Targeting LIN28B in DIPG

Background

LIN28B is a key developmental gene that is also involved in many cancers. We and other groups have identified LIN28A and LIN28B activation in pediatric brain tumors, specifically medulloblastoma, atypical teratoid/rhabdoid tumor (AT/RT) and diffuse intrinsic pontine glioma (DIPG). Our laboratory has significant experience targeting LIN28 using short hairpin RNAs (shRNAs). We will use our validated lentiviral short hairpin RNA sequences to knockdown LIN28B in DIPG cells. We know from our preliminary data that LIN28B knockdown in DIPG decreases proliferation and invasion.

We do not know if loss of LIN28B will affect tumorigenicity and we do not have a full understanding of the mechanism by which LIN28B loss affects DIPG. We will determine expression of let7 microRNAs using established Taqman assays. We will measure by qPCR and western blot the expression of known LIN28B downstream effectors such as MYC, NMYC, HMGA2, IGF2, KRAS, and AKT. Many of these genes are altered or aberrantly expressed in DIPG. To determine the effect of LIN28B knockdown on DIPG tumorigenicity, we will inject these cells into the pons of immunodeficient mice. We will perform in vivo imaging and will measure overall survival. We will use pLKO (empty vector) as control.

Project Goal

We hypothesize that LIN28B knockdown mice will have delayed tumor growth and will have extended overall survival. Together these experiments will provide the justification for further exploring targeting LIN28B in DIPG.