lab has published the first RhoA knockout mouse model and discovered an
essential role of RhoA GTPase in regulating cell mitosis. This work is leading
to a series of studies of RhoA physiologic and pathological functions in
mammals. (Melendez J, Stengel K, Zhou X, Chauhan BK, Debidda M, Andreassen P,
Lang RA, Zheng Y. RhoA GTPase is dispensable for actomyosin regulation
but is essential for mitosis in primary mouse embryonic
fibroblasts. J. Biol. Chem. 286(17):15132-7.
1. The Andreassen lab published a paper (F.
Zhang et al. Chromosoma. 110:1637-1649. 2010.) which demonstrated that
FANCJ acts in parallel with monoubiquitinated FANCD2, rather than strictly
downstream as previously believed. Further, FANCJ promotes chromatin access of
2. The Andreassen lab collaborated with the
group of Satoshi Namekawa in the Division of Reproductive Sciences at Cincinnati
Children's. This work on DNA damage response proteins in silencing of the sex
chromosomes in male germ cells was published in Genes & Development (Y.
Ichijima et al. MDC1 directs chromosome-wide silencing of the sex
chromosomes in male germ cells. Genes Dev. 25:959-971. May,
- We demonstrate that a new protocol of
pathogen inactivation using the alkylant S-303 provides a reasonable safety
level for stored red cell viability in vivo (Cancelas JA et al. Stored
red blood cell viability is maintained after treatment with a second-generation
S-303 pathogen inactivation process. Transfusion. May 13,
- We demonstrate that prion filtration as a novel system for
pathogen inactivation provides a reasonable safety level for stored red cell
viability and immunogenicity in vivo (Cancelas JA et al. Infusion of
P-Capt prion-filtered red blood cell products demonstrate acceptable in vivo
viability and no evidence of neoantigen formation.
Transfusion. Oct, 2011.)
- We demonstrate that riboflavin and UV
light may be used in stored, but not long-term stored, whole blood products
(Cancelas JA et al. In vivo viability of stored red blood cells derived
from riboflavin plus ultraviolet light-treated whole blood.
Transfusion. 51(7):1460-8. Jul, 2011.).
studies High-Grade Astrocytoma (HGA) and Oligodendroglioma (ODG), which are very
aggressive brain tumors in adults and children. We use a combination of novel
mouse models and human tumor studies to elucidate the biology of these tumors in
order to develop and test effective treatments for this disease. Studies with
genetically-engineered mouse models that develop HGA and ODG spontaneously to
explore the molecular signals and cooperating mutations that drive tumor growth.
We recently described our studies on some of these models (Chow LM et al.
Cooperativity within and among Pten, p53, and Rb pathways induces
high-grade astrocytoma in adult brain. Cancer Cell.
Thrombin-mediated proteolysis is central to the
control of hemostasis and thrombosis, but it is increasingly understood that
prothrombin and multiple thrombin substrates play a pivotal role in embryonic
development, tissue repair, malignancy, and inflammation. In collaborative
studies done with Dr. Matthew Flick (Flick et al. The development of
inflammatory joint disease is attenuated in mice expressing the anticoagulant
prothrombin mutant W215A/E217A. Blood. 117(23): 6326-6337.
2011.), we examined for the first time the in vivo consequences of the
expression of a re-engineered form of prothrombin, termed
prothrombinWE, with substrate specificity favoring the activation of
protein C (a protease with known anticoagulant and anti-inflammatory
properties). The expression of prothrombinWE was found to
significantly limit the development of inflammatory joint disease in mice
challenged with collagen-induced arthritis (CIA). Furthermore, the
administration of exogenous active recombinant thrombinWE also
suppressed the development of arthritis in wild-type mice. These studies provide
a proof-of-principle that pro/thrombin variants engineered with altered
substrate specificity may offer therapeutic opportunities for limiting
inflammatory disease processes.
