Figure 2
MDA-MB-231 and MCF-7 breast cancer cell migration was inhibited by exposure to SMRwt exosomes and direct treatment with SMRwt peptide. (A) PEG-SMRwt-CLU exosomes significantly inhibited migration of MDA-MB-231 and MCF-7 breast cancer cells, whereas tumor exosomes significantly promoted migration in these cell lines. Breast cancer cells were treated with either 6 × 107 normal exosomes, tumor exosomes or SMRwt exosomes for 24 h and seeded in a transwell membrane insert. Migrated breast cancer cells were viewed underneath an inverted microscope. *p-value < 0.05, **p-value < 0.008, ***p-value = 0.0001, ****p-value < 0.0001. (B) Direct treatment of MCF-7 and MDA-MB-231 breast cancer cells with SMRwt peptide significantly inhibited migration in the transwell wound healing assay. Breast cancer cells were cultured for 24 h and then treated with IC50 0.56 µM (for MDA-MB-231), 1.12 µM (for MCF-7) SMRwt peptide, or 1 µM MKT-077 (control). Following 24 h, the wound healing assay was performed. **p-value = 0.001, ***p-value = 0.0004, ****p-value < 0.0001. (C) MDA-MB-231 and MCF-7 breast cancer cell migration was significantly blocked by all SMRwt peptides, while no effect was observed on the non-tumorigenic MCF-10A cells. Breast cancer cells were treated with IC50 0.56 µM (for MDA-MB-231), 1.12 µM (for MCF-7) SMRwt peptide or 3 µM Latrunculin A (control) for 16 h, and the Cell Migration Assay was performed (Calbiochem manual). Relative fluorescence unit of migration was determined at an excitation wavelength of 485 nm and an emission wavelength of 515 nm. *p-value < 0.05, ***p-value = 0.0001, ****p-value < 0.0001. (D) Breast cancer cell migration through an HUVEC monolayer was inhibited by the SMRwt peptides in a Cytoselect Tumor Transendothelial Migration Assay. Migration only at 15.75% and 15.55% following treatment with PEG-SMRwt-CLU of MDA-MB-231 and MCF-7 breast cancer cells, respectively.
