(193ag) Screening of Natural Osmolytes for Inhibiting Cancer Causing p53 Hot Spot Mutant Peptides Aggregation

The p53 protein mutation is thought to be responsible for about fifty percent of all the cancers. When the p53 gene is mutated, the protein misfolds and aggregates, resulting in an inactive form of the protein, leading to abnormal cells to grow in an exponential manner [1]. Several studies show that the mutant p53 aggregation is observed in tumor tissue samples, biopsies, as well as in several cancer cell lines indicating the correlation between aggregation and tumor growth [2]. The studies further report that the aggregated mutant p53 proteins, loses their functionality. Hence, development of novel drug candidates that target the p53 mutant aggregations could aid in new directions in treating cancer. Here in this study we focus on the inhibitory effects of natural osmolytes on an aggregation prone 8 amino acid p53 conserved peptide PHITIITL, and hot sopt mutant peptides QPPHITIITL, WPPHITIITL in vitro. We are screening cationic, anionic, zwitterionic, and neutral osmolyte molecules to identify potential inhibitory candidates.

Experimental section:

The aggregation kinetics is studied by, Thioflavin T (ThT) binding assay, dynamic light scattering (DLS), turbidity, circular dichroism (CD), transmission electron microscopy (TEM), and atomic force microscopy (AFM).

Preliminary results:

Initial experiments show that osmolytes in micromolar to few millimolar concentrations significantly inhibits p53 conserved, and mutant peptides aggregation in vitro, and could be promising candidates for p53 mutant/misfolded protein aggregation associated cancer.

References:

1. Silva, J. L., De Moura Gallo, C. V., Costa, D. C. & Rangel, L. P. (2014) Prion-like aggregation of mutant p53 in cancer, Trends in biochemical sciences. 39, 260-7.

2. Soragni, A., Janzen, D. M., Johnson, L. M., Lindgren, A. G., Thai-Quynh Nguyen, A., Tiourin, E., Soriaga, A. B., Lu, J., Jiang, L., Faull, K. F., Pellegrini, M., Memarzadeh, S. & Eisenberg, D. S. (2016) A Designed Inhibitor of p53 Aggregation Rescues p53 Tumor Suppression in Ovarian Carcinomas, Cancer Cell. 29, 90-103.