Targeting TAO Kinases Using a New Inhibitor Compound Delays Mitosis and Induces Mitotic Cell Death in Centrosome Amplified Breast Cancer Cells

Abstract

Thousand-and-one amino acid kinases (TAOK) 1 and 2 are activated catalytically during mitosis and can contribute to mitotic cell rounding and spindle positioning. Here, we characterize a compound that inhibits TAOK1 and TAOK2 activity with IC values of 11 to 15 nmol/L, is ATP-competitive, and targets these kinases selectively. TAOK inhibition or depletion in centrosome-amplified SKBR3 or BT549 breast cancer cell models increases the mitotic population, the percentages of mitotic cells displaying amplified centrosomes and multipolar spindles, induces cell death, and inhibits cell growth. In contrast, nontumorigenic and dividing bipolar MCF-10A breast cells appear less dependent on TAOK activity and can complete mitosis and proliferate in the presence of the TAOK inhibitor. We demonstrate that TAOK1 and TAOK2 localize to the cytoplasm and centrosomes respectively during mitosis. Live cell imaging shows that the TAOK inhibitor prolongs the duration of mitosis in SKBR3 cells, increases mitotic cell death, and reduces the percentages of cells exiting mitosis, whereas MCF-10A cells continue to divide and proliferate. Over 80% of breast cancer tissues display supernumerary centrosomes, and tumor cells frequently cluster extra centrosomes to avoid multipolar mitoses and associated cell death. Consequently, drugs that stimulate centrosome declustering and induce multipolarity are likely to target dividing centrosome-amplified cancer cells preferentially, while sparing normal bipolar cells. Our results demonstrate that TAOK inhibition can enhance centrosome declustering and mitotic catastrophe in cancer cells, and these proteins may therefore offer novel therapeutic targets suitable for drug inhibition and the potential treatment of breast cancers, where supernumerary centrosomes occur. .

The Diverse Roles of TAO Kinases in Health and Diseases

“…TAOKs modulate the dynamics and organization of several cytoskeleton components [ 29 , 30 , 31 ]. TAOKs are activated catalytically during mitosis and neuritogenesis [ 32 , 33 , 34 , 35 , 36 ]. By phosphorylation of microtubule-binding proteins including tau, TAOK1 induces microtubule instability by causing dissociation of tau from microtubules, which results in their disassembly [ 30 , 31 , 37 ] ( Figure 3 A).…”

“…TAOK2 was found to increase the levels of acetylated α-tubulin when associated with microtubules and also to bind and phosphorylate α- and β-tubulin in vitro [ 29 ]. It was demonstrated that in mitotic cells, activated TAOK1 localizes to the cytoplasm while TAOK2 localizes to the centrosomes, and both TAOKs are required for spindle positioning and mitotic cell rounding [ 33 , 35 ]. Garg et al [ 38 ] further showed that TAOK1 and 2 bind and phosphorylate the atypical Rho family protein Rnd3 and elicit the translocation of Rnd3 from the plasma membrane to the cytosol, which contributes to spindle positioning, mitotic cell rounding, and cytokinesis ( Figure 3 A).…”

“…The MST1 inhibitor 9E1 suppresses TAOK2 activity with an IC50 value of 0.3 μmol/L [ 83 ]; yet it has the same specificity issue as staurosporine. Recently, two TAOK inhibitors, compounds 43 and 63, were isolated with high specificity to TAOK1, 2, and 3 [ 33 ]. Both compounds are ATP-competitive inhibitors of TAOK activity.…”

“…Both compounds are ATP-competitive inhibitors of TAOK activity. Compound 43 (N-[2-oxo-2-(1,2,3,4-tetrahydro-naphthalen-1-ylamino)ethyl]biphenyl-4-carboxamide) was found to target and inhibit cancer cells selectively while not affecting non-tumor cells [ 33 ]. Compound 43 prolongs the duration of mitosis, reduces the percentage of cells exiting mitosis, and increases mitotic cell death in cancer cells, while non-malignant MCF-10A breast cells continue to proliferate normally [ 33 ].…”

Transcriptome analysis reveals gender-specific differences in overall metabolic response of male and female patients in lung adenocarcinoma

“…TAOK1 and TAOK2 are catalytically activated during mitosis and can contribute to mitotic cell rounding and spindle positioning. A recent study showed that TAOK inhibition prolongs the duration of mitosis in breast cancer cells, increases mitotic cell death, and reduces the percentage of cells exiting mitosis [30]. Furthermore, genetic analyses identified a rare TAOK2 homozygous missense variant that causes a novel form of primary immunodeficiency [31].…”