Ethyl-2-amino-pyrrole-3-carboxylates are active against imatinib-resistant gastrointestinal stromal tumors in vitro and in vivo

Abstract

We showed recently that ethyl-2-amino-pyrrole-3-carboxylates (EAPCs) exhibit potent antiproliferative activities against a broad spectrum of soft tissue sarcoma and gastrointestinal stromal tumor (GIST) cell lines in vitro. The molecular mechanism of action was owing to inhibition of tubulin polymerization and induction of a robust G2/M cell-cycle arrest, leading to the accumulation of tumor cells in the M-phase and induction of apoptosis. Given that more than 50% of the patients with GISTs develop resistance to imatinib (IM) over the 2 years of IM-based therapy, we examined whether EAPCs exhibit activity against IM-resistant GISTs in vitro and in vivo. A real-time antiproliferation assay illustrated the potent antiproliferative activities of EAPCs against IM-sensitive and IM-resistant GISTs. This was in agreement with the colony formation assay, which revealed potent antiproliferative activities of EAPCs against IM-resistant GISTs, being much stronger when compared with IM and doxorubicin, a topoisomerase II inhibitor. Next, we tested the efficacy of EAPCs in the xenograft model of GISTs, exhibiting secondary IM resistance owing to RTK switch (loss of c-KIT/gain of FGFR2α). A total of 30 5-to 8-week-old female nu/nu mice were subcutaneously inoculated into the flank areas with IM-resistant GIST-T1-R cells (100 μl of 1 × 10 7 GIST T-1R cells/ml suspension, in Dulbecco's PBS). Mice were randomized as control (untreated), IM (50 mg/kg), EAPC-20 (10 mg/kg) or EAPC-24 (10 mg/kg) and were treated orally for 10 days. IM has a minor inhibitory effect on tumor size, thus revealing GIST resistance to IM. In contrast, both of EAPCs effectively reduced the tumor size. This was associated with an increased intratumoral apoptosis as detected by immunohistochemical staining for cleaved caspase-3 on day 5 of the treatment. Furthermore, both EAPCs significantly reduced the proliferative activity of tumor cells in the central zones of tumors as measured by positivity for Ki-67 staining. More importantly, in EAPC-24-treated GISTs, the histological response was mainly characterized by the induction of necrosis, whereas EAPC-20 induced the signs of intratumoral fibrosis and myxoid degeneration. Collectively, our data suggest that EAPC-20 and EAPC-24 are the perspective antitumor agents that exhibit antiproliferative and cytotoxic activity against GISTs exhibiting secondary resistance to IM. Anti-Cancer Drugs 30:475-484

The Design, Synthesis, and Biological Activities of Pyrrole-Based Carboxamides: The Novel Tubulin Inhibitors Targeting the Colchicine-Binding Site

“…Given that the reactions of N-substituted 3-imino(hydrazono)furan-2(3H)-ones with CH-nucleophiles in the presence of triethylamine led to the formation of 2-aminopyrrole derivatives exhibiting potent anticancer activities in vitro and in vivo [ 25 , 26 , 27 , 30 , 31 , 32 ], we synthesized the novel aminopyrrole derivatives. The synthesis of the compounds was carried out according to Scheme 1 .…”

“…Our scientific group also extensively studied the anti-cancer activities of the pyrrole-based 3-carboxylates by using both in vitro and in vivo models. We found for the first time that the cytotoxic and anti-proliferative activities of these compounds were caused by their abilities to interfere with the microtubule dynamic state by inhibiting the tubulin polymerization [ 25 , 26 , 27 ]. This in turn led to the robust cell cycle arrest of cancer cells in the M-phase and induced their apoptosis as an outcome of mitotic catastrophe.…”

“…remains a driving force for the development of the novel potent and less-toxic drugs, which effectively interfere with the microtubules network. We previously reported the potent anti-cancer activities of ethyl-2-amino-pyrrole-3carboxylates (EAPCs) in vitro and in vivo [25][26][27]. The molecular mechanism of action was due to their ability to interfere with the microtubule dynamic state by inhibiting the tubulin polymerization, the induction of the cell cycle arrest in the M-phase, and apoptotic cell death.…”

Mechanisms of cytotoxic activity of pyrrole-carboxamides against multidrug-resistant tumor cell sublines

“…Эти данные согласуются с результатами исследований нашей научной группы, изучающей противоопухолевую активность пиррол-3-карбоксилатов на моделях как in vitro, так и in vivo. Например, мы обнаружили, что цитотоксическая и антипролиферативная активность этих соединений также обусловлена их способностью вмешиваться в динамическое состояние микротрубочек путем ингибирования полимеризации тубулина [25][26][27]. Это, в свою очередь, приводило к остановке клеточного цикла опухолевых клеток в М-фазе и индуцировало их апоптоз в результате незавершенности клеточного цикла.…”

“…Результаты ранее проведенных нами исследований показали высокую цитотоксическую и противоопухолевую активность этил-2-аминопиррол-3-карбоксилатов (пиррол-карбоксамидов, ПК) в отношении довольно широкого спектра опухолевых клеточных линий и ксенографтных опухолей [25][26][27]. Молекулярный механизм их действия обусловлен способностью влиять на динамическое состояние микротрубочек путем ингибирования полимеризации тубулина, что приводит к остановке клеточного цикла в М-фазе и гибели опухолевых клеток по механизму апоптоза.…”