Department of Laboratory Medicine (Laboratory Hematology) , Kawasaki Medical School

Research activities and research theme:@

(1) The myelodysplastic syndromes (MDS): from the molecular/cell biology to the diagnosis and nation-wide survey.

  

  Myelodysplastic syndromes (MDS) are acquired hematopoietic stem cell disorders characterized by dysplastic features of blood cells, irreversible therapy-resistant cytopenias and preleukemic states. In addition to the risk of transformation to the acute myeloid leukemia, most patients suffer from the bone marrow failure as a result of ineffective hematopoiesis.

  In our lab, molecular and cellular studies are being done by the use of unique MDS-derived cell lines, MDS92 and MDS-L, which carry chromosome 5q abnormality and monosomy 7. In particular, MDS-L cells were found to show growth inhibition exclusively by the treatment with lenalidomide, and therefore action mechanism of lenalidomide has been studied (Matsuoka A, et al: Leukemia, 2010). Just recently, Dr.Ebert and colleagues have demonstrated by the use of several cell lines including MDS-L that lenalidomide induces the ubiquitination of casein kinase 1A1 (CK1) by the E3-ubiquitin ligase CUL4-RBX1-DDB1-CRBN, resulting in CK1 degradation (Kronke J, et al: Nature 523:183-188, 2015).

  In addition, MDS-L cells are susceptible to DNA methyltransferase (DNMT) inhibitors and the effects of DNMT inhibitors and their underlying mechanisms are being investigated. We have raised a possibility that DNMT inhibitors activate cholesterol 25-hydroxylase(CH25H)-oxysterol pathway by their hypomethylating mechanism and induce cell death of myelodysplasia/leukemia cells (Tsujioka T, et al:Sci Rep 5: e16709, 2015 ).

  MDS-L cells are being utilized at a plenty of laboratories in various countries in addition to the above described studies. Striking data using MDS-L cells were presented by the group of Dr. Daniel T. Starczynowski at Cincinnati Childrenfs Hospital Medical Center. They produced an MDS xenograft model utilizing MDS-L cells (Rhyasen GW, et al: Cancer Cell 24:90-104, 2013; Rhyasen GW, et al: Leukemia 28:1142-1145, 2014). Similar in vivo trials are on-going at several laboratories.

  MDS92 and MDS-L cells probably have genetic instability and have brought several daughter cell lines which show reduced maturation. MDS-L cells proliferate in the presence of IL-3, but an IL-3-independent subline has recently been separated. From the set of MDS92 and subsequent daughter cell lines, a model can be raised that normal hematopoiesis, MDS phase and leukemic transformation (Kida J, et al: Leukemia, in press).

  We are also continuously involved in the nation-wide survey of MDS in Japan (eg. MDS with 5q abnormalities; Tasaka T, Tohyama K, et al: Leukemia, 2008; Tasaka T, Tohyama K, et al: Int J Hematol, 2011), and in the establishment of standardized diagnostic criteria.

MDS92 cell line

MDS92 cell line was established from the BM of an MDS(RAEB) patient and carries abnormal karyotypes including 5q- and -7. It was introduced as a unique and available, valid MDS cell line in Leukemia Research 33:1011-1016, 2009(by Drexler et al).

 

MDS-L cell line MDS-L cell lineifluorescence staining of nucleus and cytoskeletal structurej

MDS-L cell line

MDS-L is a blastic subline derived from the parental MDS92 and carries the similar karyotypes such as 5q- and -7.

MDS-L cell lineifluorescence staining of nucleus and cytoskeletal structurej

 

(2) Developmental research of laboratory hematology

  Morphological diagnosis of blood cells depends entirely on the observant eyes of the experienced hematologists or laboratory technologists, but cellular/molecular basis bringing various morphological abnormalities is poorly understood.

  We are aiming at a new horizon of laboratory hematology dealing with cell morphology through the analytical research of DNA contents or nuclear structures of the cells presenting abnormal morphology.

  Joint researches with the companies are also promoted as to development of automated analyzing system detecting minimal pathological cells in the blood and so on. Genetic diagnosis of hematological neoplasms (eg. JAK2 and calreticulin mutation) and analyses of red cell membrane abnormalities are also performed at our lab.

 

DNA ploidy of normal or abnormal neutrophils measured with laser-scanning cytometry