H. Elizabeth Broome

Lis1 regulates asymmetric division in hematopoietic stem cells and in leukemia

Cell fate can be controlled through asymmetric division and segregation of protein determinants, but the regulation of this process in the hematopoietic system is poorly understood. Here we show that the dynein-binding protein Lis1 is critically required for hematopoietic stem cell function and leukemogenesis. Conditional deletion of Lis1 (also known as Pafah1b1) in the hematopoietic system led to a severe bloodless phenotype, depletion of the stem cell pool and embryonic lethality. Further, real-time imaging revealed that loss of Lis1 caused defects in spindle positioning and inheritance of cell fate determinants, triggering accelerated differentiation. Finally, deletion of Lis1 blocked the propagation of myeloid leukemia and led to a marked improvement in survival, suggesting that Lis1 is also required for oncogenic growth. These data identify a key role for Lis1 in hematopoietic stem cells and mark its directed control of asymmetric division as a critical regulator of normal and malignant hematopoietic development.

ROR1 is expressed on hematogones (non-neoplastic human B-lymphocyte precursors) and a minority of precursor-B acute lymphoblastic leukemia.

ROR1 is a receptor tyrosine kinase expressed during embryogenesis, on chronic lymphocytic leukemia (CLL) and in other malignancies. Hematogones (non-neoplastic B-lymphocyte precursors) express surface ROR1 at an intermediate stage of maturation that lacks CD34 or TdT. The neoplastic counterpart to hematogones is precursor-B acute lymphoblastic leukemia (B-ALL), but less than 10% of B-ALL express surface ROR1, and these ROR1+ B-ALL cases have an unusually high frequency of lacking CD34 and/or having t(1;19), a chromosomal translocation that defines a specific subtype of B-ALL.

Inhibition of Bcl-xL expression sensitizes T-cell acute lymphoblastic leukemia cells to chemotherapeutic drugs

We have examined the effects of antisense oligonucleotides to bcl-x on the survival and chemosensitivity of CEM cells, a T-acute lymphoblastic leukemia (T-ALL) cell line. Also, we have measured the levels of Bcl-2, Bcl-x, and Bax in 20 cases of T-ALL. By 18 h after the bcl-x antisense treatment, CEM cells showed over a 75% reduction in the levels of Bcl-xL protein and over 30% decreased viable cell counts compared with cells treated with the control oligonucleotide. The combination of bcl-x antisense plus either dexamethasone or doxorubicin showed either strong synergistic or additive killing of CEM cells, respectively. These findings indicate that bcl-x antisense has cytotoxic activity and increases chemotherapy-induced cell death in CEM cells, a model for T-ALL.

Sensitivity of S49.1 cells to anti-CD95 (Fas/APO-1)-induced apoptosis : effects of CD95, bcl-2 or bcl-x transduction

T lymphocytes have variable sensitivity to anti-CD95 which does not correlate closely with the level of CD95 expressed. To investigate this phenomenon, we screened murine T lymphocyte cultures for their sensitivity to anti-CD95. Subclones of the S49.1 cells showed widely variable sensitivity to anti-CD95 but similar levels of CD95. The resistant clones became sensitive after treatment with actinomycin D suggesting that they expressed resistance protein(s) with a high turnover relative to the CD95 apoptosis induction machinery. Our data suggest that the resistance protein(s) are not Bcl-2, Bcl-x, Fap-1 or Bag-1. Forced, increased expression of CD95 made most of the resistant cells more sensitive, but some remained resistant suggesting that the expression of the resistant protein(s) is heterogeneous and that increased CD95 levels does not always overcome the resistance.

Monoclonal antibodies in the treatment of hematologic malignancy

Methods to generate monoclonal antibodies to antigens of neoplastic cells have revolutionized our understanding of cancer cell growth and differentiation, diagnosis, and treatment. Monoclonal antibodies derived by immunizing animals (mostly mice) with mammalian cells or molecules have been critical reagents for the discovery and characterization of many key molecules involved in the behavior of neoplastic cells. Now, over 30 years later, monoclonal antibodies are widely used in the differential diagnosis of cancer and are key elements in the treatment of many forms of cancer. This review will focus on the roles that monoclonal antibodies play in the treatment of hematological malignancies. In particular, we will focus on acute myeloid leukemia and mature B-cell neoplasms.

t(4;22)(q12;q11.2) involving presumptive platelet-derived growth factor receptor A and break cluster region in a patient with mixed phenotype acute leukemia

