Chemistry Department, Eastern Michigan University, Ypsilanti, MI, 48197, USA.
Sci Rep. 2021 May 6;11(1):9708. doi: 10.1038/s41598-021-88574-0.
In this study, we set out to identify regulators of intact amyloid-β40/42 (Aβ) levels in A549 (p53 wild-type) and H1299 (p53-null) lung cancer cell media. Higher Aβ levels were detected in the media of A549 than H1299 cells without or with treatment with 4-methylumbelliferone (4-MU) and/or the anti-CD44 antibody (5F12). Using inhibitors, we found that PI3K, AKT, and NFκB are likely involved in regulating Aβ levels in the media. However, increased Aβ levels that more closely resembled those found upon 4-MU co-treatment resulted from MMP2/9 inhibition, suggesting that MMP2/9 maybe the main contributors to regulation of Aβ levels in the media. Differences in Aβ levels might be accounted for, in part, by p53 since blocking p53 function in A549 cells resulted in decreased Aβ levels, increased MMP2/9 levels, increased PI3K/AKT activities and the phospho/total NFκB ratio. Using siRNA targeted against MMP2 or MMP9, we found increased Aβ levels in the media, however, MMP2 knockdown led to Aβ levels closely mimicking those detected by co-treatment with 4-MU. Cell viability or apoptosis upon treatment with either MMP2 or MMP9 siRNA along with Aβ immunodepletion, showed that MMP2 is the predominant regulator of the cytotoxic effects induced by Aβ in lung cancer cells.
在这项研究中，我们旨在确定 A549（野生型 p53）和 H1299（p53 缺失型）肺癌细胞培养基中完整的淀粉样蛋白β40/42（Aβ）水平的调节剂。在未用或用 4-甲基伞形酮（4-MU）和/或抗 CD44 抗体（5F12）处理的情况下，A549 细胞培养基中的 Aβ水平高于 H1299 细胞。使用抑制剂，我们发现 PI3K、AKT 和 NFκB 可能参与调节培养基中的 Aβ水平。然而，更类似于用 4-MU 共同处理时发现的 Aβ水平的增加是由于 MMP2/9 抑制所致，这表明 MMP2/9 可能是调节培养基中 Aβ水平的主要因素。Aβ水平的差异可能部分归因于 p53，因为阻断 A549 细胞中的 p53 功能会导致 Aβ水平降低、MMP2/9 水平增加、PI3K/AKT 活性增加和磷酸化/总 NFκB 比值增加。使用针对 MMP2 或 MMP9 的 siRNA，我们发现培养基中的 Aβ 水平增加，然而，MMP2 敲低导致 Aβ 水平与用 4-MU 共同处理时检测到的水平非常相似。用 MMP2 或 MMP9 siRNA 与 Aβ 免疫耗竭处理后，细胞活力或凋亡表明 MMP2 是 Aβ在肺癌细胞中诱导细胞毒性作用的主要调节剂。
