Haspin inhibition delays cell cycle progression through interphase in cancer cells

Abstract

Haspin (Haploid Germ Cell-Specific Nuclear Protein Kinase) is a serine/threonine kinase pertinent to normal mitosis progression and mitotic phosphorylation of histone H3 at threonine 3 in mammalian cells. Different classes of small molecule inhibitors of haspin have been developed and utilized to investigate its mitotic functions. We report herein that applying haspin inhibitor CHR-6494 or 5-ITu at the G1/S boundary could delay mitotic entry in synchronized HeLa and U2OS cells, respectively, following an extended G2 or the S phase. Moreover, late application of haspin inhibitors at S/G2 boundary is sufficient to delay mitotic onset in both cell lines, thereby, indicating a direct effect of haspin on G2/M transition. A prolonged interphase duration is also observed with knockdown of haspin expression in synchronized and asynchronous cells. These results suggest that haspin can regulate cell cycle progression at multiple stages at both interphase and mitosis. K E Y W O R D Scell cycle, haspin, kinase, mitosis

Evaluation of the antiproliferative effects of the HASPIN inhibitor CHR-6494 in breast cancer cell lines

“…However, this increase in MPM-2 positive (mitotic) cells cannot fully explain the increase in the fraction of G2/M cells resulting from CHR-6494 treatment ( Fig 3A ), indicating that the majority of arrested cells would be in G2. These results are consistent with previous reports indicating that HASPIN depletion leads to cell cycle arrest at both interphase and mitosis [ 8 , 19 , 29 ]. To examine the effects of CHR-6494 on apoptosis, we stained cells with Annexin V-fluorescein isothiocyanate (FITC)/PI.…”

A Peak of H3T3 Phosphorylation Occurs in Synchrony with Mitosis in Sea Urchin Early Embryos

“…We have shown that the echinoidea species have a single Haspin homolog and that this protein contains a Ser/Thr kinase domain exhibiting all the typical structural features of its mammalian counterparts, including a well-conserved catalytic region (Figure 4). We have thus tried to block the activity of this kinase in vivo using the CHR-6494 inhibitor, a small molecule known to prevent T3H3 phosphorylation in both human and murine cells [31][32][33]41]. We found that the administration of this inhibitor does not have a direct impact on the T3H3ph levels displayed during mitosis (Figure 7).…”

“…Moreover, the use of Haspin inhibitors has shown that this kinase is also required during meiosis [31,32]. However, much remains to be done, as Haspin is likely to play a biological role also during interphase [33] and H3 might not be its sole relevant substrate [34,35].…”

Bioinformatic analysis reveals GSG2 as a potential target for breast cancer therapy

“…GSG2 has been proved to be a serine/threonine kinase that phosphorylates histone 3 during mitosis and plays an important role in regulating chromosome behavior during cell division [ 3 , 6 , 7 ]. Because of its essential activities in mitosis, GSG2 inhibitors have been developed as potential anti-cancer drugs recently [ 16 , 17 , 18 , 19 ]. Lili Han et al found that haspin inhibitor CHR-6494 inhibited the viability of several melanoma cell lines [ 20 ].…”