Deletion of arylamine N‐acetyltransferase 1 in MDA‐MB‐231 human breast cancer cells reduces primary and secondary tumor growth in vivo with no significant effects on metastasis

Abstract

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.

Stable Isotope Tracing Reveals an Altered Fate of Glucose in N-Acetyltransferase 1 Knockout Breast Cancer Cells

“…Studies have utilized both small molecule-mediated inhibition and CRISPR/Cas9 NAT1 KO to investigate the role of NAT1 in breast cancer cell lines. Although there have been some discrepancies reported between studies, there is consensus that NAT1 inhibition or NAT1 KO in cultured breast cancer cells results in cell growth retardation and reduced migration/invasion [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Further, the inhibition or loss of NAT1 results in a loss of the ability of breast cancer cells to grow in an anchorage-independent manner (growth in soft agar).…”

“…Further, the inhibition or loss of NAT1 results in a loss of the ability of breast cancer cells to grow in an anchorage-independent manner (growth in soft agar). NAT1 KO in MDA-MB-231 breast cancer cells reduced anchorage-independent colony formation and primary and secondary tumors in immunocompromised mice [ 14 , 15 , 17 , 19 , 20 ].…”