Growth Inhibition Activity Assessment of γ-Lactam-Containing Chemicals in Cultured MCF-7 Cells and Xenografted Chick Embryos

We evaluated the growth-inhibitory effects of three γ-butyrolactam (γ-lactam) derivatives (compounds 5, 6, and 8) on human breast cancer cells (MCF-7) and in a xenografted chick model. Growth inhibition was assessed using MTT assays and flow cytometry for compounds 5, 6, and 8, followed by Western blot analysis to examine the expression levels of cell cycle-associated proteins. Chick embryos were utilized as a xenograft model for further validation. The results revealed that compound 8 exhibited relatively low toxicity among the tested compounds. Western blot analysis suggested that compounds 5, 6, and 8 may be involved in the EGFR and P53 signaling pathways. In the xenograft model, compound 8 significantly inhibited MCF-7 tumor growth in chick embryos (tumor size in control group: 1.97 ± 0.69 mm, n = 15; compound 8-treated group: 1.20 ± 0.37 mm, n = 15). These findings suggest that compound 8 effectively inhibits MCF-7 growth with minimal toxicity, warranting further investigation in mammalian models.