Abstract 2893: Transmembrane Chloride Intracellular Channel 1 (tmCLIC1) protein as a potential target for colorectal cancer metastasis

Abstract

Abstract Colorectal cancer (CRC) is the third most common tumor worldwide and the fourth cause of cancer-related death. The presence of distal metastasis at the time of the first diagnosis represents a worst prognosis factor for patients' long-term survival. Therefore, finding new targets to arrest the metastatic process is a main challenge for successful CRC therapy. Our laboratory focused its attention on the Chloride Intracellular Channel 1 (CLIC1), a metamorphic protein able to switch from a cytoplasmic to a transmembrane form associated to ion channel activity. Previous experiments demonstrated that transmembrane CLIC1 (tmCLIC1) functional activity is negligible in normal colon cells, while increases proportionally to CRC cells' aggressiveness. Moreover, we also revealed that tmCLIC1 supports CRC cells abnormal proliferation rate. Here, we show that tmCLIC1 pharmacological inhibition or its stable knock-down by gene silencing led to a significative reduction of CRC cells migrative and invasive potential, in vitro. To further confirm our hypothesis, we assessed in CLIC1 knock-down cells the downregulation of metalloproteinase-7 (MMP-7) protein and p38 mitogen-activated protein kinase (MAPK) signaling, both involved in migration and metastatic processes. Moreover, by injecting subcutaneously transfected cell lines in nude mice, we demonstrate that CLIC1 knock-down impairs tumor growth and limits cancer cells dissemination to lung. Our results suggest a role for tmCLIC1 in promoting CRC metastasis, making this protein a promising pharmacological target to arrest or slow-down CRC metastasis development. Moreover, thanks to its functional expression exclusively associated with malignant progression, tmCLIC1 could allow to limit side effects on healthy cell population. Citation Format: Francesca Cianci, Valentina Carlini, Ivan Verduci, Matteo Ranucci, Michele Mazzanti. Transmembrane Chloride Intracellular Channel 1 (tmCLIC1) protein as a potential target for colorectal cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2893.