Purpose: AKT hyperactivation drives malignant phenotypes in lung cancer via promoting tumor cell proliferation and survival. However, the relationship between dysregulation of cell cycle progression and AKT1 kinase activity is still not clear.
Methods: Following the expression level of PKMYT1 in lung cancer, we performed cell proliferation, migration, invasion, and xenograft assays to determine the function of PKMYT1. We used RNA-seq to explore the anti-tumor mechanism of PKMYT1 and examined the effect of PKMYT1 on AKT1 activity.
Results: In this study, we report that PKMYT1 is downregulated in lung adenocarcinoma (LUAD) tissues and its low expression predicts a poor prognosis in LUAD patients. PKMYT1 exerts potent tumor-suppressive functions in LUAD cells by inhibiting AKT1 activation and thereby repressing cell cycle progression, which depends on its tyrosine and threonine protein kinase activity. Interestingly, PKMYT1 could directly bind AKT1 to abrogate AKT1 activation. Moreover, silencing AKT1 and inhibitors targeting the AKT pathway effectively reverse the promoting effects of PKMYT1 knockdown on proliferation, migration and invasion of LUAD cells.
Conclusion: This work reveals the anti-tumor effect of PKMYT1 in LUAD and provides evidence to clarify the dual roles of PKMYT1 in tumor progression. Moreover, our findings broaden the current understandings on AKT1 activation and identify PKMYT1 as a potential negative regulator of AKT1 kinase activity, providing further insights into targeting the AKT pathway in LUAD.
Keywords: AKT1; Cell cycle; Lung adenocarcinoma; PKMYT1.
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