Animacroxam, a Novel Dual-Mode Compound Targeting Histone Deacetylases and Cytoskeletal Integrity of Testicular Germ Cell Cancer Cells

Abstract

Novel approaches for the medical treatment of advanced solid tumors, including testicular germ cell tumors (TGCT), are desperately needed. Especially, TGCT patients not responding to cisplatin-based therapy need therapeutic alternatives, as there is no effective medical treatment available for this particular subgroup. Here, we studied the suitability of the novel dual-mode compound animacroxam for TGCT treatment. Animacroxam consists of an HDAC-inhibitory hydroxamate moiety coupled to a 4,5-diarylimidazole with inherent cytoskeleton disrupting potency. Animacroxam revealed pronounced antiproliferative, cell-cycle arresting, and apoptosis-inducing effects in TGCT cell lines with different cisplatin sensitivities. The IC values of animacroxam ranged from 0.22 to 0.42 μmol/L and were not correlated to the cisplatin sensitivity of the tumor cells. No unspecific cytotoxicity of animacroxam was observed in either cisplatin-sensitive or resistant TGCT cells, even at doses as high as 10 μmol/L. Furthermore, animacroxam induced the formation of actin stress fibers in cancer cells, thereby confirming the cytoskeleton-disrupting and antimigratory properties of its imidazole moiety. When compared with the clinically established HDAC inhibitor vorinostat, the novel dual-mode compound animacroxam exhibited superior antitumoral efficacy Animacroxam also reduced the tumor size of TGCT tumors, as evidenced by performing xenograft experiments on tumor bearing chorioallantoic membranes of fertilizes chicken eggs (CAM assay). The experiments also revealed a very good tolerability of the compound, and hence, animacroxam may be a promising candidate for innovative treatment of TGCT in general and the more so for platinum-insensitive or refractory TGCT..

Antitumor and antiangiogenic activity of the novel chimeric inhibitor animacroxam in testicular germ cell cancer

“…The treatment was well tolerated since food and water consumption of the mice remained unchanged, and no treatment‐induced weight loss or changes in the animals’ behavior was observed. The data confirmed our previous results on low toxicity (Steinemann et al , ) and high tolerability (Höpfner et al , ) of the novel hybrid compound. Based on the initial mouse experiments, additional in vivo studies were performed employing an advanced CAM assay in which the growth of TGCT plaques and their metabolic activity was assessed by MR/PET imaging, a technique that is well established for the clinical assessment of tumor development and metabolic tumor activity in patients (Gebhardt et al , ; Zuo et al , ).…”

Oxazole-Bridged Combretastatin A-4 Derivatives with Tethered Hydroxamic Acids: Structure–Activity Relations of New Inhibitors of HDAC and/or Tubulin Function

“…Imidazole-bridged CA-4 derivatives carrying hydroxamic acid appendages had previously been found to induce alterations of the actin cytoskeleton, such as augmented formation of stress fibers to the effect of an impaired cell motility [34,38]. Such alterations are typical reactions to microtubule destabilization and hyperacetylation of cortactin as a consequence of HDAC6 inhibition [39].…”

“…Recently, we presented conjugates of imidazoles and hydroxamic acids which combine HDAC inhibition with cytoskeletal modulation [34,38,52]. However, conjugates with imidazoles derived from CA-4 had lost crucial CA-4 typical properties such as inhibition of the polymerization of tubulin.…”

Epigenetic treatment combinations to effectively target cisplatin‐resistant germ cell tumors: past, present, and future considerations

“…Another study presented HDAC2 and HDAC3 expression levels being higher than those of HDAC1 in all histological subtypes of GCT, with the exception of choriocarcinomas (Fritzsche et al, 2011). Recently, the novel dual-inhibitor animacroxam (4-(1-methyl-4-anisylimidazol-5-yl)-N-hydroxycinnamide hydrochloride), combining inhibition of HDAC activity and the cellular cytoskeletal dynamics, was shown to have dose-and time-dependent anti-proliferative effects in vitro in 2102Ep and NCCIT cells and in vivo in 2102Ep cells growing on the chicken chorioallantois membrane (CAM) (Steinemann et al, 2017). First studies using HDAC inhibitors (HDACis) depsipeptides, such as romidepsin, valproic acid (VPA), vorinostat (SAHA), trichostatin A (TSA), revealed increased apoptotic cell death in vitro (TCam-2, 2102Ep, NCCIT, NT2/D1, JEG-3, and JAR) and in vivo in mice bearing xenografts developed from 2102Ep or NCCIT (Nettersheim et al, 2011b;Nettersheim et al, 2016aNettersheim et al, ,b, 2019Jostes et al, 2017).…”

“…First studies using HDAC inhibitors (HDACis) depsipeptides, such as romidepsin, valproic acid (VPA), vorinostat (SAHA), trichostatin A (TSA), revealed increased apoptotic cell death in vitro (TCam-2, 2102Ep, NCCIT, NT2/D1, JEG-3, and JAR) and in vivo in mice bearing xenografts developed from 2102Ep or NCCIT (Nettersheim et al, 2011b;Nettersheim et al, 2016aNettersheim et al, ,b, 2019Jostes et al, 2017). Recently, the novel dual-inhibitor animacroxam (4-(1-methyl-4-anisylimidazol-5-yl)-N-hydroxycinnamide hydrochloride), combining inhibition of HDAC activity and the cellular cytoskeletal dynamics, was shown to have dose-and time-dependent anti-proliferative effects in vitro in 2102Ep and NCCIT cells and in vivo in 2102Ep cells growing on the chicken chorioallantois membrane (CAM) (Steinemann et al, 2017). Even though these studies mentioned above also investigated cisplatin-resistant sublines of 2102Ep, NCCIT, and NT2/D1, combined treatment strategies with cisplatin would be indicative for additive or synergistic effects and should be further investigated.…”