Inhibition of Cdc20 suppresses the metastasis in triple negative breast cancer (TNBC)

BACKGROUND

Cdc20 is a crucial activator of the anaphase-promoting complex (APC/C) and is known to be essential in mitosis regulation. Abnormally high expression of Cdc20 has been reported in several malignancies. We aimed to study the Cdc20 expression in human breast cancer tissues, focusing specifically on Cdc20 in Triple-Negative Breast Cancer (TNBC).

METHODS

The expression of mitotic regulators mRNA in three TNBC cell lines or three other breast cancer cell lines was determined by the RNA-sequencing database. 14,713 human breast cancer patient samples included in Breast Cancer-GenExminer v4.5 were used to analyze whether cell division cycle 20 (Cdc20) expression was related to TNBC. To find whether Cdc20 expression impacted prognosis in TNBC, we used 2,249 TNBC patients database. The loss of Cdc20 by RNA interference (shRNA) and several mitotic inhibitors including Apcin, ZM447439, BI 2536, and VX-680 on the capacities of proliferation, migration, invasion were evaluated by colony-forming, wound-healing, transwell assay, and western blot, respectively.

RESULTS

We studied the mitosis-related genes and proteins that are closely related to TNBC through the National Center for Biotechnology Information (NCBI) database. We found that Cdc20, one of the central mitotic regulators, is significantly upregulated in human TNBC, and its expression level is positively correlated with metastasis-free and relapse-free patient survival. We also found Cdc20 is highly conserved in TNBC in comparison to other breast cancer subtype cell lines. Cdc20 deficiency results in a decrease in cell growth and migration in four TNBC cell lines. Also, several mitotic inhibitors, such as Apcin, VX-680, ZM447439, and BI 2536, blocked cancer cell growth and invasion.

CONCLUSIONS

These results suggest an essential role of Cdc20 in tumor formation and metastasis of TNBC, which might be a potential target therapy for TNBC treatment.

Microtubule Inhibitors and Cardiotoxicity

PURPOSE OF REVIEW

Cancer and heart disease are the leading causes of mortality in the USA. Advances in cancer therapies, namely, the development and use of chemotherapeutic agents alone or in combination, are becoming increasingly prevalent.

RECENT FINDINGS

Many chemotherapeutic agents have been associated with adverse cardiovascular manifestations. The mechanisms of these sequelae remain incompletely understood. In particular, microtubule inhibitor (MTI) agents have been related to the development of heart failure, myocardial ischemia, and conduction abnormalities. At present, there are no guidelines for patients undergoing MTI therapy as it pertains to both preventative and mitigatory strategies for cardiovascular complications. We conducted a literature review focusing on content related to the use of MTIs and their effect on the cardiovascular system. MTIs have been associated with various forms of cardiotoxicity, and fatal cardiotoxicities are rare. The most well-described cardiotoxicities are brady- and tachyarrhythmias. The co-administration of anthracycline-based agents with MTIs can increase the risk of cardiotoxicity.

The balance between mitotic death and mitotic slippage in acute leukemia: a new therapeutic window?

Mitosis is the process whereby an eukaryotic cell divides into two identical copies. Different multiprotein complexes are involved in the fine regulation of cell division, including the mitotic promoting factor and the anaphase promoting complex. Prolonged mitosis can result in cellular division, cell death, or mitotic slippage, the latter leading to a new interphase without cellular division. Mitotic slippage is one of the causes of genomic instability and has an important therapeutic and clinical impact. It has been widely studied in solid tumors but not in hematological malignancies, in particular, in acute leukemia. We review the literature data available on mitotic regulation, alterations in mitotic proteins occurring in acute leukemia, induction of prolonged mitosis and its consequences, focusing in particular on the balance between cell death and mitotic slippage and on its therapeutic potentials. We also present the most recent preclinical and clinical data on the efficacy of second-generation mitotic drugs (CDK1-Cyclin B1, APC/CCDC20, PLK, Aurora kinase inhibitors). Despite the poor clinical activity showed by these drugs as single agents, they offer a potential therapeutic window for synthetic lethal combinations aimed to selectively target leukemic cells at the right time, thus decreasing the risk of mitotic slippage events.

Anti-mitotic agents: Are they emerging molecules for cancer treatment?

Mutations in cancer cells frequently result in cell cycle alterations that lead to unrestricted growth compared to normal cells. Considering this phenomenon, many drugs have been developed to inhibit different cell-cycle phases. Mitotic phase targeting disturbs mitosis in tumor cells, triggers the spindle assembly checkpoint and frequently results in cell death. The first anti-mitotics to enter clinical trials aimed to target tubulin. Although these drugs improved the treatment of certain cancers, and many anti-microtubule compounds are already approved for clinical use, severe adverse events such as neuropathies were observed. Since then, efforts have been focused on the development of drugs that also target kinases, motor proteins and multi-protein complexes involved in mitosis. In this review, we summarize the major proteins involved in the mitotic phase that can also be targeted for cancer treatment. Finally, we address the activity of anti-mitotic drugs tested in clinical trials in recent years.

Triethylated chromones with substituted naphthalenes as tubulin inhibitors

Previously synthesized 2-(benzo[b]thiophene-3'-yl)-6,8,8-triethyldesmosdumotin B (1, TEDB-TB) and 2-(naphth-1'-yl)-6,8,8-triethyldesmosdumotin B (2) showed potent activity against multiple human tumor cell lines, including a multidrug-resistant (MDR) subline, by targeting spindle formation and/or the microtubule network. Consequently, ester analogues of hydroxylated naphthyl substituted TEBDs (3-5) were prepared and evaluated for their effects on tumor cell proliferation and on tubulin assembly. Among all new compounds, compound 6, a 4'-acetoxynaphthalen-1'-yl derivative, displayed the most potent antiproliferative activity (IC₅₀ 0.2-5.7μM). Selected analogues were confirmed to be tubulin assembly inhibitors in cell-free and cell-based assays using MDR tumor cells. The new analogues partially inhibited colchicine binding to tubulin, suggesting their binding mode would be different from that of colchicine. This observation was supported by computational docking model analyses. Thus, the newly synthesized triethylated chromones with esterified naphthalene groups have good potential for development as a new class of mitotic inhibitors that target tubulin.