Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA.
Department of Medicine, University of Louisville, Louisville, Kentucky, USA.
Mol Carcinog. 2022 May;61(5):481-493. doi: 10.1002/mc.23392. Epub 2022 Feb 8.
Arylamine N-acetyltransferase 1 (NAT1) is frequently upregulated in breast cancer. Previous studies showed that inhibition or depletion of NAT1 in breast cancer cells diminishes anchorage-independent growth in culture, suggesting that NAT1 contributes to breast cancer growth and metastasis. To further investigate the contribution of NAT1 to growth and cell invasive/migratory behavior, we subjected parental and NAT1 knockout (KO) breast cancer cell lines (MDA-MB-231, MCF-7, and ZR-75-1) to multiple assays. The rate of cell growth in suspension was not consistently decreased in NAT1 KO cells across the cell lines tested. Similarly, cell migration and invasion assays failed to produce reproducible differences between the parental and NAT1 KO cells. To overcome the limitations of in vitro assays, we tested parental and NAT1 KO cells in vivo in a xenograft model by injecting cells into the flank of immunocompromised mice. NAT1 KO MDA-MB-231 cells produced primary tumors smaller than those formed by parental cells, which was contributed by an increased rate of apoptosis in KO cells. The frequency of lung metastasis, however, was not altered in NAT1 KO cells. When the primary tumors of the parental and NAT1 KO cells were allowed to grow to a pre-determined size or delivered directly via tail vein, the number and size of metastatic foci in the lung did not differ between the parental and NAT1 KO cells. In conclusion, NAT1 contributes to primary and secondary tumor growth in vivo in MDA-MB-231 breast cancer cells but does not appear to affect its metastatic potential.
芳香胺 N-乙酰基转移酶 1（NAT1）在乳腺癌中经常上调。先前的研究表明，抑制或耗尽乳腺癌细胞中的 NAT1 会减少培养中的无锚定生长，表明 NAT1 有助于乳腺癌的生长和转移。为了进一步研究 NAT1 对生长和细胞侵袭/迁移行为的贡献，我们对亲本和 NAT1 敲除（KO）乳腺癌细胞系（MDA-MB-231、MCF-7 和 ZR-75-1）进行了多项检测。在所测试的细胞系中，NAT1 KO 细胞的悬浮细胞生长速度并没有一致降低。同样，细胞迁移和侵袭测定也未能在亲本和 NAT1 KO 细胞之间产生可重复的差异。为了克服体外测定的局限性，我们在异种移植模型中通过将细胞注射到免疫缺陷小鼠的侧腹中来测试亲本和 NAT1 KO 细胞。NAT1 KO MDA-MB-231 细胞产生的原发性肿瘤比亲本细胞形成的肿瘤小，这是由于 KO 细胞中凋亡率增加所致。然而，NAT1 KO 细胞中的肺转移频率没有改变。当允许亲本和 NAT1 KO 细胞的原发性肿瘤生长到预定大小或直接通过尾静脉递送时，肺中的转移灶的数量和大小在亲本和 NAT1 KO 细胞之间没有差异。总之，NAT1 有助于 MDA-MB-231 乳腺癌细胞体内原发性和继发性肿瘤的生长，但似乎不会影响其转移潜力。
