EGF upregulates RFPL3 and hTERT via the MEK signaling pathway in non‑small cell lung cancer cells

Abstract

Activation of the epidermal growth factor receptor (EGFR) during tumor development can trigger the MEK signaling pathway. In the present study, we investigated the MEK signaling pathway in non-small cell lung cancer (NSCLC) cells with respect to the effect of epidermal growth factor (EGF) on expression of Ret finger protein like 3 (RFPL3) and human telomerase reverse transcriptase (hTERT), and the effect of RFPL3 overexpression on other MEK signaling proteins. In vitro, A549 and H1299 cells were treated with different concentrations of EGF for 24 h or 48 h. Expression of RFPL3 and hTERT at the mRNA and protein levels was determined by real-time quantitative PCR (RT-qPCR) and western blot analysis; cell viability was detected by MTT assay, and apoptosis was assayed via flow cytometry. We also pretreated A549 and H1299 cells with EGFR tyrosine kinase inhibitors, AG1478 and erlotinib, and MEK-specific inhibitor (PD98059) in the presence of EGF. We used western blot analysis to assess the expression levels of RFPL3, hTERT and related MEK-pathway proteins in A549 and H1299 cells transfected with RFPL3-overexpression plasmids. EGF significantly upregulated RFPL3 and hTERT protein levels in the NSCLC cells. RFPL3 and hTERT proteins upregulation by EGF were attenuated by pretreatment with AG1478 and erlotinib. EGF promoted proliferation and inhibited apoptosis; PD98059 decreased RFPL3 and hTERT protein expression; and RFPL3 overexpression increased the expression of hTERT and related MEK-pathway proteins. EGF upregulated RFPL3 and hTERT protein expression in NSCLC cells via the MEK pathway, promoted cell proliferation and inhibited apoptosis. RFPL3 overexpression increased expression of hTERT and related MEK signaling proteins (Ras, Raf, ERK and p-ERK), which implies that RFPL3 is a potential therapeutic target for NSCLC.

RETRACTED: RBFOX3 Promotes Gastric Cancer Growth and Progression by Activating HTERT Signaling

“…This study investigated whether RBFOX3 bound to the HTERT promoter interacted with other transcription factors. Previous studies showed that the HTERT promoter-binding proteins include KLF4 ( 21 ), RFPL3 ( 22 ), CPSF4 ( 23 ), and AP-2β ( 17 ). To test this possibility, we performed a Co-IP pull-down experiment and, using a RBFOX3-specific antibody, observed that RBFOX3 bound to AP-2β ( Figures 7A,B ).…”

Platelet-Activating Factor-Receptor Signaling Mediates Targeted Therapies-Induced Microvesicle Particles Release in Lung Cancer Cells

“…For this, we took advantage of a recent study, which identified that some NSCLC cell lines including A549 and H1299 express functional PAFR [ 38 ]. Besides, these cell lines also harbor wild-type EGFR, and have been used in studies with gefitinib and/or erlotinib [ 28 , 40 , 41 , 42 , 43 ].…”

Long non‑coding RNA RFPL3S is a novel prognostic biomarker in lung cancer

“…A previous study identified 1.2 kB non-coding antisense mRNAs of RFPL3S genes, which cover substantial portions of their sense counterparts, suggesting that RFPL3S is involved in the post-transcriptional regulation of the sense RFPL genes at different spatial and temporal windows, and no apparent Open Reading Frame or repetitive elements could be detected ( 33 ). RFPL3, belonging to the RFPL protein family (including RFPL1, RFPL2 and RFPL3) ( 33 ), can increase telomerase activity and length ( 62 ), and promote the proliferation of tumor cells by regulating the expression of the human telomerase reverse transcriptase (hTERT) gene in NSCLC cells and driving hTERT promoter transcription ( 63 ). Epidermal growth factor significantly increased the levels of RFPL3 and hTERT proteins in NSCLC cells via activation of the MEK signaling pathway, resulting in promoting proliferation ( 63 ).…”

“…RFPL3, belonging to the RFPL protein family (including RFPL1, RFPL2 and RFPL3) ( 33 ), can increase telomerase activity and length ( 62 ), and promote the proliferation of tumor cells by regulating the expression of the human telomerase reverse transcriptase (hTERT) gene in NSCLC cells and driving hTERT promoter transcription ( 63 ). Epidermal growth factor significantly increased the levels of RFPL3 and hTERT proteins in NSCLC cells via activation of the MEK signaling pathway, resulting in promoting proliferation ( 63 ). In addition, CREB binding protein has been identified to coordinate with RFPL3 to regulate hTERT promoter activity through acetylation to promote lung cancer cell growth ( 64 ).…”