Hypermethylation of theAKAP12Promoter is a Biomarker of Barrett's-Associated Esophageal Neoplastic Progression

Abstract

The A-kinase anchoring protein 12 (AKAP12) is a kinase scaffold protein with known tumor suppressor activity. Recently, AKAP12 promoter hypermethylation was reported in gastric and colorectal cancers. We examined AKAP12 promoter hypermethylation using real-time methylation-specific PCR in 259 human esophageal tissues. AKAP12 hypermethylation showed highly discriminative receiver-operator characteristic (ROC) curve profiles, clearly distinguishing esophageal adenocarcinoma (EAC) from esophageal squamous cell carcinoma and normal esophagus (P < 0.0001). AKAP12-normalized methylation values were significantly higher in Barrett's metaplasia (BE), dysplastic Barrett's, and EAC than in normal esophagus (P < 0.0000001). AKAP12 hypermethylation frequency was zero in normal esophagus but increased early during neoplastic progression, to 38.9% in BE from patients with Barrett's alone, 52.5% in dysplastic Barrett's metaplasia, and 52.2% in EAC. AKAP12 hypermethylation levels were significantly higher in normal esophageal epithelia from patients with EAC (mean = 0.00082) than in normal esophagi from patients without Barrett's or esophageal cancer (mean = 0.00007; P = 0.006). There was a significant correlation between AKAP12 hypermethylation and BE segment length, a known clinical neoplastic progression risk factor. In contrast, only 2 (7.7%) of 26 esophageal squamous cell carcinomas exhibited AKAP12 hypermethylation. Treatment of BIC and OE33 EAC cells with 5-aza-2'-deoxycytidine reduced AKAP12 methylation and increased AKAP12 mRNA expression. AKAP12 mRNA levels in EACs with unmethylated AKAP12 (mean = 0.1663) were higher than in EACs with methylated AKAP12 (mean = 0.0668). We conclude that promoter hypermethylation of AKAP12 is a common, tissue-specific event in human EAC, occurs early during Barrett's-associated esophageal neoplastic progression, and is a potential biomarker for the early detection of EAC.

Promoter hypermethylation of CDH13 is a common, early event in human esophageal adenocarcinogenesis and correlates with clinical risk factors

“…38 In our previous studies, the nel-like 1, tachykinin-1, somatostatin and AKAP12 genes were significantly more hypermethylated in LSBE than in SSBE. [17][18][19][20] Notably, in the current study, CDH13 methylation also showed a strong relationship to BE segment length. The mean NMV of CDH13 was significantly higher in LSBE than in SSBE.…”

“…30 Recently, we also found that both hypermethylation frequency and NMV of the nel-like 1, tachykinin-1, somatostatin and AKAP12 genes were higher in BE with accompanying EAC than in BE without accompanying EAC. [17][18][19][20] Interestingly, both CDH13 hypermethylation frequency and level were significantly higher in BE with than without accompanying EAC in the current study, suggesting that CDH13 is a biomarker of more ominous disease lurking nearby.…”

“…17,19,20,30,35 CDKN2A, ESR1 and MYOD1 were methylated only in BE from patients who possessed dysplasia or cancer in other regions of their esophagus, but not in patients with no evidence of progression beyond BE, while CALCA, MGMT and TIMP3 were methylated more frequently in normal stomach, normal esophageal mucosa and intestinal metaplasia from patients with distant dysplasia or esophageal cancer than from patients without dysplasia or cancer. 35 Previously, we demonstrated that hypermethylation of p16, RUNX3 and HPP1 in BE or LGD may represent independent risk factors for the progression of BE to HGD or EAC.…”

“…[16][17][18] Furthermore, there is a growing body of evidence showing that abnormal methylation of DNA can be an early event in carcinogenesis and can serve as an early cancer detection biomarker, 15 including in EAC. [17][18][19][20] Hypermethylation of CDH13 has been described in many human cancers, 8,14,[21][22][23][24][25][26][27][28][29] including ESCC 24,29 ; however, hypermethylation of CDH13 in precancerous lesions such as Barrett's metaplasia (BE), as well as in BE-associated EAC, is an area that still remains to be explored. We investigated hypermethylation of the CDH13 promoter by real-time quantitative methylation-specific PCR (qMSP) in 259 endoscopic esophageal biopsy specimens of differing histologies and correlated these data with clinicopathological features.…”

AKAP12 A kinase (PRKA) anchor protein 12

“…Prognosis Downregulation of AKAP12 due to promoter hypermethylation in gastric cancer (Choi et al, 2004) or in Barrett's esophagus (Jin et al, 2008). Oncogenesis Presumably, the loss of AKAP12's scaffolding activity for kinases such as Src and PKC result in hyperactivated pathways that contribute to oncogenic transformation, as shown in Su et al, 2010 andSu et al, 2013.…”