PD43-01: Pevonedistat Sensitizes Renal Medullary Carcinoma Cells to Carboplatin by Disrupting DNA Damage Repair Mechanisms

Daniel Shapiro*, Madison, WI, Niki Millward Zacharias, Durga Tripathi, Jean-Philippe Bertocchio, Melinda Soeung, Rong He, Jianjun Gao, Priya Rao, Truong Lam, Luigi Perelli, Alessandro Carugo, Timothy Heffernan, Cheryl Walker, Giannicola Genovese, Nizar Tannir, Christopher Wood, Jose Karam, Pavlos Msaouel, Houston, TX

Introduction: Renal medullary carcinoma (RMC) is an aggressive SMARCB1(-) cancer with median survival of only 13 months.  Current management consists of carboplatin and paclitaxel, however new therapies are needed.  We previously identified proteotoxic and replication stress as RMC cellular hallmarks. The neddylation pathway protects cells from proteotoxic and replication stress. We hypothesized that neddylation inhibition with pevonedistat will synergistically enhance carboplatin antitumor effects in RMC.

Methods: We evaluated the IC50 concentrations of the neddylation activating enzyme inhibitor pevonedistat in vitro using platinum-naïve RMC2C and platinum experienced RMC219 cell lines and 2 other SMARCB1(-) cell lines.  To determine synergy, growth inhibition was measured after treating with varying concentrations of pevonedistat (0-0.5µM) and carboplatin (0-80µM).  Bliss synergy scores were calculated using the SynergyFinder app. Scores >10 indicate synergy between pevonedistat and carboplatin.  We evaluated proteins involved in DNA damage repair using western blot.  Lastly, we evaluated tumor inhibition combining pevonedistat with carboplatin + paclitaxel using 2 patient derived xenograft models (RMC2X and RMC32X).

Results: The 2 RMC cell lines demonstrated IC50 concentrations below the maximum tolerated dose in humans (Fig 1A). When combined with carboplatin, pevonedistat demonstrated a significant synergistic effect with Bliss scores >10 in both RMC2C (score 22.91) and RMC219 (score 15.15) cell lines (Fig 1B).  Pevonedistat caused down regulation of nucleotide excision repair (NER) pathway proteins including FANCD2 and activated ATR (p-ATR), and increased expression of p53 (known to suppress FANCD2).  Pevonedistat with carboplatin suppressed p-CDK1(Tyr-15), which inhibits cell cycle progression (Fig 1C).  Lastly, pevonedistat with carboplatin+paclitaxel significantly inhibited PDX tumor growth (Fig 1D).

Conclusions: Pevonedistat synergizes with carboplatin to inhibit cell and tumor growth, likely through NER pathway inhibition.  This pathway repairs carboplatin-induced DNA interstrand crosslinks.  This study supports developing a clinical trial combining pevonedistat with platinum-based chemotherapy for RMC.

Source of Funding: DOD Concept Award (W81XWH1810570)