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KAEWPIBOON, CHUTIMA,SRISUTTEE, RATAKORN,MALILAS, WARAPORN,MOON, JEONG,OH, SANGTAEK,JEONG, HYE GWANG,JOHNSTON, RANDAL N.,ASSAVALAPSAKUL, WANCHAI,CHUNG, YOUNG-HWA SPANDIDOS PUBLICATIONS 2015 MOLECULAR MEDICINE REPORTS Vol.11 No.3
<P>Despite efforts to develop efficient chemotherapeutic drug strategies to treat cancer, acquired drug resistance is a commonly encountered problem. In the present study, to investigate this phenomenon, human A549 lung cancer cells resistant to the topoisomerase inhibitor etoposide (A549RT???eto) were used and compared with A549 parental cells. A549RT???eto cells demonstrated increased resistance to etoposide???induced apoptosis when compared with A549 parental cells. Notably, A549RT???eto cells were observed to exhibit greater levels of histone deacetylase 4 (HDAC4), phospho???Stat1 and P???glycoprotein [P???gp; encoded by the multidrug resistance 1 (MDR1) gene], compared with A549 cells. To address whether HDAC4 protein is involved in etoposide resistance in A549 cells, A549RT???eto cells were treated with trichostatin A (TSA; an HDAC inhibitor) during etoposide treatment. The combined treatment was demonstrated to enhance etoposide???induced apoptosis and reduce expression levels of HDAC4, P???gp and phospho???Stat1. In addition, the suppression of Stat1 with siRNA enhanced etoposide???induced apoptosis and reduced the expression levels of HDAC4 and P???gp, suggesting that Stat1 is essential in the regulation of resistance to etoposide, and in the upregulation of P???gp. Notably, TSA treatment reduced P???gp transcript levels but Stat1 siRNA treatment did not, suggesting that P???gp is regulated by HDAC at the transcriptional level and by Stat1 at the post???transcriptional level. These results suggest that the upregulation of Stat1 and HDAC4 determines etoposide resistance through P???gp expression in human A549 lung cancer cells.</P>
Alu Methylation in Serum from Patients with Nasopharyngeal Carcinoma
Tiwawech, Danai,Srisuttee, Ratakorn,Rattanatanyong, Prakasit,Puttipanyalears, Charoenchai,Kitkumthorn, Nakarin,Mutirangura, Apiwat Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22
Background: Nasopharyngeal carcinoma (NPC) is a common cancer in Southern China and Southeast Asia. Alu elements are among the most prevalent repetitive sequences and constitute 11% of the human genome. Although Alu methylation has been evaluated in many types of cancer, few studies have examined the levels of this modification in serum from NPC patients. Objective: To compare the Alu methylation levels and patterns between serum from NPC patients and normal controls. Materials and Methods: Sera from 50 NPC patients and 140 controls were examined. Quantitative combined bisulfite restriction analysis-Alu (qCOBRA-Alu) was applied to measure Alu methylation levels and characterize Alu methylation patterns. Amplified products were classified into four patterns according to the methylation status of 2 CpG sites: hypermethylated (methylation at both loci), partially methylated (methylation of either of the two loci), and hypomethylated (unmethylated at both loci). Results: A comparison of normal control sera with NPC sera revealed that the latter presented a significantly lower methylation level (p=0.0002) and a significantly higher percentage of hypomethylated loci (p=0.0002). The sensitivity of the higher percentage of Alu hypomethyted loci for distinguishing NPC patients from normal controls was 96%. Conclusions: Alu elements in the circulating DNA of NPC patients are hypomethylated. Moreover, Alu hypomethylated loci may represent a potential biomarker for NPC screening.
Identification of Pancreatic Cancer in Biliary Obstruction Patients by FRY Site-specific Methylation
Angsuwatcharakon, Phonthep,Rerknimitr, Rungsun,Kongkam, Pradermchai,Ridtitid, Wiriyaporn,Ponauthai, Yuwadee,Srisuttee, Ratakorn,Kitkumthorn, Nakarin,Mutirangura, Apiwat Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.9
Background: Methylation at cg 16941656 of FRY is exclusively found in normal pancreatic tissue and has been proven to be specific for pancreatic-in-origin among several adenocarcinomas. Here, we investigated methylated DNA in the bile as a biomarker to differentiate the cause of obstruction between pancreatic cancer and benign causes. Materials and Methods: Bile samples of 45 patients with obstructive jaundice who underwent ERCP were collected and classified into pancreatic cancer (group 1) and benign causes (group 2) in 24 and 21 patients, respectively. DNA was extracted from bile and bisulfite modification was performed. After, methylation in cg 16941656 of FRY was identified by real-time PCR, with beta-actin used as a positive control. Results: Methylated DNA was identified in 10/24 (41.67%) and 1/21 (4.8%) of cases in groups 1 and 2, respectively (P= 0.012). The sensitivity, specificity, positive predictive value and negative predictive value to differentiate pancreatic cancer from benign causes were 42%, 95%, 91%, and 59%, respectively. Conclusions: Detecting a methylation at cg 16941656 of FRY in bile has high specificity, with an acceptable positive likelihood rate, and may therefore be helpful in distinguish pancreatic cancer from benign strictures.
조일래,정영화,고상석,Hye-Jin Min,Su Jin Kim,이양순,Eun-Hee Park,Srisuttee Ratakorn,전병학,Sangtaek Oh,Randal N. Johnston 생화학분자생물학회 2011 Experimental and molecular medicine Vol.43 No.2
It is not yet understood how the enhanced expression of pancreatic adenocarcinoma up-regulated factor (PAUF; a novel oncogene identified in our recent studies),contributes to the oncogenesis of pancreatic cells. We herein report that PAUF up-regulates the expression and transcriptional activity of β-catenin while the suppression of PAUF by shRNA down-regulates β-catenin. The induction of β-catenin by PAUF is mediated by the activities of Akt and GSK-3β, but inhibition of downstream ERK does not reduce β-catenin expression. To test whether PAUF emulates either the Wnt3a-mediated or the protein kinase A-mediated signaling pathway for the stabilization of β-catenin, we examined the phosphorylation status of β-catenin in the presence of PAUF compared with that of β-catenin during treatment with Wnt3a or dibutyryl cAMP, a cell permeable cyclic AMP analogue. PAUF expression induces phosphorylation at Ser-33/37/Thr-41 and Ser-675 of β-catenin but no phosphorylation at Ser-45,indicating that a unique phosphorylation pattern of β-catenin is caused by PAUF. Finally, the expression of PAUF up-regulates both cyclin-D1 and c-Jun, target genes of β-catenin, leading to a rapid proliferation of pancreatic cells; conversely decreased PAUF expression (by shRNA) results in the reduced proliferation of pancreatic cells. Treatment with hexachlorophene (an inhibitor of β-catenin) reduces the proliferation of pancreatic cells despite the presence of PAUF. Taken together, we propose that PAUF can up-regulate and stabilize β-catenin via a novel pattern of phosphorylation, thereby contributing to the rapid proliferation of pancreatic cancer cells.