Fig. 1: Phenotypic characterization of human HPRT3, HPRT2, and HPRT1 Richter Transformation PDX models.

A RT-DLBCL cells from PDX models were cytospun onto glass slides at 500 rpm utilizing a cyto-centrifuge. Cells were fixed with Fast Green and stained with hematoxylin and eosin. Original magnification is ×40. Cell images were obtained with a CCD camera mounted on a microscope. B Representative cell cycle status histograms of HPRT3, HPRT2, and HPRT1 cells. RT-DLBCL cells were harvested, washed with 1× PBS and fixed in 70% molecular grade ethanol overnight at −20 °C. Following this, RT-DLBCL cells were washed with 1× PBS and stained with 1 mg/mL propidium iodide in Triton-PBS buffer. Cells were analyzed by flow cytometry. C RT-DLBCL cells were harvested and stained with the indicated cell surface markers or the corresponding IgG isotype control. The numbers beside the histograms indicate the % of cells expressing each surface marker relative to the IgG isotype control. D Immunohistochemical evaluation of c-Myc, KI-67, and TP53 expression in RT cells. E HPRT3, HPRT2, and HPRT1 cells were luciferized to enable tracking of their in vivo growth in NSG mice. Representative images of engrafted luciferase-expressing RT-DLBCL PDX cells 4 weeks after cell implantation are shown. The total flux (photons/sec) from 2 to 3 mice with each PDX is shown. F Representative spleens from HPRT1, HPRT2, and HPRT3-engrafted mice compared to a normal mouse spleen approximately 6 weeks after cell implantation. The range of spleen sizes from 3 mice with each PDX model is shown in the violin plot.