LINE-1 ORF-1p enhances the transcription factor activity of pregnenolone X receptor and promotes sorafenib resistance in hepatocellular carcinoma cells

Abstract

BackgroundLINE-1 ORF-1p is encoded by the human pro-oncogene LINE-1. Our previous work showed that LINE-1 ORF-1p could enhance the resistance of hepatocellular carcinoma (HCC) cells to antitumor agents. However, the mechanisms involved in LINE-1 ORF-1p-mediated drug resistance remain largely unknown.Materials and methodsThe endogenous mRNA level of LINE-1 ORF-1p in clinical HCC specimens was examined using quantitative PCR (qPCR). The prognosis of HCC patients was assessed using time to progression and overall survival. The transcription factor activity of pregnenolone X receptor (PXR) was examined using luciferase gene reporter assays, qPCR, chromatin immunoprecipitation assays and cellular subfraction assays. Protein interaction between LINE-1 ORF-1p and PXR was detected by co-immunoprecipitation. The effect of LINE-1 ORF-1p on sorafenib resistance in HCC cells was studied using in vitro and in vivo models.ResultsA high level of LINE-1 ORF-1p in clinical specimens was related to poor prognosis in patients who received sorafenib treatment. LINE-1 ORF-1p increased the transcription factor activity of PXR by interacting with PXR and enhancing its cytoplasmic/nuclear translocation, and recruiting PXR to its downstream gene promoter, in turn enhancing the expression of the sorafenib resistance-related genes, CYP3A4 and mdr-1. LINE-1 ORF-1p enhanced the resistance to and clearance of sorafenib in HCC cells.ConclusionLINE-1 ORF-1p enhances the transcription factor activation of PXR and promotes the clearance of and resistance to sorafenib in HCC cells.

MicroRNA-3163 targets ADAM-17 and enhances the sensitivity of hepatocellular carcinoma cells to molecular targeted agents

“…The collection of HCC clinical specimens and methods were approved by the Ethic Committee of the Fifth Medical Center of General Hospital, Chinese People's Liberation Army (formerly named the 302nd Hospital, Chinese People's Liberation Army). The HCC patients provided written informed consent for the collection and usage of specimens, which were previously described (Supplementary Table 1) 31,32 . A total of 52 patients were included and real-time quantitative PCR (qPCR) was performed to examine the expression of genes in clinical specimens.…”

Profiling of LINE-1-Related Genes in Hepatocellular Carcinoma

“…These L1-specific antibodies might be a helpful tool for immunohistological analysis of HCC samples. Recently, ORF1p was shown to enhance the transcription factor activity of pregnenolone X receptor and to be involved in sorafenib-resistance in HCC cells [139]. The involvement of ORF1p in drug resistance in HCC further emphasizes the importance of evaluation of the ORF1p expression.…”

<p>Chelidonine enhances the antitumor effect of lenvatinib on hepatocellular carcinoma cells</p>

“…Following the administration of 10 doses over a 21-day period, the livers of mice with tumor tissues (ie, lesions/nodules) were harvested and collected. The photographs of livers were quantitatively analyzed using the Image J software (National Institutes of Health, Bethesda, MD, USA) as descripted by Xie et al (2018) and Chen et al (2018) 34,39. The intrahepatic growth of MHCC97-H cells was measured by calculating the relative lesion/nodule area as follows: (total intensity of lesion)/(total intensity of liver organ) ×100%.…”

“…The intrahepatic growth of MHCC97-H cells was measured by calculating the relative lesion/nodule area as follows: (total intensity of lesion)/(total intensity of liver organ) ×100%. The inhibition rates of agents on the intrahepatic growth of MHCC97-H cells were calculated as follows: [(control group relative lesion/nodule area) − (administration group relative lesion/nodule area)]/(control group relative lesion/nodule area) ×100% 34,39Table 4Weight of Tumor tissues seeded into nude mice’s liver organTumor tissuesWeight of Tumor tissues (mg)Solvent controlChelidonineLenvatinibChelidonine + LenvatinibNo.…”