Azacitidine induces demethylation of p16INK4a and inhibits growth in adult T-cell leukemia/lymphoma.
Azacitidine induces demethylation of p16INK4a and inhibits growth in adult T-cell leukemia/lymphoma.
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DOI：
10.3892/ijmm.2011.756
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发表时间：
2011-11
影响因子：
5.4
通讯作者：
K. Uenogawa;Y. Hatta;N. Arima;S. Hayakawa;U. Sawada;S. Aizawa;Tatsuo Yamamoto;J. Takeuchi
中科院分区：
文献类型：
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作者：
K. Uenogawa;Y. Hatta;N. Arima;S. Hayakawa;U. Sawada;S. Aizawa;Tatsuo Yamamoto;J. Takeuchi
成人T细胞白血病/淋巴瘤（ATL）是与人类T细胞白血病病毒I型（HTLV-1）密切相关的外周T细胞恶性肿瘤之一。虽然病毒反式激活蛋白Tax已被提出在白血病发生中发挥关键作用，但ATL的发展需要额外的细胞事件。肿瘤抑制基因的失活是该疾病的遗传事件之一。染色体9 p上的CDKN 2A基因座编码2种细胞周期调控蛋白p14 ARF和p16 INK 4a，它们使用不同的阅读框架共享外显子2。p14 ARF和p16 INK 4a基因在多种人类肿瘤中频繁突变、缺失或启动子高甲基化，因此被认为是肿瘤抑制基因。本文报道了p14 ARF和p16 INK 4a在9种ATL细胞系（MT 1、MT 2、OKM 3 T、F6 T、K3 T、Oh 13 T、S1 T、Su 9 T01和HUT 102）中的表达情况。逆转录聚合酶链反应（RT-PCR）结果显示，1株OKM 3 T细胞未检测到p14 ARF的表达，6株OKM 3 T、MT 1、MT 2、Oh 13 T、S1 T和Su 9 T01细胞均未检测到p16 INK 4a的表达。在OKM 3 T细胞系中，p14 ARF/p16 INK 4a基因的共享外显子2缺失;然而，p16 INK 4a基因在其他5个细胞系中表观遗传学失活。在从ATL患者获得的原发性肿瘤细胞中，11个样品中有6个不表达p14 ARF。我们使用甲基化特异性PCR（MSP）方法证实了MT 1和MT 2细胞中p16 INK 4a基因的甲基化。用2.0 μM阿扎胞苷（AZA）（一种去甲基化剂）处理72小时，恢复了MT 2细胞中p16 INK 4a转录本的表达，并诱导了生长抑制。我们的研究结果表明，p16 INK 4a是表观遗传沉默的ATL。AZA提供了一种潜在的新的治疗方法，以改善与ATL相关的不良结局。
Adult T-cell leukemia/lymphoma (ATL) is one of the peripheral T-cell malignant neoplasms strongly associated with human T-cell leukemia virus type-I (HTLV-I). Although the viral transactivator protein Tax has been proposed to play a critical role in leukemogeneis, additional cellular events are required for the development of ATL. One of the genetic events of the disease is inactivation of tumor suppressor genes. The CDKN2A locus on chromosome 9p encodes 2 cell cycle regulatory proteins, p14ARF and p16INK4a, which share exon 2 using different reading frames. The p14ARF and p16INK4a genes have been implicated as tumor suppressor genes by their frequent mutation, deletion or promoter hypermethylation in a variety of human tumors. In this report, we describe the expression status of p14ARF and p16INK4a in 9 ATL cell lines (MT1, MT2, OKM3T, F6T, K3T, Oh13T, S1T, Su9T01 and HUT102). By reverse transcription polymerase chain reaction (RT-PCR), expression of p14ARF was not detected in one cell line (OKM3T), while expression of p16INK4a was not detected in 6 cell lines (OKM3T, MT1, MT2, Oh13T, S1T and Su9T01). In the OKM3T cell line, the shared exon 2 of the p14ARF/p16INK4a gene was deleted; however, the p16INK4a gene, was epigenetically inactivated in 5 other cells lines. In primary tumor cells obtained from ATL patients, p14ARF expression was absent in 6 of the 11 samples. We confirmed the methylation of the p16INK4a gene in MT1 and MT2 cells using the methylation-specific PCR (MSP) method. Treatment with 2.0 µM of Azacitidine (AZA), a demethylating agent, for 72 h restored p16INK4a transcript expression and induced growth inhibition in MT2 cells. Our results demonstrate that p16INK4a is epigenetically silenced in ATL. AZA offers a potential new therapeutic approach to improve the poor outcomes associated with ATL.