Figure 4. PTPRZ1 knock-down impairs glioma growth in vivo.

Suspensions of E98 or E434 cells expressing PTPRZ1 shRNA and TagRFP (shPTPRZ1/TagRFP⁺) or control shRNA and EGFP (shSCR/EGFP⁺) were mixed and injected intracerebrally in immunodeficient mice. TagRFP⁺/EGFP⁺ ratios were calculated using fluorescent images. A) For E98 this resulted 3-4 weeks later in compact (top panel) and diffuse infiltrative (bottom panel) tumor areas. Representative areas, immunohistochemically stained for TagRFP or EGFP and haematoxylin-counterstained, of one out of three animals are shown. B) E434 glioma tumor-bearing mice were processed 9 weeks post-injection. Representative pictures of one out of two animals are shown. For E434 a 50% transduction efficiency after two consecutive transduction rounds was achieved resulting in also non-transduced cells being injected. C) Quantification of TagRFP⁺/EGFP⁺ ratios in E98 xenografts, as determined for five different tumor areas per animal, averaged and compared to the ratio pre-injection. Error bar represents SD. One-sample Student's t-test yielded p<0.01 (**). D) Quantification of TagRFP⁺/EGFP⁺ ratios in E434 xenografts and pre-injection mixture. Error bar indicates SD.