Long Non-Coding RNA THOR Depletion Inhibits Human Non-Small Cell Lung Cancer Cell Growth

Abstract

Long non-coding RNA (LncRNA) THOR (Lnc-THOR) is expressed in testis and multiple human malignancies. Lnc-THOR association with IGF2BP1 (IGF2 mRNA-binding protein 1) is essential for stabilization and transcription of IGF2BP1 targeted mRNAs. We tested its expression and potential functions in non-small cell lung cancer (NSCLC). In primary NSCLC cells and established cell lines, Lnc-THOR shRNA or CRISPR/Cas9-mediated knockout (KO) downregulated IGF2BP1 target mRNAs (IGF2, Gli1, Myc and SOX9), inhibiting cell viability, growth, proliferation, migration and invasion. Significant apoptosis activation was detected in Lnc-THOR-silenced/-KO NSCLC cells. Conversely, ectopic overexpression of Lnc-THOR upregulated IGF2BP1 mRNA targets and enhanced NSCLC cell proliferation, migration and invasion. RNA-immunoprecipitation and RNA pull-down assay results confirmed the direct binding between Lnc-THOR and IGF2BP1 protein in NSCLC cells. Lnc-THOR silencing and overexpression were ineffective in IGF2BP1-KO NSCLC cells. Forced IGF2BP1 overexpression failed to rescue Lnc-THOR-KO NSCLC cells. In vivo, intratumoral injection of Lnc-THOR shRNA adeno-associated virus potently inhibited A549 xenograft tumor growth in nude mice. At last we show that Lnc-THOR is overexpressed in multiple NSCLC tissues and established/primary NSCLC cells. Collectively, these results highlighted the ability of Lnc-THOR in promoting NSCLC cell growth by associating with IGF2BP1, suggesting that Lnc-THOR represents a promising therapeutic target of NSCLC.

Targeting sphingosine kinase 1/2 by a novel dual inhibitor SKI-349 suppresses non-small cell lung cancer cell growth

“…The anti-tBid was provided by Abcam (ab10640). Other antibodies in this study were reported previously [ 21 , 22 ]. K6PC-5 was provided by Dr. Liu at Jiangsu University [ 23 ].…”

“…The fluorescence dyes utilized in the study were described previously [ 21 , 22 ]. Annexin V-propidium iodide (PI) FACS (fluorescence-activated cell sorting) kit was purchased from Thermo-Fisher Invitrogen Co. (Shanghai, China).…”

“…The immortalized NSCLC cell lines, A549 and NCI-H1944, the patient-derived primary human NSCLC cells, pNSCLC-1, pNSCLC-2 and pNSCLC-3 (derived from three different written-informed consent patients), as well as the BEAS-2B lung (bronchial) epithelial cells and the primary human lung epithelial cells were described in our previous studies [ 21 , 22 ]. A549, NCI-H1944 and BEAS-2B cells were maintained in DMEM medium plus 8–10% FBS.…”

High Expression of lncRNA HEIH is Helpful in the Diagnosis of Non-Small Cell Lung Cancer and Predicts Poor Prognosis

“…33 LncRNA interacts with many transcription factors and affects lung cancer growth and spread. 13,34 To date, many lncRNAs have been shown to be associated with the diagnosis and prognosis of NSCLC. 35 It was reported that lncRNA DNS-AS1 up-regulated the protein level of anti-apoptotic factor Bcl-2 and promoted the growth, migration, and invasion of LUAD cells.…”

“…12 More and more evidence indicates the involvement of lncRNAs in the pathogenesis and development of NSCLC. 13,14 For instance, lncRNA FeZF1-AS1 is up-regulated in lung cancer and promotes NSCLC through the ITGA11/miR-516b-5p axis; 15 LncRNA LCAT1, as an oncogene, can inhibit the growth of lung cancer cells and inhibit the tumorigenesis and metastasis of xenograft mice after knockout. 16 Additionally, lncRNA PCAT6 is highly expressed in NSCLC as an oncogene, and knockdown of PCAT6 inhibits NSCLC cell growth by inducing cell cycle arrest and apoptosis at the G1 phase.…”