Researchers at Washington’s Georgetown University have used a gene editing approach to correct Phosphatase and Tensin homolog (PTEN) gene mutations in human glioblastoma cell lines.
PTEN is a well-known tumor suppressor gene; mutations of which are associated with both familial and sporadic cancers. Earlier studies looking at 12 different cancer types found PTEN to be the third most commonly mutated gene after TP53 and PIK3CA. Additionally, down-regulation of PTEN is closely linked to the activation of Akt signaling which exerts numerous cellular effects including cell survival, cell cycle regulation, glycogen synthesis, and cell growth – contributing to the proliferation of tumor cells.
In glioblastoma multiforme (GBM), an aggressive brain cancer, approximately 60% of cases present alterations in the PTEN or PI3K genes. Researchers therefore chose to target PTEN mutations via human somatic cell gene targeting in two GBM cell lines (42MGBA and T98G). An adeno-associated virus (AAV) vector designed to correct tumor-derived PTEN mutations in exon 2 was used to transfect both the cell lines.
The results published in PloS One confirmed successful correction of the PTEN mutation in both cells lines. This was validated by the expression of endogenous wild-type PTEN in the 42MGBA cells; and PTEN mRNA expression in T98G cells. Further tests to assess the biological effects of PTEN correction revealed attenuated cellular proliferation of these cells. In addition, the study also showed that the effects of PTEN correction was mediated either through Akt signaling (in 42MGBA cells) or independant of Akt signaling (in T98G cells).
Researchers hope that this work will be an initial step towards the discovery and validation of novel therapeutics targeting the PTEN pathway.
Source: Correction of PTEN mutations in glioblastoma cell lines via AAV-mediated gene editing.
Hill V, Jung-Sik K, David J, Waldman T. PLoS One. May 2017. DOI