Knockout of both miR-15/16 loci induces acute myeloid leukemia

Abstract

MicroRNAs (miRNAs) have been extensively reported to be associated with hematological malignancies. The loss of miR-15a/16-1 at chromosome 13q14 is a hallmark of most of human chronic lymphocytic leukemia (CLL). Deletion of murine miR-15a/16-1 and miR-15b/ 16-2 has been demonstrated to promote B cell malignancies. Here, we evaluate the biological role of miR-15/16 clusters, crossbreeding miR-15a/16-1 and miR-15b/16-2 knockout mice. Unexpectedly, the complete deletion of both clusters promoted myeloproliferative disorders in the majority of the mice by the age of 5 months with a penetrance of 70%. These mice showed a significant enlargement of spleen and abnormal swelling of lymph nodes. Flow cytometry characterization demonstrated an expanded CD11b/Gr-1 double-positive myeloid population both in spleen and in bone marrow. The transplantation of splenocytes harvested from double-KO mice into wildtype recipient mice resulted in the development of myeloproliferative disorders, as observed in the donors. In vivo, miR-15/16 cluster deletion up-regulated the expression of Cyclin D1, Cyclin D2, and Bcl-2. Taken together, our findings identify a driver oncogenic role for miR-15/16 cluster deletion in different leukocytic cell lineages. miR-15/16 cluster | acute myeloid leukemia | mouse model T he loss of miR-15a/16-1 at chromosome 13q14, encoding two miRNAs residing in the same polycistrocnic RNA, is a hallmark of most of human chronic lymphocytic leukemias (CLL) (1). This dysregulation has been proved as the first evidence that genetic alteration in noncoding genes can cause malignancy (1).Most of CLLs are indolent but may progress to an aggressive disease. Analysis for mutations in many CLL showed that germline mutations just seven nucleotides 3′ of miR-16-1 are present in familial CLL (2), and this region was found to be necessary for processing of the miRNA precursor (3). Furthermore, the mouse strain NZB that develops an indolent CLL late in life carries a mutation six nucleotides 3′ of miR-16-1 affecting miR-15/16 processing, indicating that loss of function of miR-15a/16-1 leads to the development of indolent CLL (4). The frequency of loss of one or both miR-15a/16-1 clusters on chromosome 13q14 occurs in over 70% of the CLL patients and is the most common genetic alteration in CLL (1). Klein et al. (5) knocked out the miR-15a/16-1 locus in the mouse, and the knockout (KO) mice developed late in life the indolent form of CLL, as in human patients (6). Thus, loss of miR-15a/16-1 leads to the development of indolent CLL both in humans and mice. Since an additional locus of miR-15/16 exists on chromosome 3 (3q25), we have knocked out this second miR-15b/16-2 locus in the mouse (7). These mice developed mainly CLL and few diffuse large B cell lymphoma at higher penetrance (60%) and earlier age at 15-18 months (7) than the miR-15a/16-1 KO mice described by Klein et al. (5). Here, we evaluated the biological role of two different miR-15/16 clusters, crossbreeding miR-15a/16-1 and miR-15b/16-2 knockout (KO) mice. Unexpec...

6mer Seed Toxicity in Viral microRNAs

“…Although there was no v-miRNA with the same 6mer seed as miR-34a-5p, we found a v-miRNA that shared the same 2-7 nucleotides present in the predominant 5p arm of the miR-15/16-5p miRNA family. kshv-miR-K12-6-5p (miR-K12-6-5p) contains a GC-rich trinucleotide repeat seed sequence that is found in three miRNA families with ample published evidence for having tumor suppressive activities: miR-15/16-5p (Bonci et al, 2008;Calin et al, 2002Calin et al, , 2008Han et al, 2017;Hu et al, 2018;Huang et al, 2015;Ke et al, 2013;Klein et al, 2010;Lovat et al, 2015Lovat et al, , 2018Maximov et al, 2019;Pekarsky and Croce, 2015;Rahman et al, 2014;Yang et al, 2014), miR-214-3p (Cagle et al, 2019;Fan et al, 2017;Huang et al, 2014;Liu et al, 2016;Long et al, 2015;Pang et al, 2018;Phatak et al, 2016;Wang et al, 2012;Yang et al, 2015Yang et al, , 2018bZhang et al, 2017), and miR-103/107-3p Feng et al, 2012;Fu et al, 2019;Gao et al, 2017;Piao et al, 2012;Sharma et al, 2017;Song et al, 2015;Yamakuchi et al, 2010;Yang et al, 2018a;Zhang et al, 2019) (Figure 2A). miR-K12-6-5p shares an 8mer seed sequence with miR-15a-5p, miR-15b-5p, and miR-16-5p and a 6-, 7-, or 8mer seed with other members of this family (Figure 2A).…”

The oncogenic Kaposi’s sarcoma-associated herpesvirus encodes a mimic of the tumor suppressive miR-15/16 miRNA family

“…Downregulation of miR-15/16 has also been reported in other cancers. In mouse models, individual or combined deletion of the miR-15a/miR-16-1 and miR-15b/miR-16-2 clusters leads to hematologic malignancies (Klein et al, 2010;Lovat et al, 2015;Lovat et al, 2018). At the cellular level, miR-15/16 inhibit cell cycle progression and promote apoptosis and targets of miR-15/16 include strong candidates for mediators of its tumor suppressive properties, such as pro-apoptotic proteins of the BCL2 family (Cimmino et al, 2005), several cyclins, cyclin-dependent kinases, and other cell cycle regulators (Calin et al, 2008;Linsley et al, 2007;Liu et al, 2008).…”

Expression, Regulation and Function of microRNA as Important Players in the Transition of MDS to Secondary AML and Their Cross Talk to RNA-Binding Proteins

“…In contrast, concordant data are presented for miR-15/-16. In detail a double knockout of the two miR-15/-16 loci in mice caused the development of AML [ 104 ]. These results could be directly translated into humans, since BM probes from patients with MDS transforming into sAML or from patients with sAML expressed lower levels of both miRNAs when compared to corresponding samples from MDS patients [ 84 , 105 ].…”