Zhongguo aizheng zazhi (Apr 2022)
A study on correlation of acetyltransferase KAT3b and ABCE1 acetylation in esophageal cancer
Abstract
Background and purpose: Esophageal cancer is one of the main causes of cancer death in China, and the morbidity and death rates have remained high. Epigenetic acetylation modifications are involved in and regulate the proliferation, invasion and metastasis of a wide variety of tumor cells, and the acetylation modification of tumor proteins mediated by acetyltransferases may be one of the important mechanisms for esophageal carcinogenesis. This study investigated the expression of acetyltransferase 3b (KAT3b) and the ATP-combined box transporter E1 (ABCE1) acetylation level in esophageal cancer and analyzed the correlation and molecular mechanism in the pathogenesis of esophageal cancer. Methods: Fifty-five esophageal cancer tissue samples and 55 para-cancerous mucosal tissues were collected in Affiliated Hospital of Chengde Medical College from January 2020 to May 2021. The protein expressions of ABCE1 and KAT3b were measured by immunohistochemistry and Western blot. The acetylation level of ABCE1and KAT3b protein expression were determined by coimmunoprecipitation (Co-IP). Bioinformatics predicts the acetylation transferase KAT3b undergoing acetylation using ABCE1 as a substrate, and fluorescence immunohistochemistry (IF) verified the location and expressions of ABCE1 and KAT3b in cancerous tissues. The correlation between ABCE1 acetylation and KAT3b and their relationship with the clinical pathology characteristics were analyzed by statistics. RNA interference sequence of KAT3b for downregulation was constructed, and then transfected into esophageal cancer EC109 cells using liposome-mediated methods. The KAT3b mRNA expression and protein levels were determined by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) and Western blot. ABCE1 protein acetylation levels were detected using Co-IP experiments. Results: Protein expressions of ABCE1 and KAT3b were significantly higher compared with normal esophageal mucosa (P<0.05). The ABCE1 protein was acetylated in esophageal cancer tissue, and the level of ABCE1 protein acetylation was significantly higher in cancer tissues than in normal mucosal tissues (P<0.05). Bioinformatics predicts that the acetyltransferase KAT3b could catalyze the acetylation of ABCE1 as a substrate, and IF confirmed that ABCE1 and KAT3b proteins exhibited a high expression state in cancerous tissues. The ABCE1 acetylation levels and the KAT3b expression were correlated in esophageal cancer tissues, and they were correlated positively. ABCE1 acetylation and KAT3b were associated with esophageal cancer stage, tissue differentiation and lymph node metastasis, and were independent of gender and age. The in vitro experiments showed that the expressions of KAT3b mRNA and protein were inhibited after RNA interference of KAT3b in esophageal cancer cells, and the ABCE1 protein acetylation levels were also decreased significantly. Conclusion: There is correlation between KAT3b and ABCE1 protein acetylation in pathogenesis of esophageal cancer. Highly expressed KAT3b may be an important upstream molecule that catalyze acetylation of ABCE1 and have important potential value in the diagnosis and treatment of esophageal cancer.
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