scholarly journals The LncRNA EPEL Promotes Lung Cancer Cell Proliferation Through E2F Target Activation

2018 ◽  
Vol 45 (3) ◽  
pp. 1270-1283 ◽  
Author(s):  
Seong-Min Park ◽  
Eun-Young Choi ◽  
Dong-Hyuck Bae ◽  
Hyun Ahm Sohn ◽  
Seon-Young Kim ◽  
...  

Background/Aims: Recent studies have revealed that many long non-coding RNAs (lncRNAs) play oncogenic or tumor-suppressive roles in various cancers. Lung cancer is the leading cause of cancer-related death worldwide, and many lung cancer patients frequently relapse after surgery, even those in the early stages. However, the oncogenic or tumor-suppressive roles and clinical implications of lncRNAs in lung cancer have not been fully elucidated. Methods: The association between an E2F-mediated cell proliferation enhancing lncRNA (EPEL) expression and lung cancer patient survival was accessed using public microarray data with clinical information. Cancer-related phenotypes were analyzed by the siRNA knockdown of EPEL in two lung cancer cell lines. Gene set analysis of gene expression data were performed to identify pathways regulated by EPEL. RNA immunoprecipitation, RT-qPCR, and ChIP assays were performed to explore the functions of selected target genes regulated by EPEL. Results: EPEL, known as LOC90768 and MGC45800, was associated with the relapse and survival of lung cancer patients and promoted lung cancer cell proliferation through the activation of E2F target genes. EPEL knockdown specifically down-regulated the expression of cell cycle-related E2F target genes, including Cyclin B1 (CCNB1), in lung cancer cells but not that of apoptosis- or metabolism-related E2F target genes. EPEL interacted with E2F1 and regulated the expression of the E2F target genes by changing the binding efficiency of E2F1 to the E2F target promoters. Moreover, the expression levels of EPEL and CCNB1 both alone and in combination were robust prognostic markers for lung cancer. Conclusions: Considering its specific effects on cell cycle-related E2F target genes and its significant association with the prognosis of lung cancer patients, we suggest that the transcriptional regulation of EPEL through E2F target genes is potentially a target for the development of novel therapeutic strategies for lung cancer patients.

2020 ◽  
Vol 295 (18) ◽  
pp. 5906-5917
Author(s):  
Wei Huang ◽  
Paramita Ray ◽  
Wenbin Ji ◽  
Zhuwen Wang ◽  
Derek Nancarrow ◽  
...  

We previously reported that overexpression of cytochrome P450 family 24 subfamily A member 1 (CYP24A1) increases lung cancer cell proliferation by activating RAS signaling and that CYP24A1 knockdown inhibits tumor growth. However, the mechanism of CYP24A1-mediated cancer cell proliferation remains unclear. Here, we conducted cell synchronization and biochemical experiments in lung adenocarcinoma cells, revealing a link between CYP24A1 and anaphase-promoting complex (APC), a key cell cycle regulator. We demonstrate that CYP24A1 expression is cell cycle–dependent; it was higher in the G2-M phase and diminished upon G1 entry. CYP24A1 has a functional destruction box (D-box) motif that allows binding with two APC adaptors, CDC20-homologue 1 (CDH1) and cell division cycle 20 (CDC20). Unlike other APC substrates, however, CYP24A1 acted as a pseudo-substrate, inhibiting CDH1 activity and promoting mitotic progression. Conversely, overexpression of a CYP24A1 D-box mutant compromised CDH1 binding, allowing CDH1 hyperactivation, thereby hastening degradation of its substrates cyclin B1 and CDC20, and accumulation of the CDC20 substrate p21, prolonging mitotic exit. These activities also occurred with a CYP24A1 isoform 2 lacking the catalytic cysteine (Cys-462), suggesting that CYP24A1's oncogenic potential is independent of its catalytic activity. CYP24A1 degradation reduced clonogenic survival of mutant KRAS-driven lung cancer cells, and calcitriol treatment increased CYP24A1 levels and tumor burden in Lsl-KRASG12D mice. These results disclose a catalytic activity-independent growth-promoting role of CYP24A1 in mutant KRAS-driven lung cancer. This suggests that CYP24A1 could be therapeutically targeted in lung cancers in which its expression is high.


Phytomedicine ◽  
2019 ◽  
Vol 53 ◽  
pp. 124-133 ◽  
Author(s):  
Xuejiao Li ◽  
Zhuo Qu ◽  
Songsong Jing ◽  
Xia Li ◽  
Chengcheng Zhao ◽  
...  

2021 ◽  
Author(s):  
Kazuo Tsuchiya ◽  
Katsuhiro Yoshimura ◽  
Yuji Iwashita ◽  
Yusuke Inoue ◽  
Tsutomu Ohta ◽  
...  

