Abstract B45: A search for ideal siRNA targets involved in pathway cross-talks for combinational silencing in human cancer cells

The heterogeneity in the pathways involved in enhanced cell proliferation and survival mechanisms, as well as the mechanisms playing a major role in development of drug resistance, is an important obstacle in cancer treatment. Signaling axes such as PI3K-AKT, Ras-Raf, MEK-ERK, and JAK-STAT pathways have not only been established as major processes involved in enhanced proliferation and activation of the transcription of multiple anti-apoptosis proteins, but are also shown to be interconnected in forming a vast intracellular signaling network. RNA interference, and more specifically, small interfering RNA (siRNA), is a post-transcriptional down-regulation of the expression of a specific protein, and has been studied extensively in the last decade as not only an investigational tool, but also as a therapeutic approach especially in cancer treatment. In the present study, we undertook a systematic approach to simultaneous silencing of two proteins involved in intracellular signaling network in order to inhibit more than one pathway involved in proliferation and survival of cancer cells. After carefully selecting the proteins with pivotal roles in cell survival through diverse pathways, we studied silencing each protein individually and in all possible dual combinations, and evaluated the cell response as the mRNA level of the selected proteins as well as the viable cell number. Our studies reveled that silencing JAK2, STAT3, and JUN have a significant effect on the expression level of anti-apoptotic proteins, e.g., Mcl-1 and survivin, and could negatively impact the survival of MDA435 cells. These results indicate a promising potential for combinational siRNA silencing as an effective anticancer strategy. Citation Format: Hamidreza Montazeri Aliabadi, Parvin Mahdipoor, Hasan Uludag. A search for ideal siRNA targets involved in pathway cross-talks for combinational silencing in human cancer cells. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr B45.