Page 163 - Haematologica May 2020

Resistance to Notch1 neutralizing antibody
between saturated and (poly-) unsaturated lipids and identified a trend towards reduction of the unsaturation degree in OMP52M51-resistant samples (Figure 4B). Notably, acute treatment of PDTALL19 mice with OMP52M51 did not cause significant alterations in lipids (Online Supplementary Figure S12), indicating that dis-reg- ulated lipid metabolism is a feature of resistance.
A
Since NOTCH1 is a membrane-bound protein, we hypothesized that a different composition of lipid con- stituents could affect the fluidity of the membrane and the surface levels of the receptor. To this end, we ana- lyzed NOTCH1 protein levels by Western blot (WB) analysis both in whole cell lysates (Figure 5A) and in plas- ma membrane fractions (Figure 5B). OMP52M51-resis-
B
Figure 4. Lipidomic analysis of OMP52M51-resistant PDTALL19 cells. (A) The length of the columns is proportional to the abundance of analytes in the corresponding class. Numbers near columns represent the number of metabolites included in the analysis (right) and the sig- nificant ones (middle) for each class. Metabolites significantly less abundant in resistant cells are represented in red, instead the more abundant are in green (adjusted P-value<0.05, five samples/group). (B) An overview of significant less abundant (left) and more abundant (right) lipid metabolites in resistant cells. Lipids are schematically represented depending on their sat- uration degree.
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