The patient is a 45-year-old woman with a history of breast cancer who had been treated 1 year ago with radiation and chemotherapy. Flow cytometric analysis of bone marrow aspirate revealed 81% blasts positive for CD4, CD11c (partial), CD13, CD19 (partial), cytoplasmic CD22, CD34, CD36, CD45, cytoplasmic CD79a, CD117 (partial), HLA-DR, and terminal deoxynucleotide transferase, consistent with a mixed phenotype acute leukemia (B/myeloid lineage). Conventional karyotypic analysis revealed a t(4;22)(q12;q11.2) in 12 of 13 cells analyzed. Fluorescence in situ hybridization analysis using a dual-color, dual-fusion break cluster region/ABL probe set showed no break cluster region/ABL translocation but an extra break cluster region signal in 85% (170/200) of cells, consistent with a translocation involving the break cluster region gene at 22q11.2. A FIP1L1/CHIC2/platelet-derived growth factor receptor α deletion/fusion probe showed signal separation in 96.5% (193/200) of interphase nuclei. Reverse transcriptase-polymerase chain reaction using sense break cluster region primers and an antisense platelet-derived growth factor receptor α primer resulted in a product of approximately 590 base pairs, consistent with the presence of a break cluster region/platelet-derived growth factor receptor α fusion gene. Because of the presumptive platelet-derived growth factor receptor α translocation and its sensitivity to tyrosine-kinase inhibitor, the patient was treated with imatinib mesylate, cytarabine, and idarubicin as induction and maintenance therapy; and she has remained free of disease for 5 months since the initial diagnosis.

Myeloid neoplasm with t(3;8)(q26;q24): report of six cases and review of the literature

Abstract Balanced translocation between chromosomes 3q26 and 8q24 is a very rare event. Here we report six patients with t(3;8)(q26;q24) either as a sole or as a part of genetic abnormalities. Five of the six patients were men with ages ranging from 41 to 84 years old. One patient had a long history of granulocyte colony stimulating factor (G-CSF) treatment. Three of the patients were initially diagnosed with acute myeloid leukemia, two with myelodysplastic syndrome and one with chronic myelogenous leukemia with blast crisis. The peripheral blood in all patients showed severe to moderate anemia; one had absolute neutropenia, one with neutrophilia; four had thrombocytopenia, two with thrombocytosis. The bone marrows from all patients showed dysmegakaryopoiesis with additional erythroid (three patients) and granulocytic (two patients) dysplasia. Cytogenetics revealed t(3;8)(q26;q24) as the sole abnormality in three patients. The majority of patients (4/6) had a poor clinical course, with an average survival of 10 months.

A rare and unique case of aggressive IgE-λ plasma cell myeloma in a 28-year-old woman presented initially as an orbital mass

A 28-year-old African-American woman presented with new onset of left exophthalmos and diplopia. Computed tomography of the head showed a solitary mass in the left orbit. Excisional biopsy revealed a diffuse infiltrate composed of exclusively λ-restricted monotypic plasma cells based on morphology and immunohistochemistry, consistent with a plasma cell neoplasia. A subsequent staging bone marrow biopsy showed involvement of the bone marrow by λ-restricted monotypic plasma cells, consistent with a plasma cell myeloma. Serum protein electrophoresis and immunofixation studies on the peripheral blood showed a monoclonal band of IgE-λ; thus, an IgE-λ plasma cell myeloma was established. Additional clinical and radiologic workups showed multiple lytic bone lesions, diffuse lymphadenopathy, a pelvic mass, multiple mesenteric soft tissue nodules, and multiple pulmonary nodules, although none of the aforementioned sites was biopsied. The patient was treated with a combination of multiple chemotherapeutic agents and localized radiation due to the aggressive nature of the disease. To the best of our knowledge, this is the first case of an IgE plasma cell myeloma in a patient under the age of 30 years old presenting as a mass in an extramedullary site.

Successful treatment of both double minute of C-MYC and BCL-2 rearrangement containing large B-cell lymphoma with subsequent unfortunate development of therapy-related acute myeloid leukemia with t(3;3)(q26.2;q21)

Double minute chromosomes (DMs), although relatively frequently encountered in solid tumors, are rare in hematologic neoplasms such as acute myeloid leukemia (AML), and even rarer in lymphoid neoplasms. t(3;3)(q26.2;q21) is a very rare genetic alteration observed in myeloid neoplasm. Herein we report an interesting and unique case of concomitant C-MYC DMs and t(14;18)-containing large B-cell lymphoma, which was successfully treated with R-hyper-CVAD; unfortunately, the patient has developed a therapy-related AML (t-AML) 2 years since the start of his lymphoma treatment. His t-AML contains both t(3;3)(q26.2;q21) and monosomy 7, and the patient died of AML 10 months after the initial diagnosis of t-AML despite clinical remission. To the best of our knowledge, this is the first reported case of C-MYC DM-containing de novo large B-cell lymphoma, which was successfully treated with complete remission, but unfortunately died of t-AML harboring t(3;3)(q21;q26).

