Practical lessons learned from real-world implementation of the molecular classification for endometrial carcinoma.

OBJECTIVES: This study aimed to explore the practical organisational aspects and difficulties in the implementation of the molecular classification of endometrial carcinoma (EC), and to demonstrate its potential impact in prognostic risk group classification. METHODS: We conducted a multicentre, retrospective cohort study of 230 patients with EC diagnosed between 2019 and 2022. Sample processing, clinicopathological, treatment and follow-up data were collected. Molecular classification was obtained by p53 and mismatch repair proteins immunohistochemistry, and POLE next-generation sequencing. RESULTS: Implementation was achieved through centralization of molecular analysis. In practice, it was possible to optimise turnaround times of complete integrative reports for hysterectomy specimens to a median time of 18 workdays. If genetic study was started in endometrial biopsies before surgery, 82.0% were available at the time of multidisciplinary tumour board, compared to 8.4% if performed in hysterectomy. ECs were classified as follows: 37.8% no specific molecular profile, 31.7% p53 abnormal, 24.3% mismatch repair deficient, and 6.1% POLE mutant. Integration of these results with traditional clinicopathologic factors led to a change in prognostic risk group in 15 (6.5%) patients, most being initially allocated to high-intermediate (n = 8) and low (n = 5) risk groups. Eight patients changed to a higher risk, and 7 to a lower risk group, whereas 2 remained in the same group. CONCLUSIONS: Centralization of EC molecular classification is a feasible option for countries with limited resources. Optimization of workflows may be achieved by earlier analysis in biopsies and prioritisation of patients whose results imply changes in risk group classification.

BP-M345, a New Diarylpentanoid with Promising Antimitotic Activity.

Previously, we reported the in vitro growth inhibitory effect of diarylpentanoid BP-M345 on human cancer cells. Nevertheless, at that time, the cellular mechanism through which BP-M345 exerts its growth inhibitory effect remained to be explored. In the present work, we report its mechanism of action on cancer cells. The compound exhibits a potent tumor growth inhibitory activity with high selectivity index. Mechanistically, it induces perturbation of the spindles through microtubule instability. As a consequence, treated cells exhibit irreversible defects in chromosome congression during mitosis, which induce a prolonged spindle assembly checkpoint-dependent mitotic arrest, followed by massive apoptosis, as revealed by live cell imaging. Collectively, the results indicate that the diarylpentanoid BP-M345 exerts its antiproliferative activity by inhibiting mitosis through microtubule perturbation and causing cancer cell death, thereby highlighting its potential as antitumor agent.

Tetracyclic Thioxanthene Derivatives: Studies on Fluorescence and Antitumor Activity.

Thioxanthones are bioisosteres of the naturally occurring xanthones. They have been described for multiple activities, including antitumor. As such, the synthesis of a library of thioxanthones was pursued, but unexpectedly, four tetracyclic thioxanthenes with a quinazoline-chromene scaffold were obtained. These compounds were studied for their human tumor cell growth inhibition activity, in the cell lines A375-C5, MCF-7 and NCI-H460. Photophysical studies were also performed. Two of the compounds displayed GI50 values below 10 µM for the three tested cell lines, and structure-activity relationship studies were established. Three compounds presented similar wavelengths of absorption and emission, characteristic of dyes with a push-pull character. The structures of two compounds were elucidated by X-ray crystallography. Two tetracyclic thioxanthenes emerged as hit compounds. One of the two compounds accumulated intracellularly as a bright fluorescent dye in the green channel, as analyzed by both fluorescence microscopy and flow cytometry, making it a promising theranostic cancer drug candidate.

Navitoclax Enhances the Therapeutic Effects of PLK1 Targeting on Lung Cancer Cells in 2D and 3D Culture Systems.

The efficacy of antimitotics is limited by slippage, whereby treated cells arrested in mitosis exit mitosis without cell division and, eventually, escape apoptosis, constituting a serious resistance mechanism to antimitotics. Strategies to overcome slippage should potentiate the cancer cell killing activity of these antimitotics. Such strategies should accelerate cell death in mitosis before slippage. Here, we undertook a mechanistic analysis to test whether the apoptosis activator Navitoclax potentiates apoptosis triggered by the antimitotic BI2536, a potent inhibitor of Polo-like kinase 1 (PLK1) with the goal of overcoming slippage. We found that cancer cells in 2D cultures treated with BI2536 alone accumulate in mitosis, but a significant fraction of arrested cells undergo slippage and survive. Remarkably, combining BI2536 with Navitoclax dramatically reduces slippage, shifting the cell fate to accelerated death in mitosis. The results are confirmed in 3D spheroids, a preclinical system that mimics in vivo tumor drug responses. Importantly, in 3D spheroids, the effect of the BI2536/Navitoclax combination requires a lower therapeutic dosage of each drug, underlying its potential to improve the therapeutic index. Our results highlight the relevance of apoptosis potentiators to circumvent slippage associated with antimitotics. The combination of BI2536 with Navitoclax shows in vitro synergy/additive effect, which warrants further clinical research.

Second-Generation Antimitotics in Cancer Clinical Trials.

Mitosis represents a promising target to block cancer cell proliferation. Classical antimitotics, mainly microtubule-targeting agents (MTAs), such as taxanes and vinca alkaloids, are amongst the most successful anticancer drugs. By disrupting microtubules, they activate the spindle assembly checkpoint (SAC), which induces a prolonged delay in mitosis, expected to induce cell death. However, resistance, toxicity, and slippage limit the MTA's effectiveness. With the desire to overcome some of the MTA's limitations, mitotic and SAC components have attracted great interest as promising microtubule-independent targets, leading to the so-called second-generation antimitotics (SGAs). The identification of inhibitors against most of these targets, and the promising outcomes achieved in preclinical assays, has sparked the interest of academia and industry. Many of these inhibitors have entered clinical trials; however, they exhibited limited efficacy as monotherapy, and failed to go beyond phase II trials. Combination therapies are emerging as promising strategies to give a second chance to these SGAs. Here, an updated view of the SGAs that reached clinical trials is here provided, together with future research directions, focusing on inhibitors that target the SAC components.