The Effect of BCSC-1 and IQGAP1 on the Migration of Breast Cancer Cells and Their Clinical Significance in Invasive Ductal Carcinoma

ZHANG Qingchen^1#, MA Yuan^1#, ZHONG Pei¹, REN Sifan¹, HAO Wei¹, PAN Yi¹, JU Jiyu²*, ZHAO Chunling^1,2*

（¹School of Life Science and Technology, Shandong Second Medical University, Weifang 261053, China; ²Key Laboratory of Immune Microenvironment and Inflammatory Disease Research in Universities of Shandong Province, School of Basic Medical Sciences, Shandong Second Medical University, Weifang 261053, China)

Abstract:

This study aims to investigate the effect of BCSC-1 and IQGAP1 on the migration of breast cancercells and their clinical significance in invasive ductal carcinoma of the breast. The interaction between BCSC-1 and IQGAP1 in breast cancer cell MCF-7 was detected by immunoprecipitation assay. Cell immunofluorescence assay was used to detect the co-localization of BCSC-1 and IQGAP1 in MCF-7 cells. Western blot was used to detect the respective effect of BCSC-1 overexpression and IQGAP1 overexpression on the expression level of IQGAP1 and BCSC-1. Cell scratch assay, cell immunofluorescence assay combined with RNA interference were used to detect the localization of BCSC-1 and IQGAP1 in migrating MCF-7 and MDA-MB-231 cells, as well as their interdependence of localization to the leading edge of membrane. Western blot was used to detect the protein expression of BCSC-1 and IQGAP1 in various breast cancer cells. Immunohistochemical staining was used to detect the expression of BCSC-1 and IQGAP1 in invasive ductal carcinoma of the breast and adjacent tissues, as well as their correlation with the clinical and pathological characteristics of invasive ductal carcinoma of the breast. BCSC-1 interacted with IQGAP1 and co-localized with IQGAP1 in MCF-7 cells; BCSC-1 and IQGAP1 expression did not influence each other. No matter whether MCF-7 cells and MDA-MB-231 cells were in a random migration state or a directional migration state, BCSC-1 was located in the cytoplasm and membrane front of breast cancer cells, co-located with IQGAP1, and their localization to the leading edge of membrane were interdependent; BCSC-1 was downregulated and IQGAP1 was upregulated in a variety of breast cancer cells; BCSC-1 was downregulated (P<0.05), while IQGAP1 was upregulated in invasive ductal carcinoma tissues compared with adjacent tissues (P<0.05). In invasive ductal carcinoma, the low expression of BCSC-1 was related to the histological grade and lymph node metastasis of breast cancer (P<0.05), but not to the status of ER, PR and HER2 (P>0.05), while the high expression of IQGAP1 was related to lymph node metastasis (P<0.05) and HER2 status (P<0.05). The expression of BCSC-1 and IQGAP1 showed a negative correlation (R=–0.416, P<0.05). BCSC-1 and IQGAP1 interact to synergistically regulate the migration of breast cancer cells. They are involved in the development of invasive ductal carcinoma of the breast and are related to its metastasis.

CSTR: 32200.14.cjcb.2025.07.0004