The Functional Role And Mechanism Of Long Non-coding RNA In Papillary Thyroid Carcinoma Metastasis And Invasion

Objective: Emerging evidence indicates that the dysregulation of long non-coding RNA(Lnc RNA)plays critical roles in the progression of papillary thyroid carcinoma(PTC).Method: The differential high expression of Lnc RNA in 20 pairs PTC tissues were screened out by RNA sequencing,and verified in PTC cohort,3 GEO and 1 TCGA cohort;CCK8 assay was used to detect the proliferation of PTC cells(TPC-1 and KTC-1)transfected with si RNA;Wound healing and Transwell test were used to detect the migration and invasion ability of PTC cells transfected with si RNA;Zebrafish xenotransplantation tumor models were used to evaluate the effect of candidate Lnc RNA on metastasis of PTC cells;Bioinformatics analyze downstream signal pathway of candidate Lnc RNA;Western blot assay,RNA-pull down assay and luciferase reporter assay were used to study the relationship between candidate Lnc RNA and their downstream signaling molecules.Results: We found consistently elevated expression levels of the Lnc RNA-FAM230 B in PTC tissues,both in PTC verification cohort and in datasets from the GEO and TCGA databases.We demonstrated that the expression of Lnc RNA-FAM230 B can be used for the diagnosis of PTC and was also strongly associated with lymph node metastasis.Functionally,Lnc RNA-FAM230 B promoted the migration and invasion of PTC cells in vitro and in vivo.Mechanistically,Lnc RNA-FAM230 B sponged mi R-378a-3p and showed competitive binding to the 3’-UTR of WNT5 A.Lnc RNAFAM230 B overexpression resulted in elevated WNT5 A expression,thereby upregulated the EMT-related transcription factors TWIST1 and Vimentin and downregulated E-cadherin in PTC cells.Finally,we verified that both mi R-378a-3p overexpression and WNT5 A silencing effectively offset the impacts of Lnc RNAFAM230 B on PTC cell migration and invasion.Conclusion: Our study demonstrated the oncogenic function of the Lnc RNAFAM230 B in PTC cells,providing a promising target for PTC diagnosis and therapy.Objective: Our previous study found that Lnc RNA-n384546 was elevated expressed in PTC,and was significantly correlated with the occurrence and development of PTC.Hypoxic microenvironment can regulate the expression of Lnc RNA and promote tumor progression,but the roles in PTC and their mechanisms remain unclear.This study intends to detect the expression of HIF-1α in PTC tissue to make sure the hypoxic microenvironment in PTC tumor tissues.Furthermore,the influence of hypoxic microenvironment on the expression of Lnc RNA-n384546 and its effect and mechanism on tumor invasion were investigated in PTC cell.Method: Western blot assay was used to detect HIF-1α expression in PTC tumor tissue samples.The hypoxia microenvironment of PTC cell culture was established by adjusting the proportion of N2 and CO2 in the three-gas incubator,q PCR and Western blot assay were used to detect the expression of Lnc RNA-n384546 and HIF-1α respectively,Transwell assay and Western blot assay were used to detect the migration and invasion in PTC cells silencing Lnc RNA-n384546 under hypoxia microenvironment.The downstream signal molecules of Lnc RNA-n384546 in hypoxia microenvironment were predicted according to the literature.QPCR,Western blot assay,RNA-pull down assay,Chip q PCR assay were used to study the relationship between the expression of Lnc RNA-n384546 and its downstream signal molecules in hypoxia microenvironment.Results: HIF-1α was up-regulated in PTC tissues;In hypoxic microenvironment,the expression of Lnc RNA-n384546 was elevated expression and positively correlated with HIF-1α,Functionally,silencing Lnc RNA-n384546 resulted in down-regulation of EMT-key Vimentin,High Mobility Group at-hook 1(HMGA1)and up-regulation p53 in PTC cells,Silencing HGMA1 in hypoxic microenvironment resulted in downregulation of Vimentin expression and decreased invasion and migration of PTC cells.Mechanistically,Lnc RNA-n384546 suppressed the transcriptional activity of p53 by up-regulating HMGA1,which physically interacts with p53 to restrain transcription of its downstream genes.Furthermore,we found that Lnc RNA-n384546 forms an interactome with IGF2BP2 in order to sustain HMGA1 expression.Conclusion: Our study found that Lnc RNA-n384546 functions as an oncogene in PTC under hypoxic stress by blocking the IGF2BP2/HMGA1/p53-dependent pathway,and is a promising therapeutic target.