ALCAM (Activated Leukocyte Cell Adhesion Molecule) is associated with HGF/MET signalling pathway in different subtypes of breast cancer

Abstract Introduction. ALCAM (Activated Leukocyte Cell Adhesion Molecule), also known as CD166, is a cell adhesion molecule which belongs to the immunoglobulin superfamily and is widely expressed in various human tissues. It has been demonstrated that ALCAM plays an important role in the progression of malignant diseases and tumour metastasis in multiple cancer types including breast cancer. However, the molecular mechanism of ALCAM and cancer progression is currently unclear. The present study performed protein array analyses using ALCAM genetically manipulated cell models to select potential protein partners of ALCAM. The study focused on MET (Hepatocyte Growth Factor (HGF) Receptor), a prominent ALCAM interacting protein kinase and a protooncogene contributing to cancer progression and spread. Method. Human breast cancer cell lines MCF-7 and MDA-MB-231 were selected to create ALCAM knockdown cell models. A range of other breast cancer cell line with differing hormone receptor status were also used. Protein samples of transfected cells were used to perform Kinexus protein kinase microarray analysis. The protein interaction between ALCAM and other prospective protein kinases including MET was verified by the method of immunoprecipitation. Additionally, the ALCAM knockdown model was also assessed for the impact of ALCAM and HGF/MET on the biological functions by Electric Cell-substrate Impedance Sensing (ECIS). Results. MCF-7 and MDA MB-231 cells both were strongly expressed ALCAM. Cells models with ALCAM knocking down were successfully created by way of anti-ALCAM shRNA. We have shown on the protein kinase microarray analysis that the hepatocyte growth factor (HGF) receptor, MET was one of the kinases significantly affected following ALCAM knocking down. It was also found that the alteration of protein interaction between the MET protein kinase and ALCAM protein showed an opposite pattern between ER positive and ER negative ALCAM knocking down cells. This protein interaction was observed by immunoprecipitation in MDA-MB-361 and MDA-MB-231 cell lines, but not in MCF-7 cells. The biological analyses using the ECIS technologies showed that MET kinase inhibitors and exogenous recombinant HGF affected the ALCAM-mediated cell adhesion in different breast cancer subtypes. Conclusion. ALCAM is associated with HGF/MET signalling and the interaction between ALCAM and MET is different amongst subtypes of breast cancer which have different hormone receptor status. Citation Format: Yiming Yang, Andrew J. Sanders, Wen G. Jiang. ALCAM (Activated Leukocyte Cell Adhesion Molecule) is associated with HGF/MET signalling pathway in different subtypes of breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-12-01.