Begoña Alburquerque González¹, Silvia Montoro García², ÁNGEL BERNABÉ GARCÍA³, MANUEL BERNABE GARCIA⁴, Fernando Feliciano López Calderón⁵, Javier Ruiz Sanz⁶, Irene Luque Fernández⁶, Horracio Pérez Sánchez⁷, FRANCISCO JOSE NICOLAS VILLAESCUSA⁸, MARIA LUISA CAYUELA FUENTES⁹, Pablo CONESA ZAMORA¹⁰

(1) Universidad Católica San Antonio de Murcia (UCAM). Grupo IMIB: Patología Molecular y Farmacogenética, 30003, España (Región de Murcia)
(2) Universidad Católica de Murcia, 30170, España (Región de Murcia)
(3) CARDIOLOGIA CLINICA Y EXPERIMENTAL, IMIB, España
(4)
(5) Universidad Católica San Antonio de Murcia, 30204, España (Región de Murcia)
(6) Departamento de Química-Física. Universidad de Granada, 18010, España (Andalucía)
(7) Grupo de Bioinformática estructural. Universidad Católica de Murcia, 30170, España (Región de Murcia)
(8) TRASPLANTE HEMATOPOYÉTICO / TERAPIA CELULAR, IMIB, España
(9) CIRUGÍA DIGESTIVA, ENDOCRINA Y TRASPLANTE DE ÓRGANOS ABDOMINALES, IMIB, España
(10) PATOLOGÍA MOLECULAR Y FARMACOGENÉTICA, IMIB, España

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. Serrated adenocarcinoma (SAC) has been recently recognized as a new subtype of CRC. Consistent with previous evidences, our group identified Fascin1 as a protein directly related to the invasiveness of tumor cells, overexpressed and positively correlated with worse survival in various carcinomas, including SAC. Therefore, Fascin1 has emerged as an ideal target for cancer treatment and the discovery of Fascin1 blockers deserves further research.

An inhibitor of human immunodeficiency virus-1 (HIV-1) integrase (RX3) has been traditionally used to treat HIV/acquired immunodeficiency syndrome. The present study performed an in silico search of potential Fascin1 inhibitors finding RX3 as a potential Fascin1 inhibitor candidate. Firstly, virtual screening techniques, thermofluor and fluorescence titration assays were carried out in order to confirm Fascin1 ligands .Secondly, the effect of RX3 on Fascin1 was assessed by immunofluorescence, transmission electron microscopy (TEM) and migration assays on distinct human colorectal adenocarcinoma cell lines (HCT 116 and DLD-1). We also evaluated the chemotherapeutic potential of RX3 in vivo using zebra fish model.

Interestingly, the protrusion of lamellipodia in high-expressed Fascin1 cells (HCT 116) was notoriously abolished in the presence of the drug (Figure 1A) and TEM confirmed the disorganization of the actin structure compared to control conditions (Figure 1B). Following the addition of the potential Fascin1-blocker, migration of colorectal cancer cell lines was significantly inhibited. These preliminary findings were consistent with in vivo assays; the invasive capacity of colorectal tumor cells was notably impaired in the presence of RX3 without undesirable cytotoxic effects (Figure 2).

In conclusion, the current data show the in vitro efficacy of this drug in human colorectal cancer cells. Besides, the great therapeutic potential of RX3 for the treatment of Fascin1-overexpressing tumors is also demonstrated by the use of a zebra fish model with xenograft tumor implants. Although relatively few tumors are tractable by approved agents, this study highlights the necessity of repurposing drugs for clinical investigation.