A photo of Nicolas Nassar.

Member, Division of Experimental Hematology & Cancer Biology

Associate Professor, UC Department of Pediatrics



Biography & Affiliation


The major focus of our laboratory is to understand the regulation and signaling of the GTP-binding protein Ras and other Ras-like GTPases and to find small molecules that inhibit their activity in human cancers. Signaling by Ras-like GTPases is key to almost every cellular process and Ras is among the most mutated genes in human cancer. Despite this, a small molecule specifically targeting Ras activity has yet to enter clinical trials. Our research efforts encompass several methodologies, including protein crystallography, biophysical and biochemical studies, cellular functional assays, and ultimately, high throughput screenings of chemical libraries of small compounds that bind to and modulate GTPase signaling in cell line models.

We have identified several compounds that bind in vitro to Ras, inhibit cell proliferation of lung and other Ras-transformed cell lines, and decrease the activation of Erk-1/-2 and PI3K/AKT. Several ongoing questions stem from this finding: (i) we want to establish the mechanism of action(s) of these compounds. What gene or cellular process do they activate or silence downstream of Ras? Do they bind to Ras in cells and how specific is their binding? (ii) We are in the process of translating our findings to several disease models where Ras is hyperactivated, including both solid tumors such as lung adenocarcinomas, and MPNSTs and leukemias such as B-ALL.

We are also interested in the structure/function relationship of the multidomain protein tyrosine phosphatase (PTP) UBASH3B/Sts-1. Sts-1 was shown to be a target in triple negative breast cancer (TNBC). Our research is geared towards identifying small molecule inhibitors of the phosphatase activity of Sts-1. We have identified one such compound that inhibits the phosphatase activity of Sts-1 in vitro, decreases TNBC cell proliferation and decreases overall levels of phosphorylated proteins. We are currently testing structural analogs of our lead compound to further improve its potency.

Academic Affiliation

Associate Professor, UC Department of Pediatrics


Experimental Hematology and Cancer Biology, Cancer and Blood Diseases

Science Blog


PhD: University Joseph Fourier, Grenoble,France, 1992.

Postdoc: Max Plank Institut, Dortmund, Germany, 1996.

Research Associate: Cornell University, Ithaca, NY, 2000.

Assistant Professor: Stony Brook University, NY, 2006.

Research Assistant Professor: Stony Brook University, Stony Brook, NY, 2010.


Selected Publication

IODVA1, a guanidinobenzimidazole derivative, targets Rac activity and Ras-driven cancer models. Gasilina, A; Premnauth, G; Gurjar, P; Biesiada, J; Hegde, S; Milewski, D; Ma, G; Kalin, TV; Merino, E; Meller, J; et al. PLoS ONE. 2020; 15:e0229801-e0229801.

Rational identification of a Cdc42 inhibitor presents a new regimen for long-term hematopoietic stem cell mobilization. Liu, W; Du, W; Shang, X; Wang, L; Evelyn, C; Florian, MC; Ryan, MA; Rayes, A; Zhao, X; Setchell, K; et al. Leukemia. 2019; 33:749-761.

Real-time genomic profiling of histiocytoses identifies early-kinase domain BRAF alterations while improving treatment outcomes. Lee, LH; Gasilina, A; Roychoudhury, J; McCormack, FX; Pressey, J; Grimley, MS; Lorsbach, R; Ali, S; Bailey, M; Stephens, P; et al. JCI insight. 2017; 2.

UBASH3B/Sts-1-CBL axis regulates myeloid proliferation in human preleukemia induced by AML1-ETO. Goyama, S; Schibler, J; Gasilina, A; Shrestha, M; Lin, S; Link, KA; Chen, J; Whitman, SP; Bloomfield, CD; Nicolet, D; et al. Leukemia. 2016; 30:728-739.

Breast cancer-associated missense mutants of the PALB2 WD40 domain, which directly binds RAD51C, RAD51 and BRCA2, disrupt DNA repair. Park, J; Singh, TR; Nassar, N; Zhang, F; Freund, M; Hanenberg, H; Meetei, AR; Andreassen, PR. Oncogene: Including Oncogene Reviews. 2014; 33:4803-4812.