The overarching goal of my research program is to understand the molecular regulation of hematopoietic cell functions. Specifically, we have been investigating the role of cell shape and cytoskeleton reorganization in modulating hematopoietic stem cell self renewal and engraftment, and neutrophil migration and trafficking. We have identified a new role for p190-B-RhoGAP as a regulator of hematopoietic stem cell self renewal and cell fate decision during cell division. Furthermore, we are now showing that p190-B may do so by fine tuning cytoskeleton/microtubule reorganization as well as epigenetic regulation of gene expression. Other research project is to dissect the process of cell migration in neutrophils. We recently showed that Cdc42 unexpectedly uses aMb2 integrin signaling for efficient directed migration. We have now dissected this mechanism in more detail and have uncovered a novel mechanism of neutrophil migration involving WASp, Lipid raft formation, CD11b and microtubules. (manuscript in preparation)
1. We have
demonstrated that introduction of a (pro)thrombin variant termed fII W215A/E217A
either genetically or pharmacologically can limit the development of arthritis
in mice. This work is presented in a manuscript in the journal Blood in
June of 2011 and was highlighted in an “Inside Blood” commentary. (Flick MJ,
Chauhan AK, Frederick M, Talmage KE, Kombrinck KW, Miller W, Mullins ES, Palumbo
JS, Zheng X, Esmon NL, Esmon CT, Thornton S, Becker A, Pelc LA, Di Cera E,
Wagner DD, Degen JL. The development of inflammatory joint disease is
attenuated in mice expressing the anticoagulant prothrombin mutant
W215A/E217A. Blood. 117(23):6326-6337. 2011.)
Progress has been made demonstrating that the coagulation factor fibrinogen
promotes S. aureus virulence by supporting pathogen adherence via the
bacterial receptor Clumping Factor A. A formal collaboration with Dr. Magnus
Hook at the Texas A&M Health Science Center has developed in association
with this work and new funding (NIH R01 AI020662 Consortium Agreement) has been
The Geiger lab published in 2010 on a the
finding that the Epidermal-Growth-Factor Receptor regulates mobilization of
hematopoietic stem cells from bone marrow into peripheral blood and that
pharmacological inhibition of EGFR signaling by the drug Erlotinib enhances
granulocyte-colony-stimulating factor induced mobilization of stem cells.
(Ryan MA, Nattamai KJ, Xing E, Schleimer, Daria D, Sengupta A, Köhler
A, Liu W, Gunzer M, Jansen M, Ratner N, Le Cras TD, Waterstrat A, Van Zant G,
Cancelas JA, Zheng Y, Geiger H. Pharmacological inhibition of EGFR
signaling enhances G-CSF induced hematopoietic stem cell mobilization.
Nat. Med. 16 (10). 1141-6. 2010.)
studied the role of Cdc42 in T cell development and function and revealed an
essential function of Cdc42 mediating IL7 signaling and T cell homeostasis (Guo
F, et al. Coordination of IL-7 receptor and T-cell receptor signaling by
cell-division cycle 42 in T-cell homeostasis. PNAS.
107(43):18505-10. 2010; Guo F, et al. Distinct roles of Cdc-42 in
thymopoiesis and effector and memory T cell differentiation. PLoS
One. 6(3):e18002. 2011.)
1. Development of
human induced pluripotent stem cells (iPSC) from human peripheral blood.
2. Development of clinical lentiviral transduction conditions for human CD34+
Mutations in BLM, a RecQ-like helicase, are linked
to the autosomal recessive cancer-prone disorder Bloom's syndrome. BLM
associates with topoisomerase (Topo) IIIα, RMI1, and RMI2 to form the BLM
complex that is essential for genome stability. Here we report the crystal
structures of multiple domains of RMI1-RMI2, providing direct confirmation of
the existence of three oligonucleotide/oligosaccharide binding (OB)-folds in
RMI1-RMI2. Our structural and biochemical analyses revealed an unexpected
insertion motif in RMI1N-OB, which is important for stimulating the dHJ
dissolution. We also revealed the structural basis of the interaction between
RMI1C-OB and RMI2-OB and demonstrated the functional importance of the RMI1-RMI2
interaction in genome stability maintenance. (Wang F, Yang Y, Singh TR, Busygina
V, Guo R, Wan K, Wang W, Sung P, Meetei AR, Lei M. Crystal structures of
RMI1 and RMI2, two OB-fold regulatory subunits of the BLM complex.
Structure. 18(9):1159-70. Sep 8, 2010.)
In FY2011 the Mulloy
lab published in Leukemia on a new mouse model that represents the
“next generation” mouse for use in leukemia xenografting. This mouse has been
licensed to Jackson Labs and is being released to the research community in July
2011. The Mulloy lab is currently using this model in chemotherapy studies in an
effort to understand chemoresistance and relapse, especially in AML. In other
work published in Blood, the lab has used a cooperating oncogene,
activated N-ras, to promote progression of AML1-ETO pre-leukemia. One long-term
goal of the Mulloy lab is to have various common cytogenetically defined
leukemia models functional in the human stem cell model system, to complement
studies that are done using murine genetic approaches. These recent studies
bring this goal closer to fruition.
