Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Background: Alteration of DNA methylation is an important event in pathogenesis and progression of hepatocellular carcinoma (HCC). DNA methyltransferase (DNMT) 1, the foremost contributor in DNA methylation machinery, was revealed elevated in HCC and significantly correlates with poor prognosis. However, the transcriptional regulation of DNMT1 in HCC remains unknown.
Methods: Real-time PCR and immunohistochemistry were performed to detect DNMT1 and zinc finger transcription factor 191 (ZNF191) expressions in HCCs. Transcription activity of DNMT1promoter was analyzed with Luciferase reporter activity assay. The binding capacity of ZNF191 protein to DNMT1 promoter was examined with chromatin immunoprecipitation-qPCR (ChIP-qPCR) and electrophoretic mobility shift assay (EMSA). DNA methylation level of hepatoma cells was detected with Methylation array.
Results: ZNF191 can regulate DNMT1 mRNA and protein expression positively, and increase the transcription activity of the DNMT1 promoter. ChIP-qPCR and EMSA revealed that ZNF191 protein directly binds to the DNMT1 promoter at nt-240 AT(TCAT) TC. Moreover, DNMT1 and ZNF191 expression correlate positively in human HCCs. With methylation array, DNA methylation alteration was observed in hepatoma cells with ZNF191 knockdown, and the differential methylation sites are enriched in the PI3K-AKT pathway. Furthermore, we proved DNMT1 contributes the effect of ZNF191 on hepatoma cell growth via the PI3K-AKT pathway.
Conclusion: ZNF191 is a novel transcription regulator for DNMT1, and the pro-proliferation effect of ZNF191/DNMT1/p-AKT axis in hepatoma cells implies that ZNF191 status in HCCs may affect the therapeutic effect of DNMTs inhibitors and PI3K inhibitors for precise treatment of the disease.
Download full-text PDF |
Source |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8894703 | PMC |
http://dx.doi.org/10.1002/cam4.4535 | DOI Listing |
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