Panoply™ Human NUAK1 Knockdown Stable Cell Line

NUAK1 is an AMPK-associated kinase located in the cytoplasm and nucleus, and its expression is associated with tumor malignancy and poor prognosis in various cancers. Here, researchers demonstrated that cytoplasmic NUAK1 increases ATP levels, which is associated with enhanced mitochondrial respiration, indicating that cytoplasmic NUAK1 participates in the regulation of mitochondrial function in cancer cells. NUAK1 inhibition leads to the formation of "donut-like" structures, providing evidence for NUAK1-dependent mitochondrial morphology regulation. Furthermore, under the inhibition of mitochondrial function, cytoplasmic NUAK1 enhances the glycolytic capacity of cancer cells. Nuclear NUAK1 appears to be involved in the metabolic shift to glycolysis. In summary, these results suggest that cytoplasmic NUAK1 is involved in mitochondrial ATP production and the maintenance of normal glycolysis in cancer cells. Different subcellular localizations of NUAK1 lead to different metabolic outcomes. The role of NUAK1 in cancer metabolism provides a potential mechanism for tumor progression and its association with poor prognosis in various cancer patients.

Here, to understand the function of NUAK1 in mitochondria, researchers investigated whether it affects mitochondrial morphology and identified reticular, tubular, fragmented, and large round mitochondria (Figure 1A). HTH-01-015 treatment significantly altered the mitochondrial morphology of MCF-7 cells, transforming them from predominantly reticular and tubular structures to large, round mitochondrial structures (Figure 1B, C). Interestingly, green imaging of mitochondria revealed a mitochondrial structure known as a "donut," rather than the typical dotted mitochondria (Figure 1B). To verify whether the morphological observations were related to the specificity of NUAK1 inhibition, researchers constructed NUAK1 knockdown MCF-7 cells and performed mitochondrial morphology analysis. Knockdown of NUAK1 also changed the mitochondrial morphology from reticular to large and round (Figure 1D, E), but fewer "donut" structures were observed compared to the inhibitor-treated group (Figure 1D). On the other hand, overexpression of cytoplasmic NUAK1 had no significant effect on mitochondrial morphology. These data suggest that NUAK1 activity maintains appropriate mitochondrial morphology. Interestingly, HTH-01-015 inhibition of NUAK1 significantly increased mitochondrial volume (Figure 1F), while there was no significant difference in mitochondrial volume among NUAK1 knockdown cells (Figure 1G). This significant difference may be related to the different time points for volume assessment; the HTH-01-015 treatment group was measured after 4 hours, while the NUAK1 knockdown cells were measured after 24 hours. In summary, these data indicate that NUAK1 is essential for maintaining normal mitochondrial morphology in MCF-7 cells.

Figure 1. Downregulation of NUAK1 function induces mitochondrial morphology alterations in MCF-7 cells. (Escalona E, et al., 2020)