乳腺癌（BC）具有高的死亡率，约有25-46％的患者PIK3CA基因突变。Alpelisib是一种PI3K抑制剂，作用于PI3K蛋白的p110α亚单位。褪黑素表现出重要的抗肿瘤效应，可能增加化疗的有效性。本研究评估了Alpelisib和褪黑素在携带PIK3CA基因的H1047R突变的BC 细胞系中的协同作用，相对于细胞动力学和PI3K / AKT / mTOR途径。MDA-MB-468（三阴性）、MDA-MB-453（H1047R PIK3CA，HER2+）和T-47D细胞（H1047R PIK3CA，ER+/PR+）被分成四个治疗组：对照组；褪黑素（1mM）；Alpelisib（1μM）；和Alpelisib（1μM）+褪黑素（1mM）。使用MTT和Transwell分析分别研究了细胞存活率和迁移。使用免疫细胞化学验证了PI3K、p-AKT、mTOR、HIF-1α和caspase-3的蛋白表达。 MTT实验显示MDA-MB-453和T-47D在所有组中的细胞存活率均有降低，特别是MDA-MB-453经过褪黑素+Alpelisib治疗。MDA-MB-468仅与褪黑素一起治疗时才表现出细胞迁移减少，而在具有突变的细胞系中，褪黑素+Alpelisib的治疗导致细胞迁移的抑制。在MDA-MB-453和T-47D细胞系中，经过褪黑素+Alpelisib治疗后，PI3K、p-AKT、mTOR和HIF-1α被抑制。在MDA-MB-453和T-47D细胞中所有组的caspase-3表达都增加了，在褪黑素+Alpelisib组中的增加更为明显。这些结果表明，褪黑素和Alpelisib的联合使用可能比任何一种单独治疗更有效地抑制携带PIK3CA基因突变的妇女的BC。版权所有©2023年。Elsevier Inc.出版。

Breast cancer (BC) presents high mortality rate and about 25-46 % have mutation in the PIK3CA gene. Alpelisib is a PI3K inhibitor that acts on p110α, which is a subunit of the PI3K protein. The melatonin shown important anti-neoplastic effects and may increase the effectiveness of chemotherapy. This study evaluated the synergistic action of Alpelisib and Melatonin in BC lines carrying the H1047R mutation in PIK3CA, relative to the cellular dynamics and the PI3K/AKT/mTOR pathway.MDA-MB-468 (triple-ernegative), MDA-MB-453 (H1047R PIK3CA, HER2+) and T-47D cells (H1047R PIK3CA, ER+/PR+) were divided into four treatment groups: control; Melatonin (1 mM); Alpelisib (1 μM); and Alpelisib (1 μM) + Melatonin (1 mM). Cell viability and migration were investigated using the MTT assay and Transwell assay, respectively. Protein expression of PI3K, p-AKT, mTOR, HIF-1α, and caspase-3, was verified using immunocytochemistry.MTT assay revealed that MDA-MB-453 and T-47D showed reduction in cell viability in all groups, especially in the MDA-MB-453 treated with Melatonin + Alpelisib. MDA-MB-468 presents reduction in cell migration only with Melatonin, while in the lines with mutation, the treatment of Melatonin + Alpelisib caused inhibition of cell migration. PI3K, p-AKT, mTOR and HIF-1α were inhibited after treatment with Melatonin + Alpelisib in MDA-MB-453 and T-47D lines. The expression of caspase-3 increased in all groups in MDA-MB-453 and T-47D cells, being the increase more pronounced in the Melatonin + Alpelisib group.These results indicate that the combined use of Melatonin and Alpelisib may be more effective in inhibiting BC in women carrying the PIK3CA gene mutation than either treatment alone.Copyright © 2023. Published by Elsevier Inc.