cAMP study

Project leader: Heidi Kiil Blomhoff

B cell precursor acute lymphoblastic leukaemia (BCP-ALL) is the most commonly occurring paediatric cancer. Prognosis varies with different cytogenetic subgroups with an overall survival rate of more than 90 % in children. Despite its relatively good prognosis, especially the paediatric forms, there is a steady search for new strategies to improve treatment effects and to prevent the undesired side effects on normal cells. Previous in vitro studies from our group (Naderi E. et.al., 2015; Naderi E. et.al., 2013; Naderi E. et.al., 2011) demonstrated that the second messenger cyclic adenosine mono-phosphate (cAMP), via protein kinase A (PKA), inhibits the tumour suppressive activity of p53, and thereby promotes leukaemogenesis and protection against therapy-induced leukemic cell death. In the present study we wish to confirm our in vitro results in vivo.

Our aims are:

1. Establish xenografts of BCP-ALL in NSG mice to study the role of cAMP signalling in development and treatment of these leukaemias. Xenografts of BCP-ALL are established by injecting the human blast cells into the bone marrow of NOD/SCID/IL2R gamma null (NSG) mice.
   
   In order to follow the fate of the leukemic cells, the blasts are transduced by a lentiviral vector encoding both enhanced green fluorescent protein (eGFP) (allowing in vitro analysis), and firefly Luciferase (fLuc) (for in vivo bioluminescent imaging) prior to injection as previously described (Bomken S. et al., 2013). This xenograft model mimics human ALL propagation and serves as a valuable tool for the development of anti-leukemic strategies.
   
   
2. Establish the role of PGE2 from bone marrow-derived stroma cells in development of BCP-ALL.
   
   We hypothesise that PGE2 from stroma cells induces cAMP signalling in leukemic cells, which in turn inhibits p53 production and drives the leukaemia development. We will study the development of BCP-ALL in xenograft mice in the presence or absence of indomethacin. Indometachin is a cox-inhibitor that inhibits the formation of PGE2, thereby preventing the PGE2-mediated cAMP signalling in the leukemic cells. We will also coinject the mice with the cAMP promoting agent forskolin, in order to establish that a possible inhibiting effect of indomethacin on leukaemia development is via reduced cAMP signalling in the leukemic cells.
   
   
3. Improve conventional treatment of BCP-ALLs by indomethacin.
   
   We will treat the xenograft mice with DNA damaging agents such as doxorubicin in the presence or absence of indomethacin, to reveal whether inhibiting the cAMP-signalling pathway will delay or prevent further development of the leukemia, hence improve the treatment of the leukemic mice.