The impact of novel compound 2'-hydroxyflavanone on proteomic networks of VHL-mutant renal cell carcinoma.

Abstract

e13557 Background: Von Hippel-Lindau (VHL) tumor suppressor is a major genetic factor that determines hypoxic acclimatization and response to therapy in renal cell carcinoma (RCC). Our initial studies revealed that 2'-Hydroxyflavanone (2HF) effectively inhibits the survival of VHL-mutant RCC. Hence, we performed proteomic analyses to study the signaling networks of clinical significance that are regulated by 2HF in VHL-mutant RCC. Methods: The 786-O cells, an established cell line from a male Caucasian patient, were provided by William Kaelin Jr., MD, Harvard Medical School, Boston, MA. The cells were cultured either in the presence or absence of 50 μM 2HF for 48 h in RPMI medium at 37°C in 5% CO2 and lysed in a buffer containing 6M urea. The lysate (200 µg of protein) was reduced, alkylated and digested with trypsin. Tryptic digests were desalted using a C-18 cartridge (Waters, USA) and subjected to liquid chromatography–tandem mass spectrometry (LC-MS/MS) analyses on linear ion trap–Fourier transform ion cyclotron resonance tandem mass spectrometer (LTQ-FT, Thermo) coupled to an Eksigent nano-LC system. MS/MS spectra were searched against human protein sequence database using Mascot (Matrix Science), and protein identifications were validated by Scaffold (version 3.0, Proteome Software). Quantifications were performed by extracted peptide intensities (Progenesis LC-MS, Nonlinear Dynamics). Results: 2HF treatment lead to up-regulation of 21 proteins including protein disulfide-isomerase A4 and macrophage migration inhibition factor. 2HF treatment lead to down-regulation of 23 proteins including vimentin, HSP90AB1, 14-3-3 gamma and glutaminase. The network analyses revealed that the identified proteins form critical nodes of regulation of vital tumor proteins like MAP3K14, ERK1/2, Myc and P53. Conclusions: Proteomic analyses of 2HF treated VHL-mutant RCC revealed a striking regulation of proteins of importance in RCC survival, invasion and metastases. The critical nodes of regulation as identified by the network analyses could facilitate further studies on the development of network targeting therapies using 2HF and other anti-cancer compounds for the effective management of VHL-mutant RCC.