Our research is focused on understanding at the molecular level the cycling of Ras. Our goal is to design small molecule modulators of oncogenic Ras in cancer.
of the cytoplasmic function of FANCA and FANCC proteins – The finding suggest
cytoplasmic function of FANCA and FANCC in leukemogenesis. We published this
work in J. Biol. Chem.
Identification of IL-3Ra as a cell
surface marker for leukemia-initiating cells (LICs) in FA AML patients - We
found that interleukin-3 receptor a (IL-3Ra) is a promising candidate as an
LIC-specific antigen for FA AML, which may serve a valuable therapeutic target.
We published the work in Blood.
1. Wood M, Rawe M,
Johansson G, Pang S, Soderquist RS, Patel AV, Nelson S, Seibel W, Ratner N,
Sanchez Y. Discovery of a small molecule targeting IRA2 deletion in
budding yeast and neurofibromin loss in malignant peripheral nerve sheath tumor
cells. Mol Cancer Ther. Sep, 2011.
To identify new
therapeutic approaches targeting neurofibromatosis, we screened the University
of Cincinnati small molecule library in NF1+/+ and NF1-/- MPNST sarcoma cell
lines and in budding yeast lacking the NF1 homologue IRA2 (ira2Δ). Using this
novel model system approach to identify and validate target pathways for cancer
cells in which NF1 loss drives tumor formation, here we describe UC1, a small
molecule that targets NF1-/- cell lines and ira2Δ budding yeast and identify a
possible target pathway for NF1-associated MPNST.
2. Wu J, Dombi E,
Jousma E, Scott Dunn R, Lindquist D, Schnell BM, Kim MO, Kim A, Widemann BC,
Cripe TP, Ratner N. Preclinical testing of Sorafenib and RAD001 in the
Nf(flox/flox);DhhCre mouse model of plexiform neurofibroma using magnetic
resonance imaging. Pediatr Blood Cancer. Feb 11, 2011.
We used magnetic resonance imaging (MRI) in collaboration with the Imaging
Resource Center to monitor neurofibroma development in the Nf1(flox/flox);
DhhCre mouse model of GEM grade I neurofibroma. The data demonstrate that
volumetric MRI analysis can be used to monitor the therapeutic effect in the
preclinical neurofibroma drug screening, mimicking current human clinical
testing, and suggest that Sorafenib might have clinical activity in some
1. Identified a novel regulatory
mechanism of TRAF6 protein stability by autophagy:
Jing Fang, Lyndsey
Bolanos, Garrett Rhyasen, Carmen Rigolino, Agostino Cortelezzi, Esther N. Oliva,
Mariella Cuzzola, Daniel Starczynowski, manuscript in preparation
2. Identified a novel gene, IRAK1, that is important in the maintenance of
Garrett Rhyasen, Lyndsey Bolanos, Jing Fang,
Carmen Rigolino, Agostino Cortelezzi, Esther N. Oliva, Mariella Cuzzola, Daniel
Starczynowski, manuscript in preparation
Han van der Loo
The Vector Production Facility manufactured 631 vector products and brought in $440K in revenue from GMP manufacturing and $103K in revenue from manufacturing of research-grade products. A total of 133 visitors toured the Translational Cores Facility.
We are currently writing two manuscripts describing the effect of Shp2 (PTPN11) mutations on brain development, specifically in the development of myelinating oligodendrocytes and the development of cortical projection neurons. These findings are significant because Shp2 is mutated in the RAS related disorders, Noonan and LEOPARD syndrome. Patients in both of these syndromes exhibit neurocognitive defects. We hope to understand the neurodevelopmental abnormalities that occur when Shp2 mutations are expressed and that this will provide evidence towards the developmental basis of the behavioral phenotypes.
preclinical therapeutic trials: Preclinical testing of Sorafenib and RAD001 in
the Nf(flox/flox); DhhCre mouse model of plexiform neurofibroma using magnetic
resonance imaging. (Wu J, Dombi E, Jousma E, Scott Dunn R, Lindquist D, Schnell
BM, Kim MO, Kim A, Widemann BC, Cripe TP, Ratner N. Preclinical testing
of Sorafenib and RAD001 in the Nf(flox/flox) ;DhhCre mouse model of plexiform
neurofibroma using magnetic resonance imaging. Pediatric Blood and
Cancer. In press, 2011.)