Colchicine-Binding Site Agent CH-2-77 as a Potent Tubulin Inhibitor Suppressing Triple-Negative Breast Cancer

Abstract

Triple-negative breast cancer (TNBC) is a highly aggressive type of breast cancer. Unlike other subtypes of breast cancer, TNBC lacks hormone and growth factor receptor targets. Colchicine-binding site inhibitors (CBSIs) targeting tubulin have been recognized as attractive agents for cancer therapy, but there are no CBSI drugs currently FDA-approved. CH-2-77 has been reported to have potent anti-proliferative activity against a panel of cancer cells in vitro and efficacious anti-tumor effects on melanoma xenografts, yet, its anti-cancer activity specifically against TNBC is unknown. Herein, we demonstrate that CH-2-77 inhibits the proliferation of both paclitaxel-sensitive and paclitaxel-resistant TNBC cells with an average IC50 of 3 nM. CH-2-77 also efficiently disrupts the microtubule assembly, inhibits the migration and invasion of TNBC cells, and induces G2/M cell cycle arrest. The increased number of apoptotic cells and the pattern of expression of apoptosis-related proteins in treated MDA-MB-231 cells suggests that CH-2-77 induces cell apoptosis through the intrinsic apoptotic pathway. In vivo, CH-2-77 shows acceptable overall pharmacokinetics and strongly suppresses the growth of orthotopic MDA-MB-231 xenografts without gross cumulative toxicities when administered 5 times a week. The in vivo efficacy of CH-2-77 (20 mg/kg) is comparable to that of CA4P (28 mg/kg), a CBSI that went through clinical trials. Importantly, CH-2-77 prevents lung metastasis originating from the mammary fat pad in a dose-dependent manner. Our data demonstrate that CH-2-77 is a promising new generation of tubulin inhibitors that inhibit the growth and metastasis of TNBC, and it is worthy of further development as an anticancer agent.

S-72, a Novel Orally Available Tubulin Inhibitor, Overcomes Paclitaxel Resistance via Inactivation of the STING Pathway in Breast Cancer

“…Most of the recently reported novel CBSIs are VERU-111 analogues with common known parent nucleus structures, such as SB226 and CH-2-77 [ 16 , 25 ]. The greatest weakness of VERU-111 and its analogues is the relatively low metabolic stability.…”

“…Unlike paclitaxel, colchicine binding site inhibitors (CBSIs) are at less risk of therapeutic resistance. Currently, several novel colchicine binding site inhibitors (CBSIs) are under exploration in studies aiming to combat paclitaxel resistance due to the fact that their binding sites in tubulin are different from that of paclitaxel, as well as their general characteristics and the fact that they are not transported by P-gp [ 12 , 13 , 14 , 15 , 16 ]. However, to date, none of these CBSIs have gained FDA approval, mainly due to their toxicity and lack of clinical benefits, problems that are related to their specific chemical structures.…”

“…Some other compounds are in preclinical studies. Most are CA-4 or VERU-111 analogues with known parent nucleus structures or novel structural compounds such as SB226, which is administered via intraperitoneal or intravenous injection [ 16 , 24 , 25 ]. The development of a new generation of CBSIs with unique chemical structures is urgently required for safe and effective chemotherapy, particularly in the case of paclitaxel-resistant breast cancers.…”

Discovery of a Dual Tubulin and Neuropilin-1 (NRP1) Inhibitor with Potent In Vivo Anti-Tumor Activity via Pharmacophore-based Docking Screening, Structure Optimization, and Biological Evaluation

“…17 Moreover, they can effectively induce G2/M arrest, thereby inhibiting the mitosis and proliferation of tumor cells. 18,19 Thus, CBSIs have been recognized as promising agents for the development of MTAs. Up to now, although a lot of CBSIs such as Combretastatin A-4 (CA-4), Oxi4503, and colchicine have been discovered, there are no Food and Drug Administration (FDA)-approved CBSIs for cancer treatment because of their multiorgan dysfunction and systemic toxicities in clinical trials, prompting further investigation of CBSIs.…”

“…Microtubules are composed of α- and β-tubulin heterodimers, which are major elements of the eukaryotic cytoskeleton. , Microtubule polymerization and depolymerization dynamics are crucial in various cellular functions such as intracellular transport, cell structure maintenance, cell polarity maintenance, and cell mitosis. , Thus, microtubules are attractive targets for cancer therapy, and microtubule target agents (MTAs) have been widely used in clinical fields nowadays. , There are three well-characterized binding sites for MTAs including taxane, vinca alkaloids, and colchicine sites. , Among them, colchicine binding site inhibitors (CBSIs) have a relatively simple structure and better water solubility . Moreover, they can effectively induce G2/M arrest, thereby inhibiting the mitosis and proliferation of tumor cells. , Thus, CBSIs have been recognized as promising agents for the development of MTAs. Up to now, although a lot of CBSIs such as Combretastatin A-4 (CA-4), Oxi4503, and colchicine have been discovered, there are no Food and Drug Administration (FDA)-approved CBSIs for cancer treatment because of their multiorgan dysfunction and systemic toxicities in clinical trials, prompting further investigation of CBSIs. , …”