Upregulating Apoptotic Signaling in Neurofibromatosis

Abstract

Abstract : The NF1 that is highly expressed in developing neural cells and loss-of-function mutations in NF1 gene results in deregulation of Ras signaling which contributes to cancer development. We reported that hyperactive Ras could induce apoptosis after inhibiting PKC which was not harmful to normal, cells. To define the role of PKC isoforms, we identified the sequences of shRNAs targeting each PKC isoform. With the aid of PKC inhibitor and shRNAs, we successfully define that the concurrent suppression of PKC alpha/bete lethally interacts with hyperactive Ras in NF1 deficient cells. We also cloned and inserted NF1 effector domain gene into an expression vector tagged with flag and introduced it into NF1 deficient cells that became less sensitive to loss of PKC. Various Ras loop mutant genes were introduced into NF1 deficient cells. Subsequently, the experiments using the mutants and inhibitors demonstrate the involvement of PI3K/Akt and JNK, as Ras downstream effectors, in transmitting the apoptotic signaling. The data that generated through the funding period reached the aims proposed in this grant application and indicate the feasibility of our hypothesis. Now, the completion of the project gives a comprehensive understanding of the synthetic lethal interaction between aberrant Ras in NF1 deficient cells and loss of PKC. However, to elucidate the mechanisms of this synthetic lethality requests further and thorough investigation.