JAK2 double minutes with resultant simultaneous amplification of JAK2 and CD274 in a therapy-related myelodysplastic syndrome evolving into an acute myeloid leukaemia

Bachas, C., Schuurhuis, G.J., Hollink, I.H., Kwidama, Z.J., Goemans, B.F., Zwaan, C.M., van den Heuvel-Eibrink, M.M., de Bont, E.S., Reinhardt, D., Creutzig, U., de Haas, V., Assaraf, Y.G., Kaspers, G.J. & Cloos, J. (2010) High-frequency type I/II mutational shifts between diagnosis and relapse are associated with outcome in pediatric AML: implications for personalized medicine. Blood, 116, 2752–2758. Balgobind, B.V., Raimondi, S.C., Harbott, J., Zimmermann, M., Alonzo, T.A., Auvignon, A., Beverloo, H.B., Chang, M., Creutzig, U., Dworzak, M.N., Forestier, E., Gibson, B., Hasle, H., Harrison, C.J., Heerema, N.A., Kaspers, G.J., Leszl, A., Litvinko, N., Lo Nigro, L., Morimoto, A., Perot, C., Pieters, R., Reinhardt, D., Rubnitz, J.E., Smith, F.O., Stary, J., Stasevich, I., Strehl, S., Taga, T., Tomizawa, D., Webb, D., Zemanova, Z., Zwaan, C.M. & van den Heuvel-Eibrink, M.M. (2009) Novel prognostic subgroups in childhood 11q23/MLL-rearranged acute myeloid leukemia: results of an international retrospective study. Blood, 114, 2489–2496. Balgobind, B.V., Hollink, I.H., Arentsen-Peters, S.T., Zimmermann, M., Harbott, J., Beverloo, H.B., von Bergh, A.R., Cloos, J., Kaspers, G.J., de Haas, V., Zemanova, Z., Stary, J., Cayuela, J.M., Baruchel, A., Creutzig, U., Reinhardt, D., Pieters, R., Zwaan, C.M. & van den HeuvelEibrink, M.M. (2011) Integrative analysis of type-I and type-II aberrations underscore the genetic heterogeneity of pediatric acute myeloid leukemia. Haematologica, 96, 1478–1497. Coenen, E.A., Zwaan, C.M., Stary, J., Baruchel, A., de Haas, V., Stam, R.V., Reinhardt, D., Kaspers, G.J., Arentsen-Peters, S.T., Meyer, C., Marschalek, R., Lo Nigro, L., Dworzak, M., Pieters, R. & van den Heuvel-Eibrink, M.M. (2014) Unique BHLHB3 overexpression in pediatric acute myeloid leukemia with t(6;11)(q27;q23). Leukemia, 96, 1478–1487. Emerenciano, M., Barbosa, T. da C., de Almeida Lopes, B., Meyer, C., Marschalek, R. & Pombo-deOliveira, M.S. (2015) Subclonality and prenatal origin of RAS mutations in KMT2A(MLL)rearranged infant acute lymphoblastic leukaemia. British Journal of Haematology, 170, 268–271. Liang, D.C., Chen, S.H., Liu, H.C., Yang, C.P., Yeh, T.C., Jaing, T.H., Hung, I.J., Hou, J.Y., Lin, T.H., Lin, C.H. & Shih, L.Y. (2018) Mutational status of NRAS, KRAS and PTPN11 genes is associated with genetic/cytogenetic features in children with B-precursor acute lymphoblastic leukemia. Pediatric Blood & Cancer, 65, e26786. Meshinchi, S., Stirewalt, D.L., Alonzo, T.A., Zhang, Q., Sweetser, D.A., Woods, W.G., Bernstein, I.D., Arceci, R.J. & Radich, J.P. (2003) Activating mutations of RTK/ras signal transduction pathway in pediatric acute myeloid leukemia. Blood, 102, 1474–1479. Pession, A., Masetti, R., Rizzari, C., Putti, M.C., Casale, F., Fagioli, F., Luciani, M., Lo Nigro, L., Menna, G., Micalizzi, C., Santoro, N., Testi, A.M., Zecca, M., Biondi, A., Pigazzi, M., Rutella, S., Rondelli, R., Basso, G. & Locatelli, F. (2013) Results of the AIEOP-AML 2002/01 multicenter prospective trial for the treatment of children with acute myeloid leukemia. Blood, 122, 170–178. Stieglitz, E., Taylor-Weiner, A.N., Chang, T.Y., Gelston, L.C., Wang, Y.D., Mazor, T., Esquivel, E., Yu, A., Seepo, S., Olsen, S., Rosenberg, M., Archambeault, S.L., Abusin, G., Beckman, K., Brown, P.A., Briones, M., Carcamo, B., Cooper, T., Dahl, G.V., Emanuel, P.D., Fluchel, M.N., Goyal, R.K., Hayashi, R.J., Hitzler, J., Hugge, C., Liu, Y.L., Messinger, Y.H., Mahoney, D.H. Jr, Monteleone, P., Nemecek, E.R., Roehrs, P.A., Schore, R.J., Stine, K.C., Takemoto, C.M., Toretsky, J.A., Costello, J.F., Olshen, A.B., Stewart, C., Li, Y., Ma, J., Gerbing, R.B., Alonzo, T.A., Getz, G., Gruber, T., Golub, T., Stegmaier, K. & Loh, M.L. (2015) The genomic landscape of juvenile myelomonocytic leukemia. Nature Genetics, 47, 1326–1333. Wiemels, J.L., Kang, M., Chang, J.S., Zeng, L., Kouyoumji, C., Zhang, L., Smith, M.T., Scelo, G., Metayer, C., Buffler, P. & Wiencke, J.K. (2010) Backtracking RAS mutations in high hyperdiploid childhood acute lymphoblastic leukemia. Blood Cells, Molecules and Diseases, 45, 186–191.