ABSTRACT
Tumor vascular endothelial cells play a pivotal in the tumor microenvironment, influencing the proliferation, invasion, and metastasis of tumor progression. The present study investigated a novel method for inducing the transformation of breast cancer stem cells into endothelial cells, providing a cellular model investigating anti-angiogenic mechanisms in vitro. The breast cancer cell line MCF-7 was used, and the expression of CD133 was initially detected using flow cytometry. CD133+ breast cancer cells were purified using immunomagnetic bead sorting technology, yielding an MCF-7CD133+ subpopulation. The proliferation ability of these cells was assessed using an MTT assay, while their microsphere formation ability was evaluated using a microsphere formation assay. Post-transformation in an optimized endothelial cell culture medium, expression of endothelial cell markers CD31 and CD105 were detected using flow cytometry. Endothelial cell tube formation assays and DiI-labeled acetylated low-density lipoprotein (DiI-Ac-LDL) assays were employed to analyze the endothelial cell function of the MCF-7CD133+ cells. MDM2/CEN12 gene amplification was detected through fluorescence in situ hybridization (FISH). The MCF-7 breast cancer cell line exhibited 1.7±0.3% trace cells expressing the stem cell surface marker CD133. After anti-CD133 immunomagnetic bead sorting, MCF-7CD133+ and MCF-7CD133- subpopulation cells were obtained, with CD133 expression rates of 85.6±2.8 and 0.18±0.08%, respectively. MTT assay results demonstrated that, after 7 days, the proliferation rate of MCF-7CD133+ cells was significantly higher compared with MCF-7CD133- cells. MCF-7CD133+ subpopulation cells displayed strong stem cell characteristics, growing in suspension in serum-free media and forming tumor cell spheres. In contrast, MCF-7CD133- cells failed to form microspheres. After culturing cells in endothelial cell differentiation and maintenance media, the percentage of MCF-7CD133+ cells before and after endothelial cell culture was 0.3±0.16 and 81.4±8.37% for CD31+ cells and 0.2±0.08 and 83.8±7.24% for CD105+ cells, respectively. Vascular-like structure formation and Ac-LDL phagocytosis with red fluorescence in the tube formation assays confirmed endothelial cell function in the MCF-7CD133+ cells. FISH was used to verify MDM2/CEN12 gene amplification in the induced MCF-7CD133+ cells, indicating tumor cell characteristics. The modified endothelial cell transformation medium effectively induced differentiated tumor stem cells to express vascular endothelial cell markers and exhibit endothelial functions, ideal for in vitro anti-angiogenesis research.
ABSTRACT
In this study, a long carbon chain dimer acid is introduced into a nylon 6 structure and is copolymerized with different structural amines to produce amorphous nylon 6 by 4,4'-methylenebis(2-methylcyclohexylamine) (MMCA) in different copolymerization ratios. The effect of different structures and copolymerization ratios on the properties of nylon 6 is determined, along with the thermal properties, crystallinity, water absorption, dynamic mechanical properties, and optical properties. It is found that the melting point and the thermal cracking temperature Td10 of nylon 6 are respectively between 176 °C and 213 °C and 378 °C to 405 °C. The effect of introducing a bicyclohexane group containing a methyl side chain is greater than that of a meta-benzene ring, so COMM (synthesized by Caprolactam (C), dimer oleic acid (OA), and 4,4'-Methylenebis(2-methylcyclohexylamine) (MMCA)) has the lowest melting point, enthalpy, and crystallinity. As the copolymerization ratio increases, its thermal properties decrease. 10% is the lowest crystallinity. The amine structure containing a bicycloalkyl group has lower water absorption and a 10% copolymerization ratio gives the lowest water absorption. It contains the bicycloalkyl group, COM (synthesized by Caprolactam (C), dimer oleic acid (OA) and 4,4'-Methylenebis(cyclohexylamine) (MCA)), which has the highest loss modulus. The lowest loss modulus is noted for a copolymerization ratio of 7% and the value of tan δ increases as the copolymerization ratio increases. The introduction of nylon 6 with the bicycloalkyl groups, COMM and COM, significantly increases transparency. As the copolymerization ratio increases, the transparency increases and the haze decreases. The best optical properties are achieved for 10% copolymerization.
