods: In this study, a microarray technique was used to screen B7-H4-related differentially expressed miRNAs in a pancreatic cancer cell line find those associated with pancreatic cancer. Using a miRCURY^TM LNA Array approach, we compared the miRNA expression profiles of L3.6p1 pancreatic cancer cells transfected with B7-H4 siRNA for 72 h with those transfected with non-target siRNAs. Results: B7-H4 siRNA significantly up-regulated 57 miRNAs and down-regulated 14 miRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analysis of predicted miRNA targets showed that these genes were mainly involved in protein binding, pathways in cancer, mitogen-activated protein kinase (MAPK) signaling pathway, and phosphatidylinositol 3-kinase-Akt (PI3K-Akt) signaling pathway. Conclusions: This is the first description of target genes of B7-H4, showing that miRNAs participate in the B7-H4 mediated regulation of oncogenicity and pathogenesis of pancreatic cancer. These results may help us better understand the role of B7-H4 in the progression of pancreatic cancer and its possible mechanisms. We also provide novel biomarkers for potential treatments of pancreatic cancer.

“…A great number of molecules have been implicated in the development and progression of pancreatic cancer, such as stat3 [23], FoxM1 [24], IL-1β and miR-29a [25]. Caveolin-1 (Cav-1), the major structural protein of plasma membrane invaginations [26], is a key signal transducer in various human cancers [27-29].…”

Section: Introductionmentioning

confidence: 99%

Krüppel-Like Factor 4 Inhibits Pancreatic Cancer Epithelial-to-Mesenchymal Transition and Metastasis by Down-Regulating Caveolin-1 Expression

Zhu

Wang

et al. 2018

Background/Aims: Krüppel-like factor 4 (KLF4), a member of the KLF family of zinc finger transcription factors, has been identified as a tumor suppressor gene in a variety of tumors. However, the molecular mechanisms by which KLF4 inhibits epithelial-to-mesenchymal transition (EMT) and metastasis in pancreatic cancer remain unclear. Methods: KLF4 expression in pancreatic cancer was analyzed using public datasets (Oncomine and The Cancer Genome Atlas). The expression of KLF4, caveolin-1 (Cav-1), E-cadherin, and vimentin, and their correlations with clinicopathological characteristics were evaluated by immunohistochemistry in pancreatic cancer tissues. The biological functions and underlying mechanisms of KLF4 expression on EMT and metastasis were also investigated in vitro and in vivo. Results: Public datasets showed that KLF4 expression was significantly decreased in pancreatic cancer and correlated with the depth of invasion and disease stage. The expression of KLF4, Cav-1, E-cadherin, and vimentin protein in pancreatic cancer tissues was closely associated with pathological grade, disease stage, and metastasis. KLF4 expression was also positively correlated with E-cadherin expression and negatively correlated with vimentin expression, whereas Cav-1 expression was negatively associated with E-cadherin expression and positively correlated with vimentin expression. Knockdown of KLF4 expression promoted EMT and facilitated pancreatic cancer cell growth and metastasis in vitro and in vivo. In addition, immunohistochemistry (IHC) results indicated that KLF4 expression was negatively correlated with Cav-1 expression. Furthermore, down-regulating KLF4 expression increased Cav-1 and vimentin expression and decreased E-cadherin expression. Mechanistically, KLF4 could transcriptionally inhibit Cav-1 expression by binding directly to the promoter domain of Cav-1. Conclusions: KLF4 inhibits pancreatic cancer EMT and metastasis by down-regulating Cav-1 expression, suggesting that the KLF4/Cav-1 signaling pathway may be a novel diagnostic and therapeutic target.