Abstract Background: The modification of N6-methyladenosine (m6A) in RNA and its eraser ALKBH5, an m6A demethylase, play important roles across various steps of human carcinogenesis. However, the involvement of ALKBH5 in non-smallcell lung cancer (NSCLC) development remains to be completely elucidated.Methods: The current study investigated the involvement of ALKBH5 in NSCLC development using immunostaining of clinical NSCLC specimens as well as cancer-related cellular functions (cell proliferation, migration ability, cell cycle, and apoptosis) in ALKBH5-knockdown lung cancer cell lines. Moreover, a microarray was utilized to comprehensively analyze mRNA and m6A in ALKBH5-knockdown cells. m6A target genes were identified using the methylated RNA immunoprecipitation (MeRIP) assay with m6A antibody. Furthermore, mRNA stability and protein expression owing to m6A modification (the target genes) were examined.Results: Clinicopathological analysis revealed that increased ALKBH5 expression was an independent prognostic factor associated with unfavorable overall survival in NSCLC (hazard ratios, 1.468; 95% confidence interval, 1.039–2.073). In vitro study revealed that ALKBH5 knockdown suppressed cell proliferation ability of PC9 and A549 cells as well as promoted G1 arrest and increased the number of apoptotic cells. Furthermore, ALKBH5 overexpression increased the cell proliferation ability of the immortalized cell lines BEAS2B and HEK293. Comprehensive analysis of microarray and MeRIP quantitative-polymerase chain reaction revealed that 3′ untranslated regions (3′ UTRs) of CDKN1A, TIMP3, E2F1, and CCNG2 mRNA were potential targets of ALKBH5. Depending on the lung cancer cell lines, increased expression of CDKN1A or TIMP3 and decreased cell proliferation were observed by ALKBH5 knockdown.These alterations were offset by a double knockdown of both ALKBH5 and one of the IGF2BPs. The decline of mRNAs was, at least partly, owing to the destabilization of these mRNAs by one of the IGF2BPs.Conclusions:Upregulation of ALKBH5 in NSCLC reduces m6A modifications on the 3′ UTR of specific genes. Loss of m6A causes a decrease in opportunity for recognition by IGF2BPs and destabilizes the target transcript, such as CDKN1A (p21) and TIMP3. Downregulation of CDKN1A (p21) and TIMP3 induces cell cycle alteration and inhibits apoptosis. The ALKBH5–IGF2BPs axis promotes cell proliferation and tumorigenicity, which in turn causes the unfavorable prognosis of NSCLC.


Author(s):  
Man Zhang ◽  
Jie Tian ◽  
Rui Wang ◽  
Mengqiu Song ◽  
Ran Zhao ◽  
...  

Lung cancer is a leading cause cancer-related death with diversity. A promising approach to meet the need for improved cancer treatment is drug repurposing. Dasatinib, a second generation of tyrosine kinase inhibitors (TKIs), is a potent treatment agent for chronic myeloid leukemia (CML) approved by FDA, however, its off-targets and the underlying mechanisms in lung cancer have not been elucidated yet. LIM kinase 1 (LIMK1) is a serine/threonine kinase, which is highly upregulated in human cancers. Herein, we demonstrated that dasatinib dose-dependently blocked lung cancer cell proliferation and repressed LIMK1 activities by directly targeting LIMK1. It was confirmed that knockdown of LIMK1 expression suppressed lung cancer cell proliferation. From the in silico screening results, dasatinib may target to LIMK1. Indeed, dasatinib significantly inhibited the LIMK1 activity as evidenced by kinase and binding assay, and computational docking model analysis. Dasatinib inhibited lung cancer cell growth, while induced cell apoptosis as well as cell cycle arrest at the G1 phase. Meanwhile, dasatinib also suppressed the expression of markers relating cell cycle, cyclin D1, D3, and CDK2, and increased the levels of markers involved in cell apoptosis, cleaved caspase-3 and caspase-7 by downregulating phosphorylated LIMK1 (p-LIMK1) and cofilin (p-cofilin). Furthermore, in patient-derived xenografts (PDXs), dasatinib (30 mg/kg) significantly inhibited the growth of tumors in SCID mice which highly expressed LIMK1 without changing the bodyweight. In summary, our results indicate that dasatinib acts as a novel LIMK1 inhibitor to suppress the lung cancer cell proliferation in vitro and tumor growth in vivo, which suggests evidence for the application of dasatinib in lung cancer therapy.


2020 ◽  
Vol 40 (1) ◽  
Author(s):  
Yafeng Fan ◽  
Hongxia Li ◽  
Zhongping Yu ◽  
Wen Dong ◽  
Xiaoyan Cui ◽  
...  

Abstract Long non-coding RNA (lncRNA) FYVE, RhoGEF and PH domain containing 5 antisense RNA 1 (FGD5-AS1) has been reported as an oncogene in colorectal cancer, promoting its tumorgenesis. The present paper focused on searching the potential function of FGD5-AS1 in non-small cell lung carcinoma (NSCLC). There are connections between the expression of lncRNA FGD5-AS1 and human NSCLC tumor growth and progression. Also, the relationships between FGD5-AS1, hsa-miR-107 and mRNA fibroblast growth factor receptor like 1 (FGFRL1) are going to test their interaction in NSCLC cell lines, which may cause a series of biological behaviors of NSCLC cells. qRT-PCR analysis was conducted to test the expression of RNAs in different situation. CCK-8 experiment and clone formation assay were performed to assess proliferation of NSCLC cells. Also, connection between FGD5-AS1 and hsa-miR-107 were investigated by luciferase reporter assay and RNA pull-down assay. Rescue experiments were performed to verify the modulating relationship between FGD5-AS1, hsa-miR-107 and FGFRL1. High-level expression of FGD5-AS1 was found in NSCLC. FGD5-AS1 may promote the proliferation of NSCLC cells. Also, the combination between hsa-miR-107, FGD5-AS1 and NSCLC have been proved, which means they can play an interaction function in NSCLC cells. Thence, we concluded that lncRNA FGD5-AS1 promotes non-small cell lung cancer cell proliferation through sponging hsa-miR-107 to up-regulate FGFRL1.


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