AAV DJ-Cre

Glioblastoma (GBM) is a dreaded brain tumor with a particular relationship to the adult subventricular zone (SVZ), which is purported to be involved in the development, progression, and recurrence of the disease. Here, researchers present a novel strategy to detect and track xenografted GBM cells located in the SVZ based on an intracerebroventricular (icv) recombinant adeno-associated virus (AAV)-mediated color conversion approach. After comparing the efficiency of different rAAV serotypes, they confirmed that in vitro transduction of GSC-LRLG with rAAV-Cre induced a change from red to green fluorescence. At the same time, rAAV transduction was restricted to the lateral ventricle wall. Therefore, researchers applied this conversion approach in 2 patient-derived orthotopic GSC xenograft models and showed that the icv injection of an rAAV-DJ-Cre after GSC-LRLG tumor implantation triggered the conversion of red GSCs to green, in the periventricular region. Green GSCs were also found at distant sites, including the migratory tract and tumor core.

The researchers tested the ability of rAAV-DJ-Cre to promote red-to-green switching in GSC intrastriatal xenografts over different time frames. At 6 weeks, T033-LRLG cells formed a large invasive tumor that invaded the right lateral ventricles (LV) and the left LV lateral wall through the CC. At week 5 post-engraftment, rAAV-DJ-Cre was injected intracerebroventricularly into the left LV (Figure 1A). One week later, the mice were sacrificed and the brains were collected. Immunostaining showed dsRed+ T033-LRLG cells scattered in the right hemisphere as well as the right and left LV. eGFP+ cells were detected not only near the left LV, but also near the right LV and within the tumor core (Figure 1B-C). These eGFP +  cells were SOX2⁺ and Ki67⁺, indicating a sustained proliferation potential.

Figure 1. rAAV-DJ-Cre icv injection induces red-to-green conversion of T033-LRLG that reached the subventricular zone (SVZ) in an orthotopic xenograft model. (Lombard A, et al., 2024)