Development of Polypeptide-based Nanoparticles for Non-viral Delivery of CD22 RNA Trans-splicing Molecule as a New Precision Medicine Candidate Against B-lineage ALL

Abstract

CD22ΔE12 has emerged as a driver lesion in the pathogenesis of pediatric B-lineage acute lymphoblastic leukemia (ALL) and a new molecular target for RNA therapeutics. Here we report a 43-gene CD22ΔE12 signature transcriptome that shows a striking representation in primary human leukemia cells from patients with relapsed BPL. Our data uniquely indicate that CD22ΔE12 is a candidate driver lesion responsible for the activation of MAPK and PI3-K pathways in aggressive forms of B-lineage ALL. We also show that the forced expression of a CD22 RNA trans-splicing molecule (RTM) markedly reduces the capacity of the leukemic stem cell fraction of CD22ΔE12+ B-lineage ALL cells to engraft and cause overt leukemia in NOD/SCID mice. We have successfully complexed our rationally designed lead CD22-RTM with PVBLG-8 to prepare a non-viral nanoscale formulation of CD22ΔE12-RTM with potent anti-cancer activity against CD22ΔE12+ B-lineage leukemia and lymphoma cells. CD22-RTM nanoparticles effectively delivered the CD22-RTM cargo into B-lineage ALL cells and exhibited significant anti-leukemic activity in vitro.

Identification and targeting of CD22ΔE12 as a molecular RNAi target to overcome drug resistance in high-risk B-lineage leukemias and lymphomas

“…These novel nanomaterials exhibit unprecedented thermodynamic and physicochemical stability and unique biological properties with exceptional endosomal escape and nucleic acid delivery efficiency. Our nanoscale siRNA delivery platform has been further optimized to enhance its translational impact potential [15–17] . We have complexed CD22ΔE12-siRNA with a 200-mer polymer of the lead helical polypeptide to prepare a nanoscale formulation of CD22ΔE12-siRNA.…”

Can we be SMaRT-er in our approach to cancer therapy?

“…These mutations result in aberrant splicing and loss of exon 12, leading to translation pre-termination and the generation of a truncated protein which lacks the regulatory domains required for proper signal transduction and apoptosis induction ( Uckun et al, 2010 ). Forced expression of human CD22ΔE12 in mice resulted in spontaneous development of B-ALL with a gene signature that closely recapitulates that of human ALL, indicating that CD22ΔE12 is an oncogenic driver ( Uckun et al, 2015a , Uckun et al, 2010 ). Because CD22ΔE12 is associated with aggressive and chemo-refractory disease, the authors sought to repair this defect by using SMaRT technology to replace the exons 10–14 of the mutant pre-mRNA with the wildtype sequence using a rationally designed RTM ( Uckun et al, 2015b ).…”

“…In this issue, Uckun et al take the concept of SMaRT-mediated repair back to its roots and explore its use in the repair of an oncogenic defect, CD22ΔE12, in childhood B-precursor leukemia (BPL), the largest subset of B-lineage acute lymphoblastic leukemia (ALL) ( Uckun et al, 2015a ). BPL cells express dysfunctional CD22, a principal negative regulator of B cell receptor signaling, due to homozygous intronic mutations.…”

“…Because CD22ΔE12 is associated with aggressive and chemo-refractory disease, the authors sought to repair this defect by using SMaRT technology to replace the exons 10–14 of the mutant pre-mRNA with the wildtype sequence using a rationally designed RTM ( Uckun et al, 2015b ). Transfection of the RTM into leukemia-initiating ALL cells significantly reduced their ability to cause leukemia in a xenograft animal model ( Uckun et al, 2015a ). This effect is presumably due to the repair and restoration of functional CD22, though this remains to be stringently demonstrated.…”

Value of Liberal Arts education in the Era of Precision Medicine

“…Data mining, bioinformatics, computational modeling and simulation have increasingly become integral to development of novel hypotheses in disease progression and potentially novel therapeutic innovations that target prominent receptors in leukemias (CD19 and CD22 receptors) to eradicate cancer cells. [14][15][16][17][18][19][20] Our project attempted to link data mining efforts that identify genetic signatures in high risk patient sub-groups to data explorations methods developed using R made available in Bioconductor (http://www.bioconductor. org/) by writing interactive, exploration based statistical analysis platform provided by Shiny applications (http://shiny.rstudio.com/).…”