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Shandong Tao,1,2,* Lixiao Song,1,2,* Yuan Deng,1,2 Yue Chen,1,2 Yuye Shi,1,2 Yimin Gan,1,2 Zhikui Deng,1,2 Banghe Ding,1,2 Zhengmei He,1,2 Chunling Wang,1,2 Liang Yu1,2 1Department of Hematology, The Affiliated Huai’an No.1 People’s Hospital of Nanjing Medical University, Huai’an, Jiangsu 223300, People’s Republic of China; 2Key Laboratory of Hematology of Nanjing Medical University, Nanjing 210029, People’s Republic of China*These authors contributed equally to this workCorrespondence: Liang Yu; Chunling Wang 1 Huang River Road West, Huai’an, Jiangsu 223300, People’s Republic of ChinaTel/Fax +86-517 8087 2603Email yuliangha@163.com; wcl6506@163.comAbstract: Retinoic acid receptor gamma (RARG) belongs to the nuclear receptor superfamily and has 90% homology to RAR alpha (RARA) and RAR beta. The promyelocytic leukemia (PML)–RARA fusion gene has been implicated in acute promyelocytic leukemia (APL). RARG gene rearrangement has been identified in a rare subtype of acute myeloid leukemia (AML) that resembles APL. To date, only 10 cases of gene rearrangements involving RARG (nucleoporin [NUP] 98–RARG, promyelocytic leukemia protein–RARG, cleavage and polyadenylation-specific factor 6–RARG, or nucleophosmin [NPM] 1–RARG–NPM1) have been reported. These patients show characteristics similar to APL, including bone marrow morphology, coagulation abnormality, and immunophenotype; however, they are resistant to all-trans retinoic acid and arsenic trioxide treatment. Moreover, there is no optimal therapeutic regimen for this subtype of AML. In this study, we report the clinical presentation and experimental findings of a case of AML with NUP98–RARG gene fusion similar to APL and review other cases of RARG gene rearrangement described in the literature.Keywords: acute myeloid leukemia, acute promyelocytic leukemia, NUP98-RARG, RARG rearrangem

Kankan Chen, Yue Chen, Zhi Chen, Yuye Shi, Zhengmei He, Banghe Ding, Chunling Wang, Liang Yu Department of Hematology, the Affiliated Huaian No 1 People’s Hospital of Nanjing Medical University, Huaian, Jiangsu, China Abstract: The relapse and resistance to cytarabine (Ara-C) therapy is still a dominating obstacle to the successful clinical treatment of acute myeloid leukemia (AML). Recent studies have shown that dysregulation of miRNAs might modulate the resistance of cancer cells to anticancer drugs; yet, the mechanism is not fully understood. In this study, we showed a significant downregulation of miR-134 in human multidrug-resistant leukemia cells and relapsed/refractory AML patient samples. Overexpression of miR-134 sensitized K562/A02 and HL-60/ADM cells to Ara-C, inhibited cell colony formation, and enhanced the ability of Ara-C to induce apoptosis. Mechanistic analyses revealed that Mnks was a putative target of miR-134, which was inversely correlated with miR-134 expression in human multidrug-resistant leukemia cells and relapsed/refractory AML patient samples. Further investigation showed that miR-134 increased the antitumor effects of Ara-C through inhibiting phosphorylation of eukaryotic initiation factor 4E and downregulating Mcl-1 and bcl2, which was independent of p38 and Erk1/2 activation. Taken together, our results demonstrate that miR-134 plays a pivotal role in AML Ara-C resistance through increasing cell sensitivity to Ara-C and promoting apoptosis by targeting Mnks. Keywords: miR-134, acute myeloid leukemia, Mnks, eIF4E, apoptosis