The secretome of non-tumorigenic mammary cells MCF-10A elicits DNA damage in MCF-7 and MDA-MB-231 breast cancer cells

Non-tumorigenic epithelial breast cells and ionizing radiation cooperate in the enhancement of mesenchymal traits in tumorigenic breast cancer cells

AIMS

Radioresistance and recurrences are crucial hindrances in cancer radiotherapy. Fractionated irradiation can elicit a mesenchymal phenotype in irradiated surviving cells and a deep connection exists between epithelial mesenchymal transition, radioresistance, and metastasis. The aim of this study was to analyze the effect of the secretoma of irradiated non-tumorigenic mammary epithelial cells on surviving irradiated breast tumor cells regarding the gain of mesenchymal traits and migratory ability.

MAIN METHODS

MDA-MB-231 and MCF-7 breast cancer cells, irradiated or not, were incubated with conditioned media from MCF-10A non-tumorigenic epithelial breast cells, irradiated or not. After five days, we evaluated the expression and localization of epithelial and mesenchymal markers (by western blot and indirect immunofluorescence), cell migration (using transwells) and metalloproteinases activity (by zymography). We also assessed TGF-β1 content in conditioned media by immunoblot, and the effect of A83-01 (a selective inhibitor of TGF-β receptor I) and PP2 (a Src-family tyrosine kinase inhibitor) on nuclear Slug and cell migration.

KEY FINDINGS

Conditioned media from MCF-10A cells caused phenotypic changes in breast tumor cells with attainment or enhancement of mesenchymal traits mediated at least in part by the activation of the TGF-β type I receptor and a signaling pathway involving Src activation/phosphorylation. The effects were more pronounced mostly in irradiated tumor cells treated with conditioned media from irradiated MCF-10A.

SIGNIFICANCE

Our results suggest that non-tumorigenic epithelial mammary cells included in the irradiation field could affect the response to irradiation of post-surgery residual cancer cells enhancing EMT progression and thus modifying radiotherapy efficacy.

Colorimetric Aptasensor Based on Fe₃O₄-Cu2+ Nanozyme with Intrinsic Peroxidase-Like Activity in the Detection of Breast Cancer Exosomes

Because breast cancer cells such as MCF-7, exhibit vital and developmental signs by exosome secretion, diagnosing them in the blood can provide a good index of the presence of breast cancer. However, accurate and inexpensive detection of exosomes in clinical practice faces challenges. Therefore, in the presents study, an aptasensor based on CD63 aptameriron oxide-copper ion nanozymes (Fe₃O₄-Cu²⁺-NZs) was designed with the ability of the CD63 aptamer to interact with the exosome and the release of the Fe₃O₄-Cu²⁺-NZs for peroxidase-like activity on the tetramethylbenzidine (TMB). After fabrication of CD63 aptamer-Fe₃O₄-Cu²⁺-NZs based on hydrothermal method, their physicochemical properties were investigated with the SEM, TEM, DLS, Zeta, XRD and magnetization. To investigate the interaction of CD63 aptamer-Fe₃O₄-Cu²⁺-NZs with exosomes, the required exosomes were extracted from cultured MCF-7 cells. The performance of CD63 aptamer-Fe₃O₄-Cu²⁺-NZs on TMB degradation in the presence and absence of exosomes was investigated through UV-vis adsorption and ocular observations based on colour changes on laboratory and real samples. The results show that the absence of exosomes significantly inhibited the peroxidase-like activity of CD63 aptamer-Fe₃O₄-Cu²⁺-NZs due to the aptamer coating. Under optimal conditions, the designed CD63 aptamer-Fe₃O₄-Cu²⁺-NZs is capable of detecting exosomes in the range of 1.4 × 10⁴-5.6 × 10⁵ particles/μL with a detection limit of 5.91 × 10³ particles/μL. Also, this method showed a satisfactory outcome in detection of cancer cells in real samples. Overall, this colorimetric aptasensor can be used to diagnose breast cancer cells based on a simple and inexpensive approach.

KIF18B promotes breast cancer cell proliferation, migration and invasion by targeting TRIP13 and activating the Wnt/β‑catenin signaling pathway

Kinesin superfamily member 18B (KIF18B) has previously been reported to be upregulated in breast cancer (BC) and is involved in BC tumorigenesis. Therefore, the present study aimed to investigate the effects and underlying mechanisms of KIF18B in BC. Comprehensive bioinformatics analysis was performed, using data from The Cancer Genome Atlas. KIF18B knockdown and thyroid hormone receptor-interacting protein 13 (TRIP13) overexpression in BC cells were induced via transfection, by using the short hairpin RNA-KIF18B and overexpression-TRIP13 vectors, respectively. Cellular processes, including proliferation, migration and invasion were assessed using colony formation, wound healing and Transwell assays, respectively. mRNA and protein expression levels were determined using reverse transcription-quantitative PCR and western blot analysis, respectively. Protein-protein interactions were determined using co-immunoprecipitation. The results demonstrated that the KIF18B expression levels were upregulated in BC, particularly in triple-negative BC (TNBC) tissues and cell lines. KIF18B knockdown inhibited the proliferation, migration and invasion of HCC-1937 TNBC cells. Furthermore, MMP12 and MMP9 protein expression levels were decreased by KIF18B knockdown. TRIP13 expression was also demonstrated to be upregulated in BC, particularly in TNBC tissues and cell lines. TRIP13 expression levels positively correlated with those of KIF18B in BC tissues and cells, and further analysis verified that TRIP13 and KIF14B were able to directly bind to each other. However, TRIP13 overexpression abolished the effects of KIF18B knockdown on HCC-1937 cells. Furthermore, KIF18B knockdown decreased β-catenin, c-Myc and cyclin D1 protein expression levels; however, TRIP13 overexpression resulted in the recovery of all respective protein expression levels. On the whole, the present study demonstrates that KIF18B promotes BC malignant events, including the proliferation, migration and invasion of TNBC cells. These results indicate that KIF18B may play an oncogenic role in BC by upregulating TRIP13 expression, thereby activating the Wnt/β-catenin signaling pathway.