TKIs induce alternative spliced BCR-ABLIns35bp variant via inhibition of RNA polymerase Ⅱ on genomic BCR-ABL.
TKIs induce alternative spliced BCR-ABLIns35bp variant via inhibition of RNA polymerase Ⅱ on genomic BCR-ABL.
复制标题
TKI 通过抑制基因组 BCR-ABL 上的 RNA 聚合酶 Ⅱ 诱导选择性剪接的 BCR-ABLIns35bp 变异体。
DOI：
10.1111/cas.14424
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发表时间：
2020
期刊：
影响因子：
5.7
通讯作者：
Miyamoto T.
中科院分区：
文献类型：
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作者：
Yuda J;Odawara J;Minami M;Muta T;Kohno K;Tanimoto K;Eto T;Shima T;Kikushige Y;Kato K;Takenaka K;Iwasaki H;Minami Y;Ohkawa Y;Akashi K;Miyamoto T.
为了阐明天然BCR-ABLIns 35 bp和选择性剪接酪氨酸激酶抑制剂（TKI）耐药但功能死亡的BCR-ABLIns 35 bp变体的动态变化，在开始或停止TKI治疗后，通过深度测序对慢性粒细胞白血病（CML）患者的每种转录本进行了连续定量。因为使用常规PCR系统一起扩增两种转录物以测量国际标度（IS），所以使用深度测序方法来定量此类BCR-ABL变体。在初次诊断时，9例患者中有7例出现了一小部分具有BCR-ABLIns 35 bp的细胞，占总ISBCR-ABL的0.8%，对应于实际BCR-ABLIns 35 bp值为1.1539%IS。TKI可迅速降低天然BCR-ABLIns 35 bp，但不降低BCR-ABLIns 35 bp，导致BCR-ABLIns 35 bp比例的初始增加。此后，在TKI治疗过程中，天然BCR-AB和BCR-ABLIns 35 bp均逐渐降低，而TKI耐药BCR-ABLIns 35 bp阳性的小群体继续在低水平波动，可能低估了分子缓解（MR）。TKI停药后，54例患者的测序分析显示快速复发，显然来自天然BCR-ABL+克隆。然而，IS在MR4.0附近的低水平波动，标志着表达功能死亡BCR-ABLIns 35 bp的细胞的主要持续性，表明TKI恢复是不必要的。我们阐明了错误剪接BCR-ABLIns 35 bp的可能机制，发生在内含子8内的特定假剪接位点，TKI处理可通过抑制RNA聚合酶II磷酸化来增强。未发现剪接体基因突变。因此，监测IS功能性BCR-ABL提取BCR-ABLIns 35 bp将使我们正确评估MR状态，从而确定适当的治疗干预。
To elucidate dynamic changes in nativeBCR‐ABLand alternatively spliced tyrosine kinase inhibitor (TKI)‐resistant but function‐deadBCR‐ABLIns35bpvariant, following commencement or discontinuation of TKI therapy, each transcript was serially quantified in patients with chronic myeloid leukemia (CML) by deep sequencing. Because both transcripts were amplified together using conventional PCR system for measuring International Scale (IS), deep sequencing method was used for quantifying suchBCR‐ABLvariants. At the initial diagnosis, 7 of 9 patients presented a small fraction of cells possessingBCR‐ABLIns35bp, accounting for 0.8% of the total ISBCR‐ABL, corresponding to actualBCR‐ABLIns35bpvalue of 1.1539% IS. TKI rapidly decreased nativeBCR‐ABLbut notBCR‐ABLIns35bp, leading to the initial increase in the proportion ofBCR‐ABLIns35bp. Thereafter, both nativeBCR‐ABLandBCR‐ABLIns35bpgradually decreased in the course of TKI treatment, whereas small populations positive for TKI‐resistantBCR‐ABLIns35bpcontinued fluctuating at low levels, possibly underestimating the molecular response (MR). Following TKI discontinuation, sequencing analysis of 54 patients revealed a rapid relapse, apparently derived from nativeBCR‐ABL+clones. However, IS fluctuating at low levels around MR4.0 marked a predominant persistence of cells expressing function‐deadBCR‐ABLIns35bp, suggesting that TKI resumption was unnecessary. We clarified the possible mechanism underlying mis‐splicingBCR‐ABLIns35bp, occurring at the particular pseudo‐splice site within intron8, which can be augmented by TKI treatment through inhibition of RNA polymerase II phosphorylation. No mutations were found in spliceosomal genes. Therefore, monitoring IS functionalBCR‐ABLextractingBCR‐ABLIns35bpwould lead us to a correct evaluation of MR status, thus determining the adequate therapeutic intervention.