SRPK1 inhibition and other treatments for acute myeloid leukaemia
Publication Date
July 16, 2024
Creator
Abstract
Acute Myeloid Leukaemia (AML) is a heterogeneous disease of haematopoietic stem cells. It is characterised by poor prognosis and many sub-types carry genetic alterations that make it harder to treat. The current treatment of AML takes heavy tolls on patients, especially on children, causing life changing consequences. AML usually appears in a de novo form, although there are multiple cases of therapy-related AML reported due to the use of temozolomide, that is used for the treatment of Glioblastoma Multiforme (GBM).
Previous studies showed that SRPK1 (serine/arginine rich splicing factor protein kinase 1) inhibition reduces AML burden in in vivo models of MLL-translocated cells, by prohibiting cell proliferation and causing cell cycle arrest. SRPK1 is known for its role in phosphorylating the serine/arginine rich proteins, especially SRSF1 (serine/arginine rich splicing factor 1), which then plays a role in alternative mRNA splicing. Six AML cell lines were tested, three of the AML cell lines carry an MLL translocation (MLL-TL with AF9, AF10 fusion genes) whilst the other three do not, and therefore classed as wild-type (MLL-WT). It has been reported that cells which carry a translocation are more sensitive to SRPK1 inhibitor treatment than cells without this genetic mutation. This thesis aims to demonstrate the efficacy of a known SRPK1 inhibitor, SPHINX-31, and other unpublished inhibitors for the treatment of AML and solid tumours.
As an off-target effect, SRPK1 has also been shown to alter survival and BRD4 (Bromodomain-containing protein 4) splicing in AML cells. It was shown that SPHINX-31 can change the BRD4 isoform in AML from the short (BRD4s), oncogenic, to the long (BRD4l), tumour-suppressive form and thus significantly halt cancer progression. To rule out confounding factors, other genes were also tested that are commonly overexpressed in cancer such as MYC, HOXA9, BCL-2 which all showed a decrease in expression in response to increasing levels of inhibitor treatment. To test the clinical relevance of these inhibitors primary AML cells were also treated with SPHINX-31 and Griffin 51 in colony forming units. The data showed promising results that were previously seen with AML cell lines, e.g. the BRD4s isoform is reduced, and all downstream targets are significantly decreased.
Cdc-like kinase 1 (CLK1) is known for its synergistic effect in combination with SRPK1 and their similar role in phosphorylating SR proteins, therefore the previous studies were repeated with a highly selective CLK1 inhibitor which also resulted in reduced cell viability and a significant decrease in all downstream targets. CLK1 inhibition caused a similar effect in BRD4 splice change, where increasing levels of a CLK1 inhibitor caused an upregulation in the tumour-suppressor BRD4l isoform and a down regulation in BRD4s isoform.
BRD4 has been found to be overexpressed not only in AML but in solid tumour cancers such as GBM. And often AML occurs as a side effect to therapy applied to treat GBM. As both AML and GBM have poor survival rates, there is a great unmet clinical need to find potential drug targets for both. To that end, SPHINX-31 and Griffin 51 were used to treat GBM cells and test their response to treatment. A 3D model of the Blood-Brain barrier was also created to mimic the natural environment of GBM.
Item Type
ethesis
Thesis Type
PhD
Supervisors
Subjects (LC)
Associated Schools / Departments
School of Life Sciences
eprints ID
77144
UoN Repository URI
Except where otherwise noted, this item's license is described as
File(s)![Thumbnail Image]()
Name
Thesis_Viola Erdelyi_2023.pdf
Type
Full-text
Description
Examined
Size
25.59 MB
Format
Adobe PDF
Checksum (MD5)
9704f4ba77fad8031a3aed1420baddea