Abstract B24: Met and VDAC1 as target for breast cancer therapy
Authors: Namir Guy , Shoshan-Barmatz Varda , Tsarfaty Ilan 
Published: August 2018

During the past decade, considerable efforts have been devoted to the identification of agents that selectively kill neoplastic breast cancer cells based on their signaling and metabolic alterations. We hypothesis that combination tyrosine kinase and metabolic inhibitors are potential novel therapies for breast cancer.

Aberrant signaling through Met-tyrosine kinase receptor and its ligand hepatocyte growth factor/scatter factor (HGF/SF) has been shown to play a critical role in development of tumors and metastasis in a variety of cancers, including breast cancer. We have previously shown that HGF/SF-induced Met-activation leads to diverse metabolic alteration in the tumor. Activation of Met signaling increases glycolytic flux into lactate and increases glycolysis, oxidative phosporylation, oxygen consumption, and tumor blood volume.

The voltage-dependent anion channel 1 (VDAC1), located in the mitochondrial outer membrane, functions as gatekeeper for the entry and exit of mitochondrial metabolites, thereby controlling crosstalk between mitochondria and the rest of the cell. VDAC1 is also a key player in mitochondria-mediated apoptosis. Thus, in addition to regulating the metabolic and energetic functions of mitochondria, VDAC1 appears to act as a convergence point for a variety of cell survival and cell death signals, mediated by its association with various ligands and proteins. Shoshan-Barmatz’s lab developed the retro-Tf-D-LP4 peptide, a cell-penetrating VDAC1-based peptide that acts by inducing apoptosis and impairment of cell energy and metabolism. To study the possible therapeutic effect of Met inhibition and alteration of VDAC1 combined therapy on breast tumor cells, we evaluated cell proliferation and motility in BC cells. Using our newly developed single-cell 35 parameters morphokinetic analysis infrastructure, we demonstrate that after 24 hours, the peptide decreased all cell lines velocity (5µM; MDMDA-MB-231_velocity=8.2%, p=0.024. 15µM; MDMDA-MB-231_velocity=62.4%, p&lt;0.001). The peptide in combination with Met inhibitor further decreased cell velocity and acceleration (MDMDA-MB-231_Velocity=85.9%, p&lt;0.001; MDMDA-MB-231_Acceleration=76%, p&lt;0.001). The combined treatment increased cell coordination but abrogated the back-propagating wave. The morphologic effect of the treatment was dependent on the cell line. Cluster analysis of morphokinetic parameters demonstrated that untreated or low doses of treatment MDA-MB-231 and HB2 are clustered together; MCF7 and T47D have slower motility parameters. Upon high-dose combined treatment MDA-MB-231 cells change are clustered with slow-velocity T47D and MCF7. Combined Met inhibition and VDAC1 alteration dramatically reduced cell motility and increased coordinated motility. In vitro experiments show a slight inhibitory effect of VDAC1 on MDA-MB-231 cell proliferation. However, in vivo experiments demonstrate an inhibitory effect on tumor growth. These results indicate that the combined therapy can reduce cell motility and metastasis in triple-negative breast cancer tumors.

Citation Format: Guy Namir, Varda Shoshan-Barmatz, Ilan Tsarfaty. Met and VDAC1 as target for breast cancer therapy [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B24.