Identification of novel chemotherapies targeting mitochondrial‐cell communication.

Ovarian cancer (OC) is the most lethal gynecological malignancy. OC mortality is associated with a high rate of recurrence (~80%). Recurrent OC is typified by treatment resistant cells; thus, conventional therapies are often ineffective. Therefore, it is imperative to find novel drugs to eliminate recurrent OC cells. We propose that targeting mitochondrial‐cell communication in recurrent OC will increase chemotherapeutic efficacy. Preliminary data demonstrate that increasing the concentration of the mitochondrial scaffold protein Sab sensitizes OC cells to paclitaxel by inducing apoptotic priming. These studies suggest that increasing Sab levels in OC will induce a pre‐apoptotic state and sensitize the tumor cells to conventional therapies, thus rendering resistant OC cells sensitive. We developed a high throughput assay to screen a scaffold ranking and positional scanning library in order to identify novel chemicals that increase Sab expression in SK‐OV‐3 cells. An In‐Cell Western (ICW) assay was used to detect Sab levels, and this assay was optimized for screening (z‐score of 0.81). The Sab ICW was co‐stained with the TO‐PRO‐3 DNA stain for normalization and to assess viability. We screened 50 scaffolds in SK‐OV‐3 cells. Scaffolds selected for further evaluation increased Sab expression greater than 30% and demonstrated minimal toxicity. Using this method we identified six candidate scaffolds. Of these, N‐Methyl‐1,4,5‐tri‐substituted‐2,3‐diketopiperazines were considered to be the best candidates. We predict that this approach will identify novel chemotherapeutic drugs that will improve OC treatment and mortality.