Abstract 1233: In vitro and in vivo pharmacological study of EB-3D: a novel choline kinase inhibitor for breast cancer treatment
Authors: Mariotto Elena , Bortolozzi Roberta , Ronca Roberto , López-Cara Luisa C. , Accordi Benedetta , Serafin Valentina , Basso Giuseppe , Viola Giampietro 
Published: July 2016

Choline kinase (ChoK) catalyzes the phosphorylation of choline to phosphocholine (PCho) in the first step of the Kennedy pathway for phosphatidylcholine (PtdCho) byosyntesis. PtdCho is the most abundant phospholipid in eukaryotic cell membrane and plays a crucial role for cell division and lipid second messengers production. In mammalian cells, only the ChoKα isoform is fundamental in sustaining PtdCho synthesis, indeed ChoKβ alone cannot compensate this activity.

A large number of studies have shown that ChoKα is overexpressed and hyperactivated in many cancers and that correlates not only with increased cancer cell proliferation but also with malignancy, making it a potential prognostic marker. The cholinic phenotype, characterized by increased total choline-containing compound (tCho) and ChoKα upregulation renders therefore ChoKα an attractive new therapeutic target. Indeed, the feasibility of ChoKα inhibition as antitumoral therapy is being pursued through the development of chemical inhibitors of its enzymatic activity.

For this reason we evaluated both in vitro and in vivo the activity of EB-3D (1,1’-(((ethane-1,2-diylbis(oxy))bis(4,1-phenylene))bis(methylene))bis(4-(dimethylamino) pyridinium) bromide), a new choline kinase inhibitor endowed with high antiproliferative activity in two human breast cancer cell lines, MCF-7 and MDA-MB-231. EB-3D treatment induced a strong decrease in cell proliferation due to G1/G0 arrest of the cell cycle in a concentration-dependent manner in both tested cell lines, whereas only a slight increase in apoptotic cells was observed. In addition EB-3D strongly synergized with drugs commonly used in protocols for breast cancer.

Reverse-phase protein array (RPPA) data revealed the activation of AMPK and the dephosporylation of mTORC1 downstream targets such as 4E-BP1(S65), p70S6K(T389) and RPS6(S235/236), suggesting that ChoKα inhibition may affect protein synthesis.

To further examine the antitumorigenic potential of EB-3D in vivo, a syngeneic orthotopical EO771-C57BL/6 mouse model of breast cancer was used. Preliminary results indicated that the compound significantly reduced the tumor size, with no apparent sign of toxicity.

The evaluation of EB-3D as in vivo anti-metastatic adjuvant is ongoing, since cell migration and cell invasion ability of the highly metastatic MDA-MB-231 cell line was impaired after in vitro treatment.

Taken together our results suggest that EB-3D have a potent cytostatic effect and it could be a promising new anticancer agent, worthy of further development.

Citation Format: Elena Mariotto, Roberta Bortolozzi, Roberto Ronca, Luisa C. López-Cara, Benedetta Accordi, Valentina Serafin, Giuseppe Basso, Giampietro Viola. In vitro and in vivo pharmacological study of EB-3D: a novel choline kinase inhibitor for breast cancer treatment